Heat exchanger

Abstract

Provided is a heat exchanger that suppresses refrigerant leakage when water freezes and expands in volume. A heat exchanger (100) performs heat exchange between water and a refrigerant. A heat exchanger (100) is provided with a first flow path (111) through which water flows and a second flow path (121) through which a refrigerant flows. The member forming the first flow path (111) or the portion where the members forming the first flow path (111) are joined to each other functions as a fragile portion (190) having a lower strength than other portions. In a heat exchanger (100), when water freezes and expands in volume, members forming a first flow path (111) or portions where the members forming the first flow path (111) are joined, which function as fragile portions (190), break earlier than other portions. Therefore, according to the heat exchanger (100), when water freezes and the volume expands, the condition of refrigerant leakage caused by cracking of the parts or the joint parts forming the second flow path (121) can be inhibited.

Description

Technical Field

[0001] The present invention relates to heat exchangers. Background Art

[0002] A plate heat exchanger is known in which a plurality of heat transfer plates are stacked at predetermined intervals and flow paths for a first fluid and flow paths for a second fluid are alternately formed in a stacking direction to perform heat exchange between the two fluids.

[0003] Regarding a plate heat exchanger, when refrigerant and water are used as fluids, the volume expansion of frozen water may cause the heat transfer plate to break, thereby causing the refrigerant to leak. Patent document 1 (Japanese Patent Publication No. 10-132476) discloses, as embodiment 5, a heat exchanger having a heat transfer plate that can absorb the stress of frozen water by elastic deformation, thereby suppressing breakage, even if the volume of frozen water expands. Summary of the invention

[0004] Problems to be solved by the invention

[0005] Even with the heat transfer plate disclosed in Patent Document 1, since there is a limit to the range in which stress can be absorbed (the range in which elastic deformation can be performed), damage to the heat transfer plate cannot be sufficiently suppressed, and there is a possibility that the refrigerant may leak.

[0006] The present disclosure provides a heat exchanger that suppresses leakage of refrigerant when water freezes and expands in volume.

[0007] Means for solving problems

[0008] The heat exchanger of the first aspect is a heat exchanger for performing heat exchange between water and refrigerant, wherein the heat exchanger comprises: a first flow path through which water flows; and a second flow path through which refrigerant flows. Any component of the components other than the partition wall that separates the first flow path and the second flow path, or any joint portion of the joint portions formed by the components forming the first flow path being joined together, functions as a weak portion having a lower strength than other components forming the first flow path.

[0009] In the present heat exchanger, when water freezes and expands in volume, any one of the components other than the partition wall that separates the first flow path from the second flow path, which functions as a fragile portion, or any one of the joints formed by the components forming the first flow path being joined together, breaks before other portions. Therefore, according to the present heat exchanger, when water freezes and expands in volume, it is possible to suppress the situation in which the components forming the second flow path, the joints forming the second flow path, or the partition wall break and cause refrigerant leakage.

[0010] The heat exchanger of the second aspect is that, in the heat exchanger of the first aspect, the first flow path is formed using two partition walls, an inner fin, and a separation component. The inner fin is stacked between the two partition walls, and its cross section is formed into a corrugated shape. The separation component is arranged at the end edges of the two partition walls to separate the two partition walls.

[0011] A heat exchanger according to a third aspect is the heat exchanger according to the second aspect, wherein the fragile portion is an inner fin.

[0012] According to the heat exchanger, when water freezes and expands in volume, the inner fins forming the first flow path rupture before other portions, thereby preventing refrigerant leakage due to rupture of members forming the second flow path or joints.

[0013] The heat exchanger according to the fourth aspect is, in the heat exchanger according to the third aspect, when the wall thickness of the inner fin is tw, the interval between the tops of the inner fins connected to the same partition wall is Lw, the wall thickness of the partition wall is tR, and the height in the stacking direction of the inner fins is hw, they satisfy the following relationship:

[0014] tw / Lw<tR / hw.

[0015] By forming the dimensions of each part to satisfy the above relationship, the stress generated in the partition wall when the water freezes and expands in volume can be made smaller than the stress generated in the inner fin. Thus, the inner fin that ruptures before the partition wall can absorb the force generated by the volume expansion, thereby preventing the component or joint forming the second flow path from rupturing and causing refrigerant leakage.

[0016] A heat exchanger according to a fifth aspect is the heat exchanger according to the second aspect, wherein the fragile portion is a separation member.

[0017] According to the heat exchanger, when water freezes and expands in volume, the separation member forming the first flow path ruptures before other portions, thereby preventing the member forming the second flow path or the joint from rupturing and causing refrigerant leakage.

[0018] The heat exchanger according to the sixth aspect is, in the heat exchanger according to the fifth aspect, when the width of the separation member in a plan view is Lsp, the wall thickness of the inner fin is tw, the interval between the tops of the inner fins connected to the same partition wall is Lw, the wall thickness of the partition wall is tR, and the height of the inner fin in the stacking direction is hw, they satisfy the following relationship:

[0019] ((Lsp+tw) / Lw)<tR / hw.

[0020] By forming the dimensions of each part to satisfy the above relationship, the stress generated in the partition wall when the water freezes and expands in volume can be made smaller than the stress generated in the separation component. Thus, the separation component that ruptures before the partition wall can absorb the force generated by the volume expansion, thereby preventing the component or joint forming the second flow path from rupturing and causing refrigerant leakage.

[0021] The heat exchanger of the seventh aspect is that, in the heat exchanger of the first aspect, the first flow path is formed using two partition walls, an inner fin, and a separation component. The inner fin is stacked between the two partition walls, and its cross section is formed into a waveform. The separation component is arranged at the end edges of the two partition walls to separate the two partition walls. In addition, the heat exchanger has a first joint and a second joint. The first joint is a portion where the partition wall is joined to the top of the inner fin. The second joint is a portion where the partition wall is joined to the separation component.

[0022] A heat exchanger according to an eighth aspect is the heat exchanger according to the seventh aspect, wherein the fragile portion is the first joining portion.

[0023] According to this heat exchanger, when water freezes and expands in volume, the first joint that joins the members forming the first flow path ruptures earlier than other portions, thereby preventing the members forming the second flow path or the joint from rupturing and causing refrigerant leakage.

[0024] The heat exchanger of the ninth aspect is the heat exchanger of the eighth aspect, wherein the first joint is joined by brazing. If the width of the first joint is bw1, the interval between the tops of the inner fins that are in contact with the same partition wall is Lw, the wall thickness of the partition wall is tR, and the height of the inner fin in the stacking direction is hw, they satisfy the following relationship:

[0025] 0.35×bw1 / (2×Lw)<tR / hw.

[0026] By forming the dimensions of each part to satisfy the above relationship, the stress generated in the partition wall when the water freezes and expands in volume can be made smaller than the stress generated in the first joint. Thus, the first joint that ruptures before the partition wall can absorb the force generated by the volume expansion, thereby preventing the component or joint forming the second flow path from rupturing and causing refrigerant leakage.

[0027] The heat exchanger of the tenth aspect is the heat exchanger of the eighth aspect, wherein the first joint is joined by diffusion joining. If the width of the first joint is bw1, the interval between the tops of the inner fins connected to the same partition wall is Lw, the wall thickness of the partition wall is tR, and the height of the inner fin in the stacking direction is hw, they satisfy the following relationship:

[0028] bw1 / (2×Lw)<tR / hw.

[0029] By forming the dimensions of each part to satisfy the above relationship, the stress generated in the partition wall when the water freezes and expands in volume can be made smaller than the stress generated in the first joint. Thus, the first joint that ruptures before the partition wall can absorb the force generated by the volume expansion, thereby preventing the component or joint forming the second flow path from rupturing and causing refrigerant leakage.

[0030] The heat exchanger according to an eleventh aspect is the heat exchanger according to the seventh aspect, wherein the fragile portion is the second joining portion.

[0031] According to this heat exchanger, when water freezes and expands in volume, the second joint that joins the members forming the first flow path ruptures earlier than other portions, thereby preventing the members forming the second flow path or the joint from rupturing and causing refrigerant leakage.

[0032] The heat exchanger of the 12th aspect is the heat exchanger of the 11th aspect, wherein the second joint is joined by brazing. If the width of the second joint is bsp2, the width of the first joint is bw1, the interval between the tops of the inner fins connected to the same partition wall is Lw, the wall thickness of the partition wall is tR, and the height of the inner fin in the stacking direction is hw, they satisfy the following relationship:

[0033] 0.35×(2×bsp2+bw1) / Lw<2×tR / hw.

[0034] By forming the dimensions of each part to satisfy the above relationship, the stress generated in the partition wall when the water freezes and expands in volume can be made smaller than the stress generated in the second joint portion. Thus, the second joint portion that ruptures earlier than the partition wall can absorb the force generated by the volume expansion, thereby suppressing the situation in which the component or joint portion forming the second flow path ruptures and causes refrigerant leakage.

[0035] The heat exchanger of the 13th aspect is the heat exchanger of the 11th aspect, wherein the second joint is joined by diffusion joining. If the width of the second joint is bsp2, the width of the first joint is bw1, the interval between the tops of the inner fins connected to the same partition wall is Lw, the wall thickness of the partition wall is tR, and the height of the inner fin in the stacking direction is hw, they satisfy the following relationship:

[0036] (2×bsp2+bw1) / Lw<2×tR / hw.

[0037] By forming the dimensions of each part to satisfy the above relationship, the stress generated in the partition wall when the water freezes and expands in volume can be made smaller than the stress generated in the second joint portion. Thus, the second joint portion that ruptures earlier than the partition wall can absorb the force generated by the volume expansion, thereby suppressing the situation in which the component or joint portion forming the second flow path ruptures and causes refrigerant leakage.

[0038] The heat exchanger of the 14th aspect is a heat exchanger of the 1st aspect, wherein the 1st flow path is formed by using two heat transfer plates. The heat exchanger has a 3rd joint and a 4th joint. The two heat transfer plates are stacked on each other, and each cross section is formed into a corrugated shape. The 3rd joint is a portion where the tops of the two heat transfer plates are joined. The 4th joint is a portion where the end edges of the two heat transfer plates are joined.

[0039] The heat exchanger according to a fifteenth aspect is the heat exchanger according to the fourteenth aspect, wherein the fragile portion is a third joining portion.

[0040] According to the present heat exchanger, when water freezes and expands in volume, the third joint 210d formed by joining the components forming the first flow path together breaks earlier than other portions, thereby preventing the components or joints forming the second flow path from breaking and causing refrigerant leakage.

[0041] The heat exchanger of the 16th aspect is the heat exchanger of the 15th aspect, wherein the third joint portion is joined by brazing. If the width of the third joint portion when viewed along the normal direction is bw3 and the wall thickness of the heat transfer plate is t, they satisfy the following relationship:

[0042] 0.35×bw3<2×t.

[0043] By forming the dimensions of each part so as to satisfy the above relationship, the stress generated in the heat transfer plate when the water freezes and expands in volume can be made smaller than the stress generated in the third joint portion. As a result, the third joint portion that is broken before the heat transfer plate can absorb the force generated by the volume expansion, so that the refrigerant leakage caused by the breakage of the member or joint portion forming the second flow path can be suppressed.

[0044] The heat exchanger of the 17th aspect is the heat exchanger of the 15th aspect, wherein the third joint portion is joined by diffusion joining. If the width of the third joint portion when viewed along the normal direction is bw3 and the wall thickness of the heat transfer plate is t, they satisfy the following relationship:

[0045] bw3<2×t.

[0046] By forming the dimensions of each part so as to satisfy the above relationship, the stress generated in the heat transfer plate when the water freezes and expands in volume can be made smaller than the stress generated in the third joint portion. As a result, the third joint portion, which is broken before the heat transfer plate, can absorb the force generated by the volume expansion, so that the refrigerant leakage caused by the breakage of the member or joint portion forming the second flow path can be suppressed.

[0047] The heat exchanger according to an eighteenth aspect is the heat exchanger according to the fourteenth aspect, wherein the fragile portion is a fourth joining portion.

[0048] According to the heat exchanger, when water freezes and expands in volume, the fourth joint 210e formed by joining the components forming the first flow path together breaks earlier than other parts, thereby preventing the components or joints forming the second flow path from breaking and causing refrigerant leakage.

[0049] The heat exchanger of the 19th aspect is the heat exchanger of the 18th aspect, wherein the fourth joint is joined by brazing. If the width of the fourth joint when viewed along the normal direction is bsp4, the width of the third joint when viewed along the normal direction is bw3, and the wall thickness of the heat transfer plate is t, they satisfy the following relationship:

[0050] 0.35×(bsp4+bw3 / 2)<2×t.

[0051] By forming the dimensions of each part so as to satisfy the above relationship, the stress generated in the heat transfer plate when the water freezes and expands in volume can be made smaller than the stress generated in the fourth joint portion. As a result, the fourth joint portion that is broken before the heat transfer plate can absorb the force generated by the volume expansion, so that the refrigerant leakage caused by the breakage of the member or joint portion forming the second flow path can be suppressed.

[0052] The heat exchanger of the 20th aspect is the heat exchanger of the 18th aspect, wherein the fourth joint portion is joined by diffusion joining. If the width of the fourth joint portion when viewed along the normal direction is bsp4, the width of the third joint portion when viewed along the normal direction is bw3, and the wall thickness of the heat transfer plate is t, they satisfy the following relationship:

[0053] (bsp4+bw3 / 2)<2×t.

[0054] By forming the dimensions of each part so as to satisfy the above relationship, the stress generated in the heat transfer plate when the water freezes and expands in volume can be made smaller than the stress generated in the fourth joint portion. As a result, the fourth joint portion that is broken before the heat transfer plate can absorb the force generated by the volume expansion, so that the refrigerant leakage caused by the breakage of the member or joint portion forming the second flow path can be suppressed.

[0055] The heat exchanger according to the 21st aspect is the heat exchanger according to the 1st aspect, wherein the heat exchanger comprises a first heat transfer plate and a second heat transfer plate. The first heat transfer plate has a first flow path formed therein. The second heat transfer plate has a second flow path formed therein. The fragile portion is the first heat transfer plate.

[0056] According to the heat exchanger, when water freezes and expands in volume, the first heat transfer plate forming the first flow path ruptures earlier than other portions, thereby preventing the second heat transfer plate forming the second flow path from rupturing and causing refrigerant leakage.

[0057] The heat exchanger according to a 22nd aspect is the heat exchanger according to the 21st aspect, wherein the first heat transfer plate is formed by laminating two plate-like members having grooves formed therein, wherein the grooves form the first flow path. The fragile portion is a portion where the two plate-like members are joined.

[0058] According to this heat exchanger, when water freezes and expands in volume, the joined portion of the two plate-like members forming the first heat transfer plate breaks earlier than other portions, thereby preventing the second heat transfer plate forming the second flow path from breaking and causing refrigerant leakage.

[0059] A heat exchanger according to a 23rd aspect is the heat exchanger according to any one of the 1st to 22nd aspects, wherein the refrigerant is flammable or toxic.

[0060] According to the present heat exchanger, even when a flammable or toxic refrigerant is used, it is possible to suppress the refrigerant from leaking due to rupture of a member or a joint forming the second flow path 121 .

[0061] A heat exchanger according to a 24th aspect is the heat exchanger according to any one of the 1st to 23rd aspects, wherein the fragile portion is formed to have a strength that allows it to break when water freezes. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 1 is a schematic diagram showing the configuration of a refrigeration cycle device 1 including a heat exchanger 100 .

[0063] Figure 2 It is a perspective view of the heat exchanger 100 .

[0064] Figure 3 yes Figure 2 An enlarged view of part A.

[0065] Figure 4 It is a cross-sectional view showing the first inner fin 110 housed in the heat exchanger 100 .

[0066] Figure 5It is a cross-sectional view showing the second inner fin 120 housed in the heat exchanger 100 .

[0067] Figure 6 Yes Figure 3 A cross-sectional view of the heat exchanger 100 cut along line BB'.

[0068] Figure 7 It is an exploded perspective view of the heat exchanger 200 .

[0069] Figure 8 is a cross-sectional view of the heat exchanger 200 .

[0070] Fig. 9 It is a perspective view of the heat exchanger 300 .

[0071] Fig.10 yes Fig. 9 An enlarged view of part C.

[0072] Fig.11 Yes Fig.10 The heat exchanger 300 is a cross-sectional view taken along line DD'. DETAILED DESCRIPTION

[0073] <First embodiment>

[0074] (1) Refrigeration cycle device 1

[0075] First, a refrigerant cycle device 1 having a heat exchanger 100 according to a first embodiment of the present disclosure is described. The refrigerant cycle device 1 heats or cools water supplied from outside the refrigerant cycle device 1, such as city water (tap water), and supplies the water. The refrigerant cycle device 1 includes a water intake portion 1a, a water supply portion 1b, a heat exchanger 100, a refrigerant circuit 10, a water circuit 20, a water supply portion 30, and a control portion 40. Although not limited, in the present embodiment, the water supply portion 30 is disposed indoors, and the water circuit 20 and the refrigerant circuit 10 are disposed outdoors. As will be described in detail later, the refrigerant circulates in the refrigerant circuit 10, and the water circulates in the water circuit 20.

[0076] The water intake unit 1a takes water supplied from the outside into the refrigeration cycle device 1. The water supply unit 1b supplies water heated or cooled by the refrigeration cycle device 1 to the outside.

[0077] (1-1) Heat exchanger 100

[0078] The heat exchanger 100 exchanges heat between the refrigerant circulating in the refrigerant circuit 10 and the water circulating in the water circuit 20. The heat exchanger 100 includes first flow tubes 170a and 170b, second flow tubes 180a and 180b, a first flow path 111, and a second flow path 121.

[0079] The first flow path 111 is a flow path through which water flows. The first flow path 111 is provided between the first flow tube 170a and the first flow tube 170b.

[0080] The second flow path 121 is a flow path through which the refrigerant flows. The second flow path 121 is formed between the second flow tube 180a and the second flow tube 180b. The detailed structure of the heat exchanger 100 will be described later.

[0081] (1-2) Refrigerant Circuit 10

[0082] In the refrigerant circuit 10, the refrigerant is heated or cooled. The refrigerant circuit 10 is composed of a compressor 11, a four-way switching valve 12, a heat source heat exchanger 13, an expansion valve 14, and a second flow path 121 of the heat exchanger 100. The compressor 11, the four-way switching valve 12, the heat source heat exchanger 13, the expansion valve 14, and the second flow path 121 of the heat exchanger 100 are connected by pipes, and the refrigerant circulates inside. In this embodiment, the refrigerant is propane.

[0083] The compressor 11 sucks low-pressure refrigerant in the refrigerant circuit 10 from the suction portion 11 a , compresses the refrigerant, and discharges the refrigerant from the discharge portion 11 b as high-pressure refrigerant.

[0084] The four-way switching valve 12 has a first port P1, a second port P2, a third port P3, and a fourth port P4. The four-way switching valve 12 switches between a first state and a second state in which the communication states of the first port P1, the second port P2, the third port P3, and the fourth port P4 are different, based on an instruction from the control unit 40. In the first state, the first port P1 is communicated with the second port P2, and the third port P3 is communicated with the fourth port P4. In the second state, the first port P1 is communicated with the fourth port P4, and the second port P2 is communicated with the third port P3.

[0085] The first port P1 is connected to the discharge portion 11b of the compressor 11. The second port P2 is connected to the second flow pipe 180a of the heat exchanger 100. The third port P3 is connected to the suction portion 11a of the compressor 11. The fourth port P4 is connected to one end of the heat source heat exchanger 13.

[0086] The heat source heat exchanger 13 exchanges heat between the refrigerant circulating in the refrigerant circuit 10 and a heat source (for example, outdoor air).

[0087] The expansion valve 14 adjusts the flow rate of the refrigerant circulating in the refrigerant circuit 10 and functions as a decompression device that decompresses the refrigerant.

[0088] One end of the expansion valve 14 is connected to the other end of the heat source heat exchanger 13. The other end of the expansion valve 14 is connected to the second flow pipe 180b of the heat exchanger 100.

[0089] (1-3) Water circuit 20

[0090] Water that has exchanged heat with the refrigerant circulates in the water circuit 20. The water circuit 20 is composed of the first flow path 111 of the heat exchanger 100, the water circulation pump 21, the flow rate regulating valve 22, and the heat exchanger 23. The first flow path 111 of the heat exchanger 100, the water circulation pump 21, the flow rate regulating valve 22, and the heat exchanger 23 are connected by pipes, and water circulates therein.

[0091] The water circulation pump 21 circulates water inside the water circuit 20. The water circulation pump 21 sucks water inside the water circuit 20 from the suction part 21a, and discharges it from the discharge part 21b.

[0092] The suction portion 21a is connected to the first flow pipe 170a of the heat exchanger 100. The discharge portion 21b is connected to one end of the flow rate regulating valve 22.

[0093] The flow rate regulating valve 22 regulates the flow rate of water circulating in the water circuit 20 .

[0094] The heat exchanger 23 exchanges heat between water circulating in the water circuit 20 and water stored in a water tank 31 (described later) of the water supply unit 30. The heat exchanger 23 is arranged inside the water tank 31 so that water passing through the inside can exchange heat with water stored in the water tank 31.

[0095] One end of the heat exchanger 23 is connected to the other end of the flow rate regulating valve 22. The other end of the heat exchanger 23 is connected to the first flow pipe 170b of the heat exchanger 100.

[0096] The water circuit 20 may further include a heat exchanger for heating or cooling the indoor air using the circulating water.

[0097] (1-4) Water supply unit 30

[0098] The water supply unit 30 exchanges heat between water supplied from the outside of the refrigeration cycle device 1 and water circulating in the water circuit 20, and then supplies the water to the outside of the refrigeration cycle device 1. The water supply unit 30 is composed of a water storage tank 31, a water supply pump 32, and a mixing valve 33. The water storage tank 31, the water supply pump 32, and the mixing valve 33 are connected by pipes.

[0099] The water storage tank 31 stores water supplied from the outside. The stored water exchanges heat with the water passing through the heat exchanger 23. The water storage tank 31 takes in and stores water supplied from the outside from the water inlet 31a. The stored water exchanges heat with the water passing through the heat exchanger 23 and is discharged from the water outlet 81b.

[0100] The water inlet portion 31a is connected to the water intake portion 1a to which water is supplied from the outside.

[0101] The water supply pump 32 sucks water stored in the water storage tank 31 and supplies the water to the mixing valve 33. The water supply pump 32 sucks water in the water storage tank 31 from the suction part 32a and discharges the water from the discharge part 32b.

[0102] The suction portion 32a is connected to the water discharge portion 31b. The discharge portion 32b is connected to a second port 33b (described later) of the mixing valve 33.

[0103] The mixing valve 33 mixes water supplied from the outside with water stored in the water storage tank 31. The mixing valve 33 has a first port 33a, a second port 33b, and a third port 33c.

[0104] The first port 33a is connected to the water intake portion 1a supplied with water from the outside. The second port 33b is connected to the discharge portion 32b of the water supply pump 32. The third port 33c is connected to the water supply portion 1b communicating with the outside of the refrigeration cycle device 1.

[0105] (1-5) Control Unit 40

[0106] The control unit 40 controls the compressor 11, the four-way switching valve 12, the expansion valve 14, the water circulation pump 21, the flow regulating valve 22, the water supply pump 32, and the mixing valve 33. Although not shown in the figure, the control unit 40 is electrically connected to the compressor 11, the four-way switching valve 12, the expansion valve 14, the water circulation pump 21, the flow regulating valve 22, the water supply pump 32, and the mixing valve 33 in a manner capable of sending and receiving control signals.

[0107] (1-6) Operation of Refrigeration Cycle Device 1

[0108] The refrigeration cycle device 1 performs a heating operation, a cooling operation, and a defrosting operation.

[0109] (1-6-1) Heating operation

[0110] The heating operation is an operation in which the refrigerant cycle device 1 heats water supplied from the outside to the water intake portion 1a and then supplies it from the water supply portion 1b. In the heating operation, the control unit 40 sets the four-way switching valve 12 to the first state, drives the compressor 11, the water circulation pump 21, and the water supply pump 32, and controls the opening of the expansion valve 14, the flow control valve 22, and the mixing valve 33.

[0111] (1-6-1-1) Refrigerant Circuit 10

[0112] The compressor 11 sucks the low-pressure gas-phase refrigerant in the refrigerant circuit 10 from the suction portion 11a and discharges it from the discharge portion 11b as the high-pressure gas-phase refrigerant. The high-pressure gas-phase refrigerant passes through the four-way switching valve 12 in the order of the first port P1 and the second port P2 and reaches the second flow path 121 of the heat exchanger 100. In the second flow path 121 of the heat exchanger 100, the high-pressure gas-phase refrigerant condenses and becomes a high-pressure liquid-phase refrigerant. At this time, the refrigerant releases heat to the water passing through the first flow path 111. The high-pressure liquid-phase refrigerant reaches the expansion valve 14. The expansion valve 14 set to an appropriate opening reduces the pressure of the high-pressure liquid-phase refrigerant to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant evaporates in the heat source heat exchanger 13 to become a low-pressure gas-phase refrigerant. At this time, the refrigerant absorbs heat from the heat source (external air). The low-pressure gas-phase refrigerant passes through the four-way switching valve 12 in this order through the fourth port P4 and the third port P3 , and is then sucked into the compressor 11 from the suction portion 11 a .

[0113] (1-6-1-2) Water circuit 20

[0114] The water circulation pump 21 sucks water circulating in the water circuit 20 from the suction part 21a and discharges it from the discharge part 21b. The discharged water passes through the flow control valve 22 and reaches the heat exchanger 23. The water reaching the heat exchanger 23 releases heat to the water stored in the water storage tank 31 in the heat exchanger 23. In other words, the water reaching the heat exchanger 23 heats the water stored in the water storage tank 31 in the heat exchanger 23. The water that has released heat in the heat exchanger 23 reaches the first flow path 111 of the heat exchanger 100. The water reaching the first flow path 111 of the heat exchanger 100 absorbs heat from the refrigerant passing through the second flow path 121. The water that has absorbed heat is sucked into the water circulation pump 21 from the suction part 21a.

[0115] (1-6-1-3) Water supply department 30

[0116] The water stored in the water storage tank 31 is heated by absorbing heat from the water passing through the heat exchanger 23. The water supply pump 32 draws the water heated in the water storage tank 31 from the suction part 32a. The water drawn into the water supply pump 32 is discharged from the discharge part 32b to the mixing valve 33. The water discharged from the water supply pump 32 passes through the second port 33b and is mixed with the water from the outside that reaches the first port 33a through the water intake part 1a. The water mixed by the mixing valve 33 passes through the third port 33c and is supplied from the water supply part 1b to the outside of the refrigeration cycle device 1.

[0117] (1-6-2) Cooling operation

[0118] The cooling operation is an operation in which the refrigerant cycle device 1 cools water supplied from the outside to the water intake portion 1a and supplies it from the water supply portion 1b. In the cooling operation, the control unit 40 sets the four-way switching valve 12 to the second state, drives the compressor 11, the water circulation pump 21, and the water supply pump 32, and controls the opening of the expansion valve 14, the flow control valve 22, and the mixing valve 33.

[0119] (1-6-2-1) Refrigerant circuit 10

[0120] The compressor 11 sucks the low-pressure gas-phase refrigerant in the refrigerant circuit 10 from the suction portion 11a and discharges it from the discharge portion 11b as the high-pressure gas-phase refrigerant. The high-pressure gas-phase refrigerant passes through the four-way switching valve 12 in the order of the first port P1 and the fourth port P4 and reaches the heat source heat exchanger 13. In the heat source heat exchanger 13, the high-pressure gas-phase refrigerant condenses and becomes a high-pressure liquid-phase refrigerant. At this time, the refrigerant releases heat to the heat source (external air). The high-pressure liquid-phase refrigerant reaches the expansion valve 14. The expansion valve 14, which is set to an appropriate opening, decompresses the high-pressure liquid-phase refrigerant and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant evaporates in the second flow path 121 of the heat exchanger 100 and becomes a low-pressure gas-phase refrigerant. At this time, the refrigerant absorbs heat from the water passing through the first flow path 111. The low-pressure gas-phase refrigerant passes through the four-way switching valve 12 in the order of the second port P2 and the third port P3 , and is then sucked into the compressor 11 from the suction portion 11 a .

[0121] (1-6-2-2) Water circuit 20

[0122] The water circulation pump 21 sucks water circulating in the water circuit 20 from the suction part 21a and discharges it from the discharge part 21b. The discharged water reaches the heat exchanger 23 through the flow control valve 22. The water reaching the heat exchanger 23 absorbs heat from the water stored in the water storage tank 31 in the heat exchanger 23. In other words, the water reaching the heat exchanger 23 cools the water stored in the water storage tank 31 in the heat exchanger 23. The water that has absorbed heat in the heat exchanger 23 reaches the first flow path 111 of the heat exchanger 100. The water that has reached the first flow path 111 of the heat exchanger 100 releases heat to the refrigerant passing through the second flow path 121. The water that has released heat is sucked into the water circulation pump 21 from the suction part 21a.

[0123] (1-6-2-3) Water supply department 30

[0124] The water stored in the water storage tank 31 is cooled by releasing heat to the water passing through the heat exchanger 23. The water supply pump 32 sucks the water cooled in the water storage tank 31 from the suction part 32a. The water sucked into the water supply pump 32 is discharged from the discharge part 32b to the mixing valve 33. The water discharged from the water supply pump 32 passes through the second port 33b and is mixed with the water from the outside that reaches the first port 33a through the water intake part 1a. The water mixed by the mixing valve 33 passes through the third port 33c and is supplied from the water supply part 1b to the outside of the refrigeration cycle device 1.

[0125] (1-6-3) Defrost operation

[0126] The defrosting operation is an operation for melting and removing the frost attached to the surface of the heat source heat exchanger 13 during the heating operation by using the heat of the refrigerant condensed in the heat source heat exchanger 13. The operation of each part of the refrigerant cycle device 1 during the defrosting operation is the same as that of the cooling operation described above. Therefore, a detailed description of the defrosting operation is omitted.

[0127] (2) Heat exchanger

[0128] (2-1) Overall structure

[0129] The heat exchanger 100 is a heat exchanger including a plurality of first inner fins 110, a plurality of second inner fins 120, a plurality of partition walls 130, a first separation member 140, a second separation member 150, a housing 160, a first flow tube 170a, a first flow tube 170b, a second flow tube 180a, and a second flow tube 180b. The heat exchanger 100 has a first flow path 111 through which water flows and a second flow path 121 through which a refrigerant flows formed therein. As will be described in detail later, the heat exchanger 100 has a fragile portion 190 that prevents the refrigerant flowing in the second flow path 121 from flowing into the first flow path 111 when water freezes.

[0130] The first inner fin 110, the second inner fin 120 and the partition wall 130 are metal plate-like members having the same rectangular shape. Figure 2 As shown, the outer shapes of the first inner fins 110 , the second inner fins 120 , and the partition walls 130 are formed in a rectangular shape that is long in the first direction.

[0131] The first inner fins 110 and the second inner fins 120 are alternately stacked with the partition walls 130 interposed therebetween, and are housed in the housing 160. The number of each of the first inner fins 110 and the second inner fins 120 is not particularly limited, and is appropriately set according to required performance.

[0132] In the following description, for convenience, the first direction is sometimes referred to as the length direction DL. In addition, the direction orthogonal to the first direction is sometimes referred to as the width direction DW. Also, the direction in which the first inner fin 110, the partition wall 130, and the second inner fin 120 are stacked is sometimes referred to as the stacking direction DS. The length direction DL, the width direction DW, and the stacking direction DS correspond to the directions indicated by the arrows in the respective figures. The directions of the back, front, left, and right used in the following description correspond to the directions of the back, front, left, and right used in the respective figures. Figures 2 to 5 The direction indicated by the arrow in .

[0133] (2-2) Detailed structure

[0134] (2-2-1) First inner fin 110

[0135] The first inner fin 110 is a corrugated fin having a corrugated cross section. The corrugation of the first inner fin 110 is formed so that the top 110t of the corrugation extends along the longitudinal direction DL when viewed from above. The first inner fin 110 forms a first flow path 111 together with the adjacently stacked partition walls 130 and the first separation member 140 isolating the partition walls 130. The first inner fin 110 is not limited and may be formed, for example, by press working.

[0136] It should be noted that regarding the shape of the first inner fin 110, the "waveform" is not limited to Figure 6 The shape in which semicircular concavities and convexities are periodically arranged as shown may be a shape that changes periodically in a sinusoidal wave, a rectangular wave, a triangular wave, or the like. This also applies to the second inner fin 120 .

[0137] (2-2-2) Second inner fin 120

[0138] The second inner fin 120 is a corrugated fin having a corrugated cross section. The corrugation of the second inner fin 120 is formed so that the top 120t of the corrugation extends along the width direction DW when viewed from above. The second inner fin 120 forms a second flow path 121 together with the adjacently stacked partition wall 130. The second inner fin 120 is not limited and may be formed, for example, by press working.

[0139] (2-2-3) Partition wall 130

[0140] The partition wall 130 is a flat plate that separates the first inner fin 110 and the second inner fin 120 in the stacking direction DS.

[0141] (2-2-4) First Separation Component 140

[0142] The first separation member 140 is a member for isolating two partition walls 130 in order to arrange the first inner fin 110 between the partition walls 130 adjacent to each other in the stacking direction DS. The first separation member 140 is a strip-shaped member extending in the length direction DL. The first separation member 140 is arranged along both end edges in the width direction DW of the partition wall 130. The height of the first separation member 140 in the stacking direction DS is formed to be the same as the height of the first inner fin 110 in the stacking direction DS. The first inner fin 110 is arranged between the first separation members 140 arranged along both end edges in the width direction DW of the partition wall 130.

[0143] (2-2) Second separation member 150

[0144] The second separation member 150 is a member for isolating two partition walls 130 in order to arrange the second inner fin 120 between the partition walls 130 adjacent to each other in the stacking direction DS. The second separation member 150 is a strip-shaped member extending in the width direction DW. The second separation member 150 is arranged along both end edges in the length direction DL of the partition wall 130. The height of the second separation member 150 in the stacking direction DS is formed to be the same as the height of the second inner fin 120 in the stacking direction DS. The first inner fin 110 is arranged between the second separation members 150 arranged along both end edges in the length direction DL of the partition wall 130.

[0145] (2-2-6) Housing 160

[0146] The shell 160 is a substantially rectangular parallelepiped member that accommodates the first inner fin 110, the second inner fin 120, the partition wall 130, the first separation member 140, and the second separation member 150. The shell 160 has two main surfaces 160a, two first side surfaces 160b, and two second side surfaces 160c that are orthogonal to the stacking direction DS. The main surface 140a is a surface orthogonal to the stacking direction DS. The first side surface 160b is a surface orthogonal to the length direction DL. The second side surface 160c is a surface orthogonal to the width direction DW. The shell 160 has a first header 141, a second header 142, a third header 143, a fourth header 144, and a fifth header 145 formed therein.

[0147] The first header 141 is a space for branching water flowing into the housing 160 to the plurality of first flow paths 111. The first header 141 is formed along the first side surface 160b on the inner side.

[0148] The second header 142 is a space where water passing through the first flow path 111 merges. The second header 142 is formed along the first side surface 160b on the near side.

[0149] The third header 143 is a space for branching the refrigerant flowing into the shell 160 into the plurality of second flow paths 121. The third header 143 is formed along the inner side of the second side surface 160c on the right side.

[0150] The fourth header 144 is a space where the refrigerants passing through the second flow paths 121 merge. The fourth header 144 is formed along the front side of the second side surface 160c on the right side.

[0151] The fifth header 145 is a space where the refrigerant passing through the second flow path 121 changes its flow direction after merging and branches to the second flow path 121 again. The fifth header 145 includes a fifth header 145a, a fifth header 145b, and a fifth header 145c. Figure 5 As shown, the fifth header 145a is formed along the back side of the left second side surface 160c. The fifth header 145b is formed along the right second side surface 160c between the fourth header 144 and the fifth header 145. The fifth header 145c is formed along the front side of the left second side surface 160c.

[0152] (2-2-7) First Flow Tube 170a and First Flow Tube 170b

[0153] The first flow pipe 170a is a pipe that allows water to flow to the first flow path 111. The first flow pipe 170a is provided in the housing 160 so as to penetrate the first side surface 160b on the near side and communicate with the first header 141.

[0154] The first flow pipe 170b is a pipe for flowing water to the first flow path 111. The first flow pipe 170b is provided in the housing 160 so as to penetrate the first side surface 160b on the inner side and communicate with the second header 142.

[0155] (2-2-8) Second flow tube 180a and second flow tube 180b

[0156] The second flow pipe 180a is a pipe that allows the refrigerant to flow to the second flow path 121. The second flow pipe 180a is provided in the casing 160 so as to penetrate the second side surface 160c on the right side and communicate with the third header 143.

[0157] The second flow pipe 180b is a pipe for flowing water to the second flow path 121. The second flow pipe 180b is provided in the casing 160 so as to penetrate the second side surface 160c on the right side and communicate with the fourth header 144.

[0158] (2-2-9) First flow path 111 and second flow path 121

[0159] The first inner fin 110 is accommodated in a space surrounded by two partition walls 130 adjacent to each other in the stacking direction DS and two first separation components 140 disposed between the partition walls 130, thereby forming a plurality of first flow paths 111 arranged in the width direction DW. The first flow path 111 is a space extending in the length direction DL surrounded by the first inner fin 110 and the partition walls 130, and a space extending in the length direction DL surrounded by the first inner fin 110, the partition walls 130, and the first separation component 140.

[0160] In the present embodiment, the first inner fin 110, the partition wall 130 and the first separation component 140 are joined together by brazing. More specifically, the corrugated top 110t of the first inner fin 110 is joined to the partition wall 130 by brazing. The surface of the first separation component 140 perpendicular to the stacking direction DS is joined to the partition wall 130 by brazing. Hereinafter, for convenience, the portion where the top 110t is joined to the partition wall 130 is referred to as the first joint portion 110c, and the portion where the partition wall 130 is joined to the first separation component 140 is referred to as the second joint portion 140c. The first joint portion 110c and the second joint portion 140c are examples of joint portions.

[0161] The second inner fin 120 is accommodated in a space surrounded by two partition walls 130 adjacent to each other in the stacking direction DS and two second separation components 150 disposed between the partition walls 130, thereby forming a plurality of second flow paths 121 arranged in the length direction DL. The second flow path 121 is a space extending in the width direction DW surrounded by the second inner fin 120 and the partition wall 130, and a space extending in the width direction DW surrounded by the second inner fin 120, the partition wall 130 and the second separation component 150.

[0162] The plurality of first inner fins 110 and the plurality of second inner fins 120 are alternately stacked with the partition walls 130 interposed therebetween, whereby the plurality of first flow paths 111 arranged in the width direction DW and the plurality of second flow paths 121 arranged in the length direction DL are stacked in a crisscross pattern in the stacking direction DS.

[0163] (2-2-10) Vulnerable Department 190

[0164] The heat exchanger 100 has a weak portion 190 which has lower strength than other portions and which ruptures due to volume expansion caused by freezing of water. The weak portion 190 is any of the components other than the partition wall 130 which forms the first flow path 111 and separates the first flow path 111 from the second flow path 121. In the present embodiment, the first inner fin 110 and the first separation component 140 function as the weak portion 190. In this case, the first inner fin 110 and the first separation component 140 are preferably formed in such a manner that when water expands in volume to a certain level or more, the first inner fin 110 ruptures first, and then the first separation component 140 ruptures.

[0165] In order to make the first inner fin 110 function as the fragile portion 190, the dimensions of the various parts forming the first flow path 111 preferably satisfy the following relationship (Formula 1). Here, the wall thickness of the first inner fin 110 is tw, the interval of the top 110t connected to the same partition wall 130 is Lw, the wall thickness of the partition wall 130 is tR, and the height of the first inner fin in the stacking direction DS is hw.

[0166] tw / Lw<tR / hw…(Formula 1)

[0167] In addition, tw is, for example, 0.15 mm, Lw is, for example, 2 mm, tR is, for example, 0.15 mm, and hw is, for example, 1 mm.

[0168] In order for the first separation member 140 to function as the fragile portion 190, the dimensions of the respective portions forming the first flow path 111 preferably satisfy the following relationship (Formula 2): Here, the width of the first separation member 140 in a plan view is denoted by Lsp.

[0169] ((Lsp+tw) / Lw)<tR / hw…(Formula 2)

[0170] In addition, Lsp is, for example, 0.1 mm.

[0171] (2-3) Flow of refrigerant and water

[0172] The water introduced from the first flow pipe 170a of the heat exchanger 100 flows into the first flow path 111 through the first header 141. The water flowing into the first flow path 111 flows toward the inner side along the length direction DL in the first flow path 111. The water reaching the inner side passes through the second header 142 and is discharged from the first flow pipe 170b. In addition, the water introduced from the first flow pipe 170b of the heat exchanger 100 flows into the first flow path 111 through the second header 142. The water flowing into the first flow path 111 flows toward the near front side along the length direction DL in the first flow path 111. The water reaching the near front side passes through the first header 141 and is discharged from the first flow pipe 170a. In either case, the water flowing in the first flow path 111 performs heat exchange with the refrigerant of the adjacent second flow path 121 via the partition wall 130.

[0173] On the other hand, the refrigerant introduced from the second flow pipe 180a of the heat exchanger 100 flows into the second flow path 121 through the third header 143. The refrigerant flowing into the second flow path 121 flows from the right side to the left side along the width direction DW in the second flow path 121. The refrigerant reaching the left side merges in the fifth header 145a, flows toward the near side along the length direction DL, and is again divided into a plurality of second flow paths 121. The refrigerant flowing from the fifth header 145a into the second flow path 121 flows from the left side to the right side along the width direction DW in the second flow path 121. Similarly, the refrigerant flows in the order of the fifth header 145b, the second flow path 121, the fifth header 145c, and the second flow path 121, repeatedly dividing and merging, and then passes through the fourth header 144 and is discharged from the second flow pipe 180b. In addition, the refrigerant introduced from the second flow pipe 180b of the heat exchanger 100 flows into the second flow path 121 through the fourth header 144. The refrigerant flowing into the second flow path 121 flows from the right side to the left side along the width direction DW in the second flow path 121. The refrigerant reaching the left side merges in the fifth header 145c, flows toward the inner side along the length direction DL, and is again divided into a plurality of second flow paths 121. The refrigerant flowing from the fifth header 145c into the second flow path 121 flows from the left side to the right side along the width direction DW in the second flow path 121. Similarly, the refrigerant flows in the order of the fifth header 145b, the second flow path 121, the fifth header 145a, and the second flow path 121, and then passes through the third header 143 and is discharged from the second flow pipe 180a. In either case, the water flowing in the second flow path 121 exchanges heat with the water in the adjacent first flow path 111 via the partition wall 130 to condense (during the heating operation) or evaporate (during the cooling operation and the defrosting operation).

[0174] (3) Features

[0175] (3-1)

[0176] The heat exchanger 100 is a heat exchanger for performing heat exchange between water and refrigerant, and includes a first flow path 111 through which water flows and a second flow path 121 through which refrigerant flows. Any of the components other than the partition wall 130 that forms the first flow path 111 and separates the first flow path 111 from the second flow path 121 functions as a weak portion 190 having a lower strength than other components that form the first flow path 111.

[0177] In the heat exchanger 100, when the volume expands due to freezing of water in the first flow path 111, any member other than the partition wall 130 that forms the first flow path 111 and separates the first flow path 111 from the second flow path 121, which functions as the fragile portion 190, breaks before other portions. Therefore, according to the heat exchanger 100, when the volume expands due to freezing of water, the member forming the second flow path 121, the joint forming the second flow path 121, or the partition wall 130 breaks, thereby preventing the refrigerant from leaking.

[0178] Although not particularly limited, in the refrigeration cycle device 1, for example, the following situation is envisioned: the water passing through the first flow path 111 may freeze due to cooling operation, defrosting operation, and a decrease in the temperature of the place where the refrigerant circuit 10 is installed. In the cooling operation and defrosting operation, the refrigerant in the second flow path 121 evaporates in the heat exchanger 100 and absorbs heat from the water passing through the first flow path 111 (cooling the water), so the water may freeze. In addition, when the temperature of the place where the refrigerant circuit 10 is installed decreases, the heat exchanger 100 is cooled as the ambient temperature decreases, and the water may freeze.

[0179] (3-2)

[0180] The first flow path 111 of the heat exchanger 100 is formed by two partition walls 130, the first inner fin 110 and the first separation member 140. The first inner fin 110 is stacked between the two partition walls 130 and has a corrugated cross section. The first separation member 140 is disposed at the edge of the two partition walls 130 to separate the two partition walls 130.

[0181] (3-3)

[0182] The fragile portion 190 is the first inner fin 110 .

[0183] According to the heat exchanger 100 , when water freezes and expands in volume, the first inner fins 110 forming the first flow paths 111 rupture earlier than other portions, thereby preventing refrigerant leakage due to rupture of components or joints forming the second flow paths 121 .

[0184] (3-4)

[0185] If the wall thickness of the first inner fin 110 is tw, the interval between the top 110t of the first inner fin 110 connected to the same partition wall 130 is Lw, the wall thickness of the partition wall 130 is tR, and the height of the first inner fin 110 in the stacking direction DS is hw, they satisfy the following relationship:

[0186] tw / Lw<tR / hw…(Formula 1).

[0187] By forming the dimensions of each part so as to satisfy the above relationship, the stress generated in the partition wall 130 when the water freezes and expands in volume can be made smaller than the stress generated in the first inner fin 110 when the water freezes and expands in volume. As a result, the first inner fin 110, which is broken before the partition wall 130, can absorb the force generated by the volume expansion, so that the component or joint forming the second flow path 121 can be prevented from breaking and causing the refrigerant to leak.

[0188] (3-5)

[0189] The fragile portion 190 is the first separation member 140 .

[0190] According to the heat exchanger 100, when water freezes and expands in volume, the first separation member 140 forming the first flow path 111 ruptures before other portions, thereby preventing the member forming the second flow path 121 or the joint from rupturing and causing refrigerant leakage.

[0191] (3-6)

[0192] If the width of the first separation member 140 in a plan view is Lsp, the wall thickness of the first inner fin 110 is tw, the interval between the top 110t of the first inner fin 110 connected to the same partition wall 130 is Lw, the wall thickness of the partition wall 130 is tR, and the height of the first inner fin 110 in the stacking direction is hw, they satisfy the following relationship:

[0193] ((Lsp+tw) / Lw)<tR / hw…(Formula 2).

[0194] By forming the dimensions of each part so as to satisfy the above relationship, the stress generated in the partition wall 130 when the water freezes and expands in volume can be made smaller than the stress generated in the first separation member 140 when the water freezes and expands in volume. As a result, the first separation member 140, which is broken before the partition wall 130, can absorb the force generated by the volume expansion, so that the member or joint forming the second flow path 121 can be prevented from breaking and causing refrigerant leakage.

[0195] (4) Modification

[0196] (4-1) Modification 1A

[0197] In the above embodiment, the first inner fin 110 and the first separation component 140 function as the fragile portion 190, but as long as the component forming the second flow path 121 can be prevented from rupturing, it is also possible to form only one of the first inner fin 110 and the first separation component 140 to function as the fragile portion 190.

[0198] (4-2) Modification 1B

[0199] In the above-mentioned embodiment, the component forming the first flow path 111 functions as the fragile portion 190, but the fragile portion 190 may also be any one of the joints formed by the components forming the first flow path 111 being joined to each other. Specifically, the fragile portion 190 may also be the first joint 110c. In addition, the fragile portion 190 may also be the first joint 110c and the second joint 140c. In this case, it is preferably formed so that if the water produces a certain volume expansion, the first joint 110c is first broken, and then the second joint 140c is broken.

[0200] The heat exchanger 100 of Modification 1B is a heat exchanger that performs heat exchange between water and refrigerant, and includes a first flow path 111 through which water flows and a second flow path 121 through which refrigerant flows. The first joint portion 110c or the second joint portion 140c, which is a joint formed by joining components forming the first flow path 111 to each other, functions as a weak portion having a lower strength than other components forming the first flow path 111.

[0201] In the heat exchanger 100 of Modified Example 1B, when water freezes and expands in volume, the first joint 110c or the second joint 140c functioning as the fragile portion 190 ruptures before other portions. Therefore, according to the heat exchanger 100 of Modified Example 1B, when water freezes and expands in volume, it is possible to suppress the refrigerant leakage caused by the rupture of the component or joint forming the second flow path 121.

[0202] In order for the first joint portion 110c to function as the fragile portion 190, the dimensions of the respective portions forming the first flow path 111 preferably satisfy the following relationship (Formula 3): Here, the width of the first joint portion 110c in a plan view is denoted by bw1.

[0203] 0.35×bw1 / (2×Lw)<tR / hw…(3)

[0204] In addition, bw1 is, for example, 0.035 mm.

[0205] By forming the dimensions of each part so as to satisfy the above relationship, the stress generated in the partition wall 130 when the water freezes and expands in volume can be made smaller than the stress generated in the first joint portion 110c when the water freezes and expands in volume. As a result, the first joint portion 110c, which is broken earlier than the partition wall 130, can absorb the force generated by the volume expansion, thereby preventing the component or joint portion forming the second flow path 121 from breaking and causing refrigerant leakage.

[0206] In order for the second joint portion 140c to function as the fragile portion 190, the dimensions of the respective portions forming the first flow path 111 preferably satisfy the following relationship (Formula 4): Here, the width of the second joint portion 140c in a plan view is denoted by bsp2.

[0207] 0.35×(2×bsp2+bw1) / Lw<2×tR / hw…(Formula 4)

[0208] In addition, bsp2 is, for example, 0.1 mm.

[0209] By forming the dimensions of each part to satisfy the above relationship, the stress generated in the partition wall 130 when the water freezes and expands in volume can be made smaller than the stress generated in the second joint 140c when the water freezes and expands in volume. As a result, the second joint 140c, which is broken earlier than the partition wall 130, can absorb the force generated by the volume expansion, so it is possible to suppress the situation where the component or joint forming the second flow path 121 is broken and causes the refrigerant to leak.

[0210] (4-3) Modification 1C

[0211] In the above embodiment, the first joining portion 110 c and the second joining portion 140 c are joined by brazing, but the first joining portion 110 c and the second joining portion 140 c may be joined by diffusion bonding.

[0212] In the heat exchanger 100 of modification 1C in which the first joint portion 110c and the second joint portion 140c are joined together by diffusion joining, similarly to the heat exchanger 100 of modification 1B, when water freezes and causes volume expansion, the first joint portion 110c or the second joint portion 140c functioning as the fragile portion 190 ruptures earlier than other portions. Therefore, according to the heat exchanger 100 of modification 1B, when water freezes and causes volume expansion, it is possible to suppress the situation in which the component or joint portion forming the second flow path 121 ruptures and causes refrigerant leakage.

[0213] In order for the first joint portion 110 c to function as the fragile portion 190 , the dimensions of each portion forming the first flow path 111 preferably satisfy the following relationship (Formula 5).

[0214] bw1 / (2×Lw)<tR / hw···(5)

[0215] By forming the dimensions of each part so as to satisfy the above relationship, the stress generated in the partition wall 130 when the water freezes and expands in volume can be made smaller than the stress generated in the first joint portion 110c when the water freezes and expands in volume. As a result, the first joint portion 110c, which is broken earlier than the partition wall 130, can absorb the force generated by the volume expansion, thereby preventing the component or joint portion forming the second flow path 121 from breaking and causing refrigerant leakage.

[0216] In order for the second joint portion 140 c to function as the fragile portion 190 , the dimensions of each portion forming the first flow path 111 preferably satisfy the following relationship (Formula 6).

[0217] (2×bsp2+bw1) / Lw<2×tR / hw…(Formula 6)

[0218] By forming the dimensions of each part to satisfy the above relationship, the stress generated in the partition wall 130 when the water freezes and expands in volume can be made smaller than the stress generated in the second joint 140c when the water freezes and expands in volume. As a result, the second joint 140c, which is broken earlier than the partition wall 130, can absorb the force generated by the volume expansion, so it is possible to suppress the situation where the component or joint forming the second flow path 121 is broken and causes the refrigerant to leak.

[0219] (4-4) Modification 1D

[0220] In the above embodiment, the refrigerant used is propane, but the refrigerant used is not limited to this, and a known refrigerant such as HC, HFC (R410A, etc.), HCFC (R22, R32, etc.), natural refrigerant, etc. can be used.

[0221] According to the heat exchanger 100, even when using a flammable or toxic refrigerant, it is possible to suppress leakage of the refrigerant due to rupture of the components or joints forming the second flow path 121. The flammable refrigerant is a refrigerant classified as 2L or more in the US ANSI / ASHRAE34 standard.

[0222] <Second embodiment>

[0223] (1) Heat exchanger

[0224] The heat exchanger 200 of the second embodiment of the present disclosure is described. The main difference between the heat exchanger 100 and the heat exchanger 200 is that the heat exchanger 100 forms a flow path by stacking inner fins and partition walls, whereas the heat exchanger 200 forms a flow path by stacking two heat transfer plates.

[0225] The refrigeration cycle device 1 may include a heat exchanger 200 instead of the heat exchanger 100. The structure and operation of the refrigeration cycle device 1 including the heat exchanger 200 are the same as those of the heat exchanger 100, and thus detailed description thereof will be omitted.

[0226] The directions of the length direction DL, the width direction DW, and the stacking direction DS correspond to the directions indicated by the arrows in the drawings. The directions of the back, front, top, bottom, left, and right used in the following description correspond to the directions of the back, front, top, bottom, left, and right. Figure 7 , Figure 8 The direction indicated by the arrow in .

[0227] (1-1) Overall structure

[0228] The heat exchanger 200 is a heat exchanger including a plurality of first heat transfer plates 210, a plurality of second heat transfer plates 220, a first frame 230, a second frame 240, a first flow tube 250a, a first flow tube 250b, a second flow tube 260a, and a second flow tube 260b.

[0229] The heat exchanger 200 is provided with a first flow path 211 and a second flow path 221 therein. As will be described in detail later, the heat exchanger 200 has a fragile portion 290 that prevents the refrigerant flowing through the second flow path 221 from flowing into the first flow path 211 when water freezes.

[0230] The first heat transfer plate 210 and the second heat transfer plate 220 are metal plate-shaped members having the same rectangular shape. The first heat transfer plate 210 and the second heat transfer plate 220 have the same thickness. Figure 7 As shown, the outer shapes of the first heat transfer plate 210 , the second heat transfer plate 220 , the first frame 230 , and the second frame 240 are formed in a rectangular shape that is long in the first direction (the longitudinal direction DL).

[0231] The plurality of first heat transfer plates 210 and the plurality of second heat transfer plates 220 are alternately stacked. The number of each of the plurality of first heat transfer plates 210 and the plurality of second heat transfer plates 220 is not particularly limited and is appropriately set according to required performance.

[0232] (1-2) Detailed structure

[0233] (1-2-1) First heat transfer plate 210

[0234] The first heat transfer plate 210 is a corrugated fin having a corrugated cross section. In the present embodiment, the corrugation of the first heat transfer plate 210 is formed such that, in a plan view, the top 210t describes a herringbone pattern that is convex upward. The first heat transfer plate 210 forms a first flow path 211 and a second flow path 221 together with the second heat transfer plate 220 stacked adjacently. The first heat transfer plate 210 has a first joint area 210a, two first flow holes 210b, two first through holes 210c, a first surface 210sa, and a second surface 210sb.

[0235] The first joining region 210a is a region where the first heat transfer plate 210 and the second heat transfer plate 220 are joined to each other. The first joining region 210a is a band-shaped region in which an edge of a predetermined width is bent toward the front side.

[0236] The first flow hole 210b is a hole for allowing water to flow toward the first flow path 211. The first flow holes 210b are formed at the upper right side and the lower left side, respectively.

[0237] The first through hole 210c is a hole that allows the refrigerant to pass in the stacking direction DS. The first through hole 210c is formed on the upper left side and the lower right side.

[0238] The first surface 210sa is a surface on the front side of the first heat transfer plate 210. The first surface 210sa is a surface facing a second surface 220sb of a second heat transfer plate 220 described later when the first heat transfer plate 210 and the second heat transfer plate 220 are stacked.

[0239] The second surface 210sb is a surface on the back side of the first heat transfer plate 210. The second surface 210sb is a surface facing a first surface 220sa of a second heat transfer plate 220 described later when the first heat transfer plate 210 and the second heat transfer plate 220 are stacked.

[0240] The first heat transfer plate 210 is not limited, and is formed by, for example, press working.

[0241] It should be noted that regarding the shape of the first heat transfer plate 210, the "waveform" is not limited to Figure 8 The shape in which semicircular concavities and convexities are periodically arranged as shown may be a shape that changes periodically in a sinusoidal wave, a rectangular wave, a triangular wave, or the like. This also applies to the second heat transfer plate 220 .

[0242] (1-2-2) Second heat transfer plate 220

[0243] The second heat transfer plate 220 is a corrugated fin having a corrugated cross section. In the present embodiment, the corrugation of the second heat transfer plate 220 is formed such that, in a plan view, the top 220t describes a herringbone pattern that is convex downward. The second heat transfer plate 220 forms a first flow path 211 and a second flow path 221 together with the first heat transfer plate 210 stacked adjacently. The second heat transfer plate 220 has a second joint area 220a, two second flow holes 220b, two second through holes 220c, a first surface 220sa, and a second surface 220sb.

[0244] The second joining region 220a is a region where the first heat transfer plate 210 and the second heat transfer plate 220 are joined to each other. The second joining region 220a is a band-shaped region in which an edge of a predetermined width is bent toward the front side.

[0245] The second flow hole 220b is a hole for allowing the refrigerant to flow toward the second flow path 221. The second flow hole 220b is formed on the upper right side and the lower left side. The second flow hole 220b is formed at a position that overlaps and communicates with the first through hole 210c when the first heat transfer plate 210 and the second heat transfer plate 220 are stacked. The size and shape of the second flow hole 220b are the same as those of the first through hole 210c.

[0246] The second through hole 220c is a hole for passing water in the stacking direction DS. The second through hole 220c is formed on the upper left side and the lower right side. The second through hole 220c is formed at a position that overlaps and communicates with the first flow hole 210b when the first heat transfer plate 210 and the second heat transfer plate 220 are stacked. The size and shape of the second through hole 220c are the same as those of the first flow hole 210b.

[0247] The first surface 220sa is a surface on the front side of the second heat transfer plate 220. The first surface 220sa is a surface facing the second surface 210sb of the first heat transfer plate 210 when the first heat transfer plate 210 and the second heat transfer plate 220 are stacked.

[0248] The second surface 220sb is a surface on the back side of the second heat transfer plate 220. The second surface 220sb is a surface facing the first surface 210sa of the first heat transfer plate 210 when the first heat transfer plate 210 and the second heat transfer plate 220 are stacked.

[0249] The second heat transfer plate 220 is not limited, and is formed by, for example, press working.

[0250] (1-2-3) First Frame 230 and Second Frame 240

[0251] The first frame 230 and the second frame 240 are metal plate-shaped members that sandwich both ends of the alternately stacked plurality of first heat transfer plates 210 and second heat transfer plates 220 in the stacking direction DS.

[0252] (1-2-4) First Flow Tube 250a and First Flow Tube 250b

[0253] The first flow pipe 250a is a pipe for flowing water to the first flow path 211. The first flow pipe 250a is provided so as to penetrate the upper left side of the first frame 230 and communicate with the first flow path 211. More specifically, the first flow pipe 250a is formed so as to communicate with the first flow hole 210b and the second through hole 220c formed on the upper left side, which communicate with each other when the first heat transfer plate 210, the second heat transfer plate 220 and the first frame 230 are stacked.

[0254] The first flow pipe 250b is a pipe for flowing water to the first flow path 211. The first flow pipe 250a is provided so as to penetrate the lower right side of the first frame 230 and communicate with the first flow path 211. More specifically, the first flow pipe 250a is formed so as to communicate with the first flow hole 210b and the second through hole 220c formed on the lower right side, which communicate with each other when the first heat transfer plate 210, the second heat transfer plate 220 and the first frame 230 are stacked.

[0255] In addition, the first flow pipe 250a corresponds to the first flow pipe 170a of the heat exchanger 100. The first flow pipe 250b corresponds to the first flow pipe 170b of the heat exchanger 100.

[0256] (1-2-5) Second flow tube 260a and second flow tube 260b

[0257] The second flow pipe 260a is a pipe for circulating the refrigerant to the second flow path 221. The second flow pipe 260a is provided so as to penetrate the upper right side of the first frame 230 and communicate with the second flow path 221. More specifically, the second flow pipe 260a is formed so as to communicate with the second flow hole 220b and the first through hole 210c formed on the upper right side and communicate with each other when the first heat transfer plate 210, the second heat transfer plate 220 and the first frame 230 are stacked.

[0258] The second flow pipe 260b is a pipe for circulating the refrigerant to the second flow path 221. The second flow pipe 260a is provided so as to penetrate the lower left side of the first frame 230 and communicate with the second flow path 221. More specifically, the second flow pipe 260a is formed so as to communicate with the second flow hole 220b and the first through hole 210c formed on the lower left side, which communicate with each other when the first heat transfer plate 210, the second heat transfer plate 220 and the first frame 230 are stacked.

[0259] The second flow tube 260a corresponds to the second flow tube 180a of the heat exchanger 100. The second flow tube 260b corresponds to the second flow tube 180b of the heat exchanger 100.

[0260] (1-2-6) First flow path 211 and second flow path 221

[0261] The first flow path 211 and the second flow path 221 are alternately formed in the stacking direction DS by alternately stacking the first heat transfer plates 210 and the second heat transfer plates 220. More specifically, the first heat transfer plates 210 and the second heat transfer plates 220 are alternately stacked, so that the space where the first surface 210sa of the first heat transfer plate 210 and the second surface 220sb of the second heat transfer plate 220 face each other becomes the first flow path 211. In addition, the first heat transfer plates 210 and the second heat transfer plates 220 are alternately stacked, so that the space where the second surface 210sb of the first heat transfer plate 210 and the first surface 220sa of the second heat transfer plate 220 face each other becomes the first flow path 211.

[0262] In addition, the first flow path 211 corresponds to the first flow path 111 of the heat exchanger 100. The second flow path 221 corresponds to the second flow path 121 of the heat exchanger 100.

[0263] In the present embodiment, the first heat transfer plate 210 and the second heat transfer plate 220 are joined by brazing. More specifically, the first joining region 210a of the first heat transfer plate 210 and the second joining region 220a of the second heat transfer plate 220 are joined by brazing, and the top 210t of the first heat transfer plate 210 and the top 220t of the second heat transfer plate 220 are joined by brazing. Hereinafter, for convenience, the portion where the first surface 210sa side of the top 210t of the first heat transfer plate 210 and the second surface 220sb side of the top 220t of the second heat transfer plate 220 are joined is referred to as the third joining portion 210d, and the portion where the first surface 210sa side of the first joining region 210a and the second surface 220sb side of the second joining region 220a are joined is referred to as the fourth joining portion 210e.

[0264] (1-2-7) Vulnerable Department 290

[0265] The heat exchanger 200 has a weak portion 290 which is lower in strength than other portions and which ruptures due to volume expansion caused by freezing of water. The weak portion 290 is any one of the joints formed by the components forming the first flow path 211 being joined together. In the present embodiment, the third joint 210d and the fourth joint 210e function as the weak portion 290. In this case, the third joint 210d and the fourth joint 210e are preferably formed such that when the water expands in volume to a certain extent or more, the third joint 210d ruptures first, and then the fourth joint 210e ruptures.

[0266] In order to make the third joint portion 210d function as the fragile portion 290, the dimensions of the parts forming the first flow path 211 preferably satisfy the following relationship (Formula 7): Here, the width of the third joint portion 210d observed along the normal direction is set to bw3, and the wall thickness of the first heat transfer plate 210 and the second heat transfer plate is set to t.

[0267] 0.35×bw3<2×t…(Formula 7)

[0268] In addition, bw3 is, for example, 1 mm, and t is, for example, 2 mm.

[0269] In order for the fourth joint portion 210e to function as the fragile portion 290, the dimensions of the respective portions forming the first flow path 211 preferably satisfy the following relationship (Formula 8): Here, the width of the fourth joint portion 210e viewed along the normal direction is denoted by bsp4.

[0270] 0.35×(bsp4+bw3 / 2)<2×t…(Formula 8)

[0271] In addition, bsp4 is, for example, 1 mm.

[0272] (1-3) Flow of refrigerant and water

[0273] The water introduced from the first flow pipe 250a of the heat exchanger 200 flows into the first flow path 211 through the second through hole 220c and the first flow hole 210b on the upper side. The water flowing into the first flow path 211 flows toward the first flow hole 210b on the lower side in the first flow path 211. The water reaching the first flow hole 210b on the lower side passes through the second through hole 220c on the lower side and is led out from the first flow pipe 250b. In addition, the water introduced from the first flow pipe 250b of the heat exchanger 200 flows into the first flow path 211 through the second through hole 220c and the first flow hole 210b on the lower side. The water flowing into the first flow path 211 flows toward the first flow hole 210b on the upper side in the first flow path 211. The water reaching the first flow hole 210b on the upper side passes through the second through hole 220c on the upper side and is led out from the first flow pipe 250a. In either case, the water flowing in the first flow path 211 exchanges heat with the refrigerant in the adjacent second flow path 221 via the first heat transfer plate 210 or the second heat transfer plate 220 .

[0274] On the other hand, the refrigerant introduced from the second flow tube 260a of the heat exchanger 200 flows into the second flow path 221 through the first through hole 210c and the second flow hole 220b on the upper side. The refrigerant flowing into the second flow path 221 flows toward the second flow hole 220b on the lower side in the second flow path 221. The refrigerant reaching the second flow hole 220b on the lower side passes through the first through hole 210c on the lower side and is led out from the second flow tube 260b. In addition, the refrigerant introduced from the second flow tube 260b of the heat exchanger 200 flows into the second flow path 221 through the first through hole 210c and the second flow hole 220b on the lower side. The refrigerant flowing into the second flow path 221 flows toward the second flow hole 220b on the upper side in the second flow path 221. The refrigerant reaching the second flow hole 220b on the upper side passes through the first through hole 210c on the upper side and is led out from the second flow pipe 260a. In either case, the water flowing in the second flow path 221 exchanges heat with the water in the adjacent first flow path 211 via the first heat transfer plate 210 or the second heat transfer plate 220 to condense (during heating operation) or evaporate (during cooling operation and defrosting operation).

[0275] (2) Features

[0276] (2-1)

[0277] In the heat exchanger 200, the first flow path 211 has a first heat transfer plate 210 and a second heat transfer plate 220, a third joint 210d, and a fourth joint 210e. The first heat transfer plate 210 and the second heat transfer plate 220 are stacked on each other. The cross section of each of the first heat transfer plate 210 and the second heat transfer plate 220 is formed in a corrugated shape. The third joint is a portion where the tops 210t and 220t of the first heat transfer plate 210 and the second heat transfer plate 220 are joined. The fourth joint 210e is a portion where the end edges of the first heat transfer plate 210 and the second heat transfer plate 220 are joined.

[0278] (2-2)

[0279] The fragile portion 290 is the third joining portion 210d.

[0280] According to the heat exchanger 200, when water freezes and expands in volume, the third joint 210d formed by the components forming the first flow path 211 is broken earlier than other parts, thereby preventing the components or joints forming the second flow path 221 from breaking and causing refrigerant leakage.

[0281] (2-3)

[0282] The third joint portion 210d is joined by brazing. If the width of the third joint portion 210d viewed along the normal direction is set to bw3, and the wall thickness of the first heat transfer plate 210 and the second heat transfer plate 220 is set to t, they satisfy the following relationship:

[0283] 0.35×bw3<2×t…(Formula 7).

[0284] By forming the dimensions of each part so as to satisfy the above relationship, the stress generated in the first heat transfer plate 210 and the second heat transfer plate 220 when water freezes and expands in volume can be made smaller than the stress generated in the third joint portion 210d when water freezes and expands in volume. As a result, the third joint portion 210d, which is broken earlier than the first heat transfer plate 210 and the second heat transfer plate 220, can absorb the force generated by the volume expansion, so that the component or joint portion forming the second flow path 221 can be prevented from breaking and causing refrigerant leakage.

[0285] (2-4)

[0286] The fragile portion 290 is the fourth joining portion 210e.

[0287] According to the heat exchanger 200, when water freezes and expands in volume, the fourth joint 210e formed by the components forming the first flow path 211 is broken before other parts, thereby preventing the components or joints forming the second flow path 221 from breaking and causing refrigerant leakage.

[0288] (2-5)

[0289] The fourth joint portion 210e is joined by brazing. If the width of the fourth joint portion 210e observed along the normal direction is bsp4, the width of the third joint portion observed along the normal direction is bw3, and the wall thickness of the first heat transfer plate 210 and the second heat transfer plate 220 is t, they satisfy the following relationship:

[0290] 0.35×(bsp4+bw3 / 2)<2×t…(Equation 8).

[0291] By forming the dimensions of each part so as to satisfy the above relationship, the stress generated in the first heat transfer plate 210 and the second heat transfer plate 220 when water freezes and expands in volume can be made smaller than the stress generated in the fourth joint 210e when water freezes and expands in volume. As a result, the fourth joint 210e, which is broken before the first heat transfer plate 210 and the second heat transfer plate 220, can absorb the force generated by the volume expansion, so that the component or joint forming the second flow path 221 can be prevented from breaking and causing the refrigerant to leak.

[0292] (3) Modification

[0293] (3-1) Modification 2A

[0294] In the above embodiment, the third joint portion 210d and the fourth joint portion 210e function as the fragile portion 290, but as long as the component forming the second flow path 121 can be prevented from rupturing, it is also possible to form only one of the third joint portion 210d and the fourth joint portion 210e to function as the fragile portion 290.

[0295] (3-2) Modification 2B

[0296] In the above-described embodiment, the third joining portion 210d and the fourth joining portion 210e are joined by brazing, but the third joining portion 210d and the fourth joining portion 210e may be joined by diffusion bonding.

[0297] In the heat exchanger 200 of the modification 2B, similarly to the heat exchanger 200 of the second embodiment, when water freezes and expands in volume, the third joint 210d or the fourth joint 210e functioning as the fragile portion 290 ruptures earlier than other portions. Therefore, according to the heat exchanger 200 of the modification 2B, when water freezes and expands in volume, it is possible to suppress the leakage of refrigerant caused by rupture of the components or joints forming the second flow path 221.

[0298] In order for the third joint portion 210 d to function as the fragile portion 290 , the dimensions of each portion forming the first flow path 211 preferably satisfy the following relationship (Formula 9).

[0299] bw3<2×t…(Formula 9)

[0300] By forming the dimensions of each part so as to satisfy the above relationship, the stress generated in the first heat transfer plate 210 and the second heat transfer plate 220 when water freezes and expands in volume can be made smaller than the stress generated in the third joint portion 210d when water freezes and expands in volume. As a result, the third joint portion 210d, which is broken earlier than the first heat transfer plate 210 and the second heat transfer plate 220, can absorb the force generated by the volume expansion, so that the component or joint portion forming the second flow path 221 can be prevented from breaking and causing refrigerant leakage.

[0301] In order for the fourth joint portion 210 e to function as the fragile portion 290 , the dimensions of the respective portions forming the first flow path 211 preferably satisfy the following relationship (Formula 10).

[0302] (bsp4+bw3 / 2)<2×t…(Formula 10)

[0303] By forming the dimensions of each part so as to satisfy the above relationship, the stress generated in the first heat transfer plate 210 and the second heat transfer plate 220 when water freezes and expands in volume can be made smaller than the stress generated in the fourth joint 210e when water freezes and expands in volume. As a result, the fourth joint 210e, which is broken before the first heat transfer plate 210 and the second heat transfer plate 220, can absorb the force generated by the volume expansion, so that the component or joint forming the second flow path 221 can be prevented from breaking and causing the refrigerant to leak.

[0304] <Third embodiment>

[0305] (1) Heat exchanger

[0306] The heat exchanger 300 according to the third embodiment of the present disclosure is described below. The heat exchanger 100 and the heat exchanger 300 mainly differ in that the heat exchanger 100 forms a flow path by stacking inner fins and partition walls, whereas the heat exchanger 300 forms a flow path by stacking two heat transfer plates.

[0307] The refrigeration cycle device 1 may include a heat exchanger 300 instead of the heat exchanger 100. The structure and operation of the refrigeration cycle device 1 including the heat exchanger 300 are the same as those of the heat exchanger 100, and thus detailed description thereof will be omitted.

[0308] The directions of the length direction DL, the width direction DW, and the stacking direction DS correspond to the directions indicated by the arrows in the drawings. The directions of the back, front, top, bottom, left, and right used in the following description correspond to the directions of the back, front, top, bottom, left, and right. Fig. 9 , Fig.10 In addition, the same reference numerals are given to the features that are the same as or correspond to those in the first embodiment, and the description thereof is appropriately omitted.

[0309] (1-1) Overall structure

[0310] The heat exchanger 300 is a heat exchanger including a plurality of first heat transfer plates 310, a plurality of second heat transfer plates 320, a shell 160, a first flow tube 170a, a first flow tube 170b, a second flow tube 180a, and a second flow tube 180b. In other words, the heat exchanger 300 includes the first heat transfer plate 310 and the second heat transfer plate 320 instead of the first inner fin 110, the second inner fin 120, the partition wall 130, the first separation member 140, and the second separation member 150 of the heat exchanger 100. The heat exchanger 300 has a first flow path 311 for water to flow and a second flow path 321 for refrigerant to flow formed therein. As will be described in detail later, the heat exchanger 300 has a fragile portion 390 for preventing the refrigerant flowing in the second flow path 321 from flowing into the first flow path 311 when water freezes.

[0311] The first heat transfer plate 310 and the second heat transfer plate 320 are metal plate-shaped members having the same rectangular shape. Fig. 9 , Fig.10 As shown, the first heat transfer plate 310 and the second heat transfer plate 320 are formed in a rectangular shape that is long in the first direction (the longitudinal direction DL) similarly to the first inner fins 110 , the second inner fins 120 , and the partition walls 130 .

[0312] The first heat transfer plates 310 and the second heat transfer plates 320 are alternately stacked along the stacking direction DS and housed in the housing 160. The number of each of the first heat transfer plates 310 and the second heat transfer plates 320 is not particularly limited and is appropriately set according to required performance.

[0313] (1-2) Detailed structure

[0314] (1-2-1) First Heat Transfer Plate 310 and First Flow Path 311

[0315] The first heat transfer plate 310 is a plate-shaped member having a plurality of first flow paths 311 formed therein. The first flow paths 311 are formed to extend along the longitudinal direction DL when viewed from above. The plurality of first flow paths 311 are arranged at predetermined intervals in the width direction DW. In the present embodiment, the cross-sectional shape of the first flow path 311 cut by a plane perpendicular to the direction in which water flows is formed into a rectangular shape. The first flow path 311 is not limited, and may be formed, for example, by etching.

[0316] More specifically, the first heat transfer plate 310 is formed by stacking a plate member 310a and a plate member 310b in the stacking direction DS. The plate members 310a and 310b are formed by etching with grooves 311a and 311b that face each other during stacking to form the first flow path 311.

[0317] In the present embodiment, the plate-like member 310a and the plate-like member 310b are joined by brazing. Hereinafter, for convenience, the portion where the plate-like member 310a and the plate-like member 310b are joined and located between the adjacent first flow paths 311 when viewed from above is referred to as the fifth joint portion 310c. In addition, the portion where the plate-like member 310a and the plate-like member 310b are joined and located between the end portion in the width direction DW of the first heat transfer plate 310 and the first flow path 311 formed closest to the end portion is referred to as the sixth joint portion 310d. The fifth joint portion 310c and the sixth joint portion 310d are examples of joint portions.

[0318] In addition, the first flow path 311 corresponds to the first flow path 111 of the heat exchanger 100 .

[0319] (1-2-2) Second Heat Transfer Plate 320 and Second Flow Path 321

[0320] The second heat transfer plate 320 is a plate-shaped member having a plurality of second flow paths 321 formed therein. The second flow paths 321 are formed to extend along the width direction DW in a plan view. The plurality of second flow paths 321 are arranged at predetermined intervals in the longitudinal direction DL. The second flow paths 321 are not limited and may be formed, for example, by etching.

[0321] In addition, the second flow path 321 corresponds to the second flow path 121 of the heat exchanger 100 .

[0322] (1-2-3) Vulnerable Department 390

[0323] The heat exchanger 300 has a weak portion 390 which is weaker than other portions and which expands in volume due to freezing of water and thus breaks. In the present embodiment, the first heat transfer plate 310 which is a member forming the first flow path 311 functions as the weak portion 390 .

[0324] In order to make the first heat transfer plate 310 function as the fragile portion 390, the dimensions of each portion of the first heat transfer plate 310 preferably satisfy the following relationship (Formula 11). Here, the interval of the first flow path 311 formed in the first heat transfer plate 310 in the width direction DW is set to tw3, the sum of the interval tw3 and the width of the first flow path 311 in the width direction DW is set to Lw3, the interval between the first flow path 311 and the second flow path 321 in the stacking direction DS is set to tR3, and the height of the first flow path 311 in the stacking direction DS is set to hw3.

[0325] tw3 / (2×Lw3)<tR3 / hw3…(Formula 11)

[0326] In addition, tw3 is, for example, 0.15 mm, Lw3 is, for example, 2 mm, tR3 is, for example, 0.15 mm, and hw3 is, for example, 1 mm.

[0327] In order for the first heat transfer plate 310 to function as the fragile portion 390, the dimensions of the various portions forming the first heat transfer plate 310 preferably also satisfy the following relationship (Formula 12). Here, the interval in the width direction DW between the end portion of the first heat transfer plate 310 in the width direction DW and the first flow path 311 formed closest to the end portion is defined as Lsp3.

[0328] ((Lsp3+tw3 / 2) / Lw3)<tR3 / hw3…(Formula 12)

[0329] In addition, Lsp3 is, for example, 0.1 mm.

[0330] (2) Features

[0331] (2-1)

[0332] The heat exchanger 300 includes a first heat transfer plate 310 and a second heat transfer plate 320. The first heat transfer plate 310 has a first flow path 311 formed therein. The second heat transfer plate 320 has a second flow path 321 formed therein. The fragile portion 390 is the first heat transfer plate 310.

[0333] According to the heat exchanger 300, when water freezes and expands in volume, the first heat transfer plate 310 forming the first flow path 311 ruptures earlier than other portions, thereby preventing the second heat transfer plate 320 forming the second flow path 321 from rupturing and causing refrigerant leakage.

[0334] (3) Modification

[0335] (3-1) Modification 3A

[0336] In the above-mentioned embodiment, the component forming the first flow path 311 functions as the fragile portion 390, but the fragile portion 390 may also be a portion where the components forming the first flow path 311 are joined to each other. Specifically, the fragile portion 390 may also be the fifth joint portion 310c. In addition, the fragile portion 190 may also be the fifth joint portion 310c and the sixth joint portion 310d. In this case, it is preferably formed so that when the water expands in volume above a certain level, the fifth joint portion 310c is first broken, and then the sixth joint portion 310d is broken.

[0337] In the heat exchanger 300 of Modified Example 3A, when water freezes and expands in volume, the fifth joint 310c or the sixth joint 310d functioning as the fragile portion 390 ruptures earlier than other portions. Therefore, according to the heat exchanger 300 of Modified Example 3A, when water freezes and expands in volume, it is possible to suppress the refrigerant leakage caused by the rupture of the member (second heat transfer plate 320) forming the second flow path 321.

[0338] In order for the fifth joint portion 310c to function as the fragile portion 390, the dimensions of each portion of the first heat transfer plate 310 forming the first flow path 311 preferably satisfy the following relationship (Formula 13): Here, the width of the fifth joint portion 310c in a plan view is denoted by bw5.

[0339] 0.35×bw5 / (2×Lw3)<tR3 / hw3…(Formula 13)

[0340] In addition, bw5 is, for example, 0.035 mm.

[0341] By forming the dimensions of each part of the first heat transfer plate 310 to satisfy the above relationship, the stress generated between the first flow path 311 and the second flow path 321 when water freezes and expands in volume can be made smaller than the stress generated in the fifth joint portion 310c when water freezes and expands in volume. As a result, the fifth joint portion 310c, which is broken earlier than the first flow path 311 and the second flow path 321, can absorb the force generated by the volume expansion, so that the component forming the second flow path 321 can be prevented from breaking and causing refrigerant leakage.

[0342] In order for the sixth joint portion 310d to function as the fragile portion 390, the dimensions of each portion of the first heat transfer plate 310 forming the first flow path 311 preferably satisfy the following relationship (Formula 14): Here, the width of the sixth joint portion 310d in a plan view is denoted by bsp6.

[0343] 0.35×(2×bsp6+bw5) / Lw3<2×tR3 / hw3…(Formula 14)

[0344] In addition, bsp6 is, for example, 0.1 mm.

[0345] By forming the dimensions of each part of the first heat transfer plate 310 to satisfy the above relationship, the stress generated between the first flow path 311 and the second flow path 321 when water freezes and expands in volume can be made smaller than the stress generated in the sixth joint portion 310d when water freezes and expands in volume. As a result, the sixth joint portion 310d, which is broken earlier than the first flow path 311 and the second flow path 321, can absorb the force generated by the volume expansion, so that the component (second heat transfer plate 320) forming the second flow path 321 can be prevented from breaking and causing refrigerant leakage.

[0346] In the heat exchanger 300, the first heat transfer plate 310 is formed by laminating two plate-like members 310a and 310b having grooves 311a and 312b forming the first flow path 311. The fragile portion 390 is a portion where the two plate-like members 310a and 310b are joined.

[0347] According to the heat exchanger 300, when water freezes and expands in volume, the portion where the two plate-like parts 310a and 310b forming the first heat transfer plate 310 are joined (the fifth joining portion 310c and the sixth joining portion 310d) ruptures earlier than other portions, thereby preventing the second heat transfer plate 320 forming the second flow path from rupturing and causing refrigerant leakage.

[0348] (3-2) Modification 3B

[0349] In the above embodiment, the fifth joining portion 310c and the sixth joining portion 310d are joined by brazing, but the fifth joining portion 310c and the sixth joining portion 310d may be joined by diffusion bonding.

[0350] In the heat exchanger 300 of Modification 3B in which the fifth joint portion 310c and the sixth joint portion 310d are joined by diffusion joining, similarly to the heat exchanger 300 of Modification 3A, when water freezes and expands in volume, the fifth joint portion 310c or the sixth joint portion 310d functioning as the fragile portion 390 ruptures before the portion between the first flow path 311 and the second flow path 321. Therefore, according to the heat exchanger 300 of Modification 3B, when water freezes and expands in volume, it is possible to suppress the refrigerant leakage caused by the rupture of the member (second heat transfer plate 320) forming the second flow path 321.

[0351] In order for the fifth joint portion 310 c to function as the fragile portion 390 , the dimensions of each portion of the first heat transfer plate 310 forming the first flow path 311 preferably satisfy the following relationship (Formula 15).

[0352] bw5 / (2×Lw3)<tR3 / hw3…(Formula 15)

[0353] By forming the dimensions of each part so as to satisfy the above relationship, the stress generated between the first flow path 311 and the second flow path 321 when the water freezes and expands in volume can be made smaller than the stress generated in the fifth joint 310c when the water freezes and expands in volume. As a result, the fifth joint 310c, which is broken earlier than the first flow path 311 and the second flow path 321, can absorb the force generated by the volume expansion, so that the component or joint forming the second flow path 321 can be prevented from breaking and causing the refrigerant to leak.

[0354] In order for the sixth joining portion 310 d to function as the fragile portion 190 , the dimensions of each portion of the first heat transfer plate 310 forming the first flow path 111 preferably satisfy the following relationship (Expression 16).

[0355] (2×bsp6+bw5) / Lw3<2×tR3 / hw3…(Formula 16)

[0356] By forming the dimensions of each part so as to satisfy the above relationship, the stress generated between the first flow path 311 and the second flow path 321 when the water freezes and expands in volume can be made smaller than the stress generated in the sixth joint portion 310d when the water freezes and expands in volume. As a result, the sixth joint portion 310d, which is broken earlier than the first flow path 311 and the second flow path 321, can absorb the force generated by the volume expansion, so that the component or joint portion forming the second flow path 321 can be prevented from breaking and causing refrigerant leakage.

[0357] As mentioned above, although the embodiment of this disclosure is described, it should be understood that various changes in form and detailed structure can be made without departing from the spirit and scope of this disclosure described in the claims.

[0358] Description of symbols

[0359] 1: Refrigerant circulation device;

[0360] 100, 200, 300: heat exchanger;

[0361] 110: 1st inner fin;

[0362] 110c: first joint portion;

[0363] 110t: top;

[0364] 111, 211, 311: 1st flow path;

[0365] 130: Partition wall;

[0366] 140: Separation parts;

[0367] 140c: second joint portion;

[0368] 210, 310: first heat transfer plate;

[0369] 210d: third joint;

[0370] 210e: 4th joint;

[0371] 220, 320: second heat transfer plate;

[0372] 121, 221, 321: 2nd flow path;

[0373] 190, 290, 390: Vulnerable Department;

[0374] 310a, 310b: plate-shaped components;

[0375] 310c: 5th joint;

[0376] 310d: 6th joint;

[0377] 311a, 311b: slots.

[0378] Prior art literature

[0379] Patent Literature

[0380] Patent Document 1: Japanese Patent Application Laid-Open No. 10-132476

Claims

1. A heat exchanger (100, 200, 300) for performing heat exchange between water and a refrigerant, wherein: The heat exchanger (100, 200, 300) comprises: a first flow path (111, 211, 311) for the water to flow; and a second flow path (121, 221, 321) through which the refrigerant flows, Any of the components (110, 140) other than the partition wall (130) that forms the first flow path and separates the first flow path from the second flow path, or any of the joints (110c, 140c, 210d, 210e) formed by joining the components forming the first flow path together, functions as a fragile portion (190, 290, 390) having a lower strength than other components forming the first flow path.

2. The heat exchanger according to claim 1, wherein: The first flow path is formed using the following components: two of the partition walls; an inner fin (110) having a corrugated cross section and stacked between the two partition walls; and A separation component (140) is arranged at the end edges of the two partition walls to separate the two partition walls.

3. The heat exchanger according to claim 2, wherein: The fragile portion is the inner fin.

4. The heat exchanger according to claim 3, wherein: The wall thickness of the inner fin is set to tw, The distance between the tops (110t) of the inner fins connected to the same partition wall is Lw. The wall thickness of the partition wall is tR, The height of the inner fin in the stacking direction is hw, Then they satisfy the following relationship: tw / Lw<tR / hw.

5. The heat exchanger according to claim 2, wherein: The fragile portion is the separation member.

6. The heat exchanger according to claim 5, wherein: The width of the separation component in a top view is set to Lsp, The wall thickness of the inner fin is set to tw, The distance between the tops of the inner fins connected to the same partition wall is Lw. The wall thickness of the partition wall is tR, The height of the inner fin in the stacking direction is defined as hw. Then they satisfy the following relationship: ((Lsp+tw) / Lw)<tR / hw.

7. The heat exchanger according to claim 1, wherein: The first flow path is formed using the following components: two of the partition walls; an inner fin (110) having a corrugated cross section and stacked between the two partition walls; and A separation component (140) is arranged at the end edges of the two partition walls to separate the two partition walls. The heat exchanger comprises: A first joint portion (110c) formed by joining the partition wall and the top of the inner fin; and A second joint portion (140c) formed by joining the partition wall and the separation member.

8. The heat exchanger according to claim 7, wherein: The fragile portion is the first joining portion.

9. The heat exchanger according to claim 8, wherein: The first joint portion is joined by brazing, The width of the first joint is defined as bw1. The distance between the tops of the inner fins connected to the same partition wall is Lw. The wall thickness of the partition wall is tR, The height of the inner fin in the stacking direction is defined as hw. Then the following relationship is satisfied: 0.35×bw1 / (2×Lw)<tR / hw.

10. The heat exchanger according to claim 8, wherein: The first bonding portion is bonded by diffusion bonding, The width of the first joint is defined as bw1. The distance between the tops of the inner fins connected to the same partition wall is Lw. The wall thickness of the partition wall is tR, The height of the inner fin in the stacking direction is defined as hw. Then they satisfy the following relationship: bw1 / (2×Lw)<tR / hw.

11. The heat exchanger according to claim 7, wherein: The fragile portion is the second joining portion.

12. The heat exchanger according to claim 11, wherein The second joint portion is joined by brazing, The width of the second joint is set to bsp2, The width of the first joint is defined as bw1. The distance between the tops of the inner fins connected to the same partition wall is Lw. The wall thickness of the partition wall is tR, The height of the inner fin in the stacking direction is defined as hw. Then they satisfy the following relationship: 0.35×(2×bsp2+bw1) / Lw<2×tR / hw.

13. The heat exchanger according to claim 11, wherein: The second bonding portion is bonded by diffusion bonding, The width of the second joint is set to bsp2, The width of the first joint is defined as bw1. The distance between the tops of the inner fins connected to the same partition wall is Lw. The wall thickness of the partition wall is tR, The height of the inner fin in the stacking direction is defined as hw. Then they satisfy the following relationship: (2×bsp2+bw1) / Lw<2×tR / hw.

14. The heat exchanger according to claim 1, wherein: The first flow path is formed by using two heat transfer plates (210, 220) stacked on each other and having a corrugated cross section. The heat exchanger has: a third joint portion (210d) formed by joining the tops of the two heat transfer plates; and A fourth joint (210e) formed by joining the end edges of the two heat transfer plates.

15. The heat exchanger according to claim 14, wherein: The fragile portion is the third joining portion.

16. The heat exchanger according to claim 15, wherein: The third joint portion is joined by brazing, The width of the third joint portion when viewed along the normal direction is denoted as bw3, and the thickness of the heat transfer plate is denoted as t. Then they satisfy the following relationship: 0.35×bw3<2×t.

17. The heat exchanger according to claim 15, wherein: The third bonding portion is bonded by diffusion bonding, The width of the third joint portion when viewed along the normal direction is denoted as bw3, and the thickness of the heat transfer plate is denoted as t. Then they satisfy the following relationship: bw3<2×t.

18. The heat exchanger according to claim 14, wherein: The fragile portion is the fourth joining portion.

19. The heat exchanger according to claim 18, wherein: The fourth joint portion is joined by brazing, The width of the fourth joint portion when viewed along the normal direction is denoted as bsp4, the width of the third joint portion when viewed along the normal direction is denoted as bw3, the wall thickness of the heat transfer plate is denoted as t, Then they satisfy the following relationship: 0.35×(bsp4+bw3 / 2)<2×t.

20. The heat exchanger according to claim 18, wherein The fourth bonding portion is bonded by diffusion bonding, The width of the fourth joint portion when viewed along the normal direction is denoted as bsp4, the width of the third joint portion when viewed along the normal direction is denoted as bw3, the wall thickness of the heat transfer plate is denoted as t, Then they satisfy the following relationship: (bsp4+bw3 / 2)<2×t.

21. The heat exchanger according to claim 1, wherein: The heat exchanger has: a first heat transfer plate (310) having the first flow path formed therein; and a second heat transfer plate (320) having the second flow path formed therein; The fragile portion is the first heat transfer plate.

22. The heat exchanger according to claim 21, wherein The first heat transfer plate is formed by stacking two plate-like members (310a, 310b) having grooves (311a, 311b), wherein the grooves (311a, 311b) form the first flow path. The fragile portion is a portion (310c, 310d) where the two plate-like members are joined.

23. The heat exchanger according to any one of claims 1 to 22, wherein: The refrigerant is flammable or toxic.

24. The heat exchanger according to any one of claims 1 to 23, wherein: The fragile portion is formed to have a strength sufficient to break when the water freezes.

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