JPWO2016185689A1 - Air conditioning and hot water supply system - Google Patents

Abstract

An air conditioning and hot water supply system according to the present invention includes a first refrigeration cycle including a hot water supply compressor, a hot water supply heat exchanger, and a cascade heat exchanger, an air conditioning compressor, an outdoor heat exchanger, an indoor heat exchanger, and a cascade. And a second refrigeration cycle including a heat exchanger. The amount of hot water supply refrigerant enclosed in the first refrigeration cycle is such that the saturated liquid pressure of the mixed refrigerant when the hot water supply refrigerant is mixed with the air conditioning refrigerant is equal to or lower than the upper limit pressure of the air conditioning compressor. . Thereby, the reliability of a 2nd freezing cycle can be improved, without impairing the durability of a compressor.

Description

  The present invention includes an air conditioning hot water supply that includes a refrigeration cycle in which an air conditioning refrigerant circulates and a refrigeration cycle in which a hot water supply refrigerant circulates, and performs heat exchange between the air conditioning refrigerant and the hot water supply refrigerant via a cascade heat exchanger. About the system.

  2. Description of the Related Art Conventionally, air conditioning and hot water supply systems that can simultaneously supply hot and cold heat necessary for cooling, heating, and hot water supply are known.

  In such an air conditioning and hot water supply system, the refrigeration cycle through which the air conditioning refrigerant circulates and the refrigeration cycle through which the hot water supply refrigerant circulates are thermally connected in a cascade heat exchanger to form a so-called dual refrigeration cycle. .

  As a conventional air-conditioning hot water supply system, for example, a hot water supply apparatus including a hot water supply refrigerant circuit that is connected to a compressor, a first heat exchanger, an expansion mechanism, and a second heat exchanger and is filled with carbon dioxide refrigerant is proposed. Has been. In such an air-conditioning hot-water supply system, it has been proposed that the first heat exchanger is a heat exchanger for generating hot water, the second heat exchanger is a cascade heat exchanger, and the hot water supply device is unitized (for example, Patent Document 1).

  In Patent Document 1, two kinds of refrigerants such as a hot water supply refrigerant and an air conditioning refrigerant are circulated in the cascade heat exchanger. For this reason, if the wall surface in the cascade heat exchanger that separates the two types of refrigerant flow paths is damaged due to aging degradation or collision of foreign matter due to corrosion or the like, There is a problem that the refrigerant for air conditioning is mixed.

  In particular, when a carbon dioxide refrigerant is used as the hot water supply refrigerant, the carbon dioxide refrigerant is higher in pressure than R410A, R407C, and R32, which are generally used as air conditioning refrigerants. It flows into the refrigeration cycle side where the air-conditioning refrigerant circulates. As for the physical properties of the mixed refrigerant in which the air-conditioning refrigerant and the carbon dioxide refrigerant are mixed, the saturated liquid pressure at the same temperature is significantly increased as compared with the original air-conditioning refrigerant.

  Generally, in an air conditioning compressor, a pressure 1.5 times higher than the pressure at 50 ° C., which is a condensation temperature operated in a normal air conditioning system, is set as the upper limit pressure for use of the air conditioning compressor.

  When the carbon dioxide refrigerant flows into the refrigeration cycle in which the air-conditioning refrigerant circulates, the saturated liquid pressure of the refrigerant becomes high, and there is a possibility that the operation exceeds the use upper limit pressure of the air-conditioning compressor. This has a problem of impairing the durability of the air conditioning compressor.

JP 2004-132647 A (Japanese Patent No. 3925383)

  The present invention has been made in view of the above points, and even when a hot water supply refrigerant is mixed in a refrigeration cycle for air conditioning, the air conditioning can be operated within a range not more than the upper limit pressure of the air conditioning compressor. An object is to provide a hot water supply system. Thereby, the reliability of a 2nd freezing cycle can be improved, without impairing the durability of a compressor.

  The air conditioning hot water supply system of the present invention heats the hot water supply compressor that compresses the hot water supply refrigerant, the hot water supply heat exchanger that exchanges heat between the hot water supply refrigerant and the hot water supply heat medium, the hot water supply refrigerant, and the air conditioning refrigerant. A first refrigeration cycle comprising: a cascade heat exchanger to be exchanged; an air conditioning compressor that compresses an air conditioning refrigerant; an outdoor heat exchanger that exchanges heat between the air conditioning refrigerant and outdoor air; and an air conditioning refrigerant; A second refrigeration cycle including an indoor heat exchanger for exchanging heat with indoor air and a cascade heat exchanger. The amount of hot water supply refrigerant enclosed in the first refrigeration cycle is such that the saturated liquid pressure of the mixed refrigerant when the hot water supply refrigerant is mixed with the air conditioning refrigerant is equal to or lower than the upper limit pressure of the air conditioning compressor. .

  In the above configuration, the hot water supply refrigerant is a carbon dioxide refrigerant, the air conditioning refrigerant is any one of R410A, R32, and R407C, and the amount of hot water supply refrigerant enclosed in the first refrigeration cycle is Further, it may be 24.5 wt% or less of the amount of air-conditioning refrigerant sealed in the second refrigeration cycle.

  In the above configuration, the cascade heat exchanger may be either a plate heat exchanger or a shell-and-tube heat exchanger.

  In the above configuration, the hot water supply heat exchanger may be either a plate heat exchanger or a shell and tube heat exchanger.

  According to the air conditioning and hot water supply system of the present invention, the amount of the hot water supply refrigerant sealed in the first refrigeration cycle is equal to the saturated liquid pressure of the mixed refrigerant when the hot water supply refrigerant is mixed into the air conditioning refrigerant. The amount is less than the upper limit of use pressure. Thereby, even when the hot water supply refrigerant sealed in the first refrigeration cycle flows into the second refrigeration cycle, the operating pressure of the second refrigeration cycle is set to be equal to that of the air conditioning compressor installed in the second refrigeration cycle. It can be made below the upper limit of use pressure. As a result, the reliability of the second refrigeration cycle can be improved without impairing the durability of the air conditioning compressor.

FIG. 1 is a configuration diagram of a refrigeration cycle showing an embodiment of an air conditioning and hot water supply system according to the present invention. FIG. 2 is a plan view showing the internal structure of the heat generation unit in the air conditioning and hot water supply system of the present embodiment. FIG. 3 is a front view showing the internal structure of the heat generation unit in the air conditioning and hot water supply system of the present embodiment. FIG. 4 is a conceptual diagram showing a structure in a state where the cascade heat exchanger is disassembled. FIG. 5 is a graph showing the relationship between the mixing ratio of the air conditioning refrigerant R410A and the carbon dioxide refrigerant and the pressure. FIG. 6 is a Mollier chart of R410A and a mixed refrigerant in which R410A and a carbon dioxide refrigerant are mixed. FIG. 7 is a graph showing the relationship between the mixing ratio of the air conditioning refrigerant R32 and the carbon dioxide refrigerant and the pressure. FIG. 8 is a graph showing the relationship between the mixing ratio of the air conditioning refrigerant R407C and the carbon dioxide refrigerant and the pressure.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a cycle configuration diagram of an air conditioning and hot water supply system according to an embodiment of the present invention.

  The air conditioning hot water supply system shown in FIG. 1 includes an outdoor unit 10, an indoor unit 30, and a heat generation unit 40. In the present embodiment, two indoor units 30 and one heat generation unit 40 are connected to one outdoor unit 10. Note that the refrigeration cycle configuration is not limited to that shown in FIG. For example, two or more outdoor units 10, one or three indoor units 30, and two or more heat generation units 40 can be connected in parallel.

  The outdoor unit 10, the indoor unit 30, and the heat generation unit 40 are connected by a pipe through which air-conditioning refrigerant flows.

  The outdoor unit 10 and the indoor unit 30 include a gas pipe 25 through which high-temperature and high-pressure gasified air-conditioning refrigerant flows, a suction pipe 26 through which low-pressure air-conditioning refrigerant flows, and a liquid pipe 27 through which high-pressure liquefied air-conditioning refrigerant flows. And connected with. When there are two indoor units 30 as shown in FIG. 1, the indoor units 30 are connected in parallel to the three pipes. On the other hand, the outdoor unit 10 and the heat generation unit 40 are connected in parallel to the piping as in the indoor unit 30, but are connected by a gas pipe 25 and a liquid pipe 27.

  The outdoor unit 10 includes an air conditioning compressor 11 that compresses the air conditioning refrigerant. An accumulator 12 for supplying a gas refrigerant to the air conditioning compressor 11 is connected to the suction side of the air conditioning compressor 11. An oil separator 13 is connected to the discharge side of the air conditioning compressor 11 for separating the refrigerating machine oil contained in the discharged air-conditioning refrigerant. The refrigerating machine oil separated by the oil separator 13 is returned to the air conditioning compressor 11 by the oil return pipe 14. The communication of the oil return pipe 14 is controlled by opening and closing the oil return pipe opening / closing valve 15.

  The outdoor unit 10 includes an outdoor heat exchanger 16. In the vicinity of the outdoor heat exchanger 16, an outdoor blower fan 17 that supplies air around the outdoor unit 10 to the outdoor heat exchanger 16 is provided. The outdoor heat exchanger 16 is configured to exchange heat between the air sent by the outdoor blower fan 17 and the air-conditioning refrigerant. Generally, heat exchange of a fin-tube type or a microtube type is performed. The vessel is applied.

  The outdoor unit 10 includes an outdoor refrigerant flow rate adjustment valve 18 that adjusts the flow rate of the air-conditioning refrigerant supplied to the outdoor heat exchanger 16, an outdoor gas pipe opening / closing valve 19 that controls the flow rate of the air-conditioning refrigerant in the gas pipe 25, and a suction unit. An outdoor suction pipe opening / closing valve 20 for controlling the flow rate of the air conditioning refrigerant in the pipe 26 is provided.

  The indoor unit 30 adjusts the flow rate of the indoor heat exchanger 31, the indoor blower fan 32 that supplies air around the indoor unit 30 to the indoor heat exchanger 31, and the air conditioning refrigerant that is supplied to the indoor heat exchanger 31. And an indoor refrigerant flow rate adjustment valve 33. The indoor heat exchanger 31 is configured to exchange heat between the air sent by the indoor fan 32 and the air-conditioning refrigerant. Generally, a fin-tube or microtube heat exchanger is used. Applied.

  The indoor unit 30 includes an indoor gas pipe opening / closing valve 34 that controls the flow of air-conditioning refrigerant with the gas pipe 25 and an indoor suction pipe opening / closing valve that controls the flow of air-conditioning refrigerant with the suction pipe 26. 35.

  Air conditioning compressor 11, accumulator 12, oil separator 13, outdoor heat exchanger 16, outdoor refrigerant flow rate adjustment valve 18, outdoor gas pipe on / off valve 19, outdoor suction pipe on / off valve 20, and indoor heat The exchanger 31, the indoor refrigerant flow rate adjustment valve 33, the indoor gas pipe opening / closing valve 34, and the indoor intake pipe opening / closing valve 35 constitute a second refrigeration cycle.

  The heat generation unit 40 adjusts the flow rate of the hot water supply refrigerant, the hot water supply compressor 41 that compresses the hot water supply refrigerant, the hot water supply heat exchanger 42 that exchanges heat with the hot water refrigerant and the heat medium mainly composed of water, and the hot water supply refrigerant. The hot water supply refrigerant flow rate adjusting valve 43 is provided.

  Furthermore, the heat generation unit 40 adjusts the flow rate of the air conditioning refrigerant supplied to the cascade heat exchanger 44 and the cascade heat exchanger 44 that exchanges heat between the air conditioning refrigerant and the hot water supply refrigerant supplied from the gas pipe 25. A heat generation unit refrigerant flow rate adjustment valve 45 and a heat medium pump 46 for supplying a heat medium to the hot water supply heat exchanger 42 are provided.

  A hot water supply compressor 41, a hot water supply heat exchanger 42, a hot water supply refrigerant flow rate adjustment valve 43, a cascade heat exchanger 44, a heat generation unit refrigerant flow rate adjustment valve 45, and a heat medium pump 46, A refrigeration cycle is configured.

  In general, tap water is used as the heat medium, but in a cold district, an antifreeze solution in which a predetermined amount of ethylene glycol or alcohol is dissolved in water may be used.

  The heat medium boiled up to 70 to 90 ° C. by the hot water supply heat exchanger 42 is stored in a hot water storage tank (not shown). When the heat medium is drinking water, it is used directly for hot water supply. On the other hand, when the heat medium is not drinking water such as antifreeze, it is supplied to a radiator or the like installed indoors and used for heating, or used for hot water supply by transferring heat to drinking water in a hot water storage tank.

  Next, the internal structure of the heat generation unit 40 in this embodiment will be described.

  FIG. 2 is a plan view showing the internal structure of the heat generation unit 40 in the present embodiment. FIG. 3 is a front view showing the internal structure of the heat generation unit 40.

  The heat generation unit 40 includes a refrigeration cycle formed by a hot water supply compressor 41, a hot water supply heat exchanger 42, a hot water supply refrigerant flow rate adjustment valve 43, and a cascade heat exchanger 44, a heat generation unit refrigerant flow rate adjustment valve 45, The heat medium pump 46 is housed in the casing 50.

  In the present embodiment, for example, a double-pipe heat exchanger is used as the hot water supply heat exchanger 42. The double tube heat exchanger is a heat exchanger formed by inserting one or more tubes (inner tubes) into a tube (outer tube) having a substantially circular cross section. When there are a plurality of inner tubes, the inner tubes are inserted into the outer tube by spiraling. When the carbon dioxide refrigerant is used as the hot water supply refrigerant, the carbon dioxide refrigerant flows through the inner pipe of the hot water supply heat exchanger 42 and the heat medium flows between the outer pipe and the inner pipe.

  In addition, a copper pipe with high heat conduction performance is often used as the material of the double pipe heat exchanger.

  Moreover, for the hot water supply heat exchanger 42, for example, a plate heat exchanger, a shell and tube heat exchanger, or the like may be used. The cascade heat exchanger 44 is, for example, a plate heat exchanger or a shell and tube heat exchanger.

  The heat exchange capacity of the double pipe heat exchanger is proportional to the length of the double pipe. Therefore, the double-pipe heat exchanger is formed by winding a double pipe in order to secure the maximum heat exchange capability within a limited installation volume. When installing a double-pipe heat exchanger, make sure that the double pipe is as horizontal as possible in order to prevent air from accumulating in the part where the heat medium passes through the double pipe and causing a significant decline in heat exchange performance. To do.

  As shown in FIGS. 2 and 3, the hot water supply compressor 41 is fixed to the bottom plate member 51 of the casing 50 by a fixing member 67 with a vibration isolating member 60 such as rubber interposed therebetween.

  Further, the hot water supply heat exchanger 42 is also fixed to the bottom plate member 51 via the vibration isolator 61, and the cascade heat exchanger 44 is fixed to the upper surface of the hot water supply heat exchanger.

  Each of the hot water supply heat exchanger 42 and the cascade heat exchanger 44 shown in FIGS. 2 and 3 includes a heat insulating material such as polystyrene foam or thick felt, and a component surrounding the heat insulating material. In particular, since the heat exchanger for hot water supply is assumed to be deformed by the weight of the cascade heat exchanger 44 installed at the upper part, it is surrounded by a high-strength iron plate and the surface of the heat insulator is protected.

  The cascade heat exchanger 44 is not necessarily in contact with the components surrounding the hot water supply heat exchanger 42. In this case, the cascade heat exchanger 44 and the surrounding heat insulating material are surrounded by a component having sufficient strength to support the weight of the cascade heat exchanger 44 and the surrounding heat insulating material, and then the heat generating unit. 40 side plate members 52 are fixed.

  Further, the heat medium pump 46 is fixed to a side plate member 53 on the back side of the casing 50 as shown in FIG. The lower end surface of the heat medium pump 46 is installed at a position lower than the lower end surface of the cascade heat exchanger 44.

  Further, as shown in FIGS. 2 and 3, the bottom plate member 51 includes a drain outlet 62 in a region where the hot water supply heat exchanger 42 and the heat medium pump 46 project onto the bottom plate member 51 when viewed from above. Is provided. The upper surface of the bottom plate member 51 is appropriately inclined toward the drain port 62 so that water can be quickly discharged from the drain port 62 to the outside of the heat generation unit 40.

  The flow of the heat medium in the heat medium pipes 63, 64, 65 is generated by driving the heat medium pump 46. The heat medium flowing into the heat generating unit 40 flows into the heat medium pump 46 via the heat medium pipe 63 and is sent to the heat medium pipe 64. Further, the heat medium enters the hot water supply heat exchanger 42, is heated by the hot water supply refrigerant and reaches a high temperature of 70 to 90 ° C., and then is sent to the outside of the heat generation unit 40 via the heat medium pipe 65. The

  Most of the heat medium pipes 63, 64, 65 are made of copper pipes with good workability, but resin materials are also used. On the other hand, a resin material is often used for the heat medium suction part and the discharge part of the heat medium pump 46. Moreover, as mentioned above, copper is often used for the hot water supply heat exchanger 42 which is a double-pipe heat exchanger, and the connection port is also a copper pipe.

  In this way, in the path through which the heat medium flows (heat medium pipe 63 → heat medium pump 46 → heat medium pipe 64 → heat exchanger for hot water supply 42 → heat medium pipe 65), resin material and copper are mixed and different materials. There is a connection between them. A sealing material (not shown) is sandwiched and fixed in the heat medium pump connection portion so that there is no leakage of the heat medium.

  Note that R410A, R32, R407C, and the like, which are refrigerants generally used for home air conditioners and building air conditioners, are used as the air conditioning refrigerant, and carbon dioxide refrigerant is used as the hot water supply refrigerant.

  Further, in the present embodiment, the amount of hot water supply refrigerant sealed in the first refrigeration cycle is such that the saturated liquid pressure of the mixed refrigerant when the hot water supply refrigerant is mixed with the air conditioning refrigerant is equal to that of the air conditioning compressor 11. The amount is below the upper limit of use pressure. Specifically, when a carbon dioxide refrigerant is used as the hot water supply refrigerant and any one of R410A, R32, and R407C is used as the air conditioning refrigerant, the hot water supply refrigerant sealed in the first refrigeration cycle is used. The amount enclosed is 24.5 wt% or less of the amount of air-conditioning refrigerant enclosed in the second refrigeration cycle.

  Here, in the structure of the cascade heat exchanger 44 that thermally connects the first refrigeration cycle and the second refrigeration cycle, the flow paths of the respective refrigerants are separated so that the air conditioning refrigerant and the hot water supply refrigerant do not mix. ing.

  FIG. 4 is a conceptual diagram showing the structure of the cascade heat exchanger 44 in an exploded state.

  As shown in FIG. 4, the cascade heat exchanger 44 includes a plurality of heat transfer plates 70 formed in a thin box shape with one side open. Each heat transfer plate 70 is overlapped and brought into close contact by brazing or the like, so that a refrigerant flow path space 71 is formed between each overlapped heat transfer plate 70.

  End frames 72 are attached to both ends of each heat transfer plate 70. Nozzles 73 are respectively provided at the four corners of one end frame 72. One nozzle 73 on the lower side of the end frame 72 is an air-conditioning refrigerant inlet 74a, and one nozzle 73 on the upper side is an air-conditioning refrigerant outlet 74b. On the other hand, the nozzle 73 on the other side on the upper side of the end frame 72 is an inlet 74c for the hot water supply refrigerant, and the nozzle 73 on the other side on the lower side is an outlet 74d for the hot water supply refrigerant.

  Each nozzle 73 is connected to a pipe 75 that passes through four corners of each heat transfer plate 70. An air conditioning refrigerant inflow pipe 75a is connected to the air conditioning refrigerant inlet 74a, and an air conditioning refrigerant outlet pipe 75b is connected to the air conditioning refrigerant outlet 74b. A hot water supply refrigerant inflow pipe 75c is connected to the hot water supply refrigerant inlet 74c, and a hot water supply refrigerant outlet pipe 75d is connected to the hot water supply refrigerant outlet 74d.

  The inflow pipe 75a and the outflow pipe 75b of the air conditioning refrigerant are communicated with every other refrigerant flow space 71 in the refrigerant flow space 71, respectively. Thereby, as shown by the solid line arrow in FIG. 4, after the air conditioning refrigerant that has flowed into the cascade heat exchanger 44 from the inflow port 74 a flows into the refrigerant flow path space 71 that communicates with the inflow pipe 75 a, It flows out of the cascade heat exchanger 44 from the outlet 74b through the outlet pipe b.

  In addition, the inflow pipe 75 c and the outflow pipe 75 d of the hot water supply refrigerant are in communication with every other refrigerant flow path space 71 in the refrigerant flow path space 71. Thereby, as indicated by the broken line arrows in FIG. 4, the hot water supply refrigerant that has flowed into the cascade heat exchanger 44 from the inflow port 74c flows into the refrigerant flow path space 71 that communicates with each other through the inflow pipe 75c. It flows out of the cascade heat exchanger 44 from the outlet 74d through the outlet pipe 75d.

  Thus, since the refrigerant flow path space 71 in which the air conditioning refrigerant flows and the refrigerant flow path space 71 in which the hot water supply refrigerant flows are alternately arranged, the hot water supply refrigerant and the air conditioning refrigerant are transferred to the heat transfer plate 70. It is possible to exchange heat with each other through the wall surface.

  Since the cascade heat exchanger 44 is configured as described above, in the unlikely event that the heat transfer plate 70 or the pipe 75 is damaged due to aged deterioration or collision of foreign matter due to corrosion or the like, The hot water supply refrigerant will be mixed through the damaged part. In this case, the saturated refrigerant pressure at the same temperature of the mixed refrigerant obtained by mixing the air conditioning refrigerant and the carbon dioxide refrigerant that is the hot water supply refrigerant is significantly higher than that of the original air conditioning refrigerant.

  FIG. 5 is a graph showing the relationship between the mixing ratio of R410A generally used as an air conditioning refrigerant and a carbon dioxide refrigerant and the pressure.

  As shown in FIG. 5, the saturated liquid pressure of R410A tends to increase as the mixing ratio with carbon dioxide increases in any of 30 ° C., 40 ° C., and 50 ° C. The saturated liquid pressure at 50 ° C., which is the condensation temperature operated in a normal air conditioning system, is 3.1 MPa in the case of R410A alone, but R410A and carbon dioxide refrigerant are mixed at 1: 1. The saturated liquid pressure of the mixed refrigerant thus obtained is 6.7 MPa.

  In an ordinary air conditioning system, the upper limit pressure that can ensure the reliability of the compressor for R410A used for air conditioning, that is, the upper limit pressure for use is set to a pressure 1.5 times higher than the pressure during normal operation. Is common. That is, when the saturated liquid pressure of R410A at 50 ° C. is 3.1 MPa, 4.6 MPa calculated as 1.5 times higher pressure is set as the use upper limit pressure.

  Therefore, in order to ensure the reliability of the compressor for R410A, the compressor needs to be operated at a pressure lower than the use upper limit pressure.

  However, when a mixed refrigerant in which R410A and carbon dioxide refrigerant are mixed at 1: 1 is operated so as to have a condensation temperature of 50 ° C. in a refrigeration cycle for air conditioning, the saturated liquid pressure becomes 6.7 MPa. There is a problem that the operation exceeds the upper limit pressure of 4.6 MPa of the compressor for R410A used for air conditioning.

  Here, as shown in FIG. 5, when the mixing ratio of the carbon dioxide refrigerant to R410A is 24.5 wt%, the saturated liquid pressure at 50 ° C. of the mixed refrigerant of R410A and the carbon dioxide refrigerant is 4.6 MPa. On the other hand, when the mixing ratio of the carbon dioxide refrigerant to R410A exceeds 24.5 wt%, the saturated liquid pressure at 50 ° C. of the mixed refrigerant of R410A and carbon dioxide refrigerant exceeds 4.6 MPa.

  FIG. 6 shows a Mollier chart of a mixed refrigerant in which R410A and a carbon dioxide refrigerant are mixed, and a Mollier chart of R410A. In FIG. 6, the curves shown by the solid lines are the saturated liquid line and saturated gas line of R410A alone, respectively. Moreover, in FIG. 6, the curve shown with a broken line is the saturated liquid line and saturated gas line of the mixed refrigerant which mixed R410A and the carbon dioxide refrigerant in the ratio of 100: 24.5 wt%. Moreover, the isotherm by a solid line is a 50 degreeC isotherm of R410A simple substance, and the isotherm by a broken line is a 50 degreeC isotherm of a mixed refrigerant.

  As shown in FIGS. 5 and 6, when the mixing ratio of the carbon dioxide refrigerant to R410A is 24.5 wt%, the saturated liquid pressure at 50 ° C. of the mixed refrigerant of R410A and carbon dioxide refrigerant is 4.6 MPa. This is a value 1.5 times higher than the saturated liquid pressure at 50 ° C. of R410A alone, and is equal to the upper limit pressure of the R410A compressor used for air conditioning.

  On the other hand, when the mixing ratio of the carbon dioxide refrigerant to R410A exceeds 24.5 wt%, the saturated liquid pressure at 50 ° C. of the mixed refrigerant of R410A and carbon dioxide refrigerant exceeds 4.6 MPa.

  In addition, about the physical-property value of the mixture of R410A and a carbon dioxide refrigerant | coolant, NIST Refprop ver. It is a value derived using 9.0.

  As described above, in the present embodiment, the amount of hot water supply refrigerant enclosed in the air conditioning and hot water supply system is 24.5 wt% or less of the amount of air conditioning refrigerant enclosed, so the carbon dioxide refrigerant enclosed in the first refrigeration cycle. However, even if it flows into the second refrigeration cycle through the damaged portion of the cascade heat exchanger 44, the mixing ratio of the carbon dioxide refrigerant in the mixed refrigerant of the carbon dioxide refrigerant and the air conditioning refrigerant is 24.5 wt% or less. It can be. Thereby, it becomes possible to make the operating pressure of the mixed refrigerant of the carbon dioxide refrigerant and the air conditioning refrigerant equal to or lower than the upper limit pressure of the air conditioning compressor 11 installed in the second refrigeration cycle.

  FIG. 7 is a graph showing the relationship between the mixing ratio of R32 and carbon dioxide refrigerant used as air conditioning refrigerant and the pressure.

  As shown in FIG. 7, the saturated liquid pressure at 50 ° C. of R32 is 3.1 MPa, and the upper limit pressure of the R32 compressor is set to 4.7 MPa calculated as 1.5 times higher pressure. Will be. Then, as shown in FIG. 7, the upper limit pressure of the R32 compressor is determined from the relationship between the mixing ratio of the carbon dioxide refrigerant in the mixed refrigerant of carbon dioxide refrigerant and R32 and the saturated liquid pressure at 50 ° C. The mixing ratio falling within 7 MPa can be calculated as 28.7 wt% or less.

  In the present embodiment, the amount of the hot water supply refrigerant enclosed in the air conditioning hot water supply system is 24.5 wt% or less of the amount of the air conditioning refrigerant enclosed. Thereby, even when the carbon dioxide refrigerant sealed in the first refrigeration cycle flows into the second refrigeration cycle through the damaged portion of the cascade heat exchanger 44, the carbon dioxide refrigerant and the air conditioning refrigerant The mixing ratio of the carbon dioxide refrigerant in the mixed refrigerant can be set to 28.7 wt% or less, which is equal to or lower than the use upper limit pressure of the R32 compressor.

  FIG. 8 is a graph showing the relationship between the mixing ratio of R407C used as the air conditioning refrigerant and the carbon dioxide refrigerant and the pressure.

  When R407C is used as the air-conditioning refrigerant, it is common to use the specifications of the R410A compressor, and the upper limit pressure of the R407C compressor is the same as the upper limit pressure of the R410A compressor. .6 MPa.

  As shown in FIG. 8, from the relationship between the mixing ratio of the carbon dioxide refrigerant in the mixed refrigerant of carbon dioxide refrigerant and R407C and the saturated liquid pressure at 50 ° C., the mixing ratio that falls below the upper limit use pressure of the compressor for R407C is It can be calculated as 34.9 wt% or less.

  In the present embodiment, the amount of the hot water supply refrigerant enclosed in the air conditioning hot water supply system is 24.5 wt% or less of the amount of the air conditioning refrigerant enclosed. Thereby, the mixing ratio of the carbon dioxide refrigerant in the mixed refrigerant of the carbon dioxide refrigerant and the air conditioning refrigerant can be set to 34.9 wt% or less, which is equal to or lower than the use upper limit pressure of the compressor for R407C.

  Thus, in this embodiment, since the amount of the hot water supply refrigerant enclosed in the air conditioning hot water supply system is 24.5 wt% or less of the amount of the air conditioning refrigerant enclosed, any one of R410A, R32, and R407C is used as the air conditioning refrigerant. Even when the hot water supply refrigerant is mixed, the saturated liquid pressure of the mixed refrigerant can be kept below the upper limit pressure of the air conditioning compressor 11 when the hot water supply refrigerant is mixed.

  Next, operations of the outdoor unit 10, the indoor unit 30, and the heat generation unit 40 will be described with reference to the refrigeration cycle diagram of FIG.

  During the single cooling operation, in the outdoor unit 10, the outdoor gas pipe opening / closing valve 19 is set to open and the outdoor suction pipe opening / closing valve 20 is set to closed. In the indoor unit 30, the indoor gas pipe opening / closing valve 34 is set to be closed, and the indoor intake pipe opening / closing valve 35 is set to be open. In the heat generation unit 40, the heat generation unit refrigerant flow rate adjustment valve 45 is set to be fully closed.

  The high-temperature and high-pressure air-conditioning refrigerant compressed by the air-conditioning compressor 11 enters the outdoor heat exchanger 16 via the outdoor gas pipe on-off valve 19 and is cooled by the air around the outdoor unit 10 to be in a liquid state. The liquid-state air-conditioning refrigerant flows into the liquid pipe 27 via the fully-open outdoor refrigerant flow rate adjustment valve 18 and reaches the indoor unit 30.

  The air-conditioning refrigerant that has reached the indoor unit 30 is decompressed by the indoor refrigerant flow rate adjustment valve 33 and enters a low-temperature and low-pressure gas-liquid two-phase state, and then flows into the indoor heat exchanger 31 to take heat from the indoor air. To cool. In this process, the air conditioning refrigerant evaporates, enters the suction pipe 26 via the indoor suction pipe opening / closing valve 35, and returns to the outdoor unit 10. The air-conditioning refrigerant returned to the outdoor unit 10 returns to the air-conditioning compressor 11 via the accumulator 12.

  Further, during the heating single operation, in the outdoor unit 10, the outdoor gas pipe opening / closing valve 19 is set to be closed and the outdoor suction pipe opening / closing valve 20 is set to be open. In the indoor unit 30, the indoor gas pipe opening / closing valve 34 is set to open and the indoor intake pipe opening / closing valve 35 is set to closed. In the heat generation unit 40, the heat generation unit refrigerant flow rate adjustment valve 45 is set to be fully closed.

  The high-temperature and high-pressure air-conditioning refrigerant compressed by the air-conditioning compressor 11 flows into the gas pipe 25 and reaches the indoor unit 30. The air-conditioning refrigerant that has reached the indoor unit 30 flows into the indoor heat exchanger 31 via the indoor gas pipe opening / closing valve 34, radiates heat to the indoor air, and performs heating. In this process, the air-conditioning refrigerant is condensed and liquefied, flows into the liquid pipe 27 via the fully opened indoor refrigerant flow rate adjustment valve 33, and returns to the outdoor unit 10.

  The air-conditioning refrigerant that has returned to the outdoor unit 10 is decompressed by the outdoor refrigerant flow rate adjustment valve 18 to be in a low-temperature low-pressure gas-liquid two-phase state, and then enters the outdoor heat exchanger 16 and is heated by the air around the outdoor unit 10. Evaporate. The air-conditioning refrigerant that has evaporated and vaporized returns to the air-conditioning compressor 11 via the outdoor suction pipe on-off valve 20 and the accumulator 12.

  During the hot water supply single operation, in the outdoor unit 10, the outdoor gas pipe opening / closing valve 19 is set to be closed and the outdoor suction pipe opening / closing valve 20 is set to be open. In the indoor unit 30, the indoor gas pipe opening / closing valve 34 and the indoor suction pipe opening / closing valve 35 are set. Are both closed, and in the heat generation unit 40, the heat generation unit refrigerant flow rate adjustment valve 45 is opened.

  The high-temperature and high-pressure air-conditioning refrigerant compressed by the air-conditioning compressor 11 flows into the gas pipe 25 and reaches the heat generation unit 40. On the other hand, in the heat generation unit 40, the hot water supply compressor 41 is operated, and the hot water supply refrigerant is the hot water supply compressor 41, the hot water supply heat exchanger 42, the hot water supply refrigerant flow rate adjustment valve 43, and the cascade heat exchanger 44. It circulates in the order.

  The air-conditioning refrigerant that has reached the heat generating unit 40 heats the hot water supply refrigerant in the cascade heat exchanger 44, and is cooled and liquefied, and then passes through the heat generating unit refrigerant flow rate adjustment valve 45 to the liquid pipe. 27 and returns to the outdoor unit 10.

  The air-conditioning refrigerant that has returned to the outdoor unit 10 is decompressed by the outdoor refrigerant flow rate adjustment valve 18 to be in a low-temperature low-pressure gas-liquid two-phase state, and then enters the outdoor heat exchanger 16 and is heated by the air around the outdoor unit 10. Evaporate. The air-conditioning refrigerant that has evaporated and vaporized returns to the air-conditioning compressor 11 via the outdoor suction pipe on-off valve 20 and the accumulator 12.

  On the other hand, the hot water supply refrigerant heated by the air conditioning refrigerant in the cascade heat exchanger 44 is vaporized and enters the hot water supply compressor 41. The hot water supply refrigerant compressed to a high temperature and high pressure by the hot water supply compressor 41 enters the hot water supply heat exchanger 42 and heats the heat medium to 70 to 90 ° C. In this process, the hot water supply refrigerant is cooled and liquefied, decompressed by the hot water supply refrigerant flow rate adjustment valve 43, and then returned to the cascade heat exchanger 44 again.

  If the cooling load and the heating load are substantially equal during simultaneous cooling and heating operations, both the outdoor gas pipe opening / closing valve 19 and the outdoor intake pipe opening / closing valve 20 are set to be closed in the outdoor unit 10. In the indoor unit 30 that performs cooling, the indoor gas pipe open / close valve 34 is closed and the indoor intake pipe open / close valve 35 is set to open. In the indoor unit 30 that performs heating, the indoor gas pipe open / close valve 34 is open and the indoor intake pipe open / close is opened. The valve 35 is set to be closed. In the heat generation unit 40, the heat generation unit refrigerant flow rate adjustment valve 45 is set to be fully closed.

  The high-temperature and high-pressure air-conditioning refrigerant compressed by the air-conditioning compressor 11 flows into the gas pipe 25 and reaches the indoor unit 30 that performs heating. The air-conditioning refrigerant that has reached the indoor unit 30 that performs heating flows into the indoor heat exchanger 31 via the indoor gas pipe opening / closing valve 34, radiates heat to the indoor air, and performs heating. In this process, the air-conditioning refrigerant is condensed and liquefied, and flows into the liquid pipe 27 through the fully opened indoor refrigerant flow rate adjustment valve 33.

  The liquid-state air-conditioning refrigerant that has flowed into the liquid pipe 27 reaches the indoor unit 30 that performs cooling. The air-conditioning refrigerant that has reached the indoor unit 30 that performs cooling is decompressed by the indoor refrigerant flow rate adjustment valve 33 to be in a low-temperature and low-pressure gas-liquid two-phase state, and then flows into the indoor heat exchanger 31 from the indoor air. Take away heat and cool. In this process, the air conditioning refrigerant evaporates, enters the suction pipe 26 via the indoor suction pipe opening / closing valve 35, and returns to the outdoor unit 10. The air-conditioning refrigerant returned to the outdoor unit 10 returns to the air-conditioning compressor 11 via the accumulator 12.

  When the cooling load is larger than the heating load, since there is not enough liquid refrigerant to be supplied from the indoor unit 30 that performs heating to the indoor unit 30 that performs cooling, a part of the outdoor unit 10 is used as the outdoor heat exchanger. 16 is generated. That is, the outdoor gas pipe on / off valve 19 is opened while the outdoor suction pipe on / off valve 20 is closed, and a part of the refrigerant discharged from the air conditioning compressor 11 is supplied to the outdoor heat exchanger 16 to be liquefied. Then, the refrigerant is supplied to the indoor unit 30 that performs cooling via the outdoor refrigerant flow rate adjustment valve 18 and the liquid pipe 27.

  Conversely, when the heating load is larger than the cooling load, the liquid refrigerant supplied from the indoor unit 30 that performs heating cannot be completely evaporated in the indoor unit 30 that performs cooling. Evaporation is performed by the outdoor heat exchanger 16 of the outdoor unit 10. That is, the outdoor suction pipe on / off valve 20 is opened while the outdoor gas pipe on / off valve 19 is closed, and the liquid refrigerant flowing out from the indoor unit 30 that performs heating is returned to the outdoor unit 10 via the liquid pipe 27.

  The liquid refrigerant returned to the outdoor unit 10 is depressurized by the outdoor refrigerant flow rate adjusting valve 18 and then evaporated by the outdoor heat exchanger 16. The vaporized air-conditioning refrigerant returns to the accumulator 12 and the air-conditioning compressor 11 via the outdoor suction pipe opening / closing valve 20.

  If the cooling load and the hot water supply load are substantially equal during the simultaneous operation of cooling and hot water supply, both the outdoor gas pipe opening / closing valve 19 and the outdoor suction pipe opening / closing valve 20 are set to be closed in the outdoor unit 10. In the indoor unit 30 that performs cooling, the indoor gas pipe opening / closing valve 34 is closed, the indoor intake pipe opening / closing valve 35 is set to open, and the heat generation unit refrigerant flow rate adjustment valve 45 is opened in the heat generation unit 40.

  The high-temperature and high-pressure air-conditioning refrigerant compressed by the air-conditioning compressor 11 flows into the gas pipe 25 and reaches the heat generation unit 40. On the other hand, in the heat generation unit 40, the hot water supply compressor 41 is operated, and the hot water supply refrigerant is the hot water supply compressor 41, the hot water supply heat exchanger 42, the hot water supply refrigerant flow rate adjustment valve 43, and the cascade heat exchanger 44. It circulates in the order.

  The air-conditioning refrigerant that has reached the heat generating unit 40 heats the hot water supply refrigerant in the cascade heat exchanger 44, and is cooled and liquefied, and then passes through the heat generating unit refrigerant flow rate adjustment valve 45 to the liquid pipe. 27 flows in.

  The liquid-state air-conditioning refrigerant that has flowed into the liquid pipe 27 reaches the indoor unit 30 that performs cooling. The air-conditioning refrigerant that has reached the indoor unit 30 that performs cooling is decompressed by the indoor refrigerant flow rate adjustment valve 33 to be in a low-temperature and low-pressure gas-liquid two-phase state, and then flows into the indoor heat exchanger 31 from the indoor air. Take away heat and cool. In this process, the air conditioning refrigerant evaporates, enters the suction pipe 26 via the indoor suction pipe opening / closing valve 35, and returns to the outdoor unit 10. The air-conditioning refrigerant returned to the outdoor unit 10 returns to the air-conditioning compressor 11 via the accumulator 12.

  On the other hand, the hot water supply refrigerant heated by the air conditioning refrigerant in the cascade heat exchanger 44 is vaporized and enters the hot water supply compressor 41. The hot water supply refrigerant compressed to a high temperature and high pressure by the hot water supply compressor 41 enters the hot water supply heat exchanger 42 and heats the heat medium to 70 to 90 ° C. In this process, the hot water supply refrigerant is cooled and liquefied, decompressed by the hot water supply refrigerant flow rate adjustment valve 43, and then returned to the cascade heat exchanger 44 again.

  When the cooling load is larger than the hot water supply load, since there is not enough liquid refrigerant to be supplied from the heat generation unit 40 to the indoor unit 30 that performs cooling, a part of the refrigerant is generated by the outdoor heat exchanger 16 of the outdoor unit 10. . That is, the outdoor gas pipe on / off valve 19 is opened while the outdoor suction pipe on / off valve 20 is closed, and a part of the refrigerant discharged from the air conditioning compressor 11 is supplied to the outdoor heat exchanger 16 to be liquefied. Then, the refrigerant is supplied to the indoor unit 30 that performs cooling via the outdoor refrigerant flow rate adjustment valve 18 and the liquid pipe 27.

  On the other hand, when the hot water supply load is larger than the cooling load, the liquid refrigerant supplied from the heat generation unit 40 cannot be completely evaporated in the indoor unit 30 that performs cooling. In the outdoor heat exchanger 16. That is, the outdoor suction pipe on / off valve 20 is opened while the outdoor gas pipe on / off valve 19 is closed, and a part of the liquid refrigerant flowing out from the indoor unit 30 for heating is passed through the liquid pipe 27 to the outdoor unit 10. Return to.

  The liquid refrigerant returned to the outdoor unit 10 is depressurized by the outdoor refrigerant flow rate adjusting valve 18 and then evaporated by the outdoor heat exchanger 16. The vaporized air-conditioning refrigerant returns to the accumulator 12 and the air-conditioning compressor 11 via the outdoor suction pipe opening / closing valve 20.

  During the simultaneous operation of heating and hot water supply, in the outdoor unit 10, the outdoor gas pipe opening / closing valve 19 is set to be closed and the outdoor suction pipe opening / closing valve 20 is set to be open. In the indoor unit 30, the indoor gas pipe opening / closing valve 34 is set to open and the indoor intake pipe opening / closing valve 35 is set to closed. In the heat generation unit 40, the heat generation unit refrigerant flow rate adjustment valve 45 is opened.

  The high-temperature and high-pressure air-conditioning refrigerant compressed by the air-conditioning compressor 11 flows into the gas pipe 25 and reaches the indoor unit 30 and the heat generation unit 40. The air-conditioning refrigerant that has reached the indoor unit 30 flows into the indoor heat exchanger 31 via the indoor gas pipe opening / closing valve 34, radiates heat to the indoor air, and performs heating. In this process, the air-conditioning refrigerant is condensed and liquefied, and flows into the liquid pipe 27 through the fully opened indoor refrigerant flow rate adjustment valve 33.

  The air-conditioning refrigerant that has reached the heat generating unit 40 heats the hot water supply refrigerant in the cascade heat exchanger 44, and is cooled and liquefied, and then passes through the heat generating unit refrigerant flow rate adjustment valve 45 to the liquid pipe. 27 flows in. This liquid refrigerant merges with the liquid refrigerant that has flowed out of the indoor unit 30 that performs heating, and returns to the outdoor unit 10. The liquid refrigerant returned to the outdoor unit is depressurized by the outdoor refrigerant flow control valve 18 and then evaporated by the outdoor heat exchanger 16. The vaporized air-conditioning refrigerant returns to the accumulator 12 and the air-conditioning compressor 11 via the outdoor suction pipe opening / closing valve 20.

  On the other hand, the hot water supply refrigerant heated by the air conditioning refrigerant in the cascade heat exchanger 44 is vaporized and enters the hot water supply compressor 41. The hot water supply refrigerant compressed to a high temperature and high pressure by the hot water supply compressor 41 enters the hot water supply heat exchanger 42 and heats the heat medium to 70 to 90 ° C. In this process, the hot water supply refrigerant is cooled and liquefied, decompressed by the hot water supply refrigerant flow rate adjustment valve 43, and then returned to the cascade heat exchanger 44 again.

  During the simultaneous operation of cooling, heating and hot water supply, if the sum of the cooling load and the heating load and hot water supply load is substantially equal, both the outdoor gas pipe opening / closing valve 19 and the outdoor intake pipe opening / closing valve 20 are closed in the outdoor unit 10. Set to In the indoor unit 30 that performs cooling, the indoor gas pipe open / close valve 34 is closed and the indoor intake pipe open / close valve 35 is set to open. In the indoor unit 30 that performs heating, the indoor gas pipe open / close valve 34 is open and the indoor intake pipe open / close is opened. The valve 35 is set to be closed. In the heat generation unit 40, the heat generation unit refrigerant flow rate adjustment valve 45 is opened.

  The high-temperature and high-pressure air-conditioning refrigerant compressed by the air-conditioning compressor 11 flows into the gas pipe 25 and reaches the indoor unit 30 and the heat generation unit 40 that perform heating. On the other hand, in the heat generation unit 40, the hot water supply compressor 41 is operated, and the hot water supply refrigerant is the hot water supply compressor 41, the hot water supply heat exchanger 42, the hot water supply refrigerant flow rate adjustment valve 43, and the cascade heat exchanger 44. It circulates in the order.

  The air-conditioning refrigerant that has reached the indoor unit 30 that performs heating flows into the indoor heat exchanger 31 via the indoor gas pipe opening / closing valve 34, radiates heat to the indoor air, and performs heating. In this process, the air-conditioning refrigerant is condensed and liquefied, and flows into the liquid pipe 27 through the fully opened indoor refrigerant flow rate adjustment valve 33.

  The air-conditioning refrigerant that has reached the heat generating unit 40 heats the hot water supply refrigerant in the cascade heat exchanger 44, and is cooled and liquefied, and then passes through the heat generating unit refrigerant flow rate adjustment valve 45 to the liquid pipe. 27 flows in.

  The indoor unit 30 that performs heating and the liquefied air-conditioning refrigerant that has flowed into the liquid pipe 27 from the heat generation unit 40 merge to reach the indoor unit 30 that performs cooling. The air-conditioning refrigerant that has reached the indoor unit 30 that performs cooling is decompressed by the indoor refrigerant flow rate adjustment valve 33 to be in a low-temperature and low-pressure gas-liquid two-phase state, and then flows into the indoor heat exchanger 31 from the indoor air. Take away heat and cool. In this process, the air conditioning refrigerant evaporates, enters the suction pipe 26 via the indoor suction pipe opening / closing valve 35, and returns to the outdoor unit 10. The air-conditioning refrigerant returned to the outdoor unit 10 returns to the air-conditioning compressor 11 via the accumulator 12.

  On the other hand, the hot water supply refrigerant heated by the air conditioning refrigerant in the cascade heat exchanger 44 is vaporized and enters the hot water supply compressor 41. The hot water supply refrigerant compressed to a high temperature and high pressure by the hot water supply compressor 41 enters the hot water supply heat exchanger 42 and heats the heat medium to 70 to 90 ° C. In this process, the hot water supply refrigerant is cooled and liquefied, decompressed by the hot water supply refrigerant flow rate adjustment valve 43, and then returned to the cascade heat exchanger 44 again.

  Note that when the cooling load is larger than the sum of the heating load and the hot water supply load, there is not enough liquid refrigerant to be supplied from the indoor unit 30 that performs heating and the indoor unit 30 that performs cooling from the heat generation unit 40. Is generated by the outdoor heat exchanger 16 of the outdoor unit 10. That is, the outdoor gas pipe on / off valve 19 is opened while the outdoor suction pipe on / off valve 20 is closed, and a part of the refrigerant discharged from the air conditioning compressor 11 is supplied to the outdoor heat exchanger 16 to be liquefied. Then, the refrigerant is supplied to the indoor unit 30 that performs cooling via the outdoor refrigerant flow rate adjustment valve 18 and the liquid pipe 27.

  On the other hand, when the sum of the heating load and the hot water supply load is larger than the cooling load, the liquid refrigerant supplied from the indoor unit 30 that performs heating and the heat generation unit 40 cannot be completely evaporated in the indoor unit 30 that performs cooling. A part of the liquid refrigerant is evaporated by the outdoor heat exchanger 16 of the outdoor unit 10. That is, the outdoor intake pipe on / off valve 20 is opened while the outdoor gas pipe on / off valve 19 is closed, and a part of the liquid refrigerant flowing out from the indoor unit 30 for heating and the heat generating unit 40 is passed through the liquid pipe 27. To return to the outdoor unit 10.

  The liquid refrigerant returned to the outdoor unit 10 is depressurized by the outdoor refrigerant flow rate adjusting valve 18 and then evaporated by the outdoor heat exchanger 16. The vaporized air-conditioning refrigerant returns to the accumulator 12 and the air-conditioning compressor 11 via the outdoor suction pipe opening / closing valve 20.

  Next, the operation of the heat medium in the heat generation unit 40 will be described with reference to FIGS.

  The hot water supply compressor 41 and the heat medium pump 46 are operated during a single hot water supply operation, a simultaneous operation of cooling and hot water supply, a simultaneous operation of heating and hot water supply, and a simultaneous operation of cooling, heating and hot water supply. While the heat medium pump is in operation, the heat medium flows into the heat generation unit 40 from the outside of the heat generation unit 40 such as waterworks and enters the heat medium pump 46 through the heat medium pipe 63.

  The heat medium flowing into the heat medium pump 46 flows into the heat medium pipe 64 from the discharge port and enters the hot water supply heat exchanger 42. The heat medium exchanges heat with the hot water supply refrigerant discharged from the hot water supply compressor 41 in the hot water supply heat exchanger 42, which is a double-pipe heat exchanger, and is heated to 70 to 90 ° C. It is sent out of the heat generation unit 40 via the heat medium pipe 65.

  As described above, in the path through which the heat medium flows (the heat medium pipe 63 → the heat medium pump 46 → the heat medium pipe 64 → the hot water supply heat exchanger 42 → the heat medium pipe 65), the resin material and copper are mixed and are different. There is a connection between the materials.

  In the present embodiment, the hot water supply heat exchanger 42 is not in contact with the bottom plate member 51 to which the hot water supply compressor 41 is fixed, but is fixed to the side plate member 52 and installed. For this reason, vibrations during operation of the hot water supply compressor 41 are not directly transmitted to the hot water supply heat exchanger 42 through the bottom plate member 51.

  Here, during the operation of the air conditioning and hot water supply system, a wall separating the flow path of the hot water supply refrigerant and the air conditioning refrigerant in the cascade heat exchanger 44 is damaged, and the hot water supply refrigerant is mixed into the first refrigeration cycle from the damaged portion. In such a case, the air conditioning and hot water supply system will not stop instantaneously. For this reason, it falls into the condition where an air-conditioning hot-water supply system is drive | operated in the state where the pressure rose.

  In this case, in the present embodiment, the amount of carbon dioxide refrigerant sealed in the first refrigeration cycle is 24.5 wt% or less with respect to the amount of air-conditioning refrigerant sealed in the second refrigeration cycle. Thereby, even when the carbon dioxide refrigerant sealed in the first refrigeration cycle flows into the second refrigeration cycle, the mixing ratio of the carbon dioxide refrigerant in the mixture of the carbon dioxide refrigerant and the air conditioning refrigerant is 24.5 wt%. The following can be held: Therefore, the operating pressure of the second refrigeration cycle can be made equal to or lower than the upper limit pressure for use of the air conditioning compressor 11 installed in the second refrigeration cycle.

  As described above, in the present embodiment, the amount of carbon dioxide refrigerant sealed in the first refrigeration cycle is 24.5 wt% or less with respect to the amount of air-conditioning refrigerant sealed in the second refrigeration cycle. . As a result, even when the carbon dioxide refrigerant sealed in the first refrigeration cycle flows into the second refrigeration cycle through the damaged portion of the cascade heat exchanger 44, the carbon dioxide refrigerant in the mixture of the carbon dioxide refrigerant and the air conditioning refrigerant. The mixing ratio of the carbon refrigerant can be maintained at 24.5 wt% or less. Therefore, the operating pressure of the second refrigeration cycle can be made equal to or lower than the upper limit pressure for use of the air conditioning compressor 11 installed in the second refrigeration cycle. As a result, the durability of the air conditioning compressor 11 is not impaired, and the reliability of the second refrigeration cycle can be improved.

  The cascade heat exchanger 44 may be a type of heat exchanger having a large heat transfer area with respect to the volume, such as a plate heat exchanger or a shell-and-tube heat exchanger. Thereby, the amount of carbon dioxide refrigerant sealed in the first refrigeration cycle can be reduced. As a result, the amount of carbon dioxide refrigerant flowing into the second refrigeration cycle through the damaged portion in the cascade heat exchanger 44 can be reduced. As a result, it is possible to suppress an increase in the operating pressure of the mixed refrigerant of the hot water supply refrigerant and the air conditioning refrigerant, and to prevent the durability of the air conditioning compressor 11 from being impaired.

  Moreover, you may use the type of heat exchanger with a large heat-transfer area with respect to the volume, such as a plate type heat exchanger and a shell and tube type heat exchanger, for the hot water supply heat exchanger. Thereby, the amount of carbon dioxide refrigerant sealed in the first refrigeration cycle can be reduced. As a result, the amount of carbon dioxide refrigerant flowing into the second refrigeration cycle through the damaged portion in the cascade heat exchanger 44 can be reduced. As a result, it is possible to suppress an increase in the operating pressure of the mixed refrigerant of the hot water supply refrigerant and the air conditioning refrigerant, and to prevent the durability of the air conditioning compressor 11 from being impaired.

  In addition, in the said embodiment, although the case where any one of R410A, R32, R407C was used as a refrigerant | coolant for an air conditioning was demonstrated, it is not limited to this. That is, even when other air conditioning refrigerants are used, the amount of hot water supply refrigerant sealed in the first refrigeration cycle is equal to the saturated liquid pressure of the mixed refrigerant when the hot water supply refrigerant is mixed with the air conditioning refrigerant. If the amount is equal to or lower than the upper limit pressure of the compressor 11 for use, the same action and effect can be obtained.

  The present invention provides a highly reliable second refrigeration cycle in an air conditioning and hot water supply system capable of simultaneously supplying hot and cold heat necessary for cooling, heating, and hot water supply without impairing the durability of the air conditioning compressor 11. It can be suitably used.

DESCRIPTION OF SYMBOLS 10 Outdoor unit 11 Air conditioner compressor 16 Outdoor heat exchanger 30 Indoor unit 31 Indoor heat exchanger 40 Heat generating unit 41 Hot water supply compressor 42 Hot water supply heat exchanger 43 Hot water supply refrigerant flow rate adjustment valve 44 Cascade heat exchanger 45 Heat Generation unit refrigerant flow rate adjusting valve 46 Heat medium pump 50 Casing 51 Bottom plate member 52, 53 Side plate member 61 Vibration isolator 63, 64, 65 Heat medium pipe 70 Heat transfer plate 71 Refrigerant flow path space 73 Nozzle 75 Pipe

Claims (5)

A hot water supply compressor that compresses the hot water supply refrigerant, a hot water supply heat exchanger that exchanges heat between the hot water supply refrigerant and the hot water supply heat medium, and a cascade heat exchanger that exchanges heat between the hot water supply refrigerant and the air conditioning refrigerant A first refrigeration cycle comprising:
An air conditioning compressor that compresses the air conditioning refrigerant, an outdoor heat exchanger that exchanges heat between the air conditioning refrigerant and outdoor air, an indoor heat exchanger that exchanges heat between the air conditioning refrigerant and indoor air, and A second refrigeration cycle comprising a cascade heat exchanger;
In the air conditioning and hot water supply system equipped with
The amount of the hot water supply refrigerant enclosed in the first refrigeration cycle is such that the saturated liquid pressure of the mixed refrigerant when the hot water supply refrigerant is mixed with the air conditioning refrigerant is equal to or lower than the upper limit pressure of the air conditioning compressor. The amount of air conditioning hot water supply system that is The hot water supply refrigerant is a carbon dioxide refrigerant, and the air conditioning refrigerant is any one of R410A, R32, and R407C.
2. The air conditioning hot water supply according to claim 1, wherein an amount of the hot water supply refrigerant sealed in the first refrigeration cycle is 24.5 wt% or less of an amount of the air conditioning refrigerant sealed in the second refrigeration cycle. system.   The air conditioning and hot water supply system according to claim 1 or 2, wherein the cascade heat exchanger is either a plate heat exchanger or a shell and tube heat exchanger.   The air-conditioning hot-water supply system according to claim 1 or 2, wherein the hot-water supply heat exchanger is either a plate heat exchanger or a shell-and-tube heat exchanger.   The air-conditioning hot water supply system according to claim 3, wherein the hot water supply heat exchanger is either a plate heat exchanger or a shell and tube heat exchanger.

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