JP5708421B2 - Refrigeration equipment - Google Patents

Description

  The present invention relates to a refrigeration apparatus.

  2. Description of the Related Art Conventionally, a refrigeration apparatus that can change the rotation speed of a compressor with an inverter is known. In this apparatus, the amount of refrigerant circulating through the refrigeration cycle can be reduced by changing the rotation speed of the compressor according to the magnitude of the heat load.

  As a heat exchanger for a refrigeration apparatus, a heat exchanger shown in FIG. 3 and FIG. 17 of Patent Document 1 (Japanese Patent Laid-Open No. 10-267469) is known. In this heat exchanger, a plurality of refrigerant flow paths (hereinafter referred to as paths) are arranged in multiple stages in the vertical direction, and one end of each path and the flow divider are connected by a thin tube (hereinafter referred to as a capillary) called a capillary tube. It is. In many cases, the length of each capillary is determined so as not to cause a large difference in the amount of refrigerant flowing through each path in consideration of the pipe pressure loss (the amount of pressure loss in the pipe) of each path.

  In the refrigeration apparatus having a plurality of paths having different heights as described above and arranged in multiple stages and having a heat exchanger connected to the main flow path of the refrigerant by the flow divider and the capillary, the refrigerant circulation amount is small at low load Sometimes, the heat exchange efficiency may decrease. It is considered that when the refrigerant circulation amount decreases, the pressure loss of the refrigerant passing through each capillary decreases, and the drift due to the head difference of each path becomes relatively large. As a result, when the load is low, the liquid refrigerant stays in the path located in the lower part, and the heat exchange amount in the path decreases, so that the overall heat exchange efficiency is lowered or the circulating refrigerant quantity is insufficient. Sometimes.

  On the other hand, it is conceivable that the height position of the flow divider is lowered to suppress the uneven flow in each path of the heat exchanger at low load. However, this measure has the demerit that the housing size of the unit that accommodates the heat exchanger is increased and the device arrangement inside the unit is further restricted.

  The subject of this invention is providing the freezing apparatus which can suppress the fall of heat exchange efficiency also at the time of low load.

  The refrigeration apparatus according to the first aspect of the present invention includes a main refrigerant circuit and a supercooling refrigerant flow path. The main refrigerant circuit includes a compressor, a heat source side first heat exchanger that functions as a radiator, a first pressure reducer, and a use side heat exchanger that functions as an evaporator. The subcooling refrigerant flow path includes a heat source side second heat exchanger and a second pressure reducer that depressurizes the refrigerant cooled by the heat source side second heat exchanger. The supercooling refrigerant flow path cools the refrigerant flowing from the heat source side first heat exchanger to the utilization side heat exchanger with the refrigerant decompressed by the second decompressor. The first heat exchanger on the heat source side is formed with a plurality of paths that are a plurality of refrigerant flow paths having different heights. The main refrigerant circuit further includes a flow divider disposed between the heat source side first heat exchanger and the first pressure reducer, and a plurality of capillaries connecting the ends of the plurality of paths and the flow dividers. Yes. And the heat source side 1st heat exchanger is arrange | positioned above the heat source side 2nd heat exchanger.

  In this refrigeration apparatus, in the main refrigerant circuit, the refrigerant discharged from the compressor flows in order through the heat source side first heat exchanger, the first pressure reducer, and the use side heat exchanger, and is sucked into the compressor. A use-side heat exchanger that acts as an evaporator cools cooling objects such as room air. Further, the refrigerant cooled by the heat source side second heat exchanger of the supercooling refrigerant flow path and depressurized by the second pressure reducer cools the refrigerant flowing from the heat source side first heat exchanger to the user side heat exchanger. Thus, the degree of supercooling of the refrigerant flowing from the heat source side first heat exchanger to the use side heat exchanger is increased. Then, by arranging the heat source side first heat exchanger above the heat source side second heat exchanger, the current divider is arranged between the plurality of paths of the heat source side first heat exchanger and the first pressure reducer. Can be brought to a relatively low position. The flow divider and the plurality of paths of the heat source side first heat exchanger are connected by a plurality of capillaries. However, since the heat source side first heat exchanger is located above the heat source side second heat exchanger, for example, It is possible to arrange the heater at a height position where the second heat exchanger on the heat source side is located. In this case, even in a low-load operation, an event in which the refrigerant stays in the capillary connecting the flow path at the lowest position among the multiple paths of the heat source side first heat exchanger and the flow divider without overcoming the head difference. Hardly occurs, and the decrease in heat exchange efficiency can be reduced even at low loads. That is, in this refrigeration apparatus, the heat source side first heat exchanger of the main refrigerant circuit and the heat source side second heat exchanger of the subcooling refrigerant flow path are separated, and the heat source side first heat exchanger is used as the heat source side second heat exchanger. Since the arrangement is arranged above the exchanger, it becomes easy to lower the height position of the shunt, and the low-position path of the heat source side first heat exchanger is liquid-sealed at low load. This makes it easier to avoid problems.

  In the subcooling refrigerant flow path, the pressure difference between the inlet and the outlet of the heat source side second heat exchanger is larger than that of the heat source side first heat exchanger because the refrigerant is depressurized by the dedicated second pressure reducer. can do. Therefore, it is possible to suppress stagnation of the refrigerant in the heat source side second heat exchanger.

  The refrigeration apparatus according to the second aspect of the present invention is the refrigeration apparatus according to the first aspect, wherein the end portion at the lowest position among the end portions of the plurality of paths of the heat source side first heat exchanger is connected to the shunt. The capillary has a head difference of 200 mm or less between the portion at the highest position (hereinafter referred to as the highest point portion) and the connection portion between the ends of the path.

  In this refrigeration apparatus, the heat source side first heat exchanger of the main refrigerant circuit and the heat source side second heat exchanger of the supercooling refrigerant flow path are separated, and the heat source side first heat exchanger is replaced with the heat source side second heat exchanger. In the capillary connecting the end of the path at the lowest position of the first heat exchanger on the heat source side and the flow divider, the head difference between the highest point and the connection of the end of the path Can be made 200 mm or less. Thereby, even in low-load operation, it is possible to suppress an event in which the path of the heat source side first heat exchanger is liquid-sealed and the heat exchange efficiency is lowered.

  The refrigeration apparatus according to the third aspect of the present invention is the refrigeration apparatus according to the first aspect. Placed in position.

  In this refrigeration apparatus, the heat source side first heat exchanger of the main refrigerant circuit and the heat source side second heat exchanger of the supercooling refrigerant flow path are separated, and the heat source side first heat exchanger is replaced with the heat source side second heat exchanger. And the height position of the shunt is arranged at a low position as described above. Thereby, even in low-load operation, it is possible to suppress an event in which the path of the heat source side first heat exchanger is liquid-sealed and the heat exchange efficiency is lowered.

  The refrigeration apparatus according to the fourth aspect of the present invention is the refrigeration apparatus according to any one of the first to third aspects, wherein the main refrigerant circuit switches between cooling operation and heating operation by changing the direction of the flowing refrigerant. And a mechanism. In addition, the refrigeration apparatus according to the fourth aspect of the present invention further includes a heating refrigerant flow path. The heating refrigerant flow path causes the refrigerant to flow from the piping of the main refrigerant circuit on the refrigerant inflow side of the heat source side first heat exchanger to the heat source side second heat exchanger during the heating operation, and during the cooling operation, Stop the flow of refrigerant from the heat source side second heat exchanger to the piping of the main refrigerant circuit.

  In this refrigeration apparatus, the heating source side first heat exchanger performs the heating operation for flowing the refrigerant from the main refrigerant circuit pipe on the refrigerant inflow side of the heat source side first heat exchanger to the heat source side second heat exchanger by the heating refrigerant flow path. Not only the 1 heat exchanger but also the heat source side second heat exchanger can be used as an evaporator, and the heat exchange efficiency during the heating operation can be ensured. On the other hand, during cooling operation, in order to ensure the function of the supercooling refrigerant flow path for increasing the degree of supercooling of the refrigerant flowing from the heat source side first heat exchanger to the user side heat exchanger, The flow of the refrigerant from the exchanger to the main refrigerant circuit piping is stopped. In addition, interruption | blocking of the flow of the refrigerant | coolant from this heat source side 2nd heat exchanger to piping of the main refrigerant circuit is realizable by providing an electromagnetic on-off valve or a check valve in the refrigerant | coolant flow path for heating, for example.

  The refrigeration apparatus according to the fifth aspect of the present invention is the refrigeration apparatus according to any one of the first to fourth aspects, wherein the total volume of the refrigerant flow path formed in the heat source side second heat exchanger is the heat source side. It is 5 to 45% of the total volume of the refrigerant flow path formed in the first heat exchanger.

  In this refrigeration apparatus, by setting the capacity of the heat source side second heat exchanger as described above, the degree of supercooling of the refrigerant flowing from the heat source side first heat exchanger to the use side heat exchanger is set to an appropriate level. can do.

  A refrigeration apparatus according to a sixth aspect of the present invention is the refrigeration apparatus according to any one of the first to fifth aspects, wherein the heat source side first heat exchanger and the heat source side second heat exchanger are both cross fins. It is a tube-type heat exchanger and shares fins.

  In this refrigeration apparatus, the heat source side first heat exchanger of the main refrigerant circuit and the heat source side second heat exchanger of the supercooling refrigerant flow path are separated, and the heat source side first heat exchanger is replaced with the heat source side second heat exchanger. However, since the fins of both heat exchangers are shared, the cost is hardly increased compared to the case where several passes of one heat exchanger are used as subcooling passes.

  A refrigeration apparatus according to a seventh aspect of the present invention is the refrigeration apparatus according to any one of the first to fifth aspects, wherein the heat source side first heat exchanger and the heat source side second heat exchanger are both cross fins. It is a tube-type heat exchanger. And the fin of the heat source side 1st heat exchanger and the fin of the heat source side 2nd heat exchanger are provided separately.

  In this refrigeration apparatus, the heat source side first heat exchanger of the main refrigerant circuit and the heat source side second heat exchanger of the subcooling refrigerant flow path are separated from each other without sharing the fins. The optimal heat transfer tube size and fin shape can be selected.

  A refrigeration apparatus according to an eighth aspect of the present invention is the refrigeration apparatus according to any one of the first to seventh aspects, wherein the first pressure reducer and the second pressure reducer are expansion valves whose opening degrees can be adjusted respectively. . The refrigeration apparatus according to the eighth aspect of the present invention further includes a control unit that adjusts the opening of the first pressure reducer and the second pressure reducer. The control unit has a control mode for adjusting the opening of the second pressure reducer so that the flow rate of the refrigerant flowing through the heat source side second heat exchanger acting as a radiator is zero or small.

  In this refrigeration apparatus, the total heat exchange capacity of the heat source side first heat exchanger and the heat source side second heat exchanger is kept small in the cooling operation when the outside air temperature is low by executing the control mode. Can do. When the outside air is low, it tends to be difficult to ensure a high and low differential pressure, but it becomes easy to ensure the high and low differential pressure by suppressing the flow rate of the refrigerant flowing through the heat source side second heat exchanger by the control mode. . In other words, by using the above control mode, the lower limit value of the outside air temperature range in which the cooling operation can be performed can be lowered.

  In the refrigeration apparatus according to the first aspect of the present invention, since the heat source side first heat exchanger is disposed above the heat source side second heat exchanger, it becomes easy to lower the height position of the flow divider, and at low load However, the decrease in heat exchange efficiency can be minimized.

  In the refrigeration apparatus according to the second aspect or the third aspect of the present invention, even in a low-load operation, it is possible to suppress an event such that the path of the heat source side first heat exchanger is liquid-sealed and heat exchange efficiency is reduced. it can.

  In the refrigeration apparatus according to the fourth aspect of the present invention, not only the heat source side first heat exchanger but also the heat source side second heat exchanger can be used as an evaporator, and heat exchange efficiency during heating operation is ensured. Can do.

  In the refrigeration apparatus according to the fifth aspect of the present invention, the degree of supercooling of the refrigerant flowing from the heat source side first heat exchanger to the use side heat exchanger can be set to an appropriate level.

  In the refrigeration apparatus according to the sixth aspect of the present invention, since the fins of both heat exchangers are shared, when compared with the case where several paths of one heat exchanger are used as subcooling paths. Cost increase can be suppressed.

  In the refrigeration apparatus according to the seventh aspect of the present invention, since the fins are not shared by both heat exchangers, the optimum heat transfer tube size can be selected for each heat exchanger.

  In the refrigeration apparatus according to the eighth aspect of the present invention, the lower limit value of the outside air temperature range in which the cooling operation can be performed can be lowered.

The figure which shows the refrigerant | coolant piping system | strain of the air conditioning apparatus which concerns on one Embodiment of this invention. (A) The side view of an outdoor 1st heat exchanger, an outdoor 2nd heat exchanger, and a flow divider. (B) The figure which shows the path | pass of an outdoor 1st heat exchanger and an outdoor 2nd heat exchanger. The control block diagram of an air conditioning apparatus. (A) The side view of the conventional outdoor heat exchanger and a shunt. (B) The figure which shows the path | pass of the conventional outdoor heat exchanger. The figure which shows the refrigerant | coolant piping system | strain of the air conditioning apparatus which concerns on the modification A.

(1) Whole structure of air conditioning apparatus FIG. 1: has shown the refrigerant | coolant piping system | strain of the air conditioning apparatus 1 which is the freezing apparatus which concerns on one Embodiment of this invention. The air conditioner 1 is a distributed type air conditioner using a refrigerant piping system, and is an apparatus used for cooling and heating each room in a building by performing a vapor compression refrigeration cycle operation. The air conditioner 1 includes an outdoor unit 2 as a heat source unit, a plurality of indoor units 4 (in FIG. 1, two indoor units 4a and 4b), an outdoor unit 2 and an indoor unit 4 The first refrigerant communication pipe 6 and the second refrigerant communication pipe 7 are connected as refrigerant communication pipes. The main refrigerant circuit 10 of the air conditioner 1 is configured by connecting an outdoor unit 2, an indoor unit 4, and refrigerant communication tubes 6 and 7. The refrigerant is sealed in the main refrigerant circuit 10, and the refrigerant is compressed, cooled, depressurized, heated / evaporated, and compressed again as described later. It is like that. As the refrigerant, for example, one selected from R410A, R407C, R22, R134a, carbon dioxide, and the like is used.

(2) Detailed Configuration of Air Conditioner (2-1) Indoor Unit The indoor unit 4 is installed by being embedded or suspended in the ceiling of a room such as a building, or by wall hanging on the wall surface of the room. The indoor unit 4 is connected to the outdoor unit 2 via the refrigerant communication pipes 6 and 7 and constitutes a part of the main refrigerant circuit 10.

  Next, the configuration of the indoor unit 4 will be described. In FIG. 1, two indoor units 4a and 4b are shown as the indoor unit 4. However, since both indoor units 4 have the same configuration, only the configuration of the indoor unit 4a will be described here.

  The indoor unit 4 a has an indoor main refrigerant circuit 10 a that constitutes a part of the main refrigerant circuit 10. The indoor main refrigerant circuit 10a mainly includes an indoor expansion valve 41 that is a decompressor and an indoor heat exchanger 42 that is a use-side heat exchanger.

  The indoor expansion valve 41 is a mechanism for reducing the pressure of the refrigerant, and is an electric valve capable of adjusting the opening degree. The indoor expansion valve 41 has one end connected to the first refrigerant communication pipe 6 and the other end connected to the indoor heat exchanger 42.

  The indoor heat exchanger 42 is a heat exchanger that functions as a refrigerant heater or cooler. The indoor heat exchanger 42 has one end connected to the indoor expansion valve 41 and the other end connected to the second refrigerant communication tube 7.

  The indoor unit 4a is provided with an indoor fan 43 for sucking indoor air into the unit and supplying it to the room again, and exchanges heat between the indoor air and the refrigerant flowing through the indoor heat exchanger. The indoor fan 43 is rotationally driven by an indoor fan motor 43a.

  Various sensors are provided in the indoor unit 4a. Specifically, an indoor liquid pipe temperature sensor 44 and an indoor gas pipe temperature sensor 45 made of a thermistor are provided, and the temperature of the refrigerant pipe adjacent to the indoor heat exchanger 42 is measured. Furthermore, the indoor unit 4a has an indoor control unit 46 that controls the operation of each part constituting the indoor unit 4a. The indoor control unit 46 has a microcomputer, a memory, and the like provided for controlling the indoor unit 4a, and controls with a remote controller (not shown) for individually operating the indoor unit 4a. Exchange of a signal etc. is performed, and exchange of a control signal etc. is performed via the transmission line 8a with the outdoor control part 39 of the outdoor unit 2 mentioned later.

(2-2) Outdoor Unit The outdoor unit 2 is installed outside a building or the like, and is connected to the indoor units 4a and 4b via the first refrigerant communication pipe 6 and the second refrigerant communication pipe 7.

  Next, the configuration of the outdoor unit 2 will be described. The outdoor unit 2 includes an outdoor main refrigerant circuit 10c constituting a part of the main refrigerant circuit 10, a supercooling refrigerant flow path 12 used for increasing the degree of supercooling of the refrigerant in the cooling operation, and a heating operation. And a heating refrigerant passage 18 to be used. The outdoor main refrigerant circuit 10c mainly includes a compressor 21, a switching mechanism 22, an outdoor first heat exchanger 23, a first flow divider 25, an outdoor first expansion valve 26, and a liquid gas heat exchanger 27. A liquid side closing valve 28a, a gas side closing valve 28b, and an accumulator 29. The supercooling refrigerant channel 12 mainly includes an outdoor second heat exchanger 13, a second flow divider 14, and an outdoor second expansion valve 15. The heating refrigerant flow path 18 has an electromagnetic on-off valve 18a.

  The compressor 21 is a hermetic compressor driven by a compressor motor 21a. The number of the compressors 21 is only one in the present embodiment, but is not limited to this, and two or more compressors may be connected in parallel according to the number of indoor units 4 connected.

  The switching mechanism 22 is a mechanism for switching the direction of the refrigerant flow. During the cooling operation, the outdoor first heat exchanger 23 functions as a radiator for the refrigerant compressed by the compressor 21, and the indoor heat exchanger 42 is the refrigerant evaporator cooled in the outdoor first heat exchanger 23. To function as. For this purpose, the switching mechanism 22 connects the refrigerant pipe on the discharge side of the compressor 21 and one end of the outdoor first heat exchanger 23, and closes the compressor suction side pipe 29a (including the accumulator 29) and the gas side closure. The valve 28b is connected (see the solid line of the switching mechanism 22 in FIG. 1). Further, the switching mechanism 22 causes the indoor heat exchanger 42 to function as a radiator for the refrigerant compressed by the compressor 21 during the heating operation, and the outdoor first heat exchanger 23 is cooled in the indoor heat exchanger 42. It functions as a refrigerant evaporator. For this purpose, the switching mechanism 22 connects the refrigerant pipe on the discharge side of the compressor 21 and the gas side shut-off valve 28b, and connects the compressor suction side pipe 29a and one end of the outdoor first heat exchanger 23. (Refer to the broken line of the switching mechanism 22 in FIG. 1). In the present embodiment, the switching mechanism 22 is a four-way switching valve connected to the compressor suction side piping 29a, the discharge side refrigerant piping of the compressor 21, the outdoor first heat exchanger 23, and the gas side closing valve 28b. . The switching mechanism 22 is not limited to a four-way switching valve, and is configured to have a function of switching the refrigerant flow direction similar to that described above, for example, by combining a plurality of electromagnetic valves. There may be.

  The outdoor first heat exchanger 23 is a heat exchanger that functions as a refrigerant radiator or an evaporator (heater). One end of the outdoor first heat exchanger 23 is connected to the switching mechanism 22, and the other end is connected to the outdoor first expansion valve 26 via the first flow divider 25. The outdoor first heat exchanger 23 shares the gas refrigerant header 19 with the outdoor second heat exchanger 13, and the detailed configuration will be described later.

  The outdoor unit 2 has an outdoor fan 30 for sucking outdoor air into the unit and discharging it to the outdoor again. The outdoor fan 30 exchanges heat between the outdoor air and the refrigerant flowing through the outdoor first heat exchanger 23 and the outdoor second heat exchanger 13. The heat source of the outdoor first heat exchanger 23 and the outdoor second heat exchanger 13 is not limited to outdoor air, and may be another heat medium such as water.

  The outdoor first expansion valve 26 is a mechanism for decompressing the refrigerant in the main refrigerant circuit 10 and is an electric valve capable of adjusting the opening degree. One end of the outdoor first expansion valve 26 is connected to the outdoor first heat exchanger 23, and the other end is connected to the liquid side closing valve 28 a via the liquid gas heat exchanger 27.

  The liquid side closing valve 28 a is a valve to which the first refrigerant communication pipe 6 for exchanging refrigerant between the outdoor unit 2 and the indoor unit 4 is connected, and is connected to the outdoor first expansion valve 26. The gas-side closing valve 28 b is a valve to which the second refrigerant communication pipe 7 for exchanging refrigerant between the outdoor unit 2 and the indoor unit 4 is connected, and is connected to the switching mechanism 22. Here, the liquid side closing valve 28a and the gas side closing valve 28b are three-way valves provided with service ports.

  The accumulator 29 is disposed in a compressor suction side pipe 29 a between the switching mechanism 22 and the compressor 21.

  As will be described later, the outdoor second heat exchanger 13 provided in the subcooling refrigerant flow path 12 shares the gas refrigerant header 19 on the gas refrigerant inflow side in the cooling operation with the outdoor first heat exchanger 23. Yes. The outdoor second heat exchanger 13 is a heat exchanger that functions as a refrigerant radiator or evaporator (heater), one end of which is connected to the switching mechanism 22, and the other end to the outdoor second expansion valve 15. It is connected.

  The outdoor second expansion valve 15 is a mechanism for depressurizing the refrigerant in the subcooling refrigerant flow path 12, and is an electric valve capable of adjusting the opening degree. One end of the outdoor second expansion valve 15 is connected to the outdoor second heat exchanger 13 via the second flow divider 14, and the other end is connected to the outlet pipe 16 of the supercooling refrigerant channel 12. The outlet pipe 16 of the supercooling refrigerant flow path 12 passes through the liquid gas heat exchanger 27 from the outdoor second expansion valve 15 to the compressor suction side pipe 29a between the switching mechanism 22 and the accumulator 29. It is.

  The liquid gas heat exchanger 27 includes a refrigerant that flows in the main refrigerant circuit 10 from the outdoor first heat exchanger 23 toward the indoor unit 4, and a supercooling refrigerant channel 12 that passes from the outdoor second expansion valve 15 to the compressor suction side. The heat exchanger has a double-pipe structure that allows heat exchange with the refrigerant flowing into the pipe 29a. By this heat exchange, the liquid gas heat exchanger 27 further cools the refrigerant condensed in the outdoor first heat exchanger 23 during the cooling operation, and increases the degree of supercooling of the refrigerant toward the indoor unit 4.

  During the heating operation, the heating refrigerant flow path 18 branches the refrigerant from the pipe 10c1 of the main refrigerant circuit 10 on the refrigerant inflow side of the outdoor first heat exchanger 23, and adds to the outdoor first heat exchanger 23 and the outdoor. This is a refrigerant flow path for allowing the refrigerant to flow also to the second heat exchanger 13. This heating refrigerant flow path 18 is provided with an electromagnetic on-off valve 18a. The electromagnetic on-off valve 18a is opened during heating operation and closed during cooling operation.

  The outdoor unit 2 is provided with various sensors. The refrigerant pipe on the discharge side of the compressor 21 is provided with a discharge pressure sensor 31 that detects the compressor discharge pressure and a discharge temperature sensor 32 that detects the compressor discharge temperature. The compressor suction side pipe 29a is provided with a suction temperature sensor 33 for detecting the temperature of the gas refrigerant sucked into the compressor 21 and a suction pressure sensor 38 for detecting the compressor suction pressure. An outdoor first liquid pipe temperature sensor 35 that detects the temperature of the refrigerant is provided between the outdoor first heat exchanger 23 and the outdoor first expansion valve 26. An outdoor second liquid pipe temperature sensor 36 for detecting the temperature of the refrigerant is provided between the liquid gas heat exchanger 27 and the liquid side closing valve 28a. A temperature sensor 37 for detecting the temperature of the refrigerant is provided at the outlet pipe 16 of the refrigerant flow path 12 for supercooling from the liquid gas heat exchanger 27 to the low-pressure refrigerant pipe between the switching mechanism 22 and the accumulator 29. ing. The outdoor unit 2 is also provided with an outdoor temperature sensor 34 that detects the temperature of the outdoor air supplied to the outdoor first heat exchanger 23 and the outdoor second heat exchanger 13 by the outdoor fan 30. Each temperature sensor 32-37 consists of a thermistor. Further, the outdoor unit 2 has an outdoor control unit 39 that controls the operation of each part constituting the outdoor unit 2. The outdoor control unit 39 includes a microcomputer, a memory, and the like provided for controlling the outdoor unit 2. The outdoor control unit 39 communicates with the indoor control unit 46 of the indoor unit 4 through a transmission line 8 a. Exchange. As will be described later, the outdoor control unit 39 and the indoor control unit 46 constitute a control unit 8.

  Next, with reference to FIG. 2, the detailed structure of the outdoor 1st heat exchanger 23 and the outdoor 2nd heat exchanger 13 is demonstrated.

  The outdoor first heat exchanger 23 and the outdoor second heat exchanger 13 are both cross fin tube type heat exchangers, and the gas refrigerant header 19 on the refrigerant inflow side when acting as a radiator (condenser) in the cooling operation. Share heat dissipation fins. The outdoor second heat exchanger 13 that flows the supercooling refrigerant during the cooling operation has a total volume of the refrigerant flow path of 5 to 45 of the total volume of the refrigerant flow path formed in the outdoor first heat exchanger 23. % (15 to 20% in this embodiment). The smaller outdoor second heat exchanger 13 is disposed below the larger outdoor first heat exchanger 23.

  The outdoor first heat exchanger 23 is formed with a plurality of paths 23a, 23b, 23c,... That are a plurality of refrigerant flow paths having different heights. One end of each path 23a, 23b, 23c, ... is connected to the gas refrigerant header 19, and the other end of each path 23a, 23b, 23c, ... is connected to the first shunt 25 via the capillary 24. It is connected. Each capillary 24 is a small tube having a small diameter and is bent halfway as shown in FIG. The first shunt 25 is arranged at a position lower than the end 23a1 at the lowest position among the ends of the plurality of paths 23a, 23b, 23c,. As a result, the capillary 24a connected to the path 23a at the lowest position among the plurality of paths 23a, 23b, 23c,... Is directed upward from the end 23a1 of the path 23a, but is folded at a relatively low position. It is connected to the first shunt 25. Thereby, end part 23a1 in the lowest position among the end parts by the side of the 1st current divider 25 of a plurality of paths 23a, 23b, 23c, ... of outdoor 1st heat exchanger 23, and 1st current divider 25 2A, the head difference H1 between the portion 24a2 at the highest position and the connecting portion 24a1 between the end 23a1 of the path 23a is 200 mm or less, as shown in FIG.

  The outdoor second heat exchanger 13 also has a plurality of paths, but these paths are at a position lower than the path 23 a at the lowest position of the outdoor first heat exchanger 23. One end of the path of these outdoor second heat exchangers 13 is connected to the gas refrigerant header 19, and the other end is connected to the second flow divider 14.

(2-3) Refrigerant communication pipes The refrigerant communication pipes 6 and 7 are refrigerant pipes constructed on site when the outdoor unit 2 and the indoor unit 4 are installed at the installation location. In the present embodiment, the first refrigerant communication pipe 6 is connected to the outdoor unit 2 and the indoor units 4a and 4b, and during the cooling operation, the liquid refrigerant whose degree of supercooling is increased in the liquid gas heat exchanger 27 is indoors. A refrigerant pipe that is sent to the expansion valve 41 and the indoor heat exchanger 42 and sends the liquid refrigerant condensed in the indoor heat exchanger 42 to the outdoor first heat exchanger 23 and the outdoor second heat exchanger 13 of the outdoor unit 2 during heating operation. It is. The second refrigerant communication pipe 7 is connected to the outdoor unit 2 and the indoor units 4a and 4b. During the cooling operation, the gas refrigerant evaporated in the indoor heat exchanger 42 is sent to the compressor 21 of the outdoor unit 2 to perform the heating operation. Sometimes it is a refrigerant pipe that sends the gas refrigerant compressed in the compressor 21 to the indoor heat exchanger 42 of the indoor units 4a, 4b.

  As described above, the main refrigerant circuit 10 is configured by connecting the indoor main refrigerant circuit 10a, the outdoor main refrigerant circuit 10c, and the refrigerant communication pipes 6 and 7. Further, in the outdoor unit 2, a supercooling refrigerant flow path 12 is provided separately from the main refrigerant circuit 10, and a part of the refrigerant branched from the discharge side piping of the compressor 21 of the main refrigerant circuit 10 is provided during cooling operation. The second outdoor heat exchanger 13, the second outdoor expansion valve 15, and the liquid gas heat exchanger 27 flow in this order, and are returned to the front portion of the accumulator 29 in the suction side piping of the compressor 21.

(2-4) Control Unit FIG. 3 shows a control block diagram of the air conditioner 1. The control part 8 as a control means which performs various operation control of the air conditioning apparatus 1 is comprised by the outdoor control part 39 and the indoor control part 46 which are connected via the transmission line 8a, as shown in FIG. The control unit 8 receives the detection signals of the various sensors 31 to 38, 44, and 45, and controls the various devices 30, 26, 15, 21, 18a, 43, and 41 based on these detection signals and the like.

  The control unit 8 includes, as function units, a test operation control unit 91 for test operation and a normal operation control unit 92 for controlling normal operation such as cooling operation. The normal operation control unit 92 has a low outside air cooling mode 92a that is a control mode provided to ensure a high and low differential pressure when the outside air temperature is low.

(3) Operation | movement of an air conditioning apparatus Next, operation | movement of the air conditioning apparatus 1 which concerns on this embodiment is demonstrated. Control in various operations described below is performed by the control unit 8.

(3-1) Operation of cooling operation The cooling operation is performed by the normal operation control unit 92 of the control unit 8. During the cooling operation, the switching mechanism 22 is in the state indicated by the solid line in FIG. 1, that is, the discharged gas refrigerant from the compressor 21 flows to the outdoor first heat exchanger 23 and the outdoor second heat exchanger 13 and is compressed. The machine suction side pipe 29a is connected to the gas side closing valve 28b. The outdoor first expansion valve 26 is fully opened, and the opening degree of the indoor expansion valve 41 is adjusted. Further, the opening degree of the outdoor second expansion valve 15 of the supercooling refrigerant channel 12 is also adjusted. The electromagnetic on-off valve 18a of the heating refrigerant passage 18 is closed. The closing valves 28a and 28b are in an open state.

  In this state of the refrigerant circuit, the high-pressure gas refrigerant discharged from the compressor 21 passes through the switching mechanism 22 to the outdoor first heat exchanger 23 that functions as a refrigerant radiator in the main refrigerant circuit 10. It is sent and cooled by exchanging heat with the outdoor air supplied by the outdoor fan 30. The high-pressure refrigerant cooled and liquefied in the outdoor first heat exchanger 23 is sent to each indoor unit 4 via the outdoor first expansion valve 26 and the first refrigerant communication pipe 6. On the other hand, the high-pressure gas refrigerant discharged from the compressor 21 also flows to the outdoor second heat exchanger 13 of the supercooling refrigerant flow path 12 in parallel with the outdoor first heat exchanger 23 of the main refrigerant circuit 10. It cools by exchanging heat with outdoor air supplied by the fan 30. The liquid refrigerant exiting the outdoor second heat exchanger 13 is decompressed by the outdoor second expansion valve 15 and cools the refrigerant flowing through the main refrigerant circuit 10 in the liquid gas heat exchanger 27. Thereby, the degree of supercooling of the refrigerant flowing through the main refrigerant circuit 10 from the outdoor first heat exchanger 23 toward the indoor unit 4 is increased. The gas refrigerant that has flowed through the supercooling refrigerant flow path 12 and evaporated to a low pressure in the liquid gas heat exchanger 27 passes through the outlet pipe 16 of the supercooling refrigerant flow path 12 and the accumulator 29 and is sucked into the compressor 21. It is returned to the mouth. The refrigerant flowing through the main refrigerant circuit 10 and sent to each indoor unit 4 is decompressed by the indoor expansion valve 41 to become a low-pressure gas-liquid two-phase refrigerant, and the indoor heat exchanger 42 functions as a refrigerant evaporator. Heat exchange with room air and evaporate into a low-pressure gas refrigerant. Then, the low-pressure gas refrigerant heated in the indoor heat exchanger 42 is sent to the outdoor unit 2 via the second refrigerant communication pipe 7, and again sucked into the compressor 21 via the switching mechanism 22. In this way, the room is cooled.

  In the cooling operation, when the outside air temperature becomes very low, the normal operation control unit 92 of the control unit 8 continues the cooling operation using the low outside air cooling mode 92a. In the low outside air cooling mode 92a, the outdoor second expansion valve 15 whose opening has been adjusted is closed so that almost no refrigerant flows into the supercooling refrigerant flow path 12. Thereby, even at the time of low outside air, the difference between the high pressure and the low pressure can be secured and the operation can be continued. In the cooling operation, the high pressure is a representative value of the pressure of the refrigerant flowing from the compressor 21 to the outlet of the outdoor first heat exchanger 23 that functions as a refrigerant condenser. This is a representative value of the pressure of the refrigerant flowing from the outlet of the indoor expansion valve 41 to the compressor 21 via the indoor heat exchanger 42 functioning as a refrigerant evaporator.

(3-2) Operation of Heating Operation Heating operation is performed by the normal operation control unit 92 of the control unit 8. During the heating operation, the switching mechanism 22 is in the state indicated by the broken line in FIG. 1, that is, the refrigerant pipe on the discharge side of the compressor 21 is connected to the gas side shut-off valve 28b, and the compressor suction side pipe 29a is outdoor. The first heat exchanger 23 and the outdoor second heat exchanger 13 are connected. The opening degree of the outdoor first expansion valve 26 and the indoor expansion valve 41 is adjusted. The outdoor second expansion valve 15 is fully closed, and the electromagnetic on-off valve 18a of the heating refrigerant flow path 18 is opened. The closing valves 28a and 28b are in an open state.

  In the state of this refrigerant circuit, the high-pressure gas refrigerant discharged from the compressor 21 is sent to each indoor unit 4 via the switching mechanism 22 and the second refrigerant communication pipe 7. The high-pressure gas refrigerant sent to each indoor unit 4 passes through the indoor expansion valve 41 after being cooled by exchanging heat with indoor air in the indoor heat exchanger 42 functioning as a refrigerant radiator. Then, it is sent to the outdoor unit 2 via the first refrigerant communication pipe 6. The high-pressure refrigerant sent to the outdoor unit 2 is decompressed by the outdoor first expansion valve 26 to become a low-pressure gas-liquid two-phase refrigerant, and the outdoor first heat exchanger 23 and the outdoor functioning as a refrigerant evaporator. It flows into the second heat exchanger 13. The low-pressure gas-liquid two-phase refrigerant flowing into the outdoor first heat exchanger 23 and the outdoor second heat exchanger 13 is heated and evaporated by exchanging heat with the outdoor air supplied by the outdoor fan 30. It becomes a low-pressure refrigerant. The low-pressure gas refrigerant that has exited the first outdoor heat exchanger 23 and the second outdoor heat exchanger 13 is again sucked into the compressor 21 via the switching mechanism 22. In this way, the room is heated.

(4) Features (4-1)
In the air conditioner 1 according to the present embodiment, in the main refrigerant circuit 10, the refrigerant discharged from the compressor 21 sequentially flows through the outdoor first heat exchanger 23, the indoor expansion valve 41, and the indoor heat exchanger 42, and is compressed. By being sucked into the machine 21, the indoor heat exchanger 42 that functions as an evaporator cools the indoor air. In addition, the refrigerant that has been cooled by the outdoor second heat exchanger 13 and depressurized by the outdoor second expansion valve 15 in the supercooling refrigerant flow path 12 flows from the outdoor first heat exchanger 23 to the indoor heat exchanger 42. Is increased, the degree of supercooling of the refrigerant flowing from the outdoor first heat exchanger 23 to the indoor heat exchanger 42 is increased. And by arranging the outdoor first heat exchanger 23 above the outdoor second heat exchanger 13, a plurality of paths 23a, 23b, 23c,... The installation position of the first shunt 25 arranged between the two can be brought to a relatively low position. The plurality of paths 23a, 23b, 23c,... Of the first shunt 25 and the outdoor first heat exchanger 23 are connected by a plurality of capillaries 24. The outdoor first heat exchanger 23 is an outdoor second heat exchanger. Therefore, the first diverter 25 can be arranged at a height position where the outdoor second heat exchanger 13 is located (see FIG. 2A).

  For this reason, even in a low load operation, in the capillary 24a that connects the path 23a at the lowest position among the plurality of paths 23a, 23b, 23c... Of the outdoor first heat exchanger 23 and the first flow divider 25. The phenomenon that the refrigerant stays without exceeding the head difference H1 hardly occurs, and the decrease in heat exchange efficiency is reduced even at low loads.

  That is, in the air conditioner 1, the outdoor first heat exchanger 23 of the main refrigerant circuit 10 and the outdoor second heat exchanger 13 of the supercooling refrigerant flow path 12 are separated, and the outdoor first heat exchanger 23 is connected to the outdoor. Since the structure of arrange | positioning above the 2nd heat exchanger 13 is taken, it is easy to lower the height position of the 1st flow divider 25. FIG. And here, the 1st shunt 25 is made into the position lower than the edge part 23a1 in the lowest position among the edge parts of several path | pass 23a, 23b, 23c, ... of the outdoor 1st heat exchanger 23. FIG. It is arranged. Thereby, end part 23a1 in the lowest position among the end parts by the side of the 1st current divider 25 of a plurality of paths 23a, 23b, 23c, ... of outdoor 1st heat exchanger 23, and 1st current divider 25 2A, the head difference H1 between the portion 24a2 at the highest position and the connecting portion 24a1 between the end 23a1 of the path 23a is 200 mm or less, as shown in FIG.

  As described above, since the head difference H1 of the capillary 24a can be reduced, the most of the plurality of paths 23a, 23b, 23c,... The liquid refrigerant hardly stays in the path 23a located at a low position, and a decrease in heat exchange efficiency is suppressed.

  Further, in the subcooling refrigerant flow path 12, since the refrigerant is decompressed by the dedicated outdoor second expansion valve 15 different from the outdoor first expansion valve 26, the difference between the inlet and the outlet of the outdoor second heat exchanger 13. The pressure can be made larger than that of the outdoor first heat exchanger 23. Thereby, the residence of the refrigerant | coolant in the outdoor 2nd heat exchanger 13 can also be suppressed.

(4-2)
The outdoor heat exchanger 323 shown in FIG. 4 is a heat exchanger having the same capacity as the total capacity of the outdoor first heat exchanger 23 and the outdoor second heat exchanger 13 shown in FIG. It is a heat exchanger that adopts. The flow divider 325 is disposed at a considerably high position, and is connected to each path 323 a, 323 b, 323 c... Of the outdoor heat exchanger 323 via the capillary 324. The capillary 324a connected to the lowest path 323a among the plurality of paths 323a, 323b, 323c,... The dimensions are quite large. Of course, the head difference H2 can be reduced to some extent by lowering the height position of the flow divider 325. However, since the height position of the end of the path 323a is at a very low position, the air according to the present embodiment. It is difficult to reduce the head difference H1 (see FIG. 2) as in the harmony device 1 to a minimum.

(4-3)
In the air conditioner 1 according to the present embodiment, the refrigerant flows also from the pipe 10c1 of the main refrigerant circuit 10 on the refrigerant inflow side of the outdoor first heat exchanger 23 to the outdoor second heat exchanger 13 by the heating refrigerant flow path 18. Heating operation is performed. For this reason, not only the outdoor first heat exchanger 23 but also the outdoor second heat exchanger 13 can be used as an evaporator, and the heat exchange efficiency during the heating operation can be ensured.

  On the other hand, during the cooling operation, in order to ensure the function of the supercooling refrigerant flow path 12 to increase the degree of supercooling of the refrigerant flowing through the main refrigerant circuit 10 from the outdoor first heat exchanger 23 to the indoor heat exchanger 42. The flow of the refrigerant from the outdoor second heat exchanger 13 to the pipe 10c1 of the main refrigerant circuit 10 is stopped.

(4-4)
In the air conditioner 1 according to the present embodiment, the total volume of the refrigerant flow path of the outdoor second heat exchanger 13 through which the supercooling refrigerant flows during the cooling operation is used as the outdoor first heat exchanger 23 of the main refrigerant circuit 10. It is set to 5 to 45% of the total volume of the formed refrigerant flow path. By setting the capacity of the outdoor second heat exchanger 13 in this way, the degree of supercooling of the refrigerant flowing from the outdoor first heat exchanger 23 to the indoor heat exchanger 42 during the cooling operation can be set to an appropriate level. is made of.

(4-5)
In the air conditioner 1 according to the present embodiment, the outdoor first heat exchanger 23 of the main refrigerant circuit 10 and the outdoor second heat exchanger 13 of the subcooling refrigerant flow path 12 are separated, and the outdoor first heat exchanger 23 is separated. Is disposed above the second outdoor heat exchanger 13, but since both the heat exchangers 23 and 13 share the radiation fins, the paths 323a and 323b of one outdoor heat exchanger 323 shown in FIG. , 323c,..., 323c..., 323c.

(4-6)
In the air conditioning apparatus 1 according to the present embodiment, when the outside air temperature becomes very low during the cooling operation, the normal operation control unit 92 of the control unit 8 continues the cooling operation using the low outside air cooling mode 92a. . In other words, the outdoor second expansion valve 15 is closed so that the refrigerant hardly flows into the supercooling refrigerant flow path 12 to ensure the difference between the high pressure and the low pressure even in the low outside air. Thereby, in the air conditioning apparatus 1, the lower limit value of the outside air temperature range in which the cooling operation can be performed can be reduced.

(5) Modification (5-1) Modification A
In the above embodiment, the present invention is applied to the air conditioner 1 including the outdoor unit 2 including the switching mechanism 22 and capable of switching between the cooling operation and the heating operation. The present invention can also be applied.

  The air conditioner 101 shown in FIG. 5 includes an outdoor unit 102 as a heat source unit, a plurality of indoor units 4 as use units, and a first refrigerant as a refrigerant communication tube that connects the outdoor unit 102 and the indoor unit 4. A communication pipe 6 and a second refrigerant communication pipe 7 are provided. The main refrigerant circuit 110 of the air conditioner 101 is configured by connecting the outdoor unit 102, the indoor unit 4, and the refrigerant communication pipes 6 and 7.

  About the indoor unit 4, since it is the same as said embodiment, description is abbreviate | omitted.

  The outdoor unit 102 is connected to the indoor unit 4 via the first refrigerant communication pipe 6 and the second refrigerant communication pipe 7. The outdoor unit 102 includes an outdoor main refrigerant circuit 110c that constitutes a part of the main refrigerant circuit 110, and a supercooling refrigerant channel 112 that is used to increase the degree of supercooling of the refrigerant. The outdoor main refrigerant circuit 110c mainly includes a compressor 121, an outdoor first heat exchanger 23, a flow divider 25, a liquid gas heat exchanger 127, a liquid side closing valve 128a, and a gas side closing valve 128b. And an accumulator 129. The supercooling refrigerant channel 112 mainly includes the outdoor second heat exchanger 13 and the outdoor second expansion valve 115.

  The compressor 121 is a hermetic compressor driven by a compressor motor 121a.

  The outdoor first heat exchanger 23 is a heat exchanger that functions as a refrigerant radiator (condenser). One end of the outdoor first heat exchanger 23 is connected to the compressor 121, and the other end is connected to the liquid gas heat exchanger 127 via the capillary 24 and the flow divider 25. The outdoor first heat exchanger 23 shares the gas refrigerant header with the outdoor second heat exchanger 13.

  The outdoor unit 102 has an outdoor fan 130 for sucking outdoor air into the unit and discharging it to the outdoor again. The outdoor fan 130 exchanges heat between the outdoor air and the refrigerant flowing through the outdoor first heat exchanger 23 and the outdoor second heat exchanger 13.

  The liquid side closing valve 128 a is a valve to which the first refrigerant communication pipe 6 for exchanging refrigerant between the outdoor unit 102 and the indoor unit 4 is connected, and is connected to the liquid gas heat exchanger 127. The gas-side shutoff valve 128b is a valve to which the second refrigerant communication pipe 7 for exchanging refrigerant between the outdoor unit 102 and the indoor unit 4 is connected, and is connected to the refrigerant pipe (accumulator 129) on the suction side of the compressor 121. Connected).

  The outdoor second heat exchanger 13 provided in the supercooling refrigerant flow path 112 shares the gas refrigerant header on the gas refrigerant inflow side with the outdoor first heat exchanger 23. The outdoor second heat exchanger 13 is a heat exchanger that functions as a refrigerant radiator (condenser), one end of which is connected to the compressor 121 and the other end connected to the outdoor second expansion valve 115. Yes.

  The outdoor second expansion valve 115 is a mechanism for decompressing the refrigerant in the supercooling refrigerant flow path 112, and is an electric valve capable of adjusting the opening degree. The outdoor second expansion valve 115 has one end connected to the outdoor second heat exchanger 13 and the other end connected to the liquid gas heat exchanger 127. The refrigerant depressurized by the outdoor second expansion valve 115 passes through the liquid gas heat exchanger 127 and travels to the low-pressure refrigerant pipe between the gas-side closing valve 128b and the accumulator 129.

  The liquid gas heat exchanger 127 includes a refrigerant that flows in the main refrigerant circuit 110 from the outdoor first heat exchanger 23 toward the indoor unit 4, and a supercooling refrigerant flow path 112 from the outdoor second expansion valve 115 to the compressor 121. This is a heat exchanger having a double-pipe structure that exchanges heat with the refrigerant flowing to the refrigerant pipe on the suction side. The liquid gas heat exchanger 127 further cools the refrigerant condensed in the outdoor first heat exchanger 23 by this heat exchange, and increases the degree of supercooling of the refrigerant toward the indoor unit 4.

  Further, description of various sensors of the outdoor unit 102 is omitted.

  The outdoor unit 102 includes an outdoor control unit 139 that controls the operation of each unit constituting the outdoor unit 102. The outdoor control unit 139 exchanges control signals and the like with the indoor control unit 46 of the indoor unit 4 via the transmission line 8a. The outdoor control unit 139 and the indoor control unit 46 constitute a control unit 108.

  The detailed configurations of the outdoor first heat exchanger 23 and the outdoor second heat exchanger 13 are the same as those of the outdoor first heat exchanger 23 and the outdoor second heat exchanger 13 shown in FIG.

  The main refrigerant circuit 110 is configured by connecting the indoor main refrigerant circuit 10a, the outdoor main refrigerant circuit 110c, and the refrigerant communication pipes 6 and 7. Further, in the outdoor unit 102, a subcooling refrigerant flow path 112 is provided separately from the main refrigerant circuit 110, and during operation, a part of the refrigerant branched from the discharge side piping of the compressor 121 of the main refrigerant circuit 110 is The outdoor second heat exchanger 13, the outdoor second expansion valve 115, and the liquid gas heat exchanger 127 flow in this order, and are returned to the portion of the suction side piping of the compressor 121 before the accumulator 129.

  The high-pressure gas refrigerant discharged from the compressor 121 of the air conditioner 101 flows in parallel to the outdoor first heat exchanger 23 and the outdoor second heat exchanger 13. The refrigerant flowing through the outdoor first heat exchanger 23 functioning as a refrigerant radiator is cooled by exchanging heat with outdoor air supplied by the outdoor fan 130. The high-pressure refrigerant cooled and liquefied in the outdoor first heat exchanger 23 is sent to each indoor unit 4 via the liquid gas heat exchanger 127 and the first refrigerant communication pipe 6. On the other hand, the refrigerant flowing through the outdoor second heat exchanger 13 in the supercooling refrigerant flow path 112 is cooled by exchanging heat with outdoor air supplied by the outdoor fan 130. The liquid refrigerant exiting the outdoor second heat exchanger 13 is decompressed by the outdoor second expansion valve 115, and cools the refrigerant flowing through the main refrigerant circuit 110 in the liquid gas heat exchanger 127. As a result, the degree of supercooling of the refrigerant flowing through the main refrigerant circuit 110 from the outdoor first heat exchanger 23 toward the indoor unit 4 increases. The gas refrigerant that has flowed through the supercooling refrigerant channel 112 and evaporated to a low pressure in the liquid gas heat exchanger 127 is returned to the suction port of the compressor 121 via the accumulator 129. The refrigerant flowing through the main refrigerant circuit 110 and sent to each indoor unit 4 is decompressed by the indoor expansion valve 41 to become a low-pressure gas-liquid two-phase refrigerant, and functions as an evaporator for the indoor heat exchanger 42. Heat exchange with room air and evaporate into a low-pressure gas refrigerant. Then, the low-pressure gas refrigerant heated in the indoor heat exchanger 42 is sent to the outdoor unit 102 via the second refrigerant communication pipe 7 and sucked into the compressor 121 again. In this way, the room is cooled.

  Also in the air conditioner 101 shown in FIG. 5, the outdoor first heat exchanger 23 of the main refrigerant circuit 110 and the outdoor second heat exchanger 13 of the supercooling refrigerant flow path 112 are separated, and the outdoor first heat exchanger 23 is separated. Is disposed above the second outdoor heat exchanger 13, the height position of the flow divider 25 can be lowered. For this reason, even at the time of low load, the liquid refrigerant hardly stagnates in the lower path among the plurality of paths of the outdoor first heat exchanger 23, and deterioration of heat exchange efficiency is suppressed. .

(5-2) Modification B
In the air conditioner 1 according to the above embodiment, the outdoor first heat exchanger 23 of the main refrigerant circuit 10 and the outdoor second heat exchanger 13 of the subcooling refrigerant flow path 12 share the radiation fins. The heat radiating fins of both heat exchangers may be provided separately. In this case, in each heat exchanger, heat transfer tubes having different sizes can be selected, and the degree of freedom in design increases.

1 Air conditioning equipment (refrigeration equipment)
8 Control Unit 10 Main Refrigerant Circuit 12 Supercooling Refrigerant Flow Channel 13 Outdoor Second Heat Exchanger (Heat Source Side Second Heat Exchanger)
15 Outdoor second expansion valve (second decompressor)
18 Heating refrigerant flow path 21 Compressor 22 Switching mechanism 23 Outdoor first heat exchanger (heat source side first heat exchanger)
23a Path of the outdoor first heat exchanger 23a1 Ends 23b, 23c at the lowest position among the ends of the plurality of paths of the outdoor first heat exchanger Path 24 of the outdoor first heat exchanger 24 Capillary (capillary tube)
24a1 Connection portion with end of path of predetermined capillary 24a2 Portion of predetermined capillary at highest position 25 First shunt (divider)
41 Indoor expansion valve (first decompressor)
42 Indoor heat exchanger (use side heat exchanger)

JP-A-10-267469

Claims (8)

A main refrigerant circuit (10) having a compressor (21), a heat source side first heat exchanger (23) functioning as a radiator, a first decompressor (41), and a utilization side heat exchanger (42) functioning as an evaporator. )When,
A refrigerant having a heat source side second heat exchanger (13) and a second pressure reducer (15) for depressurizing the refrigerant cooled by the heat source side second heat exchanger, the pressure being reduced by the second pressure reducer A refrigerant flow path for supercooling (12) for cooling the refrigerant flowing from the heat source side first heat exchanger to the use side heat exchanger by:
With
In the heat source side first heat exchanger (23), a plurality of paths (23a, 23b, 23c,...) That are a plurality of refrigerant flow paths having different heights are formed.
The main refrigerant circuit (10) includes a flow divider (25) disposed between the heat source side first heat exchanger and the first pressure reducer, an end of the plurality of paths, and the flow divider. A plurality of capillaries (24),
The heat source side first heat exchanger (23) is disposed above the heat source side second heat exchanger (13).
Refrigeration equipment (1). The end (23a1) at the lowest position among the ends of the plurality of paths (23a, 23b, 23c,...) Of the heat source side first heat exchanger (23) and the flow divider (25) In the narrow tube (24a) connecting the two, the head difference between the portion (24a2) at the highest position and the connection portion (24a1) between the end portion (23a1) of the path is 200 mm or less.
The refrigeration apparatus according to claim 1. The shunt (25) is disposed at a position lower than or equal to the end (23a1) at the lowest position among the ends of the plurality of paths (23a, 23b, 23c,...). ing,
The refrigeration apparatus according to claim 1. The main refrigerant circuit (10) further includes a switching mechanism (22) that switches between a cooling operation and a heating operation by changing the direction of the flowing refrigerant,
During the heating operation, from the pipe (10c1) of the main refrigerant circuit (10) on the refrigerant inflow side of the heat source side first heat exchanger (23) to the heat source side second heat exchanger (13). A heating refrigerant flow path (18) that stops the flow of the refrigerant from the heat source side second heat exchanger (13) to the pipe (10c1) of the main refrigerant circuit (10) during the cooling operation. ,
Further equipped with,
The refrigeration apparatus according to any one of claims 1 to 3. The total volume of the refrigerant flow path formed in the heat source side second heat exchanger (13) is 5 to 45 of the total volume of the refrigerant flow path formed in the heat source side first heat exchanger (23). %
The refrigeration apparatus according to any one of claims 1 to 4. The heat source side first heat exchanger (23) and the heat source side second heat exchanger (13) are both cross fin tube type heat exchangers and share fins.
The refrigeration apparatus according to any one of claims 1 to 5. The heat source side first heat exchanger (23) and the heat source side second heat exchanger (13) are both cross-fin tube type heat exchangers,
The fins of the heat source side first heat exchanger and the fins of the heat source side second heat exchanger are provided separately.
The refrigeration apparatus according to any one of claims 1 to 5. Each of the first pressure reducer (41) and the second pressure reducer (15) is an expansion valve capable of adjusting an opening degree.
A control unit (8) for adjusting the opening of the first decompressor and the second decompressor;
Further comprising
The control unit (8) controls the opening of the second pressure reducer (15) so that the flow rate of the refrigerant flowing through the heat source side second heat exchanger (13) acting as a radiator is zero or small. Mode, having,
The refrigeration apparatus according to any one of claims 1 to 7.

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