Heat exchanger and refrigeration device

Abstract

Provided is a heat exchanger that can achieve an improvement in heat exchange efficiency. The heat exchanger comprises a first communication passage, a second communication passage, a first flow path, and a second flow path. The first communication passage allows a first fluid to flow along a first direction. The second communication passage allows a second fluid to flow along the first direction. The first flow path allows the first fluid to flow along the surface of a first plate included in a plurality of plates. The second flow path allows the second fluid to flow along the surface of a second plate included in the plurality of plates. The first plate and the second plate each have a recess, a first outer hole and a second outer hole, and a first inner hole and a second inner hole. The first inner hole and the second outer hole form a part of the first communication passage. The second inner hole and the first outer hole form a part of the second communication passage. The first outer hole, the second outer hole, the first inner hole, and the second inner hole are formed on the same straight line when viewed in the first direction.

Description

Heat Exchanger, Refrigeration Device

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

[0002] Patent Document 1 (Japanese Unexamined Patent Publication No. 2023-51241) discloses a plate heat exchanger. A first heat transfer plate and a second heat transfer plate included in the plate heat exchanger of Patent Document 1 are formed such that a heat transfer region, two flow ports, and two through holes are aligned in a straight line. A fluid serving as a heat medium flows in from one flow port, passes through the heat transfer region, and then flows out from the other flow port.

[0003] In the plate heat exchanger disclosed in Patent Document 1, the flow port of the first heat transfer plate is formed at a position between the through hole and the heat transfer region. Further, the flow port of the second heat transfer plate is formed at a position farther from the heat transfer region than the through hole is.

[0004] In the case of the plate heat exchanger disclosed in Patent Document 1, in the second heat transfer plate, the refrigerant flowing out from one flow port comes into contact with the through hole before reaching the heat transfer region, and thus cannot flow linearly toward the other through hole. In contrast, in the first heat transfer plate, the refrigerant flowing out from one flow hole flows linearly toward the other flow hole without coming into contact with the through hole.

[0005] As described above, in the plate heat exchanger disclosed in Patent Document 1, uneven flow rate (flow maldistribution) occurs due to the difference in the flow paths of the refrigerant in the heat transfer region. As a result, when viewed in the thickness direction of the plate heat exchanger, the overlapping area between the region where a large amount of one refrigerant flows and the region where a large amount of the other refrigerant flows becomes small, which causes a problem that sufficient heat exchange efficiency cannot be ensured.

[0006] An object of the present disclosure is to provide a heat exchanger that can improve heat exchange efficiency.

[0007] A heat exchanger according to a first aspect is a heat exchanger in which a plurality of plates are stacked in a first direction. The heat exchanger includes a first communication passage, a second communication passage, a first flow path, and a second flow path.

[0008] The first connecting passage allows the first fluid to flow along a first direction. The second connecting passage allows the second fluid to flow along a first direction. The first flow path allows the first fluid to flow along the surface of the first plate, which is contained in a plurality of plates. The second flow path allows the second fluid to flow along the surface of the second plate, which is contained in a plurality of plates. The first plate and the second plate have recesses, a first outer hole and a second outer hole, and a first inner hole and a second inner hole.

[0009] The first outer hole and the second outer hole are formed so as to sandwich the recess when viewed from the first direction. The first inner hole is formed between the first outer hole and the recess when viewed from the first direction. The second inner hole is formed between the second outer hole and the recess when viewed from the first direction.

[0010] The recess in the first plate is blocked by other plates included in a plurality of adjacent stacked plates to form a first channel. The recess in the second plate is blocked by other plates included in a plurality of adjacent stacked plates to form a second channel. The first inner hole and the second outer hole constitute part of the first connecting passage. The second inner hole and the first outer hole constitute part of the second connecting passage. The first outer hole, the second outer hole, the first inner hole, and the second inner hole are formed on the same straight line when viewed from a first direction.

[0011] In this heat exchanger, neither the first fluid nor the second fluid can flow linearly. Therefore, the fluid flow rate tends to be higher on the outer side of the recess in the width direction of both the first and second plates compared to other parts. As a result, in a first-direction view, the region where the first fluid flows most and the region where the second fluid flows most can overlap almost entirely. Consequently, with this heat exchanger, the region where the first fluid flows and the region where the second fluid flows easily overlap, improving heat exchange efficiency compared to conventional designs.

[0012] The heat exchanger in the second view is the heat exchanger in the first view, wherein the first fluid that flows out from the first inner hole flows through the first flow path and then flows into the second outer hole.

[0013] This heat exchanger suppresses the deterioration of heat exchange efficiency caused by fluid flow deviation.

[0014] The heat exchanger in the third view is a heat exchanger in the first or second view, wherein the first fluid flowing out from the first inner hole is in a gas-liquid two-phase state.

[0015] This heat exchanger does not have inner holes that the first fluid comes into contact with before flowing into the recess after flowing out of the first inner hole. Therefore, this heat exchanger suppresses the occurrence of flow deviation caused by the first fluid flowing out of the first inner hole coming into contact with the inner hole.

[0016] The heat exchanger in the fourth view is any of the heat exchangers in the first view or the third view, wherein the area of ​​the second outer hole is larger than the area of ​​the second inner hole.

[0017] According to this heat exchanger, the first fluid that flows out from the first inner hole and comes into contact with the second inner hole can easily flow into the second outer hole.

[0018] The heat exchanger in the fifth aspect is the heat exchanger in the first aspect, wherein the first fluid that flows out from the second outer hole flows through the first flow path and then flows into the first inner hole.

[0019] In this heat exchanger, neither the first fluid nor the second fluid can flow in a straight line. Therefore, in a first-direction view, the region where the first fluid flows most and the region where the second fluid flows most overlap almost entirely. Consequently, this heat exchanger can also suppress the deterioration of heat exchange efficiency caused by fluid flow deviation.

[0020] The heat exchanger in the sixth aspect is the heat exchanger in the fifth aspect, wherein the first fluid flowing out from the first flow path is in a gaseous state.

[0021] This heat exchanger does not have an inner hole that the first fluid comes into contact with before flowing out of the first flow path and into the first inner hole. Therefore, with this heat exchanger, pressure loss to the first fluid in the gas phase due to contact with the inner hole is suppressed.

[0022] The heat exchanger in the seventh aspect is one of the heat exchangers in the first aspect to the fifth aspect, and the first fluid is propane.

[0023] The refrigeration system according to the eighth aspect comprises one of the heat exchangers according to the first aspect or the seventh aspect.

[0024] This is a configuration diagram showing a refrigeration system 1 equipped with a first heat exchanger 100. This is an exploded view of the first heat exchanger 100. This is an enlarged cross-sectional view of the first heat exchanger 100. This is a schematic plan view showing the flow of the first and second refrigerants during heating operation. This is a schematic plan view showing the flow of refrigerants in a conventional plate heat exchanger. This is a configuration diagram showing a refrigeration system 2 equipped with the first heat exchanger 100. This is a schematic plan view showing the flow of the first and second refrigerants in a second embodiment.

[0025] <First Embodiment> (1) Refrigeration System 1 First, a refrigeration system 1 equipped with a first heat exchanger 100 according to the first embodiment of this disclosure will be described. Figure 1 is a schematic configuration diagram showing a refrigeration system 1 equipped with a first heat exchanger 100. The refrigeration system 1 is a dual refrigerant cycle system that performs heating and cooling operations on an air-conditioned space (not shown), such as the interior of a building, by executing a vapor compression cycle.

[0026] The refrigeration system 1 heats or cools water and uses this water to perform heating and cooling operations in a space to be air-conditioned (not shown). The refrigeration system 1 includes a first heat exchanger 100, a second heat exchanger 300, a first refrigerant circuit 10, a second refrigerant circuit 20, a water circuit 30, and a control unit 40. As will be described in detail later, the refrigeration system 1 is configured such that a first refrigerant circulates in the first refrigerant circuit 10, a second refrigerant with a lower boiling point than the first refrigerant circulates in the second refrigerant circuit 20, and water circulates in the water circuit 30. Although not limited to this, in this embodiment the water circuit 30 is installed indoors and the second refrigerant circuit 20 is installed outdoors. The first refrigerant circuit 10 may be installed indoors or outdoors, or a part of it may be installed indoors or outdoors.

[0027] (1-1) First heat exchanger 100 The first heat exchanger 100 causes heat exchange between the first refrigerant circulating in the first refrigerant circuit 10 and the second refrigerant circulating in the second refrigerant circuit 20. The first heat exchanger 100 has first flow ports 141a, 141b, second flow ports 142a, 142b, a first flow path 210, and a second flow path 220.

[0028] The first flow path 210 is a flow path through which the first refrigerant flows. The first flow path 210 is provided between the first flow port 141a and the first flow port 141b. The second flow path 220 is a flow path through which the second refrigerant flows. The second flow path 220 is formed between the second flow port 142a and the second flow port 142b. The first refrigerant flowing through the first flow path 210 exchanges heat with the second refrigerant flowing through the second flow path 220. The detailed structure of the first heat exchanger 100 will be described later.

[0029] (1-2) Second heat exchanger 300 The second heat exchanger 300 causes heat exchange between the first refrigerant circulating in the first refrigerant circuit 10 and the water circulating in the water circuit 30. The second heat exchanger 300 has first flow ports 341a, 341b, second flow ports 342a, 342b, a first flow path 410, and a second flow path 420.

[0030] The first flow path 410 is a flow path through which the first refrigerant flows. The first flow path 410 is provided between the first flow port 341a and the first flow port 341b. The second flow path 420 is a flow path through which water flows. The second flow path 420 is formed between the second flow port 342a and the second flow port 342b. The first refrigerant flowing through the first flow path 410 exchanges heat with the water flowing through the second flow path 420.

[0031] (1-3) First Refrigerant Circuit 10 In the first refrigerant circuit 10, the first refrigerant is heated or cooled. The first refrigerant circuit 10 consists of a compressor 11, a four-way switching valve 12, an expansion valve 13, a first flow path 210 of the first heat exchanger 100, and a first flow path 410 of the second heat exchanger 300. The compressor 11, the four-way switching valve 12, the expansion valve 13, the first flow path 210 of the first heat exchanger 100, and the first flow path 410 of the second heat exchanger 300 are connected by piping, and the first refrigerant circulates inside them. In this embodiment, the first refrigerant is propane. The first refrigerant is an example of the first fluid.

[0032] The compressor 11 draws in the low-pressure first refrigerant from the first refrigerant circuit 10 through the suction port 11a, compresses it, and discharges it as high-pressure first refrigerant from the discharge port 11b.

[0033] The four-way switching valve 12 has a first port 12a, a second port 12b, a third port 12c, and a fourth port 12d. Based on instructions from the control unit 40, the four-way switching valve 12 switches between a first state and a second state in which the communication state of the first port 12a, second port 12b, third port 12c, and fourth port 12d is different. In the first state, the first port 12a and the second port 12b are in communication, and the third port 12c and the fourth port 12d are in communication. In the second state, the first port 12a and the fourth port 12d are in communication, and the second port 12b and the third port 12c are in communication.

[0034] The first port 12a is connected to the discharge section 11b of the compressor 11. The second port 12b is connected to the first flow port 341a of the second heat exchanger 300. The third port 12c is connected to the suction section 11a of the compressor 11. The fourth port 12d is connected to the first flow port 141b of the first heat exchanger 100.

[0035] The expansion valve 13 functions as a pressure reducing device that adjusts the flow rate of the first refrigerant circulating in the first refrigerant circuit 10 and reduces the pressure of the first refrigerant.

[0036] One end of the expansion valve 13 is connected to the first flow port 141a of the first heat exchanger 100. The other end of the expansion valve 13 is connected to the first flow port 341b of the second heat exchanger 300.

[0037] (1-4) Second Refrigerant Circuit 20 In the second refrigerant circuit 20, the second refrigerant is heated or cooled. The second refrigerant circuit 20 consists of a compressor 21, a four-way switching valve 22, an expansion valve 23, a heat source heat exchanger 24, and the second flow path 220 of the first heat exchanger 100. The compressor 21, the four-way switching valve 22, the expansion valve 23, the heat source heat exchanger 24, and the second flow path 220 of the first heat exchanger 100 are connected by piping, and the second refrigerant circulates inside them. In this embodiment, the second refrigerant is carbon dioxide. The second refrigerant is an example of a second fluid.

[0038] The compressor 21 draws in the low-pressure second refrigerant from the second refrigerant circuit 20 through the suction port 21a, compresses it, and discharges it as high-pressure second refrigerant from the discharge port 21b.

[0039] The four-way switching valve 22 includes a first port 22a, a second port 22b, a third port 22c, and a fourth port 22d. Based on instructions from the control unit 40, the four-way switching valve 22 switches between a first state and a second state in which the communication states of the first port 22a, the second port 22b, the third port 22c, and the fourth port 22d are different. In the first state, the first port 22a communicates with the second port 22b, and the third port 22c communicates with the fourth port 22d. In the second state, the first port 22a communicates with the fourth port 22d, and the second port 22b communicates with the third port 22c.

[0040] The first port 22a is connected to a discharge portion 21b of the compressor 21. The second port 22b is connected to a second flow port 142b of the first heat exchanger 100. The third port 22c is connected to a suction portion 21a of the compressor 21. The fourth port 22d is connected to one end of the heat source heat exchanger 24.

[0041] The expansion valve 23 functions as a pressure reducing device that adjusts the flow rate of the second refrigerant circulating through the second refrigerant circuit 20 and reduces the pressure of the second refrigerant.

[0042] One end of the expansion valve 23 is connected to a second flow port 142a of the first heat exchanger 100. The other end of the expansion valve 23 is connected to the other end of the heat source heat exchanger 24.

[0043] The heat source heat exchanger 24 causes heat exchange between the second refrigerant circulating through the second refrigerant circuit 20 and a heat source (e.g., outdoor air).

[0044] (1-5) Water circuit 30 In the water circuit 30, water that has exchanged heat with the first refrigerant circulates. The water circuit 30 is constituted by a water circulation pump 31, a water storage tank 32, a second flow path 420 of the second heat exchanger 300, and a utilization heat exchanger 33. The water circulation pump 31, the water storage tank 32, the second flow path 420 of the second heat exchanger 300, and the utilization heat exchanger 33 are connected by pipes, and water circulates inside the pipes.

[0045] The water circulation pump 31 circulates water inside the water circuit 30. The water circulation pump 31 sucks water inside the water circuit 30 from a suction portion 31a and discharges the water from a discharge portion 31b.

[0046] The suction part 31a is connected to the second flow port 342b of the second heat exchanger 300.

[0047] The water storage tank 32 stores water heated or cooled by the second heat exchanger 300, thereby heating or cooling the air in the air-conditioned space (in other words, performing heating or cooling). The water storage tank 32 has a water intake part 32a that takes in water circulating through the water circuit 30, and a drainage part 32b that discharges the stored water.

[0048] The water intake part 32a is connected to the discharge part 31b of the water circulation pump 31. The drainage part 32b is connected to the second flow port 342a of the second heat exchanger 300.

[0049] The utilization heat exchanger 33 enables heat exchange between the water circulating through the water circuit 30 and the air in the air-conditioned space (not shown in the drawings). The utilization heat exchanger 33 is arranged inside the air-conditioned space such that the water passing through the inside thereof can exchange heat with the air in the air-conditioned space. One end of the utilization heat exchanger 33 is connected to the discharge part 31b of the water circulation pump 31. The other end of the utilization heat exchanger 33 is connected to the second flow port 342a of the second heat exchanger 300. The number of utilization heat exchangers 33 included in the water circuit 30 may be one, or may be two or more as shown in FIG. 1.

[0050] (1-6) Control Unit 40 The control unit 40 controls the compressors 11 and 21, the four-way switching valves 12 and 22, the expansion valves 13 and 23, and the water circulation pump 31. Although not shown in the drawings, the control unit 40 is electrically connected to the compressors 11 and 21, the four-way switching valves 12 and 22, the expansion valves 13 and 23, and the water circulation pump 31 so as to be capable of transmitting and receiving control signals.

[0051] (1-7) Operation of Refrigeration Device 1 The refrigeration device 1 performs a heating operation and a cooling operation.

[0052] (1-7-1) Heating Operation The heating operation is an operation in which the refrigeration device 1 heats the water in the water circuit 30. In the heating operation, the control unit 40 sets the four-way switching valves 12 and 22 to a first state, drives the compressors 11 and 21 and the water circulation pump 31, and controls the opening degrees of the expansion valves 13 and 23.

[0053] (1-7-1-1) Second Refrigerant Circuit 20 The compressor 21 draws in the second refrigerant in the low-pressure gas phase state from the suction port 21a and discharges it as the second refrigerant in the high-pressure gas phase state from the discharge port 21b. The second refrigerant in the high-pressure gas phase state passes through the four-way switching valve 22 in the order of the first port 22a and the second port 22b and reaches the second flow path 220 of the first heat exchanger 100 from the second flow port 142b. In the second flow path 220 of the first heat exchanger 100, the second refrigerant in the high-pressure gas phase state condenses to become the second refrigerant in the high-pressure liquid phase state. At this time, the second refrigerant releases heat to the first refrigerant passing through the first flow path 210. The second refrigerant in the high-pressure liquid phase state reaches the expansion valve 23. The expansion valve 23, set to an appropriate opening degree, reduces the pressure of the second refrigerant in the high-pressure liquid phase state to become the second refrigerant in a low-pressure gas-liquid two-phase state. The second refrigerant, in a low-pressure gas-liquid two-phase state, evaporates in the heat source heat exchanger 24 to become the second refrigerant in a low-pressure gas phase state. At this time, the second refrigerant absorbs heat from the heat source. The second refrigerant in the low-pressure gas phase state passes through the four-way switching valve 22 in the order of the fourth port 22d and the third port 22c, and is then drawn into the compressor 21 from the suction section 21a.

[0054] (1-7-1-2) First refrigerant circuit 10 The compressor 11 draws in the first refrigerant in a low-pressure gas phase state from the intake port 11a and discharges it as the first refrigerant in a high-pressure gas phase state from the discharge port 11b. The first refrigerant in the high-pressure gas phase state passes through the four-way switching valve 12 in the order of the first port 12a and the second port 12b and reaches the first flow path 410 of the second heat exchanger 300 from the first flow port 341a. In the first flow path 410 of the second heat exchanger 300, the first refrigerant in the high-pressure gas phase state condenses to become the first refrigerant in a high-pressure liquid phase state. At this time, the first refrigerant releases heat to the water passing through the second flow path 420. The first refrigerant in the high-pressure liquid phase state reaches the expansion valve 13. The expansion valve 13, set to an appropriate opening degree, reduces the pressure of the first refrigerant in the high-pressure liquid phase state to become the first refrigerant in a low-pressure gas-liquid two-phase state. The first refrigerant, in a low-pressure gas-liquid two-phase state, passes through the first flow port 141a of the first heat exchanger 100, then evaporates in the first flow path 210 to become the first refrigerant in a low-pressure gas phase state. At this time, the first refrigerant absorbs heat from the second refrigerant passing through the second flow path 220. The first refrigerant in the low-pressure gas phase state passes through the four-way switching valve 12 in the order of the fourth port 12d and the third port 12c, and is then drawn into the compressor 11 from the suction section 11a.

[0055] (1-7-1-3) Water circuit 30 The water circulation pump 31 draws in water circulating in the water circuit 30 from the intake section 31a and discharges it from the discharge section 31b. A portion of the discharged water passes through the intake section 32a and is stored in the water storage tank 32, while the remainder passes through the heat exchanger 33. Both the water stored in the water storage tank 32 and the water that passes through the heat exchanger 33 release heat into the air in the space to be air-conditioned. In other words, the water stored in the water storage tank 32 and the water that passes through the heat exchanger 33 heat the air in the space to be air-conditioned. The water stored in the water storage tank 32 passes through the drain section 32b and then reaches the second flow path 420 through the second flow port 342a of the second heat exchanger 300. The water that has passed through the heat exchanger 33 reaches the second flow path 420 through the second flow port 342a of the second heat exchanger 300. The water that reaches the second flow path 420 of the second heat exchanger 300 absorbs heat from the first refrigerant passing through the first flow path 410. The water that has absorbed heat is then drawn into the water circulation pump 31 from the suction section 31a.

[0056] (1-7-2) Cooling Operation Cooling operation is the operation in which the refrigeration unit 1 cools the water in the water circuit 30. In cooling operation, the control unit 40 sets the four-way switching valves 12 and 22 to the second state, drives the compressors 11 and 21 and the water circulation pump 31, and controls the opening degree of the expansion valves 13 and 23.

[0057] (1-7-2-1) Second refrigerant circuit 20 The compressor 21 draws in the second refrigerant in the low-pressure gas phase state from the second refrigerant circuit 20 through the suction port 21a and discharges it as the second refrigerant in the high-pressure gas phase state from the discharge port 21b. The second refrigerant in the high-pressure gas phase state passes through the four-way switching valve 22 in the order of the first port 22a and the fourth port 22d to reach the heat source heat exchanger 24. In the heat source heat exchanger 24, the second refrigerant in the high-pressure gas phase state condenses to become the second refrigerant in the high-pressure liquid phase state. At this time, the second refrigerant releases heat to the heat source. The second refrigerant in the high-pressure liquid phase state reaches the expansion valve 23. The expansion valve 23, set to an appropriate opening degree, reduces the pressure of the second refrigerant in the high-pressure liquid phase state to become the second refrigerant in a low-pressure gas-liquid two-phase state. The second refrigerant, in a low-pressure gas-liquid two-phase state, passes through the second flow port 142a of the first heat exchanger 100, then evaporates in the second flow path 220 to become the second refrigerant in a low-pressure gas phase state. At this time, the second refrigerant absorbs heat from the first refrigerant passing through the second flow path 220. The second refrigerant in the low-pressure gas phase state passes through the four-way switching valve 22 in the order of the second port 22b and the third port 22c, and is then drawn into the compressor 21 from the suction section 21a.

[0058] (1-7-2-2) First Refrigerant Circuit 10 The compressor 11 draws in the first refrigerant in a low-pressure gas phase state from the intake port 11a and discharges it as the first refrigerant in a high-pressure gas phase state from the discharge port 11b. The first refrigerant in the high-pressure gas phase state passes through the four-way switching valve 12 in the order of the first port 12a and the fourth port 12d and reaches the first flow path 210 of the first heat exchanger 100 from the first flow port 141b. In the first flow path 210 of the first heat exchanger 100, the first refrigerant in the high-pressure gas phase state condenses to become the first refrigerant in a high-pressure liquid phase state. At this time, the first refrigerant releases heat to the second refrigerant passing through the second flow path 220. The first refrigerant in the high-pressure liquid phase state reaches the expansion valve 13. The expansion valve 13, set to an appropriate opening degree, reduces the pressure of the first refrigerant in the high-pressure liquid phase state to become the first refrigerant in a low-pressure gas-liquid two-phase state. The first refrigerant, in a low-pressure gas-liquid two-phase state, passes through the first flow port 341b of the second heat exchanger 300, then evaporates in the first flow path 410 to become the first refrigerant in a low-pressure gas phase state. At this time, the first refrigerant absorbs heat from the second refrigerant passing through the second flow path 420. The first refrigerant in the low-pressure gas phase state passes through the four-way switching valve 12 in the order of the second port 12b and the third port 12c, and is then drawn into the compressor 11 from the suction section 11a.

[0059] (1-7-2-3) Water circuit 30 The water circulation pump 31 draws in water circulating in the water circuit 30 from the intake section 31a and discharges it from the discharge section 31b. A portion of the discharged water passes through the intake section 32a and is stored in the water storage tank 32, while the remainder passes through the heat exchanger 33. Both the water stored in the water storage tank 32 and the water that passes through the heat exchanger 33 absorb heat from the air in the space to be air-conditioned. In other words, the water stored in the water storage tank 32 and the water that passes through the heat exchanger 33 cool the air in the space to be air-conditioned. The water stored in the water storage tank 32 passes through the drain section 32b and then reaches the second flow path 420 through the second flow port 342a of the second heat exchanger 300. The water that has passed through the heat exchanger 33 reaches the second flow path 420 through the second flow port 342a of the second heat exchanger 300. The water that reaches the second flow path 420 of the second heat exchanger 300 releases heat to the first refrigerant passing through the first flow path 410. The water that has released heat is then drawn into the water circulation pump 31 from the suction section 31a.

[0060] (2) First heat exchanger 100 (2-1) Overall configuration The first heat exchanger 100 is a plate heat exchanger composed of multiple plates. Figure 2 is an exploded view of the first heat exchanger 100. Figure 3 is an enlarged cross-sectional view of the first heat exchanger 100. Specifically, Figure 3 is an enlarged cross-sectional view showing the area around the first flow port 141b and the second flow port 142b. In Figure 3, the direction of flow of the first refrigerant and the second refrigerant during heating operation is indicated by arrows. In Figure 2, for convenience, only a portion of the first recess 114 and the second recess 134 are shown.

[0061] The first heat exchanger 100 comprises a plurality of first heat transfer plates 110, a plurality of partition walls 120, a plurality of second heat transfer plates 130, a first end frame 140, and a second end frame 150. The first heat exchanger 100 has a first flow path 210 and a second flow path 220 inside.

[0062] The first heat transfer plate 110, the partition wall 120, and the second heat transfer plate 130 have the same outer shape and size. In this embodiment, as shown in Figure 2, the outer shape of the first heat transfer plate 110, the partition wall 120, the second heat transfer plate 130, the first end frame 140, and the second end frame 150 is strip-shaped.

[0063] Multiple first heat transfer plates 110 and multiple second heat transfer plates 130 are alternately stacked between a first end frame 140 and a second end frame 150, with a partition wall 120 in between. The number of each of the multiple first heat transfer plates 110 and multiple second heat transfer plates 130 is not particularly limited and is set appropriately according to the required performance. The first end frame 140, the first heat transfer plates 110, the partition wall 120, the second heat transfer plates 130, and the second end frame 150 are, for example, integrally joined by diffusion bonding, although this is not limited to these methods.

[0064] In the following explanation, for convenience, the longitudinal direction of the first heat transfer plate 110, the partition wall 120, and the second heat transfer plate 130 may be referred to as the longitudinal direction DL. Also, the width direction of the first heat transfer plate 110, the partition wall 120, and the second heat transfer plate 130 may be referred to as the width direction DW. Furthermore, the thickness direction (in other words, the stacking direction) of the first heat transfer plate 110, the partition wall 120, and the second heat transfer plate 130 may be referred to as the thickness direction DT (see the arrows shown in some of the figures). In addition, the up and down directions mentioned in the following explanation correspond to "up" and "down" as shown in some of the figures.

[0065] The first heat exchanger 100 is an example of a heat exchanger. The thickness direction DT is an example of a first direction. The second flow path 220 is an example of a flow path.

[0066] (2-2) Detailed Configuration (2-2-1) First Heat Transfer Plate 110 The first heat transfer plate 110, together with the adjacent stacked partition wall 120, forms a first flow channel 210. The first heat transfer plate 110 has two outer holes 111, two inner holes 112, two headers 113, and a plurality of first recesses 114. The first heat transfer plate 110 is an example of a first plate.

[0067] The two outer holes 111 include a first outer hole 111a and a second outer hole 111b. The first outer hole 111a and the second outer hole 111b are formed so as to sandwich the first recess 114 when viewed in the thickness direction DT (plan view of the first heat transfer plate 110). The first outer hole 111a is formed on the lower side of the first recess 114. The second outer hole 111b is formed on the upper side of the first recess 114. The first outer hole 111a is a through hole through which the second refrigerant flows. The second outer hole 111b is a through hole through which the first refrigerant flows. Hereinafter, the first outer hole 111a and the second outer hole 111b may be collectively referred to as the outer hole 111. The outer hole 111 penetrates the first heat transfer plate 110 along the thickness direction DT. The outer hole 111 is circular when viewed in the thickness direction DT.

[0068] The two inner holes 112 include a first inner hole 112a and a second inner hole 112b. The first inner hole 112a is formed between the first outer hole 111a and the first recess 114 in a view in the thickness direction DT. The second inner hole 112b is formed between the second outer hole 111b and the first recess 114 in a view in the thickness direction DT. The first inner hole 112a is a through hole through which the first refrigerant flows. The second inner hole 112b is a through hole through which the second refrigerant flows. Hereinafter, the first inner hole 112a and the second inner hole 112b may be collectively referred to as the inner hole 112. The inner hole 112 penetrates the first heat transfer plate 110 along the thickness direction DT. The inner hole 112 is circular in a view in the thickness direction DT.

[0069] The first outer hole 111a, the second outer hole 111b, the first inner hole 112a, and the second inner hole 112b are formed to lie on the same straight line L (see Figure 2) when viewed in the thickness direction DT. In other words, at least a portion of each of the first outer hole 111a, the second outer hole 111b, the first inner hole 112a, and the second inner hole 112b is formed to intersect the straight line L when viewed in the thickness direction DT.

[0070] In this embodiment, as shown in Figure 2, the area of ​​the first outer hole 111a in the thickness direction DT view is smaller than that of the first inner hole 112a. Also, the area of ​​the second outer hole 111b in the thickness direction DT view is larger than that of the second inner hole 112b.

[0071] The two headers 113 include a first header 113a and a second header 113b. Hereafter, the first header 113a and the second header 113b may be collectively referred to as header 113. Header 113 has multiple protrusions 113i on its surface (see Figure 3).

[0072] The first header 113a connects the first inner hole 112a and the first recess 114, and diverts a portion of the first refrigerant flowing through the first communication passage 161a (described later) to the first recess 114. The surface of the first header 113a is flush with the bottom 114b of the first recess 114. In a view in the thickness direction DT, the first header 113a does not overlap with the first outer hole 111a, but overlaps with the first inner hole 112a. More specifically, in a view in the thickness direction DT, the first header 113a is a rectangular region enclosed by a boundary 110b extending in the width direction DW between the first outer hole 111a and the first inner hole 112a, both end edges 110es in the width direction DW, and the lower ends of the plurality of first recesses 114.

[0073] The second header 113b connects the second outer hole 111b and the first recess 114, and diverts a portion of the first refrigerant flowing through the first communication passage 161b (described later) to the first recess 114. The surface of the second header 113b is flush with the bottom 114b of the first recess 114. In a view in the thickness direction DT, the second header 113b overlaps with the second outer hole 111b and the second inner hole 112b. More specifically, in a view in the thickness direction DT, the second header 113b is a rectangular region enclosed by the upper edge 110eu of the first heat transfer plate 110, both end edges 110es in the width direction DW, and the upper ends of the multiple first recesses 114.

[0074] The second header 113b has a sealing portion 113s. The sealing portion 113s suppresses the inflow of the second refrigerant flowing through the second communication passage 162b and the second inner hole 112b into the second header 113b. The sealing portion 113s is a protruding portion formed to surround the second inner hole 112b in a view in the thickness direction DT. The sealing portion 113s protrudes from the surface of the second header 113b to the same height as the wall portion 114a (described later) separating the adjacent first recess 114.

[0075] The first recess 114 is a groove through which the first refrigerant, which has been diverted from the header 113, flows. Multiple first recesses 114 are formed in the center of the first heat transfer plate 110 in the longitudinal direction DL. The first recess 114 is a linear groove that extends along the longitudinal direction DL without branching. Multiple first recesses 114 are formed at predetermined intervals along the width direction DW (not limited to, but in this embodiment, about 130). Adjacent first recesses 114 are separated by a wall portion 114a. One end of the first recess 114 is in contact with the first header 113a, and the other end is in contact with the second header 113b.

[0076] (2-2-2) Partition wall 120 The partition wall 120 separates the first heat transfer plate 110 and the second heat transfer plate 130 in the thickness direction DT. The partition wall 120 is a flat plate with two outer holes 121 and two inner holes 122 formed therein.

[0077] The two outer holes 121 include a first outer hole 121a and a second outer hole 121b. Hereafter, the first outer hole 121a and the second outer hole 121b may be collectively referred to as the outer hole 121. The outer holes 121 penetrate the partition wall 120 along the thickness direction DT.

[0078] The first outer hole 121a is a through-hole through which the second refrigerant flows. The first outer hole 121a has the same shape and size as the first outer hole 111a of the first heat transfer plate 110. Furthermore, when the partition wall 120 is stacked on the first heat transfer plate 110, the first outer hole 121a is formed in a position that overlaps with the first outer hole 111a of the first heat transfer plate 110.

[0079] The second outer hole 121b is a through-hole through which the first refrigerant flows. The second outer hole 121b has the same shape and size as the second outer hole 111b of the first heat transfer plate 110. Furthermore, when the partition wall 120 is stacked on the first heat transfer plate 110, the second outer hole 121b is formed in a position that overlaps with the second outer hole 111b of the first heat transfer plate 110.

[0080] The two inner holes 122 include a first inner hole 122a and a second inner hole 122b. Hereafter, the first inner hole 122a and the second inner hole 122b may be collectively referred to as the inner hole 122. The inner holes 122 penetrate the partition wall 120 along the thickness direction DT.

[0081] The first inner hole 122a is a through-hole through which the first refrigerant flows. The first inner hole 122a has the same shape and size as the first inner hole 112a of the first heat transfer plate 110. Furthermore, when the partition wall 120 is stacked on the first heat transfer plate 110, the first inner hole 122a is formed in a position that overlaps with the first inner hole 112a of the first heat transfer plate 110.

[0082] The inner hole 122 is a through-hole through which the second refrigerant flows. The second inner hole 122b has the same shape and size as the second inner hole 112b of the first heat transfer plate 110. Furthermore, when the partition wall 120 is stacked on the first heat transfer plate 110, the second inner hole 122b is formed in a position that overlaps with the second inner hole 112b of the first heat transfer plate 110.

[0083] The first outer hole 121a, the second outer hole 121b, the first inner hole 122a, and the second inner hole 122b are also formed to lie on the same straight line in the thickness direction DT view, similar to the first outer hole 111a, the second outer hole 111b, the first inner hole 112a, and the second inner hole 112b.

[0084] (2-2-3) Second heat transfer plate 130 The second heat transfer plate 130 is adjacent to the partition wall 120 on the side opposite to the first heat transfer plate 110. Together with the adjacently stacked partition wall 120, the second heat transfer plate 130 forms a second flow channel 220. The second heat transfer plate 130 has two outer holes 131, two inner holes 132, two headers 133, and a plurality of second recesses 134. The second heat transfer plate 130 is an example of a second plate.

[0085] The two outer holes 131 include a first outer hole 131a and a second outer hole 131b. The first outer hole 131a and the second outer hole 131b are formed so as to sandwich the second recess 134 when viewed in the thickness direction DT. The first outer hole 131a is formed on the lower side of the second recess 134. The second outer hole 131b is formed on the upper side of the second recess 134. The first outer hole 131a is a through hole through which the second refrigerant flows. The second outer hole 131b is a through hole through which the first refrigerant flows. Hereinafter, the first outer hole 131a and the second outer hole 131b may be collectively referred to as the outer hole 131. The outer hole 131 penetrates the second heat transfer plate 130 along the thickness direction DT.

[0086] The first outer hole 131a has the same shape and size as the first outer hole 111a of the first heat transfer plate 110 and the first outer hole 121a of the partition wall 120. Furthermore, when the partition wall 120 is stacked on the second heat transfer plate 130, the first outer hole 131a is formed in a position that overlaps with the first outer hole 121a of the partition wall 120. The second outer hole 131b has the same shape and size as the second outer hole 111b of the first heat transfer plate 110 and the second outer hole 121b of the partition wall 120. Furthermore, when the partition wall 120 is stacked on the second heat transfer plate 130, the second outer hole 131b is formed in a position that overlaps with the second outer hole 121b of the partition wall 120.

[0087] The two inner holes 132 include a first inner hole 132a and a second inner hole 132b. The first inner hole 132a is formed between the first outer hole 131a and the second recess 134 in a view in the thickness direction DT. The second inner hole 132b is formed between the second outer hole 131b and the second recess 134 in a view in the thickness direction DT. The first inner hole 132a is a through hole through which the first refrigerant flows. The second inner hole 132b is a through hole through which the second refrigerant flows. Hereafter, the first inner hole 132a and the second inner hole 132b may be collectively referred to as the inner hole 132. The inner hole 132 penetrates the second heat transfer plate 130 along the thickness direction DT.

[0088] The first inner hole 132a has the same shape and size as the first inner hole 112a of the first heat transfer plate 110 and the first inner hole 122a of the partition wall 120. Furthermore, when the partition wall 120 is stacked on the second heat transfer plate 130, the first inner hole 132a is formed in a position that overlaps with the first inner hole 122a of the partition wall 120. The second inner hole 132b has the same shape and size as the second inner hole 112b of the first heat transfer plate 110 and the second inner hole 122b of the partition wall 120. Furthermore, when the partition wall 120 is stacked on the second heat transfer plate 130, the second inner hole 132b is formed in a position that overlaps with the second inner hole 122b of the partition wall 120.

[0089] The first outer hole 131a, the second outer hole 131b, the first inner hole 132a, and the second inner hole 132b are also formed to lie on the same straight line in the thickness direction DT, similar to the first outer hole 111a, the second outer hole 111b, the first inner hole 112a, and the second inner hole 112b.

[0090] The two headers 133 include a first header 133a and a second header 133b. Hereafter, the first header 133a and the second header 133b may be collectively referred to as header 133. Header 113 has multiple protrusions 133i on its surface (see Figure 3).

[0091] The first header 133a connects the first outer hole 131a and the second recess 134, and diverts a portion of the second refrigerant flowing through the second communication passage 162a (described later) to the second recess 134. The surface of the first header 133a is flush with the bottom 134b of the second recess 134. In a view in the thickness direction DT, the first header 133a overlaps with the first outer hole 131a and the first inner hole 132a. More specifically, in a view in the thickness direction DT, the first header 133a is a rectangular region enclosed by the lower edge 130eb of the second heat transfer plate 130, both end edges 130es in the width direction DW, and the lower ends of the multiple second recesses 134.

[0092] The first header 133a has a sealing portion 133s. The sealing portion 133s suppresses the inflow of the first refrigerant flowing through the second communication passage 162a and the first inner hole 132a into the first header 133a. The sealing portion 133s is a projection formed to surround the first inner hole 132a in a view in the thickness direction DT. The sealing portion 133s is connected to the second header 133b, which protrudes from the surface of the first header 133a to the same height as the wall portion 134a (described later) separating the adjacent second recess 134. The second header 133b connects the second inner hole 132b and the second recess 134, and diverts a portion of the second refrigerant flowing through the second communication passage 162b (described later) to the second recess 134. The surface of the second header 133b is flush with the bottom portion 134b of the second recess 134. In a view in the thickness direction DT (plan view of the second heat transfer plate 130), the second header 133b does not overlap with the second outer hole 131b, but overlaps with the second inner hole 132b. More specifically, in a view in the thickness direction DT, the second header 133b is a rectangular region enclosed by a boundary 130b extending in the width direction DW between the second outer hole 131b and the second inner hole 132b, both end edges 130es in the width direction DW, and the lower ends of the multiple second recesses 134.

[0093] The second recess 134 is a groove through which the second refrigerant, which has been diverted from the header 133, flows. The second recess 134 is a linear groove that extends along the longitudinal direction DL without branching. Multiple second recesses 134 are formed at predetermined intervals along the width direction DW (although not limited to this, in this embodiment there are approximately 130). Adjacent second recesses 134 are separated by a wall portion 134a. One end of the second recess 134 is in contact with the first header 133a, and the other end is in contact with the second header 133b.

[0094] (2-2-4) First end frame 140 and second end frame 150 The first end frame 140 is a plate-shaped member having first flow openings 141a and 141b and second flow openings 142a and 142b.

[0095] The first flow ports 141a and 141b are through holes formed in the first end frame 140. The first refrigerant flows into the first heat exchanger 100 from the first flow ports 141a and 141b. The first flow port 141a is positioned to communicate with the first inner holes 112a, 122a, and 132a. The first flow port 141b is positioned to communicate with the second outer holes 111b, 121b, and 131b.

[0096] The second flow ports 142a and 142b are through holes formed in the first end frame 140. The second refrigerant flows into the first heat exchanger 100 from the second flow ports 142a and 142b. The second flow port 142a is positioned to communicate with the first outer holes 111a, 121a, and 131a. The second flow port 142b is positioned to communicate with the second inner holes 112b, 122b, and 132b.

[0097] The second end frame 150 is a flat plate-shaped member that does not have holes formed in it.

[0098] (2-2-5) Regarding the assembly of the first heat exchanger 100, the partition wall 120 is stacked on the first heat transfer plate 110, and the opening of the first recess 114 is closed by the surface of the partition wall 120, thereby forming the first flow path 210. As a result, the first flow path 210 causes the first refrigerant that has flowed through the first communication passage 161 (described later) to flow along the surface of the first heat transfer plate 110.

[0099] The partition wall 120 is stacked on the second heat transfer plate 130, and the opening of the second recess 134 is closed by the surface of the partition wall 120, thereby forming the second flow path 220. As a result, the second flow path 220 causes the second refrigerant that has flowed through the second communication passage 162 (described later) to flow along the surface of the second heat transfer plate 130.

[0100] The first heat transfer plate 110, the partition wall 120, and the second heat transfer plate 130 are stacked so that the first inner holes 112a, 122a, and 132a communicate with each other to form a first communication passage 161a through which the first refrigerant flows along the thickness direction DT. The second heat transfer plate 110, the partition wall 120, and the second heat transfer plate are stacked so that the second outer holes 111b, 121b, and 131b communicate with each other to form a first communication passage 161b through which the first refrigerant flows along the thickness direction DT.

[0101] The first heat transfer plate 110, the partition wall 120, and the second heat transfer plate 130 are stacked so that the second inner holes 112b, 122b, and 132b communicate with each other to form a second communication passage 162b through which the second refrigerant flows along the thickness direction DT. The first heat transfer plate 110, the partition wall 120, and the second heat transfer plate 130 are stacked so that the first outer holes 111a, 121a, and 131a communicate with each other to form a second communication passage 162a through which the second refrigerant flows along the thickness direction DT.

[0102] By stacking the first end frame 140 and the second end frame 150 on the stacked first heat transfer plate 110, partition wall 120, and second heat transfer plate 130, the first flow port 141a communicates with the first connecting passage 161a, and the first flow port 141b communicates with the first connecting passage 161b. By stacking the first end frame 140 and the second end frame 150 on the stacked first heat transfer plate 110, partition wall 120, and second heat transfer plate 130, the second flow port 142a communicates with the second connecting passage 162a, and the second flow port 142b communicates with the second connecting passage 162b.

[0103] The partition wall 120 is stacked on the first heat transfer plate 110, and the surface of the partition wall 120 comes into contact with the surface of the sealing portion 113s, thereby suppressing the inflow of the second refrigerant flowing through the second inner hole 112b into the first header 113a.

[0104] The partition wall 120 is stacked on the second heat transfer plate 130, and the surface of the partition wall 120 comes into contact with the surface of the sealing portion 133s, thereby suppressing the inflow of the first refrigerant flowing through the first inner hole 132a into the second header 133.

[0105] (2-3) Flow of the First and Second Refrigerants The flow of the first refrigerant during heating and cooling operations, and the flow of the second refrigerant during heating and cooling operations will be explained separately. Figure 4 is a schematic plan view showing the flow of the first and second refrigerants during heating operations. Figure 4(a) is a plan view of the first heat transfer plate 110 in the thickness direction DT view. Figure 4(b) is a plan view of the second heat transfer plate 130 in the thickness direction DT view. In each figure, the direction in which the refrigerant flows during heating operations is indicated by an arrow. In Figure 4, for convenience, only a portion of the first recess 114 and the second recess 134 are shown.

[0106] (2-3-1) Flow of the first refrigerant During heating operation, the first refrigerant, in a low-pressure gas-liquid two-phase state, flows into the first flow port 141a of the first heat exchanger 100 and flows through the first communication passage 161a. A portion of the first refrigerant flowing through the first communication passage 161a flows out from the first inner hole 112a, passes through the first header 113a, and flows into the first flow path 210 (first recess 114). The first refrigerant that has flowed into the first flow path 210 exchanges heat with the second refrigerant by flowing through the first recess 114. The first refrigerant, which has become a low-pressure gas phase state after exchanging heat with the second refrigerant, flows through the second header 113b and into the second outer hole 111b, and then flows through the first communication passage 161b. The first refrigerant flowing through the first communication passage 161b flows out of the first heat exchanger 100 through the first flow port 141b (see arrow A in Figure 3).

[0107] During cooling operation, the first refrigerant flows in the opposite direction to that during heating operation. Specifically, the first refrigerant, in a high-pressure gaseous phase state, flows into the first flow port 141b of the first heat exchanger 100 and then flows through the first communication passage 161b. A portion of the first refrigerant flowing through the first communication passage 161b flows out through the second outer hole 111b, passes through the second header 113b, and flows into the first flow path 210 (first recess 114). The first refrigerant that has flowed into the first flow path 210 exchanges heat with the second refrigerant by flowing through the first recess 114. The first refrigerant, which has become a high-pressure liquid phase state after exchanging heat with the second refrigerant, flows through the first header 113a and then into the first inner hole 112a, and then flows through the first communication passage 161a. The first refrigerant flowing through the first communication passage 161a flows out of the first heat exchanger 100 through the first flow port 141a.

[0108] (2-3-2) Flow of the second refrigerant During heating operation, the second refrigerant, in a high-pressure gaseous phase state, flows into the second flow port 142b of the first heat exchanger 100 and flows through the second communication passage 162b (see arrow A in Figure 3). A portion of the second refrigerant flowing through the second communication passage 162b flows out from the second inner hole 132b, passes through the second header 133b, and flows into the second flow path 220 (second recess 134). The second refrigerant that has flowed into the second flow path 220 exchanges heat with the first refrigerant by flowing through the second recess 134. The second refrigerant, which has become a high-pressure liquid phase state after exchanging heat with the first refrigerant, flows through the first header 133a and into the first outer hole 131a, and then flows through the second communication passage 162a. The second refrigerant flowing through the second communication passage 162a flows out of the first heat exchanger 100 through the second flow port 142a.

[0109] During cooling operation, the first refrigerant flows in the opposite direction to that during heating operation. Specifically, the second refrigerant, in a low-pressure gas-liquid two-phase state, flows into the second flow port 142a of the first heat exchanger 100 and flows through the second communication passage 162a. A portion of the second refrigerant flowing through the second communication passage 162a flows out from the first outer hole 131a, passes through the first header 133a, and flows into the second flow path 220 (second recess 134). The second refrigerant that flows into the second flow path 220 exchanges heat with the first refrigerant by flowing through the second recess 134. The second refrigerant, which has become a low-pressure gas phase state after exchanging heat with the first refrigerant, passes through the second header 133b and flows into the second inner hole 132b, then flows through the second communication passage 162b. The second refrigerant flowing through the second communication passage 162b flows out of the first heat exchanger 100 through the second flow port 142b.

[0110] (3) Features (3-1) The first heat exchanger 100 is a heat exchanger in which a plurality of plates are stacked in the thickness direction DT (first direction). The first heat exchanger 100 comprises first communication passages 161a, 161b, second communication passages 162a, 162b, first flow path 210, and second flow path 220.

[0111] The first connecting passages 161a and 161b allow the first refrigerant (first fluid) to flow along the thickness direction DT. The second connecting passages 162a and 162b allow the second refrigerant (second fluid) to flow along the thickness direction DT.

[0112] The first flow path 210 allows the first refrigerant to flow along the surface of the first heat transfer plate 110 (first plate), which is included in a plurality of plates. The second flow path 220 allows the second refrigerant to flow along the surface of the second heat transfer plate 130 (second plate), which is included in a plurality of plates.

[0113] The first heat transfer plate 110 has a first recess 114, a first outer hole 111a and a second outer hole 111b, and a first inner hole 112a and a second inner hole 112b. The second heat transfer plate 130 has a second recess 134, a first outer hole 131a and a second outer hole 131b, and a first inner hole 132a and a second inner hole 132b.

[0114] The first outer hole 111a and the second outer hole 111b are formed so as to sandwich the first recess 114 when viewed in the thickness direction DT. The first outer hole 131a and the second outer hole 131b are formed so as to sandwich the second recess 134 when viewed in the thickness direction DT.

[0115] The first inner hole 112a is formed between the first outer hole 111a and the first recess 114 in a view in the thickness direction DT. The second inner hole 112b is formed between the second outer hole 111b and the first recess 114 in a view in the thickness direction DT. The first inner hole 132a is formed between the first outer hole 131a and the second recess 134 in a view in the thickness direction DT. The second inner hole 132b is formed between the second outer hole 131b and the second recess 134 in a view in the thickness direction DT.

[0116] The first recess 114 of the first heat transfer plate 110 is closed by an adjacent stacked partition wall 120 (another plate included in the multiple plates) to form a first flow path 210. The second recess 134 of the second heat transfer plate 130 is closed by an adjacent stacked partition wall 120 to form a second flow path 220.

[0117] The first inner holes 112a and 132a constitute a part of the first connecting passage 161a. The second outer holes 111b and 131b constitute a part of the first connecting passage 161b. The first outer holes 111a and 131a constitute a part of the second connecting passage 162a. The second inner holes 112b and 132b constitute a part of the second connecting passage 162b.

[0118] The first outer hole 111a, the second outer hole 111b, the first inner hole 112a, and the second inner hole 112b are formed on the same straight line when viewed in the thickness direction DT. The first outer hole 131a, the second outer hole 131b, the first inner hole 132a, and the second inner hole 132b are formed on the same straight line when viewed in the thickness direction DT.

[0119] To explain the features of the first heat exchanger 100, we will first describe a conventional plate heat exchanger (not shown) comprising a first heat transfer plate 510 and a second heat transfer plate 530. Figure 5 is a schematic plan view showing the flow of refrigerant in a conventional heat exchanger. In a heat exchanger comprising a first heat transfer plate 510 and a second heat transfer plate 530, the first refrigerant (heat transfer medium) flows through a first connecting passage composed of inner holes 512a, 512b of the first heat transfer plate 510 and inner holes 532a, 532b of the second heat transfer plate 530. The second refrigerant flows through a second connecting passage composed of outer holes 511a, 511b of the first heat transfer plate 510 and outer holes 531a, 531b of the second heat transfer plate 530.

[0120] In the case of a conventional heat exchanger, in the second heat transfer plate 520, the second refrigerant flowing out from the outer hole 531a comes into contact with the inner hole 532 before reaching the recess 534, and therefore cannot flow linearly toward the outer hole 531a. For this reason, in the second heat transfer plate 530, the flow rate of the second refrigerant in the center of the width direction DW of the recess 534 tends to be lower than in other parts (see Figure 5(b)). In other words, in the second heat transfer plate 530, the flow rate of the second refrigerant tends to be lower than in other parts in the outer width direction DW of the recess 534, as indicated by the hatching.

[0121] In contrast, in the first heat transfer plate 510, the first refrigerant flowing out from one inner hole 512 flows linearly toward the other outer hole 531 without coming into contact with the outer hole 511. For this reason, in the first heat transfer plate 510, the flow rate of the first refrigerant tends to be lower in the center of the width direction DW of the recess 514 shown by the hatching compared to other parts (see Figure 5(a)).

[0122] Thus, in conventional heat exchangers, the difference in the paths through which the refrigerant flows in the recesses 514 and 534 causes a flow rate bias (flow deviation). As a result, in the view along the thickness direction DT, the overlapping area between the region where the first refrigerant flows most and the region where the second refrigerant flows most is small, resulting in the problem that sufficient heat exchange efficiency cannot be ensured.

[0123] In the first heat transfer plate 110 of the first heat exchanger 100, the first inner hole 112a forms part of the first communication passage 161a, and the second outer hole 111b forms part of the first communication passage 161b. Therefore, the first refrigerant flows between the first inner hole 112a and the second outer hole 111b. In this case, the first refrigerant cannot flow in a straight line because it comes into contact with the second inner hole 112b (see Figure 4(a)).

[0124] Furthermore, in the second heat transfer plate 130 of the first heat exchanger 100, the second inner hole 132b constitutes part of the second communication passage 162b, and the first outer hole 131a constitutes part of the second communication passage 162a. Therefore, the second refrigerant flows between the second inner hole 132b and the first outer hole 131a. In this case, the second refrigerant cannot flow in a straight line because it comes into contact with the first inner hole 132a (see Figure 4(b)).

[0125] Thus, in the first heat exchanger 100, neither the first refrigerant nor the second refrigerant can flow in a straight line. Therefore, the flow rate of the refrigerant tends to be higher in the outer width direction DW of the first recess 114 and the second recess 134 (flow paths 210 and 220) shown by hatching compared to other parts. For this reason, in the thickness direction DT view, the region where the first refrigerant flows in large quantities and the region where the second refrigerant flows in large quantities can overlap almost entirely. Consequently, with the first heat exchanger 100, the region where the first refrigerant flows and the region where the second refrigerant flows tend to overlap, resulting in improved heat exchange efficiency compared to conventional designs.

[0126] (3-2) The first refrigerant that flows out from the first inner hole 112a of the first heat transfer plate 110 flows through the first flow path 210 and then flows into the second outer hole 111b.

[0127] The first heat exchanger 100 suppresses the deterioration of heat exchange efficiency caused by uneven flow of the refrigerant.

[0128] (3-3) The first refrigerant flowing out from the first inner hole 112a of the first heat transfer plate 110 is in a gas-liquid two-phase state.

[0129] The first heat exchanger 100 does not have inner holes that come into contact with the first refrigerant before it flows out of the first inner hole 112a and into the first recess 114. Therefore, the first heat exchanger 100 suppresses the occurrence of flow deviation caused by the first refrigerant flowing out of the first inner hole 112a coming into contact with the inner holes.

[0130] (3-4) The area of ​​the second outer hole 111b of the first heat transfer plate 110 is larger than the area of ​​the second inner hole 112b.

[0131] According to the first heat exchanger 100, the first refrigerant that flows out from the first inner hole 112a and comes into contact with the second inner hole 112b (in other words, flows around the second inner hole 112b) can easily flow into the second outer hole 111b.

[0132] (3-5) The first refrigerant is propane.

[0133] (3-6) The refrigeration system 1 is equipped with a first heat exchanger 100.

[0134] <Second Embodiment> (1) Refrigeration System 2 Figure 6 is a configuration diagram showing a refrigeration system 2 according to the second embodiment of the present disclosure. The following description will focus on the differences between refrigeration system 1 and refrigeration system 2. Features that are the same or corresponding in refrigeration system 1 and refrigeration system 2 are given the same reference numerals and their description is omitted. For convenience, only the area around the first heat exchanger 100 is shown in Figure 6.

[0135] The difference between refrigeration system 1 and refrigeration system 2 lies in the direction in which the refrigerant flows through the first heat exchanger 100 and the vertical direction of the first heat exchanger 100. Specifically, in the first refrigerant circuit 10 of refrigeration system 2, the fourth port 12d of the four-way switching valve 12 is connected to the first flow port 141a of the first heat exchanger 100. One end of the expansion valve 13 is connected to the first flow port 141b of the first heat exchanger 100. In the second refrigerant circuit 20 of refrigeration system 2, the second port 22b of the four-way switching valve 22 is connected to the second flow port 142a of the first heat exchanger 100. One end of the expansion valve 13 is connected to the second flow port 142b of the first heat exchanger 100.

[0136] Furthermore, in the refrigeration unit 2, the first heat exchanger 100 is positioned so that its orientation is reversed compared to the orientation shown in Figure 2. Specifically, in the first heat exchanger 100 of the refrigeration unit 2, the first flow port 141b and the second flow port 142b are positioned below the first flow port 141a and the second flow port 142a.

[0137] As a result, during heating operation, the second refrigerant, which has become a high-pressure gas phase in the compressor 21, passes through the four-way switching valve 22 in the order of the first port 22a and then the second port 22b, and reaches the second flow path 220 from the second flow port 142a of the first heat exchanger 100. In addition, the first refrigerant, which has become a low-pressure gas-liquid two-phase state in the expansion valve 13, passes through the first flow port 141b of the first heat exchanger 100, and then evaporates in the first flow path 210 to become the first refrigerant in a low-pressure gas phase state.

[0138] During cooling operation, the second refrigerant, which has become a low-pressure gas-liquid two-phase state in the expansion valve 23, passes through the second flow port 142b of the first heat exchanger 100, and then evaporates in the second flow path 220 to become a second refrigerant in a low-pressure gas phase state. The first refrigerant, which has become a high-pressure gas phase state in the compressor 11, passes through the four-way switching valve 12 in the order of the first port 12a and then the fourth port 12d, and reaches the first flow path 210 from the first flow port 141a of the first heat exchanger 100.

[0139] (2) First heat exchanger 100 (2-1) Flow of the first and second refrigerants Figure 7 is a schematic plan view showing the flow of the first and second refrigerants during heating operation. Figure 7(a) is a plan view of the first heat transfer plate 110 in the thickness direction DT. Figure 7(b) is a plan view of the second heat transfer plate 130 in the thickness direction DT. In each figure, the direction in which the refrigerant flows during heating operation is indicated by an arrow. In Figure 7, for convenience, only a portion of the first recess 114 and the second recess 134 are shown.

[0140] (2-1-1) Flow of the first refrigerant During heating operation, the first refrigerant, in a low-pressure gas-liquid two-phase state, flows into the first flow port 141b of the first heat exchanger 100 and flows through the first communication passage 161b. A portion of the first refrigerant flowing through the first communication passage 161b flows out from the second outer hole 111b, passes through the second header 113b, and flows into the first flow path 210 (first recess 114). The first refrigerant that has flowed into the first flow path 210 flows through the first recess 114 and becomes a low-pressure gas phase state, then passes through the first header 113a and flows into the first inner hole 112a, and then flows through the first communication passage 161a. The first refrigerant flowing through the first communication passage 161a flows out from the first heat exchanger 100 through the first flow port 141a.

[0141] During cooling operation, the first refrigerant flows in the opposite direction to that during heating operation. Specifically, the first refrigerant, in a high-pressure gaseous phase state, flows into the first flow port 141a of the first heat exchanger 100 and then flows through the first communication passage 161a. A portion of the first refrigerant flowing through the first communication passage 161a flows out from the first inner hole 112a, passes through the first header 113a, and flows into the first flow path 210 (first recess 114). The first refrigerant that has flowed into the first flow path 210 flows through the first recess 114 and becomes a high-pressure liquid phase state, then passes through the second header 113b and flows into the second outer hole 111b, and then flows through the first communication passage 161b. The first refrigerant flowing through the first communication passage 161b flows out of the first heat exchanger 100 through the first flow port 141b.

[0142] (2-1-2) Flow of the second refrigerant During heating operation, the second refrigerant, in a high-pressure gaseous phase state, flows into the second flow port 142a of the first heat exchanger 100 and flows through the second communication passage 162a. A portion of the second refrigerant flowing through the second communication passage 162a flows out from the first outer hole 131a, passes through the first header 133a, and flows into the second flow path 220 (second recess 134). The second refrigerant that has flowed into the second flow path 220 flows through the second recess 134 and becomes a high-pressure liquid phase state, then passes through the second header 133b and flows into the second inner hole 132b, and then flows through the second communication passage 162b. The second refrigerant flowing through the second communication passage 162b flows out of the first heat exchanger 100 through the second flow port 142b.

[0143] During cooling operation, the first refrigerant flows in the opposite direction to that during heating operation. Specifically, the second refrigerant, in a low-pressure gas-liquid two-phase state, flows into the second flow port 142b of the first heat exchanger 100 and then flows through the second communication passage 162b. A portion of the second refrigerant flowing through the second communication passage 162b flows out through the second inner hole 132b, passes through the second header 133b, and flows into the second flow path 220 (second recess 134). The second refrigerant that has flowed into the second flow path 220 flows through the second recess 134 and becomes a low-pressure gas phase state, then passes through the first header 133a and flows into the first outer hole 131a, and then flows through the second communication passage 162a. The second refrigerant flowing through the second communication passage 162a flows out of the first heat exchanger 100 through the second flow port 142a.

[0144] (3) Features (3-1) The first refrigerant that flows out from the second outer hole 111b of the first heat transfer plate 110 flows through the first flow path 210 and then flows into the first inner hole 112a.

[0145] In the first heat exchanger 100 used in the refrigeration system 2, neither the first refrigerant nor the second refrigerant can flow in a straight line. Therefore, the refrigerant flow rate tends to be higher in the outer width direction DW of the first recess 114 and second recess 134 (flow paths 210 and 220) shown by hatching in Figure 7 compared to other parts. For this reason, the region where the first refrigerant flows more and the region where the second refrigerant flows more can overlap almost entirely in the thickness direction DT view. Consequently, the deterioration of heat exchange efficiency caused by uneven flow of refrigerant can also be suppressed by the first heat exchanger 100 used in the refrigeration system 2.

[0146] (3-2) The first refrigerant flowing out of the first flow path 210 is in a gaseous state.

[0147] The first heat exchanger 100 does not have an inner hole that comes into contact with the first refrigerant flowing out of the first flow path 210 and before flowing into the first inner hole 112a. Therefore, the distance from the first flow path 210 to the first inner hole 112a can be shortened, and pressure loss to the first refrigerant in the gas phase state is suppressed.

[0148] <Conclusion> The embodiments of this disclosure have been described above, but it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of this disclosure as described in the claims.

[0149] 1, 2: Refrigeration device 100: First heat exchanger (heat exchanger) 110: First heat transfer plate (first plate) 130: Second heat transfer plate (second plate) 111a, 131a: First outer hole 111b, 131b: Second outer hole 112a, 132a: First inner hole 112b, 132b: Second inner hole 114, 134: Recess 161: First connecting passage 162: Second connecting passage 210: First flow path 220: Second flow path DT: Thickness direction (first direction) L: Straight line

[0150] Japanese Patent Publication No. 2023-51241

Claims

1. A heat exchanger (100) in which a plurality of plates are stacked in a first direction (DT), comprising: a first communication passage (161) through which a first fluid flows along the first direction; a second communication passage (162) through which a second fluid flows along the first direction; a first flow path (210) through which the first fluid flows along the surface of a first plate (110) included in the plurality of plates; and a second flow path (220) through which the second fluid flows along the surface of a second plate (130) included in the plurality of plates, wherein the first plate and the second plate have recesses (114, 134) and first outer holes (111a, 131a) and second outer holes (111b, 131b) formed so as to sandwich the recess in a first view, A heat exchanger having, in the first view, first inner holes (112a, 132a) formed between the first outer hole and the recess and second inner holes (112b, 132b) formed between the second outer hole and the recess, wherein the recess of the first plate is closed by other plates included in the plurality of adjacently stacked plates to form the first flow path, the recess of the second plate is closed by other plates included in the plurality of adjacently stacked plates to form the second flow path, the first inner hole and the second outer hole constitute a part of the first communication passage, the second inner hole and the first outer hole constitute a part of the second communication passage, and the first outer hole, the second outer hole, the first inner hole, and the second inner hole are formed on the same straight line (L) in the first view.

2. The heat exchanger according to claim 1, wherein the first fluid that flows out from the first inner hole of the first plate flows through the first flow path and then flows into the second outer hole of the first plate.

3. The heat exchanger according to claim 1 or 2, wherein the first fluid flowing out from the first inner hole of the first plate is in a gas-liquid two-phase state.

4. The heat exchanger according to any one of claims 1 to 3, wherein the area of ​​the second outer hole is larger than the area of ​​the second inner hole.

5. The heat exchanger according to claim 1, wherein the first fluid that flows out from the second outer hole of the first plate flows through the first flow path and then flows into the first inner hole of the first plate.

6. The heat exchanger according to claim 5, wherein the first fluid flowing out of the first channel of the first plate is in a gaseous state.

7. The heat exchanger according to any one of claims 1 to 5, wherein the first fluid is propane.

8. A refrigeration apparatus (1, 2) comprising a heat exchanger according to any one of claims 1 to 7.

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