KR101452690B1 - Refrigeration device - Google Patents

Abstract

The air conditioning apparatus 1 is configured such that the refrigerant flows in the order of the compressor 21, the outdoor heat exchanger 23, the expansion mechanisms 24 and 26 and the indoor heat exchanger 41 in the cooling operation mode, The indoor heat exchanger 41, the expansion mechanisms 26 and 24, and the outdoor heat exchanger 23 in this order. Here, the indoor heat exchanger 41 is a cross-fin type heat exchanger, and the outdoor heat exchanger 23 is a stack type heat exchanger. The expansion mechanism (24, 26) has an upstream side expansion mechanism for reducing the pressure of the refrigerant and a downstream side expansion mechanism for reducing the pressure of the refrigerant depressurized in the upstream side expansion mechanism. Between the upstream side expansion mechanism and the downstream side expansion mechanism, And a refrigerant storage tank (25) for storing the refrigerant decompressed by the upstream expansion mechanism is provided.

Description

REFRIGERATION DEVICE

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a refrigerating device, particularly a refrigerating device capable of performing a cooling operation and a heating operation.

In the conventional refrigeration apparatus such as an air conditioner capable of cooling and heating operation, the optimum amount of refrigerant at cooling operation (cooling operation) differs from the optimal amount of refrigerant at the time of heating operation (heating operation). As a result, the volume of the outdoor heat exchanger functioning as a radiator during the cooling operation differs from the volume of the indoor heat exchanger functioning as a radiator during the heating operation. Normally, since the volume of the outdoor heat exchanger is larger than that of the indoor heat exchanger, the refrigerant that is not received in the indoor heat exchanger during the heating operation is temporarily stored by the refrigerant storage tank or the like connected to the suction side of the compressor.

Japanese Unexamined Patent Application Publication No. 6-143991

However, when the high-performance radiator described in Patent Document 1 (Japanese Patent Application Laid-open No. Hei 6-143991) is used as the outdoor heat exchanger in the refrigerating machine, the volume of the outdoor heat exchanger is less than the volume of the indoor heat exchanger do. In this case, in this case, the refrigerant (surplus refrigerant) that can not be received in the outdoor heat exchanger during the cooling operation is generated, and the amount exceeds the amount that can be stored in the refrigerant storage tank or the like.

An object of the present invention is to provide a refrigerating device capable of performing a cooling operation and a heating operation so that when the volume of the outdoor heat exchanger is less than the capacity of the indoor heat exchanger, have.

In the refrigeration apparatus according to the first aspect, the refrigerant flows in the order of the compressor, the outdoor heat exchanger, the expansion mechanism, and the indoor heat exchanger in the cooling operation, and in the order of the compressor, the indoor heat exchanger, the expansion mechanism, and the outdoor heat exchanger In which the refrigerant flows. In this refrigeration apparatus, the indoor heat exchanger is a cross-fin type heat exchanger, and the outdoor heat exchanger is a stack type heat exchanger. Further, the expansion mechanism has an upstream-side expansion mechanism for reducing the pressure of the refrigerant and a downstream-side expansion mechanism for reducing the pressure of the refrigerant depressurized in the upstream-side expansion mechanism. Between the upstream-side expansion mechanism and the downstream- And a refrigerant storage tank for storing the refrigerant decompressed by the expansion mechanism is provided.

The volume of the laminated heat exchanger is smaller than the volume of the cross-fin type heat exchanger having equivalent heat exchange performance. For example, it is assumed that the outdoor heat exchanger and the indoor heat exchanger are cross-fin type heat exchangers and that only the outdoor heat exchanger is changed to a stack heat exchanger having equivalent heat exchange performance. Then, the capacity of the stacked-type outdoor heat exchanger becomes smaller than the capacity of the cross-pinned outdoor heat exchanger, and becomes smaller than the capacity of the cross-finned indoor heat exchanger connected thereto.

Therefore, in this refrigeration apparatus, the capacity of the outdoor heat exchanger becomes smaller than the capacity of the indoor heat exchanger, so that surplus refrigerant is generated during the cooling operation. If this surplus refrigerant excessively spreads from the indoor heat exchanger having the vapor phase portion to the suction side of the compressor, the refrigerant control may be hindered.

Therefore, by providing the refrigerant storage tank for storing the refrigerant reduced in pressure by the upstream expansion mechanism between the upstream expansion mechanism and the downstream expansion mechanism, it is possible to prevent the excess refrigerant, which has not been accommodated in the outdoor heat exchanger, , And is housed in a refrigerant storage tank located in the vicinity of the downstream side of the outdoor heat exchanger.

Thus, in this refrigerating apparatus, it is possible to prevent the refrigerant from excessively spreading from the indoor heat exchanger having the gas phase portion to the suction side portion of the compressor, thereby preventing the refrigerant control from being hindered.

In the refrigeration apparatus according to the second aspect, the refrigerant flows in the order of the compressor, the outdoor heat exchanger, the expansion mechanism, and the indoor heat exchanger in the cooling operation, and in the order of the compressor, the indoor heat exchanger, the expansion mechanism, and the outdoor heat exchanger In which the refrigerant flows. In this refrigeration apparatus, the volume of the outdoor heat exchanger is 100% or less of the volume of the indoor heat exchanger. Further, the expansion mechanism has an upstream-side expansion mechanism for reducing the pressure of the refrigerant and a downstream-side expansion mechanism for reducing the pressure of the refrigerant depressurized in the upstream-side expansion mechanism. Between the upstream-side expansion mechanism and the downstream- And a refrigerant storage tank for storing the refrigerant decompressed by the expansion mechanism is provided.

When the volume of the outdoor heat exchanger becomes less than the capacity of the indoor heat exchanger, surplus refrigerant is generated during the cooling operation. If this surplus refrigerant excessively spreads from the indoor heat exchanger having the vapor phase portion to the suction side of the compressor, the refrigerant control may be hindered.

Therefore, by providing the refrigerant storage tank for storing the refrigerant reduced in pressure by the upstream expansion mechanism between the upstream expansion mechanism and the downstream expansion mechanism, it is possible to prevent the excess refrigerant, which has not been accommodated in the outdoor heat exchanger, , And is housed in a refrigerant storage tank located in the vicinity of the downstream side of the outdoor heat exchanger.

Thus, in this refrigerating apparatus, it is possible to prevent the refrigerant from excessively spreading from the indoor heat exchanger having the gas phase portion to the suction side portion of the compressor, thereby preventing the refrigerant control from being hindered.

A refrigerating apparatus according to a third aspect is the refrigerating apparatus according to the first or second aspect, wherein the refrigerant is R32.

If R32 is used as the refrigerant in the refrigerating machine, the solubility of the refrigerating machine oil sealed together with the refrigerant tends to be very small for the lubrication of the compressor under low temperature conditions. As a result, when the pressure becomes low in the refrigeration cycle, the solubility of the refrigerating machine oil is significantly lowered due to the lowering of the refrigerant temperature. Here, for example, in the conventional refrigeration apparatus having the refrigerant storage tank on the suction side of the compressor, if R32 is used as the refrigerant, the refrigerant and the refrigerant oil are separated into two layers in the refrigerant storage tank which becomes low pressure in the refrigeration cycle, It becomes difficult to return the refrigeration oil to the compressor.

However, in this refrigeration apparatus, as described above, since the refrigerant storage tank is provided between the upstream-side expansion mechanism and the downstream-side expansion mechanism, as compared with the case where the refrigerant storage tank is provided on the suction side of the compressor, It is easy to go back.

As described above, in this refrigeration apparatus, by providing the refrigerant storage tank between the upstream expansion mechanism and the downstream expansion mechanism, the volume of the outdoor heat exchanger is reduced by the use of a stacked-type heat exchanger as the outdoor heat exchanger, , It is possible to solve the problem of refrigerant return to the compressor caused by using R32 as the refrigerant.

In a refrigeration apparatus according to a fourth aspect, in the refrigeration system according to any one of the first to third aspects, the outdoor heat exchanger includes a plurality of flat tubes arranged so as to overlap with each other at intervals, Is a stacked-type heat exchanger.

In this refrigeration apparatus, since the capacity of the outdoor heat exchanger is equal to or less than the capacity of the indoor heat exchanger, the amount of refrigerant in the refrigeration apparatus is reduced, as in the refrigerating apparatuses according to the first to third aspects. Further, in this refrigeration apparatus, surplus refrigerant is generated during the cooling operation, but this surplus refrigerant can be accommodated in the refrigerant storage tank, thereby preventing the refrigerant from being hindered.

In a refrigeration apparatus according to a fifth aspect, in the refrigeration apparatus according to any one of the first to third aspects, the outdoor heat exchanger includes a plurality of flat tubes arranged so as to overlap with each other at intervals, Is a stacked heat exchanger having a fin.

In this refrigeration apparatus, since the capacity of the outdoor heat exchanger is equal to or less than the capacity of the indoor heat exchanger, the amount of refrigerant in the refrigeration apparatus is reduced, as in the refrigerating apparatuses according to the first to third aspects. Further, in this refrigeration apparatus, surplus refrigerant is generated during the cooling operation, but this surplus refrigerant can be accommodated in the refrigerant storage tank, thereby preventing the refrigerant from being hindered.

In a refrigeration apparatus according to a sixth aspect, in the refrigeration system according to any one of the first to third aspects, the outdoor heat exchanger includes a flat pipe formed in a meandering shape, and a pin inserted between adjacent surfaces of the flat pipe Is a stacked-type heat exchanger.

In this refrigeration apparatus, since the capacity of the outdoor heat exchanger is equal to or less than the capacity of the indoor heat exchanger, the amount of refrigerant in the refrigeration apparatus is reduced, as in the refrigerating apparatus according to the first or second aspect. Further, in this refrigeration apparatus, surplus refrigerant is generated during the cooling operation, but this surplus refrigerant can be accommodated in the refrigerant storage tank, thereby preventing the refrigerant from being hindered.

A refrigerating device according to a seventh aspect is the refrigerating device according to the second aspect, wherein the refrigerant is R32.

If R32 is used as the refrigerant in the refrigerating machine, the solubility of the refrigerating machine oil sealed together with the refrigerant tends to be very small for the lubrication of the compressor under low temperature conditions. As a result, when the pressure becomes low in the refrigeration cycle, the solubility of the refrigerating machine oil is significantly lowered due to the lowering of the refrigerant temperature. Here, for example, in the conventional refrigeration apparatus having the refrigerant storage tank on the suction side of the compressor, if R32 is used as the refrigerant, the refrigerant and the refrigerant oil are separated into two layers in the refrigerant storage tank which becomes low pressure in the refrigeration cycle, It becomes difficult to return the refrigeration oil to the compressor.

However, in this refrigeration apparatus, as described above, since the refrigerant storage tank is provided between the upstream-side expansion mechanism and the downstream-side expansion mechanism, as compared with the case where the refrigerant storage tank is provided on the suction side of the compressor, It is easy to go back.

Thus, in this refrigeration apparatus, by providing the refrigerant storage tank between the upstream expansion mechanism and the downstream expansion mechanism, not only the problem of the surplus refrigerant caused by the capacity of the outdoor heat exchanger being less than the capacity of the indoor heat exchanger, The problem of returning the refrigerant to the compressor caused by using R32 as the refrigerant can be solved.

According to an eighth aspect of the present invention, in the refrigeration system according to the second or seventh aspect, the outdoor heat exchanger and the indoor heat exchanger are cross-fin type heat exchangers, and the diameter of the heat transfer tube of the outdoor heat exchanger is larger than the diameter As shown in FIG.

In this refrigeration apparatus, since the capacity of the outdoor heat exchanger becomes equal to or less than the capacity of the indoor heat exchanger, the amount of refrigerant in the refrigeration apparatus is reduced, like the refrigeration apparatus according to the second aspect. Further, in this refrigeration apparatus, surplus refrigerant is generated during the cooling operation, but this surplus refrigerant can be accommodated in the refrigerant storage tank, thereby preventing the refrigerant from being hindered.

The refrigeration apparatus according to a ninth aspect is the refrigerating apparatus according to any one of the first to eighth aspects, further comprising a bypass pipe for guiding the gas component of the refrigerant stored in the refrigerant storage tank to the suction pipe of the compressor or the compressor .

In this refrigeration apparatus, the refrigerant decompressed in the upstream expansion mechanism is separated into a liquid component and a gas component in the refrigerant storage tank, and the gas component is directed to the bypass pipe.

Thus, in this refrigeration apparatus, the gas components not contributing to the evaporation do not flow into the outdoor heat exchanger functioning as the evaporator of the refrigerant during the heating operation, so that the refrigerant flowing through the outdoor heat exchanger functioning as the evaporator of the refrigerant It is possible to reduce the flow rate of the refrigerant and reduce the pressure loss in the refrigeration cycle.

A refrigeration apparatus according to a tenth aspect is the refrigeration apparatus according to the ninth aspect, wherein the bypass tube has a flow rate regulating mechanism.

When the operating frequency of the compressor is high, there is a possibility that the gas-liquid two-phase refrigerant from the refrigerant storage tank returns to the suction pipe of the compressor or the compressor through the bypass pipe and is sucked into the compressor.

However, in this refrigeration apparatus, since the flow rate adjusting mechanism is provided in the bypass pipe, the refrigerant liquid component in the vapor-liquid two-phase state is decompressed and evaporated.

Thus, in this refrigeration apparatus, the liquid component can be prevented from returning to the suction pipe of the compressor or the compressor.

Further, in this refrigeration apparatus, the refrigerant that has passed through the flow rate adjusting mechanism during the heating operation evaporates in the outdoor heat exchanger, and then joins the refrigerant toward the compressor or the suction pipe of the compressor. At this time, when the flow rate adjusting mechanism is an electrically operated expansion valve, the state of the refrigerant immediately before being sucked into the compressor can be adjusted more optimally by controlling the valve opening degree. In addition, since the flow rate of the refrigerant returned to the compressor can be increased or decreased by controlling the valve opening degree of the flow rate adjusting mechanism, the circulating flow rate of the refrigerant, that is, the flow rate of the refrigerant flowing through the indoor heat exchanger, can do.

An eleventh aspect of the refrigeration apparatus is the refrigerating apparatus according to any one of the first to tenth aspects, wherein the refrigerant storage tank is a gas-liquid separator.

In this refrigeration apparatus, the refrigerant storage tank including the gas-liquid separator is provided with both a function of reserving the liquid component and a function of separating the liquid component and the gas component.

Thus, in this refrigeration apparatus, there is no need to additionally provide a device having a refrigerant storage function and a device having a gas-liquid separation function, thereby contributing to the simplification of the device configuration.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram of an air conditioner as a refrigeration apparatus according to an embodiment of the present invention; FIG.
2 is a schematic front view of the indoor heat exchanger.
3 is an external perspective view of the outdoor heat exchanger.
4 is a graph showing the volume ratio of the outdoor heat exchanger capacity / indoor heat exchanger by capacity.
5 is a schematic sectional view of a refrigerant storage tank in Modification 1. Fig.
6 is an external perspective view of the outdoor heat exchanger in Modification 2. Fig.
7 is a longitudinal sectional view of the outdoor heat exchanger according to the second modification.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a refrigeration apparatus according to the present invention and modifications thereof will be described with reference to the drawings. The specific configuration of the refrigeration apparatus according to the present invention is not limited to the following embodiments and modifications thereof, and can be changed without departing from the gist of the invention.

(1) Configuration of air conditioner

1 is a schematic configuration diagram of an air conditioner 1 as a refrigeration apparatus according to an embodiment of the present invention.

The air conditioner (1) is a refrigeration apparatus capable of performing a cooling operation as a cooling operation and a heating operation as a heating operation by performing a vapor compression refrigeration cycle. The air conditioner 1 is mainly constituted by connecting an outdoor unit 2 and an indoor unit 4 to each other. Here, the outdoor unit 2 and the indoor unit 4 are connected via the liquid refrigerant communication pipe 5 and the gas refrigerant communication pipe 6. That is, the vapor compression refrigerant circuit 10 of the air conditioner 1 is constituted by connecting the outdoor unit 2 and the indoor unit 4 via the refrigerant communication pipes 5 and 6.

<Indoor unit>

The indoor unit (4) is installed in a room and constitutes a part of the refrigerant circuit (10). The indoor unit (4) mainly has an indoor heat exchanger (41).

The indoor heat exchanger (41) is a heat exchanger that functions as an evaporator of the refrigerant during the cooling operation to cool the room air, and functions as a radiator of the refrigerant during the heating operation to heat the room air. The liquid side of the indoor heat exchanger 41 is connected to the liquid refrigerant communication pipe 5 and the gas side of the indoor heat exchanger 41 is connected to the gas refrigerant communication pipe 6.

As shown in Fig. 2, the indoor heat exchanger 41 is a cross-fin type heat exchanger and mainly has a heat transfer fin 411 and a heat transfer pipe 412. [ 2 is a front view of the indoor heat exchanger 41. Fig. The heat conductive fins 411 are made of a thin aluminum plate, and the heat conductive fins 411 are formed with a plurality of through holes. The heat transfer tube 412 has a straight tube 412a inserted into the through hole of the heat transfer fin 411 and U-tubes 412b and 412c connecting the ends of the adjacent straight tube 412a. The straight pipe 412a is inserted into the through hole of the heat conductive fins 411 and then expanded to be in close contact with the heat conductive fins 411. [ The straight pipe 412a and the first U-shaped pipe 412b are formed integrally with each other. The second U-shaped pipe 412c is formed by integrally forming the straight pipe 412a in the through hole of the heat transfer fin 411, And is connected to the end of the straight pipe 411a by soldering or the like.

The indoor unit 4 has an indoor fan 42 for sucking indoor air into the indoor unit 4 and performing heat exchange with the refrigerant in the indoor heat exchanger 41 and then supplying the indoor air as the supply air have. Here, as the indoor fan 42, a centrifugal fan or multi-fan driven by the indoor fan motor 43 is used.

In addition, the indoor unit (4) has an indoor-side control unit (44) for controlling the operation of each unit constituting the indoor unit (4). The indoor-side control unit 44 has a microcomputer, a memory, and the like for controlling the indoor unit 4. The indoor-side control unit 44 performs a control signal or the like with a remote controller (not shown) The control signal and the like can be exchanged with the unit 2 via the transmission line 8a.

<Outdoor unit>

The outdoor unit (2) is installed outdoors and constitutes a part of the refrigerant circuit (10). The outdoor unit 2 mainly includes a compressor 21, a switching mechanism 22, an outdoor heat exchanger 23, a first expansion mechanism 24, a refrigerant storage tank 25, A liquid-side closing valve 27, and a gas-side closing valve 28. The liquid-

The compressor 21 is a device for compressing the low-pressure refrigerant in the refrigeration cycle until the pressure becomes high. The compressor 21 has an airtight structure for rotatably driving a displacement type compression element (not shown) such as a rotary type or a scroll type type by a compressor motor 21a controlled by an inverter. The compressor 21 has a suction pipe 31 connected to the suction side and a discharge pipe 32 connected to the discharge side. The suction pipe 31 connects the suction side of the compressor 21 and the first port 22a of the switching mechanism 22. In the suction pipe 31, an accumulator 29 is provided. The discharge pipe (32) is a refrigerant pipe connecting the discharge side of the compressor (21) and the second port (22b) of the switching mechanism (22).

The switching mechanism (22) is a mechanism for switching the direction of the refrigerant flow in the refrigerant circuit (10). The switching mechanism 22 functions as a radiator of the compressed refrigerant in the compressor 21 and functions as a radiator of the indoor heat exchanger 41 to the outdoor heat exchanger 23 So as to function as an evaporator of the heat-dissipated refrigerant. That is, the switching mechanism 22 allows the second port 22b and the third port 22c to communicate with each other and to switch the first port 22a and the fourth port 22d to communicate with each other . Thereby, the discharge side (here, the discharge pipe 32) of the compressor 21 and the gas side of the outdoor heat exchanger 23 (here, the first gas refrigerant pipe 33) are connected 22)). 1) is connected to the suction side of the compressor 21 (here, the suction pipe 31) and the side of the gas refrigerant communication pipe 6 (here, the second gas refrigerant pipe 34) See the solid line). The switching mechanism 22 also functions as the evaporator of the refrigerant that has been released in the indoor heat exchanger 41 and functions as the evaporator of the indoor heat exchanger 41 in the compressor 21 ) To function as a radiator of the compressed refrigerant. That is, the switching mechanism 22 switches the second port 22b and the fourth port 22d to communicate with each other and also to switch the first port 22a and the third port 22c to communicate with each other I do. 1) of the compressor 21 (here, the discharge pipe 32) is connected to the gas refrigerant communication pipe 6 side (here, the second gas refrigerant pipe 34) See the broken line in Fig. 1) of the compressor 21 is connected to the gas side of the outdoor heat exchanger 23 (here, the first gas refrigerant pipe 33) )). The first gas refrigerant pipe 33 is a refrigerant pipe which connects the third port 22c of the switching mechanism 22 and the gas side of the outdoor heat exchanger 23. The second gas refrigerant pipe 33 is a refrigerant pipe connecting the fourth port 22d of the switching mechanism 22 and the gas refrigerant communication pipe 6 side. Here, the switching mechanism 22 is a four-way switching valve.

The outdoor heat exchanger (23) is a heat exchanger which functions as a radiator of a refrigerant whose outdoor air serves as a cooling source during cooling operation and serves as a refrigerant evaporator which uses outdoor air as a heating source during heating operation. The liquid side of the outdoor heat exchanger (23) is connected to the liquid refrigerant pipe (35), and the gas side is connected to the first gas refrigerant pipe (33). The liquid refrigerant pipe (35) is a refrigerant pipe connecting the liquid side of the outdoor heat exchanger (23) and the side of the liquid refrigerant communication pipe (7).

The outdoor heat exchanger 23 is a stacked heat exchanger as shown in Fig. 3 and mainly has a flat pipe 231, a corrugated fin 232, and headers 233a and 233b. 3 is an external perspective view of the outdoor heat exchanger 23. Fig. The flat pipe 231 is formed of aluminum or an aluminum alloy and has a plane portion 231a serving as a heat transfer surface and a plurality of internal flow passages (not shown) through which the coolant flows. The flat pipe 231 is arranged in plural stages such that the flat pipe 231a overlaps with a space (ventilation space) in the state of facing up and down. The corrugated fin 232 is a pin made of aluminum or aluminum alloy bent in a corrugated shape. The corrugated fin 232 is disposed in a ventilation space sandwiched between vertically adjoining flat tubes 231 and the valley portion and the hill portion are in contact with the flat portion 231a of the flat tube 231. [ In addition, the valley portion and the mountain portion and the flat surface portion 231a are joined by soldering or the like. The headers 233a and 233b are connected to both ends of a flat pipe 231 arranged in plural stages in the vertical direction. The headers 233a and 233b have a function of supporting the flat pipe 231, a function of guiding the refrigerant to the internal flow path of the flat pipe 231, and a function of collecting the refrigerant coming from the internal flow path. When the outdoor heat exchanger 23 functions as a radiator of the refrigerant, the refrigerant flowing in from the first inlet 234 of the first header 233a flows through the respective inner channels of the uppermost flat pipe 231 almost equally And flows toward the second header 233b. The refrigerant reaching the second header 233b is evenly distributed to the respective internal flow passages of the second-stage flat pipe 231 and flows toward the first header 233a. Thereafter, the refrigerant in the odd-numbered stage flat pipe 231 flows toward the second header 233b, and the refrigerant in the even-numbered stage flat pipe 231 flows toward the first header 233a. The refrigerant in the lowermost stage flat tubes 231 flows toward the first header 233a and collects in the first header 233a and flows into the second inlet 235 of the first header 233a, Respectively. When the outdoor heat exchanger 23 functions as an evaporator of the refrigerant, the refrigerant flows in from the second inlet / outlet 235 of the first header 233a and flows into the flat pipe 231 and the headers 233a, 233b and then flows out from the first entrance 234 of the first header 233a. When the outdoor heat exchanger 23 functions as a radiator of the refrigerant, the refrigerant flowing in the flat pipe 231 radiates heat through the corrugated fin 232 to the air flow flowing through the ventilation space. When the outdoor heat exchanger 23 functions as an evaporator of the refrigerant, the refrigerant flowing in the flat pipe 231 absorbs heat from the air flow flowing through the air flow passage through the corrugated fin 232. Here, by using the above-described stacked type heat exchanger as the outdoor heat exchanger 23, the capacity of the outdoor heat exchanger 23 is made smaller than the capacity of the indoor heat exchanger 41. [ Regarding this point, the package air conditioner will be described with reference to Fig. 4 as an example. Here, FIG. 4 is a graph showing the volume ratio of the outdoor heat exchanger capacity / indoor heat exchanger by capacity. (Cross-pin type outdoor heat exchanger), package type air conditioner outdoor heat exchanger small-diameter type (laminated outdoor heat exchanger), and? Is room type air conditioner (cross-pin type outdoor heat exchanger ) And ▲ indicates an outdoor heat exchanger small-diameter type (laminated outdoor heat exchanger) of a room air-conditioner. 4, when the outdoor heat exchanger is changed to a laminated heat exchanger having the same heat exchange performance as compared to the case where both the outdoor heat exchanger and the indoor heat exchanger are cross-fin type heat exchangers, the volume ratio of the outdoor heat exchanger capacity / . This means that the capacity of the stacked type heat exchanger is not only smaller than the capacity of the cross-pin type outdoor heat exchanger but also smaller than the capacity of the cross-fin type indoor heat exchanger 41 connected thereto. As a result, in the air conditioner (1), surplus refrigerant is generated during the cooling operation. Therefore, in the air conditioner 1, the surplus refrigerant is contained in the refrigerant storage tank 25. [ 4, it is preferable to use the refrigerant storage tank 25 for storing surplus refrigerant when the outdoor heat exchanger capacity / indoor heat exchanger volume ratio is 0.3 to 0.9. However, it is preferable to use the refrigerant storage tank 25 having the outdoor heat exchanger capacity / indoor heat exchanger capacity ratio Is 1.0, stable refrigerant control becomes possible by using the refrigerant storage tank (25).

The first expansion mechanism 24 is a device that functions as an upstream expansion mechanism for reducing the refrigerant released in the outdoor heat exchanger 23 to the intermediate pressure in the refrigeration cycle during the cooling operation, In the heating operation, the mechanism 24 reduces the pressure of the refrigerant temporarily stored in the refrigerant storage tank 25 after the pressure is reduced in the second expansion mechanism 26 as the upstream expansion mechanism to the low pressure in the refrigeration cycle And functions as a side expansion mechanism. The first expansion mechanism (24) is provided in a portion of the liquid refrigerant pipe (35) close to the outdoor heat exchanger (23). Here, as the first expansion mechanism (24), a motor-operated expansion valve is used.

During the cooling operation, the second expansion mechanism (26) is configured such that the refrigerant temporarily stored in the refrigerant storage tank (25) after being depressurized by the first expansion mechanism (24) as the upstream expansion mechanism is lowered to the low pressure in the refrigeration cycle And functions as a downstream-side expansion mechanism for reducing pressure. The second expansion mechanism 26 is a device that functions as an upstream expansion mechanism for reducing the refrigerant released in the indoor heat exchanger 41 to the intermediate pressure in the refrigeration cycle during the heating operation. The second expansion mechanism (26) is provided in a portion of the liquid refrigerant pipe (35) close to the liquid side closing valve (27). Here, as the second expansion mechanism (26), a motor-operated expansion valve is used.

The refrigerant storage tank 25 is provided between the first expansion mechanism 24 and the second expansion mechanism 26 and includes a first expansion mechanism 24 or a second expansion mechanism 26 functioning as an upstream expansion mechanism ) As a surplus refrigerant can be stored. For example, when the amount of liquid refrigerant that can be accommodated in the indoor heat exchanger 41 is 1100 cc during the heating operation in which the indoor heat exchanger 41 functions as a radiator of the refrigerant, and the outdoor heat exchanger 23 functions as a radiator of the refrigerant The liquid refrigerant 300cc remaining in the outdoor heat exchanger 23 during the cooling operation is supplied to the refrigerant storage tank 25 ). For example, the refrigerant immediately before entering the refrigerant storage tank 25 contains a gas component generated when the pressure in the first expansion mechanism 24 or the second expansion mechanism 26, which functions as the upstream expansion mechanism, is reduced . Therefore, after entering the refrigerant storage tank 25, the refrigerant is separated into a liquid component and a gas component, and the liquid refrigerant is stored in the lower side and the gas refrigerant is stored in the upper side. The gas refrigerant separated from the refrigerant storage tank 25 flows to the suction pipe 31 of the compressor 21 through the bypass pipe 30. [ The liquid refrigerant separated from the refrigerant storage tank 25 is decompressed in the second expansion mechanism 26 functioning as the upstream expansion mechanism or the first expansion mechanism 24 and then supplied to the outdoor heat exchanger 23 Flows. Here, the bypass pipe 30 is provided so as to connect between the upper part of the refrigerant storage tank 25 and the part in the middle of the suction pipe 31. In the middle of the bypass pipe 30, a flow rate adjusting mechanism 30a is provided. In this case, a motor-operated expansion valve is used as the flow rate adjustment mechanism 30a. The outlet of the bypass pipe 30 may be connected directly to the compressor 21 instead of being connected to the part in the middle of the suction pipe 31. [

The liquid side shutoff valve 27 and the gas side shutoff valve 28 are valves provided in connection ports of external equipment and piping (specifically, the liquid refrigerant communication pipe 5 and the gas refrigerant communication pipe 6). The liquid-side shut-off valve 26 is provided at the end of the liquid refrigerant tube 35. The gas-side shut-off valve 27 is provided at the end of the second gas refrigerant pipe 34.

The outdoor unit 2 has an outdoor fan 36 for sucking outdoor air into the outdoor unit 2 and performing heat exchange with the refrigerant in the outdoor heat exchanger 23 and then discharging the outdoor air to the outside. Here, as the outdoor fan 36, a propeller fan or the like driven by the outdoor fan motor 37 is used.

The outdoor unit 2 also has an outdoor side control unit 38 for controlling the operation of each unit constituting the outdoor unit 2. The outdoor side control unit 38 has a microcomputer or a memory for controlling the outdoor unit 2 and is connected between the indoor side control unit 43 of the indoor unit 4 through the transmission line 8a Control signals and the like can be exchanged. That is to say, the control unit 8 for controlling the entire air conditioner 1 by the transmission line 8a connecting between the indoor side control unit 44 and the outdoor side control unit 38 and the control units 38 and 44 Consists of.

The control unit 8 is capable of controlling the operation of various devices and the valves 21a, 22, 24, 26, 30a, 37, 43 and the like based on various operation settings and detection values of various sensors.

<Refrigerant connector>

The refrigerant communication pipes 5 and 6 are refrigerant pipes that are installed locally when the air conditioner 1 is installed at a place such as a building or the like. It is used with various lengths or diameters.

As described above, the refrigerant circuit (10) of the air conditioner (1) is constituted by connecting the outdoor unit (2), the indoor unit (4) and the refrigerant communication pipes (5, 6). The refrigerant circuit 10 includes a compressor 21, an outdoor heat exchanger 23, a first expansion device 24 as an upstream expansion mechanism, a refrigerant storage tank 25, The refrigeration cycle in which the refrigerant flows in the order of the second expansion mechanism 26 as the mechanism and the indoor heat exchanger 41 is performed. The refrigerant circuit 10 includes a compressor 21, an indoor heat exchanger 41, a second expansion mechanism 26 as an upstream expansion mechanism, a refrigerant storage tank 25, The first expansion mechanism 24 as the side expansion mechanism, and the outdoor heat exchanger 23 in this order. The air conditioner 1 is capable of performing various operations such as cooling operation and heating operation by the control unit 8 including the indoor side control unit 44 and the outdoor side control unit 38. [

(2) Operation of the air conditioner

The air conditioner 1 can perform the cooling operation and the heating operation as described above. Hereinafter, the operation of the air conditioner 1 during the cooling operation and the heating operation will be described.

<Heating operation>

1, that is, when the second port 22b and the fourth port 22d communicate with each other and the first port 22a and the third port 22c ).

In this refrigerant circuit (10), the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor (21), compressed and discharged after being compressed to a high pressure.

The high pressure refrigerant discharged from the compressor 21 is sent to the indoor heat exchanger 41 through the switching mechanism 22, the gas side closing valve 28 and the gas refrigerant communication tube 6.

The high-pressure refrigerant sent to the indoor heat exchanger (41) exchanges heat with indoor air in the indoor heat exchanger (41) to dissipate heat. Thereby, the indoor air is heated. Since the capacity of the indoor heat exchanger 41 is larger than the capacity of the outdoor heat exchanger 23, most liquid refrigerant is contained in the indoor heat exchanger 41 during the heating operation.

The high-pressure refrigerant discharged from the indoor heat exchanger 41 is sent to the second expansion mechanism 26 functioning as the upstream expansion mechanism through the liquid refrigerant communication pipe 5 and the liquid side closing valve 27.

The refrigerant sent to the second expansion mechanism 26 is reduced to an intermediate pressure by the second expansion mechanism 26 and then sent to the refrigerant storage tank 25. The refrigerant immediately before entering the refrigerant storage tank 25 contains a gas component generated when the second expansion mechanism 26 is depressurized. However, after entering the refrigerant storage tank 25, the refrigerant is separated into a liquid component and a gas component So that the liquid refrigerant is stored at the lower side and the gas refrigerant is stored at the upper side. At this time, since the flow rate adjusting mechanism 30a of the bypass pipe 30 is controlled in the open state, the gas refrigerant in the refrigerant storage tank 25 flows through the bypass pipe 30, (31). The liquid refrigerant in the refrigerant storage tank 25 is reduced in pressure to a low pressure by the first expansion mechanism 24 as a downstream expansion mechanism and then sent to the outdoor heat exchanger 23.

The low-pressure refrigerant sent to the outdoor heat exchanger 23 performs heat exchange with the outdoor air supplied by the outdoor fan 36 in the outdoor heat exchanger 23 and evaporates. At this time, by the operation of sucking the gas refrigerant separating operation in the refrigerant storage tank 25 and the gaseous refrigerant separated through the bypass pipe 30 into the compressor 21, the refrigerant flowing into the outdoor heat exchanger 23 Respectively. As a result, the flow rate of the refrigerant flowing through the outdoor heat exchanger 23 is reduced, and the pressure loss can be reduced only by that amount, so that the pressure loss in the refrigeration cycle can be reduced.

The low-pressure refrigerant evaporated in the outdoor heat exchanger (23) is sucked into the compressor (21) again through the switching mechanism (22).

<Cooling operation>

1, that is, in a state in which the second port 22b and the third port 22c communicate with each other and the first port 22a and the fourth port 22d ).

In this refrigerant circuit (10), the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor (21), compressed and discharged after being compressed to a high pressure.

The high-pressure refrigerant discharged from the compressor (21) is sent to the outdoor heat exchanger (23) through the switching mechanism (22).

The high-pressure refrigerant sent to the outdoor heat exchanger (23) exchanges heat with the outdoor air in the outdoor heat exchanger (23) to radiate heat.

The high-pressure refrigerant that has been radiated by the outdoor heat exchanger 23 is sent to the first expansion mechanism 24 functioning as the upstream expansion mechanism and is depressurized to the intermediate pressure by the first expansion mechanism 24, , And is sent to the refrigerant storage tank (25). Here, since the capacity of the outdoor heat exchanger 23 is equal to or less than the capacity of the indoor heat exchanger 41, the outdoor heat exchanger 23 can not accommodate all the liquid refrigerant during the cooling operation. As a result, the liquid refrigerant that is not received in the outdoor heat exchanger 23 is stored in the refrigerant storage tank 25, and the refrigerant storage tank 25 is filled with the liquid refrigerant. The refrigerant immediately before entering the refrigerant storage tank 25 contains a gas component generated when the first expansion mechanism 24 is depressurized. However, after entering the refrigerant storage tank 25, the refrigerant is separated into a liquid component and a gas component So that the liquid refrigerant is stored at the lower side and the gas refrigerant is stored at the upper side. At this time, since the flow rate adjusting mechanism 30a of the bypass pipe 30 is controlled in the open state, the gas refrigerant in the refrigerant storage tank 25 flows through the bypass pipe 30, (31). The liquid refrigerant in the refrigerant storage tank 25 is depressurized to a low pressure by the second expansion mechanism 26 functioning as a downstream expansion mechanism and thereafter flows through the liquid side close valve 27 and the liquid refrigerant communication tube 5 And is sent to the heat exchanger (41).

The low-pressure refrigerant sent to the indoor heat exchanger (41) undergoes heat exchange with indoor air in the indoor heat exchanger (41) and evaporates. Thereby, the indoor air is cooled. At this time, by the operation of sucking the gas refrigerant separating operation in the refrigerant storage tank 25 and the gas refrigerant separated into the compressor 21 through the bypass pipe 30, the refrigerant flowing into the indoor heat exchanger 41 Respectively. As a result, the flow rate of the refrigerant flowing through the indoor heat exchanger (41) decreases, and the pressure loss can be reduced only by that amount, so that the reduced pressure loss in the refrigeration cycle can be reduced.

The low-pressure refrigerant evaporated in the indoor heat exchanger 51 is again sucked into the compressor 21 through the gas refrigerant communication pipe 6, the gas-side closing valve 28 and the switching mechanism 22.

(3) Characteristics of air conditioner

The air conditioner 1 of the present embodiment has the following features.

<A>

In the air conditioner 1, as described above, the indoor heat exchanger 41 is a cross-fin type heat exchanger, the outdoor heat exchanger 23 is a laminated heat exchanger, and the volume of the outdoor heat exchanger 23 is larger than that of the indoor heat exchanger 41). &Lt; / RTI &gt;

As a result, in the air conditioner 1, surplus refrigerant is generated during the cooling operation as the cooling operation. If this surplus refrigerant excessively spreads to a portion from the indoor heat exchanger 41 having the vapor phase portion to the suction side of the compressor 21, the refrigerant control may be hindered.

Therefore, in the air conditioner 1, the first expansion mechanism 24 and the second expansion mechanism 26 as the upstream-side expansion mechanism, the first expansion mechanism 24 as the downstream-side expansion mechanism, A refrigerant storage tank (25) for storing the refrigerant decompressed by the upstream expansion mechanism is provided between the other side of the second expansion mechanism (26). In the air conditioner 1, the surplus refrigerant that can not be accommodated in the outdoor heat exchanger 23 during the cooling operation is accommodated in the refrigerant storage tank 25 located in the vicinity of the downstream side of the outdoor heat exchanger 23 .

This makes it possible to prevent the air conditioner 1 from excessively spreading from the indoor heat exchanger 41 having the vapor phase portion to the suction side portion of the compressor 21, Can be prevented.

<B>

In the air conditioner 1, the bypass pipe 30 is provided as described above. The bypass pipe 30 guides the gas component of the refrigerant stored in the refrigerant storage tank 25 to the suction pipe 31 of the compressor 21 or the compressor 21.

In the air conditioner 1, the refrigerant decompressed in one of the first expansion mechanism 24 and the second expansion mechanism 26 as the upstream expansion mechanism is stored in the refrigerant storage tank 25 in the liquid component and the gas component And the gas component is directed to the bypass pipe 30. [

Thus, in the air conditioner 1, the gas component which does not contribute to evaporation does not flow into the outdoor heat exchanger 23, which functions as an evaporator of the refrigerant, during the heating operation. Therefore, The flow rate of the refrigerant flowing through the functioning outdoor heat exchanger 23 can be reduced, and the pressure reduction loss in the refrigeration cycle can be reduced.

<C>

The refrigerant in the gas-liquid two-phase state from the refrigerant storage tank 25 is returned to the compressor 21 or the suction pipe 31 of the compressor 21 through the bypass pipe 30 when the operation frequency of the compressor 21 is high, There is a possibility that the refrigerant is sucked into the compressor (21).

However, in the air conditioner 1, since the flow rate adjusting mechanism 30a is provided in the bypass pipe 30, the refrigerant liquid component in the vapor-liquid two-phase state is decompressed and evaporated.

Thereby, in the air conditioner 1, it is possible to prevent the liquid component from returning to the suction pipe 31 of the compressor 21 or the compressor 21.

<D>

In the air conditioner 1, the refrigerant having passed through the flow rate adjusting mechanism 30a is evaporated in the indoor heat exchanger 41 and the outdoor heat exchanger 23, Or to the refrigerant directed toward the suction pipe (31) of the compressor (21). At this time, when the flow rate adjusting mechanism 30a is a motor-operated expansion valve, the state of the refrigerant immediately before being sucked into the compressor 21 can be adjusted more optimally by controlling the valve opening degree. In addition, since the flow rate of the refrigerant returned to the compressor 21 can be increased or decreased by controlling the valve opening degree of the flow rate adjusting mechanism 30a, the circulating flow amount of the refrigerant can be increased or decreased according to the refrigerating load on the side of the indoor heat exchanger 41, The flow rate of the refrigerant flowing through the indoor heat exchanger 41 can be controlled.

(4) Modification 1

In the above embodiment, a container for storing the refrigerant is used as the refrigerant storage tank 25, but the present invention is not limited to this. For example, a cyclone-type gas-liquid separator as shown in Fig. 5 may be employed.

The refrigerant storage tank 25 of this modification mainly has a cylindrical container 251, a first connecting pipe 252, a second connecting pipe 253 and a third connecting pipe 254.

The first connecting pipe 252 is connected in the tangential direction of the circumferential side wall of the cylindrical container 251 and is connected to the inside of the cylindrical container 251 and the second expansion mechanism 26 as the downstream- (24). The second connecting pipe 253 is connected to the bottom wall of the cylindrical container 251 and is connected to the inside of the cylindrical container 251 and the first expansion mechanism 24 or the second expansion mechanism 26 as the upstream side expansion mechanism I am contacting you. The third connecting pipe 254 is connected to the upper wall of the cylindrical container 251 and communicates the inside of the cylindrical container 251 with the bypass pipe 30.

With such a configuration, the intermediate-pressure refrigerant flowing into the cylindrical container 251 through the first connecting pipe 252 flows like a swirl along the inner peripheral surface 251a of the circumferential side wall of the cylindrical container 251, Liquid refrigerant adheres to the inner circumferential surface 251a so that liquid refrigerant and gas refrigerant are efficiently separated.

The liquid refrigerant is dropped by gravity and stored in the lower side, and flows out of the cylindrical container 251 through the second connecting pipe 253. [ On the other hand, the gaseous refrigerant ascends while rotating, is stored in the upper side, and flows out of the cylindrical container 251 through the third connecting pipe 254.

As described above, in this modified example, since the cyclone type gas-liquid separator is employed as the refrigerant storage tank 25, the gas-liquid separation can be efficiently performed. The refrigerant storage tank 25 including the gas-liquid separator serves both as a refrigerant storage function for storing the liquid refrigerant and as a function for separating the liquid component and the gas component. As a result, the refrigerant storage tank 25 and the gas- So that it contributes to the simplification of the device configuration.

(5) Modification 2

In the above embodiment and Modification 1, a stacked heat exchanger in which the outdoor heat exchanger 23 has a plurality of flat tubes 231 and corrugated fins 232 is illustrated. The outdoor heat exchanger 23 is arranged so that a plurality of flat tubes 231 overlap with each other and the corrugated fin 232 is sandwiched between adjacent flat tubes 231.

However, the outdoor heat exchanger 23 is not limited to the configuration of the above-described embodiment and Modification 1. For example, as shown in Figs. 6 and 7, the outdoor heat exchanger 23 may include a plurality of flattened A stacked heat exchanger having a tube 231 and a fin 236 formed with a notch 236a into which the flat tube 231 is inserted may be used.

Even in this case, the same operation and effect as those of the above-described embodiment and modification 1 can be obtained.

(6) Modification 3

In the above embodiment and Modification 1, a stacked heat exchanger in which the outdoor heat exchanger 23 has a plurality of flat tubes 231 and corrugated fins 232 is illustrated. The outdoor heat exchanger 23 is arranged so that a plurality of flat tubes 231 overlap with each other and the corrugated fin 232 is sandwiched between adjacent flat tubes 231.

However, the outdoor heat exchanger 23 is not limited to the configuration of the above-described embodiment and Modification 1. For example, the outdoor heat exchanger 23 may be configured such that the flat pipe is formed in a meandering shape, and the fin is sandwiched between adjacent surfaces of the flat pipe .

Even in this case, the same operational effects as those of the above-described embodiment and Modifications 1 and 2 can be obtained.

(7) Variation 4

Although the outdoor heat exchanger 23 is a stacked heat exchanger having the plurality of flat tubes 231 and the fin 236 formed with the corrugation fins 232 and the notches 236a in the above embodiment and Modifications 1 to 3, But is not limited thereto. The outdoor heat exchanger 23 and the indoor heat exchanger 41 are both a cross fin type heat exchanger and the outdoor heat exchanger 23 is cooled by water, The diameter of the heat transfer pipe of the indoor heat exchanger 41 may be smaller than the diameter of the heat transfer pipe of the indoor heat exchanger 41. [

Even in this case, the same operational effects as those of the above-described embodiment and Modifications 1 to 3 can be obtained.

(8) Modification 5

In the above-described embodiment and Modifications 1 to 4, various refrigerants can be used as the refrigerant sealed in the refrigerant circuit 10. For example, R32, which is one type of HFC refrigerant, is used I think.

However, when R32 is used as the refrigerant in the refrigerating apparatus, the solubility of the refrigerating machine oil sealed together with the refrigerant tends to be very small for lubrication of the compressor 21 at low temperature. As a result, when the pressure becomes low in the refrigeration cycle, the solubility of the refrigerating machine oil is significantly lowered due to the lowering of the refrigerant temperature. In the refrigerant circuit 10, during the cooling operation, the refrigerant passes through the second expansion mechanism 26, which functions as the downstream expansion mechanism, until it is sucked into the compressor 21 via the indoor heat exchanger 41, The circuit portion of the refrigerant circuit becomes a low pressure in the refrigeration cycle. In the cooling operation, the circuit portion from the time after passing through the first expansion mechanism (24) functioning as the downstream side expansion mechanism to the time when it is sucked into the compressor (21) through the outdoor heat exchanger (23) Resulting in a low pressure in the cycle. In the case of using R32 as the refrigerant, an ether-based synthetic oil having some compatibility with R32, a mineral oil having an incompatibility with R32, an alkylbenzene-based synthetic oil, and the like are conceivable. In the ether-based synthetic oil, the compatibility is lost when the temperature is lowered to about -5 ° C. In mineral oil or alkylbenzene-based synthetic oil, it is not compatible with the ether-based synthetic oil even at higher temperatures. Here, for example, in the conventional refrigeration apparatus having the refrigerant storage tank on the suction side of the compressor, if R32 is used as the refrigerant, the refrigerant and the refrigerant oil are separated into two layers in the refrigerant storage tank which becomes low pressure in the refrigeration cycle, It becomes difficult to return the refrigeration oil to the compressor.

However, in the refrigeration apparatus 1 of the present modification, as described in the above-described embodiment and Modifications 1 to 4, between the first expansion mechanism (24, 26) as the upstream expansion mechanism and the downstream expansion mechanism Layer separation at the suction side of the compressor 21 is less likely to occur than in the case where the refrigerant storage tank is provided at the suction side of the compressor 21 and the compressor 21 ), It is easy to return the freezer oil.

As described above, in the refrigeration apparatus (1) of the present modification, the refrigerant storage tank (25) is provided between the first and second expansion mechanisms (24, 26) as the upstream side expansion mechanism and the downstream side expansion mechanism, Which is generated by using R32 as the refrigerant as well as the problem of the surplus refrigerant generated when the capacity of the outdoor heat exchanger 23 is less than the capacity of the indoor heat exchanger 41 by using a stacked heat exchanger as the compressor 23, 21 can be eliminated.

The present invention can be widely applied to a refrigeration apparatus capable of performing a cooling operation and a heating operation.

1: Air conditioner (freezer)
21: Compressor
23: outdoor heat exchanger
24, 26: expansion mechanism
25: Refrigerant storage tank
30: Bypass tube
30a:
41: indoor heat exchanger

Claims (11)

The refrigerant flows in the order of the compressor 21, the outdoor heat exchanger 23, the expansion mechanisms 24 and 26 and the indoor heat exchanger 41 in the cooling operation, and the refrigerant flows to the compressor, the indoor heat exchanger, The expansion mechanism, and the outdoor heat exchanger,
Wherein the indoor heat exchanger is a cross-fin type heat exchanger, the outdoor heat exchanger is a laminated type heat exchanger, the volume ratio of the outdoor heat exchanger to the indoor heat exchanger is 0.3 to 0.9,
Wherein the expansion mechanism includes an upstream expansion mechanism for reducing the pressure of the high-pressure refrigerant in the refrigeration cycle to an intermediate pressure in the refrigeration cycle, and an expansion valve for expanding the refrigerant of intermediate pressure in the reduced- And a downstream-side expansion mechanism for reducing the pressure to a low pressure in the cycle,
Wherein the outdoor heat exchanger, the upstream-side expansion mechanism, and the downstream-side expansion mechanism are installed in an outdoor unit (2), the indoor heat exchanger is installed in an indoor unit (4) (5)
The refrigerant is R32,
A refrigerant storage tank (25) is provided between the upstream side expansion mechanism and the downstream side expansion mechanism for storing the intermediate-pressure refrigerant in the refrigeration cycle decompressed by the upstream side expansion mechanism.
Wherein the refrigerant storage tank accommodates surplus refrigerant generated due to a volume of the outdoor heat exchanger being smaller than a volume of the indoor heat exchanger during the cooling operation. The refrigerant flows in the order of the compressor 21, the outdoor heat exchanger 23, the expansion mechanisms 24 and 26 and the indoor heat exchanger 41 in the cooling operation, and the refrigerant flows to the compressor, the indoor heat exchanger, The expansion mechanism, and the outdoor heat exchanger,
The volume of the outdoor heat exchanger is 30% to 90% of the volume of the indoor heat exchanger,
Wherein the expansion mechanism includes an upstream expansion mechanism for reducing the pressure of the high-pressure refrigerant in the refrigeration cycle to an intermediate pressure in the refrigeration cycle, and an expansion valve for expanding the refrigerant of intermediate pressure in the reduced- And a downstream-side expansion mechanism for reducing the pressure to a low pressure in the cycle,
Wherein the outdoor heat exchanger, the upstream-side expansion mechanism, and the downstream-side expansion mechanism are installed in an outdoor unit (2), the indoor heat exchanger is installed in an indoor unit (4) (5)
The refrigerant is R32,
A refrigerant storage tank (25) is provided between the upstream side expansion mechanism and the downstream side expansion mechanism for storing the intermediate-pressure refrigerant in the refrigeration cycle decompressed by the upstream side expansion mechanism.
Wherein the refrigerant storage tank accommodates surplus refrigerant generated due to a volume of the outdoor heat exchanger being smaller than a volume of the indoor heat exchanger during the cooling operation. 3. The method according to claim 1 or 2,
Wherein the outdoor heat exchanger (23) is a laminated heat exchanger having a plurality of flat tubes arranged so as to overlap with each other at intervals and fins sandwiched between adjacent flat tubes. 3. The method according to claim 1 or 2,
Wherein the outdoor heat exchanger (23) is a laminated heat exchanger having a plurality of flat tubes arranged so as to overlap with each other with intervals therebetween, and a fin formed with a notch into which the flat tubes are inserted. 3. The method according to claim 1 or 2,
Wherein the outdoor heat exchanger (23) is a laminated heat exchanger having a flat pipe formed in a meandering shape and fins sandwiched between adjacent surfaces of the flat pipe. 3. The method of claim 2,
The outdoor heat exchanger (23) and the indoor heat exchanger (41) are cross-fin type heat exchangers,
Wherein the diameter of the heat transfer pipe of the outdoor heat exchanger is set to be narrower than the diameter of the heat transfer pipe of the indoor heat exchanger. 3. The method according to claim 1 or 2,
Further comprising a bypass pipe (30) for guiding the gas component of the refrigerant stored in the refrigerant storage tank (25) to the compressor (21) or a refrigerant pipe on the suction side of the compressor. 8. The method of claim 7,
The bypass pipe (30) has a flow rate adjusting mechanism (30a). 3. The method according to claim 1 or 2,
The refrigerant storage tank (25) is a gas-liquid separator (1). delete delete

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