Note: Descriptions are shown in the official language in which they were submitted.
3~3~
BRIEF SUMMARY OF INVENTION
. _ _
This invention is directed to the problem of low
efficiency of heat pump systems due to low ambient
temperature.
It is well known that a heat pump, in its heating mode,
wil] reach a "balance point" at some value of ambient air
temperature. Simply put, this point is reached when the
heat pump system requires supplemental heat in orcler to
maintain the inside air temperature demanded by the
thermostatO
Some systems have been employed in which the heat pump
is simply switched-off at this "balance point" with all of
the heat thereafter being supplied by a more conventional
heating system, such as a furnace. Still other conventional
systems have employed control systems in which the heat pump
system is stil~ utilized down to its limit of ambient
temperature (e.g. 10 F.), while increasingly supplementing
its heat output, below the "balance point", by more con-
ventional means) such as electrical resistance heaters, etc.
Whereas such systems have also employed defrosting
heaters Eor the outside coil (essential to avoid "blinding"
of the coil and to retain good heat transfer with the
circulated ambient air), it has not been recognized that the
efficiency of a heat pump system may be artificially
restored under low ambient temperature conditions to a
sufficiently high value with minimal heat input, as to
justify, economically, this sort of "bootstrapping".
Thus, in a conventional system, when the heat available
for extraction from ambient air has reached such a low value
as to produce relatively low efficiency for the system~ in
~1
accordance with this invention, heat is applied directly to
the outside co:il in such a limited quantity as (1) artifici~
la:Lly restores the efficiency to a much higher value and
(2) does so with a net decrease in operating costs.
IN THE ~RAWINGS:
FIGURE 1 is a Eragmentary perspective view of a novel
heat exchanger of the present invention and illustrates an
"A-coil", a blower, an associated compressor and an
associated housing;
FIGURE 2 is a sectional view taken generally along line
2-2 of Figure 1 and illustrates additional details of the
heat exchanger including a heat source, such as a natural
gas burner, for augmenting the heat absorbed from ambient
air by the "A-coil";
FIGURE 3 is a longitudinal sectional view taken
generally along line 3-3 of Figure 2 and illustrates details
of the heat exchanger housing including the location of the
source of heat adjacent bottom portions of the legs of the
"A-coil";
FIGURE 4 is a sectional view taken generally along
lines 4-4 of Figure 3 and illustrates the manner in which
hot air rises within and through the absorber fins and about
the coils of the "A-coil" during the heat-augmented mode o:E
operation of the heat exchanger;
FIGURE 5 is a schematic view illustrating certain
principles of this invention;
FIGURE 6 is a perspective view of an overall heat-
exchange system utilized in conjunction with the heat
exchanger of Figures 1 through 4 as more fully detailed with
~7~
respect to a slightly modified form of the invention shown
in Figures 7 through 10 of the drawings;
FIGURE 7 is an end view of the modified heat exchanger
o:E Figures 1 through ~, and illustrates inlets and outlets
of an "A-coil", a condensation tray in which the coil is
seated with an outlet tube thereof being heated to prevent
condensate :From freezing;
FIGURE 8 is a sectional view taken generally along line
8-8 of Figure 7, and illustrates further details of the
overall system;
FIGURE 9 is an enlarged sectional view taken generally
along lines 9-9 of Figure 8, and illustrates a cold return
having an opening above inlets :Eor returning the coil
liquid to a lower end portion of the "A-coil"; and
FIGURE 10 is a sectional view taken generally along
line 10-10 of Figure 9, and illustrates further details of
the structure.
Reference is now made to Figures 1 through 4 of the
drawings in which a novel heat exchanger or heat-augmented
heat pump is generally designated by the reference numeral
10 and includes a housing 11 defined by a front wall 12, a
rear wall 13, end walls 14, 15, a bottom wall 16 seated upon
a concrete slab S,and a top wall or cover 17. The cover 17
is preferably hinged (not shown) to an upper edge portion of
the rear wall 13 so that ample access to the :interior of the
housing 11 is provided from above when the cover 17 is in
its open (not shown) position. Likewise, the end walls 14,
15 are removably secured by sheet metal screws (not shown)
to the walls 12~ 13 so that the end walls 14, 15 can he
readily removed, thus, providing ample access to interior
3~
components of the heat exchanger 10.
The height of the walls 12, 13 is less than the total
height of the end walls 14,15, as is readily apparent in
Figure l, ancl the encl walls 14, 15 are relieved at 20, 21,
respectively, as well as being provided with baffled vents
or openings 22, 23, respectively (Figures 1 and 3) in order
that air might readily circulate through the housing 11 in a
manner to be described more fully hereina-fter.
The housing 11 is also separated into a pair of chamber
means or chambers 25, 26 by a vertlcal partition or wall 27
while a horizontal partition or wall 28 having a central
opening 29 (Figure 3) separates the chamber 26 into an upper
chamber portion 30 and a lower chamber portion 31 (Figure
3). The construction of the housing 11 and particularly the
manner in which the same has been partitioned results in
highly efficient air flow as well as increased noise damping
characteristics, as will be more evident hereinafter.
Furthermore, all of the electrical components of the
electrical system (Figure 5) are located in the chamber 25
whereat they will be unaffected by moisture, condensation,
or the like which will occur in the upper chamber portion 30
of the chamber 26. The exact location oE the various
components of the electrical circui~ 40 in the chamber 25 is
of no particular importance insofar as the present invention
is concerned and are thus not illustrated in any of Figures
1 through 4 of the drawings.
The major components of the heat exchanger 10 of the
invention include compressor means 50, and "A-coil" 60, and
means 70 for providing a heat source to augment the
73~
temperature o:E outside ambient air. In addition to the
latter-noted major components, the heat exchanger includes a
blower 80 and a reversing/expansion valve 90.
Re:Eererlce is made speci:Eically to Figures 1, 3 and 4 of
the clraw:ings wherein the "A-coil" 60 is fully illustrated
ancl is a conventional off-the-shelf item which in transverse
cross-section is generally of an inverted V-shaped
configuration (Figure 4) defined by a pair of interconnected
coils 35 which are coiled through metallic heat-conductive
fins 36. An upper end portion (unnumbered) of the "A-coil"
60 is covered by a removable metallic plate 37 while bottom
end portions (unnumbered) of the "A-coil" 60 rest upon a
generally annular condensation collecting pan 38 having a
central elongated opening 39 disposed adjacent the opening
29 of the horizontal partition or wall 28 (Figures 3 and 4).
The coils 35 of the "A-coil" 60 include an inlet/outlet 41
(Figure 3) and a bottom of each leg of the "A-coil" 60 and
an inlet/outlet 42 at the top of each leg of the "A-coil".
The expression "inlet/outlet" has been utilized herein
simply to indicate that, depending upon the particular mode
of operation of the heat exchanger, refrigerant will flow
through the coils 35 in one direction at which the
refrigerant will exit from the conduit 41 while in another
mode, the refrigerant may enter the conduit 41, and the same
is true of the conduit 42. Hence, the expression
"inlet/outlet" merely refers to the direction of flow of the
refrigerant, either in its liquid or vapor phase, with
respect to the particular mode of operation of the heat
exchanger 10, as will be more fully apparent hereinafter.
The inlet/outlet or conduit 42 is connected to the
3(~
compressor 50 (Figure 3) and a conduit 43 from the
compressor 50 is connected to a heat exchanger within a
b-lilcllng~ such as a home, apartment, or the like which is to
be heated or cooled. The "interior" heat exchanger or a
similar heat utilizing device is of a conventional
construction, thus is not illus~rated but may simply be a
coil such as the "A-coil" 60, though not necessarily of the
same configuration. The conventional utilizing coil need
only have air blown through it so that during the cooling
mode, cold liquid refrigerant will absorb heat from the
interior air resulting in a decrease in interior air
temperature or alternatively when high temperature
refrigerant vapor is passed through the utilization coil,
the interior air passing through the coil absorbs the warm
air and is thereby warmed in the heating mode.
The interior or utilizer coil is connected by an
inlet/outlet conduit 44 (Figure 3) to the
expansion/reversing valve 90 and the latter is connected to
the inlet/outlet conduit 41. Thus, the flow circuit for the
refrigerant, be it in its liquid, vapor or liquid/vapor
phase is from the "A-coil" 60 through the inlet/outlet
conduit 42 to the compressor 50 thence through the conduit
43 to the interior utilization heat exchanger followed by
the inlet/outlet conduit 44, the reversing/expansion valve
90 and back to the bottom of the "A-coil" 60 through the
inlet/outlet conduit 41.
The blower 80 includes a housing 51 having an outlet 52
opening into the chamber 25 and an inlet 53 opening into the
chamber portion 26. The fan is driven by a conventional
~7~
motor 54 through conventional pulleys, a pulley belt, and
shafts, all collectively designated by the reference numeral
55 (Figure 1). The motor 54 is energized during the
operation of the heat exchanger 10 in its conventional
cool..ing mode and i.ts conventional heating mode, but not
during its heat-a~lgmenting mode in which air rises through
the "A-coil" 60 by natural convention currents, as indicated
by the headed, unnumbered arrows in Figures 3 and 4, and as
will be described more fully hereinafter.
The heat source 70 for augmenting the ambient outside
air temperature is illustrated as a natural gas burner 70
which includes an outlet burner or conduit 71 (Figure 3)
having a first leg 72 which runs along one side of the
opening 39 (Figure 4), a leg 73 transverse thereto (Figure
4), and a return leg 74 (Figure 4) which terminates in a
blind end (not shown) adjacent the left-hand edge of the
slot 39, as viewed in Figure 3. The legs 72 through 74 of
the burner or conduit 71 have a plurality of openings which
emit flames F when the natural gas is ignited by a
conventional spark or like igniter.
The operation of the heat exchanger 10 will now be
described Wittl reference first to the conventional cooling
and heating modes of operation, followed by the novel heat-
augmenting mode of operation thereof:
~7~
HEATING MODE
In the heating mode of operation of the heat exchanger
L0, the heat-exchange medium (a cold refrigerant such as
l~reon) first flows under the operation of the compressor 50
into the inlet conduit L~l at the bottom of ~he "A-coil" 60
and progressively absorbs heat from ambient air which is
drawn into the upper housing portion 30, through the coils,
into the inlet 53 of the blower, and outwardly Erom the
outlet 52 of the pump into the chamber 25 during the
energization of the pump with the latter-noted air flow
being indicated by the dashed, unnumbered headed arrows in
Figure 3. At this point, the heat source 70 is totally
unoperational and, therefore, the heat-exchange medium, as
it moves through the coils 35 in an upward direction,
absorbs heat only from ambient air which is drawn through
the "A-coil'~ 60 in the manner just described. The
progressive increase in temperature of the heat-exchange
medium transforms the same into its low pressure vapor phase
~hich is conducted via the outlet conduit 42 to the
compressor 50 which further increases the pressure, thus the
temperature, and the hot vapor phase of the refrigerant then
flows through the conduit 43 to the interior heat exchanger
(heat-exchange coil) through which air is blown absorbing
the heat of the vapor phase refrigerant, heating the
interior and, of course, progressively cooling the
refrigerant which is returned to the reversing/expansion
valve 90 through the conduit 44 which in turn returns the
now low pressure cold vapor phase and/or liquid phase of the
heat-exchange medium to the bottom of the "A-coil" 60
whereafter the cycle is continuously repeated.
~73~
COOLING MODE
For cooling purposes, the expansion/reversing valve 90
simply reverses the direction oE refrigerant flow and the
:Latter is controlled, :Eor example, in a conventional ~anner
by the circuitry 40 including the THERMOSTAT thereof which
can be set, as desired. In this manner, high pressure hot
vapor refri.gerant when pumped through the "A-coil" gives off
its heat to the air flowing therethrough lmder the influence
of the blower 80, and the high pressure cool vapor or liquid
phase is transformed by the reversing/expansion valve too a
lower pressure gas or liquid phase which when passed through
the utilization coil in the building picks up or absorbs the
heat blown through the utilization coils thereby cooling the
room or building air after which the now lower pressure
vapor phase is returned Erom the utilization device to the
compressorO
HEAT-AUGMENTING MODE
In this mode of operation of the heat exchanger 10, the
blower 80 is inoperative, and the operation and/or flow oE
the refrigerant, both as to its liquid and/or vapor phase,
is identical to that heretofore described in the "heating
mode" of the heat exchanger 10. However, it is to be
understood that in the heat-augmenting mode of operation of
the heat exchanger 10, ambient outside temperature is
relatively low, as, Eor example, 32 F. or below. The THERMO
DISC associated with the gas burner assembly of the
electrical circuitry 40 of Figure 5 senses a predetermined
temperature (32 F.) and in response thereto (1) the blower
80 is de-energized to terminate the heating mode of
30~.
operation, and ~2) the heat source 70 or gas burner assembly
ls energized by igniting the gas resulting in the hot flames
:F which under natural. convection, currents rise upwardly
through the "A-coil" 60, as indicated by the headed
unnwnbered arrows in Figure 3. The flames F are extremely
small but are spread out substantially evenly across the
bottom of the "A-coiL" 60, as is most readily apparent in
Figures 3 and 4 of the drawings. As the heat from the
Elames F rises, it first impinges under its maximum
temperature against the coldest (bottom) coils and the
liquid heat exchange medium therein with, of course, the
rerigerant flowing through the coils 35 in a direction from
the bottom of both of the legs of the "A-coil" 60 to the
tops thereof. Due to this relationship, deterioration of
the bottom coils 35 and the lower fins 36 is virtually
precluded, and because there is the greatest temperature
differential between the refrigerant in the lowermost coil
and the flames F, a major amount of heat absorption takes
place along the bottom of the "A-coil" 60 and progressively
lessens in an upward direction since the liquid cool
refrigerant progressively warms as it rises in the coils 35
until it is transformed into its vapor phase. Essentially,
there is almost total heat absorption at the time that the
vapor phase of the refrigerant exits the conduit 42 of the
"A-coil" 60 and an essentially heat-free gas (from the
flames F) escapes to atmosphere so that the burning process
approaches 100 percent. It is to be noted that the flames F
do not generate the totality of the heat necessary to
transform the refrigerant from its liquid phase to its
vaporphaseas it passes upwardly through the coils 35 of the
3~
"A-coil" 60, but rather augments or adds to the heat which
the refrigerant can absorb from the ambient air, even though
the l.atter is relatively col~ (32 F., again merely
exemE)Iary) Thus, it is totally immaterial to the operation
o.E the heat exchanger 10 as to what might be the ambient air
temperature, be it 32 F. or -24 F., etc. All that the heat
exchanger "knows'l is that there is sufficient heat available
from the flames F, which when added to that of the ambient
air temperature results in a high temperature differential
between the tota] heat input and the temperature of the
refrigerant resulting in a hot gaseous or vapor phase
exiting the "A-coil" 60 through the outlet conduit 42 for
suitable in-house heating purposes by the conventional
utilization heat exchangers heretofore noted. Thus, the
compressor 50 can utilize in an extremely efficient manner
the relatively highly heated low pressure vapor phase of the
refrigerant which would be totally impossible in the absence
of the additive heat provided by the heat source 7.
Efficiency is further increased by constructing the "A-coil"
60 of a size approximately twice that of the utilization
coil within the building to be heated so that essentially
all of the heat induced by the flames F in the reErigerant
passing through the coils 35 of the "A-coil" 60 is absorbed,
again along with absorbing the heat of the ambient air
itself, resulting in extremely efficient heat-transfer and
corresponding low operati.ng costs as well as interior build-
ing comfort by virtue of high volume/low temperature
(approximately 105 F.) interior hot air flow. An example of
the latter is evidenced by the following table which
173~
represents the total costs of heating a three-bedroom brick
bungalow utilizing the heat-augmenting mode of operation of
the heat exchanger 10 in Niagara Falls, Ontario, Canada,
Erom October 1, 1978, through April 15, 1979. The home is
occupied by five persons and the daytime temperature was
maintained at 72 F. with the nighttime temperature being
68 F. at all times.
. . . _ .. . .
Month Average Outside Energy Cost
temperature of: Elect. Gas Total
October 47 $ 4.25_ _ $ 5.25
November 37 $11.57$ 8.88 $20.45
December 27 $16.31$19.94 $36.25
January 19 $19.73$25.18 $44.91
February 12 $18.09$23.71 $41.80
March 34 $11.30$13.23 $24.53
April 1-15 32 $ 5.73$ 6.88 $12.61
Total Cost for Period ~~ $86.98 ~97.82 $~84.80
. . _ . . . _ _ _
It is believed that the latter-noted recordation of an
actual working embodiment of this invention indicates quite
emphatically the extremely efficient and low-cost nature of
the present invention and, of course, the ability of the
invention to operate under outside ambient air temperature
conditions which would render other heat pumps inoperative
or require utilization of supplementary heat sources, such
as electric heating coils which are installed in hot air
ducts as practiced by such well-known heat pump
manufacturers as York, Lennox, etc.
Another outstanding indication of the efficiency of the
present invention is that in another home heated by a
conventional gas furnace, the charges for the gas for the
month of January, 1979 was $122.71 (Canadian). The same
13
~L~8~30~
home was converted by the installation of the heat exchanger
:L0 o:E this invention and its operation for the same period
oE time (one month) in the heat-augmenting mode resulted in
a gas bill o:E $43.80 (Canadian), and the latter charge was
Eor the month of February which recorded the lowest
temperatures not only for the year, but since records have
been kept.
Other and equally important practical results are
obtained by the present invention as, for example, the
desirable utilization of condensation, as the same naturally
occurs when the heat of the flames F contact the relatively
colder coils 35 and fins 36 of the "A-coil" 60. The
condensation, thus formed, results in a film of water over
the entirety of the coils 35 and the fins 36 and, thus, the
heat of the flames F is not directly transferred onto the
metal coils 35 and the fins 36, but rather onto the film of
water which, in turn, protects the components of the "A-
coil" 60. In other words, the film of condensation or water
upon the exterior surfaces of the "A-coil" 60 serves as a
heat exchanger and protects the "A-coil" 60 from heat
damage. Secondly, after a summer's running of the heat
exchanger 10 in the cooling mode, dust collects on the A-
coil" and this is cleaned throughout the winter during the
heat-augmenting mode by the condensation constantly running
down the coils 35 and fins 36 consequently resulting in a
repetitious self-cleaning cycle of the heat exchanger 10
through repetitive seasons of use.
The heat exchanger 10 does not require a defrost cycle
of any type which is virtually commonplace throughout the
~873(~
heat pump industry.
The overall mechanical and electrical components of the
heat exchanger 10 are extremely simple, and in a manual mode
o:E operation in the absence of any type of sensing devices,
the heat exchanger 10 is virtually failure-proof during its
operati.on in the heat-augmenting mode since the only
"working" parts or components are the heat source 70 and the
compressor 50.
As was earlier noted, the condensation which is formed
in the upper chamber portion 30 is highly beneficial and,
just as importantly, the location of the electrical circuit
(Figure 5) or the components thereof in the chamber 25
prevents the circuitry from being adversely affected by such
condensation with, of course, any excess condensation which
collects in the pan 38 being drained to the exterior of the
housing 11 in the manner readily apparent from Figure 3.
Finally, due to the arrangement of the components 50,
60, 70 and 80 in the associated chambers, the sound level of
the machine is extremely low, and though the arrangement of
parts illustrated in the drawings is that preferred,
modifications thereto are considered to be within the scope
of this invention. For example, the blower 80 may be
positioned in the chamber 25 beneath the compressor 50 to
increase the efficiency during the summer or cooling mode of
operation by drawing air through the vents 23 and the
opening (unnumbered) at the top of the chamber 25 over the
compressor 50, and into the lower chamber portion 31.
Alternately, the same results can be achieved simply by
reversing the direction of the rotation of the fan motor of
the blower 80.
~3~873(3~
From the standpoint of new-home or new-building
installations, it should be noted that since the heat
exchanger 10 is the only unit necessary for all extremes of
heating and cooling, any new house, office building or the
lLke would not require a chimney, as associated flue, etc.
Furthermore, though the heat exchanger 10 has been described
thus far relative to being positioned outside of a building
which is to be heated and/or cooled, the same may be
positioned within the building so long as appropriate duct
work is provided between the heat exchanger 10 and exterior
ambient air. In the latter case, a chimney, flue or the
like remains unnecessary because the amount of heat given
off by the flames F is extremely small and is, in fact, less
than that of a conventional home gas clothes dryer which, in
most jurisdictions, need not be vented to atmosphere.
However, should a code of a particular jurisdiction require
the venting of gases, such would be a simple and inexpensive
proposition since virtually all of the heat from the flames
F is absorbed in the heat-augmenting mode and, thus, the
gases which might necessarily have to be vented from the
interior of the building to atmosphere would be cold, and
the venting duct work would either not require heat
installation or the latter would be extremely minimal.
Figure 5 represents, in simplified schematic fashion, a
basic relationship of this invention. As shown, a
conventional heat pump arrangement (in heating mode)
includes an evaporating coil Cl located outside the space to
be heated, a fan Fl and motor Ml therefor adapted to convey
ambient outside air in heat-exchange relation through or
16
~ 3~3~
past the evaporating coil Cl to cause evaporation of the
reErigerant therein, a compressor P to cause evaporation of
the reErigerant therein, a compressor P for reconverting the
evaporated refrigerant to heated, liquid phase, the heating
co~L C2 located within the heat ducting system , the
expansion valve V for reducing the pressure of the cooled
liquid phase, and the forced air fan F2 with motor M~ for
circulating air within the ducting system and the interior
space to be heated.
As îs well known, the efficiency of the heating mode of
such a system depends nonlinerally and directly upon the
outside air temperature. Dependent upon the system as a
whole, inclusive of the type of refrigerant used, the
efficiency becomes so low at some predetermined outside
temperature that it can no longer supply the heating
required. For that and other reasons, the ducting system D
will include supplementa~ heaters, usually electric to
supplement or to supplant the heat extracted from the
outside air by the heat pump. Normally, the supplemental
heaters are automatically called upon whenever the inside
temperature thermostat indicates that insufficient heat is
being supplied by the heat pump.
In many areas, the outside air temperature falls to
such low values sufficiently often as requires utilization
of the supplemental heater for protracted periods, with the
attendant increase in cost to the consumer for each BTU
delivered. It would therefore, be of significant advantage
to the consumer, as well as the energy supplier, to increase
the efficiency of the heat pump at low ambient temperature
conditions and thereby minimize utilization of the
~7;3(3~
supplemental heaters.
Surprisingly, it has been found that this can be done
by shutting-off the outside air circulation fan and
supplying sufficient augmenting heat to the evaporating coil
to complete the cycle by assuring vaporization of the
refrigerant in the coil Cl. In the arrangement illustrated,
this is effected automatically by means of the outside
temperature sensor Tl which controls the switch Sl. In
normal operation, when the inside thermostat T2 demands heat
and thus energizes the conventional contactor S2, power from
the lines _1, L2 and N energize the motor Ml and the_
compressor _ and, through the switch S2, the motor M2. The_
switch S2 is normally open but is closed by the inside coil
temperature sensor T3 when the sensor T3 detects that the
temperature of the inside coil C2 has reached a sufficient
temperature (e.g., 12~ F.) to preclude an uncomfortable
draft. When the sensor _l actuates the switch S, power is
cut-off to the motor Ml to terminate the normal air
circulation past the coil Cl. At the same time, the switch
Sl switches power to the heater H, thereby providing the
augmenting heat to the coil Cl. Typically, for best results
the sensor Tl is set to switch over to augmenting heat in
response to an ambient air temperature which has dropped to
within the range of about 32-38 F. Below this switching
temperature, the heat pump system, with augmenting heat,
will be operative upon demand by the inside thermostat T2 in
exactly the same fashion as before.
A further switch S3 is provided in the control to the
heater H and this switch is controlled by the temperature
18
~8~3~3~
sensor T~ to cut-off the heater H when the temperature of
the outside coil reaches a predetermined value (e.g., 70 Fo)
In this way, the augmenting heat supplied by the heater H is
limited to a quantity which is just sufficient to assure
h;gh eEficiency of the heat pump system.
The heater H, of course, may ta~e any form dependent
upon local conditions. For example, in areas where gas heat
is economical, the heater H may be a ccnventional automatic-
ignition gas burner assembly. In any event, the augmenting
heat is supplied in controlled quantity to the evaporating
or outside coil, the amount of heat supplied being such that
the cost of the energy so consumed is more than ofEset by
the increase in efficiency realized by the heat pump system.
Obviously, the best decrease in net operating cost will be
achieved by employing the most economical source of heat at
the heater H. In many areas, this will indicate the use of
gas heat although it is not essential in any event to use
the least expensive form of available heat energy in order
to achieve significant cost saving due to the heat
augmenting mode of operation. It is essential only that the
controlled amount of heat supplied as augmenting heat be
less costly than it would be to provide supplemental heat to
the system (in the least expensive way available) in that
amount equal to the gain achieved by the heat pump system
due to the increased efficiency thereof attained by the
augmenting heat. Stated otherwise, the increased heat
output of the heat pump system caused by its efficiency
increase due to heat augmentation must be greater than the
heat input to the heater H, and this is easily accomplished
in any practical case by controlling the amount of energy
19
3'73(~
consumed by the heater H to raise the efficiency of the heat
pump system at least approximately to optimum values.
Clearly, an optimum value will depend upon a number of
Elc tors including the inside temperature demand, the ambient
temperature, the size or capacity of the heat pump system and
the heat loss characteristics of the heated space under
prevailing conditions. Although the method herein is
intended to encompass conditions in which the rate of heat
supplied by the heater H is varied to optimize the system
under changing conditions, a simple and practical system
such as is shown in Figure 5 and wherein the rate of heat
input to the coilCl by the heater H is such as to maintain
the average temperature of the coil Cl well above the
ambient air temperature but not greater than about 70 F.
whenever the ambient air temperature is less than the value
set for the heat augmenting mode (e.g., 32-38F.). In
practical terms, the rate of heater H input will be
relatively low so that an efficient heating of the coil Cl
is effected~ and minimal heat loss to ambient atmosphere
occurs.
Reference is now made to Figures 6, 7 and 8 of the
drawings which illustrates a slightly modified form of the
heat exchanger or heat-augmented heat pump of Figures 1
through 4, and the heat exchanger of Figures 7 and 8 is
generally designated by the reference numeral 110.
The heat e~changer 110 includes the housing 111 defined
by a front wall 112, a rear wall 113, end walls 11~, 115~
and a pair of bottom flanges 116 formed at lower ends of the
walls 112, 113. A top wall or cover 117 is preferably
~ ~73~
hinged (not shown) to an upper edge portion of the rear wall
113 so that ample access to the interior oE the housing lll
is provided from above when the cover 117 is in its open
position.
The housing 111 is separated into a pair of chamber
means or chambers 125, 126 by a vertical partition or wall
127 while a horizontal partition or wall 128 having a
central opening 129 separates the chamber 126 into an upper
chamber portion 130 and a lower chamber portion 131. The
construction of the housing 111 is essentially identical to
the construction of the housing 11, particularly the manner
in which both are partitioned to achieve high e~ficiency air
flow as well as increased noise damping characteristics.
Furthermore, all of the electrical components of the
electrical system of Figure 5 heretofore described are
located in the chamber 125 of the heat exchanger 110, just
as the same were located in the chamber 25 of the heat
exchanger lO.
As in the case of the heat exchanger lO, the major
components of the heat exchanger llO of the invention of
Figures 7 and 8 include compressor means 150, an "A-coil"
60~ and means 170 for providing a heat source to augment the
temperature of outside ambient air. In addition to the
latter-noted major components, the heat exchanger llO also
includes a blower ]80 and a reversing expansion valve 190
(Figure 6).
The outdoor "A-coil" 160 is fully illustrated in
Figures 6 through 8 of the drawings and includes two oEf-
the-shelf coils which are supported in a generally inverted
V-shaped configuration with each individual coil being
~873~
designated by the reference numerals 135 and 137. The
bottom end portions of the "A-coil" 160 rests upon an
annular condensation collecting pan 138 which includes a
central elongated opening 139 disposed adjacent the opening
l2.') oE the horizontal partition or wall 128 (Figure 8). The
left-hand side oE the condensation collecting pan 138, as
viewecl in Figure 8, is elevated slightly and held in the
elevated position by a bracket 120 resting atop the
horizontal partition or wall 128. Thus~ any condensation
which forms upon the coil 160 will collect in the
condensation collecting pan 138 and will flow under the
influence of gravity toward and into an outlet conduit or
pipe 121 brazed to an opening (unnumbered) in the bottom
wall (also unnumbered) of the condensation pan 138. A
transparent plastic pipe 122 is connected to the pipe 121
and passes outwardly of the wall 113 (Figure 7) through a
hole 123 therein. Thus, any condensation which collects in
the condensation pan 138 and flows to the pipe 121 will flow
therethrough and be discharged by the transparent plastic
tube 122 exterior of the wall 113.
The coils 135 and 137 include at respective upper end
portions inlets/outlets 135a, 135b and 135c and 137a, 137b
and 137c. Likewise, a lower end portion of each of the
coils 135, 137 includes respective inlets/outlets 135d,
135e, 135f and 137d, 137e, and 137f. The expression
"inlet/outlet" is utilized in the same fashion as in
conjunction with the heat exchanger 10. The inlets/outlets,
conduits or pipes 135a, 135b, 135c, 137a, 137b, and 137c are
connected to a common manifold 140 whereas the inlets/
outlets, conduits or pipes 135d, 135e, 135f, 137d~ 137e and
137f are connected to a generally tubular body 141 (Figures
9 and 10) defining an interlor reservoir 142. The openings
(unnumbered) of the conduits 135d, 135e, L35f, 137d, 137e
ancl l37E are positioned on identical horizontal level with
each other (Figure 9), and each is slightly above an opening
(unnumbered) of a liquid return line, pipe or conduit means
143 which serves as the cold liquid return of the heat
exchange medium or refrigerant from an indoor coil 149 of a
conventional construction during the heating mode of the
operation of the machine 110 with the circulation during the
heating mode being indicated by the unnumbered headed arrows
of ~igure 6. Thus, by virtue of the disposition of the
conduit means within the body 141, cold liquid which returns
to the reservoir 142 will flow equally into all of the
conduits 135d, 135e, 135f, 137d, 137e and 137f thus assuring
that each individual coil (unnumbered) of the two coils 135,
137 will receive an equal amount of the refrigerant or heat-
exchange medium during the operation of the exchanger 110.
Returning specifically to Figure 6 of the drawings, the
manifold 140 is in fluid communication with the expansion
valve 190 which can, of course, be shifted in its position
between the cooling and heating modes through a conventional
relay l91 operated to the circuit of Figure 5. In the
heating mode, the heated vapor phase of the heat~exchange
medium is transferred from the manifold 140 through the
regulating and expansion valve 190 into a conduit or conduit
means 192 and is then pumped by the compressor 150 to and
through a dryer 193, a conduit 194 an accumulator 195,
another conduit 196, the compressor 150 itself, another
23
~'73~
conduit 197, another dryer 19~, a conduit 200, the
regulator/expansion valve 190, a conduit or conduit means
201, the indoor heat exchanger 149 through which air is
blown to absorb heat from the refrigerant cooling the same
and returning it to its liquid phase which is returned via
the conduit 143 to the reservoir 142 and through the
conduits 135d, 135e, 135f, 137f, 137e, and 137d to the
individual coils 135, 137 whereat the cool liquid phase is
reheated by the burner 170, returned to its vapor phase, and
the heat mode repeated.
In further accordance with the present invention,
conduit means 210 are provided for preventing condensation
or condensate from freezing within the tube 122. The
conduit means 210 includes a singular tubular conduit having
an inlet end portion 211 (Figure 6) and an outlet end
portion 212 disposed in generally tangential relationship
within the conduit 201 with the end portion 211 being
disposed in generally opposing relationship to the flow of
fluid within the conduit 201 from an upstream point adjacent
the valve 190 toward a more remote downstream point at which
the end portion 212 is generally directed such that its
outflow is in the direction of the flow of the heat-exchange
medium through the conduit 201. The conduit or pipe 210 has
a bent or radius portion 215 thereby defining adjacent
portions 216, 217 which are in generally parallel
relationship and are received within the tube 122. The bent
end 215 is shown for convenience externally of the tube 122
but preferably the end 215 is housed entirely within the
tube 122 adjacent the end exposed outboard of the wall 113
24
3~
so that the bend portion 215 ancl the portions 216, 217
projecting outwardly from the wall 113 are protected by the
tube 122.
As was noted earlier, since the hot vapor phase from
the compressor 150 ls clirected into the conduit 201 from
rlght-to-left duri.ng the heating mode of operation of the
heat exchanger 110, as was heretofore described, a portion
of the vapor phase of the heat exchange medium or
refrigerant enters the end portion 211 of the conduit 210,
obviously heats the same, and runs the full length of the
conduit including a return path from the bend 215 with the
return being back into the conduit 201 from the outlet 212.
The heat radiating and conducting from the conduit 210
within the tube 122 thereby prevents condensation from
freezing and, therefore, any liquid (water/condensate) which
may form in the tray 138 will assuredly be withdrawn
therefrom and, therefore, excessive buildup of such frozen
condensation with the attendant loss in efficiency as it
might buildup vertically along the coils 135, 137 is
precluded.
Although in a preferred embodiment of the invention as
has been specifically illustrated and describecl herein, it
is to be understood that minor variations may be made in the
apparatus without departing from the spirit and scope of the
invention, as defined in the appended claims.
