xvEPA
United States
Environmental Protection
Agency
Industrial Environmental Research EPA-600/7-79-037a
Laboratory February 1979
Research Triangle Park NC 27711
Design Optimization
and Field Verification
of an Integrated
Residential Furnace-
Phase 1
Interagency
Energy/Environment
R&D Program Report
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U S Environmental
Protection Agency, have been grouped into nine series These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are.
1 Environmental Health Effects Research
2 Environmental Protection Technology
3. Ecological Research
4 Environmental Monitoring
5 Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series Reports in this series result from the
effort funded under the 17-agency Federal Energy/Environment Research and
Development Program These studies relate to EPA's mission to protect the public
health and welfare from adverse effects of pollutants associated with energy sys-
tems. The goal of the Program is to assure the rapid development of domestic
energy supplies in an environmentally-compatible manner by providing the nec-
essary environmental data and control technology Investigations include analy-
ses of the transport of energy-related pollutants and their health and ecological
effects, assessments of, and development of. control technologies for energy
systems, and integrated assessments of a wide-range of energy-related environ-
mental issues.
EPA REVIEW NOTICE
This report has been reviewed by the participating Federal Agencies, and approved
for publication. Approval does not signify that the contents necessarily reflect
the views and policies of the Government, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161
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EPA-600/7-79-037a
February 1979
Design Optimization and Field
Verification of an Integrated
Residential Furnace-
Phase 1
by
A.S. Okuda and LP. Combs
Rockwell International
Rocketdyne Division
6633 Canoga Avenue
Canoga Park, California 91304
Contract No. 68-02-2174
Program Element No. EHE624A
EPA Project Officer: G. Blair Martin
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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ABSTRACT
The report describes the first phase of an investigation to further optimize
the design of a prototype low-emission residential furnace, that was derived
from earlier EPA-funded studies, and to obtain field verification of its
emission and performance characteristics. Details are given concerning three
major subdivisions of work in Phase I, namely: (1) analytical and experimental
studies to optimize the furnace design and its nominal operating ranges, and
to ensure conformance with appropriate safety standards; (2) planning all
aspects of the subsequent (Phase II) field test investigation, including
selection of test locales and host homes, provision of local installation and
service support, and all logistic and scheduling considerations; and (3)
studies of the integrated furnace's capabilities to function properly with
alternate fuels, such as natural gas and methanol.
iii
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CONTENTS
Abstract ill
Figures vi
Tables vii
1. Introduction 1
2. Conclusions 3
3. Recommendations 6
4. Summary of the Protytype Furnace Investigation 7
Prototype Furnace Description 7
Laboratory Facility 9
Prototype Furnace Results 11
5. Integrated Furnace Design Optimization 14
Modifications for the Integrated Furnace 14
Laboratory Tests of the Prototype and First Integrated
Furnaces 17
Finalized Design of the Integrated Furnace 34
Laboratory Verification Studies 37
6. Field Verification 42
Test Locale Selection 42
Support in Test Locales 45
Test Measurements 47
7. Evaluation of the Use of Other Fuels 51
Selection of Candidate Fuels 51
Natural Gas 52
Methanol 70
Alternate Fuels Evaluation 75
References 79
Appendices
A. Cast Firebox Material Selection 82
B. Data Tabulations: Prototype Furnace Experiments 85
C. Data Tabulations: Integrated Furnace Optimization
Experiments 87
D. Underwriters Laboratories Report of Preliminary Investigation
and Appropriate Rocketdyne Response 106
E. Flue Gas Pollutant Emission Concentrations From Integrated
Furnace Field Test Unit 2 at 0.79 ml/s (3/4 gph)
Firing Rate 116
F. Summary of Discussions at the Final Field Test- Planning
Meeting, 7 July 1977 117
G. Information for Homeowners 146
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FIGURES
Number
1 Prototype furnace modified components 8
2 Schematic of the furnace performance evaluation system ... 10
3 Cycle-averaged NO emissions 12
4 Pseudo-steady-state thermal efficiencies 13
5 Combustion air inlet, draft-flap assembly for the optimum
low-emission burner 15
6 Electrical circuit schematic showing the inlet draft flap
microswitch supplement to the flame detector circuit ... 16
7 Cast-formed air-cooled combustion chamber 18
8 Drawing of the cast iron finned combustor for the integrated
furnace system 19
9 Throttled exit air-flow characteristics 21
10 Inlet throttling air-flow characteristics 21
11 Steady-state temperature distribution on the finned prototype
combustion with 0.025 M exposed fin length 24
12 Steady-state surface temperature distribution on the cast-formed
combustor installed in the integrated furnace system ... 24
13 Combustion gas temperatures at exits of heat exchanger panels . 27
14 Combustion gas temperatures at exits of heat exchanger panels
with full-length control vanes installed in the two
outer panels 28
15 Thermal efficiencies of the Integrated and the stock furnaces . 30
16 Cycle-averaged smoke emission characteristics of the integrated
furnace tested on 4-minute-on/8-minute-off firing cycles . . 33
17 Optimum low-emission oil burner 35
18 Internal construction of the integrated furnace 36
19 Schematic of automatic field test furnace efficiency data
acquisition system 49
20 Exploded view of a forced draft power gas burner 55
21 Suggested general dimensions of vertical and horizontal
draft hoods 58
22 Conversion of the low-emission optimum burner to natural gas . 66
23 Dimensions and specifications for the Midco DS5850 burner . . 67
vi
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TABLES
Number Page
1 Comparison of Pollutant Emissions From Various Residential
Furnaces !2
2 Listing of Underwriter Laboratories Performance Testing
Requirements 39
3 Maximum Temperature Rises Measured on the Integrated Furnace
Tested in Compliance With Underwriters Laboratories
Specifications . . . . 41
4 Pertinent Housing Characteristics for Eleven Candidate Cities . 44
5 Average Laboratory-Test Emissions of Atmospheric Injection
Forced Air Furnaces 60
6 Summary of Residential Gas Heating Source Sampling Results . . 62
7 Comparison of Air Pollutant Emissions From Natural Gas and Oil-
Fueled Residential Space Heating Systems 63
8 Flue Gas Emissions Results Using Natural Gas as Fuel in the
Integrated Furnace System With a Midco Model DS5850 Burner . 69
9 Flue Gas Emissions Results Using Methanol as Fuel in the Integrated
Furnace System With the Optimum Burner 74
10 Estimated Maximum Achieveable Thermal Efficiency Based on the
Influence of Water Vapor in the Combustion Products of
Three Fuels 76
vii
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SECTION 1
INTRODUCTION
Under a previous EPA contract (Ref. 1), design criteria were determined
whereby gun-type pressure-atomizing distillate oil burners, such as are com-
monly used in residential and commercial space-heating systems, may be modi-
fied so that they produce substantially lower emissions of oxides of nitrogen
(NOX) and burn smoke-free at more efficient operating conditions. Those de-
sign criteria were used to modify existing burners of two sizes—a 1.05 ml/s
(1.0 gph) residential burner and a 9.47 ml/s (9.0 gph) commercial burner—and
were demonstrated to be valid in laboratory testing.
Further laboratory research, under another EPA contract and with the smaller
of those two low-emission oil burners, provided additional design criteria for
fireboxes matched to the burner to achieve even lower NOX emissions (Ref. 2).
Thereafter, proof-of-concept experiments were carried out in the laboratory
using a prototype residential warm-air furnace embodying the several design
criteria (Ref. 3 and 4). The resultanc NO emissions were reduced to about
35% of the estimated average from comparable, existing, installed units. Fur-
ther, the laboratory performance data showed that the prototype furnace's
cycle-averaged thermal efficiency should be 10 or more percentage points
higher than the estimated average of the existing residential oil furnace
population.
The present investigation is a logical continuation from those encouraging
laboratory results. Potential benefits of commercializing the derived tech-
nology are to be demonstrated by conducting field tests of several low-
emission furnaces in actual residences. First, however, it was appropriate to
effect further refinements of the burner and furnace designs, partially to
further optimize emissions and efficiency performance and partially to Improve
commercial producibility. Thus, the two objectives of this investigation
have been: (1) beginning with the prototype furnace tested earlier, to fur-
ther optimize the design of an integrated, low-emission, high-performance,
oil-fueled, residential warm-air furnace; and (2) to verify its pollutant
emissions and thermal efficiency performance by operating units over an entire
winter heating season in actual residential installations.
The investigation is being performed in two phases. In Phase I, further de-
sign optimization has been approached by making modifications to the proto-
type low-emission furnace described in Ref. 3, and retesting the unit in a
Rocketdyne laboratory. Eventually, this led to the construction and verifi-
cation testing of a second, all-new, integrated furnace unit prior to assem-
bly of six units of the final design to be installed in the field.
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Simultaneously pursued was the definition of field test requirements, com-
prised of selecting test locales, arranging for local support, selecting host
residences, considering the logistics of shipping, installing,activating, and
servicing, measuring performance and, finally, removing the experimental fur-
naces and restoring the host homes' heating systems to their former condi-
tions. Phase II, which is currently being performed and will continue through
the summer of 1978, is concerned with construction, shipment, and installa-
tion of the field test units, as well as with monitoring their performance and
emissions and, finally, interpreting and reporting the results.
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SECTION 2
CONCLUSIONS
Based on the experimental investigation to optimize further the prototype low-
emission residential furnace (derived from Contract 68-02-1819) into an inte-
grated furnace design amenable for field verification testing, it was con-
cluded that:
1. Cast-forming of gray iron is the preferred method for fabricating
the integrated furnace's finned, air-cooled combustor.
2. A satisfactory, leak-proof joint between the cast-iron firebox and
steel heat exchanger may be formed by casting a cylindrical steel
band into the exhaust port of the firebox and welding the heat ex-
changer to that band.
3. The effectiveness of heat extraction from the flue gases is influ-
enced only slightly by variations in: (a) the air flow patterns
over the outside of the air-cooled firebox and air-cooled primary
heat exchanger, and (b) the flue gas distribution pattern within
the heat exchanger. Proportionately greater heat extraction would
require either a larger heat exchanger or a lower furnace firing
rate.
4. To satisfy the target firing-cycle-averaged smoke emission require-
ment of < No. 1 smoke on the Bacharach scale, it was necessary to
change the integrated furnaces's nominal operating set point from
1.05 ml/s (1.0 gph) and 15% excess air to 0.79 ml/s (0.75 gph) fir-
ing rate and 20% excess air. (This was attributed to the smoke
measurements having been erroneously low during much of the pre-
vious prototype furnace investigation.)
5. Installation of a flanged ring on the outer perimeter of the simu-
lated, stamped sheet metal burner head also aided in minimizing
smoke emissions by preventing uncontrolled leakage of combustion
air away from the main flame zone.
6. Combustion with low-temperature outdoor ambient air, admitted
through the furnace's sealed air system, is accompanied by a modest
increase in excess air level as the temperature falls. The emis-
sions of air pollutants remain essentially invariant, even to sub-
zero temperatures.
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7. The integrated furnace conforms sufficiently closely to the Under-
writers Laboratories (UL) safety requirements that it will not con-
stitute a safety hazard for either host homes or service personnel
in a field testing investigation. (This assessment is based on:
(1) a limited, nontesting preliminary investigation by UL, (2)
Rocketdyne's design modifications in response to UL's observations,
and (3) Rocketdyne testing of integrated furnace behavior under
limit variation conditions.)
Based on the preparations for field testing, it was concluded that:
1. Conducting the field tests in the vicinities of Boston, Mass., and
Albany, N.Y., will provide adequate test furnace exposure to two
distinctly different winter climates in communities having a large
porportion of homes heated by fuel oil and an adequate proportion
of basement installations of warm-air furnaces.
2. In Massachusetts, approval of the burner design is required before
field test furnaces can be installed in homes. Otherwise, no
formal government sanctions or independent laboratory certifications
are required in the selected field test locales.
3. Installation of test furnaces by qualified local residential heat-
ing contractors will ensure conformance to local building codes and
maintenance of good practices. Contractors have been selected and
arrangements made for them to provide periodic routine inspections
and emergency service as required.
4. Periodic measurements of furnace performance and air pollutant
emissions can best be made during monthly visits of a Rocketdyne
engineer to each field test installation. He will use a mobile lab-
oratory and recording data loggers in this monitoring effort.
From investigation of the capability of the integrated furnace to function
properly with fuels other than No. 2 fuel oil, it was concluded that:
1. Alternate gaseous and liquid fuels for residential heating most
likely to be of interest in the near future are natural gas and
methanol, respectively.
2. Substitution of natural gas for No. 2 fuel oil in the integrated
furnace requires more than a simple replacement of the power
burner's oil tube/spray nozzle with a gas/air mixing tube. There-
fore, a commercially available inshot conversion gas burner was
used for a limited experimental investigation.
3. At heating rates with natural gas equivalent to the design range
for No. 2 fuel oil, the integrated furnace produces higher emis-
sions of CO and UHC and lower smoke than it does with distillate
oil. This was interpreted as being due to extraction of excessive
heat from the flame zone and/or to the firing rate being too high
for the combustion chamber volume.
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4. NOX emissions were lower with natural gas than with oil in the tests
performed, but it is anticipated that they would become essentially
the same if the firebox design were altered to lower the carbonace-
ous emissions from natural gas.
5. Substitution of methanol for No. 2 fuel oil in the integrated fur-
nace is simple and straightforward. In the laboratory tests, only
the burner spray nozzles were changed.
6. At methanol heating rates equivalent to the design range for No. 2
fuel oil, the integrated furnace produces very low emissions of
smoke, UHC, and NOX but, similar to the experience with natural gas,
produces inordinately high CO emissions. The CO emissions were re-
duced by increasing firing rate, so their level is attributed to
extraction of somewhat too much heat from the primary flame zone.
7. If the air cooling of the firebox were reoptimized for methanol, the
emissions of all measured air pollutants from the integrated furnace
would be substantially lower than with No. 2 fuel oil.
8. For equal operating stoichiometric conditions and noncondensing
flue exhaust temperatures, the maximum achievable thermal effici-
encies with natural gas and methanol are approximately 2 and 6%
lower, respectively, than with No. 2 fuel oil.
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SECTION 3
RECOMMENDATIONS
In view of the results and conclusions of the Phase I studies, it is recom-
mended that:
1. The Phase II field test investigation should be undertaken immedi-
ately using the plan developed during Phase I with some slight
modifications.
2. A total of six integrated furnaces should be constructed for the
field test investigation. They should be built in the Rocketdyne
laboratory using the same techniques for custom modifying commer-
cially procured furnaces as were used in constructing the first two
integrated furnaces in Phase I. To the extent possible, the units
should be identical.
3. Rocketdyne's laboratory instrumentation for measuring emissions
should be employed in a mobile laboratory configuration for monitor-
ing the emission characteristics of the field test furnaces.
4. Depending upon the outcome of the field testing, Phase II analyses
should include (a) suggested means to solve outstanding technical
questions, e.g., by modifying component designs, operating condi-
tions, control circuits, safety features, etc.; (b) consideration
of alternate construction practices, particularly with respect to
the firebox; and (c) engineering estimates of the unit costs of in-
tegrated furnaces, produced both in limited (R&D) quantities and in
commercial volumes. Also, Phase II documentation should address
service and maintainence requirements experienced and anticipated.
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SECTION 4
SUMMARY OF THE PROTOTYPE FURNACE INVESTIGATION
The experimental furnace unit tested previously (Ref. 3 and 4) has been called
a "prototype optimum furnace." For clarity in this report, that earlier test
unit will be designated the "prototype furnace" and the further optimized unit
derived from it will be referred to as the "integrated furnace." In this sec-
tion are given brief descriptions of the prototype furnace and the laboratory
facility in which it was tested, followed by a summarization of its emissions
and efficiency performance.
PROTOTYPE FURNACE DESCRIPTION
The prototype test unit was based on modifying or replacing several specific
components in a comercially available warm-air oil furnace of contemparary
design*. The prototype furnace and the advanced technology modifications
made to achieve it are illustrated in Fig. 1. The central line drawing is an
interior side view of the furnace; the front is on the left-hand side. Each
of the photographs surrounding the drawing illustrates a modification made
and an arrow denotes its location in the furnace assembly.
The optimum burner head is illustrated alone although, in actuality, the fur-
nace's entire burner was replaced with the optimum burner that had been
tested extensively before, rather than replacing only the head. The combus-
tion air fan in the replacement burner was also fitted with a quiet stator
plate to prevent coupling of combustion air flow pulsations to combustion in
the chamber.
The unit's original firebox, a rather typical 0.249 m (9.75 inch) inside-
diameter refractory-fiber-lined design, was replaced by a larger 0.303 m
(12 inch) inside-diameter, uninsulated, air-cooled firebox. Its outside sur-
face was heavily finned to ensure adequate heat extraction from the flame
zone, a key contributor to the reduction of NOX emissions. The machined and
welded mild steel prototype firebox was more massive by about '50 kg (110 Ibm),
than its predecessor, and thus constituted a substantial heat sink. Built as
an experimental tool, the firebox was intentionally overdesigned in the in-
terests of maintaining wall temperatures as nearly uniform as possible and
retaining high wall temperatures during standby.
*A Lennox Model 011-140 furnace, supplied by Lennox Industries, Inc., was
utilized.
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STANDBY DRAFT CONTROL
QUIET PULSE-FREE STATOR
OPTIMUM BURNER HEAD
SEALED COMBUSTION AIR SYSTEM
COMBUSTION AIR FILTER
AIR COOLED FINNED FIREBOX
Figure 1. Prototype furnace
modified components
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Two related modifications were concerned with the combustion air supply.
First, combustion air was admitted to the furnace through a "sealed air" sup-
ply system, adapted from Ref. 5. Simply stated, this means that combustion
air, together with air drawn into the flue through a barometric pressure con-
trol damper, is brought in from outdoors rather than consuming heated (and
perhaps humidified) air from within the residence. Pollutant emissions usu-
ally are not influenced by this change, but fuel consumption may be reduced
by 5 to 10% or more (Ref. 5). Second, a separate filter was provided for the
combustion air so that the burner could be tuned to operate with close to
minimum (~15%)excess air without accumulating lint, hair, etc., on the burner
air passages, fan flades, or head, which could force the burner into a smoky
and/or high CO condition.
The combustion air inlet to the burner was fitted with a weighted damper
which closed automatically when the burner was turned off. It was designed
to eliminate the loss of heat up the flue caused by draft air flowing through
the furnace during standby. Fuel savings effected by this device will prob-
ably average between 2 and 3%. This device also included a separate butter-
fly damper whose position controlled the flow of combustion air.
Minor modifications also were made to a few other furnace components.
Louvers in the burner vestible closure panels were covered to seal the vesti-
bule and make it part of the sealed air system. Inside the cabinet, some
minor structural reinforcement was added to support the heavier firebox, and
flat, vertical-panel baffles were added in the warm-air passages to force the
warm air to flow over the finned firebox. Otherwise, the warm-air blower and
filter, the compact heat exchanger, the furnace cabinet, and all electrical
circuits and controls were left unchanged from the original stock furnace.
LABORATORY FACILITY
Performance of the prototype furnace was evaluated in an outdoor laboratory
facility having provisions for measurement of pollutant emissions, operational
characteristics, and thermal efficiency. Figure 2 is a schematic of the fur-
nace evaluation system; it shows the installation of gas- and air-flow duct-
ing and a variety of instrumentation. Basic thermal performance measurement
techniques conformed with requirements of ANSI Z91.1-1972 (Ref. 6). Other
instrumentation was added to provide (1) enlarged understanding of furnace
behavior and (2) data for calculating cycle-averaged thermal efficiency.
Constituents in the flue gases were measured by continuously withdrawing a
gas sample from the center of the flue, at the location denoted in Fig. 2,
and passing it through an analysis train. The analytical system provided for
manual spot samples for smoke and for continuous analyses for 02, C02, CO,
NOX and unburned hydrocarbons (UHC) species remaining in the dry gases after
their passage through condensible traps, filters, and driers. Detailed in-
formation of the setup and operation of the train, instruments used and their
ranges, data processing, etc., has been given previously in Ref. 1 through 3.
The furnace flue thermal losses were determined by making measurements to
support flue gas heat balances. The specific heat properties can be deter-
mined from the composition of the flue gas. This in combination with the net
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SEALED AIR
SYSTEM
INSULATION
COMBUSTION AND
BAROMETRIC CONTROL
AIR INLET
3X3 THERMOCOUPLE
MATRIX -
ADJUSTABLE
LOUVERS
•0
•fr
•0-
4-THERMOCOUPLE, FREE AIR
0 THERMOCOUPLE, ATTACHED
9 PRESSURE TAP
FLOW
STRAIGHTENER
Ai
C=>
AIR
INLET
SMOKE
GAS SAMPLE
DRAFT
FLUE TEMPERATURE
MATRIX OF 6
THERMOCOUPLES
0.45m X 0.45m
DUCT
FRONT VIEW
SIDE VIEW
Figure 2. Schematic of the furnace performance evaluation system
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flue gas temperature allows the calculation of the heat content of the flue
gases relative to the heat input resulting in a thermal efficiency value.
The realtionship of flue gas composition and net temperature to thermal effi-
ciency has been tabulated in Ref. 6. The flue gas exhaust temperature was
measured in an insulated flue pipe with a thermocouple located 0.46 m (18
inches) above the centerline of the heat exchanger exit. Flue draft, gas
composition, and smoke measurements were taken at successive 0.0317 m (1.25
inch) increments downstream of the thermocouple, respectively.
Steady-stage thermal efficiencies were derived from the steady-state flue gas
temperatures and C02 concentrations (Ref. 6). During cyclical operation in
which steady state was not reached, values for those parameters just prior to
burner cutoff were used in the same manner to get approximations of steady-
state efficiencies. Burner firing times of 10 minutes gave such pseudo-
steady-state efficiencies that were indistinguishable from those derived from
steady-state measurements; those calculated from 4-minute burner firing time
data were approximately 1% higher than the steady-state efficiencies due to
heat being absorbed by the cool furnace components resulting in a lower flue
gas temperature.
Data were also measured to support calculation of cycle-averaged efficiencies.
However, the variable ambient-air temperature in the outdoor facility intro-
duced considerable scatter in the data (Ref. 3). Indicated differences be-
tween the mean steady-state and mean cycle-averaged efficiencies were smaller
than that scatter, so steady-state was used as the main basis for comparison.
PROTOTYPE FURNACE RESULTS
Pollutant Emissions
Prototype furnace flue gas concentrations of nitric oxide are plotted versus
stoichiometric ratio in Fig. 3. A shaded region near the middle of the graph
indicates that a large majority of existing residential oil furnaces release
between 1.3 and 2.2 g NO/kg fuel burned. An estimated existing furnace aver-
age of 1.8 g NO/kg fuel may be used for evaluating the potential impact of
applying candidate NO reduction techniques.
Measured NO emissions from the stock furnace, before it was converted to the
low-emission prototype furnace, fell on the high side and above that typical
range; at a nominal 50% excess air operating point, it produced 2.2 g NO/kg
fuel burned. Measured NO emissions from the prototype furnace were much
lower, falling between 0.5 and 0.75 g NO/kg fuel over the stoichiometric'
ratio range of interest. Tuned to the intended normal operating condition
with only 15% excess air, the unit produced 0.63 g NO/kg. That corresponds
to reductions of about 72 and 65%, respectively, from NOX emissions produced
by the stoclv furnace (at its nominal operating point) and by the average
estimated for all existing installed units.
Carbonaceous emissions from the prototype furnace unit also were acceptably
low at those conditions, as indicated by the lower than No. 1 smoke. A com-
parison of values in Table 1 shows that CO and hydrocarbon emission levels
11
-------
3.0
o
uj
z
c
3
i
x
O
o
pc
I-
(MOKE > NO 1
ORIGINAL
STOCK FURNACE
SMOKE < NO 1
' N
APPROXIMATELY (0 PERCENT OF EXISTING
OIL FURNACES PRODUCE CYCLE AVERAGED
. NO. EMISSIONS IN THIS RANGE I'l
1L\ i\\V
- PROTOTYPE FURNACE WITH
RETENTION HEAD BURNER
- PROTOTYPE LOW EMISSION
FURNACE
-TARGET LEVEL
_L
15
2.0
STOICHIOMETRIC RATIO
Figure 3. Cycle-Averaged NO Emissions
from the prototype furnace were somewhat higher than those measured for the
stock furnace, but were quite comparable with the average tuned values meas-
ured in the field survey of Ref. 7.
TABLE 1. COMPARISON OF POLLUTANT EMISSIONS
FROM VARIOUS RESIDENTIAL FURNACES
Stoichiometric ratio
Carbon monoxide, g/kg fuel
Unburned hydrocarbons,
Tuned
averages
from Ref. 7
1.85
0.6
0.07
Original
stock
furnace
1.50
0.27
0.015
Prototype
furnace
1.15
0.55
0.055
g/kg fuel
Smoke, Bacharach number
Nitric oxide, g/kg fuel
1.3
1.8
0
2.2
0.63
Efficiencies
Pseudo-steady-state efficiencies for the prototype furnace are compared with
those for its stock predecessor in Fig. 4 by superimposing values calculated
from fourth-minute data in cyclical runs on an efficiency decrement plot.
The performance curve for the original stock furnace fell well below (i.e.,
higher efficiencies) the shaded band representative of a large majority of
existing installed residential heating units. The stock unit could be tuned
to a moderately low 50% excess air nominal operating condition where its net
12
-------
flue gas temperature averaged only 180 C (325 F). The resultant steady-state
gross thermal efficiency was 82.5% (i.e., the stock furnace was among the
higher-performing units in the existing population).
u
o
tc.
O
cc
UJ
X
UJ
CC
u
UJ
a
35
30
20
15
10
— SMOKE s NO 1
SMOKE i NO 1
Xd OPERATING POINT
APPROXIMATELY 80PERCENT OF.
EXISTING FURNACES OPERATE
IN THIS ZONE
_ 1.0
1.2
STOICHIOMETRIC RATIO
i _ I _ I-
2.0 2.2
J_
15
14
13 12 10 9 8 7
VOLUME PERCENT C02 (DRY BASIS) IN FLUE GAS
Figure 4. Pseudo-steady-state thermal efficiencies
65
70
ll
t/)(J
QS?
UJ CN
I"
85
90
Thermal efficiency levels achieved by the prototype furnace were qualitatively
the same as those of the stock furnace. However, as is evident in Fig. 4,
flue gases leaving the prototype unit were 40 to 55 C (75 to 100 F) hotter
than those from the stock furnace, and the efficiency decrement due to the
higher net flue gas temperature was offset by operating the prototype unit at
substantially lower stoichiometric ratio. This apparently anomalous behavior
was believed to be caused by warm-air jets outside of the firebox bypassing
some of the main heat exchanger, a condition which was thought to be rela-
tively easy to correct.
The 82 to 83% pseudo-steady-state thermal efficiency exhibited by the proto-
type furnace was close to the maximum achievable in noncondensing flue gas
residential systems. Taken alone, this is not unique, since comparable effi-
ciencies are attained by some current commercially available units (as exemp-
lified by the stock furnace that was converted into the prototype). What is
unique and important about it is the demonstration that near-maximum steady-
state efficiency and near-minimum NOX emissions can be obtained simultaneously.
13
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SECTION 5
INTEGRATED FURNACE DESIGN OPTIMIZATION
The prototype furnace test results confirmed the feasibility of applying the
several newly developed, low-emission oil burner and firebox design criteria
to residential space heating equipment. When tested in the laboratory, the
experimental prototype unit came very close to satisfying all of the pollut-
ant emission and efficiency objectives for which it was designed. Operation-
ally, its behavior was quite comparable with current commercially available
furnaces. A 500-hour duration test, equivalent to about one-tenth of an aver-
age heating season, indicated that the unit might serve through an entire
winter heating season without requiring substantial maintenance and without
exhibiting appreciable shifts in operating conditions or pollutant emission
levels. Before undertaking such a next logical step in the proof-of-concept
demonstration of the furnace design criteria, however, it was appropriate to
further improve some features of the prototype unit.
MODIFICATIONSFOR THE INTEGRATED FURNACE
Optimum Burner
The standby draft control device for the combustion air inlet to the burner
was redesigned, as illustrated in Fig. 5. The butterfly valve was removed
and air-flow control was accomplished by providing a mechanical stop to limit
the opening of the weighted flap damper. A microswitch was incorporated in
the stop to provide a positive electrical indication that the draft flap opens
when the burner is turned on; the burner control circuitry was redesigned to
take advantage of this safety feature (Fig. 6).
A commercially available (Pioneer Products Model RT-3450) centrifugal clutch
was inserted in the burner's drive shaft for the fuel pump. The reason was
to give a quicker cutoff of fuel flow through the oil nozzle, to better elim-
inate post-firing dribble.
The burner's blast tube was shortened from 0.191 m (7-1/2 inches) to 0.152 m
(6 inches) to prevent the back of the burner from extending beyond the plane
of the burner vestibule door.
Finned. Air-Cooled Firebox
The fabricated steel firebox, with its large external steel fins welded to a
0.64 cm (0.25 inch) thick steel shell was inordinately expensive to make,
heavier than desirable, and extracted more than the designed-for quantity of
heat from the flame zone. Therefore, it was replaced with a lighter-weight,
14
-------
NOTE: DIMENSIONS IN METERS
• MR INLET PORT
O.WVT-
MR FLOW
ADJUSTMENT
PLME
SFuFETY CIRCUIT
NAICROSW1TCH
FUEL OIL LINE
COVER PLATE
FUEL PUMP
MOUNTING
HOLE
K-
TOP VIEW
GftSKET
0.5523
FRONT VIEW
D.036G •
SIDE VIEW
Figure 5. Combustion air inlet, draft-flap assembly for the
optimum low-emission burner
15
-------
EXISTING
CM). CELL
AIR INLET t
DRRFT FLPkP L
NIICROSWTCtt
13 kit
SHUNT
STftRT SHUNT
N.C.%LKf
11SV.A.C.
WHITE-RODGiERS
TYPE tt6-455
PRINIRRY CONTROL
IT IRE EXE"
[
115m.'
BURNER
POWER
Figure 6. Electrical circuit schematic showing the inlet draft flap
microswitch supplement to the flame detector circuit
16
-------
cast-formed combustion chamber. Serious consideration was given to making a
cast aluminum firebox (refer to Appendix A). Because aluminum has a high
coefficient of thermal expansion and there is a substantial temperature grad-
ient over the length of the cooling fins, tensile stresses approaching yield
strength limit were calculated at the roots of the fins and at the firebox
heat-exchanger joint,which would result in relatively short cyclical fatigue
life. In principle, yield conditions could be avoided by maintaining low-
wall temperatures but, even then, cycle-fatigue failure was predicted to lead
to an unacceptably short firebox lifetime of 3 to 5 years. Therefore, cast
iron was selected as the firebox construction material.
A photograph of the cast-iron firebox is shown in Fig. 7, and more dimensional
detail can be seen in the two-view line drawing in Fig. 8. The internal di-
mensions and burner insertion port duplicate those of the fabricated steel
combustor; otherwise, the designs are quite different. To facilitate welding
the stock fabricated steel heat exchanger to the cast-iron firebox, a rolled
steel ring is cast integrally into the wall of the firebox discharge opening.
This provides a positively-sealed joint as well as a much smoother surface for
the external air to flow over. All of the cast external fins are shorter than
were the fabricated ones, and both their heights and spacings are graduated to
promote more-nearly uniform wall temperatures. The shorter fins were designed
to extract a smaller fraction of the overall heat transfer.from the firebox;
che cast wall temperatures were expected to average 56 C (100 F) higher than
those of the former fabricated steel firebox. The cast firebox, together with
its support legs and burner mounting plate, has a mass of 34 kg (75 Ibm).
Warm-Air Coolant Distribution
The vertical, sheet metal baffle panels positioned close to the fin tips on
each side of the prototype furnace's firebox were reshaped to improve the air-
flow distribution to the outside of the main heat exchanger. The baffles were
bent slightly at about the midsection of the firebox to begin a gradual flar-
ing from the constricted cross section to the full heat exchanger cross sec-
tion. The location of each baffle remained the same; however, since the fins
were shortened, this placed them about 0.064 m (2.5 inches) from the nearest
fin tip, as opposed to nearly touching in the prototype furnace. Also, new
baffle panels were added adjacent to the outside panels of the heat exchanger
section. This was done to reduce the flow gaps between the heat exchanger
and the wall by 0.025 m (1.0 inch), thereby reducing bypass (i.e., no heat
transfer) air flow. These changes were made to restore the coolant air to
the outer sections of the heat exchanger and, thus, to improve the overall
heat transfer of the furnace.
LABORATORY TESTS OF THE PROTOTYPE AND
FIRST INTEGRATED FURNACES
The first specimen of the integrated furnace was built by converting the pro-
totype furnace via the foregoing modifications. It was tested in the same
laboratory facility and with the same procedures as was the prototype unit.
A basic test matrix provided for measurement of pollutant emissions and per-
formance as functions of burner firing rate, overall stoichiometric ratio,
combustion air supply temperature, firebox draft, and warm-air flowrate. The
17
-------
50P34-1/28/77-S1F
Figure 7. Cast-formed air-cooled combustion chamber
18
-------
VO
12 OIA
(CONSTANT)
FIN HEIGHT CONSTANT
OVER LENGTH OF FIN
Figure 8. Drawing of the cast iron finned combustor for the
integrated furnace system
-------
test plan also allowed for retesting in the event that one or more components
needed further refinements. Discussion of the extent to which this option
was needed is included with the description of test results, below.
Hot-firings of the first integrated furnace were preceded by some exploratory
tests of the prototype furnace, to obtain data to support firebox design, and
some cold-flow tests of the burner, to measure the effects on the combustion
air fan characteristics of the several complications added to the stock*
burner's combustion air circuit.
Laboratory Test Results
Burner Blower Characteristics. The combustion air blower's characteristics
were measured to establish the operational limits of the combustion air sys-
tem. Tests were made with the air flow throttled either at the air inlet or
at the exit. This was done by mounting the burner inside or outside, respec-
tively, of a large sealed compartment and measuring the compartment pressure
and air flow into or out of it. A calibrated laminar-flow 'element was used
for accurate measurement of air flows.
Throttled outlet characteristics are shown in Fig. 9. The uppermost curves
show that the presence of the quiet stator has very little effect on the
blower's basic throughput characteristic. Successively lower curves show how
the achievable air flow is impacted by adding, in sequence, the inlet draft
flap assembly, a static disc within the blast tube, and the optimum head to
complete the burner assembly. Dashed lines indicating pressure drops of the
head, static disc, and draft flap were obtained by subtraction of appropriate
characteristic curves. The nominal design operating point, with a firing rate
of 1.05 ml/s (1.00 gph) and a stoichiometric ratio of 1.15, is indicated by
an arrow at 0.0125 m^/s (26.5 scfm). To achieve that flowrate without throt-
tling the exit, the firebox would have to be pressurized to about 60 N/m?
(1/4-inch water column). The usual residential furnace practice, however, is
to throttle the inlet to the blower, rather than pressurizing the firebox or
throttling the exit.
Effects of throttling the blower inlet (i.e., limiting the draft flap opening)
are shown in Fig. 10, along with the effects of imposing a negative (suction)
pressure condition on the air supplied to the inlet. The latter condition is
encountered sometimes in conventional furnace practice by operating a furnace
in a fairly leak-tight room or house, so that the burner blower reduces the
pressure in the furnace enclosure. In the integrated furnace, pressure in
the sealed burner vestibule also will be below ambient outdoor pressure by
the pressure drop of the air supply system.
The throttled inlet characteristic curves show that, if the burner inlet is
at sea level pressure, the nominal design conditions can be achieved with the
draft flap only one-eighth open; opening it further should allow tuning for
stoichiometric ratios (SR) from 1.15 to about 1.35. Reducing the inlet pres-
sure exerts a linear reduction effect on the achievable flowrate; again, the
*The R. W. Beckett Co.'s Model AF burner was the stock unit underlying the
optimum burner.
20
-------
350
300
U
4 250
U
200
s
I-
Ul
t. 100
50
0 010 0 020
AIR FLOWRATE. STD m3/«
0030
Figure 9. Throttled exit air-flow characteristics
ui
3
(7
N
U
ce
LU
E
EL
@DESIGN FLOWRATE 1 OS ml/iOIL FLOW
OSR -1 15
•100
-50
0010
0 020 0.030
AIR FLOWRATE. STD. m3/>
Figure 10. Inlet throttling air-flow characteristics
21
-------
margin of adjustability from the design point would be eliminated by about
60 N/m^ (1/4-inch water column) suction at the blower inlet. This condition
is not likely to occur unless the combustion air filter is allowed to become
very dirty.
What the burner requires is a given weight flowrate of air for a given firing
rate and stoichiometric ratio. What the blower supplies is a given volumetric
flowrate of air at its local (nominally inlet) conditions. If the furnace is
installed at a high altitude, a greater volume must be delivered to obtain
the required weight of air. The optimum burner, fired at 1.05 ml/s (1.0 gph)
and a 1.15 SR, would have a fully open inlet and no margin of adjustability
at about 1500 meters (4900 feet) elevation. In practice, the furnace would
have to be downrated to a lower firing rate or supplied with a higher-capacity
blower to allow servicemen at those altitudes some margin of tuning control.
Prototype Furnace Tests. Before the prototype furnace was converted to the
first integrated furnace configuration, it was tested to provide some addi-
tional data to support the design of certain components for the conversion.
Tests to Support Firebox Design. The first test series was directed to-
ward studying the effects of a hotter combustor wall (—340 C on the rear side)
upon pollutant emissions. The higher wall temperatures were attained by sim-
ply throttling back on the warm-air, furnace coolant flow. Compared with
data from earlier tests of the prototype furnace (Ref. 3), operation with
hotter combustor walls tended to produce a little more smoke (~Ho. 1 Bacharach
at 20% excess air), slightly higher (approximately 10 to 15%)nitric oxide, and
substantially increased emissions of carbon monoxide. While smoke and NO
emissions varied only slightly with variations in the elevated wall tempera-
ture level, the carbon monoxide concentrations began to increase sharply at
wall temperatues above 340 C (650 F), going from~0.45 g/kg to as high as
1.60 g/kg at 370 C (700 F).
To gain better quantification of maximum permissible firebox wall tempera-
ures, the prototype furnace was partially disassembled to install sheet as-
bestos envelopes over the outer extremities of its fins, as a simulation of
the 0.025 m (1 inch) fin height than being considered for the cast iron fire-
box. Additionally, 10 more thermocouples were attached to the outside of the
firebox, to give a more complete picture of the distribution of temperatures
over the firebox walls and fins.
While the furnace was being worked on, large sheets of iron oxide scale were
found in the heat exchanger panels; that scale may have contributed to the
higher CO readings. The heat exchanger was cleaned.
Firebox temperature distributions measured during steady-state operation of
the modified prototype furnace are illustrated in Fig. 11, both at the nominal
warm-air flowrate of 0.5663 m3/s (1200 cfm) and also at 0.7079 m3/s (1500 cfm),
The maximum temperature measured on the combustor was 427 C (800 F), which
is safely below the Underwriters' Laboratories (UL) maximum temperature limi-
tation of ~540 C (~1000 F) for cast iron. As can be seen in Fig. 11, the
nearly uniform fin arrangement produced a nonuniform shell temperature
22
-------
distribution, with the lowest temperature on the lower front section, and
temperatures monotonically increasing toward the upper rear section.
The emissions of carbonaceous pollutants with the hotter, asbestos-enveloped
finned combustor were not appreciably higher than those reported in Ref. 3
for the prototype furnace*, and the nitric oxide emissions also appeared to
remain approximately the same at—0.70 g/kg steady-state (~0.65 g/kg cyclic
estimate).
The asbestos covers were left on the fins of the prototype combustor as it
then more closely simulated the cast iron combustor design. The remaining
hot-fire experiments conducted before the installation of the cast-formed
combustor, which are discussed in the next subsection, were made with this
simulated "short fin" combustor configuration.
Tests to Evaluate Ignition. The fuel pump on the optimum burner was
coupled to the drive motor throug a simple centrifugal clutch, which produces
"cleaner" starts and stops of the oil flow, i.e., reduced oil dribbling. The
clutch characteristics provide a slight fuel lag at burner startup. It is
sometimes observed that a slight fuel lead instead of a fuel lag startup can
give improved ignition. To investigate this possibility, the fuel lag was
eliminated by removal of the clutch drive from the optimum burner. Experi-
mental data from these tests are given in Appendix B. Audible delayed-igni-
tion starts were noted with this configuration and, although Runs 29 to 33
(Appendix B) show little differences in the ^-minute-averaged emission con-
centrations, inspection of the CO and UHC strip charts showed larger start
spikes. The recommendation of a fuel-lead start may be valid for burners
operating at SR > 1.5; however, for the optimum burner, which operates much
closer to stoichiometric conditions, a fuel lag start appears to be more suit-
able. The clutch drive assembly was reinstalled in the optimum burner, and
no further fuel timing experiments were conducted.
Tests of the First Integrated Furnace. Following conversion of the prototype
furnace to the first integrated furnace configuration, several series of ex-
periments were made to delineate its performance and emissions characteristics.
The data obtained are given in Appendix C.
Performance of the Cast-iron Firebox. Monitoring of test conditions
during the firings and close visual inspection after firing revealed no
apparent metallurgical or thermal problems with the cast-formed combustor
configuration. Figure 12 is a surface temperature profile on the cast-formed
combustor in steady-state operation at design conditions. As can be seen
from the data recorded there, the lateral temperature distribution on the
combustor wall is farily uniform from front to back, which was the objective
of providing circumferentially varying fin heights in the side-fired, cast-
formed combustor design. Comparison with the temperatures obtained with the
constant-height, short-fin simulation, using the fabricated steel combustor
(Fig. 11), shows that the cast combustor has a significantly more uniform
lateral distribution. There remains a substantial longitudinal temperature
gradient, but this is typical of a cocurrent-flow heat exchanger system and
no problems are expected to result from this gradient.
^Although a No. 1 to 1-1/2 Bacharach smoke reading was obtained, subsequent
experiments showed this to be an oil spray nozzle problem.
23
-------
Heat Exchanger Entrance
Burner
Insertion
Port
266°C
(252)
(316)
Asbestos
/Cover
(227)
= 299
(277)
399 >T -=268
(377) \ (249)
338
(316
'20
276/< -5(188
Rear Fin
(171)
Asbestos
Cover
W. = 0.5663 m3/s
W i d * •«
S.R.
(0.7079 mj/s)
1.16
Figure 11. Steady-state temperature distribution on the finned prototype
combustion with 0.025 M exposed fin length
Heat Exchanger Entrance
Burner
Insertion
Port
TNET F.G. ' 250°C
S.R.S 1.17
'AIR
V 76 0.566 m-
wa rm
air
Figure 12. Steady-state surface temperature distribution on the cast-
formed combustor installed in.the integrated furnace system
24
-------
Optimum Burner Head Modification. Some smokiness (No. 1 to No. 2 Bach-
arach) was noted during the initial tests at design conditions with the newly
assembled integrated furnace. A switch back to the research optimum head
revealed that the sheet metal optimum head, and not the new combustor design,
was the source of the problem. Further investigations revealed that air leak-
age from the peripheral relief formed by the base folds of each vane was the
specific cause. Although it had been concluded from previous testing (Ref. 8)
that this air leakage was of only minor consequence, two differences were
found between those earlier burner heads and the optimum burner heads made for
the integrated furnace. First, careful inspection of the new sheet metal
optimum heads revealed that the swirl vanes were folded on a smaller basic
diameter (0.0991 m diameter specified, 0.0953 m diameter actual) than the
previous heads, thereby resulting in larger peripheral openings, i.e., greater
leakage. Second, the optimum burner now includes a large static disc which
forces the air flow to the outer perimeter of the blast tube, possibly in-
creasing the influence of these peripheral openings on the air/oil mixing
process. A simple peripheral retainer ring was fabricated that: (1) fits
over the perimeter of the optimum head choke plate, thereby covering the open-
ings, and is welded to the choke plate, (2) folds over the edge of the choke
plate, and (3) slips over the blast tube. This sheet metal optimum head/re-
tainer ring combination eliminated the smoke emissions problem.
Thermal Efficiency. The thermal efficiency (based on flue gas measure-
ments) of the integrated furnace system was found to be the same as that of
the original prototype furance. The net flue gas temperature remained at
about 225 C (460 F) steady state, 233 C (420 F) fourth minute at 12.7 - 13.0%
CC>2 (SR = 1.15 to 1.18). Although the new, cast-iron combustor has less fin
surface area than the fabricated steel predecessor, it was anticipated that
the improved warm-air flow induced by the flangeless combustor and new baffle
arrangement would result in an increase in thermal efficiency. Since the
performance of the unit remained the same, a study was initiated to investi-
gate possible improvements. The effort was first concentrated on improving
the heat transfer to the warm-air flow in the combustor section. A total of
eight different combustor baffle configuations was tested with no significant
change in net flue gas temperatures, even though radical changes in the warm-
air flow characteristics were effected. Therefore, the effort was redirected
toward investigating the combustion gas-side heat transfer process.
A 3 m(10 foot) long flue pipe extension was added to the test installation to
investigate the effect of firebox draft (negative static pressure) on heat
transfer. The draft was increased from approximately 6.2 N/m2 (0.025 inch of
water column) to a maximum of 17.4 N/m? (0.07 inch) with a resultant 5 C de-
crease in flue gas temperature, i.e., a slight (-0.1%) increase in perform-
ance, but with a 1.5 Bacharach smoke reading. The path of the combustion
gases was then altered by installing an internal baffle immediately over the
combustor, oriented 45 degrees from vertical toward the front of the furnace
unit. This resulted in a No. 2 Bacharach smoke reading, as did the subsequent
installation of a 0.18 m (7.0 inches) diameter choke ring over the combustor;
neither change affected the flue gas temperature appreciably.
To help isolate the cause of the efficiency difference between the prototype
and integrated furnaces and the original Lennox unit, the configuration of the
25
-------
integrated test furnace was altered in the direction of the Lennox configura-
tion. Pyroflex insulation similar in shape to the Lennox combustor section
was installed inside the finned cast-iron combustor. The net steady-state
flue gas temperature increased dramatically to —292 C (—525 F), reducing
steady-state thermal efficiency by almost 2%. To further the investigation
toward the original configuration, the original Lennox burner was installed in
this simulated Lennox combustor and a still higher, 299 C (538 F), net steady-
state flue gas temperature was recorded. This nearly total reversion to the
Lennox configuration with a contradictory higher flue gas temperature raised
some questions as to whether degradation of the Lennox heat exchanger might be
the primary cause of the thermal efficiency differences among the furnace
configurations.
Along thermocouple was then inserted in the exit manifold of the heat ex-
changer, and gas temperatures were measured at three points very close to the
exit of each of the six rectangular heat exchanger panels. Figure 13 is a
schematic of the cross section of the exit manifold, with the measured combus-
tion gas temperatures at 17 of the 18 locations. The lower temperatures meas-
ured at the lower Icoations for the inner panels implied lower combustion gas
flowrate in the inner panels. However, the simple arithmetic average of the
17 temperature readings was 530 F, which is within 20 F of the measured flue
gas temperature, implying nearly equal flowrates at all locations.
An attempt was made to correct the nonuniform temperature profile of the flue
gases leaving the main heat exchanger and, thereby, to maximize heat transfer.
Two flow control vanes, extending the full vertical length and adjustable to
block nearly the full width, were installed in the inlets to the two outermost
heat exchanger panels. Figure 14 shows the temperatures measured during
steady state with the two vanes installed, but in their full open positions.
The minimum partial obstruction caused by only the edgewise cross section of
the vanes resulted in a much more nearly uniform temperature distribution.
However, no significant improvement in net flue gas (FG) temperature (i.e.,
heat transfer) was noted (steady state TFG net = 254 C at SR =r 1.18). The
vanes were then turned 30 degrees inward toward the flow, and no significant
change in net flue gas temperature was observed. The vanes were then turned
to 90 degrees (maximum obstruction), and a 10 C increase in net flue gas tem-
perature resulted. Thus, it appeared that achieving a nearly uniform temper-
ature distribution in the heat exchanger panels would have a very small effect
upon thermal efficiency, so no further experiments were conducted with the in-
ternal vanes and they were removed.
A series of experiments was conducted to study the effect of internal radiant
heat transfer upon the overall furnace thermal efficiency. The surfaces of
the new warm-air baffles are highly reflective (galvanized zinc coated) and
questions were raised as to the suppression of radiation heat transfer from
both the finned combustor and the heat exchanger sections. The baffle sur-
faces were painted flat black with a high-temperature paint. The initial
firings with the blackened baffles seemed to show a 20 C reduction in net flue
gas temperature; however, subsequent firings showed no such improvement in the
steady-state net flue gas temperature; it remained at about 255 C. The outer
surfaces of the heat exchanger section were then painted black, and again no
significant change in overall heat transfer resulted. With such drastic
26
-------
M
TNET F.G. " 256°C
S.R. = 1.17
0.076
0.076
f
0.076
0.076
JL JL- -i
41
*
8
381
fc
(66
:68
A
PQ
33
.%
s/
1 u^
r~ T~ nr
P-~~
NC
Te
D!
<•
Temperatures, C
Dimensions, m
^-^»—
J_ JL J_
33:
N
24
121
V
135
flf
57
82
TT
,
2
«
82
*
66
99
nr
Figure 13. Combustion gas temperatures at exits of heat exchanger panels
-------
N)
00
TNET' F e = 25*«C (Steady-state)
NET, F.G. (256oc).
S.R. - 1.17
T
0.076
0.076
f
0.076
f
0.076
.A. J. -J
31!
X
25}
*
33*
143
X
27!
S'
r r
32
X
288
Z8'
^
hr
NOTE;
Temperatures, °C
Dimensions, m
JSf
Figure 14. Combustion gas temperatures at exits of heat exchanger panels with full-length
control vanes installed in the two outer panels
-------
changes (reflectivity changed from~0.9 to~0.3) resulting in no measurable
effect, it is apparent that the contribution of radiant heat transfer to the
overall steady-state (warm-air fan on) furnace heat transfer is small.
One remaining possible explanation for the inability to approach the thermal
efficiency of the former stock furnace was that the heat exchanger section had
degraded since its two-step transformation into the integrated furnace. To
investigate this possibility, one of two recently acquired Lennox units was
set up for a long-term, hot-firing experiment. The new Lennox unit, with a
new flame-cone-type retention head, operated smoke-free at a lower stoichio-
metric ratio (SR ~1.25) than did the original Lennox burner (SR ~1.45).
However, this new unit's corresponding net flue gas temperatures were both
higher than those of the original stock Lennox and higher than those being
recorded with the first integrated furnace. The new burner head was the only
notable difference between the old and the new Lennox furnace units, so the
new burner was replaced with the original Lennox burner unit in an attempt to
recover the low flue gas temperatuers obtained in the previous stock Lennox
furnace tests.
The steady-state results showed a slight decrease in net flue gas temperature
but a notable increase in nitric oxide emissions from 1.83 to 2.11 g/kg at
SR ~1.45 (Runs 38 and 43, Appendix C). (The oil flowrate was approximately
10% low, so the oil nozzle was replaced with another 1.0-70°-A nozzle for Runs
49 to 53. This new nozzle was also found to be 10% below its 1.05 ml/s rating
and, therefore, this reduction of heat input has to be considered in compari-
sons of performance based on net flue gas temperature.) Although both the
Lennox burners operated smoke-free in steady state at SR =r 1.25, cyclic fir-
ings showed a higher excess air requirement for
-------
The pseudo-steady-state thermal efficiency of the integrated furnace is com-
pared with that of the two stock Lennox furnaces in Fig. 15. No explanation
has been found for the disparity between the measured efficiencies of the two
stock Lennox units, although it now appears that the operating line on Fig. 15
for the No. 2 unit is probably more representative of the design's capabili-
ties than is that of the No. 1 unit. The performance of the integrated fur-
nace fired at 1.05 ml/s was quite comparable with the No. 2 stock furnace,
with an indicated steady-state efficiency in the neighborhood of 80%. A sub-
stantial number of additional tests of the integrated furance were made, in-
cluding some at reduced firing rates. During that testing, it was discovered
that there was a problem with the smoke meter being used (which is discussed
in a later subsection) and that the integrated furnace smoke emissions were
actually higher than had been believed. One result of the investigation into
that problem was a recommendation that the integrated furnace be downrated,
from a 1.05 ml/s (1.0 gph) nominal firing rate to 0.79 ml/s (3/4 gph). Re-
ducing its firing rate to 0.79 ml/s increased the achievable efficiency to
approximately 85%.
30
5 25
Z
en
01
I
20
g 15
(9
Z
in
DC
O
10
15
—— SMOKE < NO 1
SMOKE :, NO. 1
® OPERATING POINT
APPROXIMATELY BOX OF
EXISTING FURNACES OPE RATE
IN THIS ZONE
STOCK FURNACE NO. 1
. INTEGRATED FURNACE
10.71 ml/i)
70
75
80
U _.
z o
SO
OC -1
„ C/5
85 2 <
|N
90
CO
14
13
12
11
10
VOLUME PERCENT CO2 (DRY BASIS) IN FLUE GAS
L ^_ i . J . i -, I . I . I . I . I . I .
1.0
1.2 1.4 1.6 1.8
STIOCHIOMETRIC RATIO
2.0 2.2
Figure 15. Thermal efficiencies of the integrated
the stock furnaces
and
Winter Simulation Experiments. A series of integrated furnace tests was
made in which very cold air was supplied to the burner to simulate the admis-
sion of subzero combustion air through the sealed air system. A refrigerated
frozen foods transport truck was rented to serve as a source of cold air. It
was found that the truck enclosure could be maintained at — 15 C (5 F) while
drawing enough air to fire the furnace at 1.05 ml/s. The cold air was piped
approximately 5 m (16 feet) directly to the burner's air inlet through a
30
-------
fiberglass-insulated 0.1 m (4 inch) diameter PVC pipe. At steady-state, tem-
peratures as low as -10 C (14 F) were achieved at the burner inlet. The air
in these experiments did not flow through the sealed vestibule, where exper-
ience shows it would have been warmed up by 10 to 15 C. Therefore, the ob-
served data are believed to apply conservatively to outdoor ambient tempera-
tures at least 10 C (18 F) lower than the reported burner inlet temperatures.
Scheduling of winter simulation tests was greatly influenced by meterological
conditions (e.g., temperature, sunshine, wind, etc.) and this resulted in the
coldest burner inlet condition (Tair = -10 C) being tested first (Runs 61 to
69, Appendix C). A study of the flue gas measurements data shows no notable
effect of cold combustion air on the gaseous pollutant concentrations. There
were, however, readable traces of smoke recorded, and these were believed at
that time to be the result of the colder air. It was found in subsequent am-
bient combustion air condition firings (Runs 70 to 76) that the same level of
smoke was still being recorded. Removal of the burner revealed that the axial
alignment of the oil nozzle assembly had drifted to a slight upward bias,
causing partial impingement of the oil spray on the top edge of the choke
plate orifice. The nozzle alignment was corrected and Runs 77 to'79 (ambient
temperature) showed a corresponding correction of the traces of smoke emis-
sion. Cold-air tests were again scheduled; however, warmer weather prevailed
and -10 C combustion air temperature conditions could not be repeated. A
series of firings was conducted at zero C combustion air temperature condi-
tions (Runs 80 to 84). No smoke was measured, even to as low as SR = 1.07.
The general operation of the furnace seemed even to improve at these freezing
conditions, with smoother starts and quieter (i.e., more stable) combustion
than with ambient air. The characteristic start spikes In CO and UHC emis-
sions recordings were approximately 20 to 30% smaller thanl those seen in
ambient-temperature tests. Several more attempts were made to repeat the
-10 C temperature condition to check the correction of smoke emissions; how-
ever, weather conditions were not favorable and -8.5 C (Runs 88 to 91) was
the lowest combustion air temperature reached. The results again show low
pollutant emissions at design operating conditions (SR ~1.15) with the smoke
problem under control.
There is a ±15 C difference in net flue gas temperatures among the three (-10,
0, 15 C) sets of firings, corresponding to a ±0.5% difference in thermal
efficiency. This difference is on the order of data scatter and, therefore,
no firm conclusions have been based on these differences. Based on the ex-
cellent operational and consistently low emissions behavior of the prototype
integrated furnace unit in these direct-plumbing cold-air tests, no cold-air
related problems are anticipated in the field resulting from the use of the
sealed combustion air system.
An experiment was conducted to determine the change in combustion air flow
with changing air temperature. The complete burner cold-flow calibration
apparatus was installed in the refrigerated enclosure and the blower was ope-
rated continuously while the enclosure's air temperature was reduced from
21 C (70 F) to -7 C (20 F). The change in air flowrate pumped by the burner
blower was simply directly proportional to the change in air density (which
in turn, is inversely proportional to the absolute temperature). Therefore,
31
-------
in very cold ambient conditions, the operating stoichiometric ratio would
increase, producing a slight reduction in thermal efficiency, but without
forcing the burner into adverse operating conditions.
Smoke Emissions Experiments. The Rocketdyne Environmental Systems Labor-
atory has had, for some time, two Bacharach Model RCC-B hand-operated smoke
pumps. However, in preparation for field testing, two additional pumps were
purchased. During normal experimentation with the integrated furnace unit,
one of the new smoke pumps was used, and it was found that what had previously
appeared to be a 0 to 1/2 Bacharach smoke reading with one of the existing
pumps was now a 2-1/2 to 3 (Runs 135 and 136, Appendix C) reading with the new
pumps. The suspect pump was disassembled and nothing obvious or unusual
(e.g., cracking or tearing of the rubber piston) was found. The pump was well
lubricated and the flexible inlet tube showed no signs of cracking. A water
volume calibration device was set up in the laboratory where air drawn out
from an enclosure would be replaced in volume by water drawn in from a larger
water-filled container. It was calculated from the area of the smoke spot and
the required 10 strokes that one stroke should equal approximately 180 ml.
All four (two new, and two existing) smoke pumps were checked and the two
newly acquired pumps were found to draw about 160 to 164 ml. The existing
laboratory pump that was not being used drew about 150 ml. This 8 to 10% de-
gradation was approximately what was expected for a well-used hand pump, and
well within the accuracy of the human eye, reflectivity comparison method of
the Bacharach smoke scale. However, the pump that had actually been in recent
continuous use drew, at best, only 100 ml and showed greater sensitivity to
stroke rate. Complete disassembly and cleaning revealed that the check valve
was faulty and that the piston cap was cracked. Thus, the indicated smoke
readings were low for the then current tests and for previous tests over some
indeterminate time period.
Because of the conversion sequence from the original stock Lennox to the pro-
totype to the integrated furnace, it was not possible to go back and retest
those earlier configurations. However, the original stock Lennox burner was
tested in the No. 2 stock Lennox furnace, and several exploratory modifica-
tions were made to the integrated furnace and its optimum burner to simulate
the prototype configuration. It was concluded from the results that the prob-
lem with the smoke meter probably developed sometime between the stock Lennox
furnace tests and the prototype furnace tests reported in Ref. 3. That is,
the prototype unit's smoke emissions actually must have been appreciably
higher than were reported. This put a serious question on the integrated
unit's capability to be tuned to the nominal (15% excess air) design point.
The integrated furnace was retested, therefore, to determine operating condi-
tions which produce acceptably low smoke. Some of the results are plotted in
Fig. 16. At the 1.0 ml/s (1.0 gph) firing rate, smoke emissions were sensi-
tive to excessive overfire draft conditions and in all cases exceeded No. 1.
(Achievable upper values of stoichiometric ratio were restricted by combustion
air-flow limitations.) At the 0.79 ml/s (0.75 gph) firing rate, there was
almost no sensitivity to overfire draft variations, and less than No. 1 smoke
was generally measured if excess air exceeded 20%. It was also found that, at
this firing level, smoke emissions could be reduced further by insetting the
burner head a small distance—0.025 m (1.0 inch)—into the combustion chamber.
32
-------
Ul
1.05 ml/l FIRING RATE
10 P. 10.04")
I
I
Ul
a4
019 ml/1 FIRING RATE
10f><(004
BURNER INSET
0026m 110")
1.0 VI 1.2 1.3
STOICHIOMETRIC RATIO
1.4
1.0 1.1 1.2 1.3
STOICHIOMETRIC RATIO
1.4
Figure 16. Cycle-averaged smoke emission characteristics of the
integrated furnace tested on 4-minute-on/8-minute-off
firing cycles
Ostensibly, No. 1 smoke at SR >1.15 can be achieved with the latter combina-
tion of firing level and burner/firebox configuration. However, the gradient
in smoke number with decreasing stoichiometric ratio is quite steep so that
attempting to tune the burner to precisely 1.15 SR involves the risk of pro-
ducing excessive smoke if it is missed, or later drifts, by even a small
amount. From these results, it is apparent that the integrated furnace should
be rated as a nominal 0.79 ml/s (0.75 gph) unit, rather than the previously
stated 1.05 ml/s (1.0 gph), and tuned to burn with about 20% excess air. At
these redefined nominal design conditions, the measured steady-state and
cycle-averaged emissions of CO were 0.25 and 0.60 g/kg, respectively, and of
UHC were 0.02 and 0.04 g (as City)/kg, respectively. Measured emissions of
NO were slightly higher than at the former nominal design point, principally
because of the stoichiometric ratio change.
Laboratory Measurement of Nitric Oxide. The nitric oxide concentrations
in some of the tests reported on in this section appeared to be about 10 ppm
higher than had been observed in the past, and some experiments on the samp-
ling system and the sample analysis instruments were conducted to isolate the
source of the difference. It was quickly established, and later confirmed by
inquiries to other researchers, that the gas drying column, containing a 3A
33
-------
molecular sieve topped with indicating Drierite (cobalt salt/CaSO^), in-
fluences the NO concentration measurement when newly replenished. The column
showed no influence with the calibration gases (NO in N2). However, with flue
gas containing hydrocarbons, oxides of carbon, and sulfur, along with water
vapor, the column absorbed significant amounts of nitric oxide along with
water vapor until it apparently saturated to some condition during the first
day of use, so that it would thereafter absorb only the water vapor. This
absorption of NO was noted on both nondispersive infrared (NDIR) and chemil-
uminescent (CL) analyzers. However, further experiments revealed that, while
analyzing flue gas samples, some combination of molecular sieve and new indi-
cating Drierite can cause the NDIR analyzer to read —10 ppm higher than the
CL analyzer; this apparently was the cause of the recently observed discrep-
ancy. The CL analyzer is the intended instrument for the field test evalua-
tion so, rather than exploring methods of optimizing the NDIR/drying column
combination, the sample train was modified to utilize only the CL analyzer for
oxides of nitrogen. This better conforms to the planned field test instrumen-
tation and to that of many other researchers.
FINALIZED DESIGN OF THE INTEGRATED FURNACE
The extensive testing of the first integrated furnace unit, described above,
yielded considerably greater understanding of its operation and performance,
and led to adjustment of the nominal design point operating conditions. How-
ever, surprisingly few actual physical design improvements resulted from that
work. None of the design changes were substantive.
As it became apparent that the initial design was not going to be changed
appreciably, commitments were made to obtain stock furnaces and components
needed to assemble, first, two new integrated furnace units to be used in de-
sign verification studies and, finally, four more units to bring to six the
number available for installation in homes in the field.
The optimum low-emission burner assembly is shown in Fig. 17. Clearly visible
in this photograph are the external modifications that distinguish this burner
from the Beckett Model AF, from which it was derived. The sheet metal optimum
head with its welded-on external sheet metal flange is mounted on the end of
the shortened blast tube. The draft control assembly, which serves as the
combustion air inlet, is nested between the fuel pump and the body of the
burner. The microswitch for sensing proper opening of the draft flat is
mounted inside the draft control assembly, so it is not seen in Fig. 17. The
starting shunt relay (Fig. 6) is visible to the left of the ignition
transformer.
A photograph of the cast iron firebox was shown earlier in Fig. 7, and more
detail may be seen in Fig. 8 which shows two views from the fabrication draw-
ing. This design remained unchanged throughout the Phase I design optimiza-
tion studies.
The firebox is shown installed in the integrated furnace in Fig. 18. The
simplicity of the welded attachment of the fabricated sheet metal heat ex-
changer to the cast iron firebox is evident in that photograph. Also visible
are the vertical, sheet metal baffles on each side of the firebox that
34
-------
COMBUSTION AIR
INLET, DRAFT
CONTROL ASSEMBLY
IGNITION
TRANSFORMER
STARTING-SHUNT
RELAY
FIREBOX
ATTACHMENT
FLANGE
DRAFT
FLAP
VALVE
MOUNTING
STAND
50P21-6/3/77-S1
Figure 17. Optimum low-emission oil burner
35
-------
FLUE GAS EXIT
MANIFOLD
MAIN HEAT
EXCHANGER
FIREBOX
ACCESS !
PORT
WELDED
JOINT
BURNER
MOUNTING
LATE
BT.OWER DISCHARGE OPENING
SIDE WALL
INSULATION
50P21-5/26/77-S1C
Figure 18. Internal construction of the integrated furnace
36
-------
partially restrict the expansion of the warm-air stream which flows up from
the blower discharge opening. The bottom edges of these baffles are approx-
imately 2 inches inboard of the positions of their counterparts in the orig-
inal stock Lennox units. The stock Lennox relied upon air gap insulation to
limit heat transmission through the side walls of the cabinet. In the inte-
grated furnace, additional insulation was installed in the side walls because
the air gap had been made wider. High-temperature Johns-Manville 1/2-inch-
thick Cerafelt insulation with foil on both sides was glued to the cabinet
side walls and slipped into the existing air gap on the back wall. It ex-
tended on all three sides from the level of the blower discharge opening to
the top of the furnace cabinet.
LABORATORY VERIFICATION STUDIES
Two units of the finalized integrated furnace design were assembled for use in
laboratory verification studies. One was sent to the Underwriters Labora-
tories for their independent professional evaluation of potential problems in
conforming to applicable residential oil furnace safety standards. The other
was tested in the Rocketdyne laboratory to verify that the performance and
emissions of the finalized design meet the design goals and, as well, to
assess experimentally the satisfaction of safety standards.
Preliminary Examination of the Integrated
Furnace by Underwriters Laboratories
Integrated Furnace Unit No. 1 of the finalized design was tested briefly in
the Rocketdyne laboratory to make sure that all of its components functioned
properly, then it was sent to the Underwriters Laboratories, Inc., Heating,
Air Conditioning, and Refrigeration Department in Northbrook, Illinois.
There, it was subjected to a preliminary examination, which is the first step
UL takes in the process of listing a commercial applicance or component as
conforming to applicable safety standards. In the preliminary examination,
the furnace was inspected thoroughly, including partial disassembly, but no
tests were conducted. Also, because the specimen sent was destined to be one
of the units field tested, it was stipulated that UL should avoid damaging
components during their disassembly and inspection.
The results of the preliminary examination were reported in a UL letter to
Rocketydne.dated 19 July 1977. Approximately 35 comments or questions were
submitted concerning lack of conformance to particular paragraphs of oil
burner and central warm-air furnace safety standards. Nearly every one of the
points raised could and should be responded to by effecting appropriate design
modifications before undertaking commercial manufacture of these furnaces. On
the other hand, many points seem to be of little consequence with regard to.
field testing'a limited number of custom-assembled units for the relatively
brief period of one winter heating season. Therefore, the UL comments and
questions were considered, one by one, specifically with respect to field
testing, to determine whether and what design changes should be made immed-
iately to ensure safety of the test furnaces.
37
-------
The UL report is reproduced in Appendix D. To the right side of each of the
numbered UL comments a statement is given concerning the action that Rocket-
dyne was later (Phase II) to implement for the six field test furnaces. In
every case, it was the considered opinion that the indicated action (even if
it is "no action") could be taken without compromising the safety of the host
homes or service personnel.
Laboratory Testing
Integrated Furnace Unit No. 2 was tested in the Rocketdyne outdoor furnace
test laboratory. The initial firings resulted in carbon monoxide concentra-
tions approximately twice as much as anticipated, and after trying several
burner mounting positions (insertion into combustor port) the burner was re-
moved and it was found that the oil nozzle was misaligned. The problem was
corrected and the burner was reinstalled; the results of the subsequent flue
gas measurements are tabulated in Appendix E.
It was found during the initial checkout firings that the smoke characteris-
tics of this furnace assembly were insensitive to the burner insertion posi-
tion, so the burner was left in the flush-mounted position for those firings
and most of the following UL requirements testing. The results showed no per-
formance problems resulting from the techniques used in the assembly of the
field test units.
UL Failure Mode Requirements. The safety requirements for the integrated fur-
nace are specified in UL Standards No. 727 (ANSI Z96.1-1973) "Oil-Fired Cen-
tral Furnaces" and No. 296 (ANSI Z96.2-1974) "Oil Burners." Tests were con-
ducted using Integrated Furnace Unit No. 2 and its fully instrumented labora-
tory predecessor integrated furnace when extensive temperature measurements
were required. .The performance testing was conducted in compliance with Sec-
tions 33 through 48 in UL 727 and Sections 39 through 52 in UL 296, with only
minor variances in instrumentation and procedures. Excluded were sections
involving purely electrical tests of unmodified electrical components that are
already UL listed (e.g., Dielectric Withstand Test), or sections involving
different types of equipment (e.g., downflow furnace, vaporizing burner, etc.).
Table 2 presents a listing of the headings for the above sections for both UL
727 and UL 296 standards. Most of the requirements result in pass or fail
judgments, i.e., they require acceptable ignition/combustion (e.g., no back-
fire, less than No. 2 smoke, etc.) or a safety device lockout to prevent per-
sistence of any unsafe condition.
A series of hot firings investigated furnace response to variations in elec-
tical supply line voltage. The line voltage to the burner unit was controlled
by a "variac" transformer; the supply voltage was varied from 102 to 132 vac,
the range specified in UL 296, Section 45 testing requirements. The opera-
tion of the burner revealed no adverse mechanical effects, e.g., motor over-
heating, sparking, etc., at either the 102 vac undervoltage or the 132 vac
overvoltage settings. Ignition was smooth and combustion roughness was absent
throughout the voltage variations testing. The pollutant emission concentra-
tions remained within the nominal levels for the optimum burner. The stoich-
iometric ratio varied only sightly, about 2 to 3 percentage points from
maximum to minimum voltage settings.
38
-------
TABLE 2. LISTING OF UNDERWRITER LABORATORIES
PERFORMANCE TESTING REQUIREMENTS
Requirements of UL 727, "Oil-Fired
Central Furnaces"
Performance
Section 33.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
General
Test installation for standard clearances
downflou and upflow furnaces (for
installation in other than closets or
alcoves)
Enclosure
Chimney connector
Air outlet and inlet-forced-air
furnace
Horizontal furnace
Enclosure
Chimney connector
Air outlet and inlet
Test installation for alcove or closet
Dounflou, upflou, and horizontal
furnaces
Enclosure
Chimney connector
Air outlet and inlet
Instrumentation
Draft
Fuel input
Power measurement
Speed measurement
Static pressure
Temperature measurement
Initial test conditions
General
Furnace equipped with mechanical
atomizing burner
Furnace equipped with vaporizing
burner
Static pressures for tests
Combustion test - burner and furnace
Operation tests
Limit control cutout test
Continuity-of-operation test
Air for, downflou, or horizontal
furnace test
Temperature tests, general
Continuous operation test
Blocked inlet test
Fan failure
Stalled fan motor test
Blocked outlet test
Requirements of UL 296,
"Oil Burners"
Performance
Section 39. General
40. Draft
41. Fuel input
42. Power measurement
43. Speed measurement
44. Temperature measurement
45. Test voltage
46. Combustion tests
Mechanical atomizing burner
Vaporizing burner test
47. Combustion air failure test
48. Interruption of atomization test
49. Undervoltage test
50. Power interruption test
51. Temperature test
52. Ignition tests
39
-------
A combustion air failure requirement, UL 296, Section 47, requires only that,
upon interruption of the combustion air supply system (burner blower), the
burner either terminates the firing or, if the firing continues, no unsafe
condition is created. The optimum burner satisfies this requirement with its
conventional direct-drive fan and fuel pump arrangement. Additionally, the
optimum burner's inlet air draft flap microswitch circuit ensures that an
acceptable amount of air is being supplied through the inlet system (e.g.,
outside air plumbing, filter, draft flap, etc.).
The maximum temperature tests (UL 727, Section 43 and UL 296, Section 51),
however, require fairly elaborate temperature measurements to be recorded, and
the pass or fail judgment is determined quantitatively. Unit No. 2 was used
for the initial limit control cutout tests—93.3 C (171.1 F) maximum allowable
warm-air temperature. During this test it was found that the approximate
temperature scale on the limit control dial does not correspond closely with
the actual warm-air temperature. The temperature limitation stops were re-
adjusted to comply with the above UL requirement, whether this is a typical
characteristic of the integrated furnace or of the limit switch was left to
be determined in Phase II when the other field test units are fired.
The testing was then shifted to the laboratory furnace unit for the component
temperature measurement tests (UL 727, Sections 44, 45, 46, and 48). The
primary concerns here were the sealed vestibule, which is markedly different
from industry practice, and the cast iron firebox configuration. Table 3
presents the maximum temperatures measured, along with the corresponding
allowable UL temperature specifications for the given conditions. As can be
seen from these data, the components in contact with the combustion gases
were well within the maximum allowable temperatures. However, due to the
high air temperature rise [52 C (94 F) above ambient] reached in the sealed
vestibule during continuous operation at 5 C (9 F) below limit control cut-
out temperature, electrical components in the vestibule were close to the
temperature limits for standard wiring. Standard (Type ST) appliance cord had
been used to wire the draft flap microswitch circuitry, following a furnace
manufacturer's suggestion that one should attempt to UL-qualify furnace wir-
ing with standard insulation wherever possible so as to avoid the possibility
of uncontrolled wire replacements in the field creating unsafe conditions.
However, these tests revealed the need for higher temperature, i.e., 90 or
105 C (194 or 221 F) rated wire for this application, so plans were imple-
mented to change all units to 105 C (221 F) wiring before field installation
of any of the integrated furnaces.
Unusually high vestibule air temperatures, i.e., 78 C (172 F) maximum,were
measured when the furnace was operated with unusually lowCair flowrates
£0.330 m3/s (£700 scfm) on a maximum-demand firing cycle. The maximum vesti-
bule air temperature measured during a typical 4-minute-on/8-minute-off at
nominal conditions was relatively low, on the order of 46 C (115 F), so no
unusually rapid furnace degeneration in the vestibule area (e.g., paint peel-
ing, rubber cracking, etc.) is anticipated during the field tests. Nonethe-
less, telephone inquiries were made to the manufacturers of the primary con-
trol and the draft flap relay to verify their long-term reliability under
those conditions.
40
-------
TABLE 3. MAXIMUM TEMPERATURE RISES MEASURED ON THE INTEGRATED FURNACE
TESTED IN COMPLIANCE WITH UNDERWRITERS LABORATORIES SPECIFICATIONS
*>X~>*>^^>^ Te8t
Temperature, C"*^*^^.
Burner head
Blast tube
Ignition transformer
Burner motor
Fan motor
Vestibule filter
Burner wiring
Combust or
Heat exchanger
Cabinet
Section 44
continuous
operation
334/351*
215/292*
62
72
21
43
52
433
294
27
UL
maximum
711
517
65
80
75
50
35/80**
517
517
50
Section 45
blocked
Inlet
305
191
57
65
21
33
46
407
285
~
Section 46
fan
failure
302
227
47
45
—
17
28
289
~
~
Section 48
blocked
outlet
322
205
70
72
21
50
56
418
296
—
UL
maximum
822
683
90
115
115
97
60
683
683
97
*Burner inserted 0.
**Allo«able for 105
0254 m (1.0 inch) into combustor
C (221 F) rated appliance wire
In summary, the laboratory testing of the integrated furnace according to the
UL Performance Requirements for oil burners and oil-fired furnaces revealed
only a need for higher temperature rated wiring on one circuitry. This cor-
rection will be made on all field test units, and the likelihood of any
unsafe operation will be minimized.
41
-------
SECTION 6
FIELD VERIFICATION
The basic approach to the field verification testing is to utilize a limited
number of integrated furnaces as the space heating sources in as wide a vari-
ety as possible of existing oil-fueled residences. The objectives of this
task were to evaluate and finalize all details of field testing up to the
actual assembly and shipment of hardware for testing during the 1977-1978
winter season. This involved evaluating and selecting of test areas, arrang-
ing local test support, and determining the test measurement methods. Many
of these evaluations are closely interrelated, and the overall scheme was
determined in an iterative manner.
TEST LOCALE SELECTION
This effort proceeded on the basic premise from earlier evaluations of utiliz-
ing six furnace units, in two different winter climates, in high fuel oil
heating areas. Oil heating is concentrated in three general regions of the
U.S.: the New England states, the Great Lakes states, and the northern mid-
Western states. Because these are all far from Rocketdyne's main plant in
California, consideration of several logistics aspects also was involved in
selecting test locales.
Three field test units are to be located in each of two test locales where oil
heat is used in a substantial fraction of single-family homes and which have
distinctly different winter climates. As a start toward selecting the two
Icacales, winter climatic data averaged over several prior years were reviewed
for approximately 35 cities, most of which are distributed throughout the
three geographic regions mentioned above. Data considered were: annual and
monthly degree days; monthly average temperatures and precipitations; and
average diurnal temperature ranges (Ref. 9). All cities considered have
normal accumulative degree days, based on 18 C (65 F), exceeding 2500 C-day
(4500 F-day) for the 9-month period of September through May. Monthly average
temperature data were plotted directly and on a weighted basis, using U.S.
census (Ref. 10) data on the number of households in each city. Mean curves
were drawn through these two sets of data and were found to differ by only 1 C
(2 F). Comparing the individual cities' weighted, monthly-averaged winter
temperature profiles to the corresponding mean curve, 30 of the 35 cities had
annual temperature profiles within ±5% of the mean. Thus, it was inferred
that the weighted mean temperature profile is representative for a majority
of the households in the colder regions of the 48 contiguous United States.
42
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Based upon their closeness to the weighted mean temperature profile, seven
cities were selected as being most representative; they were: Boston, MA;
Cleveland and Columbus, OH; Indianapolis, IN; Providence, RI; Scranton, PA;
and Springfield, IL. Comparisons of total winter precipitation and diurnal
temperature ranges revealed that these cities experience two broadly distinc-
tive winter weather patterns. The maritime climatet represented by Boston and
Providence, encompasses the eastern seaboard. It probably extends inland for
no more than a few dozen miles. Because of its proximity to Lake Erie, Cleve-
land's climate also falls in that climatic category. The continental climate,
typical for the inland cities of Springfield, Indianapolis, Columbus, and
Scranton, is characterized by wider diurnal temperature variations and less
total precipitation than are experienced in the maritime climate. It was con-
cluded that one test locale should be selected within each of those two gen-
eral climatic categories.
Attention was then directed to nonclimatic factors, such as oil usage pat-
terns, predominant types of residential construction, state and local code
requirements, and availability of local support. Data'concerning pertinent
housing characteristics for 11 candidate locales are listed in Table 4. As
can be seen in Table 4 all of these candidate locales well exceed the 2500 C-
day (4500 F-day) degree-day heating load and there is significantly greater
usage of fuel oil in the extreme northeastern/New England states. Because of
the predominant use of oil for residential heating in New England, an assess-
ment was first made of metropolitan Boston as the test locale with a maritime
winter climate. From several standpoints, this area was found to be very
attractive: there are very broad ranges of house ages, architectural styles,
construction materials, degrees of insulation, and wind exposures; nearly all
of their central heating systems are oil fueled; the only code requirements
imposed on an experimental furnace is that the burner have a Massachusetts
Fire Marshal approval number; there are reliable, well-established furnace
equipment distributors willing to provide installation and service support for
field testing; there are several environmental testing laboratories in the
area; and, finally, there are regular and convenient travel and shipping con-
nections to Los Angeles, CA. Therefore, Boston was tentatively selected as
the. maritime climate test locale. Emphasis then shifted to making subcontract
arrangements for local installation and service support and laboratory support
in Boston and, simultaneously, arriving at a tentative selection of a locale
with a continental climate.
It appeared from the initial Boston contacts that laboratory support might be
more difficult to arrange than either service support or host homes. It was
considered that the larger metropolitan areas were most likely to have qual-
ified, well-instrumented laboratories, so the order of examining cities with
continental climates was established as from the larger to the smaller. Thus,
even though oil has only a small fraction of residential heating there, Pitts-
burgh got first consideration. One or two apparently qualified labs were
identified and an interested service contractor was found who has a substan-
tial oil-heating background and several oil clients as potential host home-
owners. Therefore, Pittsburgh was tentatively selected as the continental
climate test locale.
-------
TABLE 4. PERTINENT HOUSING CHARACTERISTICS FOR ELEVEN CANDIDATE CITIES
September through May
Candidate degree-days Thousands of
city (°F-days) housing units
Boston
Providence
Hartford
Chicago
Toledo
Cleveland
Indianapolis
Scranton
Columbus
Pittsburgh
Albany
5586
5926
6314
6093
6105
6088
5561
6067
5681
5881
6818
891
263
212
2291
186
676
369
79
296
789
98
With warm-
air furnace , %
24
82
22
45
68
71
70
11
81
69
25
Heating use
fuel oil, % With basement, % Comment
66
66
68
13
12
6
31
46
8
6
43
94
94
26
83
62
84
53
89
77
92
90
Atlantic
maritime
climate
Great Lakes
maritime
climate
,
Continental
climate
-------
However, as the details of field testing in these specific cities were being
formulated and negotiated it was found that the final competitive bid re-
sponses from analytical laboratories were much higher priced than the initial
responses. Subcontracting of the flue gas analysis effort was then deemed
impractical, and an option involving a mobile Rocketdyne instrumentation unit
was formulated. It was apparent that with a single mobile unit to cover both
test locales, many advantages could be realized with a reduction of the dis-
tance between the two locales. A review of the climatic data revealed Albany,
NY as an excellent continental climate test site, separated from the Atlantic
maritime climate by the Appalachian mountain range, and less than half as far
from Boston, MA as Pittsburgh, PA.
The climate in Albany, NY during the heating season is somewhat colder than
that in any of the other 10 cities considered in the initial evaluation. The
mean temperature of Albany is 5.1 C (41 F) during the heating season as
opposed to 6.5 C (44 F) for Boston. The apparent difference between these
mean temperatures is actually a little smaller than the difference in the
numbers of degree-days listed in Table 4. However, both criteria indicate
that the thermal load is substantially greater for Albany than for Boston.
SUPPORT IN TEST LOCALES
Service Support
The selection of the local furnace service support started as a general evalu-
ation of any furnace service contractor in the-selected metropolitan areas.
However, the process of evaluation quickly revealed that there are many ad-
vantages to working with distributors of the same brand name (Lennox) furnaces
from which the integrated furnace was derived. These service contractors were
more knowledgeable in the specifics of the construction, installation, and
operation of the stock predecessor unit. The availability of spare common
parts through these service contractors reduces the likelihood of unexpected
delays. Moreover, many of these franchised service contractors were informed
of some Lennox studies on fuel conservation devices, e.g., sealed air systems,
which relate to the integrated furnace unit. The final selections of service
contractors were made by standard contract bidding procedures and confirmed
by visits of Rocketdyne personnel to the candidate organizations.
Selection of Host Sites
A list of potential host dwellings was supplied by each of the two service
contractors from their existing customer lists. The selection of the six
host sites (single-family dwellings) was based on criteria that included con-
sideration of: (1) dwelling construction, (2) dwelling location, (3) existing
dwelling furnace installation, (4) fuel usage history, and (5) host family.
The dwellings with basement installations were preferred simply for the ease
of accessibility and the space available for the required instrumentation
packages. Other dwelling construction factors (e.g., building materials, age,
number of levels, type of insulation, etc.) were considered to obtain a var-
iety of dwellings with varying thermal characteristics. The thermal charac-
teristics of a dwelling can also be influenced by its location where there
45
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could be significant localized differences in wind, insolation, heat retention
(ground or water), etc. The integrated furnace configuration has been tested
at return air flowrates from 0.425 m3/s (900 scfm) to 0.800 m^/s (1700 scfm)
and return air temperature varying from 10 C (50 F) to 32 C (90 F) with little
or no effect upon its operation. Therefore, the existing furnace installations
in the candidate dwellings were evaluated primarily on the basis of geometric
compatibility with the integrated furnace and the field test instrumentation
requirements.
The fuel usage history considered was data for the two previous heating sea-
sons so that correlations with degree-day data could be made to normalize all
the thermal efficiency data to one baseline. This correlation may also reveal
the necessity for an adjustment factor for changes in lifestyle (e.g., lower-
ing of thermostat settings) induced by recent energy conservation campaigns.
The requirement for the host family themselves is stability of the number of
occupants during this and the previous two heating seasons. If, for example,
there is a college student in,say, a small family of four, who will not be re-
siding in the house this season, the thermal load upon the heating system may
be affected significantly. However, if the student had also been gone in the
previous two heating seasons, or if the dwelling is constantly occupied (e.g.,
kept heated) by another member of the house, the effect would be negligible.
The ages of the children were noted as host families without children from 1
to 8 years of age were preferred. The concern here was the likelihood of in-
quisitive tampering with the instrumentation (e.g., pulling the power cord) by
children in this age bracket. Although it is not listed as a criterion, a
major influence upon the final selections was the attitudes of the host fam-
ilies toward the field test. Since the field test is of long duration (9
months) during adverse weather conditions and in two different cities, it is
very probable that delays will arise, and these could be compounded greatly
by an uncooperative host. Therefore, enthusiasm and cooperation are valued
traits in the host families.
Integrated Furnace Installations
The installations of the six integrated furnaces are scheduled for the month
of Sepetember 1977 and all are to be operational by the first day of October.
Each installation will involve the removal and storage of the existing furnace
and the mounting of the integrated furnace. The warm-air ducting will require
minor modifications to allow the temporary insertion of a 0.45 x 0.45 x 1.22 m
(18 x 18 x 48 inches) laminar flow element section and various thermocouple
probes for cyclic thermal efficiency measurements. A full complement of in-
struments to evaluate thermal efficiency will be installed on one of the fur-
naces while the remaining five furnaces will have time event recorders to
monitor furnace operations and store this information on magnetic tape (cas-
sette) . The thermal efficiency measurement apparatus will be rotated through
the other five host sites during the heating season to obtain efficiency
characteristics of all six units. The field test will terminate at the end of
May 1978, at which time the integrated furnaces will be removed and the dwell-
ings restored to their original conventional furnace configurations.
46
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TEST MEASUREMENTS
The field test evaluation involves periodic measurement of flue gas emission
concentrations and continuous event monitoring of cyclical operations. The
primary objective of the test is to observe the long-term pollutant emissions
characteristics of the integrated furnace design. A secondary objective is
to establish the overall season-averaged thermal efficiency of the furnace so
that the pollutant emissions results can be evaluated in light of the present
concerns for energy conservation.
Air Pollutant Emissions
The long-term monitoring of flue gas pollutant emission concentrations will be
conducted with measurements at monthly intervals. The pollutants to be meas-
ured are: nitric oxide (NO) and total oxides of nitrogen (NOX) by chemilum-
inescence; carbon monoxide (CO) by nondispersive infrared; unburned hydrocar-
bons (UHC) by flame ionization; and smoke by the Bacharach method. In
addition, carbon dioxide (C02) by NDIR and thermal conductivity and oxygen
(Oo) by polarography will be measured to determine the operating conditions
by stoichiometry. All of the instruments, with the exception of smoke pumps,
will be installed into and operated from a 3/4-ton capacity van mobile labor-
atory. The van will transport the instruments to each host site, and a
0.0064 m (0.25 inch) diameter FEP Teflon line will be connected to the flue
at a point near the furnace to conduct the flue gases to the analyzers. The
control of the furnace will then be locked into a 4-minute-on/8-minute-off
operating cycle by a repeat cycle timing device. After the calibration pro-
cedure, sample transport pumps within the van will be turned on to draw
samples continuously from the flue and the gases will be analyzed throughout
the 4-minute firng cycle. CO and UHC concentrations characteristically
"spike" on startup and, therefore, the concentration profiles for these
species will be recorded on continuous-drive paper charts. These pollutant
emissions will then be averaged over the 4-minute firing and compared from
month to month in terms of their cycle-averaged values. The integrated fur-
nace has consistently operated in the laboratory at SR = 1.20, smoke
-------
strictly controlled, i.e., unlikely to cover test locales 325 km (—200 miles)
apart. An "uncontrolled" fuel oil supply procedure would enhance the field
test aspect of the task with the insertion of typical service routines, while
requiring more effort in normalizing the resultant data. To gain the advant-
ages of both the controlled and the uncontrolled oil supply procedures, the
field test will be conducted with oil being supplied uncontrolled by the hosts'
present oil suppliers, recording only the volume delivered. At the time of the
monthly emissions measurement vist, a 500 cm3 sample will be extracted at the
burner pump and cataloged for future reference. Should any furnace emissions
data appear anomolous, the associated oil sample would then be sent out for
analysis.
Thermal Efficiency
Steady-state thermal efficiency of a furnace unit is normally estimated only
in terms of the heat rejected out the flue during a continuous firing. This
involves simply measuring the net temperature and the composition of the flue
gases as described in the laboratory testing section. The flue pipe on all
test installations will be insulated for approximately 0.6 m from the furnace.
Measurements will be made 0.46 m from the center point of the furnace exit
manifold in either a vertical or horizontal run as determined from the actual
installation.
However, the accurate measurement of the cyclic operating thermal efficiency is
complicated greatly by heat sinking of components, the need to measure very
low pressure drop flows, relatively inconsistent furnace controls (e.g., bi-
metallic spring fan control), and nonuniform flow conditions. Each of these
factors introduces variables that result in considerable data scatter. The
measurement of season-averaged thermal efficiency is complicated further by
variable cycle timing. For these reasons, substantial season-averaged thermal
efficiency values have not been reported; instead, estimates have more often
been reported. The influences of the many variables mandate statistical anal-
ysis techniques for evaluating season-averaged thermal efficiency. Therefdre,
continuously monitoring, automatic data acquistion methods were devised to
record a large number of data points for a valid statistical analysis.
A Hewlett/Packard System 3051A data logging system with a programmable central
controller will be used on one furnace to monitor all the timing, temperature,
and flow parameters once every 4.5 seconds, and data from each firing will be
stored on magnetic tape. The system utilizes eight of ten available data
channels (see Fig. 19) for monitoring furnace status, warm-air flowrate, and
warm-air net temperature. The cycle on and off times are determined by a
counting of the number of data scans multiplied by the appropriate scan rate
time constant. Upon sensing burner power on Channel 1, the burner on-time
(i.e., heat input) counter is started and the logic for determining the maxi-
mum net flue gas temperature reading (Tpc^VEST* Channels 7 and 8) is activa-
ted until burner-off is sensed. Whenever the warm-air fan power is switched
on (Channel 2), the summations of measurements of warm-air inlet temperature
(Channel 3), pressure drop (Channel 6) through the laminar flow element and
outlet temperature (Channel 4) are taken until fan-off. These summations are
then kept until the moment of the next burner-on to include any warm-air fan
48
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Data Logger
H/P System 3051A
^——
Thermistor
(Conax TH13-SS12)
Chromel/Alumel
Thermocouples
Sensing Only
for t
BURN
FAN
Transducer
(Setra Hod. 239)
'REF
rFLUE
'OUT
TVEST
TIN
'BURN
VFAN
APAIR
(7)
(5)
(8)
(3)
(1)
(2)
(6)
Ref.
June.
Box
Return
Air
=: Laminar
= Flow
^n Element
Integrated
Furnace
System
|Oil Flowmeter
(Cumj-
>lative)
Figure 19. Schematic of automatic field test furnace efficiency
data acquisition system
-------
restarts resulting from residual heating or improper fan control unit opera-
tion. Chromel-alumel thermocouple junctions are used for all furnace tempera-
ture measurements with an insulated "floating" reference junction module,
i.e., varying temperature. A thermistor probe (Channel 7) is used to monitor
the referenced junction zone temperature, and this correction is applied to
all thermocouple measurements. Sensing burner-on again signals not only the
start of a new cycle, but also the end of the previous cycle and that the
acquired data should be prepared for storage. All summations of measurements
are normalized by the number of summations to establish a cycle-averaged value
and then reduced. The values stored on magnetic tape are burner-on time,
burner-off time, warm-air heat gain, and maximum net flue gas temperature. In
addition, the controller prints a running account of the number of firings,
cumulative on and off times, and the last file recorded on magnetic tape.
This system will result in cycle-averaged thermal efficiency data that are
correlated to cycle timing parameters and, eventually will be used to evaluate
season-average performance. The data from the primary programmable data log-
ger will be reduced on-site by the central controller on a monthly basis.
To evaluate season-average performance for all the furnaces, cycle timing will
be carefully monitored on the remaining five furnaces by Instrumenation Tech-
nology Corp., Model 9676 automatic event-time data loggers storing day, hour,
minutes, seconds, and on/off status information on magnetic tape. These
tapes will be retrieved monthly and evaluated on a G.E. 440 time-sharing com-
puter system. At various times during the test, each of the time data loggers
will exchange positions with the thermal efficiency data logger so that each
furnace can be characterized accurately.
The steady-state thermal efficiency of the integrated furnace at 0.79 ml/s
(0.75 gph) firing rate is 85%, which is about the maximum achievable for non-
condensing flue gas furnace systems. The cycle-average efficiency in actual
homes is expected to be approximately 5% lower at about 80%. The season-
average efficiency for the integrated furnace will be determined by the field
test. In addition, the fuel conservation effects of the sealed air system,
which does not appear in the above heat transfer evaluations, will be determ-
ined by comparison of the fuel consumption of the two previous seasons and
that of the field test season, all normalized by the degree-day heating re-
quirement index for each season. Overall reductions in fuel consumption re-
sulting from the installation of the integrated furnace are expected to be
well over 10% and might well be in the 20 to 25% range.
50
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SECTION 7
EVALUATION OF THE USE OF OTHER FUELS
The objective of this task is to evaluate the capability of the integrated fur-
nace to operate on other clean fuels. It is not intended to reoptimize the
furnace for other fuels, but simply to assess the capability of the existing
unit. Information acquired concerning pollutant emissions and efficiency
performance is then used to define additional research required to establish
low-emission combustion of other fuels in this and/or other types of space
heating equipment.
SELECTION OF CANDIDATE FUELS
Two classes of fuels are of interest in this task: (1) those currently used
for residential space heating, i.e., current competitors to No. 2 fuel oil,
and (2) those which may become available in the future as competitors or re-
placements for currently used fuels. The first class is strongly dominated
by natural gas. This is seen from the following percentages of U.S. homes
heated by various fuels (1970 U.S. Census): natural gas, 58.5; fuel oils,
27.5; bottled gases, 6.4; electric 2.8; and, all others, 4.8%. Thus, if an
alternate fuel is selected from this class of currently used fuels, natural
gas is the only logical choice.
There are a number of both gaseous and liquid potential fuels of the future
in the second class. Those include: hydrogen; substitute natural gas (SNG)
derived from coal, biomass and/or waste conversion; low-Btu fuel gases from
the same sources; liquid alcohol fuels, also from the same sources; and liquid
oils from shale and coal liquefaction processes. Martin (Ref. 11) recently
has reviewed the probable properties and combustion characteristics of many of
these fuels, so that information need not be repeated here.
Low-Btu gaseous fuels have significant concentrations of inert diluents (N2,
C02, H20 vapor) and/or partially oxidized fuel species (CO) which make it un-
economical to transport them very far from their sources. Thus, they are not
likely to be distributed by public utilities to vast numbers of residences.
The high-Btu SNG's, on the other hand, are far more likely to be distributed
widely because they will be specifically tailored direct substitutes for
natural gas, both in the pipeline distribution systems and in end-use consump-
tion devices. Thus, current experience with natural gas should be equivalent
to future behavior of SNG's. Hydrogen, conversely, has such different proper-
ties, composition, stoichiometry, etc., that an entirely new body of experience
will be needed before wide-spread distribution to homes will be possible. Thus,
residential use of H2 is probably much further in the future than is use of
SNG's. Moreover, since it is not carbonaceous, hydrogen's combustion and
51
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pollutant emissions characteristics are distinctly different from those of
natural gas and distillate oils. From these considerations it is seen that
natural gas is the one most logical gaseous fuel to consider as a candidate
alternate fuel in this task.
Synthetic oils from coal and shale tend to have higher densities, viscosities,
nitrogen contents, and carbon-to-hydrogen ratios than have No. 2 fuel oils from
petroleum. It is far from certain that these tendencies will still be appli-
cable to synthetic oils which one day might be distributed for residential
space heating. If they do, they undoubtedly will force adjustments in fuel
storage, pumping, atomizing, and ignition equipment as well as in excess air
levels and combustion chamber volumes required to minimize smoke and other
carbonaceous pollutants. In any event, fuel-bound nitrogen is likely to remain
as a particularly significant problem. Therefore, the emission of NOx from
fuel nitrogen is likely to exceed NOx from thermal fixation, and this is pre-
cisely opposite to the current situation with No. 2 distillate petroleum oil.
The integrated furnace design is based substantially on reduction of thermal
NOX by techniques that have not been particularly effective in reducing fuel
nitrogen-derived NOx, so tne synthetic oils may not be particularly attractive
as candidate fuels for this task.
Conversely, the alcohol fuels should be essentially free of fuel-bound nitro-
gen. They might be produced from petroleum feedstocks, as normal liquid alter-
nates to the cryogenic liquefied natural gas (LNG), or from a variety of con-
version processes for coal, bio-mass, and wastes. The compositions of alcohol
fuels will vary with the source, the conversion process, and the intended end-
use, but it appears that methanol, ethanol, and/or mixtures of one or both of
these with lesser quantities of higher-molecular-weight alcohols eventually
may be produced and marketed as fuels. Alcohols are partially oxygenated,
which may be viewed as having a water molecule imbedded in their molecular
structure, and this makes them less energetic and, perhaps, slower burning than
unoxygenated petroleum fuels with equivalent numbers of carbon atoms in their
molecules. These properties also contribute to some desirable combustion pro-
perties, viz., alcohol fuels tend to burn cleaner (i.e., lower production of
carbonaceous air pollutants) than hydrocarbon fuels with equivalent liquidity
and volatility. These differences become less distinct as the alcohol mole-
cular weight increases; i.e., they are most dominant with the lowest-molecular-
weight alcohol, methanol. From these considerations, it appears that methanol
is the logical candidate liquid.fuel for Task 2 experiments.
NATURAL GAS
Current commercial practices in residential space heating with natural gas are
reviewed, along with information on pollutant emissions and performance, to
assess practical means of converting the Rocketdyne/EPA optimum oil burner to
gas and its anticipated behavior in the integrated warm-air furnace.
Residential Gas Burners and Furnaces
Current state of the art was assessed by consulting a number of published
sources concerning design, installation, and operation (Ref. 12 through 14),
code and safety standard requirements (Ref. 15 through 17), and pollutant
52
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emissions (Ref. 18 and 19). Additionally, telephone conversations were held
with several knowledgeable people in the industry, and equipment brochures
were obtained from several manufacturers (Ref. 20).
New Construction. Practically all newly constructed warm-air gas furnaces
use atmospheric gas burners, which are so-called because the combustion air
is supplied at atmospheric pressure and is drawn into the burner and/or fur-
nace firebox by induction and natural draft. In typical atmospheric burners,
the natural gas is supplied at a regulated pressure, e.g., 3 to 11 inches
water column (WC), to an injection orifice (spud) which directs a single jet
of gas axially into a long mixing venturi. Atmospheric air is inspirated into
the venturi, through openings near the gas spud, and is mixed with the natural
gas to form a combustible mixture. That gas mixture is usually fuel-rich.
From the venturi, the primary mixture flows to one or more burner heads where
it is injected into a combustion space, ignited, mixed with secondary air,
etc., and burned. The motive force for the primary, fuel-rich gas stream is
simply the momentum of the injected gas jet. The burner, therefore, must pre-
sent only a moderately small resistance to the gas flow. As a result, the
final mixed-gas injection areas are relatively large, and burner designs com-
monly involve multiple port injection, continuous slot injection, etc., and
subdivision of the total flow from the venturi among two, three, or even more
burners is quite common. There are also some designs which use more than one
fuel spud and venturi assembly, although these are most often seen in larger
commercial and industrial installations.
The secondary air is usually not supplied through the burner, but enters the
firebox through openings around the burner and is caused to flow into the flame
zone by a combination of primary fuel jet induction, stack draft effect on the
firebox, and natural convection associated with the flame pattern and combus-
tion gas flow. Flow velocities are low and the pressure is essentially atmos-
pheric throughout the burner and combustion system. To not restrict the flow
of burned gases out of the firebox and to promote effective extraction of heat
from them, the primary heat exchanger is typically subdivided into contoured
sections keyed to the burner design.
The vast majority of warm-air gas furnaces have a standing pilot light outside
of the burner head to effect ignition when the burner is turned on. Typically,
the thermal input to a residential furnace pilot is about 5.28 x 10& J/hr
(5000 Btu/hr).
This standby consumption is about 4 to 6% of the main burner firing rates and
contributes to inefficient use of fuel. There is a developing trend toward
use of interrupted pilots that are turned off during standy.
It is apparent that there are substantial design differences between atmos-
pheric gas burners and gun-type pressure-atomizing oil burners, as well as
between the furnaces in which they are fired. It is simply inappropriate to
consider converting the Rocketdyne/EPA optimum oil burner and integrated fur-
nace into that type of system.
53
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Conversions From Oil and Coal. Several manufacturers make conversion gas bur-
ners for installation in existing oil or coal furnaces and hydronic boilers
to convert them to burn natural gas or propane. Many domestic conversion bur-
ners are of the atmospheric type, with venturi mixing of the gas and primary
air; nearly all of these are single-port burners of types designated "upshot"
and "inshot". In the inshot-type burner, the primary mixed gas stream flows
through a single horizontal mixing tube (downstream of the venturi) which
directs the gas stream against the flat or contoured side of a vertical metal
disc "flame spreader". A pilot flame is located near the flame-spreader and
a secondary air duct typically surrounds the mixing tube to force secondary
air into and around the flame zone. "Upshot" burners are very similar but
have a 90-degree bend in the mixing tube so that the primary fuel stream is
turned to flow vertically upward against the underneath side of a horizontal
flame-spreader disc.
There is a class of domestic conversion burners known as power burners. Indi-
vidual power burners may be defined broadly (Ref. 16) as: "A burner in which
either gas or air, or both, are supplied at pressures exceeding, for gas, the
line pressure and, for air, atmospheric pressure; this added pressure being
applied at the burner," and categorized (Ref. 16) as:
"a. Forced-Draft Burner. A burner for which air for combustion is
supplied by a fan ahead of the appliance.
b. Induced-Draft Burner. A burner which depends on the draft induced
by a fan beyond the appliance for its proper operations.
c. Premixing Burner. A power burner in which all or nearly all of
the air for combustion is mixed with the gas as primary air.
d. Pressure Burner. A burner which is supplied with an air-gas mixture
under pressure, usually from 0.5 to 14.0 inches of water and occas-
ionally higher."
These are general definitions, all of which do not -necessarily apply to resi-
dential-size burners. One manufacturer (Adams Manufacturing Co., Cleveland),
for example, makes forced-draft power gas burners in sizes ranging from
50,000 to 1,000,000 Btu/hr thermal input. The models up to 400,000 Btu/hr
input are venturi mixing designs, with forced-draft primary air fed Into the
venturi and forced-draft secondary air fed to the burner head. Larger models
employ a patented "vacuum mixing" principle whereby the gaseous fuel and all
of the combustion air are admitted separately to the upstream side of a per-
forated plate normal to the flow just upstream of the flame-zone. Thus, at
least for that manufacturer, premixing power burners are made only in sizes
larger than residential.
An exploded view of a residential-size, 237.4 x 106 J/hr (225,000 Btu/hr)
maximum thermal input forced-draft power gas burner is shown in Fig. 20,
reproduced from Ref. 21. An obvious correspondence can be seen between many
of its components (and its physical arrangement) and those of a typical gun-
type, pressure-atomizing oil burner. As noted above, this burner embodies
venturi mixing of primary air with the fuel within burner mixing tube 14 while
54
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ADAMS GAS
BURNER
MODEL HP-225B
Ln
Ui
21
REF
10
11
12
14
15
16
17
18
19
20
21
22
23
DESCRIPTION
Top Housing
Thermocouple
Pilot
Pilot Orifice
Spark Lighter
Transformer
Relay
Terminal Block
Air Door
Bottom Access Door
Slide Tray Assembly
Manifold
Pedests! (Not Shown)
Burner
Insulating Boot
Pilot Shield
Electrode
Automatic Valve
Pipe Nipple
Main Burner Orifice(Spec.Size)
Bottom Housing Assembly
Mounting Flange(Not Shown, Opt.)
Motor Blower Assembly
Figure 20. Exploded view of a forced draft power gas burner
(reproduced from Ref. 21)
-------
secondary air flows axially along the outside of that tube, within an approxi-
mately 4-inch-diameter blast tube, to be mixed with primary gases as they
are burned just outside the end of the mixing tube. This particular burner
uses an intermittent pilot light which is spark-ignited at burner startup and
is thermocouple-proved by a control circuit before the main valve is actuated.
The automatic valve assembly (18) fulfills several functions, viz., total
shutoff of fuel flow, activation of pilot fuel flow, actuation of main fuel
flow, regulation of fuel output pressure, and activation of the piezoelectric
spark lighter.
The pilot light on the Adams HP-225 B burner continues to burn until burner
cutoff. Many conversion burners, particularly older ones, still employ the
less desirable, continuously burning, standing pilot light. A somewhat dif-
ferent ignition system, used for example, on the Midco Economite Model DS5850
(discussed later), has no pilot light but provides direct spark ignition of
the main flame, which is proved by a solid-state electronic circuit by flame-
rectificaton by sensing of an imposed current between two sensor electrodes.
Otherwise, this Midcontinent burner is much like the Adams burner in that it
too uses power draft air, venturi primary mixing, and a multifunction main
valve assembly.
Installation of Power Gas Conversion Burners. As noted before, most residen-
tial-size power gas burners are intended for conversion of older coal- or oil-
fired heating systems to gaseous-fueled systems. Reference 17 delineates the
requirements for effecting safe and satisfactory conversions. Some of the
requirements are specific to hydronic and/or coal-fired units (e.g., water
coils in the firebox are prohibited, positive-closure latches on firing doors
are to be removed and/or replaced with spring-loaded safety catches, and
grates and ash pits are to be strengthened, sealed, insulated, etc., in speci-
fic ways). Other requirements are specific to oil furnaces and many others
are applicable to any conversion effort. Those which have some potential
applicability to converting the current prototype integrated furnace may be
summarized as follows:
1. Combustion air is to be supplied from outdoors if the unit is in
a particularly tight or fan-vented house. (This requirement is
obviously satisfied by the sealed air system.)
2. The conversion burner firing rate shall be matched to the firebox
size; inshot burners are stated to require combustion chamber
floor areas of 9.68 x 10^ m2 or more per 1.055 x 10~6 J/hr (1.5 in.2
per 1000 Btu/hr) thermal input, unless otherwise specified by the
burner manufacturer. (By this criterion, the 12-inch-ID cast fire-
box of the integrated furnace would be limited to a thermal input
of about 92.1 x 106 J/hr (87,300 Btu/hr) with natural gas or about
80% of its nominal 0.79 ml/s (0.75 gph) oil firing rate.)
3. With direct ignition systems, a minimum 30-second purge time is
required between burner start and main flame ignition. (The
present oil burner circuitry does not provide such a delay time.)
56
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4. Top-fired oil furnaces are not to be converted to gas. (Not
applicable)
5. Existing refractory firebox linings are to be removed down to the
level of the burner, unless that is the only thermal protection for
the steel shell. (Not applicable)
6. Movable dampers are not allowed in flue pipes.
7. A draft hood is to be installed in the flue pipe. AGA-suggested
designs for vertical and horizontal runs are illustrated in Fig. 21.
The pressure of the air surrounding the draft hood must be the same
as the combustion air supply pressure. (Although there is no mention
in Ref. 17 of barometric control dampers of the type normally used
in oil furnace installations, there are allusions to them in some
of the conversion burner manufacturers' installation manuals. Their
retention apparently is acceptable, so the integrated furnace's
sealed air system simultaneously satisfies this requirement and that
listed here as item 1.)
8. The furnace shall have a 93.3 C (200 F) air overtemperature switch.
(Same as integrated furnace)
9. There are a number of requirements regarding the fuel supply and its
controls. There shall be provided:
a. A manually actuated main shutoff valve
b. A gas pressure regulator
c. An automatic main control valve (usually combined with a
transformer)
d. A safety shutoff device, including sensors and electrical
circuitry
e. Ignition system components and controls, as appropriate
(With a pilot burner, for example, this would include a
pilot gas filter, a pilot shutoff valve, pilot supply tubing
and, perhaps, a manually actuated or automatic spark igniter.)
f. A pipe union between the manual shutoff valve and the pressure
regulator, and a vertical drip leg to collect small quantities
of moisture that might condense in the fuel line
g. Provisions for venting bleed gases from the pressure regulator
and/or diaphragm valves, as required (Gases heavier than air
must be vented outdoors while those lighter than air may be
vented outdoors, into the flue pipe (downstream of the draft
diverter), or into the combustion chamber next to a standing
pilot light.)
57
-------
Ln
00
-RIUCF OHNIHO-*
Tsble el Oil
Table, of Dlaii
0
1
2
55
72
94
11.5
US
I5S
175
197
222
247
70
9.5
10 a
120
139
156
175
ia a
207
222
07
10
1 5
1?
23
27
11
36
43
50
38
50
59
56
64
71
77
79
84
87
2.5
35
40
4.5
53
60
67
73
80
85
4.4
60
80
9 8
11 6
13 4
152
172
196
220
30
40
50
60
70
80
90
100
110
120
IJ
20
2J
25
29
12
IS
3.8
4 1
44
J
2.3
30
3.5
40
46
5.3
58
62
4.6
70
K
1.5
20
2.4
27
31
35
4.0
4J
46
50
t
3.2
4J
49
5J
6.2
7.0
7.7
8J
9.5
10.2
M
07
10
09
08
09
10
10
10
IS
17
6
a
10
12
14
16
18
10 20
II
12
"V.
13'/.
15
11% 16%
13% iay.
is zoy,
16% 21 %
22 18% MV,
24 20 25
-------
Many of functions b through e are now commonly built into an inte-
grated automatic main valve assembly (as illustrated in Fig. 20)
which does not produce bleed gases, avoiding problems with require-
ment g.
Air Pollutant Emissions
Natural gas has a solidly established reputation as a highly convenient, very
clean-burning residential, commercial, and industrial fuel. Its clean-burning
reputation, for the most part, is based on two factors: (1) most natural
gases contain very low concentrations of sulfur, fuel-bound nitrogen, and ash-
producing inorganic solids, and (2) most natural gas flames can withstand
considerable reduction in excess air levels from their normal design condi-
tions before a visible smoke is produced. In the residential-size range,
however, it appears that very few systematic and quantitative studies of
pollutant emissions have, in fact, been carried out. Although admittedly far
from an exhaustive search, an attempt to find pertinent reported data to
consider in this task yielded results from only two recent investigations, one
a laboratory study and the other a field survey.
Thrasher and DeWerth (Ref. 18) measured emissions from 38 different natural
gas-fueled, forced-air furnaces (made by 29 different manufacturers) in the
American Gas Association (AGA) Cleveland Laboratories. All except one of the
furnaces were tested under two different steady-state operating conditions:
(1) with the burner well adjusted to produce a stable, nearly nonluminous blue
flame, and (2) with the burner poorly adjusted to produce a stable luminous
yellow flame. Selected furnaces were tested further to determine parametric
effects on emissions of variations in burner-on time, burner firing rate,
circulating air temperature rise, and burner design concept (atmospheric
versus powered burners). Measurements were also made on several units to
determine emissions from standing pilot lights during furnace standby periods.
The main results of that study are summarized in Table 5, reproduced from Ref.
18. Average emissions are listed for 34 furnaces, 24 of which had multiport
atmospheric burners and 10 of which had single port burners (four upshot and
six inshot). Flue gas samples were taken downstream of the draft hoods; the
low values of sample C02 content reflect the air dilution accomplished by
those devices. Air pollutant species are reported as parts per million in
stoichiometric (no excess combustion air or dilution air) combustion product
gases. It is seen that single-port burners produced, on the average, slightly
lower emissions of CO, N02, and aldehydes, and significantly lower NO emissions
than did multiport burners. Generally similar differences between blue flame
and yellow flame operating conditions were observed with both burner types
although the latter condition, having lower excess air levels, exhibited
appreciably lower NO formation in the flame zone.
Two furnaces in this study were equipped with forced-draft power burners.
Emissions from one unit, whose burner was functionally similar to an atmos-
pheric single-port inshot burner, were all within the 95% confidence bounds
about the overall averages listed in Table 5. The other unit, built by AMANA,
utilized tneir HTM (Heat Transfer Module) concept. The HTM has a cylindrical
heat exchanger matrix surrounding a cylindrical burner screen through which
59
-------
TABLE 5. AVERAGE LABORATORY-TEST EMISSIONS OF ATMOSPHERIC
INJECTION FORCED AIR FURNACES (REF. 18)
Average
Overall
Multiport
burner
Single-
port
burner
Flame
Blue
Yellow
Blue
Yellow
Blue
Yellow
Sample ,
percent
C02
5.8 +1.0
6.0 +1.0
5.9+0.9
6.0 +0.9
5.5+1.1
5.8+1.1
Air-free, flue gas
CO
8.1 +2.6
208 +4
8.2 +2.8
201 +3
7.8 +2.1
225 +6
NO
88.8 +14.0
73.6 +16.0
94.0 +11.7
80.0 +10.0
75.0 +9.6
56.9 +17.6
concentration, ppm
N02
4.7 +2.4
9.7 +3.9
4.8 +2.5
8.8 +2.6
4.4 +2.2
12.1 +5.8
HCHO**
0.18 +0.14
0.60 +0.39
0.20 +0.14
0.62 +0.40
0.14 +0.15
0.60 +0.40
NOX emission
factor
lb/106 Btu*
0.098 +0.015
0.088 +0.014
0.104 +0.012
0.093 +0.010
0.084 +0.010
0.073 +0.014
Notes: *Sum of NO and N02 calculated as N02
**Total aliphatic aldehydes expressed as formaldehyde (HCHO)
The + value is the standard deviation of the average shown.
-------
the premixed, forced-draft, fuel-air mixture flows. The flame zone consists of
a myriad of tiny flame cones and a short radial flow path followed immediately
by quenching in the heat exchanger matrix. As a consequence, the measured CO
levels, around 100 to 130 ppm (air-free basis), were well above those listed in
Table 5 for well-adjusted burners, but also were well below the ANSI-specified
(Ref. 15) maximum of 400 ppm. Another result of the HTM burner design was a
substantial reduction in NOx emission levels. Emission factors of 0.018 and
0.013 pound NOx (as N02)/1Q6 Btu input were reported for burner firing rates of.
86.1 x 106 and 126.6 x 10& J/hr (81,600 and 120,000 Btu/hr), respectively.
These were on the order of 1/7 to 1/6 those of the more conventional gas fur-
naces; the dramatic reduction was attributed to (1) precise control of combus-
tion air allowing minimization of available oxygen in the flame, and (2)
immediate and rapid quenching of combustion products.
Kalika, Brookman, and Yocum (Ref. 19) measured air pollutant emissions from
chimneys of 100 natural gas heated homes in Connecticut. Their measurements
were conducted in two discrete sampling periods, each involving a different set
of 50 homes. The 1200 to 1400 ft2 floor area homes tested in the first samp-
ling period were built in about 1968 and were predominantly heated by gas-
fueled hydronic boilers. Homes tested in the second sampling period were
smaller (1000 to 1200 ft2), older (build in the late 1950's) and were pre-
dominantly seated by gas-fueled forced air furnaces. All units were tested in
their "as is" operating conditions and, since burner conditions varied widely,
there were large variations in the measured emissions.
Average values of air pollutant emissions and their standard deviations for the
two sampling periods are listed in Table 6. Consideration of the averages
suggests that the emission levels for all pollutant species were higher in the
second sampling period than in the first. However, the variations were so
large that only the aldehyde, total hydrocarbons, and carbon monoxide emissions
were found to be statistically different between the two groups of data.
It is tempting to conclude from the data in Table 6 that gas-fired, forced-air
furnaces produce higher emissions than do hydronic boilers. There were, how-
ever, several other factors which prevent such a clear inference from being
drawn from the data, e.g.: (1) approximately 14-year-old furnaces are being
compared with approximately 4-year-old boilers, (2) burner firing times and
cycle periods were longer and much more variable for furnaces than for boilers,
and (3) flue gases from separate gas-fired water heaters were usually vented
through the same chimney as those from furnaces, and carbonaceous emissions
from water heaters were found to be substantially higher than from furnaces.
Air pollutant emissions data in Tables 5 and 6 are reported in different units.
It is instructive to convert them to comparable units and, to promote compari-
son with past published data, English units of measurement are used in these
three tables. This is done in Table 7, where the comparison basis is the
weight (in pounds) of pollutant species emitted per million Btu thermal input.
Several assumptions were made to perform the conversions, viz.: an "average"
natural gas has a higher heating value of 37.3 x 103 J/M3 (1055 Btu/ft3) at
STP and, when burned with stoichiometric air, produces 0.313 m3 (11.06 ft3) of
product gases; an "average" No. 2 fuel oil has a higher heating value of 45.32
J/kg (19,480 Btu/lb) and a density of 843.4 kg/m3 (7.04 Ib/gal); and, for the
61
-------
TABLE 6. SUMMARY OF RESIDENTIAL GAS HEATING SOURCE
SAMPLING RESULTS FROM REF. 19
Pollutant
Filterable
particulate
NOx(N02)
Aldehydes
(HCHO)
Total
hydrocarbons
(as CH^)
Nonme thane
hydrocarbons
Carbon
monoxide (CO)
No. of
tests*
94
87
81
73
25
88
Results from second
Average measured
lb/106 ft3
0.88
120.6
16.3
81.7
40.3
78.4
sampling period
emissions, Standard
gas deviation
0.98
97.0
17.6
65.8
53.9
62.2
Results from first
No. of Average measured
tests* lb/106 ft3
96 0.63
89 103.8
84 11.5
88 56.8**
— —
96 42.4
sampling period
emissions Standard
gas deviation
1.16
98.0
9.5
88.0
—
33.6
*Quest±onable tests and tests where furnaces were maladjusted were not included in computing averages.
**The six highest values of total hydrocarbon emissions have been deleted from the average because they
are much higher than the remaining 88 samples and are considered outliers.
-------
TABLE 7. COMPARISON OF AIR POLLUTANT EMISSIONS FROM NATURAL GAS AND OIL-FUELED RESIDENTIAL
SPACE HEATING SYSTEMS (UNITS ARE LBW/106 BTU INPUT)
M
Natural gas
Ref. 18 laboratory study
Pollutant
species
N0x (as N02)
CO
Aldehydes
(as HCHO)
UHC (as CH4)
Filterable
particulates
Smoke
(Bacharach
scale)
Tuned to
blue flame
0.098
0.005
1.3 x 10~4
nil
Not measured
Not measured
Tuned to
yellow-flame
0.088
0.138
4.3 x 10~4
nil
Not measured
Not measured
Ref. 19 field survey
First sampling
period
0.098
0.040
0.011
0.076
6.0 x 10~4
Not measured
Second sampling
period
0.114
0.074
0.016
0.077
8.3 x 10~4
Not measured
No. 2 fuel oil
Ref. 7 field survey
As found
0.143
0.057
Not measured
5.3 x 10~3
0.0175
No. 3.2
Tuned
0.142
0.031
Not measured
4.2 x 10~3
0.0160
No. 1.3
- Rocketdyne/EPA
integrated
furnace
0.057
0.028
Not measured
2.8 x 10~3
Not measured
-------
Rocketdyne/EPA, integrated furnace where only NO was measured, it was assumed
that NO constitutes 90% (volume) of NOX produced. A number of very interest-
ing comparisons can be drawn from the data in Table 7. Gas furnaces in the
field can be compared with those in the laboratory as well as with oil fur-
naces in the field (Ref. 7 ).
Carbonaceous pollutant emissions (CO, UHC, and aldehydes) were all consis-
tently higher from gas furnaces in the field than from well-tuned, gas-
fueled units in the laboratory. The UHC and aldehyde levels in the field
were on the order of two orders of magnitude higher thau in the laboratory,
while CO was on the order of one order of magnitude higher. The average CO
and aldehyde production by units in the field apparently increase with age.
This is probably partly caused by long-term neglect and gradual drift away
from well-tuned conditions. In particular, the CO data suggest a gradual
long-term migration of the average toward yellow-flame conditions. It does
not appear that such a trend can account for the higher levels of UHC and
aldehyde emissions observed in the field, however. It is conceivable that
these latter differences were related to the compositions of the fuels used
or to the mix of burner types employed, but insufficient information is given
in Ref. 18 and 19 to resolve this point.
An average of the average gas furnace NOx emissions is about 0.10 Ib NOX (as
N02)/10& Btu input. The individual averages differ from that by < + 14%
which is comparable with the scatter in the laboratory data (Table 5) and
smaller than the scatter in the field test data. Thus, the individual NOy
emission averages probably are not statistically different among the gas-fired
systems.
Turning now to the field survey data on oil furnaces, it is seen that: (1)
average NOX emissions were about 40% higher than the average NOx from 8as
furnaces, (2) average CO emissions were roughly comparable with those from
gas furnaces in the field, while (3) UHC emissions were an order of magnitude
or more lower, and (4) filterable particulates were about 1-1/2 orders of
magnitude higher than the averages for gas furnaces in the field. These data
suggest that, from an air pollution viewpoint, residential gas and oil fur-
naces do not differ greatly from each other except that gas is less prone to
produce smoke and filterable particulates.
The most significant air pollution difference between the Rocketdyne/EPA
integrated oil furnace and the average of those oil furnaces field tested is
its substantially (60%) lower NOX emissions. The 0.057 Ib NOx/106 Btu is
already 43% below the average NC^ emission level for gas furnaces. The possi-
bility of achieving even greater percentage reductions in NOX emission levels
by converting the integrated furnace to burn natural gas does indeed appear
to be worthy of experimental evaluation.
Gas-Fired Integrated Furnace System Testing
As stated earlier in this section, the objective of the testing effort of the
alternate fuels evaluation is to evaluate the capability of the integrated
furnace to operate on other relatively clean fuels, and not to reoptimize the
64
-------
furnace for these fuels. Therefore, modifications to the integrated furnace
system were kept to a minimum.
Feed System Modifications. Obviously, the gaseous fuel feed system must be
substantially different from the existing liquid fuel system. The approach
taken was to provide a separate parallel natural gas line to the furnace. In
conformity to the requirements of Ref. 17, the 1-inch steel pipe line had
a manual shutoff valve and a vertical drip leg near its terminus. A section
of flexible metal tubing connected the feed system to the burner's main con-
trol valve. The natural gas supply pressure was regulated to 10-inches of
water column at the burner valve inlet. The fuel used was obtained directly
from the local (Los Angeles) supply system. The Southern) California Gas
Company stated that an average heating value of 3.93 x 10& J/m3 (1055 Btu/
ft^) is maintained in the natural gas supplied in the Los Angeles area.
Burner Modifications. It was intended originally to utilize the optimum
oil burner as the foundation for the natural gas combustion system in the
integrated furnace system. This proposed modified optimum burner system is
shown schematically in Fig. 22 using the gas control devices from the Midco
DS5850 direct-spark power gas conversion burner. However, during the pre-
liminary evaluation of the air/natural gas mixing process with the as-yet
undetermined gas feed tube hole pattern in the optimum oil burner head, it
became apparent that a relatively involved analytical or experimental opti-
mization evaluation would be required to ensure a fair representation of the,
natural gas combustion. This, of course, was in conflict with the objective
and the scheduling of this task. This resulted in a selection of a commer-
cially available, state-of-the-art representative burner.
The selection of the commercially available burner was simple since most of
the evaluation had already been conducted in the selection of components
for the optimum burner conversion. The burner selected is a relatively ad-
vanced, gas conversion burner of the newly AGA-certified, efficient direct-
spark ignition category, i.e., no pilot flame. The burner is a Mid-Continent
Metal Products Co. (Midco) "Economite" Model DS5850 with capacitive discharge/
direct-spark ignition and solid-state control system. Figure 23 is a reprint
of the specifications page in the manufacturer's sales brochure (Ref. 22).
Gaseous fuel flow control, ignition, and flame monitoring are accomplished by
the combination of a Honeywell V845A combination gas valve and a Honeywell
S825C electronic control board. The combination valve serves three functions:
(1) backup manual gas shutoff, (2) gas pressure regulation, and (3) automatic
gas shutoff. Gas supply pressure can range from 6 to 13-1/2 inch water column,
and the valve's regulator will provide a constant outlet pressure. It is
preset at the factory for 3-1/2-inch water column outlet. Nominal fuel firing
rates are selected by putting orifice spuds with different orifice diameter's
in an orifice holder downstream of the valve. If intermediate firing rates
are desired, the regulator's outlet pressure can be adjusted.
The automatic shutoff portion of the V845A valve is under control of the S825 C
control board, which supplies current to the valve's electric operator. The
control board supplies an intermittent 19,000 V current to the spark ignition
electrodes and provides a 6-second "trial for ignition" period, after which
65
-------
Manual Shut-off Valve
Drip Leg
Safety Control Circuit &
Capacitive Discharge Spark Generator
(Honeywell S825C)
Electrode Wire
>N—4
Combination Pressure
Regulator and Safety
Shut-off Valve
(Honeywell V845A)
Static Disc
Gas
Orifice
Block
Optimum Head
Anti-Flashback Screen
Quiet Stator
Figure 22. Conversion of the low-emission optimum burner
to natural gas
-------
REMOVABLE 4.1/4" oo
•LAST TUBE
«-S/l«" 0. D. ALLOY
TELtSCOPING BLAST
TUBE EXTENSION
LOOSE 1/8" THICK ASBESTOS
FLANGE GASKET
DIA. K.O.
(FOR POWER SUPPLY)
AIR SHUTTER
ADJUSTMENT
BLAST TUBES REMOVED TOR
DIRECT INSERTION IN « Vl« ' I. D.
MINIMUM FURNACE PONT
SPECIFICATIONS
Maximum input capacity
BTU per hour
Minimum input capacity
BTU per hour
Minimum combustion
Chamber size
Gas pressure required:
Natural Gas ...
Propane Gas . .
MODEL DS5850
200,000
85,000
7"Wi11"li
7"H er 10" DIAMETER
5" to 13.5" WC
11" W.C.
Standard voltage
Flame Safety
Main burner ignition
Nozzle Less Biist
Diameter Tub«
4%-
Nozzfe
Lengtt, 2*"
120 VOLT 60 HZ
ELECTRONIC
DIRECT SPARK
With Blast Tube and
Tube Extension
V/S 4*,~
2'A" 3% to 5~
ECONOMITE DS5850 BURNERS SHIPPED WITH THE
FOLLOWING STANDARD EQUIPMENT:
• Direct Spark Ignition System with Electronic
Flame Safety.
• Silent Multi-Vane Blower with Resilient-Mounted
Motor
• Blower Safety Interlock—Prepurge.
• Transformer for Low Voltage Thermostat 2-Wire
Control System.
• Combination Main Automatic Gaa Valve with
Gas Pressure Reirulator and Main Manual Valve.
• Flanee Mount with Burner Blast Tube and Stain-
less Steel Blast Tube Extension.
Figure 23. Dimensions and specifications for the Midco DS5850 burner (Ref. 22)
-------
the flame must be proved for the run to continue. If the flame is not proved,
the system will lock out. If the flame is proved, the spark is terminated
and the valve remains open to proceed with a normal firing. Thereafter, if
flame-out occurs for any reason, the system goes through a new "trial for
ignition" period; failure to prove a flame on the reignition attempt causes
the system to lock out.
The S825C control board includes a solid-state electronic circuit for monitor-
ing (i.e., proving) the flame continuously. Based on the principle of flame
rectification, it requires a flame sensor electrode and a flame ground rod
immersed in a stable section of the burner flame. These two sensor components
are shown in Fig. 23 and appear like two crooked spark electrodes, and the
electrical resistive properties between them is monitored by the control
board.
Natural Gas Test Results. The Midco burner was mounted into the prototype
integrated furnace system and fired at heat input rates equivalent to 0.79
ml/s and 1.05 ml/s of No. 2 fuel oil. Table 8 presents the results of the
flue gas measurements of steady-state and 4-minutes-on/8-minutes-off cyclic
natural gas firings. The data denoted by KG* have been normalized to the
heating equivalent of 1 kg of No. 2 fuel oil, thus making them directly com-
parable to the prior oil-fired data obtained in this furnace system. The
heating values used are 52.4 x 106 J/kg (22,500 Btu/lbm) for natural gas and
45.27 x 106 J/kg (19,460 Btu/lbm) for No. 2 fuel oil. Examination of the
data in Table 8 reveals high carbon monoxide (CO) and unburned hydrocarbon
(UHC) levels indicating that the finned combustor designed for the oil burner
probably induces premature quenching of the natural gas/air combustion. No
improvements in CO and UHC are noted in the higher (1.05 ml/s equivalent oil)
firing rate tests, indicating that the overcooling of the combustion zone is
substantial, with no response to a 25% change in input.
The nitric oxide (NO) concentrations are generally lower than the levels meas-
ured in the optimum oil burner experiments. However, if the combustion zone
temperatures were increased to promote complete combustion, i.e., satisfy the
CO < 1.0 g/kg and UHC < 0.1 g/kg criteria, the NO emissions probably would
rise above the nominal levels produced by the optimum oil burner system.
It is important to note that this conclusion conflicts, in most part, with
the generally accepted statement that "gas is cleaner than oil". This turn-
around resulted from careful utilization of simple optimization criteria that
require no advancement in the state of the art of the oil industry.
However, the smoke emission results in Table 8 reveal an advantage of natural
gas over fuel oil. No smoke was detected throughout the wide range of test
conditions (SR = 1.16 to 1.94), even with the adversity of an overcooled com-
bustion chamber. Although natural gas/air combustion can produce smoke, the
burner used is a powered (air blower) gas burner and the added mixing energy
available (compared to a naturally aspirated burner) may be partly responsible
for the observed zero smoke readings even at the lower stoichiometric ratio
conditions. This no-smoke characteristic again allows great flexibility in
pollutant optimization development efforts.
68
-------
TABLE 8. FLUE GAS EMISSIONS RESULTS USING NATURAL GAS AS FUEL
IN THE INTEGRATED FURNACE SYSTEM WITH A MIDCO
MODEL DS5850 BURNER
KG* « HEAT EOUIV. OF I KG OF NO. 2 FUEL OIL
NET
RUN STOIC. C02 02 CO NO UHC CO NO UHC BACH. TFG
NO. RATIO X * PPM PPM PPM G/KG* G/KG* G/KG* SMOKE C
616 1.63 7.3 8.8 70 33 6 1.35 0.682 0.066 0.0 275
617 1.37 8.6 6.2 30 39 2 0.48 0.675 0.018 0.0 269
618 1.34 8.3 5.8 45 38 4 0.71 0.642 0.036 0.0 261 o
» H
8 619 1.P8 9.3 5.1 167 3*5 16 2.52 0.612 0.137 0.0 258 a
OT "*
£ 620 1.20 10.1 3.9 552 33 76 7.74 0.495 0.609 0.0 244 S
8 -J
& 621 1.15 10.2 3.1 >1600 27 700>21.50 0.389 5.374 0.0 234 .H
62? 1.28 9.3 5.0 139 38 7 2.08 0.609 0.060 0.0 247 £
o
ft
623 1.27 9.5 5.0 177 16 3 2.65 0.255 0.026 0.0 164 tj
u 624 1.P2 9.9 4.2 254 • 20 3 3.63 0.306 0.024 0.0 153 j?
«> H a
<£ 625 1.15 10.4 3.2 >l600 15 26>21.54 0.216 0.200 0.0 o,
626 1.51 7.7 7.6 80 21 2 1.43 0.401 0.020 0.0 167
627 1.94 6.0 11.0 266 19 100 6.18 0.473 1.327 0.0
628 1.63 7.5 9.1 105 31 13 2.03 0.642 0.144 0.0 264
630 1.47 8.5 7.7 65 29 3 1.13 0.539 0.030 0.0 245
21.73 0.349 8.537 0.0 234 *•
en S
634 1.26 9.9 5.0 355 40 70 5.25 0.633 0.591 0.0 245 ^
rH
635 1.P9 9.7 5.4 209 42 21 3.16 0.679 0.181 0.0 245 B
o
636 1.20 10.4 4.2 >1600 38 650 >22.48 0.572 b.219 0.0 242 ^
01
u
637 1.37 9.1 6.5 70 21 4 1.13 0.362 0.037 0.0 207 £
638 1.24 10.0 4.6 456 18 60 6.61 0.279 0.496 0.0 206 j;
•H 639 1.52 8.0 8.0 130 24 62 2.33 0.460 0.634 0.0 223 *•
CO rH
«— U
"*& 640 1.19 10.2 3.9 1259 15 220 17.55 0.224 1.752 0.0 204
641 1.25 9.5 4.6 177 15 30 2.60 0.235 O.?5l 0.0 207
69
-------
METHANOL
Past and Present Applications
Methanol has long been used as a portable and clean-burning fuel. It was
produced in the 19th century as a by-product from the destructive distilla-
tion of wood to charcoal and was used extensively for lighting and cooking.
Methanol as a fuel was gradually displaced in the late 1800's by kerosene
and other petroleum oils until it was reduced to a few specialty applications,
such as shipboard cooking and laboratory burners. A resurgence occurred in
Europe during the World War II era, when several countries blended both meth-
anol and ethanol with gasoline as motor fuels (Ref. 23). From then into the
1970's, its use as a fuel was again suppressed by the ready availability of
cheap natural gas and petroleum-derived liquid distillate fuels. Nonethe-
less, methanol was and is produced in substantial quantities for industrial
uses as a solvent and as a chemical feedstock. For example, over 4.54 x 106
m3 (1.2 billion gallons) of CHsOH were produced in the U.S. in 1975, mostly
from natural gas.
Recently, as a result of the 1973-1974 oil embargo, renewed interest has
arisen in producing methanol and/or mixed alcohols for mass distribution as
fuels (Ref. 24 to 26). Most attention has been given to their use as auto-
motive fuels, either straight or in gasoline blends. Distribution systems
established for automotive fuels usually are amenable to supplying fuels
for stationary combustion equipment as well, so methanol as a residential
heating fuel should be a natural outgrowth from any substantial automotive
application.
At the present time, methanol-fueled stationary heating systems are not
commercially available in the United States.
Air Pollution Emissions Studies
Residential-Sized Burning. A few experimental studies of burning methanol in
modified existing oil-fueled equipment have been reported. The work of Martin
(Ref. 11 and 27) is the most pertinent to residential-size equipment. Several
fuels — namely methanol, iso-propanol, a 50-50 mixture of those two alcohols,
No. 2 distillate oil, oil emulsions, and propane — were burned with a movable-
block swirl burner tunnel-fired in an adiabatic research combustion chamber
at a nominal 87,900 W (300,000 Btu/hr) input heat rate. The liquid fuels were
injected through commercially available pressure atomizing distillate oil
nozzles; nozzle sizes were varied inversely with the fuels' higher heating
values to maintain the fixed heat input rate. By comparison with No. 2 fuel
oil, the alcohol fuels presented no significant utilization problems. The
following conclusions were drawn from the results of the study (Ref. 27):
"1. Alcohol fuels produce lower emissions of nitrogen oxides than either
distillate oil or propane.
2. The NO emissions of alcohol fuels increase as the percentage of
higher alcohols increases.
70
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3. The low NO emissions for alcohol fuels appear to function from the
presence and level of oxygen in the fuel molecule, which can be
viewed as a diluent carried in the fuel. The operative mechanism
appears to be related to thermal effects of the fuel, latent heat
of vaporization, and/or decreased flame temperature; however, chemi-
cal effects cannot be totally ruled out.
4. In the experimental system, NO levels similar to those for methanol
(e.g., 65 ppm) could be attained for distillate oil and propane
with flue gas recirculation, and could be approached at high water
levels for distillate oil emulsions.
5. Based on the calculations, the use of methanol and an equivalent
water oil emulsion appears to impose a 6 to 7% increase in stack
loss compared to distillate oil with flue gas recirculation; how-
ever, it is anticipated that there will be some compensating factors
that can be designed into practical systems to minimize the losses.
6. The emissions of CO, UHC, and particulate from alcohol fuels were
essentially the same as those for the conventional clean fuels
tested.
7. From the technical standpoint, methanol appears to be a satisfactory
fuel for stationary combustion systems; however, the final commer-
cial feasibility will probably depend more on cost and availability
than on the ability to burn the fuel."
Commercial Boiler Burners. Duhl (Ref. 28) reported on a two-part study of
methanol as a boiler fuel. The first part was a small-scale demonstration,
on a boiler test stand used to evaluate fuels and burners, that methanol could
be a viable alternate fuel candidate. NOX emissions, on an equivalent flue
gas basis were about 1/4 of those from natural gas and about 1/10 of those
from NO. 6 residual oil fired in this device. The second part was a larger-
scale demonstration on a utility boiler rated at 193,000 kg/hr (425,000 Ib/hr)
steam. Only two changes were made in the fuel feed circuit: a centrifugal
pump was installed in parallel with the existing fuel pumps, to provide forced
recirculation from discharge to suction for startup; and, the burners' mechani-
cal atomizing tips were replaced. (Some peripheral-test tunnel experiments
were used to find the best-performing, steam-atomizing spray tips.)
The results showed that methanol may be handled just as any other liquid fuel.
It can be shipped and stored within the existing specifications for a number
of other fuels. Flue gas CO concentrations were less with methanol than with
either natural gas or residual oil. Spot analyses indicated negligible flue
gas concentrations of aldehydes, organic acids and unburned hydrocarbons
with methanol fuel. Smoke and particulates in the stack were nonexistent; in
fact, soot deposits from oil firing were gradually burned off by methanol
combustion products. NOX emissions with methanol were about 90% as high as
with natural gas, whereas, they were only 38 to 67% as high as with No. 6
oil (a smaller difference was measured as unit load was increased). No expla-
nation was offered for the relatively smaller impact of methanol on NOx emis-
sions from the boiler than from the small-scale test stand.
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Methanol-Fired Integrated Furnace Testing
The testing of methanol as an alternate clean fuel in the integrated furnace
proceeded in the most direct and simple approach. System hardware modifica-
tions were minimized with a "try-it-and-see" approach on operational require-
ments and precautionary modifications made only for safety reasons.
Feed System Modifications. The higher heating value of methanol is 2.27 x 10?
J/kg (9760 Btu/lbm). This is only half that of No. 2 fuel oil [~4.5 x 10'
J/kg (19,400 Btu/lbm)], so the firing rate with methanol must be about twice
that with No. 2 oil if the same thermal demand is to be satisfied. In a resi-
dential application, some enlargement of an existing oil storage and supply
system would probably be needed to accommodate methanol. At the least, a
larger fuel tank would probably be needed to avoid excessively frequent refill-
ing, however, existing local codes for residential storage of flammable or
combustible fuels may limit this preference. Also, a larger-diameter line from
the tank to the burner might be needed, depending on line length, to prevent
excessive line pressure losses from lowering the pump inlet suction pressure
into a cavitation condition with the more volatile methanol fuel. In the
Rocketdyne test laboratory, where the fuel tank is close to and elevated above
the burner, line size factors are not anticipated to be of any importance, so
the No. 2 fuel oil feed system was retained in its existing configuration for
use with methanol. The fuel used was anhydrous, commercial grade methanol.
Burner Modifications. Conversion of the optimum oil burner to methanol is
relatively simple. Unlike the liquid fuel flowrate, which we have just seen is
approximately doubled, the combustion air flowrate is only slightly changed due
to the stoichiometric air/fuel ratio being less than half that for No. 2 fuel
oil. As a result, the most significant burner modifications in this conversion
are associated with the liquid fuel circuit. Burner components which remained
unchanged included the burner body, the air fan, the quiet stator, the static
disc, the blast tube, the burner head, the ignition transformer, and the igni-
tion spark electrodes. The combustion air inlet draft control assembly and the
sealed vestibule door were removed as a result of recommendations from the
Rocketdyne Safety Officer to eliminate potential "pockets" for accumulating
methanol vapors. Additionally, a 20-second air purge, similar to a powered gas
burner cycle, was included in the start sequence to clear the combustion cham-
ber of any methanol vapors. This conservative safety procedure was used due to
the lack of existing operating safety codes for methanol as a fuel for station-
ary sources.
The specific gravity of methanol is 6.2% lower than that of No. 2 fuel oil so
that, for equal thermal inputs, the volumetric flowrate of methanol should be
2.11 times that of the No. 2 oil being replaced. The Sundstrand Model A fuel
pump on the optimum burner at the normal 6.9 x 10^ N/m^ (100 psig) output
pressure, has a maximum capacity that is about four times the nominal design
oil firing rate [0.79 ml/s (0.75 gph)] of the integrated furnace. Therefore,
the same pump was used with changes only in the ratio of pumped fluid to
bypass fluid. The only potential problem was increased wear of the pump's
moving parts caused by methanol not being as good a lubricant as distillate
oil. From the experiences reported in the cited literature on substituting
methanol for distillate fuels, it appeared that this was not a significant
short-term problem.
72
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The fuel spray nozzle was changed twice to match two oil furnace thermal
inputs (0.79 and 1.05 ml/s) for which substantial data exist for No. 2 fuel
oil in the integrated furnace. Rather than simply relying on the manufac-
turer's stated nozzle capacity, the fuel firing rate was measured while the
burner was firing and adjusted to the desired value by changing the nozzle.
Originally, a Honeywell RA890G/C7027A ultraviolet (UV) spectrum-sensing
safety control system was planned to be used in conjunction with a Q624
capacitive discharge ignition (GDI) system. The RA890G circuit is unique
in that it does not require that the UV sensor (C7027A) be downstream of
the UV-producing electrical spark. Instead, it is designed for use with
GDI systems which characteristically produce a spark of extremely short
duration, and the flame-generated UV light is evaluated during the relatively
long no-spark period. Therefore, the UV sensor could have been installed in
the conventional location in the blast tube. However, checkout firings
revealed that the burner's existing CdS flame detector cell was sufficiently
sensitive to the yellow-streaked blue flame produced in the cast-iron combus-
tor of the integrated furnace with methanol to use it for proving ignition
and the system was retained for this test series.
Methanol Test Results. Table 9 presents the flue gas emissions results of the
methanol experiments. Both steady state and 4-minutes-on/8-minutes-off cycl-
ical firings were made at heat input rates equivalent to 0.79 ml/s and 1.05
ml/s No. 2 fuel oil firing rates. Again, the emission concentration data have
been normalized to the equivalent heating value of a kilogram of No. 2 fuel
oil. The heating values used for this analysis were 45.27 x 106 J/kg (19,460
Btu/lbm) for No. 2 fuel oil and 22.68 x 106 J/kg (9750 Btu/lbm) for methanol.
The ratio of heating values is approximately two, however the ratio of stioch-
iometric air/fuel ratios (14.45/6.50) is also about two, resulting in a nor-
malization correction factor for methanol of approximately unity.
The CO concentrations, as in the natural gas tests, are unacceptably high.
However, in this case, there appears to be an improvement with increasing
firing rate. Furthermore, the UHC concentrations remain acceptably low,
giving an indication of only a mild condition of overcooling of the combus-
tion zone.
The NO results presented in Table 9 show extremely low concentrations of
this pollutant. As concluded by Martin (Ref. 27), the oxygen molecule in
the carbon/hydrogen structure (CH20H) may act as a diluent in the combustion
process. This, along with the formation of a relatively large amount of
water (~15 wt. % of combustion products) serve to inhibit the maximum tem-
perature in the combustion zone, resulting in lower thermal NO. Although
the combustion process in this test configuration was partially quenched by
the overcooled flame zone condition, the extremely low nitric oxide concen-
trations indicate that the NO readings would very likely remain below 0.5
g/kg* even at the higher combustion zone temperatures required for reducing
the CO concentrations (i.e., complete combustion).
The methanol results also show no smoke throughout the stiochiometric ratio
range tested (SR = 1.05 to 1.78). This nonsmoking characteristic displayed
in the results of this test series suggests great flexibility of low emissions
73
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TABLE 9. FLUE GAS EMISSIONS RESULTS USING METHANOL AS FUEL IN THE
INTEGRATED FURNACE SYSTEM WITH THE OPTIMUM BURNER
KG* = MEAT EOUIV. 0F I KG OF N0. 2 FUEL 011.
NET
RUN STOIC. C0P OP CO NO UHC CO N3 UMC BACH. TFG
NC. RATIO Z Z PPM PP1 PPM G/KG* G/-
-------
design criteria for methanol burners and combustors. Methanol, and perhaps
methanol/oil mixtures, appears very promising as a low polluting fuel.
ALTERNATE FUELS EVALUATION
Current priorities mandate more than convenience and price factors for deter-
mining the applicability potential of energy-related systems. Presently,
pollutant emissions and thermal efficiency are prime considerations, with
the influence of price not clearly defined in these times of rapidly changing
economics.
Pollutant Emissions
The pollutant emissions characteristics of natural gas, methanol, and No. 2
fuel oil have been presented in previous sections of this report. In summary,
there is a slight favorable bias for the No. 2 distillate fuel oil due to the
optimized state of the system for that fuel. All three fuels demonstrated the
likelihood that each could be optimized to release relatively comparable car-
bonaceous emissions of CO <_ 1.00 g/kg* and UHC £ 0.10 g/kg* presently imposed
on the oil fired integrated furnace system.
Both natural gas and methanol demonstrated a lower smoke emissions advantage
over No. 2 fuel oil. Quantitatively, this apparently large advantage is
actually small since the smoke emission in the oil-fired integrated system
has been minimized to acceptable levels at favorable operating conditions
(SR = 1.20) where only negligible gains in efficiency (<1%) could be further
realized. However, the advantages offered in design flexibility can result
in very saleable, compact, and efficient furnace configurations; whereas, in
oil-fired systems, geometric variations are limited by strict requirements
defined by smoke emissions.
The NO levels from the stock natural gas burner are nominally equal to those
of the optimized oil burner. However, the NO emissions from the relatively
undeveloped, methanol-fired system may be approximately 40% lower than those
with the other two fuels. This, combined with its no-smoke characteristic,
make methanol a preferred candidate for low polluting fuel alternatives.
Efficiency
Due to the nonoptimized status of the natural gas and methanol systems, only
a pseudo-quantitative efficiency analysis can be undertaken here. However,
advantages and problem areas can be identified by this analysis for this fuels
evaluation. All three fuels appear to be capable of operation at 10 to 20%
excess air. This 10% span of operating conditions affects the thermochemical/
heat transfer processes, i.e., thermal efficiency, by less than 1% and, there-
fore, is of only minor consequence in this evaluation. The flue gas heat loss
is the limiting factor in maximizing efficiency in the noncondensing flue
systems presently in operation. For example, in a No. 2 fuel oil system, the
maximum achievable thermal efficiency is approximately 85%, limited by 15%
*Heating equivalent of 1 kg of No. 2 fuel oil
75
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flue gas losses. Approximately 9% of this loss is sensible heat of the flue
effluents, and the remainder is attributable to the heat of vaporization of
the noncondensed water vapor formed in the combustion process. Table 10 pre-
sents an evaluation of maximum obtainable steady-state efficiency based on the
differences in amounts of water vapor in the products of combustion of the
three fuels. This evaluation is based on prior experiences and analyses of
the thermal efficiency characteristics of No. 2 fuel oil systems. Column 4
lists the weight percent of water vapor in the combustion products at 20%
excess air. Column 5 relates the latent heat of vaporization to the fuel's
heating values. The final column combines that latent heat loss with a
sensible heat loss to arrive at an estimated maximum steady-state efficiency.
It was assumed that the heat exchangers would be optimized to result in equal
net flue gas temperatures of 222 C (400 F). The resulting estimates show that
an oil-fueled system is capable of a slightly higher thermal efficiency than
one fueled with natural gas, while significantly lower efficiency can be
achieved with methanol. This notable difference in methanol thermal efficiency
would require a minimum increase in energy input of approximately 8% by com-
parison with natural gas. Even so, the NO emissions from methanol would still
be significantly lower than those from either oil or gas burned in a furnace
at equivalent thermal demand.
TABLE 10. ESTIMATED MAXIMUM ACHIEVEABLE THERMAL EFFICIENCY BASED
ON THE INFLUENCE OF WATER VAPOR IN THE COMBUSTION
PRODUCTS OF THREE FUELS
Fuel
No. 2 Oil
Methanol
Natural Ga
Relative
stolchiometric
mixture ratio
1.0
0.45
s 1.04
Relative
heating
value
1.0
0.5
1.16
Wt. t
H20* In
flue gas
6.3
12.9
9.6
Latent heat of
Uncondensed water,
Z of fuel 'a HriV
6.2
12.0
8.7
Estimated
naxlmun thermal
nfflclency, Z*»
84.4
78.4
82.2
*SR - 1.20
"Assuming equal net flue gas temperatures of 222C (400 F)
Applications
As stated earlier in this section, the use of natural gas as a heating fuel in
this country is predominant (~ 58.5%), more than twice that of fuel oil
(~27.5%). The data presented in Tables 5 through 7 show that the present
natural gas emissions are approximately equal to the optimum oil burner emis-
sions, which are approximately 65% lower than the NO levels emitted by oil-
fired equipment currently in service. In simplified terms, the current total
NO pollutant emissions produced by oil-fired residential furnaces is ~33%
more than gas. Total conversion from oil to gas would result in a ~37%
reduction of total NO emissions from these stationary heating sources. How-
ever, this balance of energy sources is very strongly influenced by price and
availability, and conversions would be difficult to mandate solely on the
76
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basis of emission reduction. It appears more practical to approach and obtain
equal emissions reduction of oil-fired devices by equipment optimization, of
which only one of the options has been investigated in this study.
Due to the already low levels of pollutant concentrations from natural gas/air
devices, further emissions optimization would result in only incremental indi-
vidual improvements. For example, an apparently substantial reduction in NO
emission of 50% would in actuality be only ~0.3 g/kg* reduction in NO concen-
tration for a natural-gas-fired device. However, the net overall effect of
such an improvement would result in a substantial total improvement due to the
sheer number, approximately 38.8 million gas-fired, residential-heating
device's (Ref. 10), but it would be difficult to convince such a great number
of consumers to make financial sacrifices for individually minute pollutant
emissions effects with no consideration for payback. Therefore, future
pollutant emissions optimization efforts on natural gas devices should proceed
in a more aggressive manner and include efforts to eliminate latent heat flue
gas losses, i.e., condensing flue systems. This would offer consumers an 8%
savings in fuel consumption with its associated additional 8% reduction in
pollutant emissions, and some further undetermined reductions in emissions
resulting from the cleansing/solvent action of the liquid condensate in the
flue gases, i.e., dissolving of NO., scrubbing of particulates, etc.
The use of methanol as fuel for stationary heat sources is essentially nil in
the United States. The present method of production of methanol, using
natural gas as the hydrocarbon base, is ineffective in the overall effort of
conserving presently available, limited energy resources. However, other
options for the production of methanol are available that utilize replenish-
able materials, e.g., trees, refuse, etc., that make it a suitable candidate
as an alternate fuel. Further evaluation of the specifics and economics of
the methanol production cycle is beyond the scope of this study, and this
evaluation will proceed on the conclusion that methanol is an available
alternate fuel candidate.
The above emissions evaluation revealed that the NO emissions of an optimized
methanol system are significantly lower (on the order of 40%) than those of
natural gas or optimized fuel oil-fired devices, with an additional advantage
of lower smoke emissions than fuel oil. The laboratory hot-fire test effort
demonstrated the ease of oil-to-methanol conversion on test hardware. Actual
installed^ hardware would require a change of safety control hardware, probably
very similar to the type found on powered gas burners, with air purge cycles
included to reduce explosion hazards. Optimization studies could proceed in
two directions: investigating retrofit conversions, and exploring all of the
emission advantages of methanol in new equipment design configurations. The
NO emissions data presented in Table 9 resulted from a methanol-fired furnace
system in only a preliminary development stage, yet showing 80% reduction in
NO from the average existing oil-fired unit (Ref. 7). Although the exact
geometric dimensions were not finalized, the above methanol furnace did uti-
lize most all of the recommended low-emissions devices, viz., cooled firebox,
plug-flow burner head, and air pulsation suppressors. Most fireboxes in
existing oil-fired systems are of the uncooled type (firebrick or pyroflex-
insulated) to promote vaporization of the fuel oil, and are generally not
77
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amenable to direct flame impingement. Therefore, because of higher firebox
temperatures, the reduction in NO from retrofit methanol conversion burners
would not be as great, probably 50%, based on experience with No. 2 fuel oil
emissions testing. Although the maximum achievable thermal efficiency for a
methanol-fired system is 6% less than that achievable with fuel oil, a field
study (Ref. 7) shows that the average operating condition of existing oil-
fired equipment is more than 50% excess air. Methanol, with its essentially
smoke-free characteristics, could easily improve on this less efficient condi-
tion. This, coupled with careful matching with a heat exchanger might result
in competitive operating efficiencies for methanol-fired systems.
78
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REFERENCES
1. Dickerson, R. A. and A. S. Okuda: Design of an Optimum Distillate Oil
Burner for Control of Pollutant Emissions. EPA-650/2-74-047, Final Report
on Contract 68-02-0017, Rockwell Int'ernational/Rocketdyne Division,
Canoga Park, CA, June 1974.
2. Combs, L. P. and A. S. Okuda: Residential Oil Furnace System Optimiza-.
tion-Phase I. EPA-600/2-76-038, Phase Report on Contract 68-02-1819,
Rocketdyne, Canoga Park, CA, February 1976.
3. Combs, L. P. and A. S. Okuda: Residential Oil Furnace System Optimiza-
tion-Phase II. EPA-600/2-77-028, Phase Report on Contract 68-02-1819,
Rocketdyne, Canoga Park, CA, January 1977.
4. Combs, L. P. and A. S. Okuda: "Design Criteria for Reducing Pollutant
Emissions and Fuel Consumption by Residential Oil-Fueled Combustors,"
Paper No. 76-WA/Fu-10, presented at the 97th ASME Winter Annual Meeting,
New York, NY, December 1976.
5. Peoples, G.: "Sealed Oil Furnace Combustion System Reduces Fuel Consump-
tion," Addendum to the Proceedings, Conference on Improving Efficiency
in HVAC Equipment and Components for Residential and Small Commercial
Buildings. Purdue University, Lafayette, Ind., October 1974, pp A66-A72.
6. American National Standard Performance Requirements for Oil-Powered
Central Furnaces. ANSI Z91.1 1972, American National Standards Institute,
Inc., New York, NY, June 1972.
7. Barrett, R. E., S. E. Miller, and D. W. Locklin: Field Investigation of
Emissions From Combustion Equipment for Space Heating, EPA-R2-73-084a
(also API Publ. 4180), Environmental Protection Agency, Research Triangle
Park, NC, June 1973.
8. Combs, L. P., and A. S. Okuda: Commercial Feasibility of an Optimum Res-
idential Oil Burner Head. EPA-650/2-76-256, Final Report on Contract
68-02-1888, Rockwell International/Rocketdyne Division, Canoga Park, CA,
September 1976.
9. Climates of the States, Vol. I, NDAA, U.S. Department of Commerce,
Washington, D.C., 1973.
10. Detailed Housing Characteristics, U.S. Census of Housing, Bureau of the
Census, U.S. Department of Commerce, Washington, D.C., 1970.
79
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11. Martin, G. B., "Environmental Considerations in the Use of Alternate
Fuels in Stationary Combustion Processes," in symposium proceedings,
Environmental Aspects of Fuel Conversion Technology, EPA-650/2-74-118,
U.S. Environmental Protection Agency, Research Triangle Park, N.C.,
October 1974, pp 259-276.
12. ^as Engineer's Handbook, (Fuel Gas Engineering Practices), The Industrial
Press, New York, N.Y., 1965.
13. ASHRAE Handbook of Fundamentals, American Society of Heating, Refrigerat-
ing and Air Conditioning Engineers, Inc., New York, N.Y., 1972.
14. ASHRAE Guide and Data Book: Equipment 1972, American Society of Heating,
Refrigerating and Air Conditioning Engineers, Inc., New York, N.Y., 1972.
15. American National Standard for Gas-Fired Gravity and Forced Air Control
Furnaces, ANSI Z21. 47-1973, American Gas Association, Arlington,
Virginia, April 1973.
16. American National Standard for Domestic Gas Conversion Burners, ANSI
Z21. 17-1974, American Gas Association, Arlington, Virginia, October 1974.
17. American National Standard, Installation of Domestic Gas Conversion
Burners, ANSI Z21. 8-1971, Americajn Gas Association, Arlington,
Virginia, December 1971.
18. Thrasher, W. H., and DeWerth, D. W. , Evaluation of the Pollutant Emis-
sions From Gas-Fired Forced Air Furnaces, Research Report No. 1503,
American Gas Association, Cleveland Laboratories, Cleveland, Ohio, May
1975.
19. Kalika, P.W., Brookman, G. T. , and Yocum, J. E., A Study on Measuring
the Environmental Impact of Domestic Gas-Fired Heating Systems, Final
Report, The Research Corporation of New England, Wethersfield, Conn.,
June 1974.
20. Directory of Certified Appliances and Accessories, American Gas Associa-
tion Laboratories, Cleveland, Ohio, and Los Angeles, California, July
1976.
21. "Power Burner Installation and Service Manual, HP Series," Form 310B,
Adams Manufacturing Company, Cleveland, Ohio, 1976.
22. "Economite Model DS5850 Gas Burner," sales brocure, Mid-Continent
Metal Products Company, Chicago, Illinois, May 1976.
23. Reed, J. B., "The Use of Alcohols and Other Synthetic Fuels in Europe
From 1930-1950," AIChE 80th National Meeting, Boston, Massachusetts,
Sept. 1975.
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24. Reed, J. B., "The Production and Use of Alcohols as Fuels," ACS Symposium
on the Future of the Rubber Industry, San Francisco, CA, Oct. 1976.
25. McCloskey, J. P., "Grow Alcohol as a Replacement for Gasoline," Energy
Sources. Vol. 2, No. 1, 1975.
26. Barney, B. M., "Methanol From Coal - A Step Toward Energy Self-Suffic-
iency," Energy Sources, Vol. 2, No. 3, 1975.
27. Martin, G. B., "Evaluation of NOX Emission Characteristics of Alcohol
Fuels in Stationary Combustion Systems," Joint Western States and Central
States Sections Meeting, the Combustion Institute, San Antonio, Texas
April 1975.
28. Duhl, R. W., "Methanol as Boiler Fuel," a CEP Capsule, Chemical Engineer-
ing Progress, Vol. 72, No. 7, July 1976, pp 75-76.
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APPENDIX A
CAST FIREBOX MATERIAL SELECTION
The major question to be resolved in designing a cast-formed, finned firebox
was selecting the material of construction. Consideration was given to two
materials, cast aluminum and cast iron.
The primary advantages of aluminum over cast iron are its lighter weight and
higher thermal conductivity. The weight savings of ~11 kg (24 Ibm) primarily
allows savings in furnace shipping costs, with only minor considerations for
lower cabinet strength requirements. A transportation cost study, based on
shipments of 20 furnaces from the Los Angeles area (shipping rates are approx-
imately 15% higher west of the Rocky Mountains) revealed that even at the
higher West Coast rates and a maximum distance of 2000 miles, a savings of
only about $4/unit would result from using the lighter-weight, cast-aluminum
combustor. Therefore, the weight savings of aluminum, while significant, was
not considered to be of overriding importance.
The higher thermal conductivity of aluminum is, in this directly impinging
flame and "continuous" combustion application, offset by its lower maximum
temperature limitations. The establishment of maximum temperature values is
a problem in itself in the Underwriters' Laboratories (UL) certification
process, as no cast aluminum alloys are presently listed in UL No. 296 (resi-
dential furnace standard) for use in high-temperature combustion gases.
Discussions with UL personnel revealed that establishment of their maximum
temperature guidelines is more of a historical rather than a metallurgical
process, based on their experience with the listed materials. This presents a
major hurdle for the aluminum combustor concept as UL has had no experience
with the candidate cast aluminum alloys (Al 319 and Al 356),nor did they have
specific recommendations for Rocketdyne to proceed in testing and assisting
in the establishment of new guidelines for these cast aluminum alloys. Thus,
proceeding independently, maximum temperature guidelines were estimated by
comparison of various metallurgical properties of the UL listed materials and
the candidate aluminum alloys. A maximum temperature of 260 C (500 F) was set
for Type 356 aluminum alloy as suitable for long life (>10 yrs) , and design
calculations proceeded from this estimation.
To maintain combustor temperatures at or below this limit, very large cooling
fins would be required, extending out approximately 0.064 m (2.5 inches) at
the rear of the combustor. The long length of the fins introduced a problem
of a large temperature difference between the base and the tip of the fins,
resulting in critical internal stresses in the relatively low-ductility cast-
ing alloys. The fins would therefore have to be segmented, resulting in
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approximately 10% greater combustor costs. This would relieve excessive
stresses in the combustor wall but would increase the likelihood of nonuniform
heat transfer characteristics.
Another problem area was the differential thermal expansion between a carbon-
steel adapter ring (to be attached to the steel heat exchanger) and the cast-
aluminum combustor. The tensile stress in the steel ring, at maximum opera-
ting temperature, is approximately two times the level that is considered safe
for 10° cycles. A more costly gasket-type joint would be required to absorb
most of the differential in radial growth to reduce stress. A question still
remaining unanswered was that of the effect of the direct flame impingement on
a cast-aluminum surface. Opinions were solicited from a variety of speci-
alists (e.g., Reynolds Aluminum representative, Rocketdyne Materials and
Processes personnel, and aluminum casting foundries) concerning the durability
of cast aluminum under these conditions, and a diversity of answers with no
concensus was expressed.
The design effort then concentrated on a cast-iron combustor design. The
maximum operating temperature allowed by UL is approximately 540 C (1000 F);
compared with aluminum, this provides much more design flexibility. In con-
trast to the long segmented fins required on a cast-aluminum combustor, a
cast-iron unit can incorporate continuous fins. A design with radially-
oriented cooling fins approximately 0.025 m (1.0 inch) in height was estimated
to allow parts of the combustor to approach a maximum of 340 C (650 F) , still
well below the 540 C (1000 F) UL limit.
Cast iron is very compatible with the concept of installing a steel heat ex-
changer attachment ring in the firebox casting mold so that it is integral
with the casting, and no special provisions are required. In fact, some
cast-iron/carbon-steel fusing is expected to occur in the casting process.
Thermal stress and cycle fatigue analyses of this joint supported anticipated
lifetimes exceeding 10 years without cracking.
A local iron foundry was visited to discuss the cast-iron combustor design,
and it was concluded that the basic design is very amenable to cast-iron
forming. Only minor detail changes were recommended and these were incorpo-
rated in the design drawings.
A summary of estimated costs of fabrication and installation of cast-aluminum
and cast-iron combustors, based on production of 10,000 units/year, is given
in Table A-l. The estimated aluminum unit cost of $60 each could possibly be
reduced by approximately 10% by the use of permanent molds for the low-
melting-temperature aluminum, or perhaps by die casting, depending on the
total projected production run. Thus, the 20 to 25% higher cost of using
aluminum might be approximately halved. This, coupled with the technical
problems and disadvantages attending the use of aluminum reinforced the selec-
tion of ca^t iron as the firebox construction material.
83
-------
TABLE A-l. ESTIMATED CAST COMBUSTOR COSTS
Cast aluminum Casting at 10,000/year $45
H-1.3 kg)
Segmenting fins + $5
Machining for mount holes + + $2
burner port
Gasket-type joint + $3
Mounting legs and face plate + $3
Assembly + $2
$60
Cast iron Casting at 10,000 year $40
(~22.7 kg)
Machining for mount holes + + $2
burner port
Mounting legs and face plate + $3
Assembly + $2
A Shipping cost at 1500 miles + $2
$49
84
-------
APPENDIX B
DATA TABULATIONS: PROTOTYPE FURNACE EXPERIMENTS
85
-------
4-MINUTE-ON/8-MINUTE-OFF CYCLE-AVERAGED POLLUTANT EMISSION CONCENTRATIONS
PROM THE PROTOTYPE INTEGRATED FURNACE WITH 0.025 M EXPOSED COOLING
PINS AND A 0.152 M BURNER BLAST TUBE
P'.'N ST0IC.
N3. RATIO
_i 25 1.19
<• •.•
^J KU
o -» >
2°5
||^
Hi — 1 3
u u o.
— >
t— o
— 3
0 £
26
27
28
29
30
31
32
33
1.27
1.36
1.24
1 .24
1 .24
1.24
1. 17
1.3*
C02
12.8
11.6
1 1.3
12.4
12.4
12.4
12.4
13.0
11.3
02
%
3.6
4.5
5.9
4.3
4.4
4.4
4.4
3.3
5.9
C0
PPM
30
25
20
25
27
25
25
71
35
M0
PPM
35
35
35
34
35
35
35
35
35
UHC
PPM
1 1
9
8
4
1 1
6
8
7
6
C0 N0 UHC BACH. TFG
PPM GM/KGM5GM/KGM GM/KGM SM0KE C
0.47 0.601 0.099 0.0 221
0.42 0.649 0.086 0.0 227
0.36 0.698 0.083 0.0 227
0.41 0.599 0.038 0.0 224
0.46 0.637 0.104 0.0 224
0.41 0.636 0.057 0.0 224
0.43 0.637 0.075 0.0 227
1.12 0.600 0.064 0.0 218
0.65 0.694 0.062 0.0 232
-------
APPENDIX C
DATA TABULATIONS:
INTEGRATED FURNACE
OPTIMIZATION EXPERIMENTS
87
-------
TABLE C-l
STEADY-STATE FLUE GAS TEMPERATURES AND POLLUTANT EMISSIONS
FROM A NEW LENNOX 011-140 FURNACE
NET WARM
RUN 5T0IC.
N3. RAT 13
^
3 ON
Jo
C oi
Sfl
»J R
13
S2
«£
J2
n5
Is
v< •
34
35
36
33
40
41
42
43
44
46
47
48
1.24
1.24
1.30
1.38
1.44
1.65
1.56
1.85
K34
1 .43
1.29
1.21
1.26
1.57
1.51
C02
Z
12.2
12.4
1 1.9
11.0
10.6
9. 1
9.8
8.1
11.2
10.7
11.9
12.7
12.1
9.9
10.2
02
I
4.3
4.3
5. 1
6.0
6.7
8.6
8.0
10.0
5.5
6.7
5.0
3.9
4.6
8. 1
7.5
C0
PPM
10
10
11
10
10
10
10
10
10
10
15
13
10
10
10
N0
PPM
104
106
102
92
89
69
74
52
91
103
1 11
118
121
106
1 10
UltC C0
PPM GM/KGM
2 0. 16
2 0. 16
2 0.21
1 0.18
1 0.19
2 0.22
2 0.21
2 0.25
2 0.18
0.19
0.26
0.22
0.17
0.21
0.20
N0 UHC
GM/KGM GM/KGM
1.853 0.019
1.880 0.019
1.888 0.020
1.816 0.010
1.831 0.011
1.642 0.025
1.679 0.024
1.408 0.029
1.73.9 0.020
2.109
2.053
2.040
2.183
2.399
2.332
BACH.
SM0KE
0.5
0.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.5
0.5
0.0
0.0
TFG AIR
C M3/S
256 .566
256
259
278
287
312
302
267
270
271
254
233
242
281
278 •
88
-------
TABLE C-l (Concluded)
NET WARM
RUN
N0.
p.49
0 CO
N S 50
o •
K 0
•o ^ 51
«J 0
o *-
•J *~l CO
-i 6 52
8" in
-j t6 c\ 53
a o
j
3
a
X
B !w 5"
SOU
3 «o355
H C X
SO O
56
H •»
00
rl
s
57
58
59
60
ST0IC.
RAT 10
1.33
1.29
1. 19
1. 54
1.24
1.24
1.31
1.32
1.33
1.34
1.35
1.34
C32
11.5
11.9
12.6
10.0
12.2
12.0
11.3
1 1 .3
11.1
11. I
11 .0
11.1
02
X
5.5
4.9
3.5
7.8
4.3
4.2
5.1
5.2
5.3
5.4
5.5
5.4
C0
PPM
10
10
10
10
10
20
20
21
15
10
10
10
N0
PPM
I 16
1 12
110
104
107
100
100
100
114
1 14
1 10
1 10
UI1C CO
PPM GM/KGM
0.
0.
0.
0.
0.
3 0.
3 0.
3 0.
2 0.
2 0.
1 0.
I 0.
18
17
16
21
16
33
35
39
26
18
18
18
N0
GM/KGM
2.198
2.060
1.869
2.316
1.898
1.764
1.868
1.878
2. 160
2. 172
2. 1 17
2. 1 1 1
UHC
GM/KGM
0.028
0.030
0.030
0.020
0.020
0.010
0.010
BACH.
SM0KE
0.0
o.o
2.0
0.0
0.5
3.0
1.0
0.5
0.0
0.0
0.0
0.0
TFG AIR
C M3/S
253 .566
242
232
286
252
219
229
235 T
260 .595
255 .708
269 .479
263 .566
89
-------
TABLE C-2
CYCLE-AVERAGED FLUE GAS EMISSIONS FROM THE INTEGRATED
FURNACE TESTED IN SIMULATED WINTER CONDITIONS
NET
RUN ST0IC. C02 02 C0 N0 UHC C0 N0 UHC BACH. TFG
N0. RATI0 X % PPM PPM PPM GM/KGM GM/KGM GM/KGM SMOXE C
61 1.21 12.8 3.9 25 39 3 0.40 0.685 0.027 1.0 253
62 1.16 12.9 3.0 30 39 3 0.48 0.656 0*029 1.0 248
o" 63 1.15 13.3 2.9 37 39 2 0.57 0.650 0.022 2.0 245
o
tH
1 64 1.24 12.6 4.3 23 39 3 0.39 0.700 0.028 1.0 254
£65 1.24 12.5 4.4 35 39 4 0.58 0.704 0.042 1.6 254
(0
.o' 66 1.25 12.4 4.5 35 40 5 0.58 0.717 0.046 1.6 257
H° 67 1.20 12.9 3.7 35 39 6 0.56 0.678 0.054 1.4 252
68 1.18 12.9 3.3 27 39 8 0.44 0.665 0.071 2.0 252
69 1.18 12.9 3.4 33 39 3 0.53 0.668 0.030 1.0 255
70 1.32 11.5 5.4 35 39 6 0.62 0.752 0.060 1.0 247
71 1.31 11.7 5.2 55 39 6 0.95 0.742 0.060 1.6 244
72 1.18 12.9 3.4 35 39 5 0.55 0.660 0.046 2.0 231
8 73 1.19 12.9 3.5 45 39 4 0.71 0.671 0.034 1.0 229
•g
3 74 1.39 11.1 6.3 47 39 18 0.89 0.791' 0.190 0.4 250
I
h 75 1.26 11.9 4.5 31 39 (3 0.54 0.706 0.129 1.8 241
.76 1.12 13.4 2.3 456 35 175 6.74 0.554 1.476 1.5 221
•
77 1.31 11.7 5.2 50 39 25 0.89 0.742 0.243 0.0 229
78 1.26 12.0 4.5 60 39 19 1.00 0.704 0.181 0.2 223
79 1.17 12.7 3.2 50 38 9 0.78 0.639 0.080 0.2 215
90
-------
TABLE C-2 (Concluded)
NET
RUN STOIC.
N0. RATI0
u
°o
i
4
"s
!
u
o
ID
.
co
II .
of
•
H"
i
80
81
82
83
84
85
86
87
88
89
90
91
92
93
1.19
1.16
1.13
I. 10
1.07
1.13
1. 15
1.30
1. 16
1.15
1.08
1. 19
1.16
1.34
C02
X
12.7
12.9
13.2
13.3
13.8
13.3
13.3
11.7
13.0
13. 1
13.9
12.7
13.3
11.3
02
X
3.5
3.0
2.5
2.0
1.5
2.5
2.9
5. 1
3.1
2.9
1.7
3.6
3.0
5.6
C0
PPM
40
57
77
148
342
31
31
50
30
55
1499
25
50
55
N0
PPM
35
35
33
31
30
33
40
39
35
35
258
35
35
38
UHC
PPM
2
5
3
10
40
7
7
20
1
1
240
1
3
22
C0
GM/KGM
0.65
0.89
1.17
2.16
4.86
0.48
0.49
0.86
0.46
0.84
21.42
0.40
0.76
0.98
N0
GM/KGM
0.607
0.576
0.537
0.486
0.458
0.537
0.666
0.733
0.594
0.572
3.959
0.610
0.574
0.734
UHC
GM/KGM
0.022
0.044
0.026
0.083
0.325
0.060
0.061
0.197
0.009
0.009
1.959
0.009
0.026
0.224
BACH.
SM0KE
0.0
0.0
0.0
0.0
o.o
o.o
0.1
0.2
0.0
0.5
1.0
0.5
0.0
0.5
TFG
C
217
212
211
206
206
206
233
241
230
226
219
228
233
244
91
-------
TABLE C-3
CYCLE-AVERAGED FLUE GAS POLLUTANT EMISSION CONCENTRATIONS
FROM THE FIRST INTEGRATED FURNACE AT VARIOUS FIRING RATES
V
H
N
N
§
1"
«.
i
H
f
3
A
N
-4
f
3
X
•^
•*
3
RUN
N0.
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
ST01C.
RATI0
1.17
1. 16
1.34
1.23
1. 19
1.12
1.33
1. 10
1.26
1.20
1.14
1.21
1.15
1.11
1.57
1.29
C02
%
12.8
12.9
II. 4
12.4
12.7
13.3
11.3
13.8
12.0
12.6
13. 1
12.6
13.3
13.6
9.7
11.7
02
^
3.1
3.0
5.6
4.0
3.6
2.4
5.4
2. 1
4.5
3.7
2.6
3.9
2.9
2.3
8.0
4.9
C0
PPM
35
41
55
42
40
148
65
254
45
40
65
35
75
535
55
21
N0
PPM
36
33
38
39
38
35
40
38
40
34
36
33
34
33
40
39
UHC
PPM
9
4
16
13
11
15
24
30
16
10
8
5
5
70
22
4
C0
GM/KGM
0.54
0.64
0.98
0.70
0.63
2.20
1.15
3.71
0.75
0.64
0.98
0.56
1.14
7.90
1.16
0.33
N0
GM/KGM
0.612
0.552
0.742
0.694
0.651
0.565
0.773
0.601
0.730
0.581
0.583
0.578
0.563
0.530
0.919
0.731
UHC
GM/KGM
0.079
0.035
0.163
0.121
0.099
0.127
0.242
0.250
0.153
0.091
0.069
0.046
0.043
0.590
0.264
0.039
BACH.
SM0KE
0.2
1.5
1.0
1.8
0.1
0.3
0.0
2.5
3.0
2.0
2.5
2.0
1.2
2.5
0.0
0.0
Hbl
TFG
C
221
223
239
229
217
206
225
268
284
272
267
213
212
209
245
222
1.21 12.6 3.9 40 40 5 0.64 0.703 0.046 0.1 214
92
-------
TABLE C-3 (Concluded)
NET
fcU.M ST0IC. C02 02 C0 N8 UHC C0 N0 UHC BACH. TFG
N0. RATI0
111
112
113
114
115
« 116
I »»
g 118
f 119
S ,20
A
> l21
122
123
124
125
126
1.47
1.41
1.17
1.14
1.07
1.35
1.20
1.16
1.07
1.13
1. 14
1.35
1.21
1.11
1.17
1.09
X
10.6
II. 0
13.0
13.3
14.0
11.5
12.9
13.2
14.0
13.3
13.3
11.7
12.7
13.5
13.0
13.8
X
7.2
6.5
3.3
2.6
1.5
5.9
3.7
3.0
1.5
2.6
2.7
6.0
3.9
2.1
3.2
1.9
PPM
51
31
25
35
383
35
30
27
-1600
40
40
35
40
148
95
-1600
PPM
45
43
40
36
33
43
40
41
31
40
39
36
40
35
35
27
PPM
9
5
2
2
40
4
3
1
350
3
3
4
4
8
5
500
GM/KGM
1.02
0.60
0.39
0.53
5.44
0.63
0.49
0.43
-22.62
0.60
0.60
0.63
0.64
2. 17
1.47
-23.06
GM/KGM
0.958
0.870
0.672
0.595
0.510
0.834
0.694
0.686
0.471
0.656
0.644
0.751
0.702
0.564
0.581
0.418
GM/KGM
0.
0.
0.
0.
o.
0.
0.
0.
2.
0.
0.
0.
o.
0.
0.
4.
101
056
018
017
324
041
027
013
828
026
030
041
037
067
044
118
SM0KE
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.5
0.2
0.0
0.0
0.0
0.0
0.0
0.2
C
198
186
176
171
174
190
179
-0
167
176
181
178
179
172
174
166
93
-------
TABLE C-4. INTEGRATED FURNACE SYSTEM FLUE GAS POLLUTANT
EMISSIONS MEASUREMENTS TAKEN WITH A CALIBRATED
SMOKE METER
RUN
N8.
133
134
135
136
137
138
139
140
141
148
143
145
146
147
148
149
ISO
IS1
158
153
154
155
STOIC.
1.17
1.17
1.17
1.18
1.43
1.53
1.48
1.87
1.19
1.35
1.88
1.67
1.48
1.17
1.48
1.37
1.81
1.18
1.19
1.13
1.31
1.18
C08
I
13.8
13.8
13.8
13.0
10.
10.
in.
18.
18.
11.
18.
9.
10.
13.
10.
II.
14.
13.
18.
13.
II.
8
1
.8
0
8
3
0
1
8
0
7
3
3
3
6
1
5
18.7
08 C0
X PPM
3.3 40
3.3 40
3.3 40
3.5 30
6.7
7.8
6.5
4.7
3.6
5.7
4.9
8.9
6.
3.
6.
6.
4.
8.
3.
8.
S.
3.
5
8
5
0
3
5
5
5
1
4
18
80
10
18
80
15
80
31
17
535
II
IO
80
HI 600
80
383
5
80
NB
pm
40
40
41
40
39
41
43
43
41
40
41
33
39
31
SO
43
4P
83
38
35
40
39
UHC
PPH
3
4
5
8
8
8
8
8
8
8
4
1
1
180
1
500 1
8
30
1
8
NET
CO NO UHC BACH. TF6
PPH GM/KCM 6M/KGH CM/KCM SMOKE C
0.68 0.679 0.087 —2 819
0.68 0.679 0.035 —2 818
0.68 0.695 0.044 3.0 814
0.47 0.678 0.018 8.5 811
0.36 0.814 0.088 8.0 887
0.43 0.980 0.083 0.0 804
8 0.81 0.874 0.088 0.0 800
0.38 0.789 0.019 0.0 189
0.38 0.708 0.018 1.0 183
4.0 841
5.0 835
0.87 0.784 0.080
0.34 0.761 0.039
0.78 0.807 0.013
0.34 0.806 0.011
180 8.88 O.SIS 1.059
I 0.83 1.080 0.011 0.0 189
0.18 0.8*2 fi.S 841
0.38 0.785 3.0 846
500 h83.77 0.375 4.843 S.O
0.38 0.650 0.018 3.0
5.73 0.561 0.856 4.0
0.09 0.759 0.010 8.0
0.31 0.670 O.OIfl 4.0 847
CONFIGURATION
1.0-70° - A Nozzle
0.14m L Blast Tube
0.85-70° - A Nuzzle
0.14m B.T.
0.75 - 70° - A Nozzle
0.14m B.T.
1 1.0-90° - ,
> 0.14m B.T.
A Nozzle
0.75-90° - A Nozzle
0.14n B.T.
0.75-45° - A Nozzle
0.14m B.T.
1.0-70° - A Nozzle
1.0-70° - A.
Research Opt. Head
156 1.17 13.0 3.3 80 40
157 1.18 18.7 3.4 80 44
158 1.17 18.7 3.1 80 45
8 1.84 0.680 0.018 6.0 864
8 0.31 0.748 0.018 4.0 857
8 0.31 0.755 0.018 4.0 853
1.0-70° - A.
Res. Opt. Head
0.23m x 0.25m Plate
Under Combustor
94
-------
TABLE C-4. (Cont.)
NET
RUN
NO.
159
160
161
168
163
164*
165
166
167
168
I6«
170
171
172
179
174
I7S
176
177
178
179
ISO
181
188
183
STB 1C.
RATIO
1.17
1.26
1.19
1.19
1.80
1.17
1.17
1.46
1.88
1.88
I.3R
1.38
1.19
1.49
1.89
1.66
1.36
1.58
1.48
i.eo
1.19
1.81
1.18
1.13
1.85
C08
X
13.1
18.1
18.7
18.7
18.6
18.7
18.9
10.6
IP. 6
18.0
II. 1
11.5
18.7
10.8
11.7
18.0
11.3
10. 1
10.6
11.9
18.6
IP.6
18.7
13.3
1?.0
a?
I
3.3
4.6
3.5
3.5
3.6
3.3
3.3
7.0
4.0
4.8
6.e
5.3
3.5
7.3
4.9
4.S
5.9
7.6
6.5
3.6
3.S
3.9
3.3
P. 5
4.4
C0
PPM
90
80
40
30
eo
11600
»I600
• 80
100
40
8S
17
383
80
85
55
40
30
31
11600
30
30
40
831
17
NB
PPM
35
40
48
48
47
36
37
41
40
48
40
43
35
39
40
40
39
35
36
45
IS
15
IS
'16
UHC
PP«I
4
1
8
8
8
840
800
8
10
3
8
8
810
8
8
8
8
8
8
ISO
8
3
8
85
8
ce
G.1/KGN
1.40
0.33
0.63
0.47
0.33
184.88
>84.77
0.39
1.68
0.68
0.46
0.38
6.03
0.48
0.43
0.98
0.78
0.61
0.61
k8S.46
0.47
0.48
0.68
3.45
0.30
N0
GM/KGM
0.599
0.738
0.713
0.713
0.814
0.615
0.681
0.860
0.707
0.767
0.806
0.811
0.607
0.858
0.749
0.730
0.773
0.785
0.751
0.771
0.873
0.865
0.854
0.301
UHC
G1/KGM
0.035
0.010
0.018
0.018
0.018
8.187
7.077
0.088
0.098
0.089
0.081
0.080
1.887
0.083
0.080
0.019
0.081
0.083
0.088
1.364
0.078
0.028
0.019
0.813
0.019
BACH.
S"IBKE
5.0
3.5
6.0
7.0
6.0
4.0
5.5
0.0
8.0
e.o
0.0
0.8
3.0
0.0
1.0
1.5
8.0
0.0
0.8
6.0
4.0
4.0
4.5
5.0
4.0
TFG
C
846 '
851
833 '
«<
84| .
170
169
IB9
167
174
177
188
166 "
i
19- |
1
183
180
mt
196 -
196
198
831 -
847
839
843
CM-FIGURATION
•) 1.0-70° - A. Res
I Head. Static 01s
> .14m from Head
11.0-70° - A.
Res. Ppt. Head.
No Static Disc
0.75-70°-A,
Research Optimum
Burner Head
0.75-70°- A,
Res. Opt. Head.
Orlg. Draft
Flap Issy
)
/ 0.75-70°-A.
> Res. Cpt. Head.
/ No Quiet Stator
)
Complete Optimum
Burner for UL
Inspection
Opt.
95
-------
TABLE C-4, (Cont.)
NET
RUN
NO.
184
IBS
186
187
188
189
190
191
t
194
195
196
197
198
199
800
801
808
803
204
80S
806
807
S10IC.
RATIO
1.38
1.24
1.19
I.P4
1.33
1.10
1.84
1.19
1.87
1 1.16
1.17
1.88
1.88
1.86
1.13
1.80
1.89
1.33
1.83
1.14
1.19
1.19
1.85
1.87
CBS
1
11.6
12.8
12.7
12.3
11.5
13.6
18.4
18.7
18.0
13.1
12.7
11.9
18.4
11.9
13.1
18.6
12.0
11.6
18.4
13.3
18.9
12.8
12.3
18.0
08
I
5.4
4.3
3.5
4.3
5.3
8.0
4.3
3.6
4.7
3.1
3.1
4.8
3.9
4.5
2,5
3.6
5.0
5.6
4.1
2.8
3.5
3.5
4.4
4.7
C0
PPM
10
10
30
10
10
1099
10
IS
10
35
30
20
20
10
90
20
20
20
80
30
20
80
15
10
N0
PPM
4B
38
18
31
28
21
SO
41
41
40
43
48
45
46
45
45
54
52
54
SO
50
SO
50
SO
UHC
PPM
5
2
S
3
50
2
1
1
9
2
2
2
1
1
1
1
2
8
1
1
2
2
2
CO
GM/KGN
0.18
0.16
0.47
0.16
0.18
15.95
0.16
0.24
0.17
0.54
0.46
0.34
0.32
0.17
1.35
0.38
0.34
0.3S
0.33
0.4S
0.31
0.31
0.25
0.17
N0
GN/KGM
0.911
0.566
0.311
0.548
0.548
0.387
0.886
0.701
0.754
0.674
0.716
0.890
0.788
0.835
0.731
0.775
I.OOS
1.000
0.958
0.816
0.8 47
0.848
0.891
0.908
UHC
GM/KGN
0.050
0.019
0.047
0.030
0.415
0.019
0.009
0.010
0.079
0.018
0.019
0.018
0.010
0.060
0.009
0.010
0.020
0.019
0.009
0.009
0.018
0.019
0.019
PACH.
SMBKE
4.0
5.0
5. 5
2.S
I.S
6.0
3.0
3.5
2.0
8.5
3.0
3.0
3.0
1.5
3.0
2.0
2.5
2.5
3.0
S.O
4.0
4.0
1.5
I.S
TFG
C CONFIGURATION1
852 "\
1 0.041m Choice Ota.
045 l> Burner Head,
( Orlg. Draft Flap
84. J
248")
I 35° Swirl Vane4
8«5 7 Orlg. Draft Flap
232 j
256 *)
253 1 Nozzle at 0.0095m
\ from Exit
259 /
211 j
-0
256 7 Nozzle at 0.0191m
\ from Exit
853 /
259)
247 L Nozzle at 0.0238m
2SI J
««— Tried 1.0-45°-A. No Go
240 -\
242
\ 0.23m Wide Pyroflex
887 f Liner on Front 1/4
I of Conbustor
233 J
227 ")
/ Pyroflex Insert
233 \ 0.23m Wide on Front.
f 0.23m Ola on Bottom
238 )
96
-------
TABLE C-4. (Cont.)
NET
RUN
N0.
808
809
CIO
en
812
813
814
eis
816
817
818
819
880
821
882
883
884
ST0IC.
RATIO
1.38
1.30
1.81
1.16
1.09
1.14
3 1.13
3 1.81
1.15
1.80
1.33
1.33
1.82
1.19
1.34
1.83
1.18
COS
X
10.8
11.7
18.4
13.0
13.8
13.8
13.4
18.7
13.2
18.8
II. 5
11.4
12.3
18.9
11.3
12.5
18.8
02
X
6.0
S.I
3.7
3.0
1.7
2.7
8.5
3.8
8.9
3.8
5.5
5. 5
4.0
3.5
5.5
4.1
3.4
ca
PPM
10
s
5
10
85
10
10
80
90
85
80
10
II
15
10
11
10
N0
PPM
93
93
95
96
93
95
93
85
49
49
49
54
SO
49
49
50
50
UKC
PPM
1
1
1
3
3
3
4
4
3
1
1
1
1
1
1
1
1
C0
GM/KGM
0.18
0.09
0.08
0.15
0.36
0.15
0.15
0.38
1.37
0.40
0.35
0.18
0.19
0.84
0.18
0.80
0.16
N0
GM/KGM
1.838
1.786
1.688
1.583
1.433
1.539
1.490
1.458
0.806
0.844
0.935
1.043
0.874
0.839
0.939
0.876
0.844
UHC
GM/KGM
0.011
0.010
0.009
0.026
0.025
0.026
0.034
0.036
0.086
0.009
0.010
0.010
0.009
0.009
0.010
0.009
0.009
BACH.
SM0KC
0.0
0.0
0.0
0.7
7.5
2.5
4.4
0.1
8.0
6.0
4.0
1.5
2.5
3.0
I.S
8.5
4.0
TFG
C
866 ->
858 ,
/
844 |
1
884
827
203
816 J
8,8 -]
88,
(
834 '
826 -
"*
816 J
816 ~l
819 j
816 ]
1
CONFIGURATION1
. Optlmuni Burner
' in Stock Lennox
011-140 Furnace
0.23m 1,'ide & 0.23m Ola
Pyroflex Liner, Two
' 0.038m Wide Fences
at 1900
0.33m dla. Pyroflex
s on Bottom, Burner
Recessed 0.0159m
> 1.0-90°- A,
0.23m Dla Pyroflex.
Burner Recessed
0.0159ir
885 1.57 9.7 8.0 80 38
886 1.44 10.4 6.7 IS 49
887 1.88 11.7 4.8 17 50
888 1.88 18.4 4.0 854 40
I 0.48 0.865 0.018 0.0 169
1 0.89 1.019 0.011 0.0 176 I 0.75-70°-A.
2 0.31 0.918 0.019 0.5 168 7 SoKte"""""1
50 4.11 0.708 0.462 3.5
£89 1.33 II.S S.S IS 54
830 1.87 18.0 4.7 10 S3
831 1.18 18.8 3.4 120 46
838 1.46 10.4 7.0 10 58
833 1.40 II.0 6.3. 10 54
I 0.87 1.041 0.010 2.0 207
I 0.19 0.958 0.010 8.5 206
7 1.88 0.781 0.063 4.0 801
I 0.80 1.102 0.011 0.5 817
I 0.19 I.09S 0.011 I.S 818
0.75-70°jA at
">5534 N/mZ Oil
Supply Pressure
97
-------
TABLE C-4. (Cont.)
NET
RUN STB 1C.
NB. RAT IB
634 1.89
635 1.35
636 1.41
631 1.41
838 1.31
839 1.88
840 1.86
841 3 |.P3
848 3 1.38
643-3 1.89
844 1.85
64S3 1.69
846 3 1.50
641 3 1.40
848 1.51
649 1.48
850 1.89
851 1.85
858 3 1.88
653 1.81
654 1.44
655 1.38
CO 8
11.9
11.3
10.8
10.6
II. 5
18.4
11.9
18.0
10.1
11.1
18.0
1.1
9.8
10. 5
10.4
II. 0
11.9
18.6
18.4
18.0
10.6
II. 5
B8
X
5.0
5.7
6.4
1.0
5.1
3.9
4.5
4.0
5.9
4.9
4.3
1.1
1.1
6.1
1.7
6.7
5.0
4.5
5.0
4.7
5.4-
CB
PPM
IS
10
10
10
60
180
30
198
10
30
100
38
65
31
II
80
30
40
90
30
IS
80
NB
PPM
4S
41
SO
41
41
43
49
40
39
41
40
40
40
40
33
38
30
31
31
44
41
81
UHC
PPM
1
1
1
1
6
8
3
10
5
4
30
1
S
4
8
8
5
S
80
1
1
1
CB
CM/KG*
0.86
0.18
0.19
0.80
0.35
1.93
0.50
3.83
1.89
O.SI
1.65
0.15
0.50
0.60
0.84
0.38
O.SI
0.66
1.53
0.51
0.89
0.35
NB
GM/KGH
0.838
0.981
1.018
1.010
0.896
0.147
0.885
0.716
0.785
0.767
0.783
0.991
0.811
0.801
0.115
0.661
0.568
O.S5I
0.565
0.806
0.868
0.511
UHC
GM/KGM
0.010
0.010
0.011
0.011
0.080
0.014
0.089
0.093
0.058
0.044
0.883
0.091
0.057
0.043
0.083
0.088
0.049
0.047
0.194
0.010
0.011
0.010
BACH.
SM0KE
8.5
1.0
1.0
0.5
0.0
1.5
0.0
O.I
0.0
O.I
8.5
0.0
0.0
0.0
0.0
0.0
1.0
8.0
6.0
1.0
0.0
0.5
TFG 1
C CONFIGURATION1
194'
808
810
816 /
188 -^
173
178
144
151
ISO "*
148
164
157 y
196 "
187
175
171
149 ,
0.75-70°A at
5534 N/mZ Oil
Supply Pressure.
0.034IT Ola Choke
0.75-70°-A
0.034m Ola Choke
s 0.75-70°-A (Cyclic)
> 0.75-70°-A
Nozzle at 0.0238m
From Exit
/
198 ")
807 (
\ lefthand Q-Stator.
801 f 0.75-700-A.
Nozzle at 0. 0238m
8S63 1.30 11.1 5.0 31 30 4 0.65 0.554 0.039 0.6 115 )
98
-------
TABLE C-4 (Concluded)
NET
RUN STOIC.
NO. RATIO
857 1.53
8S8 1.39
8S9 1.88
8603 1.87
861 1.89
868 1.48
863 1.40
864 1 . 48
865 1.34
866 1.89
867 1.81
868 1.43
869 1.36
870 1.38
871 3 1.35
.
878 J 1.40
.
873 J 1.48
874 3 1.38
COS
I
10.0
11.0
18.0
18.0
11.7
10.4
11.0
10.4
II. 5
18.0
18.7
10.8
11.4
11.7
11.5
11.0
10.3
11.1
08
Z
7.7
6.8
4.9
4.7
4.9
7.8
6.3
7.3
5.6
5.0
3.9
6.7
5.9
S.4
5.9
6.4
7.e
6.8
CO
PPM
80
80
45
80
SO
80
85
II
II
18
40
10
10
17
10
10
10
10
NO
PPM
38
36
31
88
38
39
37
54
46
35
38
SI
SI
40
95
95
93
96
UHC
PPM
1
1
3
II
4
1
1
1
1
1
3
1
1
1
8
1
8
CO
GM/KGN
0.41
0.37
0.76
1.35
0.86
0.39
0.46
0.84
0.81
0.88
0.64
0.19
0>I8
0.38
0.18
0.19
0.80
0.18
NO
GM/KGM
0.853
0.733
0.566
O.SI6
0.705
0.843
0.756
1.147
0.886
0.659
O.S5I
1.046
0.998
0.767
1.836
1.905
1.975
1.908
UHC
GM/KGM
0.018
0.01 1
0.089
0.106
0.039
0.011
0.011
0.011
0.010
0.010
0.087
0.011
0.010
0.010
0.081
0.011
0.081
BACH.
SMOKE
0.0
O.I
8.0
8.1
8.0
0.0
0.0
0.0
0.5
I.S
3.0
0.0
0.8
8.0
1.8
1.0
0.7
1.6
TFG
C
179 '
167
168
137 "
151 •
164 .
197 '
177
178
168 <
193 n
189
M
840 '
850
858
844 _.
CONFIGURATION1
]
I 0.75-70°-A,
> Nozzle at 0.0238m
[ 45° Baffle Above
1 Ccnbustor
J
Same as Above.
Fired With -1819
Oil Stock
' 0.75-70°-A,
I 0.23ir Dla Pyroflex
/ on Opposing Wall,
Nozzle at 0.0238m
}
0.75-70°- A
> 0.23ir Dla Pyroflex
on Opposing Wall
Lennox K,
. Seventh Week
' Emissions
Evaluation
NOTES: 1. Unless otherwise specified, test configuration 1s: 1.0-70 -A oil nozzle recessed 0.0127m,
0.16m I blast tube. O.CBZ&n d1a static disc at 0.0826m from exit. 0.0381m choke diameter,
with quiet stator, new draft flap assembly burner fired Into cast-formed, finned combustor.
2. Smoke reading taken with leaky smoke pump.
3. Cyclic firing, 4 minutes on/8 minutes off.
4. 35° swirl vanes used for Runs 187 through 270.
99
-------
TABLE C-5
RUN STOIC. C92
NO. RAT 10 %
FLUE CAS POLLUTANT EMISSION CONCENTRATIONS FOR VARIOUS
OIL NOZZLE TYPES IN THE INTEGRATED FURNACE
02
%
S>75 1. 38 11.0 6. 0
P76 l.?7 12-0 A.7
C0 NO
PPM PPM
15
21
59
47
NLT
C0 N0 UMC PACH. TFG
PPM GM/KGM GM/KC-M GM/KGM SMOKE C
CONFIGURATION
0.23 1.169 0.010 0.0 192
0.37 0.858 3.0
2 1 0.75-70°-E
f CSclic)
17« I
o
o
P77 1.39 Il.n 6.0 11 53 0.22 1.043
P78 1.30 11.7 5.1 15 49 0.26 0.914
SAMPLING SYSTEM AND COMBUSTOR/HEAT EXCHANGER SYSTEM LEAK CHECKED
| . 3" 11.7 5.1 35 50
PR 1 1.25 1?. 1 4.4 ?7 49
0.6O 0.931
0.46 O.877
0.75-70°-V
(Seni-sclid)
0.75-70 -A
(Kollovr)
?S2 1.66 9.3 S.9
?83 1 - 37 1 1 . 3 6.0
PR 5 '. *
11.9 5.3
15
15
6PO
15
50
60
57
59
0.33 1.200 O.013 n.O P08
O.27 1.176 O.010 O.O 1R9
9.96 O.984 fy~>0t» 3.0 173
o.?6 i. i on n.mn i.n \v,\
0.75-70 -A,
Sealed
Observation
Port
(1) 0.23m DIAJIETER PYROFLKX INSULATION ON-OPPOSINT, WALL INSIDE CAST-FORMED COMBUSTOR
-------
TABLE C-6. FLUE GAS POLLUTANT EMISSIONS FROM THE INTEGRATED FURNACE
WITH THE FABRICATED STEEL, FINNED COMBUSTOR AND WITH THE
RESEARCH OPTIMUM BURNER HEAD
HUN STOIC.
NO. RATIO
PS 6
PB7
288
289
290
291
292
893
294
295 l
296
297
298
299
3001
301
302
303
304
90S
306
307
308
309
310
311
319
313
1 •
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1 •
1 •
| •
••
| •
1.
1.
1.
1.
1.
1.
I.
1.
1.
1.
1.
1.
?b
19
14
3P
72
41
22
P7
16
30
30
22
14
18
16
19
26
22
IB
20
?2
26
25
23
19
15
10
13
CO?
X
12.
12.
13.
11.
9.
II.
12.
12.
13.
II.
II.
1?.
13.
IP.
12.
IP.
II.
12.
12.
13.
IP.
12.
12.
12.
13.
13.
13.
13.
2
7
3
7
0
0
6
1
1
8
7
5
2
7
7
6
9
4
7
0
6
4
4
6
0
4
9
7
OP
Z
4.
3.
2.
5.
9.
6.
4.
4.
3.
5.
5.
3.
2.
3.
3.
3.
4.
4.
3.
3.
4.
4.
4.
4.
3.
2.
2.
2.
5
5
7
4
3
5
0
8
0
1
1
9
6
3
4
5
5
0
4
7
I
6
5
1
5
9
0
5
CO
PPM
10
1 1
40
10
10
10
20
IS
90
20
21
30
37
60
40
20
10
10
20
20
20
17
17
17
IB
PO
231
50
NO
PI'M
40
3B
35
40
35
4?
45
44
39
35
49
46
33
40
39
46
47
48
45
40
40
40
40
40
40
40
31
37
UIIC
PI'M
1
1
2
1
1
1
2
2
5
3
1
1
30
?
2
2
2
1
2
2
2
2
2
2
2
3
PR
4
NFT
CO N0 UHC BACH. TFG
PI'M CM/KG^ GM/KGrt GM/KGM SlOKE C
0.17 0.7P8 0.010 3.0 261
0.19 0.643 0.009 3.5 210
0.40 0.5S? 0.017 3.5 254
0. IB 0.758 0.010 S.O 266
0.23 0.878 0.013 0.0 204
0.19 0.860 0.011 0.0 19?
0.32 0.790 0.018 I.S 192
O.SS 0.809 0.019 0.0 192
1.38 0.654 0.044 3.0 193
0.34 0.647 0.030 0.0 175
0.38 0.914 0.010 0.0 184
0.48 0.803 0.009 0.0 184
0.57 0.540 0.253 4.5 184
0.94 0.683 0.018 1.0 183
0.63 0.662 0.018
CO'JFirURATIflN
1.0-70 • A
Nozzle
0.75-70-A
Nozzle
1.3 169
0.75-70 -A Noi!l«
, Burner 0.025 n inco
Conliustor
0.32 0.7B7 0.018 1.0 174
O.'l7 0.859 0.019 0.0 174
0.16 0.841 O.n09 0.0 174
0.31 0.766 0.018 1.5 174
0.32 0.693 0.018 2.5 239
0.32 0.710 0.019 2.0 244
0.30 0.729 0.019 1.5 PSO
0.30 0.726 0.019 2.5 251
0.29 0.710 0.019 2.5 249
0.30 0.686 O.OIR 3.0 248
0.30 0.665 0.026 3.5 246
3.36 0.483 0.232 7.0 240
O.V« 0.605 0.034 S.O ?«2
0.75-70 -> :.'ozfle.
Burner 0.050 n
into Ccnbustor
1.0-70 -A Nozzle
' lurner 0.050 n
Into Crnbuscor
1.0-70 -A Nozzle
3i.rner n.OJi n
Inco Ccrtuscor
1. Cyclic Firing. 4-mln-on/O-nln-off
101
-------
TABLE C-7. FLUE GAS POLLUTANT EMISSIONS FROM THE INTEGRATED FURNACE
WITH THE CAST-FORMED COMBUSTOR
NET
RUN STB 1C.
N0. RAT 10
314 1.13
315 1.16
316 1.21
317 1.29
318 1.?9
319 1.18
320 1.15
321 1.22
322 1.29
323 1.38
324 1.17
325 1.35
326 1.25
327 1.11
328 2 1.33
3292 1.43
3302 1.37
331 2 1.43
3322 1.56
333 1.84
334 1.17
335 1 . 08
336Z 1.41
337 2 l.?3
338 2 1.15
Cd?
I
13.6
13.0
12.4
11.8
11.8
12.9
13.3
12.4
11.9
II. 1
1P.9
11. 5
12.4
13.4
11.5
10.8
11.3
10.7
9.9
12.1
12.9
13.8
10.8
IP. 2
13.1
02
X
2.5
3.1
3.8
S.O
5.0
3.4
P. 8
4.0
S.O
6. 1
3.2
5.8
4. 4
2.3
5.5
6.7
6.0
6.7
8.0
4.2
3.1
1.7
6.4
4.0
2.9
CO
pm
40
20
n
IS
IS
20
30
20
17
IS
37
10
10
t 1600
10
5
5
5
5
20
30
1019
20
20
30
NB
pm
40
41
41
41
41
40
40
39
40
40
35
43
41
31
44
43
42
43
42
45
45
35
49
44
41
UHC
PPM
2
2
2
2
2
2
3
2
2
2
3
2
2
1000
2
2
2
2
2
3
3
60
2
2
CO
GM/KGM
0.60
0.31
0.29
0.26
0.26
0.31
0.45
0.32
0.31
0.23
0.59
0.18
0.17
123.54
0.18
0.10
0.09
0.10
0.10
0.33
0.46
14.58
0.39
0.32
0.46
NO
GM/KG1
0.652
0.682
0.710
0.769
0.760
0.685
0.663
0.692
0.750
0.804
0.597
0.840
0.739
0.490
0.846
0.883
0.833
0.805
0.956
0.803
0.754
0.552
0.994
0.777
0.633
UHC
GM/KGM
0.017
0.013
O.OIS
0.020
O.OPO
0.018
0.026
0.019
O.OPO
0.021
0.027
0.020
0.019
8.406
0.020
.
0.022
0.021
O.OP2
0.024
0.028
0.026
0.490
0.021
0.019
PACH.
S40KE
5.5
4.5
3.5
3.5
3.0
3.5
4.0
4.0
3.5
2.0
S.O
2.0
3.0
7.5
2.0
0.0
1.0
0.0
0.0
2.0
3.0
6.0
0.0
2.0
3.0
Tf G
C COIFiniRATION
241
246
?<9
255
t
0.18 r "!M<: 7
1.0-7C0-* '.-2Z
Draft - 5 ?a
1
}0. 18 n B.T.
1.0-70°-A.
Draft - 10 Pa
247
259
266
253
0.18 n B.T.
1.0-70°-*.
Draft - 20 Pa
\
260
257
245
266
263
266
274
284 y
250
242
244
274
264
»T
0.14 n B.T.
S O
' 1.0-70 -A
Draft - 22 Pa
> 0.14 n R.T..
l.C-70°-A.
Draft - 10 ta
102
-------
TABLE C-7. (COMTINlirn)
RUN
N8.
339 2
3402
34, 2
2
343
3442
3452
346
3472
348
349
350
351
352
353
3542
3552
2
356
5
357 2
358 2
35,2
360
361
362
363
364
365
366
367
368
3691
3701
STOIC.
KAT10
1. 15
1.??
1.42
1.37
1.67
1.5?
1.63
1.37
1.48
1.28
1.24
1.18
1.13
1.09
1.21
1.51
1.44
1.33
1.28
1.19
1.13
1.33
1.28
1.19
1.14
1.16
1.12
1.P8
1. 19
1.23
1.21
1.23
COS
z
13. 1
l?.5
10.8
11. 1
9. 1
10. 1
9.3
II.)
10.2
11.9
12.2
IP. 7
13.3
13.6
12.4
10. 1
10.6
11.7
12.0
12.6
13.3
11.6
12.0
12.9
13.4
13.3
13.7
12.1
12.9
12.6
12.7
12.4
OP
I
2.8
3.9
6.5
6.0
8.9
7.6
8.5
5.9
7.1
4.8
4.3
3.4
2.5
1.9
3.7
7.5
6.7
6.5
4.8
3.4
2.5
5.5
4.8
3.5
2.7
3. 1
2.5
4.9
3.5
4.1
3.8
4. 1
CO
I'WI
30
20
?0
20
20
20
30
?0
17
20
20
20
80
* 1600
30
17
18
28
18
25
209
IS
IS
20
1019
100
1339
20
25
20
31
25
NO
Pfrt
41
«b
45
45
40
44
35
44
45
42
41
41
40
31
41
45
45
49
43
41
38
50
SO
54
49
49
40
52
SI
5?
48
45
UHC
I'M
2
2
2
2
2
3
2
2
2
2
2
4
450
0
2
2
3
2
2
10
2
2
3
ISO
200
e
3
CO
GM/KGM
0.46
0.3?.
0.3B
0.37
0.45
0.41
0.66
0.36
0.36
0.34
0.33
0.31
1.20
*23.Cfl
0.43
0.36
0.36
0.53
0.32
0.39
3.12
0.26
0.25
0.33
15.30
I.S4
19.86
0.34
0.11
0.32
O.bl
0.-?
NO
01/KCM
0.67?
0.779
0.9P2
0.893
0.983
0.973
0.843
O.B69
0.955
0.769
0.730
0.694
0.654
0.480
0.715
0.989
0.936
0.975
0.784
0.695
0.622
0.951
0.921
0.909
0.794
0.813
0.649
0.958
0.871
0.915
0.829
0.795
UHC
CM /KG*
0.018
0.022
0.0?)
0.0? t
0.0?3
0.037
0.021
O.OP3
0.019
0.019
0.018
0.034
3.710
-.000
0.023
0.0??
0.03?
0.019
0.018
O.OSb
0.020
O.C19
0.027
I.2B7
1.695
0.018
0.0?8
PrtCH.
SnaKt
3.0
2.0
0.5
1.0
0.0
0.0
0.0
1.0
0.0
1.5
2.5
2.5
4.0
7.0
3.0
0.0
0.0
3.0
2.5
4.0
6.0
0.0
0.0
1.0
6.0
3.5
7.0
0.0
1.0
0.5
1.0
0.7
NCT
TIC
C CrNFICURATlON
P57
259
273
273
291
277
268 ""
254
265
257
25B
253
248
243
254 y
233
278
322
264
254
250
183
177
173
167
0.14 n Blast Tube
1.0-70°-A :.o:tlo
Draft - 5 fa
OrlRlnal "1819"
> 0.14 n B.T.,
1.0-70°-A.
Draft - 10 Pa
0.14 m B.T.
l.n-70°-A.
s. Draft - 10 Pa ,
Throttled on aux.
blower
n ii m R T
169 ^ J5';5-70H-Ai'
169
177
174
177
15*
Draft - 10 Pa
,54 J
NOTE. 1 4-nln.-on/B-nln.-off cyclir tlrlif
2. Supercli.irc.L-il
103
-------
TABLE C-7. (CONTINUED)
NET
RUN STOIC.
NO. PATIO
371
37?
373
374
375
376
377
378
379
3801
3,,1
33?
383
385
336
38?
338
389
390
391
39?
393
I.3P
l.?4
1.16
I.P5
1. 19
1.13
1. 1 1
1.17
1.21
1.09
I.7P
1.34
I.P2
1.18
1.13
1.10
I.P5
1.15
I.PP
1.14
1.31
1.54
CO?
X
11.5
IP.4
13.?
IP.?
12.8
13.5
13. 1
13.0
,?.6
13.8
IP.S
8.9
11.5
IP.4
l?.7
13.3
13.6
IP. 4
13.1
12.5
IP. 9
11.6
10. 1
P?
t
5.4
4.3
3.0
4.5
3.5
2.5
?.P
3.P
3.9
I.R
3.8
9.3
5.6
4.0
3.4
2.6
2. 1
4. 4
4.0
3.S
5.3
7.9
CO
PPM
18
PO
120
?0
25
456
> 1600
70
30
456
30
?0
17
?0
30
177
1019
20
40
?0
20
15
17
NO
PPM
47
50
45
50
SO
41
38
49
50
34
44
40
46
46
45
40
3R
50
49
49
50
50
47
UHC
PHI
2
P
6
2
2
30
1500
P5
3
1
2
2
3
10
70
?
3
2
2
2
2
CO
Gl/rfGI
0.33
0.33
1.84
0.33
0.39
6.80
SP3.49
1.03
0.43
6.57
0.43
0.46
0.32
0.3P
0.47
2.67
14. Hb
0.33
0.61
0.32
0.31
0.26
0.37
N0
G1/KG"
0.904
O.BS6
0.748
0.905
0.856
0.659
0.612
0.813
0.866
0.615
0.767
1.015
0.887
0.8 OH
0.766
0.657
0.601
O.S9O
0.807
O.H64
0.847
0.941
1.060
UHC
GM/^CI
0.020
0.019
0.052
0.019
0.01R
0.255
I2.5M3
0.206
O.OP7
0.013
0.020
0.019
O.OP7
0.036
0.583
O. 019
O.OP6
0.018
O.OPO
0.024
PACH.
n.o
0.0
2.5
0.0
0.0
3.5
9.0
2.0
0.5
3.0
0.0
O.O
0.0
0.0
1.0
3.0
6.5
n.o
2.5
n.o
1.0
0.0
0.0
TKG
175
172
169
172
169
169
164
167
168
147
150 /
•x
216
192
IRQ
177
174
172
176
173
176
176
13?
198
r 0.14 in Blast Tube,
0.75-70°-A NorzlP.
Draft - 20 Pa
0.14 n R.T.,
T 0.75-70-A.
Dtfft - 20 Pa
0,)A m B.T.,
r 0,75-70°-A,
Drrft - 10 Ps
104
-------
TABLE C-7 (Concluded)
NET
RUN
NO.
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
41 21
STOIC.
RATIO
I.S2
1.26
1. IB
1.10
1.15
1.33
1.34
1.12
1. 17
l.?3
1. 16
1.19
1.23
1.20
1.13
1.17
1.37
1.30
1. 16
CO 2
X
10.2
ie.o
12.9
13.6
13.8
11.3
11.3
13.4
12.7
12.2
12.9
12.6
12.2
12.6
13.3
12.8
11. 1
11.7
12.7
02
X
7.6
4.5
3.3
2.0
2.B
5.4
5. 5
2.4
3. 1
4. 1
3.0
3.5
4.1
3.6
2.5
3.?
6.0
5.0
3.0
CO
PI'M
IS
IS
21
139
31
II
17
90
30
20
30
20
20
30
148
41
20
20
50
NO
PCM
46
48
49
39
43
46
47
45
SO
SO
49
49
4B
50
40
46
SO
SO
40
UIIC
HHM
2
2
2
6
3
3
2
4
2
j>
2
3
2
2
8
3
2
2
3
CO
GM/KGM
0.32
0.27
0.34
2.02
0.49
0.21
0.32
1.34
0.46
0.33
0.46
0.32
0.33
0.4R
2.22
0.6S
0.37
0.34
0.77
NO
GM/KGM
1.001
0.866
0.824
0.6PP
0.703
0.881
0.9,2
0.726
0.833
0.880
O.BI2
0.842
O.B47
0.85S
0.654
0.774
0.986
0.927
0.673
UHC
GM/KGM
O.OP3
0.019
0.018
0.050
0.026
0.030
0.020
0.034
0.018
0.019
0.018
0.027
0.019
0.018
0.068
0.021
O.OP1
0.020
0.026
BACK.
SMCKF.
0.0
0.0
1.0
3.5
2.0
0.0
0.0
3.0
O.S
0.0
O.S
0.0
O.S
O.S
4.0
2.0
0.0
0.0
I.S
1FG
C COSriWRATICN
191 "*
176
169
164
164
1
167
162
159
162
159
159 f
V 32 0.600 c?ti,
0.1° 'm Rlast Tuhc,
0.75-70°-A 'lozzlc,
Draft - 10 Pa
Vv a » 0.800 m3/s.
n.ia'n B.T.,
0.75-70°-A,
Draft • 10 Pa,
Burner 0.025 n Into
Combusinr
•V
163
167
167
168
178
176
148
OrlRlnnl "1819" Oil
0.14 n B.T..
0.7S-70°-A.
Draft - 10 Pa
1. 4-mln.-on/8-nln.-off cyclic firing
2. SuperchjrKCil
105
-------
UNDERWRITERS LABORATORIES INC.
MJfTIV.«lrS «MI MMUKPIPPa II LIMB* i««l *
on indejiriuleut.iiot-for-pnijit organization testingftn public softly
July 19, 1977
MP3279
77NK3S79
Rocketdyne Division
Rockwell International Corporation
6633 Canoga Avenue
Canoga Park, California 91304
Attention: Mr. Paul Combs
Project Engineer
Subject: Preliminary Examination of Oil-Fircd Central
Furnace Incorporating a Sealed Coiri>ust ion System
Gentlemen:
This will report the results of our preliminary examination
of your oil-fired central furnace with a scaled combustion
system.
The central furnace supplied to us is identified as Node!
011-140 and this unit appears to be manufactured by Lennox
Industries Inc.. Marshalltoun. Iowa wiLh certain modifications
to the combustion chairi>er assembly along with addition of
components to provide the sealed combustion system.
The oil burner is of the forced draft pressure atomizing type
of conventional design except for the air inlet housing
arrangement, burner firing head and stator plate within the
burner fan housing. It appears this oil burner was manufactured
by the R. W. Beckett Corporation, Clyria, Ohio and carries
the Laboratories Listing Mark signifying that it was in
compliance with UL requirements prior to modification by your
company.
The modification of the furnace and burner is primarily to
achieve a scaled combustion system. This is accomplished by
delivering the combustion air supply through a 4 in. dia.
flexible duct from out door's directly into the burner compart-
ment of the furnace. An adapter is also provided to house
the barometric draft regulator within tho combustion air
supply so that no difference in pressure occurs between the
air external to the regulator and the combustion air supply.
-------
UNDEHWIlll F.RS LABORATORIES INC.
•
MP3279
Page 2
July 19. 1977
The furnace is intended for connection to a conventional
chimney for venting the products of combustion to the outdoors.
The combustion air assembly installed on the burner incorporates
a self closing combustion air shutter which, although adjust-
able, will close when the oil burner is de-energized.
The burner is intended for operation firing No. 2 Commercial
Standard Grade oil fuel and is an integral part of the oil
fired central furnace, special type. The appliance is an
upflow type furnace intended for installation on combustible
flooring and is to be equipped with a field provided and installed
warm air plenum and return air duct system.
The purpose of this examination, as mentioned to Messrs. Combs
and Nestlcrode during their November 19, 1976 Laboratories
visit, is to bring to your attention any obvious construction.
design or installation features which may not conform to the
applicable requirements in the Sixth Ed11.ion of the Standard
For Oil Burners. UL296, and Fifth Edition of the Standard For
Oil-Fired Central Furnaces. UL727. He are unable to comment on
certain features relative to installation, including routing
and termination of the Clue pipe and combustion air duct
because a copy of your operating and installation instructions was
not included with the central furnace.
The following comirents are based on a review of the oil burner
construction and all referenced paragraphs pertain to the
Standard For Oil Burners, UL296 unless otherwise specified.
1. The combustion detector mounting bracket is
formed over the edge of the burner fan housing dnd is not
mechanically fixed in position as required by Pars. 4.15 and
17.2. If a fixed position is not established tests will be
necessary in both the maximum forward and rearward settings
to determine conformancc.
2. Removal of the burner access panel of the furnace
is necessary prior to adjustment of the primary air damper
door. We question how Lhe propr air/fuel ratio is obtained
following replacement of the burner access panel. We refer
you to Par. 4.10 regarding this subject. We also note the air
damper adjustment provides minimum and maxinum stops which
limits the combustion air damper travel to 2 in. and 3/16 in.
maximum and minimum open travel respectively. To conform
with Par. 18.1 of UL727 the adjustable damper is to include a
stop at it's minimum setting which will provide sufficient air
for complete combustion at the minimum burner input. We
would not anticipate that complete combustion could occur
at this minimum air shutter setting with a main flame hourly
input of approximatley 1 gal per hour (140,000 Btu per hour).
Rocketdyne Conments and Actions
Planned for Field Test Furnaces
A fixed position Mill be established by drilling
and tapping a hole In the burner housing for a
cap screw.
For the field testing, the panel Mill be removed
to adjust the conbustion air, replaced to measure
the flue gas composition, removed again. If fur-
ther adjustment is required, etc. It Is not
planned to correct this minor inconvenience.
A screw stop will be added In the field to ensure
that each unit operates with no less than
stolcMometrlc air at an input of 0.7S gph.
Uncertainty concerning the effects of differences
among Installations on this setting makes It un-
desirable to ship the test units with this preset.
-------
o
00
UNDERWRITERS LABORATORIES INC
MP3279
Page 3
July 19. 1977
3. Sheet metal screws are provided at the top, left
and right side of the burner fan housing front section to
retain the draft tube in position. To conform with Par. 4.12
sharp screw ends should not come in contact with the operators
hand. As you know, access is required in this area for
removal and replacement of the oil burner firing head
assembly.
4. The draft fan microswitch is installed within the
inlet air housing and appears to function as an air-fuel
interlock control. The normally open switch contacts close
when the combustion air damper door opens, completing the
circuit to the combustion detector. From our examination we
find that when adjusted to the minimum air shutter setting
the switch contacts are open until the damper door opens at
which time the switch contacts close. When the damper door
closes, simulating absence of a combustion air supply the switch
contacts remain closed. It appears that there is not sufficient
door travel to permit the switch contact to resume the
normally open position.
5. Par. 4.16 and 17.4 include requirements covering
removal and replacement of the oil burner firing head assembly.
It was found that although the assembly was capable of being
replaced in it's intended position, this installation was not
readily accomplished. Also, during the several attempts to
restore the firing head in the draft tube deformation occured
of the No. 21 ga. Type 310 stainless steel vanes attached to
the inner surface of the burner nose cone, resulting in a
reduction of clearances between current carrying parts of the
ignition electrodes and adjacent grounded metal parts. This
construction docs not conform with Par. 17.4.
6. The access cover plate of the combustion air intake assembly,
through which the copper oil line passes to tho burner firing head
assembly, is provided with an elongated opening. This cutout
in the plate is not provided with smooth well rounded edges
and could cause physical damage to the tubing. This is not
in compliance with Par. 13.6.
7. The bottom section of the inlet air housing does not
incorporate an open drain and will allow accumulation of oil,
should leakage occur from the fitting within the housing. This
construction does not conform with Par. 6.2.
Rocketdyne Comments and Actions
Planned for Field Test Furnaces
Neither these screws nor their protrusions into
the blast tube have been altered from the stock
burner. No operational problems are anticipated.
so no action Is planned
This condition was also observed In the
Rocketdyne laboratory. It Mill be eliminated by
provision of the microswitch position stop (Item
2. above) which will ensure no lower than
stolchlonetric confcustlon air.
This potential problem can be averted by exercis-
ing a minimal amount of reasonable care. The
subcontractors' service personnel will be warned
to be careful not to distort the vanes and to
check their alignment with the electrodes before
completing reassembly of a disassembled burner.
No further action Is planned.
Each burner will be checked before shipment to
ensure that there are not burrs or sharp edges
which might penetrate the oil line.
A l/8-1nch-d1ameter hole will be drilled In the
bottom of the Inlet air housing.
-------
o
VO
UNDERWRITERS LABORATORIES INC.
MP3279
Page 4
July 19, 1977
8. The hinge material of the air intake shutter
is 0.125 in. dia. steel rod and does not appear to be of
a corrosion resistant material. We refer you to Par. 8.S
regarding material selection for this part of the assembly.
9. The furnace assembly and related parts supplied to
us for examination does not include a draft regulator.
Conventional oil fired central furnaces are to be connected to
a draft regulator unless Listed for use without one. Shipment
of a Listed draft regulator as part of Labeled appliances of
conventional construction is not required, however, due to the
sealed combustion system design of your heating appliance we
recommend that a Labeled draft regulator be supplied with this
furnace to assure that no difference in pressure occurs
between the combustion air supply and air in the vicinity
external to the regulator.
10. The oil supply tubing between the power operated oil
burner pump and the burner firing head consists of copper
tubing with aluminum fittings. To conform with Par. 13.6 the
tube fittings should be Listed. Presently we believe that all
Listed fittings are fabricated from brass, bronze,
stainless steol or plated carbon steel and are judged suitable
when used in combination with copper tubing. Copper tubing
with aluminum fittings should not be used due to possible
galvanic action which may cause leakage, unless we conduct a
special investigation to determine that this combination of
dissimilar metals are suitable for the application.
11. The thickness of the air shutter is 0.038 in. To
conform with Par. 8.4 sheet metal air shutters less than
0.0508 in. thick are to be properly reinforced.
12. The electrode assembly cannot be identified as being
a Recognized item. To conform with Par. 18.9 and 18.11 the
ignition electrodes should be Recognized and suitable for the
intended application.
13. The Recognized component White Rodgers Type 668-453
safety switch is used in conjunction with the Honeywell Type
C554A combustion detector. The suitability of combination
of these components has not been determined and, therefore,
should not be used. He recommend the combustion detector
Type 956 manufactured by White Rodgers be provided with the above
safety switch. He refer you to Par. 33.1.
Rocketdyne Consents and Actions
Planned for Field Test Furnaces
The mild steel hinge rod will not be replaced
for the one heating season test period unless
field conditions are found to be excessively
corrosive and result In sticking of the hinge.
A new UL-llsted barometric draft regulator will
be supplied with each test furnace.
(These fittings were parts of the stock oil burner.
Laboratory experience with the burner did not
suggest that problems would arise during the
{field test period, so no action is planned.
The air shutter Is small and subjected only to
light pneumatic loads from the coirbustlon air
flow so It Mill not be disassembled for what
seems to be unnecessary reinforcement.
The electrodes are the same ones supplied with the
stock burner. They have been shortened by about
2 inches. "*
The Mhlte-Rodgers Type 956 detector has higher
Impedance than the Honeywell Type C554A compo-
nent. Apparently as a result. It Is less sensi-
tive to flame light from this burner. In parti-
cular, spurious cut-offs were experienced with
the H-R detector on short cycle Interval restarts
when the firebox and burner head were still warm
and, presumably, the Initial flame Mas less lum-
inous than with a cold start. It Is planned to
go ahead with the Honeywell detector.
-------
UNDEHWT.ITERS LABORATORIES INC.
HP3279
Page 5
July 19, 1977
14. The plug provided in the burner fan housing to
route the air prover switch wiring into the burner junction
box could not be examinee! without major dismantling of the
burner. Please refer to Par. 25.14 regarding material type
and thickness of this plug.
15. Insulated conductors are routed from the air
prover switch into the burner housing without being en-
closed in conduit nor does the combustion air housing
constitute a raceway or electrical enclosure. This
construction does not conform with Par. 27.5 and 27.18.
16. The bushing provided in the plug through which the
insulated wires of the air prover switch pass cannot bo
identified. We refer you to Par. 27.20 through 27.22 regarding
this subject.
17. The micro switch bypass relay is installed on the
cover plate of the burner junction box and receives its power
from the 120 v incoming power supply. It does not appear that
the required minimum spacings through air and over surface
are provided as required by Table 30.1.
18. The American Zettler Co. relay, referred to in
Item 17 above, and 8 pin tube socket assembly are attached
to the top surface of the burner junction box cover. This
cover and relay are supported only by the wiring when the cover
is detached for access to the junction box. This construction
does not conform with Par. 27.4.
19. The air housing of the burner as well as the burner
draft tube are not bonded for grounding as required by Par. 34.1
and 34.2.
The following comments are made based on a review of the central
furnace construction and all referenced paragraphs pertain to
the Standard For Oil-Fired Central Furnaces, UL727 unless other-
wise specified.
1. The combination fan and limit control is partially
covered by the combustion air duct adaptor and filter box assembly.
The control cover is difficult to remove and following re-
moval the fan and limit adjusting mechanism is not readily
visible nor does it appear that this control is accessible
for replacement without the need for removal of the combustion
air filter box. This construction does not conform with Par. 6.3
and 19.4.
Rocketdyne Comments and Actions
Planned for Field Test Furnaces
A small rubber groirmet protects the wires where
they pass through a stamped, sheet steel plug.
Although rubber Is not listed In the cited
paragraph as a suitable material. It undoubtedly
vlll last for the field test period.
These control circuit (Z4V) wires will be tied down
to prevent them from being abraded due to the com-
bustion air flow blowing them about.
It's an off-the-shelf rubber gromnet which, again,
1s not expected to deteriorate during the field
test period.
The Incoming power Is Z4V. not 120V, so the required
minimum spacings are provided. The relay actuator
coll 1s supplied 120V via two non-adjacent pins.
which are also separated by more than the required
minimum spacings.
Only 24V control circuits are present in the air
housing and the draft tube connection has not been
changed from the stock burner. No problem is
anticipated, so no action is planned.
The filter box assembly will be removed to provide
'access to the fan and limit switch cover and con-
trol settings. This Is accomplished by unscrewing
three sheet metal screws; a minor Inconvenience
uhlch will not be corrected In the test furnaces.
-------
UNDERWRITERS UlBOHATOmES INC.
MP3279
Page 6
July 19, 1977
2. The fiberglass insulation located within the
circulating air compartment of the furnace could not be
identified. To conform with Par. 11.1 the insulating
material shoujd be Classified with a fire hazard classi-
fication rating as specified in this paragraph of the Standard.
3. The fan and limit control is located within the
combustion air filter box and the main furnace junction box
is directly below the filter box. Any moisture or water
within the combustion air duct will drip or run on the
conduit connected to the junction box top and will enter
the box to wet all electrical wiring. This construction does
not conform with Par. 20.1.
4. Two unused openings are provided in the left and
right side casing panels in the vicinity of the burner
compartment. Three nonmetallic plugs were taped to the
inner surface of the furnace casing. A plate or plug as
required by Par. 21.12 should be used to close unused openings.
5. The furnace marking appears to be portions of
that normally provided by Lennox Industries on their Labeled
central furnace. These include the model designation, firing
rate, draft, clearances and electrical rating as well as the
cautionary statement relative to protection of the combustion
chamber from chemical soot destroyers. When Listing is
established for your product the marking should be that which
is specifically indicated for your product. We refer you to
Sec. 61.
6. The wiring diagram appearing on the furnace casing
panel does not include all electrical components provided by
your company.
7. We question if the use of the combustion air duct
will cause condensation to form on the outer surface of this
pipe which, in turn, could cause wetting of live current
carrying parts within the furnace junction box or other
electrical enclosures within the unit casing. If this is
the case, the construction does not conform with Par. 20.1.
8. To adjust the fan and limit control setting it is
necessary to remove the control cover as indicated in Item 1
above under furnace construction comments. We note that
although the control incorporates push-in terminal connectors
for power supply wiring to the control, some portion of the
conductors are uninsulated and could permit accidental
contact with these high voltage parts. This construction does
not conform with Pars. 32.1 and 32.2
Rocketdyne Conroents and Actions
Planned for Field Test Furnaces
It Is Johns-Manvllle terra Felt Insulation, a
rock wool blanket Insulation with aluminum foil
jackets on both sides. JM rates It as with-
standing temperatures to 2300 F, which Is far
above the maximum of 850 F experienced by
neighboring components. No action.
A1r burner moisture will be avoided either by
Installing a mechanical de-mister 1n the Inlet air
line or by taking the combustion air from the top
of the sealed air plenum.
Plugs used will be those that came with the stock
furnaces which were modified to become the test
units.
Inappropriate labels will be removed from the test
furnaces and. specifically, none will be allowed
to remain from which It might be Inferred that
they are UL-llsted.
A separate control circuit schematic diagram will
be glued In the burner vestibule of each test
furnace.
A silicons sealer will be used to prevent external
moisture from being drawn Into the furnace In the
vicinity of the combustion air supply connection.
This potential hazard will be corrected by short-
ening the bare, uninsulated stub of each wire so
that Us Insulation Is properly socketed Into the
terminal connectors.
-------
UNDERWRITbRS LAllOIIATOniKS INC.
•
MP3279
Page 7
July 19. 1977
The following comments are based on a review oC the central
furnace construction when equipped with the scaled combustion
air system.
1. As mentioned previously, a copy of the installation
manual was not provided therefore, we arc not certain how the
combustion air supply duct is lo be routed from the sealed
air plenum to the outside. This complete air intake assembly
is to be provided as a component of the furnace.
2. If this appliance is to provide complete separation of
the combustion system of the fuel burning appliance from the resi-
dence in which it is operating the design of the appliance
should prevent operation when the burner access panel is
removed or the burner access panel is to be hinged in a manner
not likely to permit or invite its removal. An interlock
switch if provided for this purpose should automatically open
the circuit when the door or panel is opened and which will
automatically close the circuit when the door or panel is
closed. However, the interlock switch may be such that a
serviceman can manually close the circuit Cor servicing but the
switch will automatically return to its normal position
when the door or panel is closed, i.e., be in a position to
automatically open the circuit when the door or panel is
reopened, provided the interlock switch is wired in the power
circuit to the appliance or in the combustion-detector circuit
of the primary safety control.
A burner compartment of an appliance intended to conform to
the above requirements should include a warning marking which
can be readily seen when the door or access panel is open.
The warning is to be in contrasting colors and read as follows:
WARNING - This Compartment Must
Be Closed Except When Servicing
The word WARNING should be in 30 point (10.4 mm) and the balance
of the statement in 24 point (8.4 mm) Franklin Gothic type or the
equivalent.
3. The outdoor air entrance of the air intake assembly
will bo required as part of the appliance. Such assembly was
not provided for our examination during this review. For your
information we wish to advise that the air entrance is to be
guarded, shielded or located to prevent rain, snow, debris
and birds from entering. A screen, if used, is to have a
mesh not less than 1/4 in.
Rocketdyne Cements and Actions
Planned for Field Test Furnaces
The stated approach is unreasonable In that It
leaves too little latitude for field Installa-
tions 1n existing houses.
This Is a valid eminent but Interlocks will not
be provided 1n the test units because of the need
to remove the panel to adjust the combustion air
setting.
This warning statement Is appropriate and will be
used.
These recomnendatlons concerning the air Inlet
conform to the planned Installation method.
-------
UNDEKWRI1 CHS LAUORATOKIKS INC.
MP3279
Page 8
July 19, 1977
4. The design of the air intake for combustion air
and the path of the intake air should provide adequate
combustion air to the burner and adequate dilution air to
any draft regulator.
5. The flue collar ofthe appliance extends 3/4 in. above
the flue collector box and is so located that screws are pre-
vented from being used for mechanical attachment of the flue
pipe to the flue collar. We suggest this flue collar height
be increased to not less than 1-1/4 in. to provide a more
substantial flue pipe attachment.
From a review of the list of electrical and fuel handling
components sent to us with the central furnace we have the
following comments:
1. We could not identify the Sundstrand oil burner
pump Model B2VA-8216 as a Listed or Recognized power operated
pump.
2. The Honeywell combination fan and limit control L4046A
does not appear in our files as a Listed or REcognized device.
Possibly, thjs is a typographical error in the list of components
you provided and you intend to use the Type L40G4A which is
a Listed control.
3. The American Zettlcr Co. relay is a Recognized
Component, however, it is not used in accordance with the terms
of Recognition for this device. This Relay is intended for
use in secondary circuits supplied by .1 transformer winding
with a maximum available output of 200 va or with a maximum
potential of less than 100 v due to spacings between opposite
polarity parts. This relay does not provide the through air
and over surface spacings required by Table 30.1 of UL296.
In addition this relay is of the open type and should be
installed within a suitable electrical enclosure. The burner
compartment of the furnace is not a suitable electrical
enclosure for open type electrical components.
4. The Amphenol Type 49SS8 tube socket cannot be
identified as a Listed or Recognized device.
Rocketdyne Conments and Actions
Planned for Field Test Furnaces
This will be provided by using a 7-1nch-
dlameter air Inlet line.
The flue collar 1s unchanged from the stock UL-
llsted furnaces from which the test unit was
derived. No action.
It came on the stock burner and carries a UL-
listed label. Based on laboratory experience with
this pump, no problems are anticipated, so no
action is planned.
This was a typographical error.
Ignatlon Is Type L4064A.
The correct des-
The controlled circuit Is 24V. not 1ZOV.
fore, no action.
There-
No action.
-------
UNDERWRITERS LABORATORIES INC
MP3279
Page 9
July 19, 1977
The test work anticipated on this furnace design, incorporating
an unlabeled oil burner will be basically as indicated below,
however, this should not be construed as a final test program
as test results may indicated the need Cor additional tests
not originally anticipated. The burner tests are based on
the Standard for Oil Burners, UL296 (Sixth Edition) and Standard
for Oil-Fired Central Furnaces, UL727 (Fifth Edition).
Burner Testa
1. Combustion air failure - Par. 47.1 through 47.4,
UL296.
2. Undervoltage - Par. 49.1 through 49.2E of Standard
UL296.
3. Power interruption - Par. 50.1 through 50.4 of
Standard UL29G.
4. Ignition test, electric high tension - Pars. 53.1
through 53.6 of Standard UL296.
5. Electric high tension - Pars. 18.1 through 18.4,
Standard UL296.
Central Furnace
1. Combustion-Burner and Furnace - Pars. 38.1 and 38.2.
UL727.
2. Operation - Par. 39.1 through 39.3, UL727.
3. Limit Control Cut-Out - Par. 40.1 through 40.7,
UL727.
4. Continuity of Operation - Pars. 41.1 through 41.5
of UL727.
5. Temperature - Par. 43.1, UL727.
6. Continuous Operation - Pars. 44.1 through 44.6.
OL727.
7. Blocked Inlet - Pars. 45.1 through 45.5, UL727.
8. Fan Failure - Par: 46.1 through 46.11, UL727.
9. Blocked Outlet - Par. 48.1 through 48.9, UL727.
Rocketdyne Cooments and Actions
Planned for Field Test Furnaces
Except for the electric high tension and dielec-
tric strength tests, one specimen of the test
furnace was subjected to these various tests In
the Rocketdyne laboratory. The only negative
result was a potential overtemperature of a por-
tion of the control circuit wiring under reduced
warm-air flow conditions. As a result, higher
temperature wiring will be Installed In that part
of the circuit.
-------
UNDBItWIIITERS LAIIOIWTORIC9 INC.
HP3219
Page 10
July 19, 1977
10. Dielectric Strength-Par. 50.1 through 50.5,
UL727.
It is anticipated .that the total. cost for investigation and
test of the one model and style of central furnace, Special
Type, with a view towards Listing wjll be approximately
$7500.00. Provided conformance is obtained the oil burner
will be described as an integral part of the heating appliance.
Applications are not enclosed at this time on the assumption
that some time will be needed by your company to review the
heating appliance and incorporate revised construction to
obtain conformance with the items referred to above.
When you are ready to have us proceed with the test and
investigation please let us know and applications will bo sent
to you.
At the request of Mr. Combs during the April 12, 1977 telephone
conversation with the writer no destructive examination was
undertaken due to the intended use of this appliance for
field test. We do recommend, however, that this product be
reviewed to determine that proper operation is obtained once
available to you.
The furnace is being sent to your facilities in Canoqa Part,
California.
This completes the work undertaken based on our preliminary
examination of your central furnace incorporating a sealed
combustion air system under Project 77NK3579 and we have
notified our Accounting Department to prepare and invoice you
for the charges incurred.
For your information and guidance we arc enclosing a copy of
"Suggestions to Applicants" and "Information on Shipping
Samples to UL - Northbrook. "
Very truly yours. Reviewed hy:
HUGHES ' E. TOOMSALU
^Senior Project Engineer Associate Managing Engineer
Heating, Air-Conditioning Heating, Air-Condi tioning
and Refrigeration Department and Refrigeration Department
JH:jp
P.S. In the interest of advancing consumer product safety through
cooperation with the Consumer Product Safety Commission. UL is
by this notice simply calling attention to the provisions of
the Consumer Product Safety Act, and particularly Section 15,
if your product is one covered by the Act.
115
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APPENDIX E
FLUE GAS POLLUTANT EMISSION CONCENTRATIONS
FROM INTEGRATED FURNACE FIELD TEST UNIT 2
AT 0.79 ml/s (3/4 gph) FIRING RATE
RUN
N3.
476
477
473
479
430
43 1
432
433
434
435
436
437
ST0IC.
RAT I 21
CT
1. 16
1 .26
1 .33
1.43
1. 55
1.64
1 .45
1 .34
1.25
1.20
1. 19
1 . 15
C32
%
EADY-ST
13.2
12. 1
11.1
10.7
9.9
9 .3
10.6
11.5
12.3
12.7
12.9
13.3
- Cvellr
32
?,
3.0
4. 5
6. 1
6.7
7.9
3.6
6.9
5.6
4.4
3.7
3.5
2.9
?al 4-nrl
C3
PP.-1
30
10
1C
10
15
100
20
20
20
25
30
90
! n . on /
N3
PF'l
37
41
42
41
35
22
35
33
42
42
43
39
8-nHn .
lr-iC
FP'4
2
2
2
2
2
10
2
2
2
2
2
5
nff - -
C3
GM/XG'l
0.46
C. 1 7
0. M
0- 19
0.31
2. IP
0.39
0.36
0.33
0.40
0.47
1.37
M.3
GM/XG^I
0.622
0.745
0.342
0.355
0.77-7
0.513
0.746
0.741
0.757
0.723
0.736
0.650
me
GM/KGM
0.
o.
0.
0.
0.
0.
0.
o.
0.
c.
c.
o.
017
019
021
022
024
125
022
020
on
013
013
043
BAC-l.
SM34E
1 .0
0.0
0.0
o.o
0.0
0.0
0.0
0.0
0.0
0.0
0.5
2.0
NET
TFG
C
179
132
135
133
196
202
137
134
132
131
131
131
0.36 0.606 0.359 0.0 161
116
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APPENDIX F
SUMMARY OF DISCUSSIONS AT THE FINAL FIELD
TEST PLANNING MEETING, 7 JULY 1977
Phase II will be concerned, primarily, with field verification of six integra-
ted furnace units whose design was finalized and where operational and per-
formance characteristics were observed in the laboratory during Phase I.
Three of the integrated furnaces will be installed in homes in each of two
field test locales in the Northeastern U.S., and will be used as the homes'
primary space heating sources during the 1977-1978 winter heating season.
Based upon climatic, housing, and heating system comparisons among many
potential candidate cities,the Boston, MA, and Albany, NY areas were selected
as the field test locales. Subcontracts have been let to one furnace distri-
butor in each area to assist Rocketdyne in the selection of host homes,
installation of furnaces, provision of periodic inspection and emergency
services and, at the end of the test period, removal of test units and
restoration of the homes' heating systems to their former conditions.
To assist in the final stages of planning and preparing for field testing, a
meeting was held at Rocketdyne's main plant in Canoga Park, CA, on 7 July
1977. In attendance were the EPA project officer, a representative of each of
the subcontractors, and essentially all of the Rocketdyne employees directly
associated with the project. The objectives of the meeting were to discuss
the field testing thoroughly enough that all participants would understand
their own and each other's roles, that all incipient and potential problems
would be discerned and solutions found (or, at the very least, thought about),
and to provide the subcontractors with previews of the equipment which would
soon be shipped to them.
Several pages of information were arranged in outline form to serve as a dis-
cussion guide for the meeting. The discussions essentially paralleled the
outline, so the approach taken in preparing this summary was simply to expand
the material handed out at the meeting by inserting the results of the dis-
cussions. This process was aided by making a tape recording of most of the
meeting. In the ineterests of clarity, items discussed at different times are
combined herein under a single appropriate heading, peripheral and background
discussions which preceded agreement on certain topics are omitted, and a few
topics not in the original outline have been inserted.
Reference is made occasionally to the Statement of Work for the subcontractors,
which is reproduced at the end of this Appendix.
117
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AGENDA
FINAL FIELD TEST PLANNING MEETING
THURSDAY, 7 JULY 1977
"DESIGN OPTIMIZATION AND FIELD VERIFICATION OF
AN INTEGRATED RESIDENTIAL FURNACE"
Time Event
8:30 (AM) Arrival of EPA Project Officer and Subcontractor Personnel
8:35 Introductions - Dr. B. L. Tuffly's Office
8:40 EPA Objectives in Residential Emissions Program - B. Martin
8:45 Meeting and Program Overview - P. Combs
8:55 Depart for Santa Susana Field Laboratory
9:30 Tour of Furnace Assembly and Test Laboratory - A. Okuda
11:30 Return to Canoga Main Plant
12 (Noon) Lunch - Executive Dining Room
12:50 (PM) Detailed Discussions
4:40 Adj ournment
118
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LIST OF ATTENDEES
Name
Blair Martin
Joseph lorio
Ronald von Ronne
Bart Tuffly
Paul Combs
Allan Okuda
Larry Russell
Ronald Bartley
Function
Project Officer
President
Representative
Program Manager
Project Engineer
Research Engineer
Design Engineer
Purchasing
Representative
Organization
US Environmental Protection
Agency
Atlantic Heating'& Air Condi-
tioning Co.
Main-Care Heating Service
Rocketdyne Division,
Rockwell International
PROGRAM OVERVIEW
Objectives of field testing
• To demonstrate proof of concept
• Low-emission design criteria for burner and firebox
- Are applicable to residential space heating
- Are compatible with improved efficiency
• Measure steady-state, cycle-averaged, and season-averaged
efficiencies
• To test for a relatively long time period
• Over one winter heating season, document:
— Stability of emissions
_ Stability of efficiency
- Freedom from maintenance
119
-------
Approach to field testing
• Test furnaces in actual residences
• Two distinctly different climates
- Maritime (Boston)
- Continental (Albany)
• Variety among host residences
- Construction
- Age and insulation
_ Exposure
• Known fuel-usage history
f Get local help from furnace service company
• Arrangements with host homeowners
• Installation, emergency service, maintenance, removal
• Periodic inspections (monthly)
• Coordinate and go along on all Rocketdyne visits to hosts
• Rocketdyne will perform specialised measurements
• Mobile instrument laboratory for emissions
• Recording data loggers for efficiency
120
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TYPICAL INTEGRATED FURNACE
INSTALLATION IN NORMAL OPERATION
-------
NJ
NJ
TYPICAL INSTRUHfNTATION OF AN
INTEGRATED FURNACf UNIT
-------
Output from field testing
• Experimental results
• Steady-state and cycle-averaged emissions
• Steady-state and season-averaged efficiencies
• Operational history
• Stability of performance
• Installation versatility
• Maintenance requirements
• Documentation of results
• Formal phase report
• Design guide
• Summaries in trade journals
• Technical papers
• EPA contractors meeting
• Engineering societies, e.g., ASME, ASHRAE
Based mainly
on
Rocketdyne data
Based largely
on
Subcontractor data
123
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OVERALL SCHEDULE FOR FIELD TESTING
Work Items
Construction of Test Furnaces
Installation & Checkout
Performance Verification Tests
Restoration of Heating Systems
Documentation of Results
Subcontractor Data Submit tal
Draft of Phase II Report
Print Approved Report
1977
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1978
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/ This overall schedule is acceptable to all participants. Discussion centered on whether
June 1st is too early for considering the heating season to be over and for removing test
furnaces and restoring the former heating systems. The consensus was that that date's OK.
-------
SCHEDULE FOR TEST FURNACE
PREPARATION - SHIPPING - INSTALLATION - ACTIVATION
NJ
l/l
WORK ITEMS
This Meeting
TEST FURNACES (Unit Nos:O)
Completion of Checkout
Firings
Ship to EPA/RTP
Ship to Subcontractor
Received by Subcontractor
Installation & Checkout
Host Homeowner Selection
MOBILE LABORATORY
Rack Mount Instruments
Install Racks in Van
Drive Van Cross Country
Initial Emissions Measure-
ments & Install Fixed
Instruments
RI ACCOUNTING MONTHS BY WEEKS
JULY
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(5
)
AUGUST
Ret'd from UL
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SEPTEMBER
Delmai
Bos tor
-------
DISCUSSION OF SCHEDULE
1. Projected shipment of integrated furnaces to and receipt by subcontractors
appear to be timely and acceptable. Both subcontractors would like to re-
ceive all units in August so that they can have them installed before fall
weather turns cold.
2. Blair Martin was uncertain as to how testing the unit tentatively
scheduled to be in RTF the last week in July and the first week in August
would fit into their laboratory schedule. After he has investigated, we
will firm up whether that unit, a later one, or none will be shipped to
RTF for test before being sent on to a subcontractor.
3. Paul Combs will visit the subcontractors soon (tentatively, July 21 and
22) to review their candidate host homes and, together, to rank them in
order of preference. He will telephone on 18 July to confirm that both
subcontractors are ready for this step.
4. Rocketdyne needs the mobile laboratory instruments in their Canoga Park
laboratory, nominally through the end of August. The mobile van will be
driven across country (probably by Al Okuda) some time in early to mid-
September, so the initial detailed measurement of emissions and activation
of fixed instrumentation will not be possible until late September.
5. In the meantime, the subcontractors will have installed and activated the
test furnaces and each furnace may have been in use for several weeks be-
fore Rocketdyne's initial visit to begin the quantitative field test
measurements.
126
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HOST HOMES
Selection
• Procedure - Review Statement of Work for subcontractors
• Guidelines - Review Statement of Work for subcontractors
• Selection Criteria
V/ In addition to those criteria given in the Statement of Work, it
was observed that subcontractors should endeavor to select homes
in "safe" areas, i.e., those having low incidences of street crime,
and to select homeowners who are flexible enough not to be unduly
annoyed by minor inconveniences, unscheduled loss of heat, etc.
It was established that the host homes should be single-family
residences, as opposed to duplexes or triplexes, where more than one
family has access to the test furnace.
• Firing Rate (0.75 +0.1 gph)
y Rocketdyne has lowered the nominal firing rate to 0.75 gph to avoid
greater than No. 1 smoke when the burner is tuned to 12-1/2% (X^ or
higher (19% excess air or lower). Neither subcontractor saw this as
a particular problem. It was noted, however, that the design tem-
perature in Boston (OF) is higher than that in Albany (-10 F) and
that this would allow somewhat greater freedom in selecting host
homes in Boston.
• Subcontractor personnel as hosts
V Subcontractors are not constrained from considering their employees
as candidate host home owners. In fact, there are some distinct
advantages to selecting employee hosts, such as more ready access to
homes, better subcontractor control, and lower likelihood of
encountering problems with home owners.
• Schedule/decision
127
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Homeowner agreements
• Review work statement
• Complete prior to installation (i.e., by early August)
What homeowners will receive
• Remuneration
y Both subcontractors indicated that cost-free provision of (or reimburse-
ment for) the season's fuel should be the minimum reimbursement. An
alternative that might be offered to any host whose existing furnace
needs to be replaced is to install a new furnace when the test unit is
removed. (Average consumption per customer was estimated at about
1400 gal/yr. At $0.50/gal, this would cost about $700 and this figure is
reasonaly comparable with the installed cost of a new warm-air furnace.)
Also, for those whose old units are reinstalled, the subcontractors ex-
pect more than usual maintenance will be required during the following
heating season, and this service should be provided at no cost to the
homeowner.
• Information
J Rocketdyne should prepare a brief brochure for distribution to the host
homeowners. It should be no more than three or four pages long and
should include a summary of the program, a description of the furnace's
unique features, the color cutaway perspective illustration, and a state-
ment regarding what's expected of the home owner. (I.e., practice the
same type of home temperature control as last year, leave adjustments to
the subcontractor's service man, and don't meddle with special
instrumentation.)
128
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WHAT ROCKETDYNE WILL SUPPLY TO SUBCONTRACTORS
Information
• Drawings
• Furnace assembly, draft flap assembly, burner head, sealed air plenum,
cast-iron combustor, laminar flow element (warm-air flowmeter), con-
trol circuit diagram
\/ A complete set of available drawings was given to each of
the subcontractors at the meeting. Rocketdyne will prepare
sketches of two components not included in those drawings,
namely the sealed air plenum and the laminar flow element, and
will mail copies later.
\/ A copy of the control circuit diagram will be glued inside
each furnace.
Photographs
v/ A set of representative photographs was given to each
subcontractor.
Specifications
• Nominal operating conditions (Firing rate, C02 level, smoke No.,
furnace draft, warm-air flow and temperature rise, fan and limit
switch settings, etc.)
v/ Furnaces will not be preadjusted prior to shipment, so the
subcontractors will adjust them to meet the nominal specifi-
cations when they are installed. Rocketdyne will supply ex-
pected values with the test furnaces. The following were
discussed and should be viewed as tentative values:
- Firing Rate: 0.75 or 0.85 gph
- C02 Level: 12-1/2% or higher, consistent with smoke level
- Smoke: Less than No. 1 at steady-state
129
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- Furnace draft: Most Rocketdyne laboratory testing has been
with 0.03 to 0.05 in. 1^0 draft over the fire. Subcontrac-
ors normally adjust for about 0.01 in. 1^0 overfire draft;
mechanical draft-inducers would probably be needed to
approach the higher draft levels. It is anticipated that
the 0.01 level will be adequate, but Rocketdyne will test
this in the laboratory before finalizing a nominal value.
- Warm-air flowrate: Subcontractors will use normal industry-
accepted procedures to provide adequate warm-air flowrate
to the various outlets of the warm-air distribution system.
Resident comfort is the main criterion, rather than a
particular flowrate. The warm-air flowrate .usually is not
measured, but is estimated by summing calculated room
register flow requirements. Typically, total warm-air
volumetric flows range from 750 to 900 scfm for a 0.75-gph
furnace firing rate, and 85 F is a typical warm-air temper-
ature rise. In minimum air flow tests in the laboratory, a
test furnace with 80 F inlet air encountered 190 F limit
cutoff (i.e., 110 F rise) when the air flow was lower than
about 650 scfm. This indicates that limit cutoff normally
will not be encountered in most typical installations.
- Fan and limit switch settings: Normal practice is to set
the fan switch so that the fan comes on at about 100 F and
cuts off at about 85 F. Both of these controls will
probably need to be set approximately 5 to 10 F higher to
avoid cycling the fan at either end of the burner-on period
due to the massive heat sink effect of the cast-iron firebox
and, also, to aid in heat retention in that component. The
limit switch will be set at 200 F in the laboratory before
shipment of the units.
Hardware
• Three furnace assemblies
• Complete with burners, sealed air plenums, barometric control valves,
and flexible combustion air ducts
v/ New barometric control valves supplied by Lennox with the stock
furnaces will be used. The flexible combustion air ducts will
be 4-inch ID by 5 feet long.
v Two furnaces will be shipped to each subcontractor with two-stage
fuel pumps and one with a single-stage pump.
V An oil flowmeter will be installed in each test furnace before
it is shipped from Rocketdyne.
130
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\/ The fan and limit switch is positioned behind the cover plate
for the combustion air filter. This constitutes an inconvenience
for installing servicemen, and it was suggested that the switch
be moved or that the cover plate be redesigned to allow quick
removal. However, the existing cover plate is held in place by
only three easily-removed sheet-metal screws, so it is unlikely
that a more accessible design will be attempted in the short time
preceding installation.
V/ A question was asked as to whether the furnace design will be
changed in response to findings of the UL investigation and/or
EPA testing. Probably not. The UL results are now expected
to be learned too late to change anything short of a serious
safety problem. Most UL standards requirements have been tested
in the Rocketdyne laboratory; the only change being made as a
result is use of high-temperature wiring in a portion of the
control circuit. The EPA tests are intended to provide a point
of reference with respect to pollutant emissions.
• Key components (list attached)
• Spare parts (list attached)
SPARE PARTS TO EACH SUBCONTRACTOR
Components Number
Oil Burner
Optimum head 1
Spray nozzles, 0.75-70-A 6
0.85-70-A 6
Mircroswitch.es 4
Relays 3
Centrifugal clutches 2
Sealed-air system
Flexible duct 1
Plexiglas cover plates 2
Combustion air filters 12
(An extra fuel oil meter will be kept in the Hewlett-Packard automatic data
logger cabinet.)
131
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LIST OF ELECTRICAL AND FUEL-HANDLING COMPONENTS,
ROCKETDYNE/EPA INTEGRATED WARM-AIR OIL FURNACE
Component
Manufacturer
Manufacturer's part
or model number
Burner drive motor
Ignition transformer
"Franceformer"
Fuel pump
Spray nozzle
Centrifugal clutch
Miscellaneous burner
parts: ignition elec-
trodes, fuel line and
fittings, fuel tube
Blower drive motor
Primary control unit
Flame detector
Fan and overtemperature
limit switch
Draft flap microswitch
Relay (microswitch
bypass)
Socket (for relay)
Marathon Electric Co.
France Division,
Scott & Fetzer Co.
Westlake, OH
Sunstrand Hydraulics
Division of Sunstrand Corp.
Rockford, IL
Delavan Mfg. Co.
W. Des Moines, IA
Pioneer Products Co.
Elyria, OH
R. W. Beckett Co.
Cleveland, OH
Wagner Electric Corp.
St. Louis, MO
White-Rodgers Div.
Emerson Electric Co.
St. Louis, MO
White-Rodgers or
Honeywell
Honeywell, Inc
Bloomington, MN
Micro Switch,
Div. of Honeywell
Freeport, IL
American Zettler Inc.
Irvine, CA
Amphenol Connector Div.
Bunker Ramo Corp.
Broadview, IL
9PF48S34S45A
(115 vac, 2.3 amp
3450 rpm, 1/7 hp)
5 LAY 04
(10,000 V secondary)
A2VA-7016 (single
stageO' or B2VA-8216
(two stage) 3450 rpm
0.75-70-A
RT-3450
356-38485-05 (single-
phase induction, 115
vac, 7.6 amp, 1725 rpm,
1/2 hp)
668-453
956 (CdS Cell)
C554A
L4064A
311SM704-H2
AZ481-7-2
(115 vac, NC)
49SS8
(8-pin octal tube
socket)
132
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FURNACE INSTALLATION
Remove existing furnace
• Save all components for future reuse
• Store indoors
Insert test furnace
• Consider space requirements for
- Immediate connections
- Future instrumentation
• Connections
• Oil supply
- Pump compatibility
- Filter
• Warm-air outlet
y A warm-air plenum will extend above each furnace. There may or may
not be an A-shaped refrigerant evaporator coil inside the plenum, as
appropriate for the particular home. In every case, the inside of
the plenum will be insulated internally, typically with a 3/4-inch
thickness of high-density fiberglas composite,on five walls of a
rectangular plenum. The warm air will flow out of the plenum into two
or more distribution pipes which typically will not be insulated.
Evantually, Rocketdyne will add thermocouple instrumentation for
measuring the average outlet temperature. Usually, this will involve
an array of thermocouples. The approach that will be taken is to
study each furnace installation individually to determine how best to
instrument the outlet. In some cases, especially those with evapora-
tor coils, it may be possible to insert all .thermcouples into the
plenum. In other cases, it may be necessary to instrument individual
distribution pipes; if so, additional insulation will be added to the
outside of those pipes past the thermocouple insertion points.
133
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• Return air inlet
Temperature and flowrate measurements are integral with the 18 x 18 x
48-inch laminar flow element. A dummy section of .uninsulated duct
will be installed initially. Rocketdyne will build a filter into the
flow element inlet. Probably 18 x 20 inches or 18 x 24 inches, the
filter will be changed whenever the element is moved to another house.
• Flue
- Install new barometric control valve
- Barometric control'location
• Allow minimum clearance for measurement ports
v/18 inches of straight flue pipe upstream of sample point
v Either in vertical run or horizontal run
• Insulate flue pipe up to sealed air plenum (1-inch Fiberglas
with foil)
• Consider accessibility of sealed air plenum
- Cold air inlet from outside wall (nominal 7-inch dia-
meter)
/ Outdoor air supply will most likely be brought in
through the nearest basement window by replacing a
glass pane with a wood (or metal) plate. Outdoors,
provision will be made to draw air vertically up
into the intake pipe (i.e., a gooseneck) at a level
such as to avoid ingesting rain or snow or covering
the inlet with snow. A screen (1/4-inch mesh or
coarser) should also be placed over the inlet to keep
birds and rodents out. The intake pipe should be
nominal 7-inch diameter. Inside the basement, it
should be insulated (e.g., with 1-inch Fiberglas) up
to the sealed air plenum. Alternatively, a self-
insulated flexible plastic duct section was recom-
mended by the subcontractors and would be suitable.
- Flexible duct outlet to combustion air filter inlet
(nominal 4-inch diameter)
134
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- Provision for furnace draft adjustment
V Generally, no special provision will be needed if the test
furnaces can operate OK with approximately 0.01-inch H20
draft. If higher draft is really needed, a draft inducer
may be required.
• Temperature control
V Replace thermostat if it is incompatible witn test furnace control
circuit.
135
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INITIATION OF TESTS
Subcontractor checkout
• Fire and tune burner
• Measure and adjust CO. level, smoke, and draft
V/ Bacharach Fyrite instrument is OK.
• Satisfactory appearance and stability of flame
• Warm-air circuit adjustments
• Flowrate versus temperature rise
V Air blower has adjustable belt drive
• Balance distribution
• Cyclical operation
• Limit switches
• Thermostat control
Rocketdyne checkout
• Survey performance versus stoichiometric ratio
• Steady-state and cyclical operation
• Emissions
V Emissions measurements via mobile van. Van hookup will
require access to two different 110 vac household circuits.
A flue gas sample will be drawn to the van through a length
(up to 100 feet) of 1/4-inch OD Teflon tubing. An ice bath
near the furnace will be used to condense moisture from the
gas sample before it is taken outdoors. Thermostat
control of the furnace will be overridden by a cycle-
controller so that data are taken during consistent cycle
timing conditions for all furnaces.
136
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• Efficiency
/ Rocketdyne will install a 110 vac receptacle from the furnace
vestibule for powering the cycle-controller, data-loggers, etc.
Provisions will be made to bolt the event-timer data logger
securely to each furnace, via field fitting. Similarly, the
larger Hewlett-Packard automatic data logger will be amenable
to field attachment to the furnace cabinets.
Fuel variation
• Household fuel
I/Take an initial sample of fuel being burned and measure furnace
behavior with it.
• Rocketdyne laboratory fuel
V/Burn a small quantity (about 1 gallon) of reference fuel and
measure initial emissions. Provides comparative data from all
six furnaces.
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PERIODIC CHECKS
Nominal monthly periods
• Joint visit
V Subcontractor serviceman will probably stay for entire duration of
Rocketdyne visit.
• Subcontractor check (no readjustments)
• Burner condition - CO., smoke, draft
• General furnace operation
• Filters
v Both the hammock-type warm-air filter and the small combustion
air filter will be examined monthly, but they will be replaced
only when needed.
• Rocketdyne check
• Operation of data logging instrumentation
v Replace used tape recorder cassette with a fresh one.
• Furnace performance, standardized cycle-averaged
• Emissions
/May require overnight parking of and ^-150 W power for
instrumentation van at host sites for warmup.
• Efficiency
• Determine whether any adjustment is required
• If so, repeat measurements
• Change instrumentation as required
• Hewlett-Packard data logger
• Fuel samples
v All sites to start season with a full tank.
/During the next periodic call after a fuel delivery has been made,
a 1-pint sample will be taken of the fuel then being burned. (This
procedure deviates from that stated in the Statement of Work.)
138
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MOBILE LABORATORY
Vehicle
• 1-Ton Ford Econoline 250 (1976)
• 130-inch wheel base
• 4850-pound net, 2800-pound maximum payload
• Sliding door on right side
• Two shock-mounted racks of instrumentation
• Equipment needed for field testing
• Alarm system
• Locks on all tool cabinets
• Winterization
v Snow tires (buy them in the East)
V/Studded tires are now illegal in New York; investigate
chemical radials (Goodyear, Michelin, or Continental)
y Chains (may never use, but carry anyway)
V Insulation (perhaps 1" thick rigid Styrofoam sheets)
/Anti-freeze (60% ethylene glycol/40% water solution)
• 110 vac space heater
• 12 vdc to 110 v, 60 cycle a-c power inverter
v Needed to supply power to two NDIR and one chemiluminescent
analyzers to keep them warmed up during highway transit
(approximately 250 watts)
Storage between monthly visits
V Both subcontractors have secured storage areas which can be used.
Indoors, preferably. Unheated garage OK. May want subcontractor to
move van into heated garage the day before Rocketdyne engineer begins
monthly checks.
139
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EMERGENCY SERVICE
Subcontractor available 24 hours/day
• Principal concern:
V/To ensure that each host home's heating system is functioning
properly and safely.
V Keep the customers/hosts happy.
• Authorized to exercise judgment
• Adjust, repair, or replace a malfunctioning test furnace, as
required, to restore interrupted service in a timely manner.
V Subcontractors stated that lawsuits over disruption of service
and/or damages are rare. Selection of host customers is a key
element of avoiding problems.
V Replacement parts and/or labor costs beyond those included in
the statement of work would be bases for subcontract changes.
Contact Rocketdyne buyer: Ms. Angle Cicchese (213) 884-3200.
Mail all invoices to her with copies to R. Bartley and
P. Combs.
• Promptly inform Rocketdyne engineer by telephone of action taken
V Subcontractors will be given a list of Rocketdyne business and
home phone numbers.
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MISCELLANEOUS TOPICS
Subcontractor recordkeeping and data submittal
• Review statement of work
Handling delays
v/ Simply reschedule visits affected, not a big problem.
Week-end work
\/Should not normally be planned. May be worked in if necessitated
by unusual circumstances.
V Subcontractors will probably try to have same serviceman do all
periodic testing.
Mid-test period progress review
\/ Rocketdyne will probably schedule a 1-day meeting at one of the
test locales sometime in early 1978.
141
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STATEMENT OF WORK FOR
OIL FURNACE SERVICE CONTRACTOR
Seller shall provide support services, in accordance with Rocketdyne specifi-
cations provided herein, for field testing three (3) prototype integrated
warm-air oil furnaces in residences in his local business area. Five dif-
ferent categories of services will be provided by Seller, namely: (1) selec-
tion of host residences, (2) installation of test furnaces, (3) periodic
service calls, (4) removal of test furnaces upon completion of testing, and
(5) record-keeping. Details of these categories are given in subsections of
this flysheet.
The test furnaces are described in accompanying Flysheet B.* All three fur-
naces will be identical. Background information concerning their development
is given in the enclosed copy of ASME paper 76-WA/Fu-10.*
Buyer will perform related and concurrent measurements, flue gas sampling and
analysis on each test furnace. The extent of interaction and cooperation
which will be required between the Seller and Buyer personnel is specified in
this flysheet.
SELECTION OF HOST DWELLINGS
Based upon the Seller's records and knowledge of his clients who have oil
furnaces, he shall identify at least five candidate homeowners whose homes,
heating systems, family habits and interests would, in his opinion, support
their selection as hosts for a test furnace. Among the candidate host houses,
it is desirable to maximize variety, for example, in type of construction
(frame versus brick), style of residence (single-level versus two-story),
type of residence (single-family versus duplex or townhouse), exposure (hill-
top versus valley, or open versus wooded, terrain) and orientation (north
versus southfacing). The installation and test procedures will probably
require somewhat more than normal free space around each test furnace, so it
is anticipated that basement installations will be preferred; almost
certainly, closet installations should be avoided. The families' lifestyles
must be amenable to providing access to the furnace during periodic (nominally
monthly) service and monitoring calls, and to a certain amount of disruption
and inconvenience that this entails.
The Seller shall establish willingness of the identified candidate homeowners
to participate as hosts in the field test investigation, but without making
definite commitments. At this point, the cognizant Rocketdyne engineer will
*Information not reproduced in this Appendix.
142
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visit the contractor's office to review the list of candidates; together, he
and the Seller will select three preferred hosts and rank the others in a
list of alternates. Thereafter, the Seller will establish formal agreements
with three host homeowners. It is anticipated that each agreement will
provide for:
1. Assurance of periodic access to the dwelling's heating system by
Seller and Buyer personnel. (Seller's personnel should always
accompany Buyer's personnel visiting the host residences. Maximum
coordination should be exercised so as to minimize the total number
of visits.)
2. Each homeowner to hold Buyer (Rockwell International) harmless for
injury to or death of any person(s) and for loss of or damage to
any and all property arising out of the acts or omissions of the
homeowner.
3. Appropriate homeowner remuneration to make attractive their accept-
ance of inconveniences during preparation and restoration of the
heating system and during the heating season and for the requested
waiver of liability.
INSTALLATION OF TEST FURNACES
The Seller shall be responsible for installing the test furnaces in conform-
ance to applicable building codes and safety standards. Buyer will provide
assistance in this regard as needed and to the extent possible, e.g., in
requesting assignment of a state approval number, in explaining system modifi-
cations to a county or township fire marshall, etc.
Prior to delivery of test furnaces by Buyer and based on drawings and other
pertinent information supplied by Buyer, the Seller shall ensure that all
materials and equipment needed for prompt installation and activation are
readied for each host residence. These preparations will include ensuring
that the fuel oil tank is filled and providing Buyer with a 1-pint sample of
the tank's contents. It is anticipated that the host agreement will provide
for oil deliveries by the host's existing fuel oil supplier. In the event
that the oil tank is refilled during the test period, Seller will take an
additional 1-pint sample during the next regular service call after each
refueling. Each sample will be adequately labeled to identify the date
sampled and the source residence; Seller may simply hold the sample(s) until
the next regular visit of the Rocketdyne engineer.
Upon receipt of test furnaces from Buyer, Seller will install a unit in each
of the host residences. It is anticipated that the existing furnaces will be
removed from the host heating systems and replaced with the test units. Seller
will be responsible for storing the existing units during the field test
period so that they may be reinstalled later. Installation of test furnaces
will include, but not necessarily be limited to, fabrication of adapter sec-
tions of duct, provision of an outdoor air supply for the sealed air system
(4-inch-diameter galvanized duct insulated with a minimum of 1-inch-thick
143
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foil-covered Fiberglas) and connection of all required plumbing and electrical
circuits according to applicable local codes. Provisions will also be made
for future insertion of a metering section in the return air duct leading into
the furnace and for a number of 1/2-inch-diameter holes in the flue pipe for
instrument insertion and sample extraction. The metering section (supplied by
Buyer) will be a straight 48-inch-long section of 18-inch-square duct made of
galvanized sheet metal. Buyer will provide appropriate drawings well ahead
of the actual installation.
Checkout and startup of the unit will conform to normal heating industry prac-
tices, including measurement of flue gas temperature, C02 content and smoke,
adjustment of burner excess air level, firebox draft, and distribution of
warm-air to the residence. At the same time or soon thereafter, Seller will
accompany the Rocketdyne engineer and assist with installation of two per-
manent recording instruments (a fuel meter and a recording clock) and will
stand by while Buyer obtains more complete emissions measurements. It is
anticipated that this procedure will require one full day for each residence
after the completion of the mechanical installation, per se, and that all
three units will be in normal service prior to 1 October 1977.
PERIODIC SERVICE CALLS
Throughout the 1977-1978 heating season, from initial installation to, say,
mid-June 1978, it is intended to let the test furnaces operate normally and
without adjustment, if possible. During that time, Seller will be available
for 24-hour emergency service requirements and will inspect the furnace at
least once a month. A Rocketdyne engineer will make emissions and performance
measurements on a monthly schedule, and it is expected that Seller will
accompany him, at least for the first part of his visit, to each residence,
and perform the monthly inspection before emissions are measured. Furnace
operation should not be adjusted unless an unsafe or excessively smoky con-
dition exists. If an adjustment is found to be necessary, both the Seller and
Buyer should make and record their measurements both before and after furnace
operation is adjusted. These monthly inspection calls will probably take an
average of 1 to 1-1/2 man-days per month for all three furnaces; they will
normally be scheduled a month in advance by coordination among the Seller, the
homeowners, and the Rocketdyne engineer.
An auxiliary package of instrumentation will be used to measure data so that
thermal efficiency can be correlated to furnace cycle timing and burner firing
duration. The package will be installed on one furnace and left long enough
to gather sufficient data (nominally, one month), then moved to another fur-
nace. Buyer personnel will be wholly responsible for all functions concerned
with the instrument package and the resultant data, but will need assistance
from Seller in installing and removing it. Installation will be timed to
coincide with the regular monthly inspections as will removal a month later.
It is anticipated that the service call might be lengthened by approximately
one-half day to remove the package from a furnace and by approximately three-
fourths of a day to install it on another furnace. Installation, removal, or
both, of this package will be involved in four of the eight monthly inspection
periods.
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REMOVAL OF TEST FURNACES
Upon completion of the field testing, Seller shall remove the test furnaces
from all three host residences. The test units will be recrated, banded and
shipped to Rocketdyne in Canoga Park, California, using original shipping
crates. Rocketdyne will bear shipping costs, FOB point of origin.
RECORDKEEPING/REPORTS
Seller shall obtain and supply to Buyer data covering each host residence's
history of oil consumption and service requirements for the preceding two
years (unless, of course, the home is not that old).
Seller also will maintain records of test furnace operating conditions
observed during each inspection call, any service or adjustment required, oil
consumption, degree day history for the test area throughout the test period,
any unusual climatic conditions which might impact interpretation of test
data obtained, and any variations in the number of people living in each host
site. These data will be delivered to Buyer within 30 days after completion
of the test period.
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APPENDIX G
INFORMATION FOR HOMEOWNERS
You and your home have been selected to take part in a unique and meaningful
field test study of a residential oil furnace that emits fewer air pollutants
and operates more efficiently than conventional oil furnaces. Within a few
weeks, your present furnace will be replaced temporarily with the new test
furnace. Your home will be heated by this new unit during the 1977-1978
winter heating season. Identical test furnaces will be installed in five
other homes in the vicinities of Boston, Massachusetts and Albany, New York.
BACKGROUND
In its continuing pursuit of ways to improve air quality in the United States,
the Environmental Protection Agency has sponsored a number of research and
development programs designed to promote the development of equipment pro-
ducing lower levels of noxious emissions. Home heating equipment contributes
substantially to lower air quality, especially in urban areas that experience
relatively severe winters. Accordingly, EPA has supported R&D work on resi-
dential furnaces. Rocketdyne has contributed to this effort by performing
studies of residential oil burners and oil furnaces under contract to the EPA.
The installation of a test furnace in your home is part of the last phase of
those Rocketdyne studies. Until now, the investigations have been confined
to laboratory investigation of oil burner and burnace design changes that
could lower pollutant emissions and, simultaneously, reduce fuel consumption.
Several design criteria were established as being generally applicable to both
residential warm-air furnaces and hydronic boilers. These criteria were used
to modify an existing commercially available, warm air oil furnace for proof-
of-concept evaluation in the Rocketdyne laboratory. Laboratory results in-
dicated that, by comparison with the estimated average performance of com-
parable existing furnaces installed in homes, the emission of oxides of
nitrogen (NOx) into the atmosphere could be reduced by 65% or more, and
cyclical or seasonal efficiency could be increased"by 10 percentage points or
more without increasing the already low emissions of products of incomplete
burning (namely, carbon monoxide, unburned hydrocarbons, and smoke).
PURPOSE OF THE FIELD TESTS
Field testing is a logical continuation from those encouraging laboratory
results. Our objectives are to demonstrate that the underlying low emission
design criteria can be applied practicably to residential space heating
equipment and that they are compatible with increased fuel efficiency.
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A further objective is to test for a long-enough time period to document the
stability of furnace operation, emissions and efficiency, and to observe
relative maintenance requirements. The basic purpose, of course, is to
provide strong encouragement for furnace manufacturers to adapt the low
pollution design criteria to their own products.
UNIQUE FEATURES OF THE INTEGRATED FURNACE
The new furnace being installed in your home, like the laboratory prototype
after which it is patterned, was built by making several modifications to a
commercially purchased, brand-name furnace. Many components, including the
outside cabinet, have been altered only slightly, if at all. Components
which have been modified or replaced are concerned primarily with the fuel
combustion functions of the furnace and these are predominantly inside the
cabinet. The^major changes are illustrated in the accompanying color cut
away sketch of an integrated furnace. Outwardly, therefore, the new unit may
not look much different than your present furnace.
The optimum oil burner is a specially "developed unit designed to operate with
very little excess combustion air and to produce less NOX than conventional
burners. The combustor is made of cast iron and does not have an insulating
refractory lining. It is partially cooled by the warm air circulating over
cooling fins on its outside surface and this leads to further reduction of
NOx emissions. The size and degree of cooling of the combustor are matched
to the burner to form an optimum combination.
Air required by the furnace is brought in from outdoors through the furnace's
sealed air system. It enters a distributor box built around the draft con-
trol damper on the flue pipe. Part of the air is drawn through the damper and
mixed with the flue gases, while the rest is ducted into the burner compart-
ment. There it is filtered before being drawn into the burner and used for
combustion air. This use of outdoor air to fulfill the furnace's needs will
lower your home's demand for heat and humidification, and filtering it will
allow the burner to be tuned more precisely to optimum firing conditions.
The combustion air inlet to the burner is fitted with a draft control assembly
that closes a damper when the burner is not firing. This helps reduce heat
losses up the flue during standby periods.
MONITORING FURNACE PERFORMANCE
An ideal situation would be for the test furnace, once it is installed and
running in your home, to operate for the entire heating season without
requiring either adjustment or serviceman maintenance. Its performance will
be monitored to see how closely this ideal is approached. Normal maintenance
functions, such as changing dirty filters, will be performed by service
personnel who have been instructed not to retune the burner or adjust furnace
operation unless an unacceptable condition is encountered.
Furnace performance will be monitored by a service representative, from the
local company which will install the test unit, and a Rockefcdyne engineer who
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will visit your home once a month to observe its operation and take measure-
ments. Occasionally, they may be accompanied by other engineers or managers
associated with the field test study. Some instruments will be installed
permanently on the furnace, and others will be brought in for more or less
temporary use. The permanent instruments will record data primarily concerned
with fuel utilization efficiency. An assembly of several instruments for
analyzing the furnace combustion products will be brought to your home each
month. That assembly is installed in a van which will be parked outside your
home. A long, small-diameter plastic tube will be connected between the
furnace's flue and the van to draw a continuous sample of flud gases to the
instrumented van. This approach avoids, as much as possible, disruptions of
your normal household activities.
WHAT YOU CAN DO TO HELP
You have already make a big contribution to the field verification study by •
agreeing to participate in it. The EPA, Rocketdyne and the entire field test
team are most appreciative of your willing cooperation. We are concerned,
first and foremost, with your comfort and safety throughout the test period
and we want you to be satisfied with having our test furnace in your home.
It it performs as well as it has in our laboratory, you should be able to
appreciate its presence without having to give it any attention at all. In
that case, your most important contribution will be to continue using your
heating system in the same way you did last winter. The test furnace's oil
consumption will be compared with your usage in previous years and, although
temperature records can be used to account for differences in winter severity,
we have no way of correcting for biases in the data caused by altered heating
habits. Oil price increases and shortages and emphasis on conservation have
contributed to changing habits over the last few years, so the most valid
comparison probably will be between the 1976-77 and the 1977-78 heating
seasons. Therefore, we ask that you maintain the same thermostat control
practices (including morning warmup, daytime and evening settings and night
setback) that you used last year.
If you find that the way your home is heated has changed sufficiently from
last year that some adjustment seems to be needed, please discuss it with
your service representative.
With the exception of setting the thermostat control, all adjustable controls
on the furnace and the heating system should be left as they are set by
your service representative. If something about the heating system, including
the instrumentation, appears to be in need of service, you should call him,
rather than trying to correct or adjust it yourself. If you're interested
in knowing what things are for and how they work, we will be pleased to
dscuss and demonstrate them while we're in your home. Hopefully, having
freed you from responsibility for routine maintenance will add to your enjoy-
ment of participating in the study.
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
REPORT NO.
EPA-600/7-79-037a
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Design Optimization and Field Verification of an
Integrated Residential Furnace—Phase 1
6. REPORT DATE
February 1979
6. PERFORMING ORGANIZATION CODE
. AUTHOR(S)
A.S. Okuda and L.P. Combs
B. PERFORMING ORGANIZATION REPORT NO.
9 PERFORMING ORGANIZATION NAME AND ADDRESS
Rockwell International
Rocketdyne Division
6633 Canoga Avenue
Canoga Park. California 91304
10. PROGRAM ELEMENT NO.
EHE624A
11. CONTRACT/GRANT NO.
68-02-2174
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AMD PERIOD COVERED
Phase; 8/76-12/78
14. SPONSORING AGENCY CODE
EPA/600/13
is. SUPPLEMENTARY NOTES JERL-RTP project officer is G. Blair Martin, MD-65. 919/541-
2235.
. ABSTRACT
repor{. describes Phase 1 of a two-phase investigation to: (1) further
optimize the design of a prototype low-emission residential furnace that was derived
from earlier EPA-funded studies; and (2) obtain field verification of its emission
and performance characteristics. It gives details of: (1) analytical and experimental
studies to optimize the furnace design and its nominal operating ranges , and to
ensure conformance with appropriate safety standards; (2) planning all aspects of
the Phase 2 field test investigation, including selection of test locales and host
homes, provision of local installation and service support, and all logistic and
scheduling considerations; and (3) studies of the integrated furnace's capabilities to
function properly with such alternate fuels as natural gas and methanol. The proto-
type furnace, with a cast iron firebox, met all emission goals (i. e. , NOx < 0. 65 g/
kg, CO < 1.0 gAg, UHC < 0. 1 gAg, and a Bacharach smoke number < 1) at low
excess air (20%). Based on climatic characteristics and available support services ,
Albany and Boston were selected for field verification of furnace performance.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Pollution
Furnaces
Residential Buildings
Design
Tests
Pollution Control
Stationary Sources
Residential Furnaces
13B
13A
13M
14B
18 DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (ThuReport)
Unclassified
21. NO. Or PAGES
161
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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