United States Office of Policy Planning & Evaluation EPA 231-R-98-014
Environmental Protection (2126) July 1998
Agency
oEPA
Climate Wise
Wise Rules for
Industrial Efficiency
A TOOL KIT FOR
ESTIMATING
ENERGY SAVINGS
AND GREENHOUSE
GAS EMISSIONS
REDUCTIONS
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Wise Rules for
Industrial Efficiency
A Tool Kit for Estimating Energy Savings and
Greenhouse Gas Emissions Reductions
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For more information on the Climate Wise Program, call the Wise Line at 1-800-459-WISE.
Climate Wise would like to thank the following people for their assistance and input:
Michael R. Muller, Director, Office of Industrial Productivity & Energy Assessment, Rutgers University.
Steven C. Schultz, Energy Engineering Specialist, 3M Company.
Kenneth F. Kraly Director of Engineering, Cosmair, Inc.
Harry A. Kauffman, Director Energy and Fire Policy Management, Johnson & Johnson.
Lee Link and Rob Penney, Energy Ideas Clearinghouse, Washington State Energy Office.
George M. Wheeler, Director, Industrial Assessment Center, Oregon State University.
This document was developed for the U.S. Environmental Protection Agency under contract number EPA 68-W6-0029.
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1. Introduction 1
The ClimateWise Program 1
Overview 1
Information Sources 1
Using the Toolkit 3
2. Boilers 5
Introduction 5
Boiler Load Management 6
Tune-Up and Air/Fuel Ratio Optimization 6
Burner Repalcement 7
Stack Heat Losses and Waste Heat Recovery 7
Slowdown Control and Waste Heat Recovery 7
Summary of Wise Rules for Boiler Systems 8
3. Steam Systems 10
Introduction 10
Maintenance of Steam Traps 10
Reducing Leaks 11
Reducing Heat Losses 11
Vapor Recompression 11
Condensate 11
Summary of Wise Rules for Steam Systems 12
4. Process Heating 14
Introduction 14
Insulation and Heat Containment 14
Combustion Air Control 15
Process Waste Heat Recovery 15
Specific Process Heat Applications 15
Direct Heating 16
Summary of Wise Rules for Process Heating 16
5. Waste Heat Recovery and degeneration 18
Introduction 18
Waste Heat Recovery 18
Cogeneration 19
Summary of Wise Rules for Heat Recovery and Cogeneration 20
Table of Contents Wise Rules
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6. Compressed Air Systems..................................................^
Introduction 22
Use Cooler Intake Air 23
Match Compressor with Load Requirement....... ............23
Reduce Compressor Air Pressure ..........23
Reduce or Eliminate Compressed Air Use 24
Eliminate Air Leaks 24
Recover Waste Heat 24
Filters and Coolers 25
Summary of Wise Rules for Compressed Air Systems ............25
7. Cooll.........................................^
Introduction .........27
Energy Efficient Chillers and Refrigeration Units 27
Cooling Tower Water 28
Refrigeration and Chillers 28
Freezing 28
Variable Speed Drives 29
Summary of Wise Rules for Process Cooling Systems ............29
Appendix A: Sector-Specific Energy Savings Potential................
Appendix B: Conversion Factors and Emission Coefficients[[[52
Appendix C: Summary of Wise Rute.........................................
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The Climate Wise Program
Climate Wise is a partnership initiative sponsored by the U.S.
EPA, with technical support from the U.S. DOE, designed to
stimulate the voluntary reduction of greenhouse gas emissions
among participating manufacturing companies. Climate Wise
hopes to spur innovation by encouraging broad goals, providing
technical assistance, and allowing organizations to identify the
most cost-effective ways to reduce greenhouse gas emissions.
Climate Wise currently has more than 400 partners, representing
about 12 percent of U.S. industrial energy use. As part of their
Climate Wise commitment, partner companies across the country
develop comprehensive Action Plans that describe their energy
efficiency and pollution prevention goals, the specific actions
undertaken to achieve these goals, the time frame for implement-
ing commitments, and estimates of the impacts on energy, costs,
and emissions from these actions. To date, Climate Wise Partner
companies have submitted Action Plans detailing more than 1,000
individual actions to reduce greenhouse gas emissions and prevent
pollution. About half of these actions pertain to energy efficiency
measures in industrial operations such as: boiler and steam sys-
tems, compressed air systems, energy management operations,
motor systems, process heating, and process improvements.
Partner companies also pursue non-process energy efficiency mea-
sures such as lighting, HVAC, and building shell improvements,
as well as water conservation, recycling, pollution prevention and
educational outreach.
Overview
The Wise Rules for Industrial Efficiency - "Wise Rules Tool Kit" -
was developed to help partners make the most of their Climate
Wise participation and generate interest and commitment in
support of energy efficiency and pollution prevention efforts. It
provides Climate Wise Partners with simple rules for estimating
energy savings and greenhouse gas emissions reductions from a
wide range of industrial energy efficiency measures, based on a
large number of resources. Information on typical cost savings and
paybacks are also provided. The Wise Rules focus on six process
energy end-uses including boilers, steam systems, process heating,
waste heat recovery and cogeneration, compressed air systems, and
process cooling. Six chapters describe energy efficiency measures
and provide Wise Rules on typical energy and cost savings for each
of these major process end-uses. This information can help your
company identify and evaluate alternative energy efficiency activi-
ties. It can also help you to develop your Climate Wise Action Plan
— your statement of commitment under your Climate Wise
Participation Agreement.
Climate Wise will update this document periodically as we gather
new information on industrial energy efficiency measures. We wel-
come your feedback and input on the Wise Rules Tool Kit, includ-
ing other rules that you have found useful and would like to share,
or requests for new Wise Rules for specific end-uses. Please phone
in your comments to the Wise Line at 1-800-459-WISE, fax them
to 703-934-3968, send them via electronic mail to:
WiseLine@ICFKaiser.com, or mail them to:
Climate Wise
c/o ICE Kaiser Consulting Group
9300 Lee Highway
Fairfax, Virginia 22031
Information Sources
The Wise Rules Tool Kit is a compilation of some of the best infor-
mation available on industrial energy efficiency. These rules are
based on energy efficiency research and engineering principles, the
experience of Climate Wise Partners, and government sources
such as the U.S. Department of Energy's Industrial Assessment
Center (DOE/IAC) energy audit database. These resources pro-
vide a wealth of energy efficiency and other information in the
manufacturing sector, including energy, cost, and operating data.
The Wise Rules capture broad categories of efficiency improve-
ments such as "air compressor efficiency measures" and more
detailed actions such as "optimize boiler air-to-fuel ratio." The
Wise Rules also provide multiple perspectives on efficiency oppor-
tunities by expressing energy savings as a percent of a particular
end-use's energy consumption (e.g., optimizing air-to-fuel ratio
1. Introduction
Wise Rules
Pagel
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can reduce boiler fuel use by two to 20 percent), as a percent of a
facility's total energy use (e.g., steam trap maintenance can reduce
a facility's total energy use by 3.4 percent), or per unit change in a
physical parameter (e.g., for every one psi decrease in air compres-
sor pressure, energy use is reduced by 0.7 percent). To make them
as useful as possible, the Wise Rules are presented in a variety of
formats, including graphs, bullets, and tables. In addition, we have
provided a handy reference guide to identify energy efficiency
opportunities for specific manufacturing sectors (see Appendix A).
The DOE/IAC energy audit database was an important source of
information for the Tool Kit. The database contains information
from industrial energy assessments conducted at small-to-medium
sized manufacturing facilities by teams of faculty and students
from accredited engineering schools in 30 universities across the
country. The Wise Rules Tool Kit includes information on the
expected impacts from approximately 27,000 specific improve-
ments and upgrades from 4,300 detailed facility audits conducted
between 1990 and 1997. The majority of the auditors' recom-
mendations had relatively short (1 to 2 year) payback periods and
were expected to be implemented within two years of the audit.
The impacts from broad categories of efficiency recommendations
in the DOE/IAC audits are summarized in Introduction Table 1.
For example, boiler efficiency measures were recommended dur-
ing 20 percent of the 4,300 audits and were expected to save on
average 2.8 percent of a. facility's total energy use, or an average of
2,600 MMBtu per year. The average cost of implementing boiler
efficiency measures was expected to be $5,300 with average first-
year savings of $7,200 for an expected average simple payback of
nine months. Compressed air efficiency measures were recom-
mended during 68 percent of the audits. The average savings from
Introduction Table 1: Summary of Efficiency Measures from the DOE/IAC Database"
End Use
Recommendation Average
Boilers
Rate
(% of audited facilities)
20%
Annual
Average
Annual
Energy Savings Energy Savings
(% of total facility (MMBtu)
energy use)
Average Average
Implementation Cost
Cost Savings
2.S
2,600
$ 5,300
$ 7,200
Average
Simple
Payback
(months)
Steam Systems 13%
2.0%
2,400
3,300
$ 7,100
Furnaces & Ovens 4%
2.S
2,500
$ 5,500
$ 8,100
Process Heating
1%
2.2%
3,600
$ 7,500
$ 12,200
Heat Containment 22%
1.5%
1,100
$ 1,100
$ 5,100
Heat Recovery
26%
i.6%
3,700
$ 16,500
$ 12,500
16
degeneration*
3%
9.1%
31,000
$667,500
$233,600
34
Air Compressors 68%
0.4%
300
1,600
4,300
Process Cooling
6%
1.1%
1,000
18,900
$ 11,200
20
* Based on DOE/IAC estimates at audits of 4,300 manufacturing companies (1/90-7/97). Savings may not be additive.
**Cogeneration energy savings are based on primary fuel savings from electricity generation, including fuel inputs at off-site powerplants for purchased electricty.
Definition of Terms: The recommendation rate is equal to the number of facilities receiving a particular recommendation (e.g., repair steam leaks) divided by the total number
of facilities audited (=4,300). Average percent energy savings are defined as the average reduction in z facility's total energy use from a specific recommendation. Average annual
energy and cost savings reflect first year savings. Cost savings are primarily based on energy cost savings, but also may include other cost savings. The average simple payback is
the average implementation cost divided by average annual cost savings, times 12 (months per year).
Page 2
Wise Rules
1. Introduction
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air compressor efficiency measures were 0.4 percent of total facility
energy use, or an average 300 MMBtu annual reduction in each
facility's energy use. The average cost of implementing compressed
air efficiency measures was expected to be $1,600 with average
first-year cost savings of $4,300 for an average simple payback of
five months. Similar rules developed for a range of other broad
actions as well as more detailed measures are presented in the body
of the Wise Rules Tool Kit. The estimated audit impacts for spe-
cific industry sectors are presented in Appendix A.
Using the Tool Kit
The Wise Rules were developed to help you take full advantage of
your participation in the Climate Wise Program. As you begin to
develop your Climate Wise Action Plan, the Wise Rules can help
you and your Climate Wise team generate ideas for energy savings
opportunities in your facilities. The Tool Kit provides a quick scan
of measures along a number of dimensions, including potential
energy savings, implementation costs, energy costs savings, and pay-
back. Use the Wise Rules, along with information on the processes
in your operations, to screen a broad range of efficiency measures
and to eliminate less attractive options based on your company's key
criteria. The Tool Kit provides background information on all of the
Wise Rules so that Climate Wise Partners will have a better under-
standing of how and when to use them. We have also provided
references to the primary data source for every Wise Rule so that
partners can learn more if they desire. Appendix D of the Tool Kit
contains a summary of key references and resources.
Once measures have been identified, you can use the Wise Rules to
estimate project-level energy savings and C02 emissions reductions
to be reported on your Climate Wise Action Plan. While you will
want to refine these estimates over time and track actual results for
completed projects, the Wise Rules can serve as place-holders until
your experience provides you with better, site-specific data. You
may also find that you want to develop your own rules based on
your engineering analyses and metered data. In this way you can
tailor Wise Rules for processes specific to your company or based
on your company's operations, energy prices, and other factors.
The Tool Kit also provides information required to calculate C02
emissions reductions, as required in your Climate Wise Action
Plan. C02 emission factors provided in Appendix B of the Tool Kit
can be used with the energy savings estimates based on the Wise
Rules to estimate total emissions reductions from your actions.
It is important to keep in mind a number of points when using
the Wise Rules:
• The Tool Kit provides savings estimates for many impor-
tant efficiency measures, but it is not a exhaustive list of
industrial efficiency opportunities. A number of process-
es and end-uses are not included here that may offer sav-
ings to your company (e.g., lighting and motors). There
may also be attractive measures — including pollution
prevention measures — applicable to your specific
processes and operations that your company should con-
sider. Moreover, many of the Wise Rules reflect efficien-
cy recommendations with relatively short (1 to 2 year)
payback periods. Your company's payback requirement
may be longer for some types of projects. When identify-
ing energy efficiency and pollution prevention opportu-
nities, it is important not to limit your actions to those
measures included here.
• The Wise Rules can provide simple savings estimates but
they cannot take the place of detailed engineering analy-
ses based on site-specific data and operating parameters.
The Wise Rules are based on typical experience and gen-
eral engineering observations from a number of sources.
The energy audit data reflect the energy and cost savings
estimates (not actual experience) across many industry
groups, over several years and across many parts of the
country. Be sure to consider your company's unique cir-
cumstances when applying Wise Rules. For many pro-
jects, more detailed analysis will be desirable.
• Some Wise Rules may be only applicable under specific
operating conditions (e.g., only to equipment of a certain
size or within a specific temperature range). Some effi-
ciency measures for the same or related end-uses may
interact, such that the total energy savings from complet-
ing two measures may be less (or more) than the sum
of the two measures' individual impacts. Because Wise
Rules are drawn from a variety of sources, savings esti-
mates may not be comparable, even when the energy effi-
ciency measures are similar. For example, some Wise
Rules express savings for an energy efficiency measure on
the basis of specific equipment energy consumption,
while others are expressed as a percent of a facility's total
energy savings. Such rules may not be comparable,
1. Introduction
Wise Rules
Pages
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because they may assume different specific measures,
implementation levels, or contributions of the end use to
total facility energy-use.
All Wise Rules are expressed as "energy savings" to allow
easy comparison across measures. However, many of the
key references and resources are based on efficiency
impacts — a closely related measure.
A comprehensive analysis of efficiency opportunities
should also examine secondary impacts of savings mea-
sures. These include impacts on operations, maintenance,
productivity, and the environment. For example, changes
in boiler operating parameters may have secondary effects
on emissions of nitrogen oxides, particulates, or carbon
monoxide. These may all be important decision criteria
for your company.
Energy savings estimates based on the Wise Rules cannot
take the place of measuring the results of implemented
projects. For some projects, you may want to implement
energy tracking and/or metering systems to evaluate the
success of your Climate Wise efforts and the return on
your investments. This information can later be used to
develop Wise Rules for your company.
Page 4
Wise Rules
1. Introduction
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Introduction
Boilers are one of the most important energy uses in manufac-
turing, typically comprising more than a third of total manu-
facturing energy demand. A boiler generates hot water or steam,
typically from the combustion of coal, oil, or natural gas. A net-
work of pipes delivers steam (or hot water) to provide heat for a
variety of process and heating applications. Once the heat has been
extracted from the water or steam, another network of pipes
returns the condensed water back to the boiler where it is cyclical-
ly reheated. There are several different types of boilers including
natural draft, forced draft, hot water or steam, and fire tube or
water tube. The typical boiler used in small-to-medium sized
industrial operations is a forced draft steam boiler at 120-150 psi
and approximately 150 hp (equivalent to 5 MMBtu/hr). Large
Boiler Figure 1
Energy Savings from Boiler Efficiency Measures*
industrial boilers can exceed 7,500 hp (250 MMBtu/hr). Typical
boiler efficiencies range from about 70 to 85 percent depending
on fuel type, configuration, and heat recovery capability.
Several boiler efficiency measures may be of interest to Climate
Wise Partners: boiler load management, burner replacement,
upgraded instrumentation, tune-up and air/fuel ratio optimiza-
tion, stack heat loss prevention, waste heat recovery, and blowdown
control. Boiler Figure 1 illustrates the potential energy savings
from boiler efficiency measures based on IAC audit recommenda-
tions. Boiler efficiency measures with an average savings of about
three percent of facility energy use, and a simple payback of nine
months were recommended at 20 percent of the 4,300 facilities
audited. Boiler load management measures have a relatively high
Recommendation Rate
0% 2% 4% 6%
10%
12%
All Boiler Measures
(9 month payback)
Boiler Load Management
(23 month payback)
Boiler Maintenance
(5 month payback)
Combustion Air Preheating
(8 month payback)
Boiler Blowdown
(11 month payback)
1 1 1
III III
Energy Savings Rate (percent of total facility energy use)
* Results from the DOE/IAC Database (1/90-7/97). The IAC data reflect average potential impacts from energy efficiency measures at small-to-medium sized manufacturing
facilities across all sectors and regions of the country. Most IAC audit recommendations are expected to be implemented within two years and typically have a one-to-two year
payback period. (See Chapter 1.)
2. Boilers
Wise Rules
Pages
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expected energy savings, eight percent of total energy use, but
these measures were only recommended at one percent of facilities
audited and have a payback of about two years. Boiler mainte-
nance measure were recommended at 16 percent of facilities audit-
ed with average energy savings of two percent and simple payback
time of only five months. Boiler Table 1, at the end of this chap-
ter, summarizes the Wise Rules presented in this chapter, along
with cost savings estimates, where available.
Boiler Load Management
One of the most basic energy saving measures is effective boiler
load management — properly sizing the boiler to meet the steam
load. A good example of this is replacing a large boiler with sever-
al smaller ones, allowing for high efficiency operation during light
and full load periods. The relationship between boiler efficiency
and firing rate is non-linear. Therefore, in order to maximize over-
all efficiency, a boiler's output can be matched to load, based on
its design and specifications.
Boiler Wise Rule 1
Effective boiler load management techniques, such
as operating on high fire settings or installing smaller
boilers, can save over 7% of a typical facility's total
energy use with an average simple payback of less
than 2 years.4
Boiler Wise Rule 2
Load management measures, including optimal
matching of boiler size and boiler load, can save
as much as 50% of a boiler's fuel use.5
Tune-Up and Air/Fuel Ratio
Optimization
Periodic measurement of flue gas oxygen, carbon monoxide, opac-
ity, and temperature provides the fundamental data required for a
boiler tune-up. It is useful to have the following instruments on
hand to best manage boiler operation: stack thermometers, fuel
meters, make-up feedwater meters, oxygen analyzers, run-time
recorders, energy output meters, and return condensate ther-
mometers.6 A typical tune-up might include a reduction of excess
air (and thereby excess oxygen, 02), boiler tube cleaning, and re-
calibration of boiler controls. Maintaining a proper air-to-fuel
ratio is very important for optimizing fuel combustion efficiency.
In a "lean" mix (high air-to-fuel ratio), heat will be lost to the
excess air, while in a "rich" mix (low air-to-fuel ratio), unburned
fuel will be emitted with the exhaust gases. Each fuel type and fir-
ing method has an optimal air/fuel ratio. For example, optimum
excess air for a pulverized coal boiler is 15 to 20 percent (3 to 3.5
percent excess 02), and optimum excess air for a forced draft gas
boiler is 5 to 10 percent (1 to 2 percent excess 02). The air/fuel
ratio should be set to the manufacturer's recommendations.
Because it is difficult to reach and maintain optimal values in most
boilers, actual excess air levels may need to be set higher than opti-
mal. When boilers are operating at low loads, excess-air require-
ments may be greater than the optimal levels and efficiency may
be lower.9 Manual or automatic oxygen trim can ensure that the
proper air/fuel mixture ratio is maintained. Secondary impacts of
boiler efficiency measures should be considered when evaluating a
project. For example, adjustments of air/fuel ratio and other oper-
ating parameters may affect emissions of nitrogen oxides, particu-
lates, or carbon monoxide.
Boiler Wise Rule 3
An upgraded boiler maintenance program including
optimizing air-to-fuel ratio, burner maintenance, and
tube cleaning, can save about 2% of a. facility's total
energy use with an average simple payback of 5
months.11
Boiler Wise Rule k
A comprehensive tune-up with precision testing
equipment to detect and correct excess air losses,
smoking, unburned fuel losses, sooting, and high
stack temperatures, can result in boiler fuel savings
of2%to20%.12
Boiler Wise Rule 5
A 3% decrease in flue gas 02 typically produces
boiler fad savings of 2%.13
Boiler Wise Rule 6
Using over fire draft control systems to control excess
air can save 2% to 10% of a boiler's fuel use with
typical equipment costs of $1,500.14
Page6
Wise Rules
2. Boilers
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Boiler Wise Rule 7
Using a characterizable fuel valve to match the
air/fuel ratios across the load range can save 2% to
12% of a boiler's fuel use at relatively low cost.15
Burner Replacement
The method by which fuel is delivered to the burner affects boiler
efficiency. Fuel atomization can add flexibility in fuel choice and can
improve low load operation. Atomizers suspend fine droplets of fuel
on a cone of air or steam allowing better control of fuel delivery16
Boiler Wise Rule 8
Converting to air or steam atomizing burners from
conventional burners can reduce boiler fuel use by
2% to 8%.17
Stack Heat Losses and
Waste Heat Recovery
Stack heat losses are usually the largest single energy loss in boil-
er operations. Key measures that minimize stack heat losses are
air/fuel ratio optimization (see above), and stack gas heat recov-
ery for pre-heating combustion air or boiler feedwater (see
Chapter 5). Heat recovery may increase boiler-operating tem-
perature, which may have secondary effects of increasing nitro-
gen oxide emissions. To maximize boiler efficiency and prevent
flue gas condensation, stack temperature should be 50°F to
100°F above the water temperature.
Boiler Wise Rule 9
Every 40°F reduction in net stack temperature (outlet
temperature minus inlet combustion air temperature)
is estimated to save 1% to 2% of a boiler's fuel use.20
Boiler Wise Rule 10
Stack dampers prevent heat from being pulled up the
stack and can save 5% to 20% of a boiler's fuel use.21
Boiler Wise Rule 11
Direct contact condensation heat recovery can save
8% to 20% of a boiler's fuel use, but costs may be rel-
atively high.22
Boiler Wise Rule 12
Preheating combustion inlet air can save about 3% of
a. facility's total energy use with an average simple pay-
back of 8 months.23
Blowdown Control and
Waste Heat Recovery
Dissolved and suspended solids in boiler feedwater can deposit on
heat transfer surfaces and reduce boiler efficiency. Boiler manufac-
turers usually establish a maximum acceptable concentration of
dissolved solids. To maintain low concentration levels, boiler water
is periodically diluted in a process called "blowdown" during
which boiler water is drained off and new water is added.2 Heat
losses during blowdown are often overlooked because they are
hard to measure and facility personnel may not fully understand
the water chemistry. Hot water drained to the sewer and excess
heat vented to the atmosphere contains unused energy.25 Warming
make-up feedwater with blowdown waste heat can minimize heat
losses. Replacing manual blowdown valves with analyzing equip-
ment and automatic valves can also reduce blowdown losses.
Boiler Wise Rule 13
Minimizing energy loss from boiler blowdown can
save about 2% of a. facility's total energy use with an
average simple payback of less than 1 year.26
Boiler Wise Rule U
Removing a 1/32 inch deposit on boiler heat transfer
surfaces can decrease a boiler's fuel use by 2%;
removal of a 1/8 inch deposit can decrease boiler fuel
use by over 8%.27'28
Boiler Wise Rule 15
Slowdown heat recovery is a proven technology that
can reduce a boiler's fuel use by 2% to 5%.29
Boiler Wise Rule 16
For every 11°F that the entering feedwater temperature
is increased, the boiler's fuel use is reduced by 1%.30
2. Boilers
Wise Rules
Page?
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Boiler Wise Rule 17
Changing from manual blowdown control to auto-
matic adjustment can reduce a boiler's energy use by
2% to 3% and reduce blowdown water losses by up
to 20%.31
Summary of Wise Rules for
Boiler Systems
Use the Wise Rules in Boiler Table 1 (next page) to identify and
estimate potential energy saving from boiler efficiency measures. In
selecting alternative efficiency options and eliminating less attrac-
tive measures, consider the potential costs, savings, payback times
and any secondary effects. When using the Wise Rules, remember
that several of the measures may overlap, or complement each
other (e.g., tune-up and flue gas 02 reduction) and energy savings
rates of overlapping measures may not be additive. In addition,
multiple Wise Rules may address the same measure from different
perspectives. For example Boiler Wise Rule 1 expresses savings
from boiler load management as a percent of the boiler's energy use,
while Boiler Wise Rule 2 expresses savings as a percent of the facil-
ity's total energy use. Specific Wise Rules may not be comparable
with each other because they rely on different sources with differ-
ent assumptions.
Adjust the Wise Rules in Boiler Table 1 to match your circum-
stances. For example, you may want to scale the gross fuel cost sav-
ings to match your boiler size. To calculate savings for a 10
MMBtu/hr natural gas boiler, multiply gross fuel cost savings by
a factor often. This scaling is applicable only to gross fuel cost sav-
ings expressed per MMBtu/hr, e.g., Rule 2, but not Rule 1 in
Boiler Table 1. Implementation costs may not scale in a linear
manner. Similarly, you can adjust the savings numbers on the basis
of your fuel prices and operating hours. For example, if your boil-
er uses coal at a price of $1.50/MMBtu, divide the cost savings
values in Boiler Table 1 by the per MMBtu price of natural gas,
e.g., $2.30, and multiply by $1.50.
Boiler System Notes
Rutgers University, Office of Industrial Productivity and Energy
Assessment, Modem Industrial Assessments: A Training Manual, Version
I.Ob, December 1995, p. 5-1.
2 O'Callaghan, P., Energy Management, McGraw-Hill, England, 1993,
p. 198.
3 Taplin, H.R., Boiler Plant and Distribution System Optimization Manual,
Fairmont Press, 1991, p. 122.
4 DOE/IAC Industrial Assessment Database, July 1997.
' Taplin, p. 122.
6 Taplin, p. 129.
' Turner, W.C., Energy Management Handbook, 3rd Edition, Fairmont
Press, 1997, p. 90.
8 Rutgers, p. 5-12.
9 Turner, p. 90.
1" Garay, P.N., Handbook of Industrial Power and Steam Systems, Fairmont
Press, 1995, p. 211.
11 DOE/IAC Database.
12 Taplin, p. 134.
" 3M Company, "Rules of Thumb: Quick Methods of Evaluating Energy
Reduction Opportunities," 1992, p. 8.
l4Taplin,p. 141.
15 Taplin, p. 140.
16 Taplin, p. 153.
17Taplin, p. 153.
18 Taplin, pp. 11-18.
19 Rutgers, p. 5-12.
20 Garay, p. 219; Taplin, p. 15; Rutgers, p. 5-2.
21 Taplin, p. 15.
22 Taplin, p. 166.
23 DOE/IAC Database.
24 Garay, p. 271.
25 Taplin, p. 13.
26 DOE/IAC Database.
27 Garay, p. 271.
28 Rutgers, p. 5-10.
29 Taplin, p. 160.
30 Taplin, p. 33.
31 Taplin, p. 161; Turner, p. 109.
Pages
Wise Rules
2. Boilers
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Boiler Table 1: Summary of Boiler Efficiency Measures
Source Measure
(IAC recommendation rale)
Average Energy Savings3
Average Annual Cost Savings
Savings per MMBIu/hr and (Payback)
Rulel
Rule 2
RuleS
Rule 4
RuleS
Rule 6
Rule?
RuleS
RuleS
Rule IS
Rule 11
Rule 12
Rule 13
Rule 14
Rule 15
Rule 16
Rule 17
All Efficiency Improvements
Implement typical efficiency
improvements, which may include
many or all of the measures below (20%)
Boiler Load Management
Operate on high fire setting
or install smaller boilers (1%)
Optimize boiler size and boiler load
Tune-Up and Air/Fuel Ratio Optimization
Implement boiler maintenance (air/fuel
ratio optimization, burner maintenance,
boiler tube cleaning) (16%)
Implement comprehensive tune-up
Decrease flue gas O2
Utilize over fire draft control
Utilize characterizable fuel valve
2.8% of total facility energy use
7.4% of total facility energy use*5
2% to 50%
2.4% of total facility energy usec
2% to 20%
2% per 3% decrease in O2
2% to 10%
2% to 12%
Burner Beplacement
Convert to atomizing burners
2% to 8%
Stack Losses and Waste Heat Becovery
Reduce w^stack temperature 1% to 2% per 40°F reduction
Utilize stack dampers 5% to 20%
Direct contact condensation heat recovery 8% to 20%
Preheat combustion air (3%) 2.6% of total facility energy use*5
Blowdown Control and Heat Becovery
Minimize boiler blow down (1%) 1.6% of total facility energy
Remove deposits from heat transfer surfaces 2% for 1/32 inch deposit,
8% for a 1/8 inch deposit
Utilize blowdown heat recovery 2% to 5%
Preheat boiler feedwater 1% per 11° F increase
Utilize automatic blowdown control 2% to 20%
$7,200 (9 months)15
$19,900 (23 months)15
$230 to $5,750C
$2,460 (5 months)15
$230 to $2,300C
$230'
$230 to $1,400C
$230 to $1,400C
$230 to $920C
$140 to $230C
$580 to $2,300C
$920 to $2,300C
$5,200 (8 months)15
$8,500 (11 months)15
$230 to $920C
$230 to $580C
$140C
$230 to $2,300C
Source references for each Wise Rule are included in the chapter notes.
Percent of boiler energy use, unless noted.
Energy savings are expressed as a percent of total facility energy use. Cost savings (fuel, O&M, etc.) are expressed in dollars, not in dollars per MMBtu/hr of boiler size.
Based on a natural gas boiler with 80% efficiency, operating 5,000 hrs/yr, with a gas price of »$2.30/MMBtu. These are gross fuel cost savings only and do not include
capital, maintenance, or other costs or savings.
2. Boilers
Wise Rules
-------
Introduction
Steam system efficiency improvements are a logical complement
to boiler efficiency measures. Useful energy escapes from steam
distribution systems from malfunctioning steam traps, steam
leaks, and via radiative losses from steam lines, condensate lines,
and storage tanks. Each of these areas presents opportunities for
energy savings.
Steam system efficiency measures that may be of interest to
Climate Wise Partners include: steam trap maintenance, repairing
steam leaks, insulation, condensate measures, and vapor recom-
pression. Steam Figure 1 illustrates the potential energy savings
from steam system efficiency measures based on specific recom-
mendations in the DOE/IAC database. Steam system efficiency
measures were recommended at 13 percent of the 4,300 facilities
audited with an average anticipated savings of two percent of a
facility's total energy use and a simple payback of six months.
Improved steam line insulation was recommended at seven per-
cent of the facilities audited with an expected average savings of
one percent of the facility's total energy use and a simple payback
often months. Steam Table 2, at the end of this chapter, summa-
rizes the Wise Rules presented in this chapter, along with cost sav-
ings estimates, where available.
Maintenance of Steam Traps
Steam traps hold steam in the coil until the steam releases its heat
energy and condenses. Steam trap operation can be checked by
comparing the temperature on each side of the trap. In properly
Steam Figure 1
Energy Savings from Steam System Efficiency Measures*
Recommendation Rate
0% 1% 2% 3%
4%
8%
9%
10%
11% 12%
All Steam Measures
(6 month payback)
Steam Trap Maintenance
(2 month payback)
Repair Steam Leaks
(3 month payback)
Insulate Steam Lines
(10 month payback)
Condensate Measures
(8 month payback)
Recommendation Rate
Energy Savings
1% 2%
Energy Savings Rate (percent of total facility energy use)
* Results from the DOE/IAC Database (1/90-7/97). The IAC data reflect average potential impacts from energy efficiency measures at small-to-medium sized manufacturing
facilities across all sectors and regions of the country. Most IAC audit recommendations are expected to be implemented within two years and typically have a one-to-two year
payback period. (See Chapter 1.)
Page 10
Wise Rules
3. Steam Systems
-------
functioning steam traps, there will be a large temperature differ-
ence between the two sides of the trap and no steam downstream
of the trap. Malfunctioning steam traps waste steam and result in
higher boiler fuel consumption. Typically, 15 to 60 percent of the
steam traps in a plant may be malfunctioning and wasting large
amounts of energy.
Steam Wise Rule 1
An effective steam trap maintenance program can
save 3% of a. facility's total energy use with an average
simple payback of 2 months.3
Steam Wise Rule 2
An effective steam trap maintenance program can
reduce a boiler's fuel use by 10% to 20%.
Reducing Leaks
Repairing leaks in steam pipes, condensate return lines, and fit-
tings can yield significant energy and cost savings. Steam leaks
increase boiler fuel use because additional steam must be generat-
ed to make up for the wasted steam. Leaky condensate return lines
increase make-up water requirements and increase boiler fuel use
because more energy is required to heat the cooler, make-up
boiler feedwater than would be required to heat the returned con-
densate. Actual savings will depend on boiler efficiency, steam
pressure, and annual operating hours.
Steam Wise Rule 3
Repairing steam system leaks can save 1% of a
facility's total energy use with an average simple
payback of 3 months.6
Steam Wise Rule k
A single high-pressure steam leak (125 psi) can result
in energy losses costing from $660 to $2,200 per year
(8,760 hrs). A single low-pressure steam leak (15 psi)
can result in energy losses costing $130 to $480 per
year (8,760 hrs).7
Reducing Heat Losses
Often boiler and steam system insulation is removed to make
repairs and is not replaced. Uninsulated surfaces in boiler and
steam systems can reach 450°E Such high temperatures can
threaten employee safety and can pose a fire hazard, as well as
waste significant amounts of energy.
Steam Table 1
Annual Costs of Heat Loss per 100 feet of
Uninsulated Steam Pipe8
Steam Pressure
25 psi
Cost pen 100 ft of
pipe per year (8,760 hr)
50 psi
$1,900
75 psi
$2,100
100 psi
$2,300
Steam Wise Rule 5
Insulating steam lines can save 1% of a. facility's total
energy use with an average simple payback of 10
months.9
Vapor Recompression
When there is a need for low pressure steam, vapor recompression
can double the pressure of vented steam using only a fraction of
the energy required to generate the steam in a boiler.
Steam Wise Rule 6
Vapor recompression saves 90% to 95% of the energy
needed to raise the steam to the same pressure in a
boiler.11
Condensate
A number of measures can be implemented to reduce heat losses
from condensate — the water that forms after steam has been
used. Increasing the amount of condensate returned to the boiler
saves energy because it eliminates the need to heat cold make-up
water. Insulating steam lines, condensate lines and tanks, will pre-
3. Steam Systems
Wise Rules
Page 11
-------
vent unnecessary heat loss through the system. Collecting high-
pressure condensate after flash steam formation can provide low-
pressure steam for other purposes.
Steam Wise Rule 7
^^^^^^^^^^^H
Measures to reduce heat loss from condensate in a
steam system can save over 1% of a. facility's total ener-
gy use with an average simple payback of 8 months.12
Summary of Wise Rules for
Steam Systems
Use the Wise Rules in Steam Table 2 (next page) to identify and
estimate potential energy saving from steam system efficiency
measures. When identifying attractive options and eliminating
weak ones, consider potential costs, savings, payback periods and
any secondary effects. When using the Wise Rules, remember that
some measures may interact or complement each other (e.g.,
steam trap maintenance and steam pipe insulation) and energy
savings rates may not be additive. Multiple Wise Rules may
address the same efficiency measure from different perspectives.
For example, Steam Rules 1 and 2 express savings from steam trap
maintenance as (1) a percent of a facility's total energy use, and (2)
as a percent of boiler energy use.
Steam System Notes
1 Rutgers University Office of Industrial Productivity and Energy
Assessment, Modern Industrial Assessments: A Training Manual, Version
1.Ob, December 1995, p. 5-19.
Turner, W.C., Energy Management Handbook, 3rd Edition, Fairmont Press,
1997, p. 149.
3 DOE/IAC Industrial Assessment Database, July 1997.
*Taplin, H.R., Boiler Plant and Distribution System Optimization Manual,
Fairmont Press, 1991, p. 276.
' Rutgers, p. 5-17.
6 DOE/IAC Database.
' Rutgers University OIPEA, "Useful Rules of Thumb for Resource
Conservation and Pollution Prevention," March 1996, #1 and #2.
8 Rutgers, "Useful Rules of Thumb,"#8.
9 DOE/IAC Database.
Bonneville Power Administration (BPA), Washington State Energy Office,
Electric Ideas Clearinghouse, "Vapor Recompression," July 1992, p. 1.
11 BPA, p. 1.
12 DOE/IAC Database.
Page 12
Wise Rules
3. Steam Systems
-------
Steam Table 2: Summary of Steam System Efficiency Measures
Source Measure
(IAC recommendation rale)
Rulel
Rule 2
RuleS
Rule 4
Table 1
RuleS
Rule 6
Rule?
Average Energy Savings
Average Annual Cost Savings
(payback)
All Efficiency Improvements
Implement typical efficiency
improvements, which may include
many or all of the measures below (13%)
2% of total facility energy use
$7,100 (6 months)
Steam Trap Maintenance
3.4% of total facility energy use
Implement steam trap
maintenance program (1%)
Implement steam trap maintenance program 10% to 20% of boiler fuel use
Leak Repair
Repair steam leaks (2%)
Repair high pressure leaks (125 psi)
Repair low pressure leaks (15 psi)
$17,400 (2 months)
10% to 20% of boiler fuel costs
Insulate steam lines (7%)
Improve steam line insulation
Other Measures
Recompress low pressure steam
Reduce heat loss from condensate (4%)
1.0% of total facility energy use
$6,100 (3 months)
$660 to $2,200 per leak
$130 to $480 per leak
1.0% of total facility energy use
$1,600 to $2,300 per 100 feet
$2,800 (10 months)
90% to 95% of energy needed to
raise the steam in a boiler
1.3% of total facility energy use
$6,700 (8 months)
Source references for each Wise Rule are included in the chapter notes.
3. Steam Systems
Wise Rules
-------
Introduction
Industrial companies use furnaces, ovens, and kilns to raise the
temperature of a raw material or intermediate product as part of
a manufacturing process. Important process heating efficiency
measures include: insulation, combustion air control, burner
adjustment, automatic stack dampers, waste heat recovery, tem-
perature optimization, use of minimum safe ventilation, immer-
sion heating, and enhanced sensitivity of temperature control and
cutoff. Minimizing equipment heat-up time can also save energy.
For example, many ovens need only 15 to 60 minutes to heat up,
but, in practice, may "warm up" for an unnecessarily long period
of time. The remainder of this chapter provides additional infor-
mation on heat containment, process heating and direct heating.
Process Heating Figure 1 illustrates the potential energy savings
from heating efficiency measures based on IAC audit recommen-
dations. Furnace efficiency measures were recommended at four
percent of the facilities audited with estimated average savings of
three percent of the average facility's total energy use and a simple
payback of eight months. Heat recovery from ovens, kilns, and
other equipment was recommended during only one percent of
the audits with estimated energy savings of almost five percent and
average simple payback of 16 months. Process Heating Table 1,
at the end of this chapter, summarizes the Wise Rules presented in
this chapter, along with cost savings estimates, where available.
Insulation and Heat Containment
Heat loss can cause major reductions in process heating efficiency.
Heat containment measures include insulation of bare equipment
and open tanks, isolating hot or cold equipment from air condi-
tioned areas, and reducing infiltration into hot or cold process
equipment. New refractory fiber material, with low thermal con-
ductivity and heat storage, can produce significant improvements
in efficiency with minimal detriment to the work environment.
Typical applications include furnace covers, installing fiber liner
between the standard refractory lining and the shell wall, or
installing ceramic fiber linings over the present refractory liner.
Replacing standard refractory linings with vacuum-formed refrac-
tory fiber insulation can also improve efficiency.
Process Heating Figure 1
Energy Savings from Process Heating Efficiency Measures*
Recommendation Rate
0% 1%
All Furnace Heating Measures
(Smonth payback)
Oven/Kiln Heat Recovery
(16 month payback)
All Process Heating Measures
(7 month payback)
0% 1% 2% 3%
Energy Savings Rate (percent of total facility energy use)
* Results from the DOE/IAC Database (1/90-7/97). The IAC data reflect average potential impacts from energy efficiency measures at small-to-medium sized manufacturing
facilities across all sectors and regions of the country. Most IAC audit recommendations are expected to be implemented within two years and typically have a one-to-two year
payback period. (See Chapter 1.)
Page 14
Wise Rules
4. Process Heating
-------
Process Healing Wise Rule 1
Proper heat containment can save about 2% of a
facility's total energy use with an average simple
payback of 9 months.3
Process Healing Wise Rule 2
Insulating a furnace with refractory fiber liners can
improve the thermal efficiency of the heating process
by up to 50%.4
Combustion Air Control
Maintaining a proper air-to-fuel ratio is very important for opti-
mizing fuel combustion efficiency in process heating. In a "lean"
mix (high air-to-fuel ratio), heat will be lost to the excess air, while
in a "rich" mix (low air-to-fuel ratio), unburned fuel will be emit-
ted with the exhaust gases. Aspirators can help maintain a proper
air-to-fuel ratio for premix burners systems, while ratio-regulating
systems can do this for nozzle mix burners. Automatic burner
control is also an effective strategy for optimizing the air-to-fuel
ratio. Control systems technologies include programmable logic
controllers, direct stack temperature monitors, and intelligent
high-level computer controllers. Be sure to consider potential sec-
ondary impacts from adjustments of air/fuel ratio or other operat-
ing parameters, such as changes in emissions of nitrogen oxides,
particulates, and carbon monoxide.
Process Waste Heat Recovery
Exhaust gas heat losses are another source of process efficiency
loss. Heat recovery systems can recapture this heat and reintro-
duce it into processing heat or other end-uses. A recuperator
extracts heat from furnace waste gases to preheat incoming com-
bustion air. A regenerator uses porous ceramic beds for waste gas
heat recovery and short-term heat storage. Chapter 5, "Waste
Heat Recovery and Cogeneration," describes additional waste
heat recovery measures.
Process Healing Wise Rule 3
Recovering waste heat from furnaces, ovens, kilns,
and other equipment can save 5% of a typical facility's
total energy use with an average simple payback of
16 months.8
Process Healing Wise Rule k
Recovering waste heat through a recuperator can
reduce a kiln's energy use by up to 30%; regenerators
can save up to 50%.9'10
Specific Process Heat Applications
Energy savings opportunities available in some sectors may be
more broadly applicable. For example, in the lumber industry, air-
drying lumber before putting it in the kiln can reduce kiln energy
use. Using variable speed controls to reduce kiln fan power after
the water has been driven off can significantly reduce kiln energy
use without affecting drying time or product quality. In the
cement industry, advanced control systems such as automated
controls and expert systems have shown significant energy savings.
Optimizing heat transfer conditions in the clinker cooler through
better distribution of clinker and air can also result in substantial
energy savings.
Process Healing Wise Rule 5
Each percent of moisture removed by air drying
lumber reduces the kiln's energy use by 50 to 85 Btu
per board foot.12
Process Healing Wise Rule 6
Variable fan speed control in the lumber industry
can reduce dry kiln airflow by 20% and reduce the
kiln's energy used during surface drying by as much
as 50%.13
Process Healing Wise Rule 7
Installing expert systems for kiln secondary control
can reduce a cement kiln's energy use by up to 3%.14
Process Healing Wise Rule 8
New clinker cooler technologies that optimize heat
transfer conditions can reduce a cement kiln's energy
use by up to 6%.15
4. Process Heating
Wise Rules
Page 15
-------
Direct Heating
Direct heating is generally more efficient than indirect heating
because heat transfer losses from equipment and transfer media
are eliminated. Examples of direct heating technologies include
direct firing (generally with natural gas), infrared, microwave,
and dielectric heating. Direct heating also provides other opera-
tional benefits including faster drying times, reduced mainte-
nance, easier installation, more precise temperature control,
more uniform heating, and increased output.16
Process Healing Wise Rule 9
Direct firing with natural gas in place of indirect
steam heating has the potential to save 33% to 45%
of process heating energy use. Payback times may range
from a few months to 6 years.17
Process Healing Wise Rule 10
Direct electric heating (infrared, microwave, or dielec-
tric) can reduce process heating energy use by up to
80% with typical payback periods of 1 to 3 years.18
Summary of Wise Rules for
Process Heating
Use the Wise Rules in Process Heating Table 1 (next page) to
identify and estimate potential energy savings from process heat-
ing efficiency measures. When evaluating alternatives and elimi-
nating options, consider the potential costs, energy savings, pay-
back time, and any secondary effects. When using the Wise
Rules, remember several of the measures may overlap or comple-
ment each other and energy savings rates from overlapping mea-
sures may not be additive. In addition, multiple Wise Rules may
express savings for similar measures from different perspectives.
For example, some express energy savings in terms of a typical
facility's total energy use, while others are expressed in terms of
an end use's energy consumption.
Process Heating Notes
3M Company, "Laboratory Operations Energy Efficiency Guidelines,"
Feb. 1994.
2 Rutgers University Office of Industrial Productivity and Energy
Assessment, Modem Industrial Assessments: A Training Manual, Version
1.Ob, December 1995, p. 5-36.
3 DOE/IAC Industrial Assessment Database, July 1997.
Rutgers, p. 5-37.
' Rutgers, p. 5-34.
° Centre for the Analysis and Dissemination of Demonstrated Energy
Technologies (CADDET), "Learning from Experiences with Process
Heating in the Metals Industry," Analyses Series No. 11, 1990.
7 CADDET, 1990.
8 DOE/IAC Database.
' Bonneville Power Administration (BPA), Washington State Energy Office,
Electric Ideas Clearinghouse, "Dry Kiln Retrofit/Replacement," October
1991.
10 CADDET, 1990.
11 BPA, "Dry Kiln Retrofit/Replacement."
Bonneville Power Administration (BPA), Washington State Energy Office,
Electric Ideas Clearinghouse, "Optimizing Dry Kiln Operation," October
1991.
13 BPA, "Dry Kiln Retrofit/Replacement."
ICF Kaiser Consulting Group estimate based on cement industry data.
I' ICF Kaiser Consulting Group estimate based on cement industry data.
Mercer, A., Learning from Experience with Industrial Drying Technologies,
Centre for the Analysis and Dissemination of Demonstrated Energy
Technologies (CADDET), 1994.
17 Mercer, pp. 25-38.
18 Mercer, pp. 39-54.
Page 16
Wise Rules
4. Process Heating
-------
Process Heating Table 1: Summary of Process Heating Efficiency Measures
Source
Rulel
Rule 2
RuleS
Rule 4
RuleS
Rule 6
Rule?
RuleS
RuleS
Rule IS
Measure
(IAC recommendation rate)
All Efficiency Improvements
Implement typical efficiency
improvements, which may include
many or all of the measures below (4%)
Average Energy Savings
Insulation and Heat Containment
Improve heat containment (22%)
Install fiber insulation
Process Heating Waste Heat Recovery
Recover furnace, oven, and kiln
waste heat (1%)
Recover heat from kilns
Specific Process Heating Applications
Air dry lumber
Install variable speed drives (VSD)
for dry kiln airflow
Install expert systems for
secondary kiln controls
Optimize heat transfer conditions
Direct Heating
Use direct firing with natural
gas in place of indirect heating
Use direct electric heating in
place of indirect heating
Average Annual Cost Savings
(payback)
2.8% of total facility energy use
$8,100 (8 months)
1.5% of total facility energy use $5,100 (9 months)
50% improvement in thermal efficiency
4.6% of total facility energy use $13,000 (16 months)
30% to 50% reduction in kiln energy use
50 to 85 Etufer boardfootfoi each
1% moisture removed
up to 50% of kiln energy use
up to 3% of cement kiln
energy use
up to 6% of cement kiln energy use
33% to 45% of the energy
requirement
80% of heating energy use
(few months to 6 years)
(1 to 3 years)
Source references for each Wise Rule are included in the chapter notes.
4. Process Heating
Wise Rules
Page 17
-------
Introduction
Heat exchangers recover useful energy that would ordinarily be
lost. Generally, a heated gas or liquid leaving a process passes
through a heat exchanger to preheat another gas or liquid entering
a process or an HVAC system. Cogeneration takes heat recovery a
step further by recovering heat that would normally be wasted in
the process of power generation and steam production.
Cogeneration systems can reach efficiencies that can triple, or even
quadruple, conventional power and steam generation. Heat
Recovery/Cogen Figure 1 illustrates the potential energy savings
from heat recovery and Cogeneration measures based on IAC audit
recommendations. Waste heat recovery measures were recom-
mended at 26 percent of the 4,300 IAC audits conducted from
1990 through mid-1997 and were estimated to save almost five
percent of the average facility's total energy use with a simple pay-
back of 16 months. Cogeneration was recommended at fewer facil-
ities (three percent), but the average expected energy savings were
much higher (nine percent of the facility's energy use, including
fuel inputs at off-site powerplants for purchased electricity) and the
payback was about three years. Heat Recovery/Cogen Table 2, at
the end of this chapter, summarizes the Wise Rules presented in
this chapter, along with cost savings estimates, where available.
Waste Heat Recovery
Heat recovery is often a viable retrofit option for existing equipment.
Ventilation and exhaust from process heating or combustion equip-
ment are some common sources of potentially recoverable energy.
Heat recovery is beneficial only if the heat can be used elsewhere and
if it is available when it is needed. Typical applications of waste heat
include process heating, combustion air preheating, boiler feedwater
preheating, and space heating. Be sure to consider any secondary
effects from adjustments of combustion parameters, such as emis-
sions of nitrogen oxides, particulates, and carbon monoxide.
Heat Recovery/Cogen Figure 1
Energy Savings from Heat Recovery and Cogeneration Efficiency Measures*
Recommendation Rate
0% 3% 6%
9%
24%
24%
Waste Heat Recovery
(16 month payback)
Cogeneration**
(34 month payback)
Heat Containment
(9 month payback)
Recommendation
Rate
Energy
Savings
2%
Energy Savings Rate (percent of total facility energy use)
* Results from the DOE/IAC Database (1/90-7/97). The IAC data reflect average potential impacts from energy efficiency measures at small-to-medium sized manufacturing
facilities across all sectors and regions of the country. Most IAC audit recommendations are expected to be implemented within two years and typically have a one-to-two year
payback period. (See Chapter 1.)
** Cogeneration energy savings are based on primary fuel savings from electricity generation, including fuel inputs at off-site powerplants for purchased electricity. Off-site
power generation is assumed to have a heat rate of about 10,000 Btu/kWh. Savings are calculated by dividing total energy savings, including powerplant inputs, by total
facilityenergy use.
Page 18
Wise Rules
5. Heat Recovery & Cogeneration
-------
Heal Recovery/Cogen Wise Rule 1
Recovering waste heat can reduce a typical facility's
total energy use by about 5% with an average simple
payback of 16 months.2
Heat Recovery/Cogen Wise Rule 2
Reducing net stack temperature (outlet temperature
minus inlet combustion air temperature) by 40°F is
estimated to reduce the boiler's hid use by 1% to 2%.3
Heal Recovery/Cogen Wise Rule 3
Preheating furnace combustion air with recovered
waste heat can save up to 50% of the furnace's energy
use. Heat Recovery/Cogen Table 1 summarizes typi-
cal fuel savings for a natural gas furnace.4
Air-to-air heat exchangers transfer heat from a hot air stream to a
cold one. Using air-to-air heat exchangers to preheat ventilation
air in the winter or for precooling in the summer can add to the
air distribution systems pressure losses and may require larger ven-
tilation fans.6 In heat pipes, hot and cold air streams flow in oppo-
site directions. Heat pipes typically are used in the range of 150°F
to 850°F and recover between 60 and 80 percent of the heat from
the exhaust air stream. Heat wheels are porous disks with high
heat capacity that rotate between a cold-gas duct and a hot-gas
duct. They can recover from 70 to 90 percent of the heat from the
Heat Recovery/Cogen Table 1 s
Fuel Savings from Preheating Combustion Air
Furnace Outlet Combustion Air
Temperature 400°F 600°F
2600°F
2400°F
2200°F
2000°F
1800°F
1600°F
1400°F
22%
18%
16%
14%
13%
11%
10%
30%
26%
23%
20%
19%
17%
16%
Preheat Temperature
800°F 1000°F 1200°F
37%
33%
29%
26%
24%
22%
20%
43%
38%
34%
31%
29%
26%
25%
48%
43%
39%
36%
33%
30%
28%
exhaust air stream. Glass fiber ceramic heat wheels can be used at
temperatures up to 2,000°F.7 Economizers are used primarily to
preheat boiler feedwater with flue gas waste heat. The boiler feed-
water flows through the economizer and is heated by the hot
exhaust gases from the boiler. The higher the waste gas tempera-
ture, the greater the possible energy savings. Economizers can be
used at gas temperatures up to 1,800°F.
Heal Recovery/Cogen Wise Rule k
Using an economizer to capture flue gas waste heat
and preheat boiler feedwater can reduce a boiler's fuel
use by up to 5%.9
Heat exchanger efficiency is directly proportional to the surface
area that separates the heated and cooled fluids. If heat exchanger
surfaces become fouled with films, deposits, or corrosion,
exchanger efficiency suffers. If heavy fouling is expected, contam-
inated streams may need to be filtered, or the design may need to
be modified to include different materials or to allow easy access
to surfaces for frequent cleaning.
Heal Recovery/Cogen Wise Rule 5
Removing a 1/32 inch deposit on boiler's heat transfer
surfaces can reduce a boiler's energy use by 2%;
removing a 1/8 inch deposit can reduce a boiler's
energy use by over 8%.n'12
Degeneration
Cogeneration is the simultaneous production of electric power
and thermal energy from a single fuel. In a typical configuration,
an industrial boiler is replaced by a gas turbine. The turbine is
used to generate electricity, and the waste heat is used to generate
steam in a heat recovery steam generator (or HRSG). Other
cogeneration configurations combine boilers and steam turbines,
or gas turbines and steam turbines (combined cycle units). Two
emerging technologies that are applicable to cogeneration are the
use of fuel cells and the Kalina cycle — a vapor heat engine cycle
using an ammonia-water working fluid.
Cogeneration is often a more efficient way of providing electrici-
ty and process heat than producing them independently given the
overall efficiency gain, as well as a potential fuel shift. Average effi-
ciencies for traditional cogeneration systems can range from 70
Based on a natural gas furnace with 10% excess air.
5. Heat Recovery & Cogeneration
Wise Rules
Page 19
-------
percent to more than 80 percent. Cogeneration makes most
sense in facilities where steam and electrical demand are balanced
with the typical output of the cogeneration unit.
There are generally economies of scale involved with cogeneration
systems, with larger units having lower costs (per installed kW)
and higher efficiencies. Average-sized cogeneration units range
from 10 to 50 MW, though units as small as 3 MW can be cost-
effective. Cogeneration economics depend on system utiliza-
tion. Therefore, it is important to closely match the system's
output to the facility's steam and electrical load. When electricity
production is in excess of on-site consumption needs, it can typi-
cally be sold to others and should be accounted for when evaluat-
ing the feasibility and economics of cogeneration. It is a good idea
to examine the steam load prior to assessing electrical needs in
evaluating a potential cogeneration project. Be sure to consider
any secondary impacts from new combustion equipment such as
nitrogen oxide emissions from gas turbines.
Heat Recovery/Cogen Wise Rule 6
Gas turbines with heat recovery equipment typically
cost from $600 to $l,000/kW. Larger gas turbines
may be available for half the cost per kW.17
Heat Recovery/Cogen Wise Rule 7
A typical cogeneration project may reduce primary
energy consumption (including fuel inputs at off-site
powerplants for purchased electricity) for steam and
electricity generation by 10% to 15%.18
Heat Recovery/Cogen Wise Rule 8
Cogeneration systems can save about 9% of a typical
facility's primary fuel inputs for on-site energy use
(i.e., including fuel savings at off-site powerplants for
purchased electricity) with an average simple payback
of 34 months.19 (Savings are calculated by dividing
total energy savings, including powerplant inputs, by
total facility energy use.)
Summary of Wise Rules for Waste
Heat Recovery and Cogeneration
Use the Wise Rules in Heat Recovery/Cogen Table 2 (next page) to
identify and estimate potential energy saving from heat recovery and
cogeneration. Consider potential costs, savings, payback time, and
any secondary effects in order to analyze different efficiency alterna-
tives and eliminate less attractive options. When using the Wise
Rules, remember that several of the measures may interact or com-
plement each other and energy savings rates may not
be additive.
Waste Heat Recovery and Cogeneration Notes
1 Rutgers University Office of Industrial Productivity and Energy
Assessment, Modem Industrial Assessments: A Training Manual, Version
I.Ob, December 1995, pp. 5-21 and 5-22.
2 DOE/IAC Industrial Assessment Database, July 1997.
^ Garay, P.N., Handbook of Industrial Power and Steam Systems, Fairmont
Press, 1995, p. 219; Taplin, H.R., Boiler Plant and Distribution System
Optimization Manual, Fairmont Press, 1991, p. 15; Rutgers, p. 5-2.
Rutgers, p. 5-21.
' Rutgers, p. 5-21.
° Bonneville Power Administration (BPA), Washington State Energy Office,
Electric Ideas Clearinghouse, "Exhaust Air Heat Recovery Systems," May
1992, p. 1.
7 Rutgers, p. 5-23.
8 Rutgers, p. 5-22.
° O'Callaghan, P., Energy Management, McGraw-Hill, England, 1993,
p. 198.
Turner, W.C., Energy Management Handbook, 3rd Edition, Fairmont Press,
1997, pp. 207-208.
11 Garay, p. 271.
12 Rutgers, p. 5-10.
^ Orlando, J.A., Cogeneration Design Guide, American Society of Heating,
Refrigerating and Air-Conditioning Engineers, Inc., 1996, pp. 62-63.
Stromberg, Jan, Gas-Turbine-Based CHP in Industry, Centre for the
Analysis and Dissemination of Demonstrated Energy Technologies (CAD
DET), 1993, p. 6.
' Mclntire, Margaret E., "Trigen Dispersed Energy Services for the Mid-
Sized Industrial and Commercial Market," Nineteenth National Industrial
Energy Technology Conference Proceedings, 1997, pp. 117-124.
Payne, F.W., Cogeneration Management Reference Guide, Fairmont Press,
Inc., 1997, p. 6.
17 Rutgers, p. 5-40.
ICF Kaiser Consulting Group estimate.
' DOE/IAC database. Off-site power generation is assumed to have a heat
rate of about 10,000 Btu/kWh.
Page 20
Wise Rules
5. Heat Recovery & Cogeneration
-------
Heat Recovery/Cogen Table 2: Summary of Heat Recovery and Cogeneration Efficiency Measures
Source
Measure
(IAC recommendation rate)
Rulel
Rule 2
RuleS
Rule 4
RuleS
Rule 6
Rule?
RuleS
Average Energy Savings'
Waste Heat Recovery
Recover waste heat (26%)
Reduce stack waste heat losses
Preheat furnace combustion air
Preheat boiler feedwater
Clean heat exchangers
Cogeneration
Install gas turbine Cogeneration
Install Cogeneration system
Install Cogeneration system (3%)
4.6% of total facility energy use
1% to 2% per 40°F reduction
Up to 50%
up to 5% of boiler energy use
2% for 1/32 inch deposit,
8% for a 1/8 inch deposit
verage Annual Cost Savings
(payback)
$12,500 (16 months)
Capital Cost: $600-$l,000/kW
10% to 15% of primary energy consumption
9.1% of total facility energy use**
$233,600 (34 months)
Source references for each Wise Rule are included in the chapter notes.
* Percent of equipment energy use, unless noted.
** Cogeneration energy savings are based on primary fuel savings from electricity generation, including fuel inputs at off-site powerplants for purchased electricity.
power generation is assumed to have a heat rate of about 10,000 Btu/kWh. Savings are calculated by dividing total energy savings, including powerplant inputs.
facility energy use.
Off-site
by total
5. Heat Recovery & Cogeneration
Wise Rules
Page 21
-------
Introduction
Compressed air is used to power tools and machines, to regu-
late HVAC systems, and for drying or cleaning various items.
The two main types of air compressors are reciprocating com-
pressors and screw compressors. Screw compressors generally use
more energy than reciprocating compressors, especially when
they are oversized. Compressor energy use is a function of many
variables including compressor type, part-load efficiency, and
control mechanisms.
Several compressed air system efficiency measures may be of inter-
est to Climate Wise Partners, including using cooler intake air,
optimizing load, reducing pressure, eliminating or reducing air
use, repairing leaks, recovering waste heat, replacing filters, and
cleaning coolers. Typical energy savings for these types of air com-
pressor measures are illustrated in Compressed Air Figure 1, based
on specific recommendations in the DOE/IAC database. Air com-
pressor efficiency measures can be made at most facilities and were
Compressed Air Fiyurc 1
Energy Savings from Air Compressor Efficiency Measures"
Recommendation Rate
10% 20%
Entire Compressed Air System
(5 month payback)
Using Cooler Intake Air
(5 month payback)
Upgrading Screw
Compressor Controls
(8 month payback)
Compressor Pressure
Reduction
(4 month payback)
Eliminating or Reducing
Compressed Air Use
(6 month payback)
Repairing Air Leaks
(3 month payback)
Air Compressor Waste
Heat Recovery
(10 month payback)
Recommendation Rate
Energy Savings
0.3% 0.6% 0.9%
Energy Savings Rate (percent of total facility energy use)
* Results from the DOE/IAC Database (1/90-7/97). The IAC data reflect average potential impacts from energy efficiency measures at small-to-medium sized manufacturing
facilities across all sectors and regions of the country. Most IAC audit recommendations are expected to be implemented within two years and typically have a one-to-two year
payback period. (See Chapter 1.)
Page 22
Wise Rules
S. Compressed Air Systems
-------
recommended at 68 percent of the 4,300 IAC audits conducted
from 1990 to mid-1997. Using cooler intake air and repairing air
leaks were recommended at more than a third of facilities audited.
Average expected savings are relatively small — less than a half
percent of a facility's total energy use. However, these measures
tend to have relatively short payback periods (about 5 months)
and reduce electricity use, a relatively expensive energy source with
high C02 emission rates in many regions. Some measures have
higher impacts. For example, air compressor waste heat recovery
can reduce facility energy use by almost two percent. Compressed
Air Table 2, at the end of this chapter, summarizes the Wise Rules
presented in this chapter, along with cost savings estimates, where
available.
The range of compressor efficiency measures is broad. Air com-
pressor energy use may represent 5 to 15 percent of a typical facil-
ity's energy use, depending upon process needs.
Compressed Air Wise Rule 1
Efficiency improvements can reduce compressed air
system energy use by 20% to 50%.2
Compressed Air Wise Rule 2
Efficiency improvements to compressed air systems
can save approximately one-half percent of a. facility's
total energy use.3
Use Cooler Intake Air
The amount of energy required to compress air is a function of the
intake air temperature, with warm air requiring more energy to
compress than cool air. There is a potential for energy savings
when cooler air, typically from outside, is used in place of warmer
compressor room air. Often piping can be installed to supply cool-
er outside air to the compressor intake. Energy and cost savings
for this measure will depend on compressor size, load factor, and
the number of hours of operation.4
Compressed Air Wise Rule 3
Using cooler intake air for compressors can reduce
compressed air system energy use by 1% per 5°F reduc-
tion in intake air temperature.5 The payback period
for this measure is usually less than two years.6
Compressed Air Wise Rule k
Using cooler intake air for compressors can save
almost one-half percent of a. facility's total energy use
with an average simple payback of 5 months.7
Match Compressor with
Load Requirement
Matching the compressor size with load can result in significant
energy savings. Because air compressors can consume 16 to 100 per-
cent of full load power at low loads, it is a good idea to optimize
compressor loading to minimize operation at low output levels.
This optimization can be achieved with unloading controls, auto-
matic shutdown timers, and manual or automatic compressor
sequencing. Unloading controls cost about $500 to install at the
factory and about $1,000 to retrofit; automatic on/off timers cost
about $300 to install. You might also consider purchasing a small
compressor for smaller loads to avoid low-load operation of a large
9
compressor.
Compressed Air Wise Rule 5
Installing or adjusting unloading controls can reduce
compressed air system energy use by about 10%.10
Compressed Air Wise Rule 6
Upgrading controls on screw air compressors can
reduce a. facility's total energy use by about 1% with
an average simple payback of 8 months.11
Reduce Compressor Air Pressure
Air is often compressed to a higher pressure than required by the
process equipment. Lowering air pressure reduces compressor
demand and energy use. Be sure to determine the minimum
required pressure before implementing this measure. Consider
reducing compressor operating pressure if it is higher than 10 psi
above that required by the process equipment (except with long
delivery lines or high pressure drops). Energy savings depend on
the compressor type, power rating, load factor, use factor, horse-
power reduction factor, and the proposed pressure change.13
6. Compressed Air Systems
Wise Rules
-------
Compressed Air Wise Rule 7
Reducing air compressor pressure can reduce a facili-
ty's total energy use by about one-half percent with an
average simple payback of 4 months.14
Compressed Air Wise Rule 8
Reducing air compressor pressure by 2 psi can reduce
compressor energy use by 1% (at 100 psi).15
Reduce or Eliminate
Compressed Air Use
In some facilities, compressed air use can be reduced or eliminated
entirely. Less expensive alternatives may exist for processes such as
cooling, agitating liquids, or moving products. In addition, some
air-powered tools (e.g., grinders) can be replaced by high frequen-
cy electric tools. Reducing compressed air use may result in an exist-
ing compressor operating at reduced load and lower efficiency. If
the reductions are significant, you may need to re-optimize loading
sequence or controls, or change to a smaller compressor.
Compressed Air Wise Rule 9
Eliminating or reducing compressed air usage for cer-
tain activities can reduce a. facility's total energy use by
more than one-half percent, with an average simple
payback of 6 months.16
Compressed Air Table 1
Energy Losses and Cost Impacts of Compressed
Air System Leaks24
Hole Leak Rate Energy Loss Cost of
Diameter Wasted Energy
(inches) (cubic feet/min.) (kWhperyear) (dollars per year)
1/64"
1/32"
1/16"
1/8"
1/4"
3/8"
0.5
1.8
7.2
29.0
115.8
260.6
635
2,500
10,800
43,800
174,100
392,000
$20
$90
$350
$1,500
$5,900
$13,200
Based on a 115 psi system with 8,520 hours of compressor operation. Electricity
price is assumed to be $0.034 per kWh.
Eliminate Air Leaks
Compressed air distribution system leaks along piping, around
valves, fittings, flanges, hoses, traps, and filters can result in signif-
icant energy losses in manufacturing facilities. Typical leakage rates
range from two to 20 percent of system capacity. In poorly main-
tained systems, leakage rates can be as high as 40 percent. The
cost of compressed air leaks increases exponentially as the size of the
hole increases. Compressed Air Table 1 presents average energy
losses for air leaks of various sizes. Leaks are often audible when the
system is pressurized but equipment is not running (e.g., during
breaks or after hours). Where you suspect a slow leak, use a soapy
water solution or an ultrasonic detector to pinpoint its location.18
When repairing compressed air leaks, it is important to consider
the effect on compressor loading. If the reductions are significant,
you may need to re-optimize loading sequence or controls.
Compressed Air Wise Rule 10
Repairing air leaks can reduce compressed air system
energy use by 30% or more.19
Compressed Air Wise Rule 11
Repairing air leaks can reduce -A. facility's total energy
use by about one-half percent, with an average simple
payback of 3 months.20
Compressed Air Wise Rule 12
It takes approximately 2.5 to 5.0 kWh to compress
1,000 ft3 of air to 100 psi.21'22 Each psi reduction in
compressed air loss from the distribution system (at
100 psi), reduces the compressor's energy use by more
than one-half percent.23
Recover Waste Heat
Sixty to 90 percent of the energy of compression is available as
heat that can be recovered.25 Recovered waste heat may be used for
space heating or to supply heat to a manufacturing process. The
amount of heat energy that can be recovered depends on com-
pressor characteristics and use factor. Waste heat recovery will be
most cost-effective when the compressor is located near the
process in which the heat is to be used. Air compressors 100 hp
and larger are often cooled with water from a cooling tower. The
temperature of the water leaving the compressor cooling coils may
be high enough that heat can be extracted and applied elsewhere.
Page 24
Wise Rules
6. Compressed Air Systems
-------
For example, boiler feedwater could be preheated by the compres-
sor cooling water.
Compressed Air Wise Rule 13
Air compressor waste heat recovery can reduce & facil-
ity's total energy use by about 2% with an average
simple payback of 10 months.
Filters and Coolers
Compressed air system efficiency suffers as compressed air system
filters and coolers become soiled. When filters are obstructed with
pipeline contaminants, significant pressure drops can develop,
requiring an increase in compressor discharge pressure. As a result
of the pressure increase, air leaks will become more costly.
Compressed Air Wise Rule 14
For every 1 psi increase in air compressor pressure gained
by periodic filter changes, air compressor energy use is
reduced by about one-half percent.29 Changing dryer fil-
ters at 8 or 10 psi drop per filter can eliminate this waste.
Compressed Air Wise Rule 15
For every 11°F decrease in air compressor working tem-
perature, gained by careful maintenance of intercoolers,
air compressor energy use will decreased by 1%.30
Summary of Wise Rules for
Compressed Air Systems
Use the Wise Rules in Compressed Air Table 2 (next page) to iden-
tify and estimate potential energy saving from air compressor effi-
ciency measures. When evaluating efficiency options, consider
potential costs, savings, payback and any secondary effects. While
some of the measures in Compressed Air Table 2 yield modest
potential savings as a percent of total facility energy use, the cost and
C02 savings can be significant because most air compressors are dri-
ven by electricity. When using the Wise Rules, remember that sev-
eral of the measures may overlap or complement each other and
energy savings rates may not be additive. In addition, Wise Rules for
similar measures are addressed from different perspectives. Some are
stated in terms of the air compressor's energy use, others in terms of
a facility's total energy use, or as a function of a physical parameter
(e.g., change in energy use with a change in pressure).
Compressed Air Notes
Talbott, E.M., Compressed Air Systems: A Guidebook on Energy and
Cost Savings, 2nd Edition, Fairmont Press, 1992, p. 160.
2 Oregon State University, AIRMaster Compressed Air System
Audit and Analysis Software, How to Take a Self-Guided Tour of
Your Compressed Air System," 1996 revised in 1997, p. 2. (Self-
Guided Tour)
3 DOE/IAC Industrial Assessment Database, July 1997.
Rutgers University, Office of Industrial Productivity & Energy Assessment
(OIPEA), Modem Industrial Assessments: A Training Manual, Version I.Ob,
1995, p. 6-28.
' Oregon State University, Self-Guided Tour, p. 5.
6 Rutgers, p. 6-28.
7 DOE/IAC Database.
Oregon State University, AIRMaster Compressed Air System Audit and
Analysis Software Version 1.4, Analysis Methodology Manual for AIRMaster,"
1996 revised in 1997, p. 32.
^ Oregon State University, AIRMaster Compressed Air System Audit and
Analysis Software, Case Studies: Compressed Air System Audits Using
AIRMaster," 1996 revised in 1997 pp. 20-21.
Oregon State University, AIRMaster Case Studies, p. 12.
11 DOE/IAC Database.
12 Rutgers, p. 6-17.
13 Rutgers, p. 6-17.
14 DOE/IAC Database.
1' Oregon State University, Self-Guided Tour, p. 8.
16 DOE/IAC Database.
17 Talbott, E.M., p. 112.
1° Oregon State University, Self-Guided Tour, p. 8.
^ Oregon State University, Self-Guided Tour, p. 8.
20 DOE/IAC Database.
2^ ICF Kaiser Consulting Group estimate based on Talbott, p. 77; 3M,
"Compressed Air Optimization," 1994, p. 9.
Bonneville Power Administration, Industrial Compressed Air System Enern
i J Of
Efficiency Guidebook, 1996, p. 2-2 and p. 4-5.
23 Talbott, p. 93.
24
Rutgers, p. 6-22.
25 Talbott, p. 91.
26 Rutgers, p. 6-16.
27 DOE/IAC Database.
2° Oregon State University, Self-Guided Tour, p. 9.
° 3M, "Compressed Air Optimization," 1994, p. 9.
30 3M, p. 9.
6. Compressed Air Systems
Wise Rules
Page 25
-------
Compressed Air Table 2: Summary of Compressed Air Efficiency Measures
Source
Average Energy Savings*
Rulel
Rule 2
Rule 4
RuleS
Rule 6
Rule?
RuleS
RuleS
Rule 10
Rule 11
Rule 12
Table 1
Rule 13
Rule 14
Rule 15
Measure
(IAC recommendation rate)
All Efficiency Improvements
Implement typical efficiency improvements, 20% to 50%
which may include many or all of the
measures below
Implement typical efficiency improvements, 0.4% of total facility energy use
which may include many or all of the
measures below (68%)
1% per 5°F reduction
0.2% of total facility energy use
Use Cooler Outside Air
Use cooler air for intakes
Use cooler air for intakes (37%)
Optimize Load
Install or adjust unloading controls
Upgrade screw compressor controls (1%)
Reduce Compressor Air Pressure
Reduce compressor pressure (15%)
Reduce compressor pressure
Eliminate /Reduce Compressed Air Use
Eliminate/reduce some uses of air (5%) 0.6% of total facility energy use
10%
0.8% of total facility energy use
0.4% of total facility energy use
1% per 2 psi reduction**
Eliminate Air Leaks
Repair air leaks
Repair air leaks (36%)
Reduce air leaks in distribution system
Repair 1/16" leak
30% or more
0.4% of total facility energy use
0.7% decrease in compressor
energy use per 1 psi loss
reduction**
7,560 kWh per leak per yr
Recover Waste Heat
Recover waste heat from compressors (8%) 1.8% of total facility energy use
Change Filters and Clean Coolers
Change dryer filters at 8 to 10 psi drop
Clean intercoolers to reduce
compressor working temperature
Average Annual Cost Savings
(payback)
$4,300 (5 months)
less than 2 years
$1,400 (5 months)
$7,900 (10 months)
$2,800 (4 months)
$7,300 (6 months)
$3,900 (3 months)
$360/yr
$2,700 (10 months)
0.5% per avoided 1 psi drop in pressure
1% per 1PF reduction
Source references for each Wise Rule are included in the chapter notes.
* Percent of compressed air system energy use, unless noted.
** Based on compressed air system pressure of approximately 100 psi.
Page 26
Wise Rules
6. Compressed Air Systems
-------
7. PROCESS Cow
Introduction
Many manufacturing processes require that materials or com-
ponents be cooled to lower temperatures. Chillers, heat
pumps and other refrigeration equipment used as heat sinks for a
variety of industrial processes. Efficiency measures for process
cooling include using cooling tower water in place of refrigeration
or chilling, modifying the refrigeration system to operate at a lower
pressure, increasing chilled water temperatures, and using variable
speed drives (VSDs).
Process Cooling Figure 1 illustrates the potential energy savings
from process cooling efficiency measures based on specific recom-
mendations in the DOE/IAC database. Process cooling measures
were recommended during six percent of the IAC audits with esti-
mated savings of about one percent of a facility's total energy use
and a simple payback of 20 months. Cooling tower measures were
recommended at three percent of audited facilities, with estimated
energy savings of almost one percent and a 14 month simple pay-
back. Process Cooling Table 2, at the end of this chapter, sum-
marizes the Wise Rules presented in this chapter, along with cost
savings estimates, where available.
Process Cooling Figure 1
Energy Savings from Process Cooling Efficiency Measures*
Energy Efficient Chillers and
Refrigeration Units
There are several energy efficiency options available when
installing new chilling equipment. For example, oversizing con-
denser water supply pipes can reduce head pressure and pumping
requirements. Evaporative cooled chillers consume considerably
less energy per ton of cooling capacity then water- and air-cooled
chillers. Using high efficiency compressors can also reduce chiller
energy use.
Process Cooling Wise Rule 1
Installing energy efficient chillers and refrigeration
systems can save about 1% of a. facility's total energy
use with an average simple payback of 23 months.1
Recommendation Rate
0% 1%
Process Cooling
(20 month payback)
Cooling Tower Measures
(14 month payback)
Chillers and Refrigeration
(23 month payback)
Recommendation Rate
Energy Savings
0.2% 0.4% 0.6% 0.8%
Energy Savings Rate (percent of total facility energy use)
1.2%
* Results from the DOE/IAC Database (1/90-7/97). The IAC data reflect average potential impacts from energy efficiency measures at small-to-medium sized manufacturing
facilities across all sectors and regions of the country. Most IAC audit recommendations are expected to be implemented within two years and typically have a one-to-two year
payback period. (See Chapter 1.)
7. Process Cooling
Wise Rules
Page 27
-------
Cooling Tower Water
Using cooling tower water in place of a chiller can dramatically
reduce cooling energy use when the outside temperature is low
enough to achieve the required process temperature. This
method of cooling is referred as "free cooling" because the chiller
is not used.
Process Cooling Wise Rule 2
"Free cooling" with cooling tower water can reduce a
facility's total energy use by about 1% with an average
simple payback of 14 months.2
Process Cooling Wise Rule 3
Free cooling can reduce cooling system energy use by as
much as 40% depending on location and load profile.3
Refrigeration and Chillers
Reducing the cooling load is a direct approach to cutting chiller
energy use. A cooling system audit may identify opportunities for
improving insulation and eliminating unnecessary heat sources.
Raising the chilled water set temperature can also reduce chiller
energy use. By monitoring the minimum requirements on the
chilled water temperature, the chiller can be reset appropriately to
meet the demands of the system without wasting energy.
Refrigerant subcooling decreases the load on the compressor and
reduces chiller energy use. Oversizing or continuous operation of
Procees Cooling Table 1
Energy Savings from Increasing Chilled Water
Temperature5
Chiller Type
Screw Compressor
Energy Savings
(Energy Savings per 1°F Increase in Temperature)
2.5%
Centrifugal Compressor
1.7%
Reciprocating Compressor
1.2%
cooling towers can lower condenser cooling water temperature and
reduce cooling system energy use. Careful system maintenance
and removal of non-condensable fluids can lower operating pres-
sure and save energy.
Process Cooling Wise Rule k
Increasing chilled water temperature by 1°F reduces
chiller energy use by 0.6% to 2.5%.4 (See Process
Cooling Table 1 for data on specific chiller types.)
Process Cooling Wise Rule 5
Reducing condenser pressure by 10 psi can decrease
refrigeration system energy use per ton of refrigeration
(kW/ton) by about 6%.6
Process Cooling Wise Rule 6
For each 1°F decrease in condenser cooling water
temperature, until optimal water temperature is
reached, there is a decrease in chiller energy use by up
to 3.5%.7
Freezing
The freezing process in a manufacturing facility can be made more
efficient by reducing heat loss through the use of improved insu-
lation (such as air locks) and by freezing products in batches rather
than continuously.
Process Cooling Wise Rule 7
Eliminating heat losses from leaks and improper
defrosting can reduce refrigeration system energy use by
10% to 20%.8
Process Cooling Wise Rule 8
Freezing products in batches rather than continuously
can reduce freezing process energy use by up to 20%.9
Absorption Chiller
0.6%
Page 28
Wise Rules
7. Process Cooling
-------
Variable Speed Drives
The application of variable speed drives (VSD) can reduce energy
use when cooling loads vary over time. VSDs can be applied to the
compressor within the chiller or, in some situations, utilized in
chilled water distribution.
Process Cooling Wise Rule 9
Installing variable speed drives in place of constant
speed systems can reduce cooling system energy use
by 30% to 50%, depending on load profile.10
Summary of Wise Rules for
Process Cooling Systems
Process Cooling Table 2 (next page) summarizes Process Cooling
Wise Rules contained in this chapter. These Wise Rules can be
used to identify and estimate potential energy saving from boiler
efficiency measures. When evaluating options, consider potential
costs, savings, payback times, and any secondary impacts. When
using the Wise Rules, remember that several of the measures may
overlap or complement each other and energy savings rates may
not be additive. In addition, multiple Wise Rules may express sav-
ings for similar measures from different perspectives: in terms of a
facility's total energy use, an end-use's or process' energy use, or as
a function of a physical parameter such as temperature.
Process Cooling Notes
1 DOE/IAC Industrial Assessment Database, July 1997.
2 DOE/IAC Database.
^ ICF Kaiser Consulting Group estimate based on D. Murphy, "Cooling
Towers Used for Free Cooling," ASHRAEJournal, June 1991, pp. 16-26.
Clevenger, L. and J. Hassel, "Case Study: From Jump Start to High Gear -
How DuPont is Cutting Costs by Boosting Energy Efficiency," Pollution
Prevention Review, Summer 1994, p. 304.
' Clevenger and Hassel, p. 304.
° Bonneville Power Administration (BPA), Washington State Energy Office,
Electric Ideas Clearinghouse, "Improving Industrial Refrigeration Energy
Efficiency," October 1991, p. 3.
' Bonneville Power Administration (BPA), Washington State Energy Office,
Electric Ideas Clearinghouse, "Optimizing Cooling Tower Performance,"
November 1991, p. 1.
° Centre for the Analysis and Dissemination of Demonstrated Energy
Technologies (CADDET), Newsletter No. 4 December 1996, p. 16.
9 CADDET, p. 16.
York International, "HVAC&R Engineering Update: Examining Part-Load
Performance Gives You the Full Story on Chiller Efficiency," 1994.
7. Process Cooling
Wise Rules
-------
Process Cooling Table 2: Summary of Process Cooling Efficiency Measures
Source Measure
(IAC recommendation rale)
Average Energy Savings
Average Annual Cost Savings
and (Payback)
Rulel
Rule 2
RuleS
Rule 4
RuleS
Rule 6
Rule?
RuleS
RuleS
Implement typical efficiency improvements,
which may include many or all of
the measures below (6%)
Install energy efficient chillers and
refrigeration units (3%)
Cooling Towers
Use cooling tower to replace
chiller for free cooling (3%)
Use free cooling
Refrigeration and Chillers
Increase chilled water temperature
Reduce condenser pressure
Decrease condenser working temperature
1.1 % of total facility energy use
1.2% of total facility energy use
$11,200 (20 months)
$11,200 (23 months)
0.8% of total facility energy use $11,000 (14 months)
up to 40% of cooling system energy
0.6% to 2.5% reduction in energy
input per 1°F increase
6% decrease in refrigeration energy
use per ton for each 10 psi reduction
3.5% reduction in chiller energy
for each 1 F decrease
Freezing
Reduce heat loss and improper defrosting
Use continuous freezing
Install variable speed drives
10% to 20% decrease in freezer
energy use
20% decrease in freezer energy use
30% to 50% reduction in cooling
energy use
Source references for each Wise Rule are included in the chapter notes.
Page 30
Wise Rules
7. Process Cooling
-------
In this appendix, we present examples of sector-specific savings
from the DOE IAC database. The IAC audit database contains
information on the expected impacts from energy efficiency
measures recommended at small-to-medium sized manufactur-
ing facilities. IAC audits typically recommend measures with
short (one to two year) payback periods. The energy and cost
savings represent averages across industry groups, years, and
regions.
"Average percent energy savings" are defined as the average
reduction in a facility's total energy use resulting from the imple-
mentation of a specific recommendation. For example, a typical
facility in the food industry (SIC 20) could expect to save about
six percent of their total facility energy use by implementing the
measures recommended during an LAC audit (refer to Table A-2).
The average simple payback period is defined as the amount of
time it takes to recover initial investment costs through energy
savings.
Table A-l provides the definition of the Standard Industrial
Classification (SIC) codes for manufacturing industries.
Table A-1:
SIC Code
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
SIC Code Definitions
Classification
Food and Kindred Products
Tobacco*
Textile Mill Products
Apparel and Other Textile Products
Lumber and Wood Products
Furniture and Fixtures
Paper and Allied Products
Printing and Publishing
Chemicals and Allied Products
Petroleum and Coal Products
Rubber and Misc. Plastics Products
Leather and Leather Products
Stone, Clay and Glass Products
Primary Metal Industries
Fabricated Metal Industries
Industrial Machinery and Equipment
Electronic and Other Electric Equipment
Transportation Equipment
Instruments and Related Products
Misc. Manufacturing Industries
*Only three IAC audits were conducted for SIC 21 (1/91-7/97).
Appendix A
Wise Rules
Page 31
-------
Table A-2: Average Impacts of All Energy Efficiency Measures Recommended by IAC Audits, by Sector'
SIC Code & Manufacturing
Classification
Average Annual Average Annual Average Average Annual Average
Energy Savings Energy Savings Implementation Cost Savings Simple
(% of total facility (MMBtu) COSt (dollars) Payback
energy use) (dollars) (months)
20 Food and Kindred Products
21 Tobacco**
22 Textile Mill Products
23 Apparel and Other Textile Products
24 Lumber and Wood Products
25 Furniture and Fixtures
20 Paper and Allied Products
27 Printing and Publishing
28 Chemicals and Allied Products
20 Petroleum and Coal Products
30 Rubber and Misc. Plastics Products
31 Leather and Leather Products
32 Stone, Clay and Glass Products
33 Primary Metal Industries
34 Fabricated Metal Industries
35 Industrial Machinery and Equipment
30 Electronic and Other Electric Equipment
37 Transportation Equipment
38 Instruments and Related Products
30 Misc. Manufacturing Industries
6.2%
4.4%
6.8%
8.8%
4.7%
12.3%
8.5%
7.1%
5.7%
13.4%
4.2%
4.0%
5.2%
7.0%
7.2%
5.9%
8.5%
7.3%
8.8%
9.7%
4,400
8,800
8,300
1,700
7,600
3,700
7,900
1,800
6,200
16,400
2,500
1,300
16,800
5,700
2,900
2,200
3,200
2,600
2,300
2,300
78,000
85,000
103,000
22,000
86,000
47,000
65,000
42,000
66,000
189,000
43,000
25,000
183,000
57,000
33,000
31,000
51,000
38,000
41,000
30,000
41,000
52,000
64,000
21,000
56,000
29,000
51,000
26,000
37,000
80,000
35,000
18,000
98,000
46,000
27,000
25,000
39,000
30,000
32,000
24,000
23
19
19
13
19
20
15
20
21
28
15
16
22
15
14
15
16
15
15
15
* Based on DOE/IAC estimates at audits of 4,300 manufacturing companies (1/90-7/97). Savings may not be additive.
** Only three IAC audits were conducted for Tobacco companies (SIC 21).
Page 32
Wise Rules
Appendix A
-------
Table A-3: Food and Kindred Products Sector*(SIC 20)
Measure
Recommendation
Rate
Average Annual
Energy Savings
(% of total facility
energy use)
Average Annual
Energy Savings
Average
Implementation
Cost
(dollars)
Average
Annual Cost
Savings
(dollars)
Average
Simple
Payback
(months)
Miscellaneous Heat
Recovery
Steam Operations
degeneration**
Boiler Hardware
Other Process Waste
Heat Recovery
Heat Recovery
mtt
irom equipment
Chillers and
Refrigeration
Flue Gas Recuperation
Boiler Maintenance
Steam Condensate
Thermal System
Insulation
Steam Leaks and
Insulation
Motor Hardware
Air Compressor
Operations
Lighting Hardware
1%
2%
5%
3%
7%
15%
12%
8%
36%
9%
23%
20%
62%
35%
75%
21.2%
8.2%
5.5%
5.5%
5.2%
4.5%
3.2%
2.9%
2.3%
2.3%
2.2%
0.9%
0.6%
0.5%
0.4%
18,500
4,800
7,100
2,000
3,700
2,700
1,900
2,300
2,000
1,300
1,700
900
470
300
250
144,300
400
705,900
15,200
19,600
15,600
26,300
11,700
1,200
3,100
4,200
1,600
11,300
1,400
5,800
54,800
11,400
229,000
7,600
13,600
10,000
15,200
7,100
5,600
6,900
3,400
3,200
6,300
3,600
4,200
32
0
37
24
17
19
21
20
3
5
15
6
22
5
17
* Calculations based on IAC estimates at audits of 527 companies in SIC 20 (1/90 - 7/97). Savings may not be additive.
** Cogeneration energy savings are based on primary fuel savings from electricity generation, including fuel inputs at off-site powerplants for purchased electricity.
Appendix A
Wise Rules
-------
Table A-4: Textile Mill Products*(SIC 22)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Cogeneration**
Steam Operations
Heat Recovery from
Equipment
Other Process Waste
Heat Recovery
Roller Hardware
Steam Condensate
Flue Gas Recuperation
Roller Maintenance
Thermal System
Insulation
Steam Leaks and
Insulation
Lighting Hardware
Motor Hardware
Air Compressor Operations
Air Compressor Hardware
Motor Operations
3%
2%
10%
13%
5%
10%
13%
27%
26%
22%
77%
64%
49%
36%
49%
16.0%
7.7%
5.6%
4.1%
3.4%
2.6%
2.2%
1.8%
1.3%
0.8%
0.7%
0.5%
0.5%
0.5%
0.4%
9,700
15,400
4,700
5,500
6,000
4,200
4,900
2,500
1,200
1,300
850
700
600
500
600
211,000
9,000
11,000
22,000
60,000
16,000
19,000
15,000
4,000
1,000
38,000
26,700
3,000
2,000
11,000
111,000
42,000
15,000
19,000
21,000
14,000
14,000
13,000
5,000
4,000
13,000
9,200
7,000
5,000
7,000
23
3
9
14
34
13
16
14
10
4
35
34
5
5
18
* Calculations based on IAC estimates at audits of 144 companies in SIC 22 (1/90 - 7/97). Savings may not be additive.
** Cogeneration energy savings are based on primary fuel savings from electricity generation, including fuel inputs at off-site powerplants for purchased electricity.
Page 34
Wise Rules
Appendix A
-------
Table A-5: Apparel and Other Textile Products* (SIC 23)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Miscellaneous Cooling
Space Conditioning
Controls
Flue Gas Recuperation
Building Envelope
Infiltration
Air Circulation Hardware
Space Conditioning
Operation
Other Process Waste
Heat Recovery
Heat Recovery from
Equipment
Ughting Operation
Thermal System
Insulation
Ughting Hardware
Steam Leaks and
Insulation
Boiler Maintenance
Motor Hardware
Air Compressor
Operations
1%
19%
4%
4%
12%
15%
5%
19%
21%
15%
81%
16%
21%
35%
51%
46.2%
8.3%
6.7%
5.3%
4.9%
4.3%
3.5%
3.0%
2.9%
2.7%
1.7%
1.6%
1.2%
0.7%
0.5%
4,000
600
650
450
750
700
350
350
400
1,700
300
600
400
150
100
240,000
2,200
5,600
1,200
4,200
3,200
1,700
2,000
8,200
3,600
10,300
950
1,300
6,700
350
84,600
4,500
3,300
2,500
10,300
8,600
2,100
1,400
7,600
6,800
5,800
1,700
2,000
2,500
1,600
34
6
20
6
5
4
9
17
13
6
21
7
7
33
2
* Calculations based on IAC estimates at audits of 113 companies in SIC 23 (1/90 - 7/97). Savings may not be additive.
Appendix A
Wise Rules
Page 35
-------
Table A-6: Lumber and Wood Products* (SIC 24)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Air Circulation
Hardware
Heating/Cooling
Hardware
Boiler Maintenance
Boiler Operation
degeneration**
Heat Becovery
from Equipment
Steam Leaks and
Insulation
Space Conditioning
Controls
Thermal System
Insulation
Air Compressor
Operations
Motor Hardware
Motor Operations
1%
4%
14%
3%
6%
10%
11%
7%
9%
63%
74%
55%
11.0%
8.0%
7.0%
4.8%
4.6%
2.0%
1.7%
1.4%
0.8%
0.3%
0.2%
0.2%
1,000
800
13,100
27,700
41,700
700
4,800
350
1,900
650
450
250
11,900
6,600
2,900
9,700
680,000
8,100
3,000
1,000
4,600
5,800
17,000
7,100
4,800
5,100
18,100
19,800
297,000
2,700
5,800
2,600
3,300
8,400
7,000
3,700
30
15
2
6
27
36
6
5
17
8
29
23
* Calculations based on IAC estimates at audits of 213 companies in SIC 24 (1/90 - 7/97). Savings may not be additive.
** Cogeneration energy savings are based on primary fuel savings from electricity generation, including fuel inputs at off-site powerplants for purchased electricity.
Page 36
Wise Rules
Appendix A
-------
Table A-7: Furniture and Fixtures* (SIC 25)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Cogeneration**
Boiler Hardware
General Ventilation
Other Process
Waste Heat Recovery
Heat Recovery
from Equipment
Thermal System
Insulation
Space Conditioning
Operation
Space Conditioning
Controls
Boiler Maintenance
Building Envelope
Infiltration
Air Circulation
Hardware
Equipment Use
Reduction
Lighting Hardware
Air Compressor
Operations
Motor Hardware
5%
2%
8%
5%
21%
11%
16%
11%
9%
15%
10%
18%
77%
60%
50%
17.4%
14.1%
7.7%
7.7%
6.4%
5.8%
3.8%
3.8%
3.4%
2.9%
2.8%
2.1%
1.0%
0.7%
0.5%
17,400
15,600
3,000
3,400
1,800
2,500
700
500
800
750
550
500
200
250
150
402,900
2,300
19,800
11,700
4,700
14,000
4,100
2,100
1,000
5,400
6,500
450
7,500
950
7,000
117,000
38,700
10,800
12,500
6,200
7,400
5,000
3,100
1,500
2,800
3,500
4,400
4,500
3,400
3,800
41
1
22
11
9
23
10
8
9
23
22
1
20
3
22
* Calculations based on IAC estimates at audits of 109 companies in SIC 25 (1/90 - 7/97). Savings may not be additive.
** Cogeneration energy savings are based on primary fuel savings from electricity generation, including fuel inputs at off-site powerplants for purchased electricity.
Appendix A
Wise Rules
Page 37
-------
Table A-8: Paper and Allied Products* (SIC 26)
Measure
Recommendation
Rate
Average Annual
Energy Savings
(% of total facility
energy use)
Average Annual
Energy Savings
Average
Implementation
Cost
(dollars)
Average
Annual Cost
Savings
(dollars)
Average
Simple
Payback
(months)
Mechanical System
Design
Hue Gas-Other Uses
Degeneration**
Other Process Waste
Heat Recovery
Steam Trap Management
Heating/Cooling
Hardware
Miscellaneous Building
Envelope
Boiler Operation
Building Envelope
Infiltration
Heat Becovery
from Equipment
Space Conditioning
Controls
Boiler Maintenance
Ughting Hardware
Air Compressor
Operations
Motor Hardware
1%
2%
4%
6%
3%
4%
4%
7%
12%
15%
10%
25%
78%
39%
61%
43.1%
19.2%
11.0%
7.5%
7.0%
4.7%
4.6%
2.9%
2.5%
1.9%
1.9%
1.2%
0.5%
0.5%
0.4%
62,500
33,700
29,500
15,900
4,400
1,200
2,400
2,300
1,100
2,500
850
1,900
350
300
450
219,400
69,800
400,100
72,700
2,300
35,200
19,700
3,000
13,900
10,300
2,500
4,200
9,700
1,100
14,600
161,000
98,200
275,900
39,200
21,000
9,900
6,500
8,200
4,300
7,600
4,300
6,100
6,900
4,600
8,200
16
9
17
22
1
43
36
4
39
16
7
8
17
3
21
* Calculations based on IAC estimates at audits of 226 companies in SIC 26 (1/90 - 7/97). Savings may not be additive.
** Cogeneration energy savings are based on primary fuel savings from electricity generation, including fuel inputs at off-site powerplants for purchased electricity.
Page 38
Wise Rules
Appendix A
-------
Table A-9: Printing and Publishing* (SIC 27)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Heating/Cooling Hardware
Flue Gas Recuperation
Space Conditioning
Controls
Heat Recovery from
Equipment
Roller Hardware
Air Circulation
Hardware
Miscellaneous Ruilding
Envelope
Space Conditioning
Operation
Equipment Use
Reduction
Motor Hardware
lighting Hardware
Ruilding Envelope
Infiltration
Air Compressor
Motor Operations
Ughting Controls
7%
3%
19%
16%
4%
7%
10%
25%
12%
42%
79%
15%
45%
31%
31%
5.6%
4.2%
4.0%
3.5%
3.2%
2.9%
2.4%
2.2%
1.7%
1.3%
1.0%
1.0%
0.8%
0.5%
0.4%
450
2,000
850
1,000
800
400
800
300
600
300
300
250
250
150
120
26,700
15,600
4,100
5,600
12,200
4,900
16,000
3,000
46,100
6,900
9,200
1,100
1,000
2,700
1,200
9,600
8,300
4,500
5,200
4,300
2,300
5,000
2,900
4,700
5,400
5,400
1,300
4,000
2,300
1,700
33
23
11
13
34
25
37
13
118
15
20
11
3
14
9
* Calculations based on IAC estimates at audits of 182 companies in SIC 27 (1/90 - 7/97). Savings may not be additive.
Appendix A
Wise Rules
-------
Table A-10: Chemicals and Allied Products* (SIC 28)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Cogeneration**
General Ventilation
Boiler Hardware
Flue Gas Recuperation
Heating/Cooling
Hardware
Other Process Waste
Heat Recovery
Boiler Maintenance
Space Conditioning
Operation
Heat Recovery from
Equipment
Steam Leaks and
Insulation
Equipment Use
Reduction
Air Compressor
Operations
Motor Hardware
Lighting Hardware
Motor Operations
4%
1%
1%
9%
5%
7%
23%
9%
10%
17%
12%
37%
62%
75%
34%
18.6%
9.9%
9.9%
5.1%
3.9%
2.7%
2.2%
2.2%
1.9%
1.6%
1.5%
0.8%
0.5%
0.3%
0.3%
11,400
900
20,500
8,000
1,900
7,400
2,500
800
1,200
4,600
950
400
450
200
500
772,000
1,500
125,000
27,900
56,300
13,000
1,200
2,400
4,400
2,300
1,500
450
15,000
7,200
1,700
147,900
3,700
73,900
22,200
19,600
21,000
6,800
8,400
4,800
8,800
4,400
5,400
6,000
4,200
2,700
63
5
20
15
34
8
2
3
11
3
4
1
30
21
8
* Calculations based on IAC estimates at audits of 191 companies in SIC 28 (1/90 - 7/97). Savings may not be additive.
** Cogeneration energy savings are based on primary fuel savings from electricity generation, including fuel inputs at off-site powerplants for purchased electricity.
Page 40
Wise Rules
Appendix A
-------
Table A-11: Petroleum and Coal Products* (SIC 29)
Measure
Recommendation
Rate
Average Annual
Energy Savings
(% of total facility
energy use)
Average Annual
Energy Savings
Average
Implementation
Cost
(dollars)
Average
Annual Cost
Savings
(dollars)
Average
Simple
Payback
(months)
Cogeneration**
Furnace Operations
Other Equipment
Hardware
Furnace Hardware
Space Conditioning
Controls
Flue Gas Recuperation
Boiler Hardware
Hue Gas-Other Uses
Heat Recovery from
Equipment
Thermal System
Insulation
Steam Trap
Management
Boiler Operation
Boiler Maintenance
Furnace Maintenance
Steam Leaks and
Insulation
3%
3%
3%
3%
3%
15%
6%
6%
6%
65%
6%
12%
21%
12%
32%
23.6%
19.6%
10.1%
8.8%
8.1%
7.8%
7.4%
5.3%
3.8%
3.7%
3.6%
3.0%
2.5%
1.7%
0.9%
262,200
9,500
16,000
950
2,000
9,200
2,300
8,700
15,300
3,900
3,300
2,300
2,900
600
1,200
4,815,000
4,000
47,900
0
400
40,900
11,000
12,000
117,900
8,100
4,700
6,700
3,300
750
1,400
1,247,700
23,700
46,000
3,800
7,000
36,100
6,400
30,900
44,400
18,400
9,500
7,500
9,500
1,600
6,200
46
2
13
0
1
14
21
5
32
5
6
11
4
6
3
* Calculations based on IAC estimates at audits of 34 companies in SIC 29 (1/90 - 7/97). Savings may not be additive.
** Cogeneration energy savings are based on primary fuel savings from electricity generation, including fuel inputs at off-site powerplants for purchased electricity.
Appendix A
Wise Rules
Page 41
-------
Table A-12: Rubber and Misc. Plastics Products* (SIC 30)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Flue Gas Recuperation
Other Process Waste
Heat Recovery
Other Equipment
Hardware
Heating/Cooling
Hardware
Roiler Maintenance
Heat Recovery
from Equipment
Equipment Use
Reduction
Space Conditioning
Operation
Equipment Automation
Air Circulation Hardware
Space Conditioning
Controls
Thermal System
Insulation
Ughting Hardware
Motor Hardware
Air Compressor
Operations
4%
3%
7%
7%
11%
10%
13%
10%
13%
10%
12%
33%
74%
59%
42%
8.3%
5.0%
2.4%
2.3%
2.2%
2.2%
2.1%
2.0%
1.7%
1.7%
1.6%
0.8%
0.5%
0.5%
0.4%
8,000
2,300
650
800
1,700
1,100
650
800
450
650
500
500
300
400
250
19,800
24,200
20,100
20,300
3,000
5,100
2,600
3,100
2,800
6,900
1,300
3,000
7,200
15,200
1,300
20,600
11.600
11,300
9,200
6,300
4,900
8,200
5,800
7,400
4,300
3,700
6,300
5,100
6,800
4,500
12
25
21
26
6
12
4
6
5
19
4
6
17
27
3
* Calculations based on IAC estimates at audits of 440 companies in SIC 30 (1/90 - 7/97). Savings may not be additive.
Page 42
Wise Rules
Appendix A
-------
Table A-13: Leather and Leather Products* (SIC 31)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Thermal System
Infiltration
Steam Maintenance
Steam Trap Management
Heating/Cooling
Hardware
Space Conditioning
Operation
Lighting Level
Steam Leaks and
Insulation
Boiler Maintenance
Heat Recovery from
Equipment
Lighting Hardware
Lighting Controls
Thermal System
Insulation
Air Compressor
Operations
Air Compressor
Hardware
Motor Hardware
6%
3%
6%
9%
15%
12%
21%
21%
21%
61%
18%
27%
52%
58%
39%
7.3%
5.9%
5.7%
5.3%
3.8%
2.3%
1.8%
1.8%
1.4%
0.9%
0.7%
0.6%
0.5%
0.3%
0.3%
750
700
1,400
100
500
250
1,200
1,100
100
300
200
300
200
70
200
2,100
200
1,700
19,100
5,300
700
1,600
2,500
450
18,100
1,000
2,500
850
600
7,700
4,800
2,400
4,500
3,000
2,500
3,400
4,100
3,400
900
7,700
1,700
1,600
4,300
1,400
5,000
5
1
5
77
25
2
5
9
6
28
7
19
2
5
18
* Calculations based on IAC estimates at audits of 33 companies in SIC 31 (1/90 - 7/97). Savings may not be additive.
Appendix A
Wise Rules
-------
Table A-14: Stone, Clay and Glass Products* (SIC 32)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Miscellaneous Heat
Recovery
Thermal System
Isolation
degeneration**
General Operations
Maintenance
Hue Gas-Other Uses
Flue Gas Recuperation
Thermal System
Insulation
Heat Recovery
from Equipment
Roller Maintenance
Other Equipment
Hardware
Other Process Waste
Heat Recovery
Building Envelope
Infiltration
Roller Operation
Motor Hardware
Air Compr essor
Operations
1%
1%
7%
1%
6%
9%
22%
12%
11%
9%
6%
8%
4%
70%
56%
38.8%
23.7%
10.2%
5.3%
4.2%
4.1%
2.4%
2.3%
2.2%
2.2%
2.2%
1.4%
1.4%
0.3%
0.3%
7,400
600
123,800
1,000
27,700
14,800
5,000
3,600
2,300
5,000
6,300
4,700
2,600
1,100
850
32,300
6,000
1,447,400
6,000
46,100
54,300
7,200
5,100
1,000
153,800
23,500
1,800
3,400
30,800
3,200
36,900
3,800
464,000
4,600
65,800
33,400
15,500
10,200
8,900
89,700
19,000
10,600
7,600
15,000
9,800
11
19
37
15
8
19
6
6
1
21
15
2
5
25
4
* Calculations based on IAC estimates at audits of 151 companies in SIC 32 (1/90 - 7/97). Savings may not be additive.
** Cogeneration energy savings are based on primary fuel savings from electricity generation, including fuel inputs at off-site powerplants for purchased electricity.
Page 44
Wise Rules
Appendix A
-------
Table A-15: Primary Metal Industries* (SIC 33)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Cogeneration**
Boiler Operation
Furnace Operations
Space Conditioning
Operation
Hue Gas-Other Uses
Furnace Maintenance
Flue Gas Recuperation
Building Envelope
Infiltration
Heat Recovery from
Equipment
Boiler Maintenance
Thermal System
Insulation
Equipment Use
Reduction
Motor Hardware
Air Compressor
Operations
Ughting Hardware
2%
4%
3%
4%
8%
3%
14%
6%
12%
10%
24%
11%
62%
45%
70%
12.1%
7.0%
6.9%
6.8%
6.2%
6.2%
5.9%
3.7%
2.8%
2.0%
1.7%
1.7%
0.6%
0.6%
0.3%
8,100
6,300
11,500
3,300
10,700
4,100
6,000
1,600
1,600
1,400
1,400
2,000
500
450
250
473,600
13,000
2,900
18,700
106,400
7,200
20,600
10,600
8,500
1,600
2,500
1,100
11,000
2,300
6,000
112,000
18,100
26,400
8,900
52,400
15,700
17,800
6,200
6,800
5,500
6,400
7,600
7,000
6,600
3,800
51
9
1
25
24
6
14
21
15
3
5
2
20
4
19
* Calculations based on IAC estimates at audits of 263 companies in SIC 33 (1/90 - 7/97). Savings may not be additive.
** Cogeneration energy savings are based on primary fuel savings from electricity generation, including fuel inputs at off-site powerplants for purchased electricity.
Appendix A
Wise Rules
Page 45
-------
Table A-16: Fabricated Metal Industries* (SIC 34)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Cogeneration**
Flue Gas-Other Uses
Heating/Cooling
Hardware
Flue Gas Recuperation
Air Circulation
Hardware
Miscellaneous Building
Envelope
Heat Recovery from
Equipment
Boiler Maintenance
Space Conditioning
Operation
Building Envelope
Infiltration
Thermal System
Insulation
Space Conditioning
Controls
Air Compressor
Operations
Lighting Hardware
Motor Hardware
2%
4%
7%
5%
8%
7%
16%
12%
9%
15%
21%
14%
55%
75%
54%
15.2%
8.2%
4.5%
4.1%
2.6%
2.6%
2.5%
2.5%
2.1%
2.0%
1.8%
1.5%
0.6%
0.5%
0.5%
13,000
6,800
950
4,200
800
1,100
900
1,500
700
700
800
600
250
200
200
323,000
19,300
20,100
20,700
5,400
17,100
3,700
1,400
1,500
2,800
3,800
1,500
890
6,700
6,600
121,000
21,400
5,300
11,000
4,500
5,400
3,800
4,600
3,800
3,000
3,800
3,500
4,300
4,800
3,900
32
11
46
23
14
38
12
4
5
11
12
5
2
17
20
* Calculations based on IAC estimates at audits of 570 companies in SIC 34 (1/90 - 7/97). Savings may not be additive.
** Cogeneration energy savings are based on primary fuel savings from electricity generation, including fuel inputs at off-site powerplants for purchased electricity.
Page 46
Wise Rules
Appendix A
-------
Table A-17: Industrial Machinery and Equipment* (SIC 35)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Building Envelope
Infiltration
General Ventilation
Air Circulation Hardware
Space Conditioning
Operation
Heating/Cooling
Hardware
Space Conditioning
Controls
Miscellaneous Building
Envelope
Other Equipment
Hardware
Equipment Use
Beduction
Heat Becovery from
Equipment
Boiler Maintenance
Lighting Level
Lighting Hardware
Air Compressor
Operations
Motor Hardware
15%
7%
9%
15%
8%
13%
6%
7%
15%
21%
10%
12%
82%
55%
47%
4.3%
4.1%
4.0%
3.8%
3.8%
3.6%
3.2%
3.0%
2.8%
1.8%
1.7%
1.4%
0.7%
0.6%
0.6%
1,000
900
750
900
700
750
1,000
400
750
600
600
400
250
250
150
3,200
2,800
6,600
3,100
35,000
1,700
22,500
6,500
900
3,200
1,000
1,200
9,800
1,000
5,900
3,300
4,300
4,200
6,000
12,600
3,800
4,900
5,600
4,200
2,800
2,300
5,700
5,000
3,700
2,800
12
8
19
6
33
5
55
14
3
14
5
2
23
3
25
* Calculations based on IAC estimates at audits of 438 companies in SIC 35 (1/90 - 7/97). Savings may not be additive.
Appendix A
Wise Rules
Page 47
-------
Table A-18: Electronic and Other Electric Equipment* (SIC 36)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Humidity Control
degeneration**
Heating/Cooling
Hardware
Heat Recovery from
Equipment
Space Conditioning
Controls
Other Process Waste
Heat Recovery
Space Conditioning
Operation
Air Circulation
Hardware
Other Equipment
Hardware
Miscellaneous Ruilding
Envelope
Ruilding Envelope
Infiltration
Thermal System
Insulation
Lighting Hardware
Motor Hardware
Air Compressor
Operations
1%
1%
8%
20%
17%
5%
14%
8%
7%
6%
9%
20%
77%
55%
43%
31.2%
22.1%
6.2%
3.5%
3.4%
3.1%
2.9%
2.8%
2.6%
2.6%
2.4%
1.2%
1.1%
0.7%
0.6%
16,000
47,000
2,000
1,000
1,000
2,300
850
650
600
550
600
500
400
250
200
143,400
286,800
40,200
6,400
4,000
17,400
8,300
6,200
19,200
15,300
2,500
2,400
15,100
9,100
1,300
97,000
303,600
20,500
5,400
8,400
11,900
7,800
7,400
7,700
5,100
5,300
4,600
8,000
5,000
3,600
18
11
24
14
6
18
13
10
30
36
6
6
23
22
4
* Calculations based on IAC estimates at audits of 287 companies in SIC 36 (1/90 - 7/97). Savings may not be additive.
** Cogeneration energy savings are based on primary fuel savings from electricity generation, including fuel inputs at off-site powerplants for purchased electricity.
Page 48
Wise Rules
Appendix A
-------
Table A-19: Transportation Equipment* (SIC 37)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Flue Gas Recuperation
Miscellaneous Building
Envelope
Heating/Cooling
Hardware
Space Conditioning
Operation
Space Conditioning
Controls
Building Envelope
Infiltration
Heat Recovery from
AHt
tqui em
Boiler Maintenance
Equipment Automation
Ughting Level
Air Compressor
Operations
Lighting Hardware
Motor Hardware
Motor Operations
Air Compressor
Hardware
3%
5%
11%
12%
18%
9%
21%
9%
14%
15%
64%
79%
56%
31%
39%
8.4%
7.0%
5.8%
3.7%
2.8%
2.8%
2.7%
2.4%
1.8%
1.2%
1.0%
0.9%
0.8%
0.6%
0.4%
7,000
1,000
1,000
1,000
1,000
850
1,000
2,000
400
350
300
300
300
250
150
20,000
9,700
17,000
3,000
2,600
2,600
7,100
1,200
2,000
3,300
1,000
11,200
8,400
2,800
1,200
19,800
4,600
12,400
6,200
6,100
4,200
4,000
5,100
3,200
6,200
4,700
5,400
4,300
3,100
2,200
12
25
17
6
5
7
22
3
7
6
3
25
23
11
7
* Calculations based on IAC estimates at audits of 214 companies in SIC 37 (1/90 - 7/97). Savings may not be additive.
Appendix A
Wise Rules
-------
Table A-20: Instruments and Related Products* (SIC 38)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Solar Loading
Other Equipment
Hardware
Other Process Waste
Heat Recovery
Space Conditioning
Operation
Heat Recovery from
Equipment
General Ventilation
Equipment Use
Reduction
Heating/Cooling
Hardware
Lighting Hardware
Equipment Automation
Ruilding Envelope
Infiltration
Thermal System
Insulation
Motor Hardware
Air Compressor
Operations
Lighting Controls
2%
5%
5%
14%
13%
4%
14%
7%
83%
19%
13%
20%
57%
40%
34%
10.3%
9.3%
6.7%
5.3%
4.7%
4.6%
3.7%
2.6%
2.2%
2.1%
1.7%
1.1%
0.9%
0.7%
0.6%
550
1,000
4,000
600
1,000
900
700
450
450
400
450
350
250
100
150
4,900
60,600
13,400
3,100
5,200
8,000
600
40,400
18,900
2,900
1,500
1,700
9,400
350
1,700
4,100
26,600
19,000
7,800
5,600
4,700
4,400
12,400
10,300
3,900
5,100
2,400
4,400
2,100
2,400
14
27
8
5
11
20
2
39
22
9
3
5
25
2
8
* Calculations based on IAC estimates at audits of 95 companies in SIC 38 (1/90 - 7/97). Savings may not be additive.
Page 50
Wise Rules
Appendix A
-------
Table A-21: Misc. Manufacturing Industries* (SIC 39)
Measure
Recommendation Average Annual Average Annual Average Average Average
Rate Energy Savings Energy Savings Implementation Annual Cost Simple
(% of total facility (MMBtu) Cost Savings Payback
energy use) (dollars) (dollars) (months)
Alternate Fossil
Fuel Switching
Boiler Operation
degeneration**
Heating/Cooling
Hardware
Solar Loading
Heat Recovery from
AHt
tqui em
Flue Gas Recuperation
Boiler Maintenance
Miscellaneous Building
Envelope
Space Conditioning
Operation
Space Conditioning
Controls
Lighting Hardware
Air Compressor
Operations
Motor Hardware
Air Compressor
Hardware
1%
3%
1%
5%
4%
12%
5%
19%
8%
13%
13%
88%
48%
45%
41%
25.5%
24.0%
15.9%
10.3%
10.3%
7.0%
6.2%
5.6%
4.6%
3.9%
2.7%
1.0%
0.9%
0.7%
0.5%
2,000
7,000
8,000
1,000
700
2,000
4,000
1,000
800
600
1,000
250
150
100
100
21,700
15,100
165,000
58,400
13,900
4,800
8,200
1,200
19,000
1,700
2,800
8,000
950
4,300
800
29,000
5,900
54,000
14,100
4,400
11,500
12,300
4,400
6,000
3,000
7,800
4,600
3,100
2,200
1,100
9
31
37
50
38
5
8
3
38
7
4
21
4
24
9
* Calculations based on IAC estimates at audits of 75 companies in SIC 39 (1/90 - 7/97). Savings may not be additive.
** Cogeneration energy savings are based on primary fuel savings from electricity generation, including fuel inputs at off-site powerplants for purchased electricity.
Appendix A
Wise Rules
Page 51
-------
I
Table B-1: Helpful Conversion Factors
This appendix provides the necessary information to calculate
C02 emissions reductions from energy efficiency measures.
Once you have qualified project impacts (using Wise Rules,
metered data, and/or engineering estimates), simply multiply the
energy savings by the appropriate C02 emission coefficient. Use
Table B-2 to calculate C02 emission reductions from fuel sav-
ings and use Table B-3 to calculate C02 emissions reductions
from electricity savings. C02 emissions from electricity genera-
tion are a function of powerplant efficiency and fuel use. The
C02 emission coefficients in Table B-3 are average values that
reflect the mix of powerplants in each state. Feel free to use your
own site-specific information on fuel carbon content or pur-
chased electricity C02 emissions in place of the averages present-
ed here.
Example 1: Boiler Fuel Savings
Consider a boiler tune-up that is estimated to save 1,000
MMBtu of natural gas per year. Multiply the 1,000 MMBtu
savings by the C02 emission coefficient for natural gas, 117.08
pounds C02 per MMBtu (Table B-2) to calculate annual savings
of 117,080 pounds of C02. To express the greenhouse gas emis-
sions reduction in metric tons of carbon, multiply the pounds
of C02 saved by 1.237 x lO'4 (Table B-1) to yield 14.5 metric
tons of carbon.
Example 2: Air Compressor Electricity Savings
Consider a manufacturing facility in Florida that implements
compressed air system efficiency improvements that result in
annual savings of 100 MWh. Multiply the 100 MWh savings by
the C02 emission factor for electricity generated in Florida,
0.587 metric tons C02 per MWh (Table B-3), to calculate annu-
al savings of 58.7 metric tons of C02. To express the greenhouse
gas emissions reduction in metric tons of carbon, multiply the
metric tons of C02 saved by 0.2727 (Table B-1) to yield 16.0
metric tons of carbon.
To Convert
Tons
Tons
MMBtu
kWh
MWh
kWh
Quads
(quadrillion Btu)
Quads
(quadrillion Btu)
Therms
Horsepower (hp)
Btu
kWh
Carbon
(mass units)
Carbon Dioxide
(mass units)
Carbon
(metric tons)
Carbon Dioxide
(pounds)
To
Pounds
Metric Tons
Btu
Wh
kWh
Btu
Btu
kWh
Btu
kW
Joule (J)
Joule (J)
Carbon Dioxide
(mass units)
Carbon
(mass units)
Carbon Dioxide
(tons)
Carbon
(metric tons)
Multiply By
2000
0.9072
106
103
103
3413
1015
2.93 x 1011
105
0.746
1055
3600
3.667
0.2727
4.042
1.237 x 10 4
Appendix B
Wise Rules
Page 52
-------
Table B-2: Emission Coefficients by Fuel Type
Emission Coefficients
Pounds C02 per Unit Volume or Mass Pounds C02 per Million Btu
Petroleum Products 1
Aviation Gasoline
Distillate Fuel (No. 1, No. 2, No. 4 Fuel Oil and Diesel)
Jet Fuel
Kerosene
Liquefied Petroleum Gases (U>G)
Motor Gasoline
Residual Fuel (No. 6 Fuel Oil)
18.355 per gallon
770.9 16 per barrel
22.384 per gallon
940. 109 per barrel
2 1.439 per gallon
900.420 per barrel
2 1.537 per gallon
904.565 per barrel
12.200 per gallon
512.415 per barrel
19.641 per gallon
824.939 per barrel
26.033 per gallon
1,093.384 per barrel
152.717
161.386
159.690
159.535
138.846
157.041
173.906
Natural Gas and Other Gaseous Fuels ^^^^^^^^^^^^^^^^^^^^^^H
Methane
Hare Gas
Natural Gas (Pipeline)
Propane
Electricity 1
116.376 per 1000 ft3
133.759 per 1000 ft3
120.593 per 1000 ft3
12.669 per gallon
532.085 per barrel
Varies depending on fuel
115.258
120.721
117.080
139.178
used to generate electricity*
^—~
Mif!lB
Anthracite
Bituminous
Subbituninous
Ugnite
3852. 156 per ton
4921.862 per ton
3723.952 per ton
2733.857 per ton
227.400
205.300
212.700
215.400
Renewable Sources ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^H
Geothermal Energy
Wind
Photovoltaic and Solar Thermal
Hydropower
Wood and Wood Waste**
Municipal Solid Waste**
Nuclear 1
0
0
0
0
3814 per ton
1999 per ton
0
0
0
0
0
221.943
199.854
0
Source: DOE/EIA, Form EIA-1605 Voluntary Reporting of Greenhouse Gases, Instructions, 1997, Appendix B.
*For average electric power emission coefficients by state, see Table B-3.
**Fuel cycle emissions are likely to be less than the direct emissions because all or part of the fuel is renewable. These biofuels contain carbon that is part of the natural carbon
balance and that will not add to atmospheric concentrations of carbon dioxide.
Page 53
Wise Rules
Appendix B
-------
Table B-3: Electricity C02 Emission Factors by State
C02 Emission Factors
Ibs/kWh short tons/MWh metric tons/MWh
C02 Emission Factors
Ibs/kWh short tons/MWh metric tons/MWh
New England Region
Connecticut
Maine
Massachusetts
New Hampshire
Rhode Island
Vermont
0.715
0.966
1.459
0.852
1.091
0.159
Mid Atlantic Region
New Jersey
New York
Pennsylvania
0.774
1.036
1.286
East-North Central Region
Illinois
Indiana
Michigan
Ohio
Wisconsin
0.866
2.171
1.576
1.807
1.343
West-North Central Region
Iowa
Kansas
Minnesota
Missouri
Nebraska
North Dakota
South Dakota
1.686
1.703
1.627
1.783
1.288
2.303
0.912
South Atlantic Region
Delaware
District of Columbia
Florida
Georgia
Maryland
North Carolina
South Carolina
Virginia
West Virginia
1.855
2.649
1.294
1.220
1.356
1.350
0.688
1.107
2.005
0.358
0.483
0.729
0.426
0.546
0.080
0.387
0.518
0.643
0.433
1.086
0.788
0.904
0.671
0.843
0.852
0.814
0.891
0.644
1.151
0.456
0.928
1.324
0.647
0.610
0.678
0.675
0.344
0.554
1.003
0.324
0.438
0.662
0.386
0.495
0.072
0.351
0.470
0.583
0.393
0.985
0.715
0.820
0.609
0.765
0.773
0.738
0.809
0.580
1.045
0.410
0.842
1.192
0.587
0.553
0.615
0.612
0.312
0.502
0.909
Alabama
Kentucky
Mississippi
Tennessee
Arkansas
Louisiana
Oklahoma
Texas
Mountain Region
Arizona
Colorado
Bllilfll
1.369
1.930
1.075
1.335
0.684
0.965
0.537
0.668
0.621
0.869
0.487
0.606
llfllifflffll
1.286
1.388
1.672
1.552
1
0.798
2.001
0.269
1.553
1.875
1.405
1.990
2.194
0.643
0.694
0.836
0.776
0.399
1.000
0.134
0.777
0.937
0.703
0.995
1.097
0.584
0.629
0.758
0.704
0.362
0.908
0.122
0.704
0.850
0.637
0.903
0.995
•TOM
0.756
0.235
0.306
0.378
0.118
0.153
0.343
0.107
0.139
^Wj^W^^^^B
0.031
1.291
0.016
0.646
0.014
0.586
Montana
Nevada
New Mexico
Utah
Wyoming
California
Oregon
Washington
Alaska
Hawaii
U.S. Average
Source: DOE/EIA, Form EIA-1605 Voluntary Reporting of Greenhouse Gases,
Instructions, 1997, Appendix C.
Appendix B
Wise Rules
Page 54
-------
c
or WISE RULES
Boilers
Boiler Wise Rule 1
Effective boiler load management techniques, such
as operating on high fire settings or installing smaller
boilers, can save over 7% of a typical facility's total
energy use with an average simple payback of less
than 2 years.
Boiler Wise Rule 2
Load management measures, including optimal
matching of boiler size and boiler load, can save
as much as 50% of a boiler's fad use.
Boiler Wise Rule 3
An upgraded boiler maintenance program including
optimizing air-to-fuel ratio, burner maintenance, and
tube cleaning, can save about 2% of a. facility's total
energy use with an average simple payback of 5
months.
Boiler Wise Rule k
A comprehensive tune-up with precision testing
equipment to detect and correct excess air losses,
smoking, unburned fuel losses, sooting, and high
stack temperatures, can result in boiler fuel savings
of 2% to 20%.
Boiler Wise Rule 5
A 3% decrease in flue gas 02 typically produces
boiler fad savings of 2%.
Boiler Wise Rule 6
Using over fire draft control systems to control excess
air can save 2% to 10% of a boiler's fuel use with typ-
ical equipment costs of $1,500.
Boiler Wise Rule 7
Using a characterizable fuel valve to match the air/fuel
ratios across the load range can save 2% to 12% of a
boiler's fuel use at relatively low cost.
Boiler Wise Rule 8
Converting to air or steam atomizing burners from
conventional burners can reduce boiler fuel use by
2% to 8%.
Boiler Wise Rule 9
Every 40°F reduction in net stack temperature (outlet
temperature minus inlet combustion air temperature)
is estimated to save 1% to 2% of a boiler's fad use.
Boiler Wise Rule 10
Stack dampers prevent heat from being pulled up the
stack and can save 5% to 20% of a boiler's fad use.
Boiler Wise Rule 11
Direct contact condensation heat recovery can save
8% to 20% of a boiler's fuel use, but costs may be rel-
atively high.
Boiler Wise Rule 12
Preheating combustion inlet air can save about 3% of
a facility's total energy use with an average simple pay-
back of 8 months.
Boiler Wise Rule 13
Minimizing energy loss from boiler blowdown can
save about 2% of a. facility's total energy use with an
average simple payback of less than 1 year.26
Boiler Wise Rule 14
Removing a 1/32 inch deposit on boiler heat transfer
surfaces can decrease a boiler's fuel use by 2%; removal
of a 1/8 inch deposit can decrease boiler fuel use by
over 8%.
Appendix C
Wise Rules
Page 55
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Boiler Wise Rule 15
Slowdown heat recovery is a proven technology that
can reduce a boiler's fuel use by 2% to 5%.
Boiler Wise Rule 16
For every 11 °F that the entering feedwater temperature
is increased, the boiler's fuel use is reduced by 1%.
Boiler Wise Rule 17
Changing from manual blowdown control to auto-
matic adjustment can reduce a boiler's energy use by
2% to 3% and reduce blowdown water losses by up
to 20%.
Steam Systems
Steam Wise Rule 1
An effective steam trap maintenance program can
save 3% of a. facility's total energy use with an average
simple payback of 2 months.
Steam Wise Rule 2
An effective steam trap maintenance program can
reduce a boiler's fuel use by 10% to 20%.
Steam Wise Rule 3
Repairing steam system leaks can save 1% of a
facility's total energy use with an average simple
payback of 3 months.
Steam Wise Rule k
A single high-pressure steam leak (125 psi) can result
in energy losses costing from $660 to $2,200 per year
(8,760 hrs). A single low-pressure steam leak (15 psi)
can result in energy losses costing $130 to $480 per
year (8,760 hrs).
Steam Wise Rule 5
Insulating steam lines can save 1% of a. facility's total
energy use with an average simple payback of 10
months.
Steam Wise Rule 6
Vapor recompression saves 90% to 95% of the energy
needed to raise the steam to the same pressure in a
boiler.
Steam Wise Rule 7
Measures to reduce heat loss from condensate in a
steam system can save over 1% of a. facility's total
energy use with an average simple payback of 8
months.
Process Heating
Process Healing Wise Rule 1
Proper heat containment can save about 2% of a
facility's total energy use with an average simple
payback of 9 months.
Process Healing Wise Rule 2
Insulating a furnace with refractory fiber liners can
improve the thermal efficiency of the heating process
by up to 50%.
Process Healing Wise Rule 3
Recovering waste heat from furnaces, ovens, kilns,
and other equipment can save 5% of a typical facility's
total energy use with an average simple payback of 16
months.
Process Healing Wise Rule k
Recovering waste heat through a recuperator can
reduce a kiln's energy use by up to 30%; regenerators
can save up to 50%.
Process Healing Wise Rule 5
Each percent of moisture removed by air drying
lumber reduces the kiln's energy use by 50 to 85 Bui
per board foot.
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Appendix C
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Process Healing Wise Rule 6
Variable fan speed control in the lumber industry
can reduce dry kiln airflow by 20% and reduce the
kiln's energy used during surface drying by as much
as 50%.
Process Healing Wise Rule 7
Installing expert systems for kiln secondary control
can reduce a cement kiln's energy use by up to 3%.14
Process Healing Wise Rule 8
New clinker cooler technologies that optimize heat
transfer conditions can reduce a cement kiln's energy
use by up to 6%.
Process Healing Wise Rule 9
Direct firing with natural gas in place of indirect
steam heating has the potential to save 33% to 45%
of process heating energy use. Payback times may range
from a few months to 6 years.
Process Healing Wise Rule 10
Direct electric heating (infrared, microwave, or dielec-
tric) can reduce process heating energy use by up to
with typical payback periods of 1 to 3 years.
Waste Heat Recovery and
Degeneration
Heal Recovery/Cogen Wise Rule 1
Recovering waste heat can reduce a typical facility's
total energy use by about 5% with an average simple
payback of 16 months.
Heat Recovery/Cogen Wise Rule 2
Heal Recovery/Cogen Wise Rule 3
Preheating furnace combustion air with recovered
waste heat can save up to 50% of the furnace's energy
use. Heat Recovery/Cogen Table 1 summarizes
typical fuel savings for a natural gas furnace.
Heal Recovery/Cogen Wise Rule k
Reducing net stack temperature (outlet temperature
minus inlet combustion air temperature) by 40°F is
estimated to reduce the boiler's fuel use by 1% to 2%.
Using an economizer to capture flue gas waste heat
and preheat boiler feedwater can reduce a boiler's fuel
use by up to 5%.
Heal Recovery/Cogen Wise Rule 5
Removing a 1/32 inch deposit on boiler's \\ezt transfer
surfaces can reduce a boiler's energy use by 2%;
removing a 1/8 inch deposit can reduce a boiler's
energy use by over 8%.
Heal Recovery/Cogen Wise Rule 6
Gas turbines with heat recovery equipment typically
cost from $600 to $l,000/kW. Larger gas turbines
may be available for half the cost per kW
Heal Recovery/Cogen Wise Rule 7
A typical regeneration project may reduce primary
energy consumption (including fuel inputs at off-site
powerplants for purchased electricity) for steam and
electricity generation by 10% to 15%.
Heal Recovery/Cogen Wise Rule 8
degeneration systems can save about 9% of a typical
facility's primary fuel inputs for on-site energy use
(i.e., including fuel savings at off-site powerplants for
purchased electricity) with an average simple payback
of 34 months.19 (Savings are calculated by dividing
total energy savings, including powerplant inputs, by
total facility energy use.)
Appendix C
Wise Rules
Page 57
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Compressed Air Systems
Compressed Air Wise Rule 1
Efficiency improvements can reduce compressed air
system energy use by 20 to 50%.2
Compressed Air Wise Rule 2
Efficiency improvements to compressed air systems
can save approximately one-half percent of a. facility's
total energy use.
Compressed Air Wise Rule 3
Using cooler intake air for compressors can reduce
compressed air system energy use by 1% per 5°F reduc-
tion in intake air temperature.5 The payback period
for this measure is usually less than two years.
Compressed Air Wise Rule k
Using cooler intake air for compressors can save
almost one-half percent of a. facility's total energy use
with an average simple payback of 5 months.
Compressed Air Wise Rule 5
Installing or adjusting unloading controls can reduce
compressed air system energy use by about 10%.
Compressed Air Wise Rule 6
Upgrading controls on screw air compressors can
reduce a. facility's total energy use by about 1% with
an average simple payback of 8 months.
Compressed Air Wise Rule 7
Reducing air compressor pressure can reduce a. facili-
ty's total energy use by about one-half percent with an
average simple payback of 4 months.
Compressed Air Wise Rule 8
Reducing air compressor pressure by 2 psi can reduce
compressor energy use by 1% (at 100 psi).
Compressed Air Wise Rule 9
Eliminating or reducing compressed air usage for cer-
tain activities can reduce a. facility's total energy use by
more than one-half percent, with an average simple
payback of 6 months.16
Compressed Air Wise Rule 10
Repairing air leaks can reduce compressed air system
energy use by 30% or more.
Compressed Air Wise Rule 11
Repairing air leaks can reduce a. facility's total energy
use by about one-half percent, with an average simple
payback of 3 months.
Compressed Air Wise Rule 12
It takes approximately 2.5 to 5.0 kWh to compress
1,000 ft^ of air to 100 psi.21'22 Each psi reduction in
compressed air loss from the distribution system (at
100 psi), reduces the compressor's energy use by more
than one-half percent.
Compressed Air Wise Rule 13
Air compressor waste heat recovery can reduce a facil-
ity's total energy use by about 1.8% with an average
simple payback of 10 months.
Compressed Air Wise Rule 14
For every 1 psi increase in air compressor pressure
gained by periodic filter changes, air compressor energy
use is reduced by about 0.5%. Changing dryer filters at
8 or 10 psi drop per filter can eliminate this waste.
Compressed Air Wise Rule 15
For every 11°F decrease in air compressor working tem-
perature, gained by careful maintenance of intercoolers,
air compressor energy use will decreased by 1%.
Page 58
Wise Rules
Appendix C
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Process Cooling
Process Cooling Wise Rule 1
Installing energy efficient chillers and refrigeration
systems can save 1.2% of a facility's total energy use
with an average simple payback of 23 months.
Process Cooling Wise Rule 2
"Free cooling" with cooling tower water can reduce a
facility's total energy use by about 1 percent with an
average simple payback of 14 months.
Process Cooling Wise Rule 3
Free cooling can reduce cooling system energy use by as
much as 40% depending on location and load profile.
Process Cooling Wise Rule k
Increasing chilled water temperature by 1°F reduces
chiller energy use by 0.6% to 2.5%.4 (See Process
Cooling Table 1 for data on specific chiller types.)
Process Cooling Wise Rule 5
Reducing condenser pressure by 10 psi can decrease
refrigeration system energy use per ton of refrigeration
(kW/ton) by about 6%.
Process Cooling Wise Rule 6
For each 1°F decrease in condenser cooling water
temperature, until optimal water temperature is
reached, there is a decrease in chiller energy use by
up to 3.5%.
Process Cooling Wise Rule 7
Eliminating heat losses from leaks and improper
defrosting can reduce refrigeration system energy use
by 10% to 20%.
Process Cooling Wise Rule 8
Freezing products in batches rather than continuously
can reduce freezing process energy use by up to 20%.
Process Cooling Wise Rule 9
Installing variable speed drives in place of constant
speed systems can reduce cooling system energy use
by 30% to 50%, depending on load profile.
Appendix C
Wise Rules
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KEY REFEKES
3M Company, "Rules of Thumb: Quick Methods of
Evaluating Energy Reduction Opportunities," 1992.
Clevenger, L. and J. Hassel, "Case Study: From Jump
Start to High Gear—How DuPont is Cutting Costs by
Boosting Energy Efficiency," Pollution Prevention Review,
Summer 1994, p. 301-312.
Garay P.N., Handbook of Industrial Power and Steam
Systems, Fairmont Press.
Mercer, A., Learning from Experiences with Industrial
Drying Technologies, Centre for the Analysis and
Dissemination of Demonstrated Energy Technologies
(CADDET), 1994.
O'Callaghan, P., Energy Management, McGraw-Hill,
England, 1993-
Oregon State University, AIRMaster Compressed Air
System Audit and Analysis Software. To inquire about the
AIRMaster Software package, call the Energy Ideas
Clearinghouse at 1-800-373-2139.
Payne, F.W., Thompson, R.E., Efficient Boiler Operations
Sourcebook, 4th Edition, Fairmont Press, 1996.
Rutgers University, Office of Industrial Productivity &
Energy Assessment (OIPEA), Modern Industrial
Assessments: A Training Manual, Version I.Ob, (prepared
for the U.S. DOE Office of Industrial Technology and
the U.S. EPA, 1995). Available at:
http://oipea-www.rutgers.edu/site_docs/pdfdocstm.html
Rutgers University OIPEA, "Useful Rules of Thumb for
Resource Conservation and Pollution Prevention,"
March 1996.
Taplin, H.R, Boiler Plant and Distribution System
Optimization Manual, Fairmont Press, 1991.
Talbott, E.M., Compressed Air Systems: A Guidebook on
Energy and Cost Savings, 2nd Edition, Fairmont Press,
1992.
Turner, W.C., Energy Management Handbook, 3rd
Edition, Fairmont Press, 1997
For assistance in preparing your Climate Wise Action
Plan or your Voluntary Greenhouse Gas Emissions
Report (Form EIA-1605), call the Climate Wise
For information on the U.S. EPA Energy Star Programs,
call 1-888-STAR-YES.
For information on the U.S. EPA Waste Wise Program,
call 1-800-EPA-WISE.
For information on U.S. DOE Industrial Assessment
Centers, call 1-800-DOE-EREC.
For information on the U.S. DOE Motor Challenge
Program, call 1-800-862-2086.
For information on the U.S. DOE Compressed Air
Challenge, call 1-800-559-4776.
Appendix D
Wise Rules
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