JP2010255965A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner of high energy efficiency by reducing in-pipe refrigerant pressure loss of an indoor heat exchanger and a pressure loss in piping connecting an indoor cycle and an outdoor cycle, and improving indoor heat exchanging performance in a cooling operation and a dehumidifying operation, in an air conditioner using a HFO-1234yf refrigerant and having a dehumidifying valve on the way of the piping of the indoor heat exchanger. <P>SOLUTION: In this air conditioner performing cooling, heating and dehumidifying operations by circulating a HFO-1234yf single refrigerant, or a mixed refrigerant prepared by mixing HFO-1234yf and another refrigerant as a working fluid, a gas-liquid separator is disposed at a downstream side of the dehumidifying valve and an upstream side of a second indoor heat exchanger, and a gas refrigerant after gas-liquid separation by the gas-liquid separator is allowed to flow to a suction side of a compressor through a flow rate adjustment valve in a cooling operation. Thus pressure loss of the refrigerant flowing into the indoor heat exchanger and the connection piping is reduced, and cooling performance and dehumidifying performance are improved. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat pump using HFO-1234yf alone having a low global warming potential (GWP) or a mixed refrigerant in which HFO-1234yf and an existing refrigerant are combined.

  As an air conditioner that is often used in general households, an indoor unit and an outdoor unit are configured separately, and a heat exchanger for exchanging heat between the air and the refrigerant and a blower that sends out air are contained in the indoor unit. In the outdoor unit, a heat exchanger and a blower for exchanging heat between the air and the refrigerant, a compressor for circulating the refrigerant, a decompressor for depressurizing the refrigerant, and the like are installed. By connecting the refrigerant flow path between the indoor unit and the outdoor unit using a connection pipe, the refrigerant goes back and forth between the indoor unit and the outdoor unit to establish a refrigeration cycle.

  In the air conditioner having this configuration, cooling operation, heating operation, and dehumidification operation are performed by changing the flow direction of the refrigerant using a refrigerant flow path switching valve or the like. There has been a great deal of research.

  On the other hand, in recent years, as a part of global environmental protection, the air conditioning industry as a whole has been studying switching to refrigerants with low global warming potential (GWP) in air conditioners. Among them, HFO-1234yf has recently been developed as a next-generation refrigerant with a low global warming potential. This refrigerant is close in thermophysical properties to HFC-134a that has been used in conventional car air conditioners, and is being studied and put into practical use by the European Automobile Manufacturers Association.

  In response to this flow, air conditioners other than car air conditioners, that is, room air conditioners and commercial air conditioners, can be used as alternative refrigerants such as R410A and R407C having a high global warming potential. The manufacturer is making an assessment.

  However, this refrigerant has a lower operating pressure than refrigerants such as R410A that have been used in room air conditioners and commercial air conditioners, and in particular, the refrigerant in the heat exchanger and in the connecting pipe that connects the indoor cycle and the outdoor cycle. Pressure loss has a large effect on performance, and according to the result of a test (drop-in test) in which only a refrigerant is replaced with a conventional device, the cooling performance is reduced by half compared to the conventional one. The refrigerant pressure loss of the indoor heat exchanger at this time is about 2 to 3 times that of the R410A ratio, and since the overall pressure is low, the loss ratio increases.

  Thus, when the refrigerant | coolant of HFO-1234yf is used as a working fluid, in a room air-conditioner etc., it is necessary to perform the substantial apparatus structure improvement with respect to this low voltage | pressure refrigerant | coolant. Considering the characteristics of the refrigerant in particular, significant improvement measures are required to reduce the pressure loss in the heat exchanger or in the connecting pipe.

  While developing room air conditioners and other products so far, as an effective means to reduce the pressure loss of refrigerant during operation, reducing the pressure loss by reducing the flow rate of refrigerant by using multiple heat exchangers I have been trying. However, when the refrigerant flow is multipassed in the heat exchanger, most of the refrigerant flow is divided into each flow path in the state of a two-phase flow refrigerant in which a gas refrigerant and a liquid refrigerant are mixed. At this time, the problem is that the liquid refrigerant drifts and the heat exchange amount after being divided into each flow path is lost, resulting in performance degradation. In the past product development, various manufacturers have conducted various studies, but the reality is that they have not been completely solved.

  When a heat exchanger is used as an evaporator, as a method for reducing refrigerant pressure loss, for example, as disclosed in Patent Document 1, a gas-liquid separator is provided before flowing into a heat exchanger serving as an evaporator, and pressure loss is reduced. There is an example of improving the performance by reducing the pressure loss by bypassing the gas refrigerant which is one of the increasing factors.

JP 2003-5060 A

  However, in Patent Document 1, gas-liquid separation is performed in the outdoor unit before flowing into the indoor heat exchanger, so that pressure loss from the indoor heat exchanger inlet to the outlet is reduced and multiple passes are made at the heat exchanger inlet. It is effective as a method for improving the cooling performance and the heating performance in that it can reduce pressure loss without performing dehumidification, but a dehumidification valve is provided in the middle of the piping path from the refrigerant inlet to the refrigerant outlet of the indoor heat exchanger. When the dehumidifying valve is closed, the heat exchanger on the refrigerant upstream side of the dehumidifying valve is used as a condenser, and the refrigerant downstream side of the dehumidifying valve is used as an evaporator. In this known example, no consideration is given during dehumidifying operation. Therefore, improvement in dehumidifying efficiency during dehumidifying operation cannot be expected.

  Further, regarding the cooling operation, the dryness of the refrigerant at the time of gas-liquid separation is separated in a state where there is a large amount of liquid refrigerant, so that the effect of removing the gas refrigerant is reduced.

  In this known example, since the dehumidifying valve is used in the middle of the piping path from the refrigerant inlet to the refrigerant outlet of the indoor heat exchanger as described above, in this configuration, the refrigerant is used in the heat exchanger downstream of the dehumidifying valve. Can be assumed to be unstable because of the diversion in a state where there is a large amount of gas refrigerant.

  Furthermore, as a result of a drop-in test on HFO-1234yf, when the cooling performance was compared under the assumption that the compressor and inverter efficiencies were equivalent, a result was obtained that the COP ratio at the same capacity as R410A was reduced by about 50%. . Comparing the refrigerant pressure loss in this state, it was found that the pressure loss from the indoor heat exchanger outlet to the compressor inlet was about 9 times as large as about 2.5 times in the indoor heat exchanger relative to R410A. . From this, it has been found that HFO-1234yf requires a significant improvement in cooling performance, and in particular, reduction of pressure loss in the connecting piping connecting the indoor cycle and the outdoor cycle is a major issue. Moreover, it can be easily estimated from this result that it is necessary to take a similar measure for reducing pressure loss even during the dehumidifying operation.

  Therefore, the present invention takes the above circumstances into consideration, and in claim 1, a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, a first indoor heat exchanger that serves as a condenser during dehumidification operation, and A second indoor heat exchanger that serves as an evaporator, and a dehumidification valve that is located downstream of the first heat exchanger and upstream of the second indoor heat exchanger during dehumidifying operation and depressurizes the refrigerant. Machine, four-way valve, outdoor heat exchanger, expansion valve, first indoor heat exchanger, second indoor heat exchanger, and dehumidification valve are connected by a refrigerant pipe to form a refrigerant circuit, and HFO-1234yf alone as a working fluid An air conditioner that circulates a refrigerant or a mixed refrigerant obtained by mixing HFO-1234yf and another refrigerant to perform cooling, heating, and dehumidifying operation, and is located on the downstream side of the dehumidifying valve and in the second indoor heat exchange during the cooling operation A gas-liquid separator is placed upstream of the vessel, and the gas-liquid separator is used Characterized in that to flow into the suction side of the compressor gas refrigerant through the flow control valve.

  Further, in claim 2, in addition to the features of claim 1, a branch pipe or a distributor for dividing the refrigerant into a plurality of flow paths is arranged downstream of the dehumidification valve and upstream of the second indoor heat exchanger during cooling operation. And the refrigerant | coolant divided into the several flow path is made to merge by the exit side of a 2nd indoor heat exchanger.

  Furthermore, in claim 3, in addition to the features of claim 1 or 2, the mixed refrigerant is a mixture ratio of HFO-1234yf and another refrigerant such that the global warming potential (GWP) does not exceed 150. And

  According to the first aspect of the present invention, the HFO-1234yf single refrigerant or a mixed refrigerant obtained by mixing HFO-1234yf and another refrigerant is circulated as a working fluid to perform air conditioning that performs cooling, heating, and dehumidifying operations. A gas-liquid separator is disposed downstream of the dehumidifying valve and upstream of the second indoor heat exchanger during cooling operation, and the gas refrigerant separated by the gas-liquid separator is supplied with a flow regulating valve. The two-phase flow refrigerant having a large ratio of gas refrigerant flowing out from the first indoor heat exchanger through the dehumidification valve during the cooling operation is gas refrigerant in the gas-liquid separator. The gas refrigerant separated by the gas-liquid separator is directly joined to the compressor suction pipe of the outdoor cycle via the flow rate adjusting valve, and the liquid refrigerant is caused to flow into the second indoor heat exchanger.

  The first effect of this is that, after passing through the dehumidification valve, the flow was divided in the liquid / gas mixed state. However, the heat exchange due to the deviation of the liquid refrigerant due to the variation in the flow divider installation and the variation in mass production. As a result, there was a variation in the amount of refrigerant, a difference in refrigerant temperature at the outlet of the heat exchanger, and finally, there was a variation in the performance of the heat exchanger depending on the mass-produced product. Therefore, by removing the gas refrigerant at the time of diversion by using a gas-liquid separator, the refrigerant at the time of diversion can be made almost liquid liquor, so the diversion ratio with respect to the case of diversion by liquid / gas mixture Can be stabilized, and it becomes easy to control the diversion balance when the heat exchanger is divided into multiple paths. As a second effect, the pressure loss of the second indoor heat exchanger can be reduced by causing the liquid refrigerant from which the gas refrigerant has been removed by the gas-liquid separator to flow into the second indoor heat exchanger. The third effect is that the liquid refrigerant separated by the gas / liquid separator and the connecting pipe for sending the gas refrigerant extracted by the gas / liquid separator to the compressor suction section passes through the second indoor heat exchanger. By using two return connection pipes for the piping to be sent to the outdoor cycle, the pressure loss of the connection pipe can be reduced, thereby reducing the pressure loss in the heat exchanger and the connection pipe and improving the cooling performance. As a fourth effect, when dehumidifying operation is performed by closing the dehumidifying valve in the refrigerant flow direction during cooling operation, a gas that does not contribute to heat exchange by providing a gas-liquid separator on the refrigerant downstream side of the dehumidifying valve By bypassing the refrigerant to the compressor suction pipe in the same manner as in the cooling operation, the refrigerant diversion performance can be improved, the pressure loss can be reduced, and the dehumidification performance can be improved.

  According to the second aspect of the present invention, a branch pipe or a distributor for diverting the refrigerant into a plurality of flow paths is disposed downstream of the dehumidification valve and upstream of the second indoor heat exchanger during the cooling operation, Since the refrigerant split into the plurality of flow paths is merged at the outlet side of the heat exchanger, the refrigerant flowing out from the gas-liquid separator is a liquid refrigerant as described above, so that even if there are multiple passes, the diversion ratio is stabilized. Can do. At this time, even when the pipes constituting the second indoor heat exchanger are made smaller in diameter than the first indoor heat exchanger, a low pressure loss can be achieved by making more path configurations while stabilizing the diversion ratio. The performance can be improved while maintaining the above. Further, since it is not necessary to use a special branch pipe when diverting, the cost can be reduced.

  Further, the effect of claim 3 is that the mixed refrigerant has a mixing ratio of HFO-1234yf and other refrigerants such that the global warming potential (GWP) does not exceed 150, and therefore HFC-32 which is a high pressure refrigerant. Is mixed with HFO-1234yf which is a low-pressure refrigerant, the operating pressure of the refrigeration cycle in the operating state can be increased as a whole, and the rate of performance degradation due to pressure loss can be mitigated. However, in this case, as described above, the effect of protecting the global environment can be obtained by adjusting the mixing ratio so that the global warming potential (GWP) does not exceed the guideline of 150.

It is explanatory drawing which showed the implementation method of the air conditioner which concerns on this invention. It is explanatory drawing which showed the structure of the domestic air conditioner. It is explanatory drawing which showed the structure of the conventional air conditioner. It is a Mollier diagram of the conventional cycle. It is explanatory drawing which showed the implementation method of the other air conditioner which concerns on this invention. It is explanatory drawing which showed the implementation method of the air conditioner which concerns on this invention.

  The best mode for carrying out the present invention is a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, and a second indoor heat exchanger and an evaporator that serve as a condenser during dehumidifying operation. An indoor heat exchanger and a dehumidifying valve that is located downstream of the first heat exchanger and upstream of the second indoor heat exchanger during dehumidifying operation and depressurizes the refrigerant, and includes a compressor, a four-way valve, and an outdoor unit A refrigerant circuit is formed by connecting a heat exchanger, an expansion valve, a first indoor heat exchanger, a second indoor heat exchanger, and a dehumidification valve with a refrigerant pipe, and HFO-1234yf single refrigerant or HFO-1234yf is used as a working fluid. An air conditioner that circulates a mixed refrigerant mixed with other refrigerants to perform cooling, heating, and dehumidifying operation, and that is disposed downstream of the dehumidifying valve and upstream of the second indoor heat exchanger during cooling operation. A liquid separator is installed to adjust the flow rate of the gas refrigerant separated by the gas-liquid separator. To flow into the suction side of the compressor via a valve. As a result, the two-phase flow refrigerant having a large gas refrigerant ratio flowing out from the first indoor heat exchanger through the dehumidifying valve during the cooling operation is divided into the gas refrigerant and the liquid refrigerant by the gas-liquid separator. The gas refrigerant separated by the separator is directly joined to the compressor suction pipe of the outdoor cycle via a flow rate adjusting valve, and the liquid refrigerant is caused to flow into the second indoor heat exchanger. As a first effect, after passing through the dehumidifying valve, the flow is divided in the liquid / gas mixed state. However, due to variations in the distribution of the flow divider and variations in the shape during mass production, the amount of heat exchange due to the liquid refrigerant bias is reduced. There was a variation, and a difference in the refrigerant temperature at the outlet of the heat exchanger occurred, resulting in a variation in the performance of the heat exchanger due to mass production. Therefore, by removing the gas refrigerant at the time of diversion by using a gas-liquid separator, the refrigerant at the time of diversion can be made almost liquid liquor, so the diversion ratio with respect to the case of diversion by liquid / gas mixture Can be stabilized, and it becomes easy to control the diversion balance when the heat exchanger is divided into multiple paths. As a second effect, the pressure loss of the second indoor heat exchanger can be reduced by causing the liquid refrigerant from which the gas refrigerant has been removed by the gas-liquid separator to flow into the second indoor heat exchanger. The third effect is that the liquid refrigerant separated by the gas / liquid separator and the connecting pipe for sending the gas refrigerant extracted by the gas / liquid separator to the compressor suction section passes through the second indoor heat exchanger. By using two return connection pipes for piping to the outdoor cycle, the pressure loss of the connection pipe can be reduced, thereby enabling effective use of the heat exchanger and at the same time improving the cooling performance by reducing the pressure loss. As a fourth effect, when dehumidifying operation is performed by closing the dehumidifying valve in the refrigerant flow direction during cooling operation, a gas that does not contribute to heat exchange by providing a gas-liquid separator on the refrigerant downstream side of the dehumidifying valve By bypassing the refrigerant to the compressor suction pipe in the same manner as in the cooling operation, the refrigerant diversion performance can be improved, the pressure loss can be reduced, and the dehumidification performance can be improved. That is, the purpose of improving the cooling performance and the dehumidifying performance was realized.

  FIG. 2 is a diagram showing a configuration of a general household air conditioner. An indoor heat exchanger 7 and an indoor fan 8 are incorporated in the indoor unit 20, and the indoor heat exchanger 7 is disposed so as to surround the indoor fan 8 in order to effectively use a small space. The wind flows in the air flow direction shown in the figure by rotating the. At this time, the air that has flowed in is heat-exchanged by the indoor heat exchanger 7 so that the air that has flowed in is cooled during the cooling operation, and the air that has flowed in is heated and blown out during the heating operation. In addition, in the outdoor unit 21, a compressor 1 for making the refrigerant as a working fluid high temperature and high pressure, a four-way valve 2 for switching the cooling and heating refrigerant flow directions, outdoor heat exchange (not shown). And an outdoor fan 4 for sending air to the outdoor heat exchanger, an expansion valve 5 for depressurizing the refrigerant, etc., and rotating the outdoor fan 4 in the same manner as the indoor unit 20 flows in the outdoor heat exchanger. Heat is exchanged between the refrigerant and air, the refrigerant is cooled during cooling operation, and the refrigerant is warmed during heating operation. The indoor cycle and the outdoor cycle are connected by a small diameter connecting pipe 6 and a large diameter connecting pipe 9, and a refrigerant is sealed inside as a working fluid. FIG. 3 shows these in a simple cycle configuration diagram.

  When FIG. 3 is described in the flow direction of the refrigerant during the cooling operation, the refrigerant converted into the high-temperature and high-pressure gas by the compressor 1 flows into the outdoor heat exchanger 3 through the four-way valve 2, and the outdoor heat exchanger 3. In this case, heat is exchanged with the air sent by the outdoor fan 4 to be condensed into liquid refrigerant, and the expansion valve 5 becomes low-temperature and low-pressure two-phase flow refrigerant. The two-phase flow refrigerant that has become low temperature and low pressure flows into the indoor heat exchanger 7 in the indoor unit 20 through the small diameter connecting pipe 6 and exchanges heat with the air sent by the indoor fan 8. It returns to the compressor 1 again through the connecting pipe 9 and the four-way valve 2. FIG. 4 shows this in a theoretical Mollier diagram.

  Referring to FIG. 4, the vertical axis in FIG. 4 represents pressure, and the horizontal axis represents specific enthalpy, and (1) to (2) in the figure are processes in which the compressor 1 compresses the refrigerant. At this time, normally, when the state of the refrigerant before compression is (1), the refrigerant is compressed along the isentropic line (2). (2) to (3) show the state in which the refrigerant in the heat exchanger and the air sent by the fan exchange heat, and the high-temperature / high-pressure refrigerant in (2) becomes a two-phase refrigerant while dissipating heat. It becomes a supercooled state and reaches (3). (3) to (4) are states in which the refrigerant is decompressed by the expansion valve. At this time, the refrigerant of (3) is in the state of (4) in an isenthalpy state. From (4) to (1), the air sent by the refrigerant and the fan in the heat exchanger exchanges heat, the refrigerant is warmed, and the air is cooled. A refrigeration cycle is configured by repeating such a cycle. At this time, since the actual refrigeration cycle is accompanied by a pressure loss when heat is exchanged from (4), the pressure drops from the theory as in (1) ′. Further, the refrigerant compressed from the state (1) deviates from the theoretical value as shown in (2) ′ by the efficiency of the actual compressor. Therefore, the refrigeration cycle in actual operation is as shown by the broken line in FIG.

  In such a basic refrigeration cycle, the refrigeration cycle according to the present invention is configured as shown in FIG. 1 will be described in order in the refrigerant flow direction during the cooling operation, the refrigerant having high temperature and high pressure in the compressor 1 flows into the outdoor heat exchanger 3 inside the outdoor unit via the four-way valve 2. In the outdoor heat exchanger 3, the refrigerant exchanges heat with the air sent by the outdoor fan 4 and reaches the expansion valve 5. In the expansion valve 5, the refrigerant is depressurized by an isenthalpy change and reaches the small diameter connecting pipe 6. The refrigerant passes through the small diameter connecting pipe 6 and flows into the indoor heat exchanger 7, and exchanges heat with the air sent by the indoor fan 8, and then again through the large diameter connecting pipe 9 and the four-way valve 2. Return to.

  Here, the indoor heat exchanger 7 is divided into a first indoor heat exchanger 11 and a second indoor heat exchanger 12 by a dehumidifying valve 10 that can depressurize the refrigerant during the dehumidifying operation. By restricting the dehumidifying valve 10, the first indoor heat exchanger 11 on the upstream side with respect to the flow direction of the refrigerant sandwiching the dehumidifying valve 10 becomes a condenser, and the second indoor heat exchanger 12 on the downstream side becomes an evaporator. Become.

  At this time, in the indoor heat exchanger 7, the gas-liquid separator 13 is installed on the refrigerant downstream side of the dehumidifying valve 10, and the second indoor heat exchanger 12 located on the refrigerant downstream side of the gas-liquid separator 13 is used as the refrigerant. The second connecting pipe 17 is connected by piping and further bypassed from the gas-liquid separator 13 to the compressor suction pipe 16 via the flow rate adjusting valve 15.

  In the air conditioner having such a configuration, the refrigerant flows into the gas-liquid separator 13 located on the downstream side of the dehumidifying valve 10 by adjusting the opening of the flow rate adjusting valve 15 according to the rotational speed of the compressor during the cooling operation. Is separated into liquid refrigerant and gas refrigerant. Thereafter, the refrigerant that has become substantially liquid flows into the second indoor heat exchanger 12 and reaches the outlet pipe 14 while performing heat exchange. On the other hand, the gas refrigerant separated by the gas-liquid separator 13 is guided to the suction pipe 16 of the compressor 1 through the flow rate adjusting valve 15 without flowing into the second indoor heat exchanger 12 through the second connection pipe 17. .

  As described above, the refrigerant HFO-1234yf has a lower operating pressure than the conventionally used refrigerant such as R410A, and has a large influence on the performance of the refrigerant in terms of pressure loss. Also, the refrigerant itself has a characteristic that the pressure loss is large, and the cycle performance when this refrigerant is used is determined depending on how the pressure loss causes a cycle configuration.

  As described in the prior art, multi-pass is an effective means to reduce refrigerant pressure loss, but if multi-pass is easily made, the diversion ratio becomes unstable and the cycle pipe becomes complicated. Workability also decreases.

  There is also a known example in which a gas-liquid separator is provided in the middle of the piping path from the expansion valve to the indoor heat exchanger inlet to reduce the pressure loss of the refrigerant. Therefore, it can be estimated that the effect of separation at the entrance is small.

  Further, the point that the pressure loss of the connecting pipe from the indoor cycle to the outdoor cycle during the cooling operation is about nine times as large as R410A is not in a range that can be improved by the conventional pipe connecting method. For example, if the connecting pipe is made thick, the pipe is difficult to bend and the installation property is lowered. There is also a risk of breakage depending on the situation.

  When these are considered together, the gas-liquid separator 13 is arranged in the middle of the indoor heat exchanger, which has not been considered in the past, and downstream of the dehumidifying valve 10 during the cooling operation, and is separated by the gas-liquid separator 13. As the gas refrigerant is in the second connection pipe 17, the pressure loss of the connection pipe is reduced and the indoor heat exchange is performed by returning the refrigerant to the compressor 1 through a separate path from the return large-diameter connection pipe 9 from the conventional indoor heat exchanger 7. The pressure loss of the vessel 7 can be reduced.

  Further, by closing the dehumidifying valve 10, the first indoor heat exchanger 11 acts as a condenser and the second indoor heat exchanger 12 acts as an evaporator, so that the dehumidifying operation can be performed without lowering the temperature of air blown from the indoor unit. Even in the case where the gas refrigerant is used, the gas-liquid separator 13 can separate the refrigerant into a gas refrigerant and a liquid refrigerant. By bypassing the gas refrigerant to the compressor suction pipe 16, the same effect as in the cooling operation can be obtained.

  FIG. 5 shows an example in which the second large-diameter connection pipe 9 ′ is added. With such a configuration, pressure loss in the connection pipe can be further reduced, and performance can be improved.

  FIG. 6 shows an embodiment of the second aspect of the present invention.

  If it demonstrates in order by the flow direction of the refrigerant | coolant at the time of air_conditionaing | cooling operation, the refrigerant | coolant which became high temperature and the high pressure in the compressor 1 will flow into the outdoor heat exchanger 3 inside an outdoor unit via the four-way valve 2. FIG. In the outdoor heat exchanger 3, the refrigerant exchanges heat with the air sent by the outdoor fan 4 and reaches the expansion valve 5. In the expansion valve 5, the refrigerant is depressurized by an isenthalpy change and reaches the small diameter connecting pipe 6. The refrigerant passes through the small diameter connecting pipe 6 and flows into the indoor heat exchanger 7, and exchanges heat with the air sent by the indoor fan 8, and then again through the large diameter connecting pipe 9 and the four-way valve 2. Return to.

  Here, the indoor heat exchanger 7 is divided into a first indoor heat exchanger 11 and a second indoor heat exchanger 12 by a dehumidifying valve 10 that can depressurize the refrigerant during the dehumidifying operation. By restricting the dehumidifying valve 10, the first indoor heat exchanger 11 on the upstream side with respect to the flow direction of the refrigerant sandwiching the dehumidifying valve 10 becomes a condenser, and the second indoor heat exchanger 12 on the downstream side becomes an evaporator. Become.

  At this time, in the indoor heat exchanger 7, the gas-liquid separator 13 is installed on the refrigerant downstream side of the dehumidifying valve 10, and the second indoor heat exchanger 12 located on the refrigerant downstream side of the gas-liquid separator 13 is used as the refrigerant. The second connecting pipe 17 is connected by piping and further bypassed from the gas-liquid separator 13 to the compressor suction pipe 16 via the flow rate adjusting valve 15.

  In the air conditioner having such a configuration, the refrigerant flows into the gas-liquid separator 13 downstream of the dehumidification valve 10 by adjusting the opening of the flow rate adjustment valve 15 according to the rotation speed of the compressor during cooling operation. Separated into liquid refrigerant and gas refrigerant. Thereafter, the refrigerant that has become substantially liquid flows into the second indoor heat exchanger 12 and reaches the outlet pipe 14 while performing heat exchange. On the other hand, the gas refrigerant separated by the gas-liquid separator 13 is guided to the suction pipe 16 of the compressor 1 through the flow rate adjusting valve 15 without flowing into the second indoor heat exchanger 12 through the second connection pipe 17. .

  At this time, the second indoor heat exchanger 12 is divided into multiple paths by the branch pipe 18, but the gas component is removed downstream of the refrigerant of the dehumidifying valve 10, and the flow is divided in a substantially liquid state at the time of the diversion, so the diversion ratio is set. While being stabilized, the pressure loss of the second indoor heat exchanger 12 due to the multi-pass can be reduced, and the performance can be improved.

  Moreover, also in the dehumidification system which depressurizes with the dehumidification valve 10, the gas-liquid separator 13 located downstream of the dehumidification valve 10 can acquire the effect similar to the time of air_conditionaing | cooling operation, and can also improve dehumidification performance.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 4 Outdoor fan 5 Expansion valve 6 Small diameter connection piping 7 Indoor heat exchanger 8 Indoor fan 9 Large diameter connection piping 9 '2nd large diameter connection piping 10 Dehumidification valve 11 1st indoor Heat exchanger 12 Second indoor heat exchanger 13 Gas-liquid separator 14 Outlet pipe 15 Flow rate adjusting valve 16 Compressor suction pipe 17 Second connection pipe 18 Branch pipe 20 Indoor unit 21 Outdoor unit

Claims (3)

A compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, a first indoor heat exchanger serving as a condenser during dehumidifying operation, a second indoor heat exchanger serving as an evaporator, and the first during dehumidifying operation. A dehumidification valve that is located downstream of the heat exchanger and upstream of the second indoor heat exchanger and depressurizes the refrigerant,
Connecting the compressor, the four-way valve, the outdoor heat exchanger, the expansion valve, the first indoor heat exchanger, the second indoor heat exchanger, and a dehumidifying valve with a refrigerant pipe to form a refrigerant circuit; An air conditioner that performs cooling, heating, and dehumidifying operations by circulating a HFO-1234yf single refrigerant or a mixed refrigerant obtained by mixing HFO-1234yf and another refrigerant as a working fluid,
A gas-liquid separator is disposed downstream of the dehumidifying valve and upstream of the second indoor heat exchanger during cooling operation, and the gas refrigerant separated by the gas-liquid separator is passed through the flow rate adjustment valve. An air conditioner that flows into a suction side of the compressor.   2. The second indoor heat exchange according to claim 1, wherein a branch pipe or a distributor for diverting a refrigerant into a plurality of flow paths is disposed downstream of the dehumidifying valve and upstream of the second indoor heat exchanger during cooling operation. An air conditioner characterized in that the refrigerant divided into a plurality of flow paths is merged on the outlet side of the vessel.   3. The air conditioner according to claim 1, wherein the mixed refrigerant is a mixture ratio of the HFO-1234yf and the other refrigerant such that a global warming potential (GWP) does not exceed 150. 4.

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