Heat source unit and refrigeration device

Abstract

Provided is a heat source unit (2) for a refrigeration device (1) that comprises a first circuit (10) that includes a first heat exchanger (13) and circulates a first refrigerant that has a critical temperature of less than 45°C and a second circuit (20) that includes a second heat exchanger and circulates a second refrigerant that has a critical temperature of at least 45°C. The heat source unit (2) comprises the first heat exchanger (13) and the second heat exchanger (22). The first heat exchanger (13) has a plurality of heat transfer tubes that are arranged up and down. The second heat exchanger (22) is on the leeward side of the first heat exchanger 13. The first heat exchanger (13) and the second heat exchanger (22) are stacked in a first direction (D). The first heat exchanger (13) includes a first region (R1) and a second region (R2). The first region (R1) is the uppermost heat transfer tube and above. The second region (R2) is below the uppermost heat transfer tube. The second heat exchanger (22) coincides with the second region (R2) as seen in the first direction.

Description

Heat source unit and refrigeration device

[0001] The present invention relates to a heat source unit and a refrigeration device.

[0002] The refrigeration cycle device of Patent Document 1 (WO 2022 / 211078) includes a first refrigerant circuit using a first refrigerant and a second refrigerant circuit using a second refrigerant. Patent Document 1 describes that a second outdoor heat exchanger 23 of the second refrigerant circuit is disposed upwind of a first outdoor heat exchanger 18 of the first refrigerant circuit in the air flow direction of an outdoor fan 9.

[0003] The above-mentioned Patent Document 1 does not mention the relationship between the vertical position of the first outdoor heat exchanger 18 and the vertical position of the second outdoor heat exchanger 23 .

[0004] A heat source unit according to a first aspect is a heat source unit for a refrigeration device including a first circuit and a second circuit. The first circuit circulates a first refrigerant having a critical temperature of less than 45°C and includes a first heat exchanger. The second circuit circulates a second refrigerant having a critical temperature of 45°C or more and includes a second heat exchanger. The heat source unit includes a first heat exchanger and a second heat exchanger. The first heat exchanger has a plurality of heat transfer tubes. The plurality of heat transfer tubes are arranged in a vertical direction. The second heat exchanger is arranged on the downwind side of the first heat exchanger. The first heat exchanger and the second heat exchanger are stacked in a first direction. The first heat exchanger includes a first region and a second region. The first region is the uppermost heat transfer tube and above it. The second region is below the uppermost heat transfer tube. The second heat exchanger overlaps with the second region when viewed in the first direction.

[0005] When a refrigeration system including a heat source unit according to the first aspect is operated in cooling mode, for example, the air is heated by the first refrigerant flowing through the heat transfer tubes of the first heat exchanger. At this time, the air reaches its highest temperature near the top of the first heat exchanger. However, in the heat source unit according to the first aspect, the second heat exchanger is disposed on the downwind side of the second region below the top heat transfer tube of the first heat exchanger when viewed in the first direction, which is the direction of overlap with the first heat exchanger. This allows the second refrigerant in the second heat exchanger to avoid heat exchange with the air that has reached its highest temperature. This prevents a decrease in the heat exchange efficiency between the second refrigerant and the air.

[0006] A heat source unit according to a second aspect is the heat source unit according to the first aspect, further comprising a first compressor, a second compressor, a casing, and a partition plate. The first compressor compresses a first refrigerant. The second compressor compresses a second refrigerant. The casing houses the first heat exchanger, the second heat exchanger, the first compressor, and the second compressor. The partition plate divides the interior of the casing into a first chamber and a second chamber. The first heat exchanger and the second heat exchanger are disposed in the first chamber. The first compressor and the second compressor are disposed in the second chamber. The second heat exchanger is disposed on the second chamber side within the first chamber.

[0007] In the heat source unit of the second aspect, the second heat exchanger is disposed on the second chamber side, and therefore can be easily connected to the components disposed in the second chamber.

[0008] A heat source unit according to a third aspect is the heat source unit according to the first or second aspect, further comprising a fan, a first support member, and a second support member. The fan sends air to the second heat exchanger. The first support member supports the fan. The second support member supports the second heat exchanger.

[0009] In the heat source unit of the third aspect, even if the vertical length of the fan and the vertical length of the second heat exchanger are different, the fan is supported by the first support member and the second heat exchanger is supported by the second support member, so the fan and the second heat exchanger can be easily attached to the first and second support members.

[0010] A heat source unit according to a fourth aspect is the heat source unit according to the third aspect, wherein the second support member is connected to a structural member.

[0011] In the heat source unit of the fourth aspect, the second heat exchanger can be supported using a second support member connected to the structural member.

[0012] A heat source unit according to a fifth aspect is the heat source unit according to the first or second aspect, further comprising a fan, a motor, and a first support member. The fan sends air to the second heat exchanger. The motor drives the fan. The first support member supports the motor. The first support member further supports the second heat exchanger.

[0013] In the heat source unit of the fifth aspect, the second heat exchanger can be supported using the first support member that supports the motor that drives the fan.

[0014] A heat source unit according to a sixth aspect is the heat source unit according to any one of the first to fifth aspects, wherein the first heat exchanger further has a first fin, and the second heat exchanger has a second fin, and the first fin and the second fin are arranged at a distance from each other.

[0015] In the heat source unit of the sixth aspect, the first fins of the first heat exchanger and the second fins of the second heat exchanger are not common, so heat exchange between the first fins and the second fins can be suppressed, thereby further suppressing a decrease in heat exchange efficiency in the first heat exchanger and the second heat exchanger.

[0016] A heat source unit according to a seventh aspect is the heat source unit according to any one of the first to fifth aspects, wherein the first heat exchanger further has a first fin, the second heat exchanger has a second fin, and the first fin and the second fin are integral with each other.

[0017] In the heat source unit of the seventh aspect, the first fins of the first heat exchanger and the second fins of the second heat exchanger are common, and therefore the heat source unit can be easily manufactured.

[0018] A heat source unit according to an eighth aspect is the heat source unit according to any one of the first to seventh aspects, further comprising a third heat exchanger. The third heat exchanger exchanges heat between the first refrigerant and the second refrigerant.

[0019] As in the heat source unit of the eighth aspect, a dual circuit may be configured in which the first circuit and the second circuit are connected by a third heat exchanger.

[0020] A heat source unit according to a ninth aspect is the heat source unit according to any one of the first to eighth aspects, wherein the second heat exchanger has a different length in the vertical direction from a different length in the horizontal direction.

[0021] In the heat source unit of the ninth aspect, when the vertical length of the second heat exchanger is smaller than the horizontal length, the second heat exchanger can be positioned so as to increase the area that does not overlap with the high-temperature portion of the first heat exchanger. When the vertical length of the second heat exchanger is larger than the horizontal length, this is effective when there are restrictions on the installation position of the second heat exchanger.

[0022] A heat source unit according to a tenth aspect is the heat source unit according to any one of the first to ninth aspects, wherein the first circuit further includes a first compressor. The first compressor discharges a first refrigerant in a supercritical state.

[0023] As in the heat source unit of the tenth aspect, a refrigerant in a supercritical state may be used as the first refrigerant.

[0024] A heat source unit according to an eleventh aspect is the heat source unit according to the tenth aspect, wherein the first refrigerant includes carbon dioxide refrigerant.

[0025] In the heat source unit of the eleventh aspect, the first refrigerant can be used which contains carbon dioxide, which has a high heat dissipation temperature.

[0026] A heat source unit according to a twelfth aspect is the heat source unit according to any one of the first aspect to the eleventh aspect, wherein the second refrigerant is flammable.

[0027] As in the heat source unit of the twelfth aspect, a flammable refrigerant may be used as the second refrigerant.

[0028] A heat source unit according to a thirteenth aspect is the heat source unit according to the twelfth aspect, wherein the second refrigerant includes a hydrocarbon-based refrigerant.

[0029] In the heat source unit of the thirteenth aspect, the second refrigerant can be a hydrocarbon refrigerant having a low condensation temperature.

[0030] A refrigeration apparatus according to a fourteenth aspect includes a heat source unit and a utilization unit. The heat source unit is any one of the heat source units according to the first aspect to the thirteenth aspect. The utilization unit is connected to the heat source unit.

[0031] In the refrigeration apparatus of the fourteenth aspect, since the refrigeration apparatus is provided with the heat source unit, it is possible to suppress a decrease in heat exchange efficiency.

[0032] 1 is a schematic configuration diagram of a refrigeration device according to an embodiment of the present disclosure. FIG. 1 is a cross-sectional schematic diagram of a heat source unit. FIG. 1 is a cross-sectional schematic diagram of a heat source unit. FIG. 2 is a schematic diagram of a first heat exchanger. FIG. 3 is a perspective view of the first heat exchanger and the second heat exchanger. FIG. 4 is a schematic diagram of the first heat exchanger and the second heat exchanger as viewed in a first direction. FIG. 5 is a diagram illustrating the operation of the refrigeration device in cooling operation. FIG. 6 is a diagram illustrating the operation of the refrigeration device in heating operation. FIG. 7 is a perspective view of the first heat exchanger and the second heat exchanger of Modification 1 as viewed in a first direction. FIG. 8 is a schematic diagram of the first heat exchanger and the second heat exchanger of Modification 2 as viewed in a first direction. FIG. 9 is a schematic diagram of the first heat exchanger and the second heat exchanger of Modification 3 as viewed in a first direction. FIG. 10 is a cross-sectional schematic diagram of a heat source unit of Modification 4. FIG. 11 is a cross-sectional schematic diagram of a heat source unit of Modification 5. FIG. 12 is a schematic diagram of the first heat exchanger of Modification 8. FIG. 13 is a perspective view of the first heat exchanger of Modification 9. FIG. 14 is a schematic diagram of the first heat exchanger of Modification 9. FIG. 22 is a cross-sectional schematic diagram of a heat source unit according to a tenth modified example.

[0033] (1) Overall Configuration As shown in FIG. 1 , a refrigeration device 1 according to an embodiment of the present disclosure is a device used for heating and cooling the interior of a building or the like by performing a vapor compression refrigeration cycle operation.

[0034] The refrigeration device 1 includes a first circuit 10, a second circuit 20, and a control unit 6. The refrigeration device 1 of this embodiment has a binary circuit consisting of the vapor compression first circuit 10 and the vapor compression second circuit 20, and performs a binary refrigeration cycle.

[0035] A first refrigerant circulates through the first circuit 10. A second refrigerant circulates through the second circuit 20. The critical temperature of the second refrigerant is lower than the critical temperature of the first refrigerant. The first circuit 10 and the second circuit 20 are thermally connected via a third heat exchanger 30.

[0036] The refrigeration system 1 includes a heat source unit 2, a utilization unit 3, and communication pipes 4 and 5. The refrigeration system 1 is configured such that the heat source unit 2 and the utilization unit 3 are connected to each other via the communication pipes 4 and 5.

[0037] The heat source unit 2 includes a first heat exchanger 13 of the first circuit 10 and a second heat exchanger 22 of the second circuit 20. The second heat exchanger 22 is disposed on the downwind side of the first heat exchanger 13. When viewed in the stacking direction with the first heat exchanger 13, the second heat exchanger 22 overlaps with a second region R2 (see FIG. 4 ) that is below the uppermost heat transfer tube of the first heat exchanger 13.

[0038] (2) Detailed Configuration (2-1) First Circuit The first refrigerant flowing through the first circuit 10 has a critical temperature of less than 45°C, preferably 40°C or less. Here, the first refrigerant is non-flammable, non-toxic, or has a GWP of 500 or less. The first refrigerant is, for example, a natural refrigerant, and preferably contains carbon dioxide. The first refrigerant in this embodiment is a single refrigerant of carbon dioxide.

[0039] The first circuit 10 is a main circuit configured to heat or cool indoor air with a first refrigerant.

[0040] The first circuit 10 includes a first compressor 11 , a switching mechanism 12 , a first heat exchanger 13 , a third heat exchanger 30 , a first expansion mechanism 14 , a fourth heat exchanger 15 , and a first accumulator 16 .

[0041] The first compressor 11 is a device for compressing the first refrigerant, and is, for example, a positive displacement compressor such as a scroll type whose operating capacity can be varied by inverter control of the compressor motor. In this embodiment, the first compressor 11 discharges the first refrigerant in a supercritical state.

[0042] The switching mechanism 12 is a device that switches between a first state (see the solid line of the switching mechanism 12 in FIG. 1 ) in which the first heat exchanger 13 functions as a radiator for the first refrigerant and the fourth heat exchanger 15 functions as an evaporator for the first refrigerant, and a second state (see the dashed line of the switching mechanism 12 in FIG. 1 ) in which the first heat exchanger 13 functions as an evaporator for the first refrigerant and the fourth heat exchanger 15 functions as a radiator for the first refrigerant. The switching mechanism 12 is, for example, a four-way switching valve. In the first state, the switching mechanism 12 connects the discharge side of the first compressor 11 to the gas side of the first heat exchanger 13 and connects the suction side of the first compressor 11 to the gas side of the fourth heat exchanger 15. In addition, in the second state, the switching mechanism 12 connects the discharge side of the first compressor 11 to the gas side of the fourth heat exchanger 15, and also connects the suction side of the first compressor 11 to the gas side of the first heat exchanger 13.

[0043] The first heat exchanger 13 is a device for exchanging heat between the first refrigerant and the outdoor air without mixing them. In the first heat exchanger 13, the first refrigerant acquires cold or hot heat from the outdoor air. The first heat exchanger 13 is, for example, a fin-and-tube heat exchanger.

[0044] The first expansion mechanism 14 is a device that decompresses the first refrigerant, and is, for example, an electric expansion valve.

[0045] The fourth heat exchanger 15 is a device for exchanging heat between the first refrigerant and the indoor air, and is, for example, a fin-and-tube heat exchanger.

[0046] The first accumulator 16 is provided in the middle of the suction flow path that connects the switching mechanism 12 and the suction side of the first compressor 11. The first accumulator 16 separates the refrigerant that has flowed in into liquid refrigerant and gas refrigerant, and allows the gas refrigerant to flow to the suction side of the first compressor 11.

[0047] The third heat exchanger 30 is a device for exchanging heat between the first refrigerant and the second refrigerant without mixing them. The third heat exchanger 30 is a cascade heat exchanger, such as a plate-type heat exchanger. The third heat exchanger 30 has a first flow path 31 belonging to the first circuit 10 and a second flow path 32 belonging to the second circuit 20. In other words, the first flow path 31 constitutes a part of the first circuit 10, and the second flow path 32 constitutes a part of the second circuit 20. In further words, the first flow path 31 of the third heat exchanger 30 is included in the configuration of the first circuit 10, and the second flow path 32 of the third heat exchanger 30 is included in the configuration of the second circuit 20.

[0048] One end of the first flow path 31 is connected to the first heat exchanger 13 , and the other end is connected to the fourth heat exchanger 15 .

[0049] When the first heat exchanger 13 of the first circuit 10 is used as a radiator and the second heat exchanger 22 described later is used as a radiator, the third heat exchanger 30 is intended to supercool the first refrigerant cooled by the first heat exchanger 13, and plays a role of assisting the first circuit 10.

[0050] (2-2) Second Circuit The second refrigerant flowing through the second circuit 20 has a critical temperature of 45°C or higher, preferably 50°C or higher. Here, the second refrigerant is flammable. The second refrigerant is, for example, a hydrocarbon refrigerant such as R1234yf, R1234ze, or R32, and in this embodiment, a single refrigerant is R290.

[0051] The second circuit 20 constitutes a subcooling circuit during cooling operation, and is an assist circuit that assists the capacity of the first circuit 10 during cooling operation.

[0052] The second circuit 20 includes a second compressor 21 , a second heat exchanger 22 , a second expansion mechanism 23 , a second accumulator 24 , and a third heat exchanger 30 .

[0053] The second compressor 21 is a device for compressing the second refrigerant, and is, for example, a positive displacement compressor such as a scroll type whose operating capacity can be varied by inverter controlling the compressor motor.

[0054] The second heat exchanger 22 is a device for exchanging heat between the second refrigerant and the outdoor air without mixing them. In the second heat exchanger 22, the second refrigerant acquires cold or hot heat from the outdoor air. The second heat exchanger 22 is, for example, a microchannel heat exchanger or a fin-and-tube heat exchanger.

[0055] The second circuit 20 has a second flow path 32 of the third heat exchanger 30. The gas side of the second flow path 32 is connected to the second compressor 21, and the liquid side of the second flow path 32 is connected to the second expansion mechanism 23.

[0056] The second expansion mechanism 23 is a device that decompresses the second refrigerant, and is, for example, an electric expansion valve.

[0057] The second accumulator 24 is provided in the middle of the suction flow path that connects the third heat exchanger 30 and the suction side of the second compressor 21. The second accumulator 24 separates the refrigerant that has flowed into it into liquid refrigerant and gas refrigerant, and allows the gas refrigerant to flow to the suction side of the second compressor 21.

[0058] (2-3) Heat Source Unit In the following description, expressions indicating directions such as "up," "down," "front," "rear," "left," and "right" are used as appropriate, but these indicate the directions when the heat source unit 2 is installed outdoors and in normal use, and do not limit the contents of this disclosure unless otherwise specified. In this embodiment, the up-down direction is the vertical direction, and the left-right direction is the horizontal direction.

[0059] The heat source unit 2 is placed in a space different from the space in which the utilization units 3 are placed. Here, the heat source unit 2 is installed outdoors (on the roof of a building, near the exterior wall surface of a building, etc.).

[0060] As shown in Figures 2 and 3, the heat source unit 2 here is a side-blowing type that takes in outdoor air through an opening (intake port O1) on the back of the casing 41 and an opening (intake port O2) on the left side, and blows out the outdoor air that has been heat exchanged in the first heat exchanger 13 and the outdoor air that has been heat exchanged in the second heat exchanger 22 from an opening (outlet port O3) on the front of the casing 41.

[0061] The heat source unit 2 has a part of the first circuit 10 described above, the second circuit 20, a casing 41, a partition plate 42, a fan 43, a motor 44, a first support member 45, and a second support member 46. Specifically, the heat source unit 2 has the first compressor 11, the switching mechanism 12, the first heat exchanger 13, the first expansion mechanism 14, the first accumulator 16, the second compressor 21, the second heat exchanger 22, the second expansion mechanism 23, the third heat exchanger 30, the fan 43, the motor 44, and the casing 41, the partition plate 42, the first support member 45, and the second support member 46 shown in FIG.

[0062] The casing 41 houses the first compressor 11, the switching mechanism 12, the first heat exchanger 13, the first expansion mechanism 14, the first accumulator 16, the second compressor 21, the second heat exchanger 22, the second expansion mechanism 23, the second accumulator 24, the third heat exchanger 30, a partition plate 42, a fan 43, a motor 44, a first support member 45, and a second support member 46.

[0063] The casing 41 is a structural member that serves as a framework for constructing the heat source unit 2. The casing 41 shown in Figures 2 and 3 has a substantially rectangular parallelepiped shape. Specifically, the casing 41 includes a front plate 411, a top plate 412, a bottom plate 413, side plates 414, and a rear plate 415.

[0064] The front plate 411 is a plate-like member that forms the front surface of the casing 41. An air outlet O3 is formed in the front plate 411. The air outlet O3 is an opening for blowing outside air that has been taken into the casing 41 from the outside to the outside of the casing 41.

[0065] The top plate 412 is a plate-like member that forms the upper surface of the casing 41. The bottom plate 413 is a plate-like member that forms the lower surface of the casing 41. The top plate 412 and the bottom plate 413 face each other.

[0066] The side plate 414 is a plate-like member that forms the side surface of the casing 41. An intake port O2 is formed in the side plate 414. In FIG. 2 , the intake port O2 is formed on the left surface. A lower portion of the side plate 414 is fixed to the bottom plate 413.

[0067] The rear plate 415 is a plate-like member that forms the rear surface of the casing 41. An intake port O1 is formed in the rear plate 415. A lower portion of the rear plate 415 is fixed to the bottom plate 413.

[0068] The partition plate 42 is a plate-like member that extends in the vertical direction. The lower portion of the partition plate 42 is fixed to the bottom plate 413 of the casing 41.

[0069] The partition plate 42 divides the inside of the casing 41 into a first chamber S1 and a second chamber S2. Each of the first chamber S1 and the second chamber S2 is a space defined by the partition plate 42 and a front plate 411, a top plate 412, a bottom plate 413, a side plate 414, and a rear plate 415 of the casing 41.

[0070] Here, the first chamber S1 is an air supply chamber and an air guide passage through which air drawn in from the air inlets O1 and O2 flows to the air outlet O3. In this embodiment, the first chamber S1 is equipped with the first heat exchanger 13, the second heat exchanger 22, the fan 43, the motor 44, the first support member 45, the second support member 46, and the like.

[0071] The second chamber S2 is a machinery chamber and contains the first compressor 11, the second compressor 21, the switching mechanism 12, the first expansion mechanism 14, the second expansion mechanism 23, the first accumulator 16, the second accumulator 24, the third heat exchanger 30, and the like.

[0072] Here, the first heat exchanger 13, the second heat exchanger 22, the fan 43, the motor 44, the first support member 45, and the second support member 46, which are arranged in the first chamber S1, will be mainly described.

[0073] 2, the first heat exchanger 13 is formed in an L-shape when viewed from above. In detail, the first heat exchanger 13 includes a portion extending along the back surface of the casing 41 from near the partition plate 42 to near the left rear corner of the casing 41, a portion curved near the left rear corner of the casing 41, and a portion extending along the side plate 414 from near the left rear corner of the casing 41 to near the left front corner.

[0074] As shown in FIG. 4 , the first heat exchanger 13 includes a first heat transfer tube 131 , a plurality of first fins 132 , and a pair of tube plates 141 and 142 .

[0075] The first heat transfer pipes 131 are arranged in the vertical direction. Specifically, the first heat transfer pipes 131 include a plurality of straight pipe sections 131x formed in a linear shape and a plurality of curved pipe sections 131y formed in a U-shape. The straight pipe sections 131x are arranged at intervals in the vertical direction and extend in a direction perpendicular to the vertical direction. The curved pipe sections 131y are arranged at the ends of the first heat exchanger 13 in the width direction (the left-right direction in FIG. 4 ) and connect two straight pipe sections 131x arranged in the vertical direction to each other. Here, the first heat transfer pipes 131 are circular pipes, and a flow path through which the first refrigerant flows is formed in the first heat transfer pipes 131.

[0076] The first fins 132 are joined to the first heat transfer tubes 131. Here, the first fins 132 are joined to the straight tube portions 131x of the first heat transfer tubes 131. The multiple first fins 132 are arranged in a direction perpendicular to the up-down direction and extend in the up-down direction.

[0077] The pair of tube sheets 141, 142 support the straight pipe section 131x of the first heat transfer tube 131. The tube sheet 141 is connected to one end of the straight pipe section 131x, and the tube sheet 142 is connected to the other end of the straight pipe section 131x. The tube sheets 141, 142 are arranged parallel to the first fin 132 and extend in the vertical direction.

[0078] 4, in the first heat exchanger 13, the first refrigerant discharged from the first compressor 11 flows into the uppermost first heat transfer tube 131a, passes through the straight tube portion 131x and the curved tube portion 131y in this order, and flows out of the lowermost first heat transfer tube 131. Therefore, the temperature of the first refrigerant increases from bottom to top.

[0079] 4 and 6 , the first heat exchanger 13 includes a first region R1 and a second region R2. The first region R1 includes the uppermost first heat transfer tube 131a and the area above it. In other words, the first region R1 includes the uppermost first heat transfer tube 131a and the first fins 132 above the uppermost first heat transfer tube 131a. The second region R2 is below the uppermost first heat transfer tube 131a. In other words, the second region includes the first heat transfer tubes 131 other than the uppermost first heat transfer tube 131a and the first fins 132 below the uppermost first heat transfer tube 131a.

[0080] In the present embodiment, the first region R1 includes the uppermost straight pipe section 131x, an upper portion of the uppermost curved pipe section 131y, an upper portion of the first fin 132, and an upper portion of the pair of tube sheets 141, 142. The second region R2 includes a plurality of straight pipe sections 131x other than the uppermost one, a plurality of curved pipe sections 131y below the upper portion of the uppermost curved pipe section 131y, an intermediate portion and a lower portion of the first fin 132, and an intermediate portion and a lower portion of the pair of tube sheets 141, 142.

[0081] As shown in FIG. 2 , the second heat exchanger 22 is I-shaped in top view. Specifically, the second heat exchanger 22 extends along the back surface of the casing 41 from near the partition plate 42 to the middle of the first chamber S1 in the left-right direction. Thus, the second heat exchanger 22 is disposed on the second chamber S2 side of the first chamber S1. The left-right center of the first chamber S1 and the left-right center of the second heat exchanger 22 are different. The left-right center of the first chamber S1 is the center between the side plate 414 (the left plate in FIG. 2 ) and the partition plate 42, which is located at the same position as the second heat exchanger 22 in the front-rear direction. In this embodiment, the left-right center of the second heat exchanger 22 is located closer to the second chamber S2 (to the right) than the left-right center of the first chamber S1. Therefore, the second heat exchanger 22 does not extend to the left side of the first chamber S1 in the left-right direction.

[0082] The second heat exchanger 22 has a generally rectangular parallelepiped shape. Specifically, the vertical length and the horizontal length of the second heat exchanger 22 are different. In Figures 5 and 6, the vertical length of the second heat exchanger 22 is greater than the horizontal length.

[0083] The second heat exchanger 22 includes a plurality of second heat transfer tubes and a plurality of second fins. The second fins are joined to the second heat transfer tubes.

[0084] In this embodiment, the first fins 132 of the first heat exchanger 13 and the second fins of the second heat exchanger 22 are spaced apart. In this embodiment, at least one of the first fins 132 and the second fins is spaced apart, and in this embodiment, all of the first fins 132 and the second fins are spaced apart. Therefore, the first fins 132 and the second fins are separate members.

[0085] As shown in FIG. 2 , the fan 43 is disposed in the center of the first chamber S1 in the left-right direction, on the front side of the first chamber S1. The fan 43 sends air to the first heat exchanger 13 and the second heat exchanger 22. In this embodiment, the fan 43 flows outdoor air through both the first heat exchanger 13 and the second heat exchanger 22. Here, the fan 43 generates an air flow in which the outdoor air is guided to the first heat exchanger 13 and the second heat exchanger 22, where it exchanges heat with the first refrigerant in the first heat exchanger 13 and the second refrigerant in the second heat exchanger 22, and then discharged to the outside. In this embodiment, the air flow direction F is the first direction D in which the first heat exchanger 13 and the second heat exchanger 22 are stacked. The fan 43 is driven by a motor 44.

[0086] 2, 3, and 5, the second heat exchanger 22 is disposed on the downwind side of the first heat exchanger 13. Specifically, the second heat exchanger 22 is disposed on the downwind side of the first heat exchanger 13 in the flow direction F of the air generated by the fan 43 (see FIG. 2). Here, the second heat exchanger 22 is disposed in front of the first heat exchanger 13.

[0087] The first heat exchanger 13 and the second heat exchanger 22 are stacked in a first direction D (see FIG. 2 ). The first direction D is a direction perpendicular to the surface where the first heat exchanger 13 and the second heat exchanger 22 face each other. In this embodiment, the first direction D is the front-to-rear direction.

[0088] As shown in FIG. 6 , the second heat exchanger 22 overlaps with the second region R2 of the first heat exchanger 13 when viewed in the first direction. In other words, the first region R1 of the first heat exchanger 13 is above the second heat exchanger 22 when viewed in the first direction. In yet other words, the second heat exchanger 22 does not overlap with the first region R1 of the first heat exchanger 13 when viewed in the first direction. In yet other words, the second heat exchanger 22 overlaps only with the second region R2 of the first heat exchanger 13 when viewed in the first direction. The first direction view is a view in the direction in which the first heat exchanger 13 and the second heat exchanger 22 overlap. In this embodiment, the second heat exchanger 22 overlaps with a portion of the second region R2 of the first heat exchanger 13 when viewed in the first direction. Here, the second heat exchanger 22 overlaps with the lower part of the second region R2 of the first heat exchanger 13 when viewed in the first direction.

[0089] As shown in FIGS. 5 and 6, in this embodiment, the entire second heat exchanger 22 is included in the second region R2 when viewed in the first direction.

[0090] In addition, in FIG. 2 , the fan 43 overlaps the first heat exchanger 13 and the second heat exchanger 22 when viewed in the first direction.

[0091] 2 and 3, the fan 43 is supported by a first support member 45. The second heat exchanger 22 is supported by a second support member 46. The first support member 45 and the second support member 46 are separate members.

[0092] The first support member 45 supports the motor 44, thereby supporting the fan 43. The first support member 45 includes a main body 45a that supports the motor from both left and right ends, and a motor base 45b. The main body 45a extends in the vertical direction. The upper end of the main body 45a is connected to the top plate 412 of the casing 41. The lower end of the main body 45a is connected to the motor base 45b. The motor base 45b is connected to the bottom plate 413 of the casing 41.

[0093] The second support member 46 supports the second heat exchanger 22 from both left and right ends. The second support member 46 extends in the up and down direction. The second support member 46 is connected to a structural member. Specifically, the upper end of the second support member 46 is connected to the top plate 412 of the casing 41. The lower end of the second support member 46 is connected to the bottom plate 413 of the casing 41.

[0094] (2-4) Utilization Unit The utilization unit 3 shown in Fig. 1 is installed indoors (inside a building). As described above, the utilization unit 3 is connected to the utilization unit 3 via the connecting pipes 4 and 5, and constitutes a part of the first circuit 10.

[0095] The utilization unit 3 has a fourth heat exchanger 15. Here, the utilization unit 3 is installed by being embedded in or suspended from the ceiling of a room in a building or the like, or by being hung on a wall surface of the room.

[0096] (2-5) Connecting Pipes The connecting pipes 4, 5 are refrigerant pipes that are installed on-site when the refrigeration device 1 is installed in an installation location such as a building. One end of the liquid-side connecting pipe 4 is connected to the liquid-side end of the heat source unit 2, and the other end of the connecting pipe 4 is connected to the liquid-side end of the fourth heat exchanger 15 of the utilization unit 3. One end of the gas-side connecting pipe 5 is connected to the gas-side end of the heat source unit 2, and the other end of the connecting pipe 5 is connected to the gas-side end of the fourth heat exchanger 15 of the utilization unit 3.

[0097] (2-6) Control Unit The components of the heat source unit 2 and the utilization units 3 are controlled by a control unit 6. The control unit 6 is configured by communication connections with electrical equipment units, etc. provided in the heat source unit 2 and control boards, etc. provided in the utilization units 3. The control unit 6 controls the components of the refrigeration device 1 (here, the heat source unit 2 and the utilization units 3). In other words, the control unit 6 controls the operation of the entire refrigeration device 1.

[0098] The control unit 6 is realized by a computer. The control unit 6 includes a control and arithmetic unit and a storage device. The control and arithmetic unit can be a processor such as a CPU or a GPU. The control and arithmetic unit reads a program stored in the storage device and performs predetermined image processing and arithmetic processing in accordance with the program. Furthermore, the control and arithmetic unit can write the results of calculations to the storage device and read information stored in the storage device in accordance with the program.

[0099] (3) Operation The operation of the refrigeration device 1 will be described with reference to Figures 1 to 8. The refrigeration device 1 is capable of performing cooling operation to cool indoor air and heating operation to heat indoor air for indoor air conditioning. In cooling operation and heating operation, the operation of the refrigeration device 1 is controlled by the control unit 6.

[0100] (3-1) Cooling Operation As shown in FIG. 7, during cooling operation, the switching mechanism 12 is switched to the first state (the state in which the switching mechanism 12 is in the solid line) so that the first heat exchanger 13 functions as a radiator of the first refrigerant and the fourth heat exchanger 15 functions as an evaporator of the first refrigerant.

[0101] In the first circuit 10, the first refrigerant in a supercritical state discharged from the first compressor 11 is sent to the first heat exchanger 13 via the switching mechanism 12. The first refrigerant sent to the first heat exchanger 13 is cooled by exchanging heat with outdoor air supplied by the fan 43, thereby releasing heat. The first refrigerant that has released heat in the first heat exchanger 13 is sent to the first flow path 31 of the third heat exchanger 30. The first refrigerant sent to the first flow path 31 is further cooled in the third heat exchanger 30 by exchanging heat with the second refrigerant flowing through the second flow path 32. The first refrigerant that has been further cooled in the third heat exchanger 30 is decompressed by the first expansion mechanism 14 and then flows out of the heat source unit 2.

[0102] The first refrigerant that flows out of the heat source unit 2 flows into the utilization unit 3 via the liquid side connection pipe 4. In the utilization unit 3, the first refrigerant is sent to the fourth heat exchanger 15. The first refrigerant sent to the fourth heat exchanger 15 is heated through heat exchange with the indoor air and evaporates. The first refrigerant that has evaporated in the fourth heat exchanger 15 flows out of the utilization unit 3.

[0103] The first refrigerant flowing out of the utilization units 3 passes through the gas-side communication pipe 5 and flows into the heat source unit 2. In the heat source unit 2, the first refrigerant passes through the switching mechanism 12 and the first accumulator 16 and is again sucked into the first compressor 11.

[0104] In the second circuit 20, the second refrigerant discharged from the first compressor 11 is sent to the second heat exchanger 22. The second refrigerant sent to the second heat exchanger 22 is cooled by heat exchange with outdoor air supplied by the fan 43, thereby releasing heat. This outdoor air is air that has passed through the second region R2 of the first heat exchanger 13. The second refrigerant that has released heat in the second heat exchanger 22 is decompressed by the second expansion mechanism 23 and then sent to the second flow path 32 of the third heat exchanger 30. The second refrigerant sent to the second flow path 32 is heated and evaporated in the third heat exchanger 30 by heat exchange with the first refrigerant flowing through the first flow path 31. The second refrigerant that has evaporated in the third heat exchanger 30 is drawn back into the second compressor 21 via the second accumulator 24.

[0105] Here, the flow of refrigerant in the first heat exchanger 13 during cooling operation will be described mainly with reference to FIG. 4 . As shown in FIG. 4 , when the first heat exchanger 13 functions as a radiator for the first refrigerant, the first refrigerant discharged from the first compressor 11 flows into the straight pipe section 131x of the uppermost first heat transfer pipe 131a. The first refrigerant flowing through the uppermost straight pipe section 131x radiates a portion of its heat by exchanging heat with outdoor air and reaches the uppermost curved pipe section 131y. The first refrigerant then turns around at the curved pipe section 131y and flows to the lower straight pipe section 131x. The first refrigerant flowing through the lower straight pipe section 131x again radiates more heat by exchanging heat with outdoor air and reaches the lower curved pipe section 131y. In this way, the first refrigerant flows downward, reaches the lowermost straight pipe section 131x, and flows out of the first heat exchanger 13.

[0106] (3-2) Heating Operation As shown in Fig. 8, during heating operation, the switching mechanism 12 is switched to the second state (the state in which the switching mechanism 12 is in the broken line) so that the first heat exchanger 13 functions as an evaporator of the first refrigerant and the fourth heat exchanger 15 functions as a radiator of the first refrigerant. Furthermore, during heating operation, the second compressor 21 is not started, and the second refrigerant is not circulated in the second circuit 20. Here, the second expansion mechanism 23 is fully closed.

[0107] In the first circuit 10 , the first refrigerant in a supercritical state discharged from the first compressor 11 flows out of the heat source unit 2 through the switching mechanism 12 .

[0108] The refrigerant flowing out of the heat source unit 2 flows into the utilization unit 3 via the gas-side connection pipe 5. In the utilization unit 3, the first refrigerant is sent to the fourth heat exchanger 15. The first refrigerant sent to the fourth heat exchanger 15 is cooled by exchanging heat with the indoor air, thereby releasing heat. The first refrigerant that has released heat in the fourth heat exchanger 15 flows out of the utilization unit 3.

[0109] The first refrigerant flowing out of the utilization units 3 flows into the heat source unit 2 via the liquid-side connection pipe 4. In the heat source unit 2, the first refrigerant is sent to the first heat exchanger 13 through the first expansion mechanism 14 and the first flow path 31 of the third heat exchanger 30. The first refrigerant sent to the first heat exchanger 13 is heated and evaporated by heat exchange with outdoor air supplied by the fan 43. The first refrigerant evaporated in the first heat exchanger 13 is sucked back into the first compressor 11 via the switching mechanism 12 and the first accumulator 16.

[0110] (4) Features (4-1) The heat source unit 2 according to this embodiment is a heat source unit 2 for a refrigeration system 1 including a first circuit 10 and a second circuit 20. The first circuit 10 circulates a first refrigerant having a critical temperature of less than 45°C and includes a first heat exchanger 13. The second circuit 20 circulates a second refrigerant having a critical temperature of 45°C or higher and includes a second heat exchanger 22. The heat source unit 2 includes the first heat exchanger 13 and the second heat exchanger 22. The first heat exchanger 13 has a plurality of first heat transfer tubes 131 (heat transfer tubes). The plurality of first heat transfer tubes 131 are arranged in the vertical direction. The second heat exchanger 22 is arranged on the downwind side of the first heat exchanger 13. The first heat exchanger 13 and the second heat exchanger 22 are stacked in a first direction D. The first heat exchanger 13 includes a first region R1 and a second region R2. The first region R1 is the uppermost first heat transfer tube 131a and the area above it. The second region R2 is below the uppermost first heat transfer tube 131a. The second heat exchanger 22 overlaps with the second region R2 when viewed in the first direction.

[0111] A first refrigerant with a critical temperature of less than 45°C has a high heat dissipation temperature. Therefore, when the first refrigerant is subjected to heat exchange with air, which serves as a heat source, in a radiator, if the air temperature is high, the first refrigerant does not undergo a phase change in the radiator, reducing the enthalpy difference resulting from the heat exchange, resulting in poor efficiency. Therefore, in this embodiment, the second circuit 20, through which a second refrigerant with a critical temperature of 45°C or higher circulates, is used to supercool the first refrigerant, thereby increasing the cooling capacity obtained.

[0112] When the refrigeration system 1 including the heat source unit 2 is operated in cooling mode, for example, the air is heated by the first refrigerant flowing through the first heat transfer tube 131 of the first heat exchanger 13. At this time, the air reaches its highest temperature near the top of the first heat exchanger 13. In particular, with a supercritical refrigerant, the air temperature is highest at the top (inlet) and gradually decreases downstream. However, in the heat source unit 2 of this embodiment, the second heat exchanger 22 is positioned on the downwind side of the second region R2, below the topmost first heat transfer tube 131a of the first heat exchanger 13, when viewed in the first direction, i.e., the direction of overlap with the first heat exchanger 13. Therefore, in the second heat exchanger 22, the second refrigerant can avoid heat exchange with the hottest air. This suppresses a decrease in the heat exchange efficiency between the second refrigerant and the air.

[0113] (4-2) The heat source unit 2 according to the present embodiment preferably further includes a first compressor 11, a second compressor 21, a casing 41, and a partition plate 42. The first compressor 11 compresses a first refrigerant. The second compressor 21 compresses a second refrigerant. The casing 41 houses the first heat exchanger 13 and the second heat exchanger 22. The partition plate 42 divides the interior of the casing 41 into a first chamber S1 and a second chamber S2. The first heat exchanger 13 and the second heat exchanger 22 are disposed in the first chamber S1. The first compressor 11 and the second compressor 21 are disposed in the second chamber S2. Within the first chamber S1, the second heat exchanger 22 is disposed on the second chamber S2 side.

[0114] Here, since the second heat exchanger 22 is disposed on the second chamber S2 side, it can be easily connected to the components disposed in the second chamber S2.

[0115] (4-3) The heat source unit 2 according to the present embodiment preferably further includes a fan 43, a first support member 45, and a second support member 46. The fan 43 sends air to the second heat exchanger 22. The first support member 45 supports the fan 43. The second support member 46 supports the second heat exchanger 22.

[0116] Here, even if the vertical length of the fan 43 is different from the vertical length of the second heat exchanger 22, the fan 43 is supported by the first support member 45 and the second heat exchanger 22 is supported by the second support member 46, so the fan 43 and the second heat exchanger 22 can be easily attached to the first support member 45 and the second support member 46.

[0117] (4-4) In the heat source unit 2 according to the present embodiment, the second support member 46 is preferably connected to a structural member. Here, the second heat exchanger 22 can be supported using the second support member 46 connected to the structural member.

[0118] (4-5) In the heat source unit 2 according to the present embodiment, preferably, the first heat exchanger 13 further has a first fin 132. The second heat exchanger 22 has a second fin. The first fin 132 and the second fin are arranged apart from each other.

[0119] Here, the first fins 132 of the first heat exchanger 13 and the second fins of the second heat exchanger 22 are not common, so heat exchange between the first fins 132 and the second fins can be suppressed. Therefore, a decrease in the heat exchange efficiency in the first heat exchanger 13 and the second heat exchanger 22 can be further suppressed.

[0120] (4-6) The heat source unit 2 according to this embodiment preferably further includes a third heat exchanger 30. The third heat exchanger 30 exchanges heat between the first refrigerant and the second refrigerant.

[0121] In this way, a binary circuit may be configured in which the first circuit 10 and the second circuit 20 are connected by the third heat exchanger 30.

[0122] (4-7) In the heat source unit 2 according to this embodiment, the second heat exchanger 22 preferably has a vertical length different from a horizontal length.

[0123] Here, when the vertical length of the second heat exchanger 22 is smaller than the horizontal length, the second heat exchanger 22 can be arranged to increase the area that does not overlap with the high-temperature portion of the first heat exchanger 13. When the vertical length of the second heat exchanger 22 is larger than the horizontal length, this is effective when there are restrictions on the installation position of the second heat exchanger 22.

[0124] (4-8) In the heat source unit 2 according to the present embodiment, the first circuit 10 preferably further includes a first compressor 11. The first compressor 11 discharges a first refrigerant in a supercritical state. In this manner, a refrigerant in a supercritical state may be used as the first refrigerant.

[0125] (4-9) In the heat source unit according to this embodiment, the first refrigerant preferably contains carbon dioxide refrigerant. Here, a first refrigerant containing carbon dioxide, which has a high heat dissipation temperature, can be used.

[0126] (4-10) In the heat source unit 2 according to this embodiment, the second refrigerant is preferably flammable. In this manner, a flammable refrigerant may be used as the second refrigerant.

[0127] (4-11) In the heat source unit 2 according to this embodiment, the second refrigerant preferably contains a hydrocarbon-based refrigerant. Here, a second refrigerant containing a hydrocarbon-based refrigerant with a low condensation temperature can be used.

[0128] (4-12) The refrigeration device 1 according to this embodiment includes a heat source unit 2 and a utilization unit 3. The heat source unit 2 is any one of the heat source units described above. The utilization unit 3 is connected to the heat source unit 2.

[0129] Here, since the heat source unit 2 is provided, it is possible to suppress a decrease in heat exchange efficiency.

[0130] (5) Modifications (5-1) Modification 1 In the above embodiment, the second heat exchanger 22 does not extend to the left side of the first chamber S1 in the left-right direction to its full extent, but this is not limited to this. In this modification, as shown in Figures 9 and 10, the left-right width of the second heat exchanger 22 has its maximum length.

[0131] Specifically, the second heat exchanger 22 extends to face a portion of the first heat exchanger 13 that extends from the partition plate 42 to near the left rear corner of the casing 41. The second heat exchanger 22 extends in the left-right direction to an extent that it does not come into contact with the first heat exchanger 13.

[0132] (5-2) Modification 2 In the above embodiment, the entire second heat exchanger 22 is encompassed within the second region R2, but the second heat exchanger 22 is not particularly limited as long as it overlaps with at least a portion of the second region R2 when viewed in the first direction.

[0133] In this modification, as shown in FIG. 11 , a part of the second heat exchanger 22 overlaps with the second region R2 , and the remaining part does not overlap with the first heat exchanger 13 .

[0134] (5-3) Modification 3 In the above embodiment, the lower end of the second heat exchanger 22 and the lower end of the first heat exchanger are aligned in the up-down direction, but this is not limiting as long as they do not overlap with the first region R1.

[0135] The lower end of the first heat exchanger 13 may be located higher than the lower end of the second heat exchanger 22, but in this modified example, as shown in Figure 12, the lower end of the first heat exchanger 13 is located lower than the lower end of the second heat exchanger 22.

[0136] (5-4) Modification 4 In the above embodiment, the second support member 46 supports both the left and right ends of the second heat exchanger 22, but the present invention is not limited to this.

[0137] In this modified example, as shown in Figure 13, the lower end of the second support member 46 is connected to the upper end of the second heat exchanger 22, and the upper end of the second support member 46 is connected to the top plate 412 of the casing 41.

[0138] (5-5) Modification 5 (5-5-1) Overview In the above embodiment, the first support member 45 and the second support member 46 are separate members, but this is not limited to this. In this modification, as shown in Fig. 14, the first support member 45 that supports the fan 43 supports the second heat exchanger 22. In other words, the support member that supports the fan 43 and the support member that supports the second heat exchanger 22 are the same.

[0139] In this modification, the motor base 45b of the first support member supports the lower end of the second heat exchanger 22. Furthermore, a second support member 46 that is connected to the main body 45a of the first support member 45 and extends in the front-rear direction supports the upper end of the second heat exchanger 22.

[0140] (5-5-2) Features The heat source unit 2 according to this modification further includes a fan 43, a motor 44, and a first support member 45. The fan 43 sends air to the second heat exchanger 22. The motor 44 drives the fan 43. The first support member 45 supports the motor 44. The first support member 45 further supports the second heat exchanger 22.

[0141] Here, the second heat exchanger 22 can be supported by using the first support member 45 that supports the motor 44 that drives the fan 43 .

[0142] (5-6) Modification 6 (5-6-1) Overview In the above embodiment, the first fins 132 of the first heat exchanger 13 and the second fins of the second heat exchanger 22 are separate members, but this is not limiting. In this modification, the first fins and the second fins are integral with each other.

[0143] Specifically, a portion of the first fin and at least a portion of the second fin are connected to each other. As long as the first fin and the second fin are connected to each other, holes such as perforations may be formed in the first fin and the second fin.

[0144] (5-6-2) Features In the heat source unit according to this modification, the first heat exchanger 13 further has first fins. The second heat exchanger 22 has second fins. The first fins and the second fins are integral with each other.

[0145] The term "integral" means that at least a portion of the first fin and the second fin are connected, and includes the case where a hole is formed in a portion of the fin, such as a perforation.

[0146] Here, the first fins of the first heat exchanger 13 and the second fins of the second heat exchanger 22 are common, so that the first heat exchanger 13 and the second heat exchanger 22 can be manufactured easily.

[0147] (5-7) Modification 7 In the above embodiment, the common fan 43 sends air to the first heat exchanger 13 and the second heat exchanger 22, but this is not limiting. In this modification, a fan that sends air to the first heat exchanger 13 and a fan that sends air to the second heat exchanger 22 are provided separately.

[0148] (5-8) Modification 8 In the above embodiment, when the first heat exchanger 13 functions as a radiator for the first refrigerant, the first heat exchanger 13 whose temperature increases from bottom to top has been described as an example. However, this is not limiting. In this modification, a plurality of first heat exchangers 13 whose temperature increases from bottom to top, as in the above embodiment, are stacked vertically.

[0149] Specifically, as shown in FIG. 15 , the first heat exchanger 13 a of this modified example includes a plurality of the first heat exchangers 13 of the above embodiments, an anti-freeze path 135, a diverter 136, and a collecting pipe 137.

[0150] A freeze prevention path 135 is disposed below the vertically stacked first heat exchangers 13. In other words, the freeze prevention path 135 is provided in the lowest stage of the first heat exchanger 13a. The freeze prevention path 135 serves as a freeze prevention pipe when the first heat exchanger 13b functions as an evaporator for the first refrigerant.

[0151] When the first heat exchanger 13a functions as a radiator for the first refrigerant, the collecting pipe 137 distributes the first refrigerant flowing into the first heat exchanger 13a and causes the first refrigerant to flow to the upper parts of each of the multiple first heat exchangers 13. As in the above embodiment, the first refrigerant flows from the top to the bottom in each first heat exchanger 13. The first refrigerant flowing out from the lower parts of each first heat exchanger 13 is collected in the flow divider 136 and flows out of the first heat exchanger 13a.

[0152] As in the above embodiment, the first heat exchanger 13a includes a first region R1 below the uppermost first heat transfer tube 131a and the uppermost first heat transfer tube 131a of the first heat exchanger 13a, and a second region R2 below the uppermost first heat transfer tube 131a. The uppermost first heat transfer tube 131a, which forms the boundary of the first region R1, is the first heat transfer tube located in the uppermost first heat exchanger 13 among the multiple first heat exchangers 13. In the first heat exchanger 13a of this modification, the air temperature is highest near the uppermost heat exchanger of each first heat exchanger 13. The second heat exchanger 22 is disposed on the downwind side of the second region R2 below the uppermost first heat transfer tube 131a of the first heat exchanger 13a when viewed in the first direction, which is the direction of overlap with the first heat exchanger 13. Therefore, the second refrigerant flowing through the second heat exchanger 22 can avoid heat exchange with the air that has reached the highest temperature at least near the top stage, thereby suppressing a decrease in the efficiency of heat exchange between the second refrigerant and the air.

[0153] In the first heat exchanger 13a, the inlets of the first heat exchangers 13 may be gathered at the top. In this case, the temperature near the inlet of the first refrigerant becomes the highest, so it is preferable that the second heat exchanger 22 is arranged so as not to overlap with the inlet of the first refrigerant.

[0154] (5-9) Modification 9 In the above embodiment, the first heat exchanger 13 is a fin-and-tube heat exchanger, but this is not limiting. The first heat exchanger may be any heat exchanger, such as a microchannel heat exchanger. As shown in FIG. 16 , the first heat exchanger 13b in this modification is a microchannel heat exchanger.

[0155] The first heat exchanger 13b has a plurality of first heat transfer tubes 131, a plurality of first fins 132, a first header 133 shown in FIG. 17, and a second header 134.

[0156] The plurality of first heat transfer pipes 131 are arranged in the vertical direction. Specifically, the plurality of first heat transfer pipes 131 are arranged at intervals in the vertical direction and extend in a direction perpendicular to the vertical direction. Here, the first heat transfer pipes 131 have a flat shape, and each first heat transfer pipe 131 has a plurality of flow paths through which the first refrigerant flows.

[0157] The first fins 132 are joined to the first heat transfer pipes 131. The first fins 132 are arranged in a direction perpendicular to the up-down direction and extend in the up-down direction.

[0158] 17, a first header 133 is connected to one end of the first heat transfer tube 131, and a second header 134 is connected to the other end of the first heat transfer tube 131. The first header 133 and the second header 134 extend in the vertical direction.

[0159] The first header 133 is an inlet / outlet header having an inlet and an outlet for the first refrigerant. The first header 133 is divided into an upper region 133a, a middle region 133b, and a lower region 133c. The upper region 133a, the middle region 133b, and the lower region 133c are aligned vertically. When the first heat exchanger 13b functions as a radiator for the first refrigerant, the inlet for the first refrigerant is connected to the upper region 133a of the first header 133, and the outlet for the first refrigerant is connected to the lower region 133c of the first header 133.

[0160] The second header 134 is a folded header. The second header 134 is divided into an upper region 134a and a lower region 134b. The upper region 134a and the lower region 134b are aligned in the vertical direction.

[0161] The first heat exchanger 13b has a first flow path group X, a second flow path group Y, a third flow path group Z, and a fourth flow path W, which are arranged in the vertical direction. In the first heat exchanger 13b, each of the first heat transfer tubes arranged in the vertical direction belongs to one of the multiple flow path groups X, Y, Z, or the fourth flow path W. The first flow path group X is the uppermost flow path group and includes multiple first heat transfer tubes 131. The first flow path group X includes the uppermost first heat transfer tube 131a. One end of the first heat transfer tube 131 belonging to the first flow path group X is connected to an upper region 133a of the first header 133, and the other end is connected to an upper region 134a of the second header 134.

[0162] The second flow path group Y is a flow path group located below the first flow path group X, and includes a plurality of first heat transfer tubes 131. One end of the first heat transfer tubes 131 belonging to the second flow path group Y is connected to the middle region 133b of the first header 133, and the other end is connected to the upper region 134a of the second header.

[0163] The third flow path group Z is a flow path group located below the second flow path group Y, and includes a plurality of first heat transfer tubes 131. One end of the first heat transfer tubes 131 belonging to the third flow path group Z is connected to the middle region 133b of the first header 133, and the other end is connected to the lower region 134b of the second header.

[0164] The fourth flow path W is the lowest flow path and includes one or more first heat transfer pipes 131. The first heat transfer pipes 131 belonging to the fourth flow path W serve as anti-freeze pipes when the first heat exchanger 13b functions as an evaporator for the first refrigerant. One end of the first heat transfer pipe 131 belonging to the fourth flow path W is connected to the lower region 133c of the first header 133, and the other end is connected to the lower region 134b of the second header 134.

[0165] 17 , the first refrigerant discharged from the first compressor 11 flows in the following order: upper region 133a of the first header 133, first flow path group X, upper region 134a of the second header 134, second flow path group Y, intermediate region 133b of the first header 133, third flow path group Z, lower region 134b of the second header 134, fourth flow path W, and lower region 133c of the first header 133. Therefore, the first refrigerant has higher temperatures in the order of first flow path group X, second flow path group Y, third flow path group Z, and fourth flow path W.

[0166] Similar to the above embodiment, the first heat exchanger 13b includes a first region R1 and a second region R2. In this modification, the first region R1 includes an upper portion of the first flow path group X, an upper portion of the upper region 133a of the first header 133, and an upper portion of the upper region 134a of the second header 134. The second region R2 includes a lower portion of the first flow path group X, the second flow path group Y, the third flow path group Z, the fourth flow path W, a lower portion of the upper region 133a of the first header 133, the middle region 133b, the lower region 133c, a lower portion of the upper region 134a of the second header 134, and the lower region 134b.

[0167] As described above, when the first heat exchanger 13 functions as a radiator for the first refrigerant, the refrigerant flowing through the first flow path group X in the first heat exchanger 13 is hotter than the refrigerant flowing through the second flow path group Y, the third flow path group Z, and the fourth flow path W. Therefore, the air that exchanges heat with the first refrigerant flowing through the first flow path group X becomes hotter. Therefore, it is preferable that the second heat exchanger 22 be arranged so as not to overlap with the first flow path group X when viewed in the first direction. In particular, since the temperature near the inlet of the first refrigerant becomes the highest, it is preferable that the second heat exchanger 22 be arranged so as not to overlap with the inlet of the first refrigerant. Here, the second heat exchanger 22 is arranged so as not to overlap with the upper right region of the first heat exchanger 13.

[0168] Here, the flow of refrigerant in the first heat exchanger 13b during cooling operation will be described. As shown in FIG. 17 , when the first heat exchanger 13b functions as a radiator for the first refrigerant, the first refrigerant discharged from the first compressor 11 flows into the upper region 133a of the first header 133. The first refrigerant flowing through the plurality of first heat transfer tubes 131 belonging to the first flow path group X connected to the upper region 133a radiates a portion of its heat by exchanging heat with the outdoor air before reaching the upper region 134a of the second header 134. The first refrigerant then turns back in the upper region 134a and flows to the plurality of first heat transfer tubes 131 belonging to the second flow path group Y below. The first refrigerant flowing through the second flow path group Y radiates more heat by exchanging heat with the outdoor air again before reaching the intermediate region 133b of the first header 133. The first refrigerant turns back at the intermediate region 133b and flows into the plurality of first heat transfer tubes 131 belonging to the lower third flow path group Z. The first refrigerant flowing through the third flow path group Z again exchanges heat with the outside air, further releasing heat, and reaches the lower region 134b of the second header 134. The first refrigerant turns back at the lower region 134b and flows into the lower first heat transfer tubes 131 belonging to the lower fourth flow path W. The first refrigerant flowing through the fourth flow path W reaches the lower region 133c of the first header 133 and flows out of the first heat exchanger 13b.

[0169] (5-10) Modification 10 In the above embodiment, the heat source unit is of a side-blowing type, but the present invention is not limited to this. The heat source unit of this modification is of an upward-blowing type, as shown in FIG.

[0170] Specifically, the fan 43 is disposed above the first heat exchanger 13 and the second heat exchanger 22. When the fan 43 is operated, air is taken in through an opening provided on the side surface of the casing 41 and passes through the first heat exchanger 13 and the second heat exchanger 22. The air that has exchanged heat with the first refrigerant in the first heat exchanger 13 and the air that has exchanged heat with the second refrigerant in the second heat exchanger 22 is blown upward from an opening provided on the top surface of the casing 41. Therefore, the air flow direction F generated by the fan 43 includes the first direction in which the first heat exchanger 13 and the second heat exchanger 22 are stacked.

[0171] In this modified example, the second heat exchanger 22 also overlaps with the second region R2 of the first heat exchanger 13 when viewed in the first direction, which is the direction in which the second heat exchanger 22 overlaps with the first heat exchanger 13.

[0172] (5-11) Modification 11 In the above embodiment, the operation of the second circuit 20 is stopped during heating operation, but this is not limiting. The refrigeration apparatus of the present disclosure may operate the second circuit 20 during heating operation.

[0173] In the above embodiment, the second circuit 20 is operated during cooling operation, but this is not limiting. The refrigeration apparatus of the present disclosure may stop operation of the second circuit 20 during cooling operation.

[0174] (5-12) Modification 12 In the above embodiment, the refrigeration system 1 is described as an example in which one utilization unit 3 is connected to one heat source unit 2. However, the present modification is not limited to this. In the refrigeration system of this modification, multiple utilization units are connected to one heat source unit.

[0175] (5-13) Modification 13 In the above embodiment, the refrigeration apparatus 1 that performs both cooling and heating operations has been described as an example, but is not limited to this. The refrigeration apparatus of the present disclosure may also perform a dehumidifying operation. Furthermore, the refrigeration cycle apparatus of the present disclosure may be an air conditioning apparatus dedicated to cooling.

[0176] In the above embodiment, the heat source unit is applied to an air conditioner as a refrigeration device, but is not limited to this. The heat source unit of the present disclosure may also be applied to refrigeration devices such as a water heater, a floor heating device, and a refrigerator.

[0177] Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure as defined in the claims.

[0178] REFRIGERATION SYSTEM 1 : Refrigeration unit 2 : Heat source unit 3 : Utilization unit 10 : First circuit 11 : First compressor 13, 13a, 13b : First heat exchanger 20 : Second circuit 21 : Second compressor 22 : Second heat exchanger 30 : Third heat exchanger 41 : Casing 42 : Partition plate 43 : Fan 44 : Motor 45 : First support member 46 : Second support member 131, 131a : First heat transfer tube 132 : First fin R1 : First region R2 : Second region S1 : First chamber S2 : Second chamber

[0179] International Publication No. 2022 / 211078

Claims

1. a first circuit (10) in which a first refrigerant having a critical temperature of less than 45° C. circulates and which includes a first heat exchanger (13); a second circuit (20) in which a second refrigerant having a critical temperature of 45° C. or higher circulates and which includes a second heat exchanger; A heat source unit (2) of a refrigeration device (1) comprising: The first heat exchanger has a plurality of heat transfer tubes (131) arranged in the vertical direction; The second heat exchanger is disposed on the leeward side of the first heat exchanger; Equipped with The first heat exchanger and the second heat exchanger are stacked in a first direction (D), The first heat exchanger is The uppermost heat transfer tube (131a) and a first region (R1) above the uppermost heat transfer tube (131a); A second region (R2) below the uppermost heat transfer tube; Including, The second heat exchanger overlaps with the second region when viewed in the first direction.

2. A first compressor (11) that compresses the first refrigerant; A second compressor (21) that compresses the second refrigerant; a casing (41) that accommodates the first heat exchanger, the second heat exchanger, the first compressor, and the second compressor; a partition plate (42) that divides the inside of the casing into a first chamber (S1) in which the first heat exchanger and the second heat exchanger are arranged and a second chamber (S2) in which the first compressor and the second compressor are arranged; Further equipped with In the first chamber, the second heat exchanger is disposed on the second chamber side. The heat source unit according to claim 1 .

3. A fan (43) for blowing air to the second heat exchanger; A first support member (45) for supporting the fan; A second support member (46) that supports the second heat exchanger; Further comprising: The heat source unit according to claim 1 or 2.

4. the second support member is connected to a structural member; The heat source unit according to claim 3.

5. A fan (43) for blowing air to the second heat exchanger; A motor (44) for driving the fan; A first support member (45) for supporting the motor; Further equipped with The first support member further supports the second heat exchanger. The heat source unit according to claim 1 or 2.

6. The first heat exchanger further includes a first fin (131); The second heat exchanger has a second fin, The first fin and the second fin are spaced apart from each other. The heat source unit according to claim 1 or 2.

7. The first heat exchanger further includes a first fin (131); The second heat exchanger has a second fin, The first fin and the second fin are integral with each other. The heat source unit according to claim 1 or 2.

8. Further comprising a third heat exchanger (30) for exchanging heat between the first refrigerant and the second refrigerant. The heat source unit according to claim 1 or 2.

9. The second heat exchanger has a vertical length different from a horizontal length. The heat source unit according to claim 1 or 2.

10. The first circuit further includes a first compressor (11), The first compressor discharges the first refrigerant in a supercritical state. The heat source unit according to claim 1 or 2.

11. The first refrigerant includes a carbon dioxide refrigerant. The heat source unit according to claim 10.

12. The second refrigerant is flammable. The heat source unit according to claim 1 or 2.

13. The second refrigerant includes a hydrocarbon refrigerant. The heat source unit according to claim 12.

14. The heat source unit according to claim 1 or 2, A utilization unit (4) connected to the heat source unit; A refrigeration device (1).