U.S. Environmental Protection Agency Industrial Environmental Research     EPA-600/7-77-035
Off ice of Research and Development Laboratory                  .. ^O77
                 Research Triangle Park. North Carolina 27711 Apfll 1977
        HEAT PUMPS:
        SUBSTITUTES FOR OUTMODED
        FOSSIL-FUELED SYSTEMS
        Interagency
        Energy-Environment
        Research and Development
        Program Report

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                    RESEARCH REPORTING SERIES


Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into seven series. These seven broad categories
were established to facilitate further development and appljcation of environmental
technology. Elimination of traditional  grouping was consciously planned to foster
technology transfer and a maximum  interface in related fields. The seven series
are:

     1.  Environmental Health Effects Research
     2.  Environmental Protection Technology
     3.  Ecological Research
     4.  Environmental Monitoring
     5.  Socioeconomic Environmental Studies
     6.  Scientific and Technical Assessment Reports (STAR)
     7.  Interagency Energy-Environment Research and Development

This report has been assigned to  the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from the effort
funded under the 17-agency Federal Energy/Environment Research and Development
Program. These studies relate to EPA's mission to protect the public health and welfare
from adverse effects of pollutants associated with energy systems. The goal of the
Program is to assure the rapid development of domestic energy supplies in an environ-
mentally-compatible  manner by providing the necessary environmental data and
control technology. Investigations include analyses of the transport of energy-related
pollutants and  their health and ecological effects; assessments of, and development
of, control technologies for energy systems; and integrated assessments of a wide
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This report has been reviewed by the participating Federal Agencies, and approved
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This document is available to the public through the National Technical Information
Service, Springfield, Virginia 22161.

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                                             EPA-600/7-77-035
                                                    April 1977
    HEAT  PUMPS: SUBSTITUTES FOR
OUTMODED  FOSSIL-FUELED SYSTEMS
                             by

                          E.A. Picklesimer

                     Lockheed Missiles and Space Co., Inc.
                          P.O. Box 1103
                       Huntsville, Alabama 35807
                        Contract No. 68-02-1331
                           Task No. 11
                       Program Element No. EHE623


                      EPA Task Officer: Lewis D. Tamny

                   Industrial Environmental Research Laboratory
                    Office of Energy, Minerals, and Industry
                     Research Triangle Park, N.C. 27711
                           Prepared for

                   U.S. ENVIRONMENTAL PROTECTION AGENCY
                     Office of Research and Development
                        Washington, D.C. 20460

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                           CONTENTS


Section
        FIGURES                                            iv

        TABLES                                              v

   I     INTRODUCTION                                       1

  II     BASIC HEAT PUMP CONCEPTS AND COMPONENTS    2

 III     CURRENT SYSTEMS                                  8

        3.1 Capacity                                         8

        3.2 Adequacy in the Commercial and Residential        8
            Sector

 IV     POTENTIAL OF HEAT PUMP TO REPLACE FOSSIL   12
        FUELED EQUIPMENT

        4.1 New Systems                                    12
        4.2 In Place of Outmoded Fossil Heating/Electric      12
            Air Conditioning Systems

  V     ECONOMIC  COMPARISON OF HEAT PUMPS           13
        WITH FOSSIL FUELED SYSTEMS

 VI     PROJECTIONS  OF THE RATE OF MANUFACTURE,    18
        SUPPLY AND INSTALLATION OF HEAT PUMPS IN
        THE COMMERCIAL AND RESIDENTIAL SECTOR AS
        REPLACEMENTS FOR OUTMODED FOSSIL FUEL
        FIRED EQUIPMENT

 VII     SUGGESTION FOR FUTURE RESEARCH AND          24
        DEVELOPMENT

VIII     RESULTS AND  CONCLUSIONS                        26

 IX     COMPARISON OF RESULTS WITH THOSE ARRIVED   28
        AT IN EPA REPORT NO. 200-045-013

        REFERENCES                                       29

        APPENDDC:  Typical Heat Pump Arrangements         30
                               iii

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                            FIGURES

Number

 2-1    Simplified heat pump flow diagram in cooling mode
          showing use of switchover valve  to reverse flow
          of refrigerant                                      2

 2-2    Efficiency                                           4
                               *
 2-3    Coefficient of performance (COPn),  heating mode        5

 2-4    Coefficient of performance (COPC),  cooling mode       6

 3-1    Relative reliability of today's heat pump systems       9

 3-2    Water as heat source-sink and water as the medium
          to provide simultaneous heating and cooling (fixed
         refrigerant circuit—water flow reversed)             11
 5-1    Seasonal heating cost comparison for residential
         application—heat pump vs. gas-fired furnace          14
                                                      i
 5-2    Seasonal heating cost comparison for residential
         application- -heat pump vs. oil-fired furnace           15

 7-1    Typical heat pump COP vs. outdoor  temperature,
         5-ton split system                                   25
 A-l   Air as heat source-sink and air as heating and
         cooling medium (fixed air circuits—refrigerant
         flow reversed).  Throttling valve used to regulate
         refrigerant effect                                    30
 A-2   Air as heat source-sink and air as heating and
         cooling medium (fixed air circuits refrigerant
         flow reversed)                                      32
 A-3   Water as a heat source sink and air  as heating and
         cooling medium (fixed air and water circuits—
         refrigerant flow reversed).  Throttling valves used
         to regulate refrigerant effect                         32
                                 iv

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                            TABLES
Number

 5-1    Heating costs, single family residence,  1500 ft^.
         southeastern United States                           17

 6-1    New housing starts                                   20

 6-2    Number of heat pump units manufactured in U.S.
         (commercial and residential, single and split units)    21

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                             SECTION I

                           INTRODUCTION
Clean burning premium fuels such as natural gas and distillate oil No. 2
are marketed primarily as combustion fuels in the commercial and res-
idential sector in the United States.  This extensive use of premium fuels
is at the expense of the most abundant energy sources in the United States,
bituminous coal, oil shale and some lignite. Modern combustion technol-
ogy has now progressed to the point where these "dirtier" fuels  can be
used efficiently as boiler fuels with the use of modern fuel processing
and stack-gas cleaning technologies (i.e., wet scrubbers,  dry scrubbers
and catalytic oxidation) to reduce the pollutant emissions  to such a level
as to be competitive with the "premium" fuels.

In order to reduce significantly the demand for clean premium fuels by
the major consumers, the more abundant fuels  can be used for genera-
ting electrical energy to be supplied as a clean energy source in the
commerical and residential sector.  Consideration of this  means of re-
ducing the demand for clean premium fuels should be included in all
future  discussions of an Energy Program by the U. S. Government.  The
potential benefits that might result from the primary use  of electrical
energy by the commercial and residential sector are that the premium
fuels can then be used in energy demand areas  which are  not amenable
to fuel substitution and in the manufacture of chemicals  and fertil-
izer where feed stock shortages  already exist.  Also, the  conversion of
outmoded "premium" fossil fuel heating systems to heat pumps in the
residential and commercial sector where the electricity is generated by
steam coal or nuclear power plants may significantly reduce our national
consumption of scarce natural gas and fuel oil.

An independent assessment has been made of the state of  the art relative
to the development, capacity, adequacy and application of  the heat pump
as a potential replacement for fossil-fueled equipment designed to serve
in the space heating and cooling mode. A projection has been made of
the rate at which heat pumps could be manufactured, supplied, and in-
stalled in the  commercial and residential sector as replacements for
for outmoded fossil fueled equipment whose service life has been ex-
hausted and is scheduled for replacement.

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                              SECTION II


         BASIC HEAT PUMP CONCEPTS AND COMPONENTS


 The key components of a heat pump system are  shown in Figure  2-1.
 The main function of the compressor is to pump  a refrigerant vapor
 from a relatively low suction pressure to a higher head pressure.  The
 suction and head pressures  that a compressor experiences are a  func-
 tion of the design, the ambient temperatures,  and possible abnormal
 fault situations which develop during the life of a heat pump system.
                     Compressor rf^\     -^       ^ Switchover valve
                                               (heating position)
Figure 2-1  - Simplified Heat Pump Flow Diagram in Cooling Mode Show-
             ing Use of Switchover Valve to Reverse Flow of Refrigerant

Under cooling conditions, the refrigerant  is pumped from the compres-
sor through the condenser or outdoor coil. Upon leaving the outdoor
coil in liquid form, the refrigerant travels through the evaporator or
indoor coil, and here, as it changes from  a liquid into a gas, it removes
heat from the interior, thereby cooling the indoor  coil.  The gas is then
drawn back into the compressor where it  is compressed again into a
very-high-pressure hot gas, which is liquefied or  condensed in the out-
door coil.

The first heat pumps were  more or less simplified versions  of this
cooling unit, and were obtained by merely reversing the flow of refrig-
erant as shown in Figure 2-1.  With the aid of a switchover  valve, the
outdoor condensing unit became, in essence, the evaporator, and the
indoor evaporator became in essence, the condensing unit.  The hot gas,
therefore, was pumped indoors, where it gave off  heat as it was  con-
densed into  a liquid in the indoor section.  The liquid was then pumped

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into the outdoor section now  the  evaporator where the refrigerant
changed back into a gas, absorbing heat during this process from out-
door air.

The four basic heat pump designs for space heating and cooling employ:
(1)  air as the heat source-sink and  air  as the heating and cooling
medium; (2)  air as the heat source-sink and water as  the heating and
cooling medium; (3) water as  heat source-sink and air as the heating
and cooling medium;  or (4) water  as heat source-sink and water as the
heating and cooling medium.

Each of these basic designs can supply the required heating and cooling
effect by changing the direction of the refrigerant flow, or by maintain-
ing a fixed refrigerant circuit and changing the direction of the heat
source-sink  media.  A third alternative is to incorporate an interme-
diate transfer fluid in the design.  In this case the direction of the fluid
is changed to obtain heating or cooling and both the refrigerant and heat
source-sink  circuits  are fixed.  The fixed refrigerant circuit designs,
generally referred to as the indirect type  of application, are becoming
increasingly  popular, particularly in the larger capacities.

The basic designs are quite flexible  and are readily  adaptable to a
number of different types of applications.  Flow diagrams, together with
a brief description, are given for  some of the more typical arrangements
in Appendix A (Ref. 1).

It is easy to  confuse the heat pump coefficient of performance (COP) with
efficiency (Eff) since  they both represent an index of performance of a
cycle.  Efficiency is defined as the desired effect divided by the energy
required to produce the desired effect. For a fossil furnace as  shown in
Figure 2-2, the efficiency is
                               x  100% <  100%
Classically, the efficiency is less than 100%.  However for a heat pump
operating on the Brayton cycle, the index of performance is the COP which
can be greater than 100%.  In the heating cycle the COP^ of the heat pump
is, by definition, the desired effect (heat into the home, QJJ) divided by the
energy required to produce the  desired effect (electrical input — W) as
shown in Figure 2-3 or
                             x  100% > 100%.

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                   Thermal Energy Released
                    by Fuel Combustion, T,r
                                          rl
                                   Q
                                    H
                          Fossil
                         Furnace
              (Desired Effect-
              Heat into Home)
              W
                           Ambient Heat
                           Sink
                   Efficiency =
                                  W
                                 Q
      x 100%  < 100
                                  H
                   Since W   =  QH ~ QL
                     Figure 2-2 - Efficiency
For the cooling cycle, the heat pump COPC is defined as the desired
effect (heat removal from the home, Q,.) divided by the energy re-
quired to produce the desired effect (electrical  input — W) as shown in
Figure 2-4 or
                       COPC =
W
    x
100%

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                     Desired Effect — Heat
                       into Home at T
                                  Q
                                   H
           W

           Electrical
           Energy
                        Ambient Heat
                        Source at TT
              COPh    =  -^j2- x  100% >  100%
              Since Q  = W +
Figure 2-3 - Coefficient of Performance (COP,), Heating Mode

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                   Ambient Heat Sink at T
                                         H
                                 Q
                                  H
          W

          Electrical
           Energy
                 Desired Effect — Heat Removed
                       From Home  at TT
where
                              QT
                    COP  =  -^ x 100%
                        c     W
                       QL=QH-W
   Figure 2-4 - Coefficient of Performance (COPc), Cooling Mode

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Efficiency normally refers to the transfer of energy from a high tem-
perature (TTT) source (fuel) to a low temperature (Tjj) receiver whereas
COP refers to the transfer of energy from a low  temperature  (TL)
source to a high temperature (Tj^) receiver to produce a desired effect.

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                            SECTION III


                         CURRENT SYSTEMS
3.1  CAPACITY
There are many companies which produce quality heat pumps for both
residential and commercial applications.  The Air-Conditioning and
Refrigeration Institute lists 32 participants in their Directory of Certi-
fication, January 1 through June 30, 1976 (Ref. 2).  The heat pump man-
ufacturers offer  a.  complete  range of heat pump sizes  from  small
residential units (i. e., less than 5 tons =  60,000 Btuh cooling) to large
commercial  systems  (i.e., greater  than 500,000 Btuh cooling).  Larger
systems may be designed by utilizing multiple units.  A  few of the
largest manufacturers of heat pumps  are the Trane Company, General
Electric, Lennox Industries and Carrier.   There arc many other small
companies which  manufacture heat pumps only for the residential
market (i.e., less than 5 tons).

3.2  ADEQUACY AND APPLICATION IN THE COMMERCIAL AND
     RESIDENTIAL SECTOR

When sized properly for the particular application,  heat pump systems
have performed adequately in both the residential and commercial sec-
tors since the middle 1960s.   Heat pumps have been available for resi-
dential application since the early 1950s.  Based on its concept and
efficiency, the heat pump was  an immediate success in 1950. History
can be simplified by  stating that the heat  pump was  marketed before it
was sufficiently developed.  It  failed  from the  reliability  standpoint
during the 1950s.   The compressor, the key component of the heat pump,
was not  designed to withstand the high head and suction pressure which
can result during conditions of switchover, high ambient temperatures
and possible abnormal fault conditions.  These conditions require high
electrical input resulting  in high mechanical stresses in bearings, crank-
shafts, and valves  producing early compressor failure.  By the early
1960s, recognition of these problems resulted in compressor redesign,
high and low pressure cutoff switches and other protective devices for
heat pump systems.  With many more improvements, today's heat pump
systems are as reliable as the fossil fuel heat systems with electric  air
conditioning  as  shown in Figure 3-1 (Ref. 3).

The future acceptance of heat pumps  for  both industrial aad-Residential
applications  depends on the total annual cost to* own. a3a^«wea&£e a heat
pump system r'eJative to other systems as distcvjssect iajS^fcp^p V.  Cur-
rent residential heat pump systems are cornpietifcfve only wheia used as a
total space comfort conditioning system.

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   >N
   •»->
   r-J  +->
   '^  TO
   -2  <"
   .53  E
   
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for the reheat cycle and for the perimeter areas.  This latter method
of heating and cooling can add considerably to the operating cost.

Water can be used as the heat source-sink and as the medium to pro-
vide simultaneous heating and cooling to the conditioned space.  In this
arrangement the refrigerant flow is always in the same direction,  going
from the compressor to the condenser, then to the cooler. The major
refrigerant  components together with all refrigerant piping and acces-
sories can be purchased as a compact package with  a hermetically
sealed refrigerant circuit. The hot and cold water piping, the indirect
and cooling  surfaces, and  other needed accessories  for a particular
installation  can,  in turn, be installed by the contractor

During a considerable portion of the year the heating and cooling re-
quirements  of the structure may be in balance, so that an external heat
source or sink is not required. Thus, the heat removed from the zones
requiring cooling is automatically transferred to the condenser circuit
and made available to the  zones requiring heat. In this way the coeffi-
cient of performance is materially improved to give a considerable
saving in operating cost.

Figure 3-2  (Ref. 1) illustrates how simultaneous heating and cooling
are readily available at all times. For the basic heating cycle, valves
are positioned to path 1-3 to provide two water circuits.  Pump 1 cir-
culates the  warm water through the condenser-liquid receiver,  valves
A, the conditioner  coils, and  valves B in a closed loop.  Pump 2 cir-
culates the  cold water  through the cooler, valve  D, the  exchanger
(where heat is taken from the well water), and valve E back to pump  2
to repeat the cycle.

For the basic cooling  cycle, valves are positioned to path 1-2.  Pump 1
circulates the warm water through the condenser,  valve E, the ex-
changer  (where heat is rejected to the well water), and valve D  back to
pump 1.  Pump 2 circulates the cold water through the cooler (where
heat is taken from the water by the refrigerant),  valves A, the condi-
tioner coil,  and valves B back to pump 2 in a closed loop.

During the intermediate cycle, simultaneous heating and cooling are
provided by modulating valves D and E to maintain the desired tempera-
tures in the two circuits.  Usually, during this cycle the water  is main-
tained at 100 to 120 F in the condenser circuit and 45 to 50 F  in  the
chiller circuit.  The excess heating and cooling are  rejected from the
exchanger to the well water.  The well water can be supplied directly
to the condenser and chiller circuits instead of through the heat ex-
changer, as  indicated.  The direct use of the well  water is most attrac-
tive,  provided  it  is  chemically  acceptable  and does  not  unduly
contaminate the heat transfer  surfaces.
                                10

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                                                 •_ INTERNAL ~-:
                                                 CONDITIONER"
                                                 •/-:; COIL is
                                        HEAT; VALVE POSITION 1-3
                                        COOI_:  '    "
                                        VALVE 384 MODULATE TO
                                        MAINTAIN THE DESIRED TEMP
                                        WELL WATER AND WASTE HEAT
                                        AS HEAT SOURCE-SINK.
                                        WATER SUPPLIES SIMULTANEOUS
                                        HEATING AND COOLING TO
                                        CONDITIONED SF»C£.
                                        FIXED REFRIGERANT CIRCUIT
                                        BETWEEN COMPRESSOR (NOT
                                        SHOWN), CONDENSER AND
                                        COOLER,
             VALVES "C" £OUrtLlZE
             THE PRESSU'i? BETWEEN
             THE CIRCUITS
Figure 3-2 - Water as Heat Source-Sink and Water as the  Medium to
              to Provide Simultaneous Heating and Cooling (Fixed
              Refrigerant Circuit — Water Flow Reversed)


The compressor (not shown) delivers the hot compressed  gas to the
condensed-liquid receiver where it is  liquefied,  giving  up its latent
heat of condensation to the circulating water.  From the condenser the
liquid refrigerant flows through an  expansion valve to the  cooler (where
it changes into a gas), absorbing the heat of vaporization by reducing
the temperature of the  circulating water, and then returns to the com-
pressor.
    •v

The heat pump system  can be a versatile cooling system and is  cleaner
and as quiet  as  comparable  fossil fueled systems but the heat pump
system may  require more maintenance (see Section V).
                                  11

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                            SECTION IV


       POTENTIAL OF HEAT PUMP TO REPLACE FOSSIL
                      FUELED EQUIPMENT
If air conditioning is not necessary, a heat pump heating system is not
competitive with a comparable fossil fueled heating system based on cap-
ital cost and operating cost.  Therefore, only the total space comfort-
conditioning concept will be considered in the subsequent discussion.

4.1  NEW SYSTEMS

Utilization  of the heat  pump  system is most economical when the
system is designed  as the initial space comfort-conditioning system in
the new home or the new commercial facility.  Once the decision to uti-
lize electric air conditioning has been made, the decision to use a heat
pump system over a fossil fueled/electric air  conditioning system can
be made by considering the total annual cost of each system, the avail-
ability of fuel, the dynamics of the fossil-fueled/electric price ratio
and the climate (which affects both the amount of heating and cooling
required and the efficiency of the system) (Refs. 1, 5).  (See Section V
for economic analysis.)

4.2  IN PLACE OF OUTMODED FOSSIL HEATING /ELECT RIG AIR
     CONDITIONING SYSTEMS

In discussions with heating and air conditioning contractors, there are
many factors to consider in replacing an  outmoded fossil fueled heating/
air conditioning system with a heat pump system.

If the air circulation system already exists, installation of the heat pump
can be very competitive with replacing the  outmoded system.  However,
if the air handling system does not exist, installation can be  very diffi-
cult and expensive.

In many cases, either the outmoded fossil fueled heating system or the
electric air  conditioning system may need replacing but not both.   It
may be difficult to justify the  capital expense of a heat pump system as
opposed to replacing only the  fossil fueled furnace or an electric air
conditioner.

If a home or business was wired initially for a  fossil fueled heating
system,  a heat pump system requires an additional electrical load
which may necessitate the additional expense of rewiring.

Thus heat pump retrofit is most attractive  if the air handling system
is  already in place  and both the fossil fueled heating and electric  air
conditioning systems need replacement.
                                12

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                             SECTION V


     ECONOMIC COMPARISON OF HEAT  PUMPS WITH FOSSIL
                        FUELED SYSTEMS
The heat pump should only be sold under the aegis of a total-space
comfort-conditioning concept.  The heat pump system can be econom-
ical except when air conditioning is excluded. In that case, the total
annual cost of owning and  operating a heat pump system will be higher
than that of a gas fired heating system without air conditioning, thus
making the heat pump unattractive economically to the homeowner.

To the average homeowner paying  3^/kWhr  for  electricity but only
0.82^/kWhr for  gas, the fact that electricity can be competitive with
gas for space heating is difficult to accept.  The disparity between the
two seems even greater when the higher  installation and maintenance
costs of the heat pump are considered.  However,  there are several
other factors in an electric/gas  cost analysis that, more  often than not,
offset the basic  cost differential. Among them are special rates for
space heating and water heating, the decision to use electric air con-
ditioning, and the dynamics of the relative gas/electric price ratio
where the price of  gas has grown faster than that  of electricity.  With
a worsening of the  gas shortage, escalation  in gas prices  is likely to
continue.

An economic analysis was made by Lockheed-Huntsville comparing the
heat pump, gas fired and oil fired furnaces with electric air  conditioning
on the total-space comfort-conditioning concept.   Equipment efficiencies
assumed are: gas  fired furnace, 45%;  oil fired furnace, 45%; electric
air-conditioning, 300%.  The heating value of natural gas was assumed
to be  1000 Btu/ft^.  Figure 5-1  shows the result of economic compari-
son of the heat pump and the gas fired furnace.  The current retail cost
of natural gas for residential use is about 24j^/therm (equal to . 82^/kWhr)
and for electricity  is about 3j^/kWhr giving a unit  energy  cost difference
ratio  of 8.  At an energy cost difference ratio of 8 (see dashed lines in
Figure  5-1), the  heat pump is more expensive to operate by about 25%
for a  coefficient  of performance (COP) of 3.  However, if  electric rates
increase by 1.5  and gas rates triple by 1980 as forecast (Refs. 6 and  7),
the heat pump will  be more economical than the gas fired furnace as
shown in Figure  5-1.  Figure 5-2 shows the results of a comparison of
the heat pump and an oil fired furnace  burning No. 2 fuel oil with a heat-
ing value of 140,000 Btu/gal.  The  current retail  cost  of  No. 2  oil is
about 39f£/gal and 3^/kWhr for  electricity giving  a unit  energy cost
ratio  of 13. If the cost of  electricity increased by 1.5 and the cost of
No. 2 fuel oil triples by 1980 (Refs. 7, 8), the heat  pump will be  more
economical on a  total space-comfort conditioning  concept. Figures 5-1
and 5-2 do not account for captial cost, depreciation and maintenance.
                               13

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CO
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 I
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as

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 fn
 0)
 CO
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 bO
 n)
 cu
 ffi
       100' •
        80 • •
         60' •
        -20"
                    1.  Heating cost difference ratio vs unit
                       energy cost ratio

                    2.  Gas furnace efficiency = 45% with
                       electric air conditioner in summer

                    3.  Gas heating value - 1000 Btu/ft
                        Seasonal Heat Pump Coefficient
                        of Performance (COP)
                                                           Equal
                                                           Operating
                                                           Line
      Figure 5-1 - Seasonal Heating Cost Comparison for Residential
                   Application — Heat Pump vs Gas-Fired Furnace
                                14

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                           Notes:


                           1.  Heating cost difference ratio vs unit
                              energy cost ratio

                           2.  Oil furnace  efficiency = 45% with
                              electric air conditioning in summer

                           3.  No. 2 heating oil - 140,000 Btu/gal
                              Heat Pump COP
                                                   Equal
                                                   Operating
                                                   Line
     Figure 5-2 - Seasonal Heating Cost Comparison for Residential
                 Application — Heat Pump vs Oil-Fired Furnace
                                   15

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Table 5-1 shows a comparison of the annual cost of operating a heat
pump, a gas furnace with electric air conditioning and an oil furnace
with electric air conditioning in a residential application.  Depreciation
has been figured on a  15-year equipment life and 40-year life for duct
work.  Capital cost has been figured on a 7% mortgage ratio of the total
installed cost.  Maintenance has been figured on a percentage of the orig-
inal equipment cost with a factor based on relative equipment complexity.
Data were obtained by surveying Heating and Air Conditioning Contractors
in the Southeastern United States.  Note that the heat  pump  system is
more expensive to own and operate based on 1975 retail fuel prices.  As -
suming a threefold price increase in natural gas and fuel oil as compared
to a 1.5 increase in electricity by  1980, the heat pump will be less expen-
sive to  own and operate than both oil and gas furnaces with electric air
conditioning.

Annual  costs for heating and air conditioning depend upon the location
within the U. S.  In the Northern U. S. the mean temperature  may be 10
to 20 degrees lower than in the Southern U. S.  Therefore,   heat pump
efficiencies would be  somewhat less but  fossil furnace efficiencies
would be somewhat greater than in the South.  Therefore the operating
cost for the alternatives presented may change by as  much as 20% de-
pending on location but the trends would not change. In Alaska, almost
no homes are equipped with air conditioning; based  on the low efficiency
of a heat pump at low  ambient temperatures and the current fuel prices,
a heat pump is  not  economical compared with a similar fossil fueled
system when considering the heating mode only.

On the other hand, in Southern Florida many homes  and commercial bus-
inesses do not have a  heating  system; more than 95%  of air  conditioning
systems are conventional electric.

In  some locations, homes and commercial businesses utilizing electric
heating receive reduced electric rates due to the utility's reduced costs
in delivering larger amounts of electricity to a  customer. Although the
actual operating cost  would  depend on the particular rate, the reduced
rates can make heat pumps  more economical  (Ref. 7).
                              16

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                 Table 5-1

HEATING COSTS, SINGLE FAMILY RESIDENCE,
  1500 FT3, SOUTHEASTERN UNITED STATES
Item
Operating 1975
Costs 1976
1977
Depreciation

Capital Cost
Maintenance
Total Annual Cost
1975
1980
1985
Heat Pump
$ 281
$ 422
$ 632
$1,800<£ 6.7% = $120
$1.200 (S 2.5%= $ 30
$3.000 x 0.07 = $210
$1,100 x 0.04 - $ 44

$ 685
$ 826
$1036
Gas Furnace
with Electric
Air Conditioning
$ 237
$ 535
$ 803
$1400 @ 6.7% = $ 93
$1200 @ 2.5%= $ 30
$2600 x 0.07 = $182
$ 200 x 0.02 = $ 4
$ 500 x 0.03 = $ 15
$ 561
$ 859
$1127
Oil Furnace
with Electric
Air Conditioning
$ 260
$ 603
$ 905
$1400 @ 6.7% = $ 93
$1200 (§ 2.5% = $ 30
$2600 x 0.07 = $182
$ 800 x 0.03 = $ 4
$ 500 x 0.03 = $ 15
$ 604
$ 947
$1249
Energy Costs
Electric
3 //kWH
4.5
6.75


Gas
24 //them-.
72
108


Fuel Oil
40 //gal
120
180


Annual Load
Keating - 0.4 x 108 Btu/yr
Q
Cooling - 0.4 x 10 Btu/yr










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                             SECTION VI

     PROJECTIONS OF THE RATE OF MANUFACTURE, SUPPLY
    AND INSTALLATION OF HEAT PUMPS IN THE COMMERCIAL
          AND RESIDENTIAL SECTOR AS REPLACEMENTS
        FOR OUTMODED FOSSIL FUEL FIRED EQUIPMENT


6.1  PROJECTIONS OF THE RATE OF MANUFACTURE OF HEAT
     PUMPS

In communicating with representatives of companies manufacturing heat
pumps, about 154,000 heat pump units were manufactured during 1975
(Refs.  6, 9, and 10).  Approximately 139,000 units of 5 tons or less were
manufactured and sold for residential use and about 15,000 units of greater
than 5  tons were sold for use in commercial applications.  Thus, 90% of
all heat pumps manufactured during 1975 were for the residential market.

Due to the reduced supply of natural gas and heating oil, manufacturers
of heat pumps are projecting an industry-wide production rate of 250,000
to 275,000 (Refs. 6, 9) heat pump units for supply and installation during
1976.  The manufacturers feel that the percentage of residential and
commercial heat pumps will remain the same.  Less than 5% of this is
for retrofit application.

6.2  REPLACEMENT RATE

In order to estimate the rate at which outmoded fossil fueled heating
systems could be replaced with heat pumps in the residential and com-
mercial sector, let

         N.  =  total number of heat pump units  needed for both
                residential  and commercial  sector
         N   =  maximum nuber of residential heat pumps units
                required
         N   =  maximum number  of replacement heat pump units
          r     in residential sector

         L   =  gas heating system life
          o
         L   =  oil  heating system life

         N   =  number of heat pump units needed for new homes
          n                   r   r

         N   =  number of residential gas customers
          g
         F   =  fraction of residential customers using gas for
           ^    space heating
         N   =  number of residential oil customers
          p
         F   =  fraction of residential customers using oil for
           0    space heating


                                18

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 Then the maximum number of heat pumps required for replacement of
 of outmoded fossil fired equipment in the residential sector is


                            N . F     N  . F-
                      N   =           + -
                               Lg       Lo

Data from the American Gas Association (Ref. 6) indicate that there were
41,336,500 residential gas customers in the U.S. in 1974; of those, 84%
of the customers used natural gas for space heating with an average con-
sumption of 1140 therms.  Data from the Department of  Commerce (Ref.
8) indicate that there were 16,827,000 residential heating oil customers
in the U.S. in 1975; of those, 99% of the customers  used  oil for  space
heating with an average annual consumption of 900 gallons.

Assuming an average life of a gas and an oil heating system to be 15 years
(Ref. 2), the maximum number  of replacement heat  pump units required in
the residential sector  for outmoded fossil fueled systems is
                                                                    (2)
                         41,336,500 (0.84)
                    r ~         15


                         16.827,000 (0.99)
                                15

                      =  3.43 x 10  heat pump units
                                        year

N   represents the maximum number of heat pump units needed per year
to replace all of the outmoded fossil heating systems in the residential
sector during the next 15 years.  Since data were not available for  1975,
Nr is based on the number  of gas customers  in 1974.   Due to the gas
shortage, it is unlikely that this number has increased. Obviously, not
every fossil fueled heating system installed in 1965 will be replaced in
1980; some will be replaced sooner, others later.  However, assigning
finite lifetimes to each type of fossil fueled heating system should not
affect the relative replacement rate.

Table 6-1 (Ref. 8) shows the annual number of new housing starts during
the last four  years and  an estimate  of  starts for 1976.  Although the
number of new housing starts has been decreasing since  1972, the  esti-
mate for 1976 is up.  For simplicity,  assume that  the number of  new
housing starts per year during the next 15 years is 1,250,000.  If heat
pumps are installed in all new homes, the number of units required will
be

                N  = 1,250,000  units year.                          (3)
                  n
                              19

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                             Table 6-1

                  NEW HOUSING STARTS (REF. 8)
Year
1972
1973
1974
1976 (Est.)
Number of New
Starts
2,378,500
2,057,500
1,352,500
1.3 to 1.7
Housing


x 106
Therefore, the number of residential heat pump units needed as replace-
ments for outmoded fossil fueled heating systems and for installation in
new homes is
                N  =  N  + N
                      r     n
(4)
                  _  4 ,„   ,,.6  heat pump units
                         X          year
If one assumes that the ratio of the number of residential units manufac-
tured to the number of commercial units remains 9/1, the total numbers
of units needed is
                Nt = N (1 + 1/9)


                   - 5  15   10^  heat pump units
                          x          year
(5)
In order  to put this number into perspective, Table 6-2 (Refs. 10, 11)
shows the number of heat pump units manufactured in the U.S. from 1972
to 1975 and an estimated production for 1976. The numbers include both
single and split units for residential (i.e., less than 5 tons) and commeri-
cal use.  It is apparent that the number of heat pumps needed for replace-
ment and new applications is 5.15 x 10°/154,000 = 33 times greater than
the total number of units manufactured in 1975.

Several comments are in order at this point.  Although heat pump manu-
facturers feel that their industry could respond to any demand rate for heat
pump-units by the general public (Refs. 10, 11), several of the large manu-
facturers expressed concern about a large number of untested and un-
reliable heat pump units on the market today; with a high demand for heat
                                20

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                              Table 6-2

     NUMBER OF HEAT PUMP UNITS MANUFACTURED IN U. S.
         (Commercial and Residental, Single and Split Units)
Year
1972
1973
1974
1975
1976 (Est.)
Number of Units
97,000
120,000
128,000
154,000
250,000
pump systems, sale of a large number of these units could cause a simi-
lar situation that developed in the heat pump market in tin- 1950s (see
Section 3.2). The second point is that possibly as many as one-third of
the outmoded fossil fueled heating  systems in both the residential and
commercial sector cannot be replaced due to the problems in the physi-
cal arrangement of the existing fossil fueled heating system using hot
water pipes, convection radiators, etc.  Also, it may not be practical to
replace another third  of the outmoded fossil  fueled heating /electric air
conditioning from an economic standpoint because only the heating or the
cooling system may need replacing, not both. A more realistic manufac-
turing rate  may be less that 25% of Nt or less than  1.3 x 10^ heat pump
units per year which is still 8.4 times the 1975 industry-wide heat pump
manufacturing rate.

6.3  ESTIMATES OF  POSSIBLE REDUCTION IN DEMAND OF PREMIUM
     FUEL

Assume that all of the residential customers using natural gas and heat-
ing oil for  space heating replace their outmoded fossil fuel equipment at
the time of  failure with heat humps.  As  indicated in Section 6.2, there
were 41,336,500 natural gas customers in 1974 where 84% of the customers
used natural gas for space heating with the average  annual usage of 1140
therms. Assuming a heating  value of  1000  Btu/ft^, the maximum savings
of natural gas would be
    Saving
41,336,500 (0.84) (1140
          res. gas  =
therm
 year
(10
                                                            Btu
                                                          therm'
                                    103 Btu/ft3
                                                                     (6)
                     8.8 x 1012 ft3/yr
                                21

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Similarily, there were 16,827,000 residential heating oil customers in
1974 where 99% of those customers used oil for heating with an average
annual consumption of 900 gal year (Ref. 12).  The maximum savings of
heating oil would be

       Saving
             res. oil  = 16,827,000 (.99) (900 gal/year)               (7)

                      = 1.5 x 10   gal/year


Data on the number of residential gas customers for 1975 have not been
finalized, but due to the shortage of supplies, the totals have not increased.
There were 3,392,000 commercial users of natural gas in 1974 with an
average annual consumption of 6,761 therms. The American Gas Associa-
tion (Ref. 13) estimates that two-thirds of this consumption was used for
space  heating.  The maximum savings of natural gas in the commercial
sector is
           comm. gas = 	=	s
                                       10  Btu/ft
Saving              3,392,000 (0.667) (6,761
                                           _

                                                              (8)
                      =  1.529 x 1012 ft3/year


Since there is no information on commercial fuel oil consumption for
space heating, assume the ratio of the number of commercial to residen-
tial fuel oil customers is the same  as the ratio of the number of commer-
cial to residential gas customers.

Then, the number of commercial fuel oil customers =


                            3,392,000
                1 A 827 000
                16,827,000


                          = 1,380,000


Also, assume that the ratio of the average annual consumption of com-
mercial to residential natural gas is  the same as the ratio of the average
annual consumption of commercial to residential fuel oil for  space heating.
                                22

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Then, the average consumption of fuel oil for  commercial space heating =
If all of the commercial fuel oil heating systems were replaced with heat
pumps, the maximum savings of heating oil would be

             Saving
                   comm. oil = 1,380,000  (4238) =

                                0.585 x 1010 gal/year


Therefore, the maximum savings in the commercial and residential sector
that may be realized by replacing the outmoded gas heating systems with
heat pumps  is from (8) and (6)


            Savings ag =  10.3 x 1012 ft3/year
                   O
Similarity, the maximum savings of heating oil from (7) and (11) would be


                    5 oil

                         =  1.357 x 106
                                      oil/day
Savings^  = 2.08 x 10   gal/year

           = 1.357 x  10  barrels of premium fuel
The above savings would be realized at the end of a 15-year period when
all of the outmoded fossil fueled systems had been replaced.  As indicated
in Section 6.2, the actual savings of natural gas and heating oil due to the
replacement of outmoded fossil fueled  systems with heat pumps would
probably be less  than the maximum due to the  inability to  install heat
pumps in some residences and the failure of only one component of the
total space heating system. A conservative savings of 25%  of the maxi-
mum  might be more realistic.
                                23

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                             SECTION VII


    SUGGESTION FOR FUTURE RESEARCH AND DEVELOPMENT
 Significant improvements have been made in the design of heat pumps
 since  1950.  The compressor has been  redesigned to withstand  high
 stresses.  Safety devices  such as high and low pressure cutoff switches
 have been added to heat pump systems to prevent  operation at abnormal
 conditions.  However, more research and development is still needed to
 make the heat pump more economical relative to other systems.

 Improvements are needed in the area of low temperature operation.  As
 indicated in  Figure 7-1, the coefficient  of performance decreases rather
 dramatically as the ambient temperature decreases.  Evaporator icing
,is a problem at temperatures below 32  F.

 Research is also needed in the area of improved working fluids and im-
 proved materials to extend compressor  component life.

 Additional studies  should be made to assess the impact of space heating
 electrification on local and regional air  quality due to increased load at
 electric generation plants. Since a significant number of fossil fueled
 heating customers do not use  electric air conditioning presently, electri-
 fication of space heating could significantly increase the  demand for
 electricity.  Thus, an analysis should  be  made  to  determine  if the
 nation1 s electrical generating capacity could be expanded Rapidly enough
 to meet increased demand since some utilities have drastically reduced
 their construction schedules.  Current lead times for bringing base elec-
 tric generating plants on line are more than seven years  for fossil fueled
 plants and 12 years for  nuclear plants.

 In order to encourage the use of heat pumps to conserve premium fossil
 fuel, to reduce air pollution from stationary sources and to help meet the
 national goal of reducing our dependence on imports  of natural gas and
 oil, a  study  should be made  on the use of direct incentives to encourage
 customers to convert outmoded fossil systems to  heat pump systems.
 Such incentives could be provided by the various federal agencies in the
 form of:  (1) reduced electric  rates for  heat pump customers; (2) tax de-
 ductions or an increased depreciation rates for conversion; and/or  (3)
 lower VA and FHA interest  rates for conversion to heat pump systems;
 or  (4) tax credits for heat pump installation and insulation improvement
 to applicable standards  where appropriate.
                                24

-------
    50
    40' •
S.  30' '
I
h
01
o,  20-
s
O
o
     o- •
   -10-
                 Coefficient of Performance (COP)
    Figure 7-1 - Typical Heat Pump COP vs Outdoor Temperature,

                 5 ton Split System
                            25

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                            SECTION VIII

                    RESULTS AND CONCLUSIONS
The widespread use of the heat pump in both the residential and com-
mercial sectors as a total comfort conditioning system will, to a large
extent,  be controlled by the  consumer.  Modern heat pump systems are
as reliable  and competitive in capital cost as fossil heating/electric
air conditioning systems. Although residential heat pump systems cur-
rently cost  about 25% more to operate than comparable fossil heating/
electric air conditioning systems based on current retail energy costs,
the future availability of natural gas and oil for space heating is ques-
tionable.  Even today, many utilities have decided not  to add any more
residential  natural gas customers to their system until further notice;
in those cases many contractors are installing heat pumps  exclusively
in new homes. Certain commercial heat pump systems are already
more economical today than fossil fueled heating/electric air condition-
ing systems especially when both heating and cooling are required in
different areas of a building at the same time.

The retail price  of natural gas and oil has increased much faster than
the price of electricity.  Also, the natural gas and petroleum industry
may be deregulated in the future which may cause a significant increase
in the retail price of natural gas and oil relative to  electricity.  There-
fore,  heat pump systems may  be as economical to operate as fossil
fueled heating/electric air conditioning systems in the near .future.

Heat  pumps may be used to  replace outmoded fossil heating/electric air-
conditioning systems  especially in those locations where the air handling
system already exists.  By converting outmoded fossil heating electric
air conditioning systems to  heat pump systems, the premium fossil fuel
saved may  be used in applications where  conversion is not possible and
where a "critical" shortage already exists such as the manufacture
of fertilizer.

Assuming that the energy needed for  space heating electrification comes
from new coal fired or nuclear units,  spacing heating electrification
using heat pumps could reduce the nation's consumption of natural gas
by 10.3 x 1012 ft^/year and premium fuel oil (i.e., No. 2 or better) by
1.357 x 10^ barrels/day.  Since current  base load power  plant lead
times are so  great and utilities have  drastically cut their construction
schedules,  it  is questionable at this time  if the utilities can meet the
increased demand due to space heat electrification. Electric generation
capacity currently exists for those customers using electric air condi-
tioning. However, there are many  customers in areas such as the
densely populated Northeastern U. S. where fossil fueled heating is uti-
lized without  electric air conditioning; in these cases, electrification of
the heating systems would result in the need for additional generating
capacity.
                               26

-------
Although the projected demand for heat pump units may be significantly
greater than the current industry growth rates due to electrification of
space heating with heat pumps, this demand (see Section 5) can be met
by current heat pump manufacturers.
                              27

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                            SECTION DC


   COMPARISON OF RESULTS WITH THOSE ARRIVED AT IN EPA
                    REPORT NO. 200-045-013
This study agrees with the results arrived at by EPA Report No. 200-
045-013 that electrification of fossil fueled heating systems in the resi-
dential and  commercial sector can result in a significant reduction in
the demand for premium fuels for use in those areas •where conversions
cannot be made and shortages already exist.  If the electrical energy re-
quired for these conversions were provided by  coal-fired or nuclear
power plants, these reductions in end use consumption of premium fossil
fuels would represent a real  reduction in our national consumption of
natural gas and fuel oil.

Although the projected rates  of manufacture, supply and installation of
heat pump units needed for  replacement of outmoded  fossil fueled
systems and new applications may be more than eight times the industry
wide heat pump manufacturing rate during 1975, it is felt that the heat
pump industry could meet this projected demand.
                                                       i
This study  disagrees  with the EPA Report No. 200-045-013 conclusion
that the promotion of  electrification of space heating should be instituted
at the present time. A brief  study  should be made  to determine how
much additional generating capacity is needed and if it will be available
in view of reduced utility construction programs  and increased power
plant lead times.  Information necessary for this  study will be available
in the near  future from the Department of Commerce and the Federal
Power Commission (See Section VIII).
                               28

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                            REFERENCES
 1.  Ambrose, E. R., Heat Pumps and Electric Heating, Wiley, New York,
    1966.

 2.  Directory of Certification, Air Conditioning and Refrigeration Insti-
    tute, Arlington, VA., January 1-June 30 1976.

 3.  Juttermann, "Heat Pumps in Large Buildings," Heiz-Luft.  -Haustechn.,
    Vol. 25, No. 4, April 1974, OA - Trans - 939, pp. 124-130.

 4.  "Moore Turns to Heat Pumps," Power, p. 24, November  1973.

 5.  O'Neil, J.F., "The  Economics of the Heat Pump," Engineering Journal,
    Novermber, 1965, pp. 42-46.

 6.  American Gas Association,  Department of Stastics, Personal Com-
    munication, May  21, 1976.

 7.  Spaite P., Energy Consultant, Cincinnati, Ohio, Personal Communi-
    cations, June 10,  1976.

 8.  U.S. Department of Commerce, Office  of Consumer Affairs, Statistics
    Division, Washington, D. C., Personal Communication, May 25, 1976.

 9.  Carrier Corporation, Syracuse, New York, Private Communication,
    May 20, 1976.

10.  Carrier Corporation, Syracuse, N. Y., Personal Communications,  May
    25,  1976.

11.  General Electric, Central Air Conditioning Product Department, Pri-
    vate Communications,  May 21, 1976.

12.  U.S. Department  of Commerce, Bureau of the  Census, Washington,
    D. C., June 3,  1976.

13.  Gas Facts, 1975,  American Gas Association, Washington, D. C.
                                29

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                             APPENDIX
              TYPICAL HEAT PUMP ARRANGEMENTS
An air heat source-sink design using air as the  heating and cooling
medium illustrated in Figure A-l,  is by far the most universally used,
particularly for the residential and smaller commercial installations
having a cooling load of about 25 tons, or lower...
                                                   ACCESSORIES
                                               A OIL SEPARATOR
                                               B SUCTION LINE ACCUMULATOR
Figure A-l
Air as Heat Source-Sink and Air as Heating and Cooling
Medium (Fixed Air Circuits — Refrigerant Flow Reversed).
Throttling Valve Used to Regulate Refrigerant Effect
Conventional refrigerant practice can be followed in the selection and
arrangement of the equipment, except that it is desirable to have gravity
drainage of the liquid refrigeration from the outdoor coils and the con-
ditioner coils to the liquid receiver.  The  diagram  also  indicates the
probable location  of an oil separator in  the  discharge line, and  of a
liquid refrigerant-oil accumulator in the suction line.  These accesso-
ries are generally used on all except the small integral designs in order
to assure proper  oil  return and prevent  liquid flood-back to the com-
pressor.

In this design,  heating and cooling are obtained by changing the direction
of the refrigerant flow.  Two fixed independent air circuits are employed,
consisting of the outdoor coil circuit and the  conditioner coil circuit.
During the cooling cycle the four-way valve  is positioned to paths  1-2
and 3-4.  The compressor delivers the hot compressed refrigerant gas
through the four-way valve,  path  1-2, to the  outdoor coil where it is con-
densed, giving  up  the  latent heat of condensation to the outside air.  From
                                30

-------
the outdoor air coil the liquid refrigerant flows through the check valve
to the liquid receiver and then through the throttling valve to the con-
ditioner  coil.  In the conditioner coil the liquid refrigerant is  changed
into a gas that absorbs the heat of vaporization from the air going to the
conditioned space.  From the conditioner coil the refrigerant  gas returns
through the four-way valve, path 3-4, to the compressor to repeat the
cycle.

During the heating  cycle the four-way valve is positioned to path 1-3 and
2-4. The compressor  delivers  the  hot  compressed refrigerant gas
through the four-way valve, path 1-3, to the conditioner coil where it is
condensed, giving up the latent heat of condensation to the air  going to
the conditioned space.  From the conditioner coil the liquid refrigerant
flows through the check valve to the liquid receiver and then through the
throttling valve to the  outdoor coil.  In the outdoor coil the liquid refrig-
erant changes into  a gas that absorbs the heat of vaporization from the
outside air. From the outdoor coil the refrigerant gas returns through
the four-way valve, path 2-4, to the compressor to repeat the  cycle.

Figure A-2 is a modification of the basic air-to-air heat pump cycle.
Two additional check valves and a liquid throttling valve have  been added
to the basic cycle and the expansion valves,  solenoid valves, liquid re-
ceiver, and oil separator have been eliminated.  In this design the liquid
refrigerant is used both to boil the condensed refrigerant from the suction
line accumulator and to superheat the suction gas entering the compres-
sor. The throttling valve,  C, regulates the refrigerant flow by maintain-
ing a predetermined liquid temperature leaving the condenser. The heat
source coil, either the indoor or outdoor coil depending upon the  cycle,
will operate in a flooded condition because of the absence of an expan-
sion valve.  It is  important, therefore, that the suction line accumulator
be adequately designed to prevent liquid floodback to the compressor.

The main advantage cited for this design is the elimination of  the thermo-
static expansion valves and the need for a pressure-suction differential
to obtain the desired refrigeration effect. Consequently, the system can
operate on the cooling cycle at extremely low outdoor temperatures,  and
by maintaining the  predetermined liquid temperature can  operate at rea-
sonably constant  head pressures during both the heating and cooling cycle.

Figure A-3 shows a typical flow diagram of a system employing water as
the heat  source-sink and using air as the heating and cooling medium.

In this  cycle, heating and cooling are obtained by changing the direction
of the refrigerant flow. Two separate fixed circuits are  employed, con-
sisting of a water circuit through the condenser-cooler and an air circuit
over the conditioner coil.  During the cooling cycle the four-way valve is
positioned to paths 1-2 and 3-4.  The refrigerant path is  from the com-
pressor through the four-way valve,  path  1-2, the condenser-cooler,  the
check valve, the liquid receiver, the expansion valve,  the  conditioner coil,
the four-way valve, path 3-4, back to the compressor to repeat the cycle.
The refrigerant gas is liquefied in the condenser-cooler  by giving up its
                               31

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               V&LVE MSrT
                   1-2 *NO 3-4
                PAT* I-J AND 1-4
»•COMPRESSOR
• SUCTION LINt ACCUMULATOR
C- THKOTTUNO VALVE USED TO HEOULATE
         CFVECT.
Figure A-2  - Air as Heat Source-Sink and Air as Heating and Cooling
              Medium (Fixed Air  Circuits Refrigerant Flow Reversed)
               TO HEAT SOURC€-SINK
                4 way_yaty£
               CO0UNG PATH t-Z AH?) 3-
               «E*fi»6 ^-ITM I-S A'<3 Z-
       *ccrssomes
    A-OIL SEPARATOR
    »• SUCTION LI HE ACCUMULATOR
   Figure A-3 - Water as a Heat Source Sink and Air as Heating
                 and Cooling Medium (Fixed Air and Water Cir-
                 cuits — Refrigerant Flow Reversed). Throttling
                 Valves Used to Regulate Refrigerant Effect
 latent heat of condensation to the water and is changed back into a gas
 in the conditioner coil by absorbing its heat of vaporization from the
 air going to the conditioned space.

 During the heating cycle the four-way valve is positioned to paths 1-3
 and 2-4, The refrigerant path is from the  compressor through the
                                  32

-------
four-way valve, path 1-3, the conditioner coil, the check  valve, the
liquid receiver, the  expansion valve, the condenser-cooler, the f our -
way valve, path 2-4, then back to  the  compressor to repeat the cycle.
Conversely to the process of the cooling cycle, the hot compressed re-
frigerant gas from the compressor  is liquefied in the conditioner coil
by giving up its heat of condensation to the air going to the conditioned
space, and is changed back into a gas  in the condenser-cooler by absorb-
ing the heat of  vaporization from the well water.

During both the cooling and heating  cycles well water is circulated by
a pump through the preconditioning  coil (if used to precool or to preheat
the ventilation  air),  then through the condenser-cooler to  the drain.
                                33

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                                TECHNICAL REPORT DATA
                          (Please read Instructions on the reverse before completing)
 . REPORT NO.
 EPA-600/7-77-035
                           2.
                                                      3. RECIPIENT'S ACCESSION-NO.
 TITLE AND SUBTITLE
Heat Pumps: Substitutes for Outmoded Fossil-Fueled
Systems
                                                      5. REPORT DATE
                                                        April 1977
                                                      6. PERFORMING ORGANIZATION CODE
 . AUTHOR(S)
E.A. Picklesimer
                                                      8. PERFORMING ORGANIZATION REPORT NO.

                                                       LMSC-HREC PR D496880
9. PERFORMING ORGANIZATION NAME AND AOORESS
 Lockheed Missiles and Space Co. ,  Inc.
 P.O. Box 1103
 Huntsville, Alabama  35807
                                                      10. PROGRAM ELEMENT NO.
                                                       EHE623
                                                      11. CONTRACT/GRANT NO.

                                                      68-02-1331, Task 11
12. SPONSORING AGENCY NAME AND ADDRESS
 EPA, Office of Research and Development
 Industrial Environmental Research Laboratory
 Research Triangle Park, NC  27711
                                                       13. TYPE OF REPORT AND PERIOD COVfchf D
                                                       Task Final; 4-6/76	
                                                      14. SPONSORING AGENCY CODE
                                                        EPA/600/13
15. SUPPLEMENTARY NOTES E PA
61, 919/549-8411 Ext 2851.
                              officer for this report is Lewis D.  Tamny, Mail Drop
 16. ABSTRACT Tne repOrt reviews the state-of-the-art relative to development,  capacity,
 and adequacy of the heat pump as a potential replacement for outmoded fossil-fueled
 heating and cooling systems in the residential and commercial sector.  Projections
 are made of the rate at which heat pumps need to be manufactured and installed in
 the commercial and residential sectors as the projected service life of fossil-fuel
 equipment expires.  The conclusion is reached that the heat pump is economical only
 as a total space comfort system. Based on January 1, 1976, fuel prices, the heat pump
 is about 25% more expensive to operate than comparable  fossil-fueled heating systems.
 If the trend of increasing fuel prices continues, the heat pump will be more economical
 to operate than comparable fossil-fueled heating systems by 1980.
 17.
                              KEY WORDS AND DOCUMENT ANALYSIS
 a.
                 DESCRIPTORS
                                           b.lDENTIFIERS/OPEN ENDED TERMS
                                                                   c. COSATI Field/Group
 Air Pollution
 Heat Pumps
 Heating
 Cooling
 Energy Conversion
 Energy Conversion Heat Sources
 Refrigerating Map.hlnfiry
 18. DISTRTBUTION ST/i	
                                          Air Pollution Control
                                          Stationary Sources
                         13B
                         13A
                                                                   10A
                                                                   10B
18. DISTRTBUTION STATEMENT

 Unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
    39
                                           20. SECURITY CLASS (Thispage)
                                           Unclassified
                                                                    22. PRICE
EPA Form 2220-1 (9-73)
                                         34

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