FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
“REFRIGERATION DEVICE”
PANASONIC CORPORATION, a Japanese Corporation of 1006, Oaza Kadoma,
Kadoma-shi, Osaka 5718501, Japan;
The following specification particularly describes the invention and the manner in which
it is to be performed.
2
DESCRIPTION
REFRIGERATION DEVICE
5 TECHNICAL FIELD
[0001] The present invention relates to a refrigeration apparatus.
BACKGROUND ART
[0002] Conventionally, refrigeration apparatuses such as air conditioners, in which
10 chlorofluorocarbon or an alternative for chlorofluorocarbon is used as a refrigerant,
are widely used. However, these refrigerants are responsible for the problems such
as ozone depletion and global warming. In view of these, air conditioners have
been proposed in which water is used as a refrigerant having a very low impact on
the global environment. As an example of such an air conditioner, Patent
15 Literature 1 discloses an air conditioner designed specifically for cooling a room.
[0003] When water is used as a refrigerant, a large amount of refrigerant vapor
needs to be compressed at a high compression ratio. Accordingly, the air
conditioner disclosed in Patent Literature 1 includes two compressors, i.e., a
centrifugal compressor and a positive displacement compressor, and these
20 compressors are arranged in series so that a refrigerant vapor compressed by the
centrifugal compressor is further compressed by the positive displacement
compressor.
[0004] In addition, when water is used as a refrigerant, the temperature of the
refrigerant discharged from a compressor is high due to the physical properties of
25 water. Therefore, the durability of members constituting a high-pressure part of
an air conditioner decreases. In order to address this problem, it is effective to
dispose a vapor cooler between the upstream-side compressor and the
downstream-side compressor as in the air conditioner disclosed in Patent Literature
1, so as to temporarily lower the temperature of the refrigerant vapor in the course
30 of the compression process.
CITATION LIST
Patent Literature
[0005] Patent Literature 1: JP 2008-122012 A
35
SUMMARY OF INVENTION
Technical Problem
3
[0006] The air conditioner disclosed in Patent Literature 1 is designed specifically
for cooling a room, but it may be possible to use this air conditioner for heating a
room. However, in that case, heat released from the refrigerant vapor in the vapor
cooler results in heat loss, which reduces the heating capacity. This means that the
COP (coefficient of performance) of the air conditioner 5 decreases.
[0007] In view of the above circumstances, it is an object of the present invention to
improve the COP of a refrigeration apparatus in heating operation.
Solution to Problem
10 [0008] In order to achieve the above object, a first aspect of the present disclosure
provides a refrigeration apparatus including: a refrigerant circuit that allows a
refrigerant to circulate, the refrigerant circuit including an evaporator that retains
a refrigerant liquid and that evaporates the refrigerant liquid therein, a first
compressor that compresses a refrigerant vapor, a vapor cooler that cools the
15 refrigerant vapor, a second compressor that compresses the refrigerant vapor, and a
condenser that condenses the refrigerant vapor therein and that retains the
refrigerant liquid, wherein the evaporator, the first compressor, the vapor cooler, the
second compressor, and the condenser are connected in this order; a heat release
circuit that allows a heat medium to circulate between the condenser and a first
20 heat exchanger that releases heat to the atmosphere; and a heat absorption circuit
that allows a heat medium to circulate between the evaporator and a second heat
exchanger, wherein the vapor cooler is a heat exchanger that exchanges heat
between the refrigerant vapor compressed by the first compressor and the heat
medium flowing in the heat release circuit or the heat medium flowing in the heat
25 absorption circuit.
Advantageous Effects of Invention
[0009] According to the refrigeration apparatus described above, since heat is
released from the first heat exchanger to the atmosphere, heating can be performed.
30 In addition, the heat released from the refrigerant vapor in the vapor cooler can be
recovered by the heat medium. Therefore, the heat loss in heating operation is
significantly reduced. Thereby, the COP of the refrigeration apparatus can be
improved. Furthermore, according to the refrigeration apparatus described above,
a secondary cooling system for cooling the refrigerant vapor can be omitted. This
35 advantage can also be obtained when the refrigeration apparatus is used for cooling.
BRIEF DESCRIPTION OF DRAWINGS
4
[0010] FIG. 1 is a configuration diagram of an air conditioner according to a first
embodiment of the present invention.
FIG. 2 is a configuration diagram of an air conditioner of a modification of
the first embodiment.
FIG. 3 is a configuration diagram of an air conditioner 5 of another
modification of the first embodiment.
FIG. 4 is a configuration diagram of an air conditioner of still another
modification of the first embodiment.
FIG. 5 is a configuration diagram of an air conditioner according to a second
10 embodiment of the present invention.
FIG. 6 is a configuration diagram of an air conditioner of a modification of
the second embodiment.
FIG. 7 is a configuration diagram of an air conditioner of another
modification of the second embodiment.
15 FIG. 8 is a configuration diagram of an air conditioner according to a third
embodiment of the present invention.
FIG. 9 is a configuration diagram of an air conditioner of a modification of
the third embodiment.
FIG. 10 is a configuration diagram of an air conditioner of another
20 modification of the third embodiment.
FIG. 11 is a configuration diagram of an air conditioner of still another
modification of the third embodiment.
FIG. 12 is a configuration diagram of an air conditioner according to a
fourth embodiment of the present invention.
25 FIG. 13 is a configuration diagram of an air conditioner of a modification of
the fourth embodiment.
FIG. 14 is a configuration diagram of an air conditioner of another
modification of the fourth embodiment.
FIG. 15 is a configuration diagram of an air conditioner of still another
30 modification of the fourth embodiment.
FIG. 16 is a configuration diagram of an air conditioner of still another
modification of the fourth embodiment.
DESCRIPTION OF EMBODIMENTS
35 [0011] A second aspect provides the refrigeration apparatus as set forth in the first
aspect, wherein the heat medium circulating in the heat release circuit may be the
refrigerant liquid retained in the condenser. The heat release circuit may include a
5
heat release side feed path that feeds the refrigerant liquid from the condenser to
the first heat exchanger and that is provided with a pump, and a heat release side
return path that returns the refrigerant liquid from the first heat exchanger to the
condenser. The vapor cooler may be disposed on the heat release side feed path.
Since the vapor cooler is disposed on the heat release side feed path, 5 it is possible to
raise the temperature of the refrigerant liquid flowing into the first heat exchanger
so as to increase the temperature difference between a medium to be heated (for
example, indoor air) and the refrigerant liquid flowing into the first heat exchanger.
Thus, the heating capacity of the refrigeration apparatus can be enhanced.
10 [0012] A third aspect provides the refrigeration apparatus as set forth in the second
aspect, wherein the heat medium circulating in the heat absorption circuit may be
the refrigerant liquid retained in the evaporator. The heat absorption circuit may
include a heat absorption side feed path that feeds the refrigerant liquid from the
evaporator to the second heat exchanger and that is provided with a pump, and a
15 heat absorption side return path that returns the refrigerant liquid from the second
heat exchanger to the evaporator. The refrigeration apparatus may further include
an injection passage that injects the refrigerant liquid pumped from the pump in
the heat absorption side feed path into a section of the refrigerant circuit between
the vapor cooler and the second compressor. In the case where the injection
20 passage is thus provided, the temperature of the refrigerant to be drawn into the
second compressor can significantly lowered. Therefore, the reliability of the
refrigeration apparatus, in particular, the reliability of the second compressor can
be further improved.
[0013] A fourth aspect provides the refrigeration apparatus as set forth in the
25 second or the third aspect, wherein the heat release side feed path may be provided
with a bypass passage that bypasses the vapor cooler. The bypass passage may be
provided with a flow rate regulating mechanism. In the case where the bypass
passage having the flow rate regulating mechanism is provided, the amount of heat
released from the refrigerant vapor between the first compressor and the second
30 compressor can be optimally controlled.
[0014] A fifth aspect provides the refrigeration apparatus as set forth in the first
aspect, wherein the heat medium circulating in the heat absorption circuit may be
the refrigerant liquid retained in the evaporator. The heat absorption circuit may
include a heat absorption side feed path that feeds the refrigerant liquid from the
35 evaporator to the second heat exchanger and that is provided with a pump, and a
heat absorption side return path that returns the refrigerant liquid from the second
heat exchanger to the evaporator. The vapor cooler may be disposed on the heat
6
absorption side feed path. According to the fifth aspect, in the vapor cooler, the
refrigerant vapor can be cooled using the lower temperature refrigerant liquid.
Therefore, the temperature of the refrigerant to be drawn into the second
compressor can be further lowered.
[0015] A sixth aspect provides the refrigeration apparatus as set 5 forth in the fifth
aspect, which may further include an injection passage that injects the refrigerant
liquid pumped from the pump in the heat absorption side feed path into a section of
the refrigerant circuit between the vapor cooler and the second compressor. In the
case where the injection passage is thus provided, the temperature of the
10 refrigerant to be drawn into the second compressor can be lowered. Therefore, the
reliability of the refrigeration apparatus, in particular, the reliability of the second
compressor can be further improved.
[0016] A seventh aspect provides the refrigeration apparatus as set forth in the
fifth or the sixth aspect, wherein the heat absorption side feed path may be provided
15 with a bypass passage that bypasses the vapor cooler. The bypass passage may be
provided with a flow rate regulating mechanism. In the case where the bypass
passage having the flow rate regulating mechanism is provided, the amount of heat
released from the refrigerant vapor between the first compressor and the second
compressor can be optimally controlled.
20 [0017] A eighth aspect provides the refrigeration apparatus as set forth in any one
of the fifth to seventh aspects, wherein the heat medium circulating in the heat
release circuit may be the refrigerant liquid retained in the condenser. The heat
release circuit may include a heat release side feed path that feeds the refrigerant
liquid from the condenser to the first heat exchanger and that is provided with a
25 pump, and a heat release side return path that returns the refrigerant liquid from
the first heat exchanger to the condenser. This configuration eliminates the need
for a heat medium other than the refrigerant liquid. Therefore, the refrigeration
apparatus can be simplified.
[0018] A ninth aspect provides the refrigeration apparatus as set forth in any one
30 of the first to eighth aspects, wherein the second heat exchanger may be a heat
exchanger that absorbs heat from the atmosphere. In this case, the second heat
exchanger can be disposed outdoors.
[0019] A tenth aspect of the present disclosure provides a refrigeration apparatus
including: a refrigerant circuit that allows a refrigerant to circulate, the refrigerant
35 circuit including an evaporator that retains a refrigerant liquid and that evaporates
the refrigerant liquid therein, a first compressor that compresses a refrigerant vapor,
a vapor cooler that cools the refrigerant vapor, a second compressor that compresses
7
the refrigerant vapor, and a condenser that condenses the refrigerant vapor therein
and that retains the refrigerant liquid, wherein the evaporator, the first compressor,
the vapor cooler, the second compressor, and the condenser are connected in this
order; a heat release circuit that allows a heat medium to circulate between the
condenser and a first heat exchanger that releases heat to indoor 5 air; and a heat
absorption circuit that allows a heat medium to circulate between the evaporator
and a second heat exchanger that absorbs heat from outdoor air, wherein the vapor
cooler is a heat exchanger that exchanges heat between the refrigerant vapor
compressed by the first compressor and air, and is disposed indoors or is disposed so
10 as to heat the air to be supplied to the second heat exchanger.
[0020] According to the refrigeration apparatus described above, since heat is
released from the first heat exchanger to the indoor air, heating can be performed.
In addition, the heat released from the refrigerant vapor in the vapor cooler can be
used for heating or recovered by the heat medium. Therefore, the heat loss in
15 heating operation is significantly reduced. Thereby, the COP of the refrigeration
apparatus can be improved.
[0021] An eleventh aspect provides the refrigeration apparatus as set forth in the
tenth aspect, which may further include an indoor fan that supplies the indoor air to
the first heat exchanger. The vapor cooler may be disposed in such a manner that
20 a wind generated by the indoor fan passes through the first heat exchanger and
then through the vapor cooler. In the tenth aspect, the vapor cooler is disposed on
the leeward side of the first heat exchanger. Therefore, the size and layout of the
vapor cooler can be arbitrarily determined.
[0022] A twelfth aspect provides the refrigeration apparatus as set forth in the
25 tenth or the eleventh aspect, wherein the heat medium circulating in the heat
absorption circuit may be the refrigerant liquid retained in the evaporator. The
heat absorption circuit may include a heat absorption side feed path that feeds the
refrigerant liquid from the evaporator to the second heat exchanger and that is
provided with a pump, and a heat absorption side return path that returns the
30 refrigerant liquid from the second heat exchanger to the evaporator. The
refrigeration apparatus may further include an injection passage that injects the
refrigerant liquid pumped from the pump in the heat absorption side feed path into
a section of the refrigerant circuit between the vapor cooler and the second
compressor. In the case where the injection passage is thus provided, the
35 temperature of the refrigerant to be drawn into the second compressor can be
significantly lowered. Therefore, the reliability of the refrigeration apparatus, in
particular, the reliability of the second compressor can be further improved.
8
[0023] A thirteenth aspect provides the refrigeration apparatus as set forth in any
one of the tenth to twelfth aspects, wherein the refrigerant circuit may be provided
with a bypass passage that bypasses the vapor cooler. The bypass passage may be
provided with a flow rate regulating mechanism. In the case where the bypass
passage having the flow rate regulating mechanism is provided, 5 the amount of heat
released from the refrigerant vapor between the first compressor and the second
compressor can be optimally controlled.
[0024] A fourteenth aspect provides the refrigeration apparatus as set forth in any
one of the tenth to thirteenth aspects, wherein the heat medium circulating in the
10 heat release circuit may be the refrigerant liquid retained in the condenser. The
heat release circuit may include a heat release side feed path that feeds the
refrigerant liquid from the condenser to the first heat exchanger and that is
provided with a pump, and a heat release side return path that returns the
refrigerant liquid from the first heat exchanger to the condenser. This
15 configuration eliminates the need for a heat medium other than the refrigerant
liquid. Therefore, the refrigeration apparatus can be simplified.
[0025] Hereinafter, embodiments of the present invention are described in detail
based on the drawings.
[0026] (First Embodiment)
20 FIG. 1 shows an air conditioner 1A according to the first embodiment of the
present invention. This air conditioner 1A includes: a refrigerant circuit 2 that
allows a refrigerant to circulate; a heat release circuit 4 that allows a heat medium
to circulate to cool the refrigerant; and a heat absorption circuit 6 that allows a heat
medium to circulate to heat the refrigerant.
25 [0027] In the present embodiment, the heat release circuit 4 and the heat
absorption circuit 6 are each a circuit that merges into the refrigerant circuit 2 to
bring the heat medium into direct contact with the refrigerant, and the refrigerant
circuit 2, the heat release circuit 4, and the heat absorption circuit 6 are filled with
the same refrigerant. That is, a portion of the refrigerant is used as the heat
30 medium. This refrigerant is a refrigerant whose saturated vapor pressure is a
negative pressure at ordinary temperature, for example, a refrigerant whose main
component is water, alcohol or ether, and the pressure in each of the refrigerant
circuit 2, the heat release circuit 4, and the heat absorption circuit 6 is a negative
pressure lower than the atmospheric pressure. A portion of a refrigerant liquid
35 resulting from liquefaction of the refrigerant in the refrigerant circuit 2 circulates
through the heat release circuit 4 and the heat absorption circuit 6. A refrigerant
containing water as a main component and further containing ethylene glycol,
9
Nybrine, an inorganic salt, or the like in an amount of 10 to 40% by mass can also
be used as the refrigerant for the reasons such as prevention of freezing, etc. The
term “main component” refers to a component whose content is the highest in mass.
[0028] The refrigerant circuit 2 includes an evaporator 25, a first compressor 21, a
vapor cooler 3, a second compressor 22, a condenser 23, and an 5 expansion valve 24,
and these devices are connected in this order by flow paths. That is, the
refrigerant circulating in the refrigerant circuit 2 passes through the evaporator 25,
the first compressor 21, the vapor cooler 3, the second compressor 22, the condenser
23, and the expansion valve 24 in this order.
10 [0029] The evaporator 25 is a heat exchanger that retains the refrigerant liquid
and allows this retained refrigerant liquid to be heated and evaporated therein by
the refrigerant liquid circulating in the heat absorption circuit 6, or a heat
exchanger that directly evaporates therein the refrigerant liquid that has been
heated while circulating in the heat absorption circuit 6. In the present
15 embodiment, the internal space of the evaporator 25 forms a flow path common to
the refrigerant circuit 2 and the heat absorption circuit 6. Therefore, the
refrigerant liquid in the evaporator 25 comes into direct contact with the refrigerant
liquid circulating in the heat absorption circuit 6 as described above, and as a result,
the heated refrigerant liquid and the refrigerant liquid serving as a heat medium
20 for heating are mixed together to have almost the same temperature. In other
words, a portion of the refrigerant liquid in the evaporator 25 is heated by a second
heat exchanger 7 described later and used as a heat source for heating the
saturated refrigerant liquid.
[0030] The refrigerant vapor is compressed in two stages by the first compressor 21
25 and the second compressor 22. The first compressor 21 and the second compressor
22 may each be a positive displacement compressor or a centrifugal compressor.
The compression ratios of the first compressor and the second compressor can be
determined as appropriate, and may have the same value. The temperature of the
refrigerant vapor discharged from the first compressor 21 is, for example, 140°C,
30 and the temperature of the refrigerant vapor discharged from the second
compressor 22 is, for example, 170°C.
[0031] The vapor cooler 3 cools the refrigerant vapor discharged from the first
compressor 21 before the refrigerant vapor is drawn into the second compressor 22.
The vapor cooler 3 of the present embodiment is a heat exchanger that exchanges
35 heat between the refrigerant vapor compressed by the first compressor 21 and the
refrigerant liquid flowing in the heat release circuit 4. As the vapor cooler 3, for
example, a shell-and-tube heat exchanger can be used. In this case, preferably, the
10
refrigerant liquid flows in a tube and the refrigerant vapor flows in a shell
surrounding the tube.
[0032] The condenser 23 is a heat exchanger that allows the refrigerant vapor
discharged from the second compressor 22 to be cooled and condensed therein by the
refrigerant liquid circulating in the heat release circuit 4 5 and that retains the
refrigerant liquid resulting from the condensation. In the present embodiment, the
internal space of the condenser 23 forms a flow path common to the refrigerant
circuit 2 and the heat release circuit 4. Therefore, the refrigerant vapor discharged
from the second compressor 22 comes into direct contact with the refrigerant liquid
10 circulating in the heat release circuit 4 as described above, and as a result, the
refrigerant liquid resulting from the condensation and the refrigerant liquid serving
as a heat medium for cooling are mixed together to have almost the same
temperature. In other words, a portion of the refrigerant liquid resulting from the
condensation is supercooled in the first heat exchanger 5 described later and used
15 as a heat source for cooling the superheated refrigerant vapor. The temperature of
the refrigerant liquid resulting from the condensation is, for example 45°C.
[0033] The expansion valve 24 is one example of a pressure-reducing mechanism
that reduces the pressure of the refrigerant liquid resulting from the condensation.
The temperature of the pressure-reduced refrigerant liquid is, for example 5°C.
20 The expansion valve 24 need not be provided in the refrigerant circuit 2, and, for
example, a configuration in which the level of the refrigerant liquid in the
evaporator 25 is higher than the level of the refrigerant liquid in the condenser 23
may be employed as a pressure-reducing mechanism.
[0034] The heat release circuit 4 allows the refrigerant liquid retained in the
25 condenser 23 to circulate between the first heat exchanger 5 for releasing heat to
the atmosphere and the condenser 23. The first heat exchanger 5 is disposed
indoors and heats the indoor air supplied by an air blower 51. Thus, an indoor
space is heated.
[0035] More specifically, the heat release circuit 4 includes a heat release side feed
30 path 41 that feeds the refrigerant liquid from the condenser 23 to the first heat
exchanger 5, and a heat release side return path 42 that returns the refrigerant
liquid from the first heat exchanger 5 to the condenser 23. The heat release side
feed path 41 is provided with a pump 43 that pumps the refrigerant liquid toward
the first heat exchanger 5. In the heat release side feed path 41, the
35 above-mentioned vapor cooler 3 is disposed downstream from the pump 43. The
pump 43 is disposed at such a position that the height from the suction port of the
pump to the level of the refrigerant liquid in the condenser 23 is larger than a
11
required net positive suction head (required NPSH).
[0036] Preferably, the upstream end of the heat release side feed path 41 is
connected to the lower part of the condenser 23. Preferably, a mechanism for
dispersing the refrigerant liquid, such as a spray nozzle, is provided at the
downstream end of the heat release side 5 return path 42.
[0037] The heat absorption circuit 6 allows the refrigerant liquid retained in the
evaporator 25 to circulate between the second heat exchanger 7 that absorbs heat
from the atmosphere and the evaporator 25. The second heat exchanger 7 is
disposed outdoors and cools the outdoor air supplied by an air blower 71.
10 [0038] More specifically, the heat absorption circuit 6 includes a heat absorption
side feed path 61 that feeds the refrigerant liquid from the evaporator 25 to the
second heat exchanger 7, and a heat absorption side return path 62 that returns the
refrigerant liquid from the second heat exchanger 7 to the evaporator 25. The heat
absorption side feed path 61 is provided with a pump 63 that pumps the refrigerant
15 liquid toward the second heat exchanger 7. The pump 63 is disposed at such a
position that the height from the suction port of the pump to the level of the
refrigerant liquid in the evaporator 25 is larger than a required net positive suction
head (required NPSH).
[0039] Preferably, the upstream end of the heat absorption side feed path 61 is
20 connected to the lower portion of the evaporator 25. Preferably, the downstream
end of the heat absorption side return path 62 is connected to the middle part of the
evaporator 25.
[0040] Next, how the air conditioner 1A works is described.
[0041] The refrigerant vapor compressed by the first compressor 21 is cooled in the
25 vapor cooler 3 by the refrigerant liquid resulting from the condensation, and then
drawn into the second compressor 22. The refrigerant vapor further compressed by
the second compressor 22 is condensed in the condenser 23 by heat exchange with
the refrigerant liquid supercooled in the first heat exchanger 5. A portion of the
refrigerant liquid resulting from the condensation in the condenser 23 is fed to the
30 vapor cooler 3 by the pump 43, exchanges heat with the refrigerant vapor
compressed by the first compressor, and then is pumped to the first heat exchanger
5. The refrigerant liquid pumped to the first heat exchanger 5 releases heat to the
indoor air in the first heat exchanger 5 and then returns to the condenser 23.
[0042] The remaining portion of the refrigerant liquid resulting from the
35 condensation in the condenser 23 is introduced into the evaporator 25 via the
expansion valve 24. A portion of the refrigerant liquid in the evaporator 25 is
pumped by the pump 63 to the second heat exchanger 7, absorbs heat from the
12
outdoor air in the second heat exchanger 7, and then returns to the evaporator 25.
The refrigerant liquid in the evaporator 25 is evaporated by being boiled under a
reduced pressure, and the refrigerant vapor resulting from the evaporation is drawn
into the first compressor 21.
[0043] In the air conditioner 1A of the present embodiment, 5 the heat released from
the refrigerant vapor in the vapor cooler 3 can be recovered by the refrigerant liquid
serving as a heat medium for heating the indoor air. Therefore, the heat loss in the
heating operation is significantly reduced. Thereby, the COP of the air conditioner
1A can be improved.
10 [0044] In addition, since the refrigerant vapor is cooled in the vapor cooler 3 before
the refrigerant vapor is drawn into the second compressor 22, the amount of scale
deposited on the second compressor 22 can be reduced even if the refrigerant
contains impurities. Thereby, the reliability of the second compressor 22 can be
improved.
15 [0045] Furthermore, in the present embodiment, since the vapor cooler 3 is
disposed on the heat release side feed path 41, the temperature of the refrigerant
liquid flowing into the first heat exchanger 5 can be raised to increase the
temperature difference between the indoor air and the heat medium for heating the
indoor air. Thus, the heating capacity of the air conditioner 1A can be enhanced.
20 [0046]
Various modifications can be made to the air conditioner 1A of the
previously-described embodiment.
[0047] For example, as shown in FIG. 2, the air conditioner 1A may include an
injection passage 81 that injects the refrigerant liquid pumped from the pump 63 in
25 the heat absorption side feed path 61 into a section of the refrigerant circuit 2
between the vapor cooler 3 and the second compressor 22. In this case, since the
injection is performed by means of pumping of the pump 63, the upstream end of
the injection passage 81 is connected to a position downstream from the pump 63 in
the heat absorption side feed path 61. The injection passage 81 is provided with an
30 injection valve 82 for regulating the injection flow rate.
[0048] A portion of the refrigerant liquid withdrawn from the evaporator 25 does
not flow into the second heat exchanger 7 but is injected into the refrigerant circuit
2 between the vapor cooler 3 and the second compressor 22 through the injection
passage 81. The opening degree of the injection valve 82 is controlled, for example,
35 based on the temperature of the refrigerant discharged from the second compressor
22. That is, when the temperature of the refrigerant discharged from the second
compressor 22 is higher than a predetermined value, control for increasing the
13
opening degree of the injection valve 82 is performed.
[0049] In the case where the injection passage 81 is thus provided, the temperature
of the refrigerant to be drawn into the second compressor 22 can be significantly
lowered. Therefore, the reliability of the air conditioner 1A, in particular, the
reliability of the second compressor 22 can 5 be further improved.
[0050] As another modification, as shown in FIG. 2, the heat release side feed path
41 may be provided with a bypass passage 83 that bypasses the vapor cooler 3.
The bypass passage 83 is branched from the heat release side feed path 41 at a
position between the pump 43 and the vapor cooler 3 and is connected to the heat
10 release side feed path 41 at a position downstream from the vapor cooler 3. The
bypass passage 83 is provided with a flow rate regulating valve (a flow rate
regulating mechanism) 84.
[0051] In the case where the bypass passage 83 having the flow rate regulating
valve 84 is thus provided, the amount of heat released from the refrigerant vapor
15 between the first compressor 21 and the second compressor 22 can be optimally
controlled. In the case where a less amount of heat released from the refrigerant
vapor is enough for the operation of the air conditioner 1A under certain conditions,
the refrigerant liquid is allowed to flow preferentially in the bypass passage 83 so as
to perform control of reducing the amount of released heat. Thus, the COP and
20 comfort level of the air conditioner 1A are improved.
[0052] For example, the flow rate regulating valve 84 is controlled to move to a full
open position for a predetermined period of time (for example, 3 minutes) from the
startup of the air conditioner 1A. Thereby, the amount of heat released from the
refrigerant vapor discharged from the first compressor 21 is reduced, which makes
25 it possible to accelerate the rate of increase in the temperature of the refrigerant
vapor discharged from the second compressor 22. As a result, the startup time of
the air conditioner 1A can be reduced, and thus the comfort level in the heating
operation can be improved. After the elapse of the predetermined period of time,
the flow rate regulating valve 84 is controlled to move to a close position to reduce
30 the bypass flow rate gradually. Thus, the reliability of the second compressor 22 is
ensured.
[0053] As shown in FIG. 3, the air conditioner 1A according to still another
modification may include a third compressor 33 and a second vapor cooler 13. In
the refrigerant circuit 2, the evaporator 25, the first compressor 21, the vapor cooler
35 3 (a first vapor cooler), the second compressor 22, the second vapor cooler 13, the
third compressor 33, the condenser 23, and the expansion valve 24 are connected in
this order. According to the third compressor 33, efficient heating operation can be
14
performed when the outdoor air temperature is low and efficient cooling operation
can be performed when the outdoor air temperature is high.
[0054] The third compressor 33 compresses the refrigerant compressed by the
second compressor 22. The third compressor 33 may be a positive displacement
compressor or a centrifugal compressor. The second vapor 5 cooler 13 cools the
refrigerant vapor discharged from the second compressor 22 before the refrigerant
vapor is drawn into the third compressor 33. The second vapor cooler 13 is a heat
exchanger that exchanges heat between the refrigerant vapor compressed by the
second compressor 22 and the refrigerant liquid flowing in the heat release circuit 4.
10 As the second vapor cooler 13, for example, a shell-and-tube heat exchanger can be
used, like the vapor cooler 3. In this case, preferably, the refrigerant liquid flows in
a tube and the refrigerant vapor flows in a shell surrounding the tube.
[0055] The second vapor cooler 13 is disposed between the first vapor cooler 3 and
the first heat exchanger 5 in the heat release side feed path 41. That is, the
15 refrigerant liquid can be heated in two stages by the first vapor cooler 3 and the
second vapor cooler 13. Therefore, the heating capacity of the air conditioner 1A
can be further enhanced.
[0056] As shown in FIG. 4, in still another modification, the air conditioner 1A
includes a first circulation path 4a, a second circulation path 6a, a first switching
20 valve 27, and a second switching valve 28. The first circulation path 4a is a path
that allows the refrigerant liquid retained in the condenser 23 to circulate via the
first heat exchanger 5. The first circulation path 4a corresponds to the heat release
circuit 4. In the first circulation path 4a, the pump 43 (a first pump) is provided at
a position upstream from the first heat exchanger 5. The second circulation path
25 6a is a path that allows the refrigerant liquid retained in the evaporator 25 to
circulate via the second heat exchanger 7. The second circulation path 6a
corresponds to the heat absorption circuit 6. In the second circulation path 6a, the
pump 63 (a second pump) is provided at a position upstream from the second heat
exchanger 7. The first switching valve 27 is provided in the first circulation path
30 4a and the second circulation path 6a. The first switching valve 27 is switched
between a first state and a second state. In the first state, the refrigerant liquid
pumped from the first pump 43 is directed to the first heat exchanger 5 and the
refrigerant liquid pumped from the second pump 63 is directed to the second heat
exchanger 7. In the second state, the refrigerant liquid pumped from the first
35 pump 43 is directed to the second heat exchanger 7 and the refrigerant liquid
pumped from the second pump 63 is directed to the first heat exchanger 5. The
second switching valve 28 also is provided in the first circulation path 4a and the
15
second circulation path 6a. The second switching valve 28 is switched between a
first state and a second state. In the first state, the refrigerant liquid flowing from
the first heat exchanger 5 is directed to the condenser 23 and the refrigerant liquid
flowing from the second heat exchanger 7 is directed to the evaporator 25. In the
second state, the refrigerant liquid flowing from the first 5 heat exchanger 5 is
directed to the evaporator 25 and the refrigerant liquid flowing from the second heat
exchanger 7 is directed to the condenser 23. The use of the first switching valve 27
and the second switching valve 28 makes it possible to switch between cooling
operation and heating operation.
10 [0057] A section of the first circulation path 4a between the first pump 43 and the
first heat exchanger 5 intersects with a section of the second circulation path 6a
between the second pump 63 and the second heat exchanger 7, and the first
switching valve 27 is provided at the intersection. Furthermore, a section of the
first circulation path 4a between the first heat exchanger 5 and the condenser 23
15 intersects with a section of the second circulation path 6a between the second heat
exchanger 7 and the evaporator 25, and the second switching valve 28 is provided at
the intersection.
[0058] More specifically, the first circulation path 4a includes: a first flow path 41
connecting the condenser 23 and the first switching valve 27 and provided with the
20 first pump 43 and the vapor cooler 3; a second flow path 45 connecting the first
switching valve 27 and the first heat exchanger 5; a third flow path 46 connecting
the first heat exchanger 5 and the second switching valve 28; and a fourth flow path
47 connecting the second switching valve 28 and the condenser 23. The first flow
path 44 and the second flow path 45 correspond to the heat release side feed path 41.
25 The third flow path 46 and the fourth flow path 47 correspond to the heat release
side return path 42.
[0059] Likewise, the second circulation path 6a includes: a first flow path 64
connecting the evaporator 25 and the first switching valve 27 and provided with the
second pump 63; a second flow path 65 connecting the first switching valve 27 and
30 the second heat exchanger 7; a third flow path 66 connecting the second heat
exchanger 7 and the second switching valve 28; and a fourth flow path 67
connecting the second switching valve 28 and the evaporator 25. The first flow
path 64 and the second flow path 65 correspond to the heat absorption side feed
path 61. The third flow path 66 and the fourth flow path 67 correspond to the heat
35 absorption side return path 62. The vapor cooler 3 may be disposed on the second
circulation path 6a, as described later.
[0060] As the first switching valve 27, a four-way valve may be used, or a plurality
16
of three-way valves may be used. The same applies to the second switching valve
28.
[0061] (Second Embodiment)
FIG. 5 shows an air conditioner 1B according to the second embodiment of
the present invention. In the second to fourth embodiments, 5 the same components
as those in the first embodiment are denoted by the same reference numerals, and
the description thereof is partially omitted.
[0062] In the present embodiment, the vapor cooler 3 is not disposed on the heat
release circuit 4 but on the heat absorption circuit 6. That is, the vapor cooler 3 of
10 the present embodiment is a heat exchanger that exchanges heat between the
refrigerant vapor compressed by the first compressor 21 and the refrigerant liquid
flowing in the heat absorption circuit 6. More specifically, the vapor cooler 3 is
disposed downstream from the pump 63 in the heat absorption side feed path 61.
[0063] In the present embodiment, since the refrigerant vapor can be cooled using
15 the refrigerant liquid having a lower temperature than that in the first embodiment,
the temperature of the refrigerant to be drawn into the second compressor 22 can be
further lowered. Therefore, the air conditioner 1B of the present embodiment is
particularly useful when the temperature of the refrigerant discharged from the
second compressor 22 becomes higher, for example, when the air conditioner 1B is
20 used in a cold climate area. In addition to this effect, the same effects as those of
the first embodiment can be obtained.
[0064]
Various modifications can be made to the air conditioner 1B of the
previously-described embodiment.
25 [0065] For example, as shown in FIG. 6, the air conditioner 1B may include an
injection passage 91 that injects the refrigerant liquid pumped from the pump 63 in
the heat absorption side feed path 61 into a section of the refrigerant circuit 2
between the vapor cooler 3 and the second compressor 22. In this case, the
injection is performed by means of pumping of the pump 63, as in the modification
30 of the first embodiment. In the example shown in FIG. 6, the upstream end of the
injection passage 91 is connected to a position downstream from the vapor cooler 3
in the heat absorption side feed path 61. The injection passage 91 is provided with
an injection valve 92 for regulating the injection flow rate.
[0066] In the case where the injection passage 91 is thus provided, the temperature
35 of the refrigerant to be drawn into the second compressor 22 can be lowered, as in
the modification of the first embodiment. Therefore, the reliability of the air
conditioner 1B, in particular, the reliability of the second compressor 22 can be
17
further improved. Needless to say, the same effects can be obtained even if the
upstream end of the injection passage 91 is connected to a position upstream from
the vapor cooler 3, not to a position downstream from the vapor cooler 3, in the heat
absorption side feed path 61.
[0067] As another modification, as shown in FIG. 6, the heat 5 absorption side feed
path 61 may be provided with a bypass passage 93 that bypasses the vapor cooler 3.
The bypass passage 93 is branched from the heat absorption side feed path 61 at a
position between the pump 63 and the vapor cooler 3 and is connected to the heat
absorption side feed path 61 at a position downstream from the vapor cooler 3. The
10 bypass passage 93 is provided with a flow rate regulating valve (a flow rate
regulating mechanism) 94.
[0068] In the case where the bypass passage 93 having the flow rate regulating
valve 94 is thus provided, the amount of heat released from the refrigerant vapor
between the first compressor 21 and the second compressor 22 can be optimally
15 controlled, as in the modification of the first embodiment. In the case where a less
amount of heat released from the refrigerant vapor is enough for the operation of
the air conditioner 1B under certain conditions, the refrigerant liquid is allowed to
flow preferentially in the bypass passage 93 so as to perform control of reducing the
amount of released heat. Thus, the COP and comfort level of the air conditioner 1B
20 are improved.
[0069] For example, the flow rate regulating valve 94 is controlled to move to a full
open position for a predetermined period of time (for example, 3 minutes) from the
startup of the air conditioner 1B. Thereby, the amount of heat released from the
refrigerant vapor discharged from the first compressor 21 is reduced, which makes
25 it possible to accelerate the rate of increase in the temperature of the refrigerant
vapor discharged from the second compressor 22. As a result, the startup time of
the air conditioner 1B can be reduced, and thus the comfort level in the heating
operation can be improved. After the elapse of the predetermined period of time,
the flow rate regulating valve 94 is controlled to move to a close position to reduce
30 the bypass flow rate gradually. Thus, the reliability of the second compressor 22 is
ensured.
[0070] In still another modification, as shown in FIG. 7, the air conditioner 1B may
include a third compressor 33 and a second vapor cooler 13. The second vapor
cooler 13 cools the refrigerant vapor discharged from the second compressor 22
35 before the refrigerant vapor is drawn into the third compressor 33. The second
vapor cooler 13 is a heat exchanger that exchanges heat between the refrigerant
vapor compressed by the second compressor 22 and the refrigerant liquid flowing in
18
the heat absorption circuit 6. More specifically, the second vapor cooler 13 is
disposed between the first vapor cooler 3 and the second heat exchanger 7 in the
heat absorption feed path 61. This configuration makes it possible to efficiently
apply heat to the refrigerant liquid flowing in the heat absorption circuit 6.
[0071] 5 (Third Embodiment)
FIG. 8 shows an air conditioner 1C according to the third embodiment of the
present invention. This air conditioner 1C includes the refrigerant circuit 2, the
heat release circuit 4, and the heat absorption circuit 6. The structures and
functions of these circuits are as described in the first embodiment. A vapor cooler
10 8 is disposed on the refrigerant circuit 4.
[0072] The vapor cooler 8 is a heat exchanger that exchanges heat between the
refrigerant vapor compressed by the first compressor 21 and air, and cools the
refrigerant vapor discharged from the first compressor 21 before the refrigerant
vapor is drawn into the second compressor 22. In the present embodiment, the
15 vapor cooler 8 is disposed indoors. As the vapor cooler 8, for example, a
fin-and-tube heat exchanger can be used.
[0073] In the present embodiment, the above-mentioned vapor cooler 8 is disposed
in such a manner that a wind generated by an air blower 51 (an indoor fan 51)
passes through the first heat exchanger 5 and then through this vapor cooler 8. In
20 other words, the first heat exchanger 5 and the vapor cooler 8 are arranged side by
side in the direction of the air flow by the indoor fan 51, and the vapor cooler 8 is
located on the leeward side of the first heat exchanger 5.
[0074] Next, how the air conditioner 1C works is described.
[0075] The refrigerant vapor compressed by the first compressor 21 releases heat to
25 the indoor air in the vapor cooler 8, and then is drawn into the second compressor
22. The refrigerant vapor further compressed by the second compressor 22 is
condensed in the condenser 23 by heat exchange with the refrigerant liquid
supercooled in the first heat exchanger 5. A portion of the refrigerant liquid
resulting from the condensation in the condenser 23 is pumped to the first heat
30 exchanger 5 by the pump 43. The refrigerant liquid pumped to the first heat
exchanger 5 releases heat to the indoor air in the first heat exchanger 5 and then
returns to the condenser 23.
[0076] The remaining portion of the refrigerant liquid resulting from the
condensation in the condenser 23 is introduced into the evaporator 25 via the
35 expansion valve 24. A portion of the refrigerant liquid in the evaporator 25 is
pumped by the pump 63 to the second heat exchanger 7, absorbs heat from the
outdoor air in the second heat exchanger 7, and then returns to the evaporator 25.
19
The refrigerant liquid in the evaporator 25 is evaporated by being boiled under a
reduced pressure, and the refrigerant vapor resulting from the evaporation is drawn
into the first compressor 21.
[0077] In the air conditioner 1C of the present embodiment, the heat released from
the refrigerant vapor in the vapor cooler 8 can be used for 5 heating operation.
Therefore, the heat loss in the heating operation is significantly reduced. Thereby,
the COP of the air conditioner 1C can be improved.
[0078] The vapor cooler 8 need not necessarily be disposed on the leeward side of
the first heat exchanger 5, and for example, it may be disposed on the windward
10 side of the first heat exchanger 5. However, in this case, the temperature of the air
supplied to the first heat exchanger 5 rises. Therefore, some measures need to be
taken. For example, the vapor cooler 8 needs to be disposed in an area near the
refrigerant liquid outlet of the first heat exchanger 5. In contrast, in the present
embodiment, the vapor cooler 8 is disposed on the leeward side of the first heat
15 exchanger 5. Therefore, the size and layout of the vapor cooler 8 can be arbitrarily
determined.
[0079] Even if the vapor cooler 8 is not disposed near the first heat exchanger 5,
the heat released from the refrigerant vapor in the vapor cooler 8 can be used for
heating operation as long as the vapor cooler 8 is disposed indoors.
20 [0080]
Various modifications can be made to the air conditioner 1C of the
previously-described embodiment.
[0081] For example, as shown in FIG. 9, the air conditioner 1C may include an
injection passage 81 that injects the refrigerant liquid pumped from the pump 63 in
25 the heat absorption side feed path 61 into a section of the refrigerant circuit 2
between the vapor cooler 8 and the second compressor 22. In this case, since the
injection is performed by means of pumping of the pump 63, the upstream end of
the injection passage 81 is connected to a position downstream from the pump 63 in
the heat absorption feed path 61. The injection passage 81 is provided with an
30 injection valve 82 for regulating the injection flow rate.
[0082] A portion of the refrigerant liquid withdrawn from the evaporator 25 does
not flow into the second heat exchanger 7 but is injected into the refrigerant circuit
2 between the vapor cooler 8 and the second compressor 22 through the injection
valve passage 81. The opening degree of the injection valve 82 is controlled, for
35 example, based on the temperature of the refrigerant discharged from the second
compressor 22. That is, when the temperature of the refrigerant discharged from
the second compressor 22 is higher than a predetermined value, control for
20
increasing the opening degree of the injection valve 82 is performed.
[0083] In the case where the injection passage 81 is thus provided, the temperature
of the refrigerant to be drawn into the second compressor 22 can be significantly
lowered. Therefore, the reliability of the air conditioner 1C, in particular, the
reliability of the second compressor 22 can 5 be further improved.
[0084] As another modification, as shown in FIG. 10, the refrigerant circuit 2 may
be provided with a bypass passage 83 that bypasses the vapor cooler 8. The bypass
passage 83 is branched from the refrigerant circuit 2 at a position between the first
compressor 21 and the vapor cooler 8 and is connected to the refrigerant circuit 2 at
10 a position between the vapor cooler 8 and the second compressor 22. The bypass
passage 83 is provided with a flow rate regulating valve (a flow rate regulating
mechanism) 84.
[0085] In the case where the bypass passage 83 having the flow rate regulating
valve 84 is thus provided, the amount of heat released from the refrigerant vapor
15 between the first compressor 21 and the second compressor 22 can be optimally
controlled. In the case where a less amount of heat released from the refrigerant
vapor is enough for the operation of the air conditioner 1C under certain conditions,
the refrigerant liquid is allowed to flow preferentially in the bypass passage 83 so as
to perform control of reducing the amount of released heat. Thus, the COP and
20 comfort level of the air conditioner 1C are improved. The example of the method
for controlling the flow rate regulating valve 84 is as described in the first
embodiment.
[0086] In still another modification, as shown in FIG. 11, the air conditioner 1C
may include a third compressor 33 and a second vapor cooler 9. In the refrigerant
25 circuit 2, the evaporator 25, the first compressor 21, the vapor cooler 8 (a first vapor
cooler 8), the second compressor 22, the second vapor cooler 9, the third compressor
33, the condenser 23, and the expansion valve 24 are connected in this order.
[0087] The second vapor cooler 9 is a heat exchanger that exchanges heat between
the refrigerant vapor compressed by the second compressor 22 and air, and cools the
30 refrigerant vapor discharged from the second compressor 22 before the refrigerant
vapor is drawn into the third compressor 33. In this modification, the second vapor
cooler 9 is disposed indoors, like the first vapor cooler 8. As the second vapor cooler
9, for example, a fin-and-tube heat exchanger can be used.
[0088] More specifically, the second vapor cooler 9 is disposed in such a manner
35 that a wind generated by the indoor fan 51 passes through the first heat exchanger
5 and then through the first vapor cooler 8 and the second vapor cooler 9 in this
order. In other words, the first heat exchanger 5, the first vapor cooler 8, and the
21
second vapor cooler 9 are arranged side by side in the direction of the air flow by the
indoor fan 51, and the first vapor cooler 8 is located on the leeward side of the first
heat exchanger 5 and the second vapor cooler 9 is located on the leeward side of the
first vapor cooler 8. This configuration makes it possible to further enhance the
heating capacity of the air conditioner 1C. The locations of the 5 first vapor cooler 8
and the second vapor cooler 9 are not particularly limited.
[0089] (Fourth Embodiment)
FIG. 12 shows an air conditioner 1D according to the fourth embodiment of
the present invention.
10 [0090] In the present embodiment, the vapor cooler 8 is disposed so as to heat the
air to be supplied to the second heat exchanger 7. Specifically, the vapor cooler 8 is
disposed in such a manner that a wind generated by an outdoor fan 71 passes
through this vapor cooler 8 and then through the second heat exchanger 7. In
other words, the vapor cooler 8 and the second heat exchanger 7 are arranged side
15 by side in the direction of the air flow by the outdoor fan 71, and the vapor cooler 8
is located on the windward side of the second heat exchanger 7.
[0091] Next, how the air conditioner 1D works is described.
[0092] The refrigerant vapor compressed by the first compressor 21 releases heat to
the outdoor air in the vapor cooler 8, and then is drawn into the second compressor
20 22. The refrigerant vapor further compressed by the second compressor 22 is
condensed in the condenser 23 by heat exchange with the refrigerant liquid
supercooled in the first heat exchanger 5. A portion of the refrigerant liquid
resulting from the condensation in the condenser 23 is pumped to the first heat
exchanger 5 by the pump 43. The refrigerant liquid pumped to the first heat
25 exchanger 5 releases heat to the indoor air in the first heat exchanger 5, and then
returns to the condenser 23.
[0093] The remaining portion of the refrigerant liquid resulting from the
condensation in the condenser 23 is introduced into the evaporator 25 via the
expansion valve 24. A portion of the refrigerant liquid in the evaporator 25 is
30 pumped by the pump 63 to the second heat exchanger 7, absorbs heat from the
outdoor air heated by the vapor cooler 8 in the second heat exchanger 7, and then
returns to the evaporator 25. The refrigerant liquid in the evaporator 25 is
evaporated by being boiled under a reduced pressure, and the refrigerant vapor
resulting from the evaporation is drawn into the first compressor 21.
35 [0094] In the air conditioner 1D of the present embodiment, the heat released from
the refrigerant vapor in the vapor cooler 8 can be recovered by the refrigerant liquid
serving as a heat medium for cooling the outdoor air. Therefore, the heat loss in
22
the heating operation is significantly reduced. Thereby, the COP of the air
conditioner 1D can be improved.
[0095] In addition, since the air to be supplied to the second heat exchanger 7 is
heated, it is possible to raise the temperature of the refrigerant liquid flowing from
the second heat exchanger 7 and to increase the pressure of the 5 refrigerant vapor in
the evaporator 25. Thereby, the compression work of the first compressor 21 and
the second compressor 22 also can be reduced.
[0096] Furthermore, in the present embodiment, the amount of frost formed on the
second heat exchanger 7 in winter can be reduced. Therefore, the COP of the air
10 conditioner 1D in winter can be improved particularly effectively, and the comfort
level in the heating operation can be improved.
[0097]
Various modifications can be made to the air conditioner 1D of the
previously-described embodiment.
15 [0098] For example, as shown in FIG. 13, the air conditioner 1D may include an
injection passage 91 that injects the refrigerant liquid pumped from the pump 63 in
the heat absorption side feed path 61 into a section of the refrigerant circuit 2
between the vapor cooler 8 and the second compressor 22. In this case, the
injection is performed by means of pumping of the pump 63, as in the modification
20 of the third embodiment. The injection passage 91 is provided with an injection
valve 92 for regulating the injection flow rate.
[0099] In the case where the injection passage 91 is thus provided, the temperature
of the refrigerant to be drawn into the second compressor 22 can be lowered, as in
the modification of the third embodiment. Therefore, the reliability of the air
25 conditioner 1D, in particular, the reliability of the second compressor 22 can be
further improved.
[0100] As another modification, as shown in FIG. 14, the refrigerant circuit 2 may
be provided with a bypass passage 93 that bypasses the vapor cooler 8. The bypass
passage 93 is branched from the refrigerant circuit 2 at a position between the first
30 compressor 21 and the vapor cooler 8 and is connected to the refrigerant circuit 2 at
a position between the vapor cooler 8 and the second compressor 22. The bypass
passage 93 is provided with a flow rate regulating valve (a flow rate regulating
mechanism) 94.
[0101] In the case where the bypass passage 93 having the flow rate regulating
35 valve 94 is thus provided, the amount of heat released from the refrigerant vapor
between the first compressor 21 and the second compressor 22 can be optimally
controlled, as in the modification of the third embodiment. In the case where a less
23
amount of heat released from the refrigerant vapor is enough for the operation of
the air conditioner 1D under certain conditions, the refrigerant liquid is allowed to
flow preferentially in the bypass passage 93 so as to perform control of reducing the
amount of released heat. Thus, the COP and comfort level of the air conditioner
1D are improved. The example of the method for controlling 5 the flow rate
regulating valve 94 is as described in the second embodiment.
[0102] In still another modification, as shown in FIG. 15, the air conditioner 1D
may include a third compressor 33 and a second vapor cooler 9. In the refrigerant
circuit 2, the evaporator 25, the first compressor 21, the vapor cooler 8 (a first vapor
10 cooler 8), the second compressor 22, the second vapor cooler 9, the third compressor
33, the condenser 23, and the expansion valve 24 are connected in this order.
[0103] The second vapor cooler 9 is a heat exchanger that exchanges heat between
the refrigerant vapor compressed by the second compressor 22 and air, and cools the
refrigerant vapor discharged from the second compressor 22 before the refrigerant
15 vapor is drawn into the third compressor 33. In this modification, the second vapor
cooler 9 is disposed outdoors, like the first vapor cooler 8. As the second vapor
cooler 9, for example, a fin-and-tube heat exchanger can be used.
[0104] More specifically, the first vapor cooler 8 and the second vapor cooler 9 are
disposed on the windward side of the second heat exchanger 7. The first vapor
20 cooler 8 and the second vapor cooler 9 are disposed in such a manner that a wind
generated by the outdoor fan 71 passes through the first vapor cooler 8, the second
vapor cooler 9, and the second heat exchanger 7 in this order. In other words, the
second heat exchanger 7, the first vapor cooler 8, and the second vapor cooler 9 are
arranged side by side in the direction of the air flow by the outdoor fan 71, and the
25 second vapor cooler 9 is located on the leeward side of the first vapor cooler 8 and
the second heat exchanger 7 is located on the leeward side of the second vapor cooler
9. This configuration makes it possible to cool the refrigerant vapor efficiently.
The locations of the first vapor cooler 8 and the second vapor cooler 9 are not
particularly limited.
30 [0105] As shown in FIG. 16, in still another modification, the air conditioner 1D
includes a first circulation path 4a, a second circulation path 6a, a first switching
valve 27, a second switching valve 28, a third switching valve 14, and a fourth
switching valve 15. The structures, functions, locations, etc. of the first circulation
path 4a, the second circulation path 6a, the first switching valve 27, and the second
35 switching valve 28 are as described above with reference to FIG. 4.
[0106] The air conditioner 1D further includes two vapor coolers 8 (8a, 8b). The
vapor coolers 8a and 8b are both heat exchangers that exchange heat between the
24
refrigerant vapor compressed by the first compressor 21 and air, and cool the
refrigerant vapor discharged from the first compressor 21 before the refrigerant
vapor is drawn into the second compressor 22. The vapor cooler 8a (an indoor side
vapor cooler 8a) is disposed indoors, and the vapor cooler 8b (an outdoor side vapor
cooler 8b) is 5 disposed outdoors.
[0107] The third switching valve 14 and the fourth switching valve 15 are
controlled so that the refrigerant vapor is allowed to pass through only one selected
from the vapor coolers 8a and 8b. A specific example of each of the third switching
valve 14 and the fourth switching valve 15 is a three-way valve. In the heating
10 operation, the third switching valve 14 and the fourth switching valve 15 are
controlled so that the refrigerant vapor is allowed to pass through the vapor cooler
8a. In the cooling operation, the third switching valve 14 and the fourth switching
valve 15 are controlled so that the refrigerant vapor is allowed to pass through the
vapor cooler 8b. This configuration makes it possible to cool the refrigerant vapor
15 compressed by the first compressor 21 reliably when the operation is switched
between heating and cooling.
[0108] The structure, function, location, etc. of the vapor cooler 8a are as described
above with reference to FIG. 8. The structure, function, location, etc. of the vapor
cooler 8b are as described above with reference to FIG. 12. When the refrigerant
20 vapor flows through the vapor cooler 8b, the refrigerant liquid is fed from the
condenser 23 to the second heat exchanger 7. Therefore, the vapor cooler 8b can be
disposed so as to further heat the air heated in the second heat exchanger 7.
Specifically, the vapor cooler 8b is disposed in such a manner that a wind generated
by the outdoor fan 71 passes through the second heat exchanger 7 and then through
25 the vapor cooler 8b. In other words, the vapor cooler 8b and the second heat
exchanger 7 are arranged side by side in the direction of the air flow by the outdoor
fan 71, and the vapor cooler 8b is located on the leeward side of the second heat
exchanger 7.
[0109] (Other Embodiments)
30 In each of previously-described embodiments, the heat release circuit 4 and
the heat absorption circuit 6 are each a circuit that merges into the refrigerant
circuit 2 to bring the heat medium into direct contact with the refrigerant.
However, the heat release circuit 4 and the heat absorption circuit 6 may each be a
circuit that brings the heat medium into indirect contact with the refrigerant
35 without merging into the refrigerant circuit 2. That is, the heat release circuit 4
may have a flow path for heat exchange provided in the condenser 23, and the heat
absorption circuit 6 may have a flow path for heat exchange provided in the
25
condenser 25.
[0110] In addition, the air conditioner of the present invention may be configured
in any manner as long as it can perform at least heating operation, and the second
heat exchanger 7 may be, for example, a heat exchanger that absorbs heat from a
5 liquid.
INDUSTRIAL APPLICABILITY
[0111] The refrigeration apparatus of the present invention is useful for air
conditioners, chillers, heat storage devices, etc., and is particularly useful for
10 household air conditioners, industrial air conditioners, etc.
26
CLAIMS
1. A refrigeration apparatus comprising:
a refrigerant circuit that allows a refrigerant to circulate, the refrigerant
5 circuit comprising
an evaporator that retains a refrigerant liquid and that evaporates
the refrigerant liquid therein,
a first compressor that compresses a refrigerant vapor,
a vapor cooler that cools the refrigerant vapor,
10 a second compressor that compresses the refrigerant vapor, and
a condenser that condenses the refrigerant vapor therein and that
retains the refrigerant liquid, wherein the evaporator, the first compressor, the
vapor cooler, the second compressor, and the condenser are connected in this order;
a heat release circuit that allows a heat medium to circulate between the
15 condenser and a first heat exchanger that releases heat to the atmosphere; and
a heat absorption circuit that allows a heat medium to circulate between the
evaporator and a second heat exchanger,
wherein
the heat release circuit comprises a heat release side feed path that feeds
20 the heat medium from the condenser to the first heat exchanger, and a heat release
side return path that returns the heat medium from the first heat exchanger to the
condenser, and
the vapor cooler is a heat exchanger that exchanges heat between the
refrigerant vapor compressed by the first compressor and the heat medium flowing
25 in the heat release side feed path of the heat release circuit.
2. The refrigeration apparatus according to claim 1, wherein
the heat medium circulating in the heat release circuit is the refrigerant
liquid retained in the condenser,
30 the heat release side feed path is provided with a pump, and
the vapor cooler is disposed on the heat release side feed path.
3. The refrigeration apparatus according to claim 1, wherein
the heat medium circulating in the heat absorption circuit is the refrigerant
35 liquid retained in the evaporator,
the heat absorption circuit comprises a heat absorption side feed path that
feeds the refrigerant liquid from the evaporator to the second heat exchanger and
27
that is provided with a pump, and a heat absorption side return path that returns
the refrigerant liquid from the second heat exchanger to the evaporator, and
the refrigeration apparatus further comprises an injection passage that
injects the refrigerant liquid pumped from the pump in the heat absorption side
feed path into a section of the refrigerant circuit between the 5 vapor cooler and the
second compressor.
4. The refrigeration apparatus according to claim 2, wherein the heat release
side feed path is provided with a bypass passage that bypasses the vapor cooler, and
10 the bypass passage is provided with a flow rate regulating mechanism.
5. A refrigeration apparatus comprising:
a refrigerant circuit that allows a refrigerant to circulate, the refrigerant
circuit comprising
15 an evaporator that retains a refrigerant liquid and that evaporates
the refrigerant liquid therein,
a first compressor that compresses a refrigerant vapor,
a vapor cooler that cools the refrigerant vapor,
a second compressor that compresses the refrigerant vapor, and
20 a condenser that condenses the refrigerant vapor therein and that
retains the refrigerant liquid, wherein the evaporator, the first compressor, the
vapor cooler, the second compressor, and the condenser are connected in this order;
a heat release circuit that allows a heat medium to circulate between the
condenser and a first heat exchanger that releases heat to the atmosphere; and
25 a heat absorption circuit that allows a heat medium to circulate between the
evaporator and a second heat exchanger,
wherein
the heat absorption circuit comprises a heat absorption side feed path that
feeds the heat medium from the evaporator to the second heat exchanger, and a
30 heat absorption side return path that returns the heat medium from the second
heat exchanger to the evaporator, and
the vapor cooler is a heat exchanger that exchanges heat between the
refrigerant vapor compressed by the first compressor and the heat medium flowing
in the heat absorption side feed path of the heat absorption circuit.
35
6. The refrigeration apparatus according to claim 5, wherein
the heat medium circulating in the heat absorption circuit is the refrigerant
28
liquid retained in the evaporator,
the heat absorption side feed path is provided with a pump,
the vapor cooler is disposed on the heat absorption side feed path, and
the refrigeration apparatus further comprises an injection passage that
injects the refrigerant liquid pumped from the pump in the heat 5 absorption side
feed path into a section of the refrigerant circuit between the vapor cooler and the
second compressor.
7. The refrigeration apparatus according to claim 5, wherein
10 the heat medium circulating in the heat absorption circuit is the refrigerant
liquid retained in the evaporator,
the vapor cooler is disposed on the heat absorption side feed path, and
the heat absorption side feed path is provided with a bypass passage that
bypasses the vapor cooler, and the bypass passage is provided with a flow rate
15 regulating mechanism.
8. The refrigeration apparatus according to claim 5, wherein
the heat medium circulating in the heat release circuit is the refrigerant
liquid retained in the condenser, and
20 the heat release circuit comprises a heat release side feed path that feeds
the refrigerant liquid from the condenser to the first heat exchanger and that is
provided with a pump, and a heat release side return path that returns the
refrigerant liquid from the first heat exchanger to the condenser.
25 9. The refrigeration apparatus according to claim 1, wherein the second heat
exchanger is a heat exchanger that absorbs heat from the atmosphere.
10. A refrigeration apparatus comprising:
a refrigerant circuit that allows a refrigerant to circulate, the refrigerant
30 circuit comprising
an evaporator that retains a refrigerant liquid and that evaporates
the refrigerant liquid therein,
a first compressor that compresses a refrigerant vapor,
a vapor cooler that cools the refrigerant vapor,
35 a second compressor that compresses the refrigerant vapor, and
a condenser that condenses the refrigerant vapor therein and that
retains the refrigerant liquid, wherein the evaporator, the first compressor, the
29
vapor cooler, the second compressor, and the condenser are connected in this order;
a heat release circuit that allows a heat medium to circulate between the
condenser and a first heat exchanger that releases heat to indoor air; and
a heat absorption circuit that allows a heat medium to circulate between the
evaporator and a second heat exchanger that absorbs heat 5 from outdoor air,
wherein
the vapor cooler is a heat exchanger that exchanges heat between the
refrigerant vapor compressed by the first compressor and air, and is disposed
indoors or is disposed so as to heat the air to be supplied to the second heat
10 exchanger.
11. The refrigeration apparatus according to claim 10, further comprising an
indoor fan that supplies the indoor air to the first heat exchanger, wherein
the vapor cooler is disposed in such a manner that a wind generated by the
15 indoor fan passes through the first heat exchanger and then through the vapor
cooler.
12. The refrigeration apparatus according to claim 10, wherein
the heat medium circulating in the heat absorption circuit is the refrigerant
20 liquid retained in the evaporator,
the heat absorption circuit comprises a heat absorption side feed path that
feeds the refrigerant liquid from the evaporator to the second heat exchanger and
that is provided with a pump, and a heat absorption side return path that returns
the refrigerant liquid from the second heat exchanger to the evaporator, and
25 the refrigeration apparatus further comprises an injection passage that
injects the refrigerant liquid pumped from the pump in the heat absorption side
feed path into a section of the refrigerant circuit between the vapor cooler and the
second compressor.
30 13. The refrigeration apparatus according to claim 10, wherein the refrigerant
circuit is provided with a bypass passage that bypasses the vapor cooler, and the
bypass passage is provided with a flow rate regulating mechanism.
14. The refrigeration apparatus according to claim 10, wherein
35 the heat medium circulating in the heat release circuit is the refrigerant
liquid retained in the condenser, and
the heat release circuit comprises a heat release side feed path that feeds
30
the refrigerant liquid from the condenser to the first heat exchanger and that is
provided with a pump, and a heat release side return path that returns the
refrigerant liquid from the first heat exchanger to the condenser.