Heat exchanger, and refrigeration device

Abstract

Provided is a heat exchanger capable of suppressing deviations in the flow rate of a refrigerant flowing into a flow passage functioning as a heat transfer region. A first header of a heat exchanger has a plurality of first protrusions formed therein. The first header is formed such that a first communication passage and a recessed portion communicate with each other and such that a second communication passage and the recessed portion do not communicate with each other. In the first header, the density of the first protrusions formed in a first region is lower than the density of the first protrusions formed in a second region. The first region is the region between two first straight lines in a plan view of a first plate. The first straight lines pass through both ends of a second through-hole in a third direction orthogonal to a second direction in which a first through-hole and the second through-hole are aligned, and the first straight lines extend in the second direction. The second region is a region excluding the first region.

Description

Heat exchanger, refrigeration device

[0001] It relates to a heat exchanger and a refrigeration device.

[0002] Patent Document 1 (Japanese Patent Application Laid-Open No. 2024-012151) discloses a plate heat exchanger. The plate of the plate heat exchanger disclosed in Patent Document 1 has a heat transfer region, two flow ports, two through holes, and two headers formed therein. The first fluid, which is one of the heat media, flows in from one of the flow ports and flows through the heat transfer region via the header. The second fluid, which is the other heat media, passes through the through holes. The header is formed so as to surround the flow port and the through hole, and communicates the flow port with the heat transfer region. The header has protrusions formed on its surface for the purpose of ensuring pressure resistance performance. The through holes are formed between the heat transfer region and the flow port.

[0003] In the plate heat exchanger disclosed in Patent Document 1, a part of the flow of the first fluid flowing from the flow port toward the heat transfer region is obstructed by the through hole. Therefore, among the heat transfer regions, the amount of the first fluid located downstream of the through hole is less than the flow rate at other positions. As a result, a deviation in the flow rate occurs in the flow path functioning as the heat transfer region, and ensuring the heat exchange efficiency may be hindered.

[0004] An object of the present disclosure is to provide a heat exchanger capable of suppressing a deviation in the flow rate of the refrigerant flowing into the flow path functioning as the heat transfer region.

[0005] The heat exchanger according to the first aspect is a plate heat exchanger in which a plurality of plates are laminated in the first direction. The heat exchanger includes a first communication path, a second communication path, a first flow path, and a second flow path.

[0006] The first communication path allows the first fluid to flow along the first direction. The second communication path allows the second fluid to flow along the first direction. The first flow path allows the first fluid flowing through the first communication path to flow along the surface of the first plate included in the plurality of plates. The second flow path allows the second fluid flowing through the second communication path to flow along the surface of the second plate included in the plurality of plates.

[0007] The first plate has a recess, two first through holes, and two second through holes. The second plate has a recess, two first through holes, and two second through holes.

[0008] The recess is closed by other plates included in the multiple adjacent stacked plates to form a first or second channel. The first through-hole constitutes part of the first connecting passage and is formed so as to sandwich the recess in a plan view of the multiple plates. The second through-hole constitutes part of the second connecting passage and is formed between the first through-hole and the recess in a plan view of the multiple plates.

[0009] The first plate has a first header formed to surround the first through-hole and the second through-hole in a plan view of the first plate.

[0010] The first header has multiple first protrusions formed on it. The first header is formed to connect the first connecting passage and the recess, but not to connect the second connecting passage and the recess. The density of first protrusions formed in the first region of the first header is less than the density of first protrusions formed in the second region. The first region is the region between two first straight lines in a plan view of the first plate. The first straight line extends in the second direction through both ends of the second through hole in a third direction perpendicular to the second direction in which the first and second through holes are aligned. The second region is the region excluding the first region.

[0011] The first fluid, which flows out from the first through-hole and into the first header, has its flow controlled by the first protrusions before it enters the first flow path. Specifically, in the first header, the density of the first protrusions formed in the first region is smaller than the density of the first protrusions formed in the second region, so the smooth flow of the first fluid is suppressed by the first protrusions. As a result, more of the first fluid flows into the first region located on the recessed side of the second through-hole than into the second region. This allows the heat exchanger to suppress the uneven flow rate of the first fluid flowing into the first flow path, which functions as a heat transfer region.

[0012] The heat exchanger in the second view is the heat exchanger in the first view, wherein the average size of the first plate of the first protrusion formed in the first region in a plan view may differ from the average size of the first plate of the first protrusion formed in the second region in a plan view.

[0013] The heat exchanger in the third view is the heat exchanger in the first view, wherein the number of first protrusions per unit area formed in the first region may differ from the number of first protrusions per unit area formed in the second region.

[0014] The heat exchanger of the fourth aspect is any of the heat exchangers of the first, second, or third aspects, wherein, in a plan view of the first plate, the density of first protrusions formed in the first region between the second straight line extending in a third direction through the center of the second through-hole and the edge of the recess facing the second through-hole may be smaller than the density of first protrusions formed in the second region between the second straight line and the edge of the recess facing the second through-hole.

[0015] This feature facilitates the inflow of the first fluid from the second region to the first region. As a result, this heat exchanger can further suppress the uneven flow rate of the first fluid flowing into the first flow path, which functions as a heat transfer region.

[0016] The heat exchanger of the fifth aspect is the heat exchanger of the fourth aspect, wherein, in a plan view of the first plate, the density of first protrusions formed in the first region between the third straight line extending in the third direction through the center of the first through hole and the edge of the recess facing the second through hole may be smaller than the density of first protrusions formed in the second region between the third straight line and the edge of the recess facing the second through hole.

[0017] This feature facilitates the inflow of the first fluid from the second region to the first region. As a result, this heat exchanger can further suppress the uneven flow rate of the first fluid flowing into the first flow path, which functions as a heat transfer region.

[0018] The heat exchanger of the sixth aspect is the heat exchanger of the fifth aspect, wherein, in a plan view of the first plate, the density of first protrusions formed in the second region between the third straight line and the edge of the first header facing the first through hole may be smaller than the density of first protrusions formed in the second region between the third straight line and the edge of the recess facing the second through hole.

[0019] The heat exchanger of the seventh aspect is any of the heat exchangers of the first to sixth aspects, wherein the first plate may further have a second header formed such that, in a plan view of the first plate, it sandwiches a recess together with the first header and surrounds a first through-hole and a second through-hole. The second header may have a plurality of second protrusions formed thereon. The second header may be formed to communicate the first communication passage and the recess, but not to communicate the second communication passage and the recess. In a plan view of the first plate, the second header may have second protrusions formed at a constant density.

[0020] The heat exchanger of the eighth aspect is any of the heat exchangers of the first to sixth aspects, wherein the first plate may further have a second header formed such that, in a plan view of the first plate, it sandwiches a recess together with the first header and surrounds a first through hole and a second through hole. The second header may have a plurality of second protrusions formed thereon. The second header may be formed to communicate the first communication passage and the recess, but not to communicate the second communication passage and the recess. In a plan view of the first heat transfer plate, the density of second protrusions formed in the first region may be less than the density of second protrusions formed in the second region.

[0021] The heat exchanger of the ninth aspect is the heat exchanger of the eighth aspect, in which the second projection may be positioned symmetrically with respect to the first projection and the recess.

[0022] The heat exchanger of the tenth viewpoint is any of the heat exchangers of the first to ninth viewpoints, wherein the second plate may have a third header formed so as to surround the second through-hole in a plan view of the second plate. The third header may have a plurality of third protrusions formed thereon. The third header may be formed to connect the second communication passage and the recess, but not to connect the first communication passage and the recess. The density of third protrusions formed in the third region of the third header may be greater than the density of third protrusions formed in the fourth region. The third region is the region between two fourth straight lines in a plan view of the second plate. The fourth straight line extends in the fourth direction through both ends of the second through-hole in a fifth direction perpendicular to the fourth direction in which the first and second through-holes are aligned. The fourth region is the region excluding the third region.

[0023] The second fluid, which flows out from the first through-hole and into the third header, has its flow controlled by the third protrusions before it enters the second flow path. Specifically, in the third header, the density of the third protrusions formed in the third region is greater than the density of the third protrusions formed in the fourth region, so the smooth flow of the second fluid is suppressed by the third protrusions. As a result, more of the second fluid flows into the fourth region, which is the region excluding the recessed side of the first through-hole, than into the third region. This allows the heat exchanger to suppress the uneven flow rate of the second fluid flowing into the second flow path, which functions as a heat transfer region.

[0024] The heat exchanger of the eleventh aspect is the heat exchanger of the tenth aspect, wherein the second plate may further have a fourth header formed in a plan view of the second plate so as to sandwich a recess together with the third header and surround the second through hole. The fourth header may have a plurality of fourth protrusions formed thereon. The fourth header may be formed so as to connect the second communication passage and the recess, but not to connect the first communication passage and the recess. In a plan view of the second plate, the fourth header may have the fourth protrusions formed at a constant density.

[0025] The heat exchanger of the twelfth aspect is the heat exchanger of the tenth aspect, wherein the second plate may further have a fourth header formed in a plan view of the second plate so as to sandwich a recess together with the third header and surround the second through hole. The fourth header may have a plurality of fourth protrusions formed thereon. The fourth header may be formed to connect the second communication passage and the recess, but not to connect the first communication passage and the recess. In a plan view of the second plate, the density of third protrusions formed in the third region 3 of the fourth header may be greater than the density of fourth protrusions formed in the fourth region.

[0026] The heat exchanger of the 13th aspect is any of the heat exchangers of the 12th aspect from the 1st aspect, and the inner diameter of the first communication passage may be larger than the inner diameter of the second communication passage.

[0027] The heat exchanger of the 14th aspect is any of the heat exchangers of the 12th aspect from the 1st aspect, and the inner diameter of the first communication passage may be smaller than the inner diameter of the second communication passage.

[0028] The heat exchanger of the 15th aspect is any of the heat exchangers of the 14th aspect from the first aspect, and the direction in which the first fluid flows through the first channel may be opposite to the direction in which the second fluid flows through the second channel in a plan view of the plurality of plates.

[0029] The heat exchanger of the 16th aspect is any of the heat exchangers of the 15th aspect from the 1st aspect, and either the first flow path or the second flow path may be formed by an inner fin and a recess.

[0030] The seventeenth refrigeration device comprises a heat exchanger according to either the first or sixth viewpoint.

[0031] Because the heat exchanger described above suppresses uneven fluid flow and performs heat exchange efficiently, this refrigeration system can achieve highly efficient operation.

[0032] This is a schematic diagram of the refrigeration device 1. 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 plan view of the first heat transfer plate 110 showing the arrangement of the protrusions 115. This is a plan view of the first heat transfer plate 110 showing the arrangement of the protrusions 115. This is a plan view of the first heat transfer plate 110 showing the arrangement of the protrusions 115. This is a plan view of the second heat transfer plate 130 showing the arrangement of the protrusions 135. This is a plan view of the second heat transfer plate 130 showing the arrangement of the protrusions 135. This is a plan view for explaining the flow rate of refrigerant in a heat transfer plate according to the prior art. This is a plan view for explaining the flow rate of the first refrigerant flowing into the first flow path in the first heat transfer plate 110. This is a plan view for explaining the flow rate of the second refrigerant flowing into the second flow path in the second heat transfer plate 130. This is a plan view of the first heat transfer plate 110 showing the arrangement of the protrusions 115 in the first heat exchanger 100 according to Modification 1. This is a plan view of the second heat transfer plate 130 showing the arrangement of the protrusions 135 in the first heat exchanger 100 according to Modification 1. This is a cross-sectional view showing the structure of the first flow path 210 and the second flow path 220 in the first heat exchanger 100 according to Modification 5. This is a cross-sectional view showing the structure of the first flow path 210 and the second flow path 220 in the first heat exchanger 100 according to Modification 6. This is a cross-sectional view showing the structure of the first flow path 210 and the second flow path 220 in the first heat exchanger 100 according to Modification 7. This is a cross-sectional view showing the structure of the first flow path 210 and the second flow path 220 in the first heat exchanger 100 according to another example of Modification 7. This is a plan view of the first heat transfer plate 110 showing another example of the protrusions 115. This is a plan view of the first heat transfer plate 110 showing another example of the protrusions 115. This is a plan view of the first heat transfer plate 110 showing another example of the protrusions 115.

[0033] <First Embodiment> (1) Overall Configuration of 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 diagram of the refrigeration system 1. 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.

[0034] 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 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.

[0035] The first refrigerant is an example of the first fluid. The second refrigerant is an example of the second fluid.

[0036] (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.

[0037] The first flow path 210 is a flow path through which the first refrigerant flows. The first flow path 210 functions as a heat transfer region where the first refrigerant flowing inside and the second refrigerant flowing through the second flow path 220 exchange heat. The first flow path 210 is provided between the first flow port 141a and the first flow port 141b.

[0038] The second flow path 220 is a flow path for the second refrigerant. The second flow path 220 functions as a heat transfer region where the second refrigerant flowing inside and the first refrigerant flowing through the first flow path 210 exchange heat. 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 passing through the second flow path 220. The detailed structure of the first heat exchanger 100 will be described later.

[0039] (1-2) Second heat exchanger 300 The second heat exchanger 300 causes heat exchange between the second refrigerant circulating in the second refrigerant circuit 20 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.

[0040] The first flow path 410 is a flow path for the second refrigerant. 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 for water. The second flow path 420 is formed between the second flow port 342a and the second flow port 342b. The second refrigerant flowing through the first flow path 410 exchanges heat with the water flowing through the second flow path 420.

[0041] (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 heat source heat exchanger 14. 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 heat source heat exchanger 14 are connected by piping, and the first refrigerant circulates inside them. In this embodiment, the first refrigerant is carbon dioxide.

[0042] 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.

[0043] 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.

[0044] The first port 12a is connected to the discharge part 11b of the compressor 11. The second port 12b is connected to the first flow port 141a of the first heat exchanger 100. The third port 12c is connected to the suction part 11a of the compressor 11. The fourth port 12d is connected to one end of the heat source heat exchanger 14.

[0045] The expansion valve 13 functions as a decompression device that adjusts the flow rate of the first refrigerant circulating in the first refrigerant circuit 10 and decompresses the first refrigerant.

[0046] One end of the expansion valve 13 is connected to the first flow port 141b of the first heat exchanger 100. The other end of the expansion valve 13 is connected to the other end of the heat source heat exchanger 14.

[0047] The heat source heat exchanger 14 effects heat exchange between the first refrigerant circulating in the first refrigerant circuit 10 and a heat source (for example, outdoor air).

[0048] (1 - 4) Second refrigerant circuit 20 In the second refrigerant circuit 20, the second refrigerant is heated or cooled. The second refrigerant circuit 20 is constituted by a compressor 21, a four-way switching valve 22, an expansion valve 23, the second flow path 220 of the first heat exchanger 100, and the first flow path 410 of the second heat exchanger 300. The compressor 21, the four-way switching valve 22, the expansion valve 23, the second flow path 220 of the first heat exchanger 100, and the first flow path 410 of the second heat exchanger 300 are connected by piping, and the second refrigerant circulates inside. In the present embodiment, the second refrigerant is propane.

[0049] The compressor 21 sucks the low-pressure second refrigerant in the second refrigerant circuit 20 from the suction part 21a, compresses it, and discharges it as a high-pressure second refrigerant from the discharge part 21b.

[0050] The four-way switching valve 22 has 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 state of the first port 22a, second port 22b, third port 22c, and fourth port 22d is different. In the first state, the first port 22a and the second port 22b are in communication, and the third port 22c and the fourth port 22d are in communication. In the second state, the first port 22a and the fourth port 22d are in communication, and the second port 22b and the third port 22c are in communication.

[0051] The first port 22a is connected to the discharge section 21b of the compressor 21. The second port 22b is connected to the first flow port 341a of the second heat exchanger 300. The third port 22c is connected to the suction section 21a of the compressor 21. The fourth port 22d is connected to the second flow port 142a of the first heat exchanger 100.

[0052] The expansion valve 23 functions as a pressure reducing device that adjusts the flow rate of the second refrigerant circulating in the second refrigerant circuit 20 and reduces the pressure of the second refrigerant.

[0053] One end of the expansion valve 23 is connected to the first flow port 341b of the second heat exchanger 200. The other end of the expansion valve 23 is connected to the second flow port 142b of the first heat exchanger 100.

[0054] (1-5) Water Circuit 30 In the water circuit 30, water that has exchanged heat with the second refrigerant circulates. The water circuit 30 consists of 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 piping, and water circulates inside them.

[0055] The water circulation pump 31 circulates water within the water circuit 30. The water circulation pump 31 draws water from the water circuit 30 through the suction port 31a and discharges it through the discharge port 31b.

[0056] The intake section 31a is connected to the second flow port 342b of the second heat exchanger 300.

[0057] The water storage tank 32 stores water that has been heated or cooled in the second heat exchanger 300, thereby heating or cooling (in other words, heating or cooling) the air in the space to be air-conditioned. The water storage tank 32 has a water intake section 32a that takes in water circulating in the water circuit 30 and a drainage section 32b that discharges the stored water.

[0058] The water intake section 32a is connected to the discharge section 31b of the water circulation pump 31. The drainage section 32b is connected to the second flow port 342a of the second heat exchanger 300.

[0059] The utilization heat exchanger 33 facilitates heat exchange between the water circulating in the water circuit 30 and the air in the space to be air-conditioned (not shown). The utilization heat exchanger 33 is positioned inside the space to be air-conditioned so that the water passing through it can exchange heat with the air in the space to be air-conditioned. One end of the utilization heat exchanger 33 is connected to the discharge section 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 in the water circuit 30 may be one, or it may be two or more, as shown in Figure 1.

[0060] (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 diagram, 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 able to send and receive control signals.

[0061] (1-7) Operation of the refrigeration unit 1 The refrigeration unit 1 performs heating operation and cooling operation.

[0062] (1-7-1) Heating Operation Heating operation is an operation in which the refrigeration unit 1 heats the water in the water circuit 30. In heating operation, the control unit 40 sets the four-way switching valves 12 and 22 to the first 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.

[0063] (1-7-1-1) First refrigerant circuit 10 The compressor 11 draws in the first refrigerant in the low-pressure gas phase from the intake port 11a and discharges it as the first refrigerant in the high-pressure gas phase from the discharge port 11b. The first refrigerant, which is in the high-pressure gas phase, 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 210 of the first heat exchanger 100 from the first flow port 141a. In the first flow path 210 of the first heat exchanger 100, the first refrigerant in the high-pressure gas phase condenses to become the first refrigerant in the high-pressure liquid phase. 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 that has flowed out of the first heat exchanger 100 reaches the expansion valve 13. The expansion valve 13, which is set to an appropriate opening degree, reduces the pressure of the first refrigerant in the high-pressure liquid phase to make it a two-phase first refrigerant in low-pressure gas-liquid. The low-pressure gas-liquid two-phase first refrigerant evaporates in the heat source heat exchanger 14 to become the low-pressure gas phase first refrigerant. At this time, the first refrigerant absorbs heat from the heat source. The low-pressure gas phase first refrigerant that flows out of the heat source heat exchanger 14 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.

[0064] (1-7-1-2) Second Refrigerant Circuit 20 The compressor 21 draws in the second refrigerant in the low-pressure gas phase from the suction port 21a and discharges it as the second refrigerant in the high-pressure gas phase from the discharge port 21b. The second refrigerant, which is in the high-pressure gas phase, passes through the four-way switching valve 22 in the order of the first port 22a and the second port 22b 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 second refrigerant in the high-pressure gas phase condenses to become the second refrigerant in the high-pressure liquid phase. At this time, the second refrigerant releases heat to the water passing through the second flow path 420. The second refrigerant in the high-pressure liquid phase that has flowed out of the second heat exchanger 300 reaches the expansion valve 23. The expansion valve 23, which is set to an appropriate opening degree, reduces the pressure of the second refrigerant in the high-pressure liquid phase to make it a two-phase second refrigerant in the low-pressure gas-liquid phase. The low-pressure gas-liquid two-phase second refrigerant passes through the second flow port 142b of the first heat exchanger 100, then evaporates in the second flow path 220 to become the low-pressure gas phase second refrigerant. At this time, the second refrigerant absorbs heat from the first refrigerant passing through the first flow path 210. The low-pressure gas phase second refrigerant that flows out of the first heat exchanger 100 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.

[0065] (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 second 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.

[0066] (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.

[0067] (1-7-2-1) First refrigerant circuit 10 The compressor 11 draws in the first refrigerant in the low-pressure gas phase from the intake port 11a and discharges it as the first refrigerant in the high-pressure gas phase from the discharge port 11b. The first refrigerant, which is in the high-pressure gas phase, passes through the four-way switching valve 12 in the order of the first port 12a and the fourth port 12d to reach the heat source heat exchanger 14. In the heat source heat exchanger 14, the first refrigerant in the high-pressure gas phase condenses to become the first refrigerant in the high-pressure liquid phase. At this time, the first refrigerant releases heat to the heat source. The first refrigerant in the high-pressure liquid phase that has flowed out of the heat source heat exchanger 14 reaches the expansion valve 13. The expansion valve 13, which is set to an appropriate opening degree, reduces the pressure of the first refrigerant in the high-pressure liquid phase to make it a two-phase first refrigerant in low-pressure gas-liquid. The low-pressure gas-liquid two-phase first refrigerant passes through the first flow port 141b of the first heat exchanger 100, then evaporates in the first flow path 210 to become the low-pressure gas phase first refrigerant. At this time, the first refrigerant absorbs heat from the second refrigerant passing through the second flow path 220. The low-pressure gas phase first refrigerant that flows out of the first heat exchanger 100 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 21 from the suction section 11a.

[0068] (1-7-2-2) Second Refrigerant Circuit 20 The compressor 21 draws in the second refrigerant in the low-pressure gas phase from the intake port 21a and discharges it as the second refrigerant in the high-pressure gas phase from the discharge port 21b. The second refrigerant, which is in the high-pressure gas phase, passes through the four-way switching valve 22 in the order of the second port 22b and the fourth port 22d and reaches the second flow path 220 of the first heat exchanger 100 from the second flow port 142a. In the second flow path 220 of the first heat exchanger 100, the second refrigerant in the high-pressure gas phase condenses to become the second refrigerant in the high-pressure liquid phase. 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 that has flowed out of the first heat exchanger 100 reaches the expansion valve 23. The expansion valve 23, which is set to an appropriate opening degree, reduces the pressure of the second refrigerant in the high-pressure liquid phase to make it a two-phase second refrigerant in low-pressure gas-liquid. The low-pressure gas-liquid two-phase second refrigerant passes through the first flow port 341b of the second heat exchanger 300, then evaporates in the first flow path 410 to become the low-pressure gas phase second refrigerant. At this time, the second refrigerant absorbs heat from the water passing through the second flow path 420. The low-pressure gas phase second refrigerant that flows out of the second heat exchanger 300 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.

[0069] (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 second 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.

[0070] (2) First heat exchanger 100 (2-1) Overall configuration The first heat exchanger 100 is a plate-type 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 upper inner holes 112, 122, 132 and the outer holes 111, 121, 131 (all described later). In Figure 3, the direction of flow of the first refrigerant and the second refrigerant during cooling operation is indicated by arrows.

[0071] 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.

[0072] The first heat transfer plate 110, the partition wall 120, and the second heat transfer plate 130 are the same in size and outer circumference. 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.

[0073] 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.

[0074] 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.

[0075] The first heat exchanger 100 is an example of a plate heat exchanger. The first heat transfer plate 110, the partition wall 120, and the second heat transfer plate 130 are examples of multiple plates. The first heat transfer plate 110 is an example of a first plate. The second heat transfer plate 130 is an example of a second plate. The thickness direction DT is an example of a first direction. The longitudinal direction DL is an example of a second and fourth direction. The width direction DW is an example of a third and fifth direction.

[0076] (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 the first flow channel 210. The first heat transfer plate 110 has two outer holes 111, two inner holes 112, two headers 113, and a recess 114.

[0077] The outer hole 111 is a through hole through which the first refrigerant flows. The outer hole 111 penetrates the first heat transfer plate 110 along the thickness direction DT. The outer hole 111 constitutes a part of the first communication passage 161 (described later) and is formed above and below the recess 114 in a plan view of the first heat transfer plate 110. The outer hole 111 is circular in a plan view of the first heat transfer plate 110. The outer hole 111 is formed between the upper edge 110eu of the first heat transfer plate 110 and the header 113, and between the lower edge 110eb of the first heat transfer plate 110 and the header 113 in a plan view of the first heat transfer plate 110.

[0078] The inner hole 112 is a through-hole through which the second refrigerant flows. The inner hole 112 penetrates the first heat transfer plate 110 along the thickness direction DT. The inner hole 112 constitutes a part of the second communication passage 162 (described later) and is formed above and below the recess 114 in a plan view of the first heat transfer plate 110. In a plan view of the first heat transfer plate 110, the inner hole 112 is circular. In this embodiment, the inner diameter of the inner hole 112 is larger than the inner diameter of the outer hole 111.

[0079] The inner hole 112 includes a sealing portion 112s. The sealing portion 112s suppresses the inflow of the second refrigerant flowing through the inner hole 112 into the header 113. The sealing portion 112s is a protruding portion formed to surround the inner hole 112 in a plan view of the first heat transfer plate 110. The sealing portion 112s protrudes from the surface of the header 113 to the same height as the wall portion 114b (described later) separating the adjacent groove 114a.

[0080] Header 113 connects the inner hole 112 and the recess 114, and diverts a portion of the first refrigerant flowing through the first communication passage 161 (described later) to the recess 114. In a plan view of the first heat transfer plate 110, the two headers 113 are positioned to sandwich the recess 114 from above and below, respectively, and are formed so as to surround the outer hole 111 and the inner hole 112. The surface of the header 113 is flush with the bottom surface of the groove 114a (described later) formed in the recess 114.

[0081] One of the two headers 113 (hereinafter referred to as the first header 113a) is a rectangular area enclosed by the upper edge 110eu of the first heat transfer plate 110, both edge 110es in the width direction DW, and the upper end of the recess 114 in a plan view of the first heat transfer plate 110. The other of the two headers 113 (hereinafter referred to as the second header 113b) is a rectangular area enclosed by the lower edge 110eb of the first heat transfer plate 110, a part of both edge 110es in the width direction DW, and the lower end of the recess 114 in a plan view of the first heat transfer plate 110. The two headers 113 are the same in shape and size. Multiple protrusions 115 are formed on the surface of the header 113 (see Figure 3). Details of the protrusions 115 will be described later.

[0082] The recess 114 is the region through which the first refrigerant, which has been diverted by the header 113, flows. The recess 114 is formed in a rectangular shape in a plan view of the first heat transfer plate 110, in the center of the longitudinal direction DL of the first heat transfer plate 110. The recess 114 is closed by other plates (in this embodiment, partition walls 120) included in a plurality of adjacent stacked plates to form the first flow path 210.

[0083] In this embodiment, a plurality of linear grooves 114a are formed in the recess 114 along the longitudinal direction DL. Multiple grooves 114a are formed at predetermined intervals along the width direction DW. Adjacent grooves 114a are separated by a wall portion 114b. One end of each groove 114a is in contact with the first header 113a, and the other end is in contact with the second header 113b.

[0084] Although not limited to these, the header 113, seal portion 112s, recess 114, groove 114a, and projection 115 are formed using etching.

[0085] The outer hole 111 is an example of a first through hole. The inner hole 112 is an example of a second through hole.

[0086] (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.

[0087] The partition wall 120 is a flat plate with two outer holes 121 and two inner holes 122 formed therein.

[0088] The outer hole 121 is a through-hole through which the first refrigerant flows. The outer hole 121 penetrates the partition wall 120 along the thickness direction DT. The outer hole 121 has the same shape and size as the outer hole 111 of the first heat transfer plate 110. Furthermore, when the partition wall 120 is stacked on the first heat transfer plate 110, the outer hole 121 is formed in a position that overlaps with the outer hole 111 of the heat transfer plate 110a.

[0089] The inner hole 122 is a through-hole through which the second refrigerant flows. The inner hole 122 penetrates the partition wall 120 along the thickness direction DT. The inner hole 122 has the same shape and size as the inner hole 112 of the heat transfer plate 110a. Furthermore, when the partition wall 120 is stacked on the first heat transfer plate 110, the inner hole 122 is formed in a position that overlaps with the inner hole 112 of the heat transfer plate 110a.

[0090] (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. The second heat transfer plate 130, together with the adjacently stacked partition wall 120, forms the second flow channel 220. The second heat transfer plate 130 has two outer holes 131, two inner holes 132, two headers 133, and a recess 134.

[0091] The outer hole 131 is a through-hole through which the first refrigerant flows. The outer hole 131 penetrates the second heat transfer plate 130 along the thickness direction DT. The outer hole 131 constitutes a part of the first communication passage 161 (described later) and is formed above and below the recess 134 in a plan view of the second heat transfer plate 130. The outer hole 131 has the same shape and size as the outer hole 111 of the first heat transfer plate 110 and the outer hole 121 of the partition wall 120. Furthermore, when the partition wall 120 is stacked on the second heat transfer plate 130, the outer hole 131 is formed in a position that overlaps with the outer hole 121 of the partition wall 120.

[0092] The inner hole 132 is a through-hole through which the second refrigerant flows. The inner hole 132 penetrates the second heat transfer plate 130 along the thickness direction DT. The inner hole 132 constitutes a part of the second communication passage 162 (described later) and is formed above and below the recess 134 in a plan view of the second heat transfer plate 130. The inner hole 132 has the same shape and size as the inner hole 112 of the first heat transfer plate 110 and the inner hole 122 of the partition wall 120. Furthermore, when the partition wall 120 is stacked on the second heat transfer plate 130, the inner hole 132 is formed in a position that overlaps with the inner hole 122 of the partition wall 120. In this embodiment, the inner diameter of the inner hole 132 is larger than the inner diameter of the outer hole 131.

[0093] Header 133 connects the outer hole 131 and the recess 134, and diverts a portion of the second refrigerant flowing through the second communication passage 162 (described later) to the recess 134. In a plan view of the second heat transfer plate 130, the two headers 133 are positioned to sandwich the recess 134 from above and below, respectively, so as not to surround the outer hole 131 but to surround the inner hole 132. The surface of header 133 is flush with the bottom surface of the groove 114a (described later) formed in the recess 134.

[0094] One of the two headers 133 (hereinafter referred to as the fourth header 133b) is a rectangular area enclosed by a boundary 130b extending in the width direction DW between the upper outer hole 131 and the inner hole 132, both end edges 130es in the width direction DW, and the upper end of the recess 114, in a plan view of the second heat transfer plate 130. The other of the two headers 133 (hereinafter referred to as the third header 133a) is a rectangular area enclosed by a boundary 130b extending in the width direction DW between the lower outer hole 131 and the inner hole 132, both end edges 130es in the width direction DW, and the lower end of the recess 134, in a plan view of the second heat transfer plate 130. The two headers 133 are the same in shape and size. The headers 133 have a plurality of protrusions 135 on their surface (see Figure 3). Details of the protrusions 135 will be described later.

[0095] The recess 134 is the region through which the second refrigerant, which has been diverted by the header 133, flows. The recess 134 is formed in a rectangular shape in a plan view of the second heat transfer plate 130, in the center of the second heat transfer plate 130 in the longitudinal direction DL. The recess 134 is closed by other plates (in this embodiment, partition walls 120) included in a plurality of adjacent stacked plates, thereby forming the second flow path 220.

[0096] In this embodiment, a plurality of linear grooves 134a are formed in the recess 134 along the longitudinal direction DL. Multiple grooves 134a are formed at predetermined intervals along the width direction DW. Adjacent grooves 134a are separated by a wall portion 134b. One end of each groove 134a is in contact with the first header 113a, and the other end is in contact with the fourth header 133b.

[0097] Although not limited to these, the header 133, recess 134, groove 134a, and projection 135 are formed by etching.

[0098] The outer hole 131 is an example of a first through hole. The inner hole 132 is an example of a second through hole.

[0099] (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.

[0100] 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 either the first flow port 141a or the first flow port 141b. The first flow port 141a is positioned to communicate with the outer holes 111, 121, and 131 formed above it. The first flow port 141b is positioned to communicate with the outer holes 111, 121, and 131 formed below it.

[0101] 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 inner holes 112, 122, and 132 formed above it. The second flow port 142b is positioned to communicate with the inner holes 112, 122, and 132 formed below it.

[0102] (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 groove 114a is closed on 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.

[0103] The partition wall 120 is stacked on the second heat transfer plate 130, and the opening of the groove 134a 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.

[0104] The first heat transfer plate 110, the partition wall 120, and the second heat transfer plate 130 are stacked so that the outer holes 111, 121, and 131 communicate with each other to form a first connecting passage 161 through which the first refrigerant flowing in from the first flow ports 141a and 141b flows along the thickness direction DT. In addition, the first heat transfer plate 110, the partition wall 120, and the second heat transfer plate are stacked so that the inner holes 112, 122, and 132 communicate with each other to form a second connecting passage 162 through which the second refrigerant flowing in from the second flow ports 142a and 142b flows along the thickness direction DT. In this embodiment, the inner diameter of the first connecting passage 161 is larger than the inner diameter of the second connecting passage 162.

[0105] The first end frame 140 is laminated on the stacked first heat transfer plate 110, partition wall 120, and second heat transfer plate 130, so that the first flow port 141 communicates with the first connecting passage 161 and the second flow port 142 communicates with the second connecting passage 162.

[0106] 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 133s, thereby suppressing the inflow of the second refrigerant flowing through the inner hole 132 into the header 113 (see Figure 3).

[0107] (2-3) Flow of the first and second refrigerants (2-3-1) Flow of the first refrigerant During heating operation, the first refrigerant that flows into the first flow port 141a of the first heat exchanger 100 flows through the upper first communication passage 161. A portion of the first refrigerant flowing through the first communication passage 161 passes through the first header 113a and flows into the first flow path 210 (groove 114a of the recess 114). The first refrigerant that flows into the first flow path 210 flows along the longitudinal direction DL and then flows through the second header 113b into the lower first communication passage 161. In other words, the first flow path 210 allows the first refrigerant flowing through the first communication passage 161 to flow along the surface of the first heat transfer plate 110. The first refrigerant that flows into the lower first communication passage 161 flows out of the first heat exchanger 100 through the first flow port 141b.

[0108] During cooling operation, the first refrigerant flows in the opposite direction to that during heating operation. Specifically, the first refrigerant that flows into the first flow port 141b of the first heat exchanger 100 flows through the first connecting passage 161 below. A portion of the first refrigerant flowing through the first connecting passage 161 passes through the second header 113b and flows into the first flow path 210 (groove 114a of the recess 114). The first refrigerant that flows into the first flow path 210 flows along the longitudinal direction DL and then flows through the first header 113a into the first connecting passage 161 above. The first refrigerant that flows into the first connecting passage 161 above flows out of the first heat exchanger 100 through the first flow port 141a (see arrow A in Figure 3).

[0109] (2-3-2) Flow of the second refrigerant During heating operation, the second refrigerant that flows into the second flow port 142b of the first heat exchanger 100 flows through the lower second communication passage 162. A portion of the second refrigerant flowing through the second communication passage 162 passes through the second header 113b and flows into the second flow path 220 (groove 134a of the recess 134). The second refrigerant that flows into the second flow path 220 flows along the longitudinal direction DL and then flows through the first header 113a into the upper second communication passage 162. In other words, the second flow path 220 allows the second refrigerant flowing through the second communication passage 162 to flow along the surface of the second heat transfer plate 130. The second refrigerant that flows into the upper second communication passage 162 flows out of the first heat exchanger 100 through the second flow port 142a.

[0110] During cooling operation, the second refrigerant flows in the opposite direction to the cooling operation. Specifically, the second refrigerant that flows into the second flow port 142a of the first heat exchanger 100 flows through the upper second communication passage 162 (see arrow B in Figure 3). A portion of the second refrigerant flowing through the second communication passage 162 passes through the first header 113a and flows into the second flow path 220 (groove 134a of the recess 134). The second refrigerant that flows into the second flow path 220 flows along the longitudinal direction DL and then flows through the second header 113b into the lower second communication passage 162. The second refrigerant that flows into the lower second communication passage 162 flows out of the first heat exchanger 100 through the second flow port 142b (see arrow B in Figure 3).

[0111] As explained above, the direction in which the first refrigerant flows through the first flow path 210 is opposite to the direction in which the second fluid flows through the second flow path 220, in a plan view of the first heat transfer plate 110, the partition wall 120, and the second heat transfer plate 130.

[0112] (2-4) Regarding the protrusions 115 and 135, the protrusion 115 suppresses the occurrence of flow rate bias in the first refrigerant flowing into the first flow path 210 through the header 113. The protrusion 135 suppresses the occurrence of flow rate bias in the second refrigerant flowing into the second flow path 220 through the header 133. Figures 4, 5, and 6 are plan views of the first heat transfer plate 110 showing the arrangement of the protrusions 115. Figures 7 and 8 are plan views of the second heat transfer plate 130 showing the arrangement of the protrusions 135. Figures 5, 6, and 8 are enlarged views of the upper headers 113 and 133. For convenience, the protrusions 115 and 135 are omitted in Figures 5, 6, and 8.

[0113] (2-4-1) Protrusions 115 The first heat transfer plate 110 is formed such that, in a plan view of the first heat transfer plate 110, the density of protrusions 115 formed in the first region a1 of the header 113 is different from the density of protrusions 115 formed in the second region a2 of the header 113. Specifically, in a plan view of the first heat transfer plate 110, the density of protrusions 115 formed in the first region a1 is smaller than the density of protrusions 115 formed in the second region a2.

[0114] The first region a1 is the region between the two first straight lines L1. The first straight line L1 extends in the longitudinal direction DL through both ends of the inner hole 112 in the width direction DW, which is perpendicular to the longitudinal direction DL where the outer hole 111 and the inner hole 112 are aligned. The second region a2 is the region of the header 113 excluding the first region a1 (see Figure 5). "Both ends of the inner hole 112" refers to both ends of the seal portion 112s.

[0115] In a plan view of the first heat transfer plate 110, the density of the first protrusions 115a formed in the first region a1 between the second straight line L2, which passes through the center of the inner hole 112 and extends in the width direction DW, and the edge 114e of the recess 114 facing the inner hole 112, is smaller than the density of the first protrusions 115a formed in the first portion a21 of the second region a2. The first portion a21 of the second region a2 is the region of the second region a2 between the second straight line L2, which passes through the center of the inner hole 112 and extends in the width direction DW, and the edge 114e of the recess 114 facing the inner hole 112 in the longitudinal direction DL, in a plan view of the first heat transfer plate 110 (see Figure 6).

[0116] In a plan view of the first heat transfer plate 110, the density of the first protrusions 115a formed in the first region a1 between the third straight line L3, which passes through the center of the outer hole 111 and extends in the width direction DW, and the edge 114e of the recess 114 facing the inner hole 112, is smaller than the density of the first protrusions 115a formed in the first portion a21 and the second portion a22 of the second region a2. The second portion a22 of the second region a2 is the region between the third straight line L3 and the second straight line L2 in a plan view of the first heat transfer plate 110 (see Figure 6).

[0117] In a plan view of the first heat transfer plate 110, the density of the first protrusions 115a formed in the third portion a23 of the second region a2 may be smaller than the density of the first protrusions 115a formed in the first portion a21 and the second portion a22 of the second region a2. The third portion a23 of the second region a2 is the region of the second region a2 between the third straight line L3 and the edge 113e of the header 113 facing the outer hole 111 in the longitudinal direction DL, in a plan view of the first heat transfer plate 110 (see Figure 6).

[0118] In this embodiment, the difference in the density of the protrusions 115 is achieved by the difference in the number of protrusions 115 per unit area. Specifically, in this embodiment, the size and shape of each protrusion 115 in a plan view of the first heat transfer plate 110 are the same, and the number of protrusions 115 per unit area formed in the first region a1 is less than the number of protrusions 115 per unit area formed in the second region a2.

[0119] In this embodiment, as shown in Figure 4, the projection 115 formed on the second header 113b (hereinafter referred to as the first projection 115a) is positioned symmetrically with the projection 115 formed on the first header 113a (hereinafter referred to as the second projection 115b) across the recess 114.

[0120] (2-4-2) Protrusions 135 The second heat transfer plate 130 is formed such that, in a plan view of the second heat transfer plate 130, the density of protrusions 135 formed in the third region a3 of the header 133 is different from the density of protrusions 135 formed in the fourth region a4 of the header 133. Specifically, in a plan view of the second heat transfer plate 130, the density of protrusions 135 formed in the third region a3 is greater than the density of protrusions 135 formed in the fourth region a4.

[0121] The third region a3 is the region between the two fourth lines L4. The fourth line L4 extends along the longitudinal direction DL, passing through both ends of the inner hole 132 in the width direction DW which is perpendicular to the longitudinal direction DL where the outer hole 131 and the inner hole 132 are aligned. The fourth region a4 is the region of the header 133 excluding the third region a3 (see Figure 8).

[0122] In this embodiment, the difference in the density of the protrusions 135 is achieved by the difference in the number of protrusions 135 per unit area. Specifically, in this embodiment, the size and shape of each protrusion 135 in a plan view of the second heat transfer plate 130 are the same, and the number of protrusions 135 per unit area formed in the third region a3 is less than the number of protrusions 135 per unit area formed in the fourth region a4.

[0123] In this embodiment, as shown in Figure 5, the projection 135 formed on the third header 133a (hereinafter referred to as the third projection 135a) is positioned symmetrically with the projection 135 formed on the fourth header 133b (hereinafter referred to as the fourth projection 135b) across the recess 134.

[0124] (3) Features (3-1) The first heat exchanger 100 is a plate heat exchanger in which a plurality of plates are stacked in the thickness direction DT. The first heat exchanger 100 includes a first communication passage 161, a second communication passage 162, a first flow path 210, and a second flow path 220.

[0125] The first communication passage 161 allows the first fluid to flow along the thickness direction DT. The second communication passage 162 allows the second fluid to flow along the thickness direction DT. The first flow path 210 allows the first fluid flowing through the first communication passage 161 to flow along the surface of the first heat transfer plate 110, which is included in the plurality of plates. The second flow path 220 allows the second fluid flowing through the second communication passage 162 to flow along the surface of the second heat transfer plate 130, which is included in the plurality of plates.

[0126] The first heat transfer plate 110 has a recess 114, two outer holes 111, and two inner holes 112. The second heat transfer plate 130 has a recess 134, two outer holes 131, and two inner holes 132.

[0127] The recess 114 is closed by other plates included in the multiple adjacent stacked plates to form a first flow path 210. The recess 134 is closed by other plates included in the multiple adjacent stacked plates to form a second flow path 220. The outer hole 111 constitutes part of the first connecting passage 161 and is formed to sandwich the recess 114 in a plan view of the multiple plates. The outer hole 131 constitutes part of the first connecting passage 161 and is formed to sandwich the recess 134 in a plan view of the multiple plates. The inner hole 112 constitutes part of the second connecting passage 162 and is formed between the outer hole 111 and the recess 114 in a plan view of the multiple plates. The inner hole 132 constitutes part of the second connecting passage 162 and is formed between the outer hole 131 and the recess 134 in a plan view of the multiple plates.

[0128] The first heat transfer plate 110 has a first header 113a formed to surround the outer hole 111 and the inner hole 112 in a plan view of the first heat transfer plate 110.

[0129] The first header 113a has a plurality of first protrusions 115a formed thereon. The first header 113a is formed to connect the first communication passage 161 and the recess 114, but not to connect the second communication passage 162 and the recess 114. The density of the first protrusions 115a formed in the first region a1 of the first header 113a is smaller than the density of the first protrusions 115a formed in the second region a2. The first region a1 is the region between two first straight lines L1 in a plan view of the first heat transfer plate 110. The first straight line L1 extends in the longitudinal direction DL through both ends of the inner hole 112 in the width direction DW which is perpendicular to the longitudinal direction DL where the outer hole 111 and the inner hole 112 are aligned. The second region a2 is the region excluding the first region a1. The second region a2 is the region in the width direction DW that is on the edge 113e side of the first header 113a than the inner hole 112. The second region a2 is the region between the first straight line L1 and the edge 113e of the first header 113a in the width direction DW.

[0130] Figure 9 is a plan view illustrating the flow rate of refrigerant in a conventional heat transfer plate 500. In Figure 9, the flow rate of refrigerant is indicated by the thickness of the arrows. In Figure 9, components corresponding to the first heat transfer plate 110 are given the same reference numerals. The difference between the first heat transfer plate 110 and the heat transfer plate 500 is that the first heat transfer plate 110 is equipped with a first projection 115a. As shown in Figure 9, if the first projection 115a is not provided, a portion of the refrigerant flowing out from the outer hole 111 is prevented from flowing linearly to the first flow path 210 by the inner hole 112. As a result, the flow rate of the first refrigerant on the recess 114 side of the inner hole 112 in the header 113 is less than the flow rate at other locations. As a result, an uneven flow rate of the first refrigerant occurs in the first flow path 210, which hinders the securing of heat exchange efficiency.

[0131] Figure 10 is a plan view illustrating the flow rate of the first refrigerant flowing into the first flow path in the first heat transfer plate 110. In Figure 10, the flow rate of the first refrigerant is indicated by the thickness of the arrows. The first refrigerant, which flows out from the outer hole 111 and into the first header 113a, has its flow controlled by the first protrusions 115a before it flows into the first flow path 210. Specifically, in the first header 113a, the density of the first protrusions 115a formed in the first region a1 is smaller than the density of the first protrusions 115a formed in the second region a2, so the smooth flow of the first refrigerant is suppressed by the first protrusions 115a. As a result, more of the first refrigerant flows into the first region a1, which is located on the recess 114 side of the inner hole 112, than into the second region a2. This allows the first heat exchanger 100 to suppress the uneven flow rate of the refrigerant flowing into the first flow path 210, which functions as a heat transfer region.

[0132] (3-2) The number of first protrusions 115a per unit area formed in the first region a1 may be different from the number of first protrusions 115a per unit area formed in the second region a2.

[0133] (3-3) In a plan view of the first heat transfer plate 110, the density of the first protrusions 115a formed in the first region a1 between the second straight line L2 that passes through the center of the inner hole 112 and extends in the width direction DW and the edge 114e of the recess 114 facing the inner hole 112 may be smaller than the density of the first protrusions 115a formed in the second region a2 (in other words, the first portion a21 of the second region a2) between the second straight line L2 and the edge 114e of the recess 114 facing the inner hole 112.

[0134] This feature promotes the inflow of the first refrigerant from the second region a2 to the first region a1. As a result, the first heat exchanger 100 can further suppress the uneven flow rate of the first refrigerant flowing into the first flow path 210, which functions as a heat transfer region.

[0135] (3-4) In a plan view of the first heat transfer plate 110, the density of the first protrusions 115a formed in the first region a1 between the third straight line L3 that passes through the center of the outer hole 111 and extends in the width direction DW and the edge 114e of the recess 114 facing the inner hole 112 may be smaller than the density of the first protrusions 115a formed in the second region a2 between the third straight line L3 and the edge 114e of the recess 114 facing the inner hole 112 (in other words, the first portion a21 and the second portion a22 of the second region a2).

[0136] This feature promotes the inflow of the first refrigerant from the second region a2 to the first region a1. As a result, the first heat exchanger 100 can further suppress the uneven flow rate of the first refrigerant flowing into the first flow path 210, which functions as a heat transfer region.

[0137] (3-5) In a plan view of the first heat transfer plate 110, the density of the first protrusions 115a formed in the second region a2 (in other words, the third portion a23 of the second region a2) between the third straight line L3 and the edge 113e of the first header 113a facing the outer hole 111 may be smaller than the density of the first protrusions 115a formed in the second region a2 (in other words, the first portion a21 and the second portion a22 of the second region a2) between the third straight line L3 and the edge 114e of the recess 114 facing the inner hole 112.

[0138] (3-6) The first heat transfer plate 110 may further have a second header 113b that, in a plan view of the first heat transfer plate 110, sandwiches the recess 114 together with the first header 113a and surrounds the outer hole 111 and the inner hole 112. The second header 113b may have a plurality of second protrusions 115b formed thereon. The second header 113b may be formed to connect the first communication passage 161 and the recess 114, but not to connect the second communication passage 162 and the recess 114. In a plan view of the first heat transfer plate 110, the density of second protrusions 115b formed in the first region a1 may be less than the density of second protrusions 115b formed in the second region a2.

[0139] (3-7) The second projection 115b may be positioned symmetrically with respect to the first projection 115a and the recess 114.

[0140] (3-8) The second heat transfer plate 130 may have a third header 133a formed to surround the inner hole 132 in a plan view of the second heat transfer plate 130. The third header 133a may have a plurality of third protrusions 135a formed thereon. The third header 133a may be formed to connect the second communication passage 162 and the recess 134, but not to connect the first communication passage 161 and the recess 134. The density of third protrusions 135a formed in the third region a3 of the third header 133a may be greater than the density of third protrusions 135a formed in the fourth region a4. The third region a3 is the region between the two fourth straight lines L4 in a plan view of the second heat transfer plate 130. The fourth straight line L4 extends along the longitudinal direction DL, passing through both ends of the inner hole 132 in the width direction DW which is perpendicular to the longitudinal direction DL where the outer hole 111 and the inner hole 132 are aligned. The fourth region a4 is the region excluding the third region a3.

[0141] Figure 11 is a plan view illustrating the flow rate of the second refrigerant flowing into the second flow path in the second heat transfer plate 130. In Figure 11, the flow rate of the second refrigerant is indicated by the thickness of the arrows. The second refrigerant, which flows out from the outer hole 131 and into the third header 133a, has its flow controlled by the third protrusion 135a before flowing into the second flow path 220. Specifically, in the third header 133a, the density of the third protrusion 135a formed in the third region a3 is greater than the density of the third protrusion 135a formed in the fourth region a4, so the smooth flow of the second refrigerant is suppressed by the third protrusion 135a. As a result, more of the second refrigerant flows into the fourth region a4, which is the region excluding the recess 134 side of the outer hole 131, than into the third region a3. This allows the first heat exchanger 100 to suppress the unevenness of the flow rate of the second refrigerant flowing into the second flow path 220, which functions as a heat transfer region.

[0142] (3-9) The second heat transfer plate 130 may further have a fourth header 133b formed to sandwich the recess 134 together with the third header 133a and surround the inner hole 132 in a plan view of the second heat transfer plate 130. The fourth header 133b may have a plurality of fourth protrusions 135b formed thereon. The fourth header 133b may be formed to connect the second communication passage 162 and the recess 134, but not to connect the first communication passage 161 and the recess 134. In a plan view of the second heat transfer plate 130, the density of the third protrusions 135a formed in the third region a3 of the fourth header 133b may be greater than the density of the fourth protrusions 135b formed in the fourth region a4.

[0143] (3-10) The inner diameter of the first connecting passage 161 may be larger than the inner diameter of the second connecting passage 162.

[0144] (3-11) The direction in which the first fluid flows through the first channel 210 may be opposite to the direction in which the second fluid flows through the second channel 220 in a plan view of the multiple plates.

[0145] (3-12) The refrigeration system 1 is equipped with a first heat exchanger 100.

[0146] Because the first heat exchanger 100 suppresses uneven flow rates of the refrigerant and performs heat exchange efficiently, the refrigeration system 1 can achieve highly efficient operation.

[0147] (4) Modified Examples (4-1) Modified Example 1 The difference in density of the protrusions 115 and 135 may be achieved by the difference in the average size of the protrusions 115 and 135 in a plan view of the first heat transfer plate 110 and the second heat transfer plate 130.

[0148] In the first heat exchanger 100 according to Modification 1, the number of protrusions 115 per unit area is the same, and the average size of the protrusions 115 formed in the first region a1 on the first heat transfer plate 110 in a plan view is smaller than the average size of the protrusions 115 formed in the second region a2 on the first heat transfer plate 110 in a plan view. Also, in the first heat exchanger 100 according to Modification 1, the number of protrusions 135 per unit area is the same, and the average size of the protrusions 135 formed in the third region a3 on the second heat transfer plate 130 in a plan view is larger than the average size of the protrusions 135 formed in the fourth region a4 on the second heat transfer plate 130 in a plan view.

[0149] Figure 12 is a plan view of the first heat transfer plate 110 showing the arrangement of the protrusions 115 in the first heat exchanger 100 according to Modification 1. Figure 13 is a plan view of the second heat transfer plate 130 showing the arrangement of the protrusions 135 in the first heat exchanger 100 according to Modification 1.

[0150] (4-2) Modification 2 The first projection 115a does not have to be positioned symmetrically with respect to the second projection 115b and the recess 114. Also, the third projection 135a does not have to be positioned symmetrically with respect to the fourth projection 135b and the recess 134.

[0151] (4-3) Modification 3 In the first heat exchanger 100 according to Modification 2, the second header 113b of the first heat transfer plate 110 may have second protrusions 115b formed at a constant density in a plan view of the first heat transfer plate 110. Similarly, the fourth header 133b of the second heat transfer plate 130 may have third protrusions 135a formed at a constant density in a plan view of the second heat transfer plate 130.

[0152] (4-4) Modification 4 The inner diameter of the first connecting passage 161 may be smaller than the inner diameter of the second connecting passage 162. In other words, the inner diameters of the outer holes 111, 121, and 131 may be smaller than the inner diameters of the inner holes 112, 122, and 132.

[0153] (4-5) Modification 5 Figure 14 is a cross-sectional view showing the structure of the first flow path 210 and the second flow path 220 in the first heat exchanger 100 according to Modification 5. As shown in Figure 8, in the first heat exchanger 100 according to Modification 5, the first heat transfer plate 110 and the second heat transfer plate 130 are stacked alternately with a partition wall 170 in between instead of a partition wall 120.

[0154] The difference between partition wall 120 and partition wall 170 is that partition wall 170 has grooves 171 formed on its surface. As shown in Figure 14, grooves 171 are formed so as to form a first flow path 210 opposite groove 114a when partition wall 170 is stacked on the first heat transfer plate 110. Grooves 171 are also formed so as to form a second flow path 220 opposite groove 134a when partition wall 170 is stacked on the second heat transfer plate 130.

[0155] The first flow path 210 is formed by stacking a partition wall 170 with grooves 171 formed on the first heat transfer plate 110, and closing the opening of groove 114a with groove 171. The second flow path 220 is formed by stacking a partition wall 170 on the second heat transfer plate 130, and closing the opening of groove 114a with groove 171.

[0156] While not limited to these, groove 114a is formed by etching. The cross-sectional shapes of grooves 114a, 134a, and 171 shown in Figure 14 are examples, and they may also be semicircular in shape as shown in Figure 3.

[0157] (4-6) Modification 6 Figure 15 is a cross-sectional view showing the structure of the first flow path 210 and the second flow path 220 in the first heat exchanger 100 according to Modification 6. As shown in Figure 15, in the first heat exchanger 100 according to Modification 6, the first heat transfer plate 110 further has inner fins 116. The second heat transfer plate 130 further has inner fins 136. Furthermore, the first heat transfer plate 110 and the second heat transfer plate 130 are stacked alternately with spacers 123 in between instead of partition walls 120.

[0158] The inner fins 116 and 136 are plate-shaped members with a corrugated cross-section. In a plan view, the corrugations of the inner fins 116 and 136 are formed such that the peaks of the corrugations extend along the longitudinal direction DL.

[0159] The inner fin 116 is positioned in the center of the first heat transfer plate 110 in the longitudinal direction DL, similar to the recess 114 of the first heat exchanger 100 according to the first embodiment. Furthermore, in a plan view of the first heat transfer plate 110, the outer edge of the inner fin 116 is formed in a rectangular shape.

[0160] The inner fin 136 is positioned in the center of the second heat transfer plate 130 in the longitudinal direction DL, similar to the recess 134 of the first heat exchanger 100 according to the first embodiment. Furthermore, in a plan view of the second heat transfer plate 130, the outer edge of the inner fin 136 is formed in a rectangular shape.

[0161] The spacer 123 is positioned at the edges of the first heat transfer plate 110 and the second heat transfer plate 130, forming a space in which the inner fins 116 and 136 are positioned.

[0162] In the first heat exchanger 100 according to Modification 6, the recess 114 of the first heat transfer plate 110 is composed of a plurality of valleys 116a formed in the inner fin 116. By stacking the second heat transfer plate 130 on the first heat transfer plate 110, a first flow path 210 is formed between the valleys 116a and the second heat transfer plate 130 facing the inner fin 116. Similarly, in the first heat exchanger 100 according to Modification 6, the recess 134 of the second heat transfer plate 130 is composed of a plurality of valleys 136a formed in the inner fin 136. By stacking the first heat transfer plate 110 on the second heat transfer plate 130, a second flow path 220 is formed between the valleys 136a and the first heat transfer plate 110 facing the inner fin 136.

[0163] (4-7) Modification 7 Figure 16 is a cross-sectional view showing the structure of the first flow path 210 and the second flow path 220 in the first heat exchanger 100 according to Modification 7. As shown in Figure 16, in the first heat exchanger 100 according to Modification 7, the first heat transfer plate 110 and the second heat transfer plate 130 are stacked alternately without a partition wall 120 in between. The first heat transfer plate 110 has a plurality of linear grooves 114a formed on the side opposite to the recess 114 along the longitudinal direction DL. The grooves 114a are formed to constitute the second flow path 220 when the first heat transfer plate 110 and the second heat transfer plate 130 are stacked, facing the grooves 134a of the second heat transfer plate 130. Similarly, the second heat transfer plate 130 has a plurality of linear grooves 134a formed on the side opposite to the recess 134 along the longitudinal direction DL. The groove 134a is formed to constitute the first flow path 210 when the first heat transfer plate 110 and the second heat transfer plate 130 are stacked, and is opposite the groove 114a of the first heat transfer plate 110.

[0164] Figure 17 is a cross-sectional view showing the structure of the first flow path 210 and the second flow path 220 in the first heat exchanger 100 according to another example of Modification 7. As shown in Figure 17, in the first heat exchanger 100 according to Modification 7, a partition wall 120 may be stacked between the first heat transfer plate 110 and the second heat transfer plate 130.

[0165] While not limited to these, groove 114a is formed by etching. The cross-sectional shapes of grooves 114a, 134a, and 171 shown in Figures 16 and 14 are examples, and they may also be semicircular in shape as shown in Figure 3.

[0166] (4-8) Modification 8 The fluid that the first heat exchanger 100 uses for heat exchange is not limited to refrigerants such as carbon dioxide and propane, but may also be water.

[0167] However, the first heat exchanger 100 can more effectively suppress the uneven flow rate of the refrigerant flowing into the first flow path 210 when a refrigerant is used instead of water.

[0168] Furthermore, even when a refrigerant is used, the first heat exchanger 100 can more effectively suppress the uneven flow rate of the refrigerant flowing into the first flow path 210 if a refrigerant that is in a two-phase state in the first heat exchanger 100 is used.

[0169] (4-9) Modification 9 The shape of the projections 115 and 135 in plan view is not limited to circular. Figures 18, 19, and 20 are plan views of the first heat transfer plate 110 showing other examples of projections 115. The shape of the projection 115 in plan view may be triangular (see Figure 18), quadrilateral (see Figure 19), or teardrop-shaped (see Figure 20). Although not shown, the projection 135 may have a similar shape. Also, the projections 115 and 135 may have different shapes from each other.

[0170] <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.

[0171] 1: Refrigeration device 3: Third region 4: Fourth projection 110: First heat transfer plate (first plate) 111: Outer hole (first through hole) 112: Inner hole (second through hole) 113: Header 113a: First header 113b: Second header 113e: Edge 114: Recess 114e: Edge 115: Projection 115a: First projection 115b: Second projection 116: Inner fin 116a: Valley 130: Second heat transfer plate (second plate) 131: Outer hole (first through hole) 132: Inner hole (second through hole) 133: Header 133a: Third header 133b: Fourth header 133e: Edge 134 : recess 134e : edge 135 : projection 135a : third projection 135b : fourth projection 136 : inner fin 136a : valley 161 : first connecting passage 162 : second connecting passage 210 : first flow path 220 : second flow path 410 : first flow path 420 : second flow path a1 : first region a2 : second region a21 : first part a22 : second part a23 : third part a3 : third region a4 : fourth region DT : thickness direction (first direction) DL : longitudinal direction (second direction, fourth direction) DW : width direction (third direction, fifth direction) L1 : first straight line L2 : second straight line L3 : third straight line L4 :4th straight line

[0172] Patent No. 2024-012151

Claims

1. A plate heat exchanger comprising a plurality of plates stacked in a first direction (DT), comprising: a first communication passage (161) through which a first fluid flows along the first direction (DT); a second communication passage (162) through which a second fluid flows along the first direction (DT); a first flow path (210) through which the first fluid flowing in the first communication passage (161) 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 flowing in the second communication passage (162) flows along the surface of a second plate (130) included in the plurality of plates, wherein the first plate (110) and the second plate (130) have recesses (114) that are blocked by other plates included in the plurality of adjacently stacked plates to form the first flow path (210) or the second flow path (220), The first connecting passage (161) has two first through holes (111, 131) that form part of the first connecting passage (161) and are formed so as to sandwich the recess (114) in a plan view of the plurality of plates, and the second connecting passage (162) has two second through holes (112, 132) that form part of the second connecting passage (162) and are formed between the first through holes (111, 131) and the recess (114) in a plan view of the plurality of plates, and the first plate (110) has a first header (113a) formed so as to surround the first through holes (111, 131) and the second through holes (112, 132) in a plan view of the first plate (110), and the first header (113a) has a plurality of first protrusions (115a) formed thereon A heat exchanger wherein the first communication passage (161) is formed to connect the recess (114), and the second communication passage (162) is formed not to connect the recess (114), and in a plan view of the first plate (110), the density of the plurality of first protrusions (115a) formed in a first region (a1) between two first straight lines (L1) extending in the second direction (DL) through both ends of the second through holes (112, 132) in a third direction (DW) perpendicular to the second direction (DL) in which the first through holes (111, 131) and the second through holes (112, 132) are aligned is smaller than the density of the plurality of first protrusions (115a) formed in a second region (a2), which is the region excluding the first region (a1).

2. The heat exchanger according to claim 1, wherein the average size of the first projection (115a) formed in the first region (a1) in a plan view of the first plate (110) is different from the average size of the first projection (115a) formed in the second region (a2) in a plan view of the first plate (110).

3. The heat exchanger according to claim 1, wherein the number of first protrusions (115a) per unit area formed in the first region (a1) is different from the number of first protrusions (115a) per unit area formed in the second region (a2).

4. In a plan view of the first plate (110), the density of the first projection (115a) formed in the first region (a1) between the second straight line (L2) passing through the center of the second through-hole (112, 132) and extending in the third direction (DW) and the edge (114e) of the recess (114) facing the second through-hole (112, 132) is smaller than the density of the first projection (115a) formed in the second region (a2) between the second straight line (L2) and the edge (114e) of the recess (114) facing the second through-hole (112, 132), according to any one of claims 1 to 4.

5. In a plan view of the first plate (110), the density of the first projections (115a) formed in the first region (a1) between a third straight line (L3) passing through the center of the first through holes (111, 131) and extending in the third direction (DW) and the edge (114e) of the recess (114) facing the second through holes (112, 132) is smaller than the density of the first projections (115a) formed in the second region (a2) between the third straight line (L3) and the edge (114e) of the recess (114) facing the second through holes (112, 132), according to claim 4.

6. In a plan view of the first plate (110), the density of the first projections (115a) formed in the second region (a2) between the third straight line (L3) and the edge (113e) of the first header (113) facing the first through holes (111, 131) is smaller than the density of the first projections (115a) formed in the second region (a2) between the third straight line (L3) and the edge (114e) of the recess (114) facing the second through holes (112, 132), according to claim 5.

7. The heat exchanger according to any one of claims 1 to 6, wherein the first plate (110) further has a second header (113b) formed in a plan view of the first plate (110) that sandwiches the recess together with the first header and surrounds the first through holes (111, 131) and the second through holes (112, 132), the second header (113b) having a plurality of second protrusions (115b) formed thereon, which connect the first communication passage (161) and the recess (114), and which do not connect the second communication passage (162) and the recess (114), and in a plan view of the first plate, the second protrusions (115b) are formed at a constant density.

8. The heat exchanger according to any one of claims 1 to 6, wherein the first plate (110) further has a second header (113b) formed to sandwich the recess together with the first header in a plan view of the first plate (110) and surround the first through holes (111, 131) and the second through holes (112, 132), the second header (113b) having a plurality of second protrusions (115b) formed thereon, communicating the first communication passage (161) and the recess (114), and not communicating the second communication passage (162) and the recess (114), and in a plan view of the first plate (110), the density of the second protrusions (115b) formed in the first region (a1) is smaller than the density of the second protrusions (115b) formed in the second region (a2).

9. The heat exchanger according to claim 8, wherein the second projection (115b) is positioned symmetrically with respect to the first projection (115a) and the recess (114).

10. The second plate (130) has a third header (133a) formed to surround the second through holes (112, 132) in a plan view of the second plate (130), and the third header (133a) has a plurality of third projections (135a) formed thereon, which connect the second passage (162) and the recess (134), and which are formed not to connect the first passage (161) and the recess (134). A heat exchanger according to any one of claims 1 to 9, wherein, in a plan view of the second plate (130), the density of the third protrusions (135a) formed in the third region (3) between two fourth straight lines (L4) extending in the fourth direction (DL) through both ends of the second through holes (112, 132) in the fifth direction (DW) perpendicular to the fourth direction (DL) in which the first through hole (131) and the second through hole (132) are aligned is greater than the density of the plurality of third protrusions (135a) formed in the fourth region (a4), which is the region excluding the third region (3).

11. The heat exchanger according to claim 10, wherein the second plate (130) further has a fourth header (133b) formed in a plan view of the second plate (130) to sandwich the recess (134) together with the third header (133a) and surround the second through hole (132), the fourth header (133b) has a plurality of fourth protrusions (135b) formed thereon, which connect the second communication passage (162) and the recess (134) and which do not connect the first communication passage (161) and the recess (114), and in a plan view of the second plate (130) the fourth protrusions (135b) are formed at a constant density.

12. The heat exchanger according to claim 10, wherein the second plate (130) further has a fourth header (133b) formed in a plan view of the second plate (130) so as to sandwich the recess (134) together with the third header (133a) and surround the second through hole (132), the fourth header (133b) has a plurality of fourth protrusions (135b) formed thereon, which connect the second communication passage (162) and the recess (134), and which do not connect the first communication passage (161) and the recess (134), and in a plan view of the second plate (130), the density of the third protrusions (135a) formed in the third region (a3) ​​is greater than the density of the fourth protrusions (135b) formed in the fourth region (a4).

13. The heat exchanger according to any one of claims 1 to 12, wherein the inner diameter of the first communication passage (161) is larger than the inner diameter of the second communication passage (162).

14. The heat exchanger according to any one of claims 1 to 12, wherein the inner diameter of the first communication passage (161) is smaller than the inner diameter of the second communication passage (162).

15. The heat exchanger according to any one of claims 1 to 14, wherein the direction in which the first fluid flows through the first channel (210) is opposite to the direction in which the second fluid flows through the second channel (220) in a plan view of the plurality of plates.

16. The heat exchanger according to any one of claims 1 to 15, wherein the first plate (110) further has an inner fin (116), and the recess (114) is a valley (116a) of the inner fin (116).

17. A refrigeration apparatus (1) comprising a heat exchanger according to any one of claims 1 to 16.

Images