JP5205079B2 - Heat pump water heater / heater - Google Patents

Description

  The present invention relates to a heat pump hot water supply and heating device that stores hot water in a hot water storage tank by circulating water in the hot water storage tank to a radiator of a heat pump refrigerant circuit.

  Conventionally, this type of heat pump type hot water supply apparatus has a heat pump refrigerant circuit by connecting a hot water storage tank unit having a hot water storage tank capable of storing hot water, a decompression device such as a compressor, a radiator, and an expansion valve, and an evaporator. It consists of a configured heat pump unit. The radiator is configured such that heat from the hot water storage tank of the hot water storage tank unit and the refrigerant flowing through the refrigerant circuit of the heat pump unit can be exchanged. And the water of a hot water storage tank is circulated to a radiator, and heat is exchanged with the high-temperature / high-pressure refrigerant from the compressor flowing through the radiator. As a result, water that has been deprived of heat from the refrigerant and heated to become hot hot water is returned to the hot water storage tank and stored in the hot water storage tank.

  Further, the refrigerant that has dissipated heat by removing heat from the water by the radiator is decompressed by the expansion valve (main throttle means) and then flows into the evaporator. The refrigerant that has flowed into the evaporator absorbs heat from the surrounding air and evaporates in the evaporator, and is then sucked into the compressor and compressed again.

  In such a refrigerant cycle, the expansion valve is controlled by the discharge refrigerant temperature discharged from the compressor. That is, when the valve opening of the main throttle means is reduced, the refrigerant temperature discharged from the compressor increases, and when the valve opening is increased, the discharge refrigerant temperature decreases, so the discharge refrigerant temperature discharged from the compressor is predetermined. A target value that becomes the value of is set, and the valve opening of the main throttle means is controlled so as to approach the target value.

  In recent years, in this type of heat pump type hot water supply apparatus, it has become impossible to use a chlorofluorocarbon refrigerant due to natural environmental problems and the like. For this reason, an attempt has been made to use carbon dioxide, which is a natural refrigerant, as an alternative to a fluorocarbon refrigerant. It is known that the carbon dioxide refrigerant is a refrigerant having a high and low pressure difference, has a low critical pressure, and a high pressure side of the refrigerant cycle is brought into a supercritical state by compression.

  In such a supercritical refrigerant cycle, the heat source temperature on the radiator side (the temperature of the outside air that is a heat medium that exchanges heat with the radiator, the temperature of the room, the water supply temperature of the hot water supply device, etc. can be mentioned. Is equivalent to the temperature of water from the hot water storage tank, that is, the temperature of water entering from the hot water storage tank entering the radiator). Since the specific enthalpy at the entrance is increased, there has been a problem that the refrigeration effect is significantly reduced. In this case, in order to secure the refrigerating capacity, it is necessary to increase the high pressure, so that the compression power increases and the coefficient of performance decreases.

  For this reason, the refrigerant cooled by the radiator is divided into two refrigerant streams, one of the divided refrigerant streams (first refrigerant stream) is throttled by the auxiliary throttle means, and one of the passages of the intermediate heat exchanger (first passage) And the other refrigerant flow (second refrigerant flow) is exchanged heat with the first flow path of the intermediate heat exchanger. A two-stage compression / single-stage expansion / intercooling cycle that flows through the other passage (second flow path) provided, evaporates in the evaporator via the main throttle means, and then sucks into the low-pressure part of the compressor, so-called It has been proposed to use a split cycle (split cycle (registered trademark)).

This split cycle allows the refrigerant that has been radiated by the radiator to be diverted, and the second refrigerant flow can be cooled by the first refrigerant flow decompressed and expanded by the auxiliary throttle means. The specific enthalpy at the vessel inlet can be reduced. As a result, the refrigeration effect can be increased, and the performance can be effectively improved as compared to conventional devices (see, for example, Patent Document 1).
JP 2006-242557 A

  By the way, in the split cycle described above, the effect of cooling the second refrigerant flow by the first refrigerant flow in the intermediate heat exchanger is the flow rate of the first refrigerant flow and the second refrigerant flow flowing through the intermediate heat exchanger. Will be dependent. That is, if the valve opening of the auxiliary throttle means for reducing the pressure of the first refrigerant flow is too small, the first refrigerant flow flowing to the intermediate heat exchanger is too small. Can not be cooled effectively. Therefore, the effect of improving the efficiency of the cycle by reducing the specific enthalpy at the evaporator inlet cannot be obtained. Further, in this case, since the second refrigerant flow cannot be effectively cooled by the first refrigerant flow in the intermediate heat exchanger, the refrigerant temperature sucked into the compressor becomes high, and as a result, the refrigerant discharged from the compressor The temperature will rise.

  On the other hand, when the valve opening degree of the auxiliary throttle means is too large, the first refrigerant flow becomes excessive. As a result, the first refrigerant flow sucked into the intermediate pressure portion of the compressor causes an abnormal increase in the pressure of the refrigerant discharged from the compressor or an abnormal decrease in the temperature of the refrigerant discharged from the compressor. Will occur. Furthermore, if the first refrigerant flow becomes excessive, it cannot be completely gasified by heat exchange with the second refrigerant flow in the intermediate heat exchanger, and the intermediate pressure portion of the compressor is wet (gas and There is a risk that the compressor may be damaged by sucking refrigerant in a two-phase state in which liquids are mixed or in a liquid state.

  Therefore, in the split cycle, it is necessary to control the valve opening degree of the auxiliary throttle means in addition to the control of the main throttle means described above. In particular, in such a split cycle, when the valve opening of the auxiliary throttle means is large and the first refrigerant flow is large, the relationship between the main throttle means and the discharge temperature may be reversed. That is, when the valve opening of the main throttle means is reduced in the normal cycle, the refrigerant discharge refrigerant temperature rises. In the split cycle, when the valve opening of the main throttle means is reduced, the compressor discharge refrigerant temperature is reduced. There is a case where the relationship decreases.

  Thus, when the relationship between the valve opening of the main throttle means and the discharged refrigerant temperature is reversed, problems such as a high pressure increase abnormally or a refrigerant temperature discharged from the compressor abnormally tend to occur. That is, in the conventional control, when the discharge temperature is lower than a predetermined value, the valve opening degree of the main throttle means is reduced, so that the discharge refrigerant temperature is further lowered and the high pressure is further increased. This increases the difference between the discharge temperature and the target value of the discharge temperature. That is, since the discharge temperature is lowered in a direction lower than the target value, the difference between the discharge temperature and the target temperature is widened. In this case, since the valve opening degree of the main throttle means is controlled to be further reduced, the temperature of the discharged refrigerant is further lowered, and there is a problem in that the high pressure is abnormally increased.

  The present invention has been made in order to solve the problems of the related art, and an object of the present invention is to realize a stable and highly efficient operation in a heat pump hot water supply and heating device.

A heat pump hot water supply and heating device of the present invention includes a heat pump refrigerant circuit configured to include a compressor, a refrigerant-to-water heat exchanger, and an evaporator, and a hot water storage tank capable of storing hot water. The water is stored in a hot water storage tank by circulating the water in the refrigerant-to-water heat exchanger, and the heat pump refrigerant circuit includes a compressor, a refrigerant-to-water heat exchanger, auxiliary throttle means, An intermediate heat exchanger, a main throttle means, and an evaporator, the refrigerant coming out of the refrigerant-to-water heat exchanger is divided into two flows, and the first refrigerant flow is passed through the auxiliary throttle means to the intermediate heat exchanger And then the second refrigerant flow through the second flow path of the intermediate heat exchanger and then through the main throttle means to the evaporator, so that the first heat is passed through the intermediate heat exchanger. Heat exchange between the refrigerant flow and the second refrigerant flow, and the refrigerant discharged from the evaporator is used as a low-pressure part of the compressor. A discharge refrigerant temperature detecting means for sucking the first refrigerant flow from the intermediate heat exchanger into the intermediate pressure portion of the compressor and detecting the temperature of the refrigerant discharged from the compressor; and the intermediate heat exchanger The intermediate heat exchanger inlet refrigerant temperature detection means and the intermediate heat exchanger outlet refrigerant temperature detection means for detecting the temperature of the first refrigerant flow at the inlet and the outlet of the refrigerant, and the main throttle means and the auxiliary based on the outputs of these temperature detection means And a control device for controlling the valve opening of the throttle means, and this control device is arranged so that the temperature of the refrigerant discharged from the compressor rises when the valve opening of the main throttle means is reduced. The valve opening degree of the means is controlled .

According to a second aspect of the present invention, there is provided the heat pump hot water supply / room heating device according to the first aspect, wherein the control device is configured such that the temperature of the refrigerant discharged from the compressor is a predetermined discharge temperature target based on the output of the discharge refrigerant temperature detecting means. The valve opening degree of the main throttle means is controlled so as to become a value, and based on the outputs of the intermediate heat exchanger inlet refrigerant temperature detecting means and the intermediate heat exchanger outlet refrigerant temperature detecting means, The valve opening degree of the auxiliary throttle means is controlled so that the temperature difference of the refrigerant flow of one reaches a predetermined temperature difference target value.

According to a third aspect of the present invention, there is provided the heat pump type hot water supply / room heating device according to the second aspect , wherein the control device is configured such that when the temperature of the refrigerant discharged from the compressor is lower than the discharge temperature target value, the valve opening degree of the main throttle means When the temperature difference between the first refrigerant flow at the outlet and the inlet of the intermediate heat exchanger is smaller than the target temperature difference, the valve opening of the auxiliary throttle means is reduced. It is characterized by expanding.

According to a fourth aspect of the present invention, there is provided the heat pump hot water supply / room heating device according to the second or third aspect , wherein the control device is configured such that the refrigerant of the first refrigerant flow at the inlet of the intermediate heat exchanger is in a two-phase region. The temperature difference target value is set to a first temperature difference target value at which the refrigerant in the first refrigerant flow at the outlet of the intermediate heat exchanger is in a gas state, and the refrigerant in the first refrigerant flow at the inlet of the intermediate heat exchanger exceeds When it is in the critical region, the temperature difference target value is set to a second temperature difference target value that is larger than the first temperature difference target value.

The heat pump hot water supply / room heating device according to the invention of claim 5 is an incoming air temperature detecting means for detecting an incoming water temperature entering the refrigerant-to-water heat exchanger in the invention of claim 2 or claim 3 , and an outside air detecting the outside air temperature. Temperature control means, and the control device expands the temperature difference target value when the incoming water temperature is high or when the outside air temperature is high, based on the outputs of these temperature detection means.

The heat pump hot water supply / room heating device of the invention of claim 6 is the control device according to claim 5 , wherein the control device has a first function when the incoming water temperature is lower than a predetermined value or when the outside air temperature is higher than a predetermined value. It is characterized by not flowing a refrigerant flow.

According to the present invention, a heat pump refrigerant circuit configured to include a compressor, a refrigerant-to-water heat exchanger, and an evaporator, and a hot water storage tank capable of storing hot water, the water in the hot water storage tank is refrigerated. In a heat pump hot water supply and heating device that stores hot water in a hot water storage tank by circulating it to a water heat exchanger, the heat pump refrigerant circuit includes a compressor, a refrigerant to water heat exchanger, auxiliary throttle means, and intermediate heat. An exchanger, a main throttle means and an evaporator, the refrigerant exiting from the refrigerant-to-water heat exchanger is divided into two flows, and the first refrigerant flow is passed through the auxiliary throttle means to the second of the intermediate heat exchanger The first refrigerant flows through the first flow path, the second refrigerant flow flows through the second flow path of the intermediate heat exchanger, and then flows through the main throttle means to the evaporator, thereby causing the first refrigerant to flow through the intermediate heat exchanger. Heat exchange between the second stream and the second refrigerant stream, and the refrigerant exiting the evaporator A discharge refrigerant temperature detecting means for sucking the first refrigerant flow from the intermediate heat exchanger into the intermediate pressure portion of the compressor and detecting the temperature of the refrigerant discharged from the compressor; and the intermediate heat exchanger The intermediate heat exchanger inlet refrigerant temperature detection means and the intermediate heat exchanger outlet refrigerant temperature detection means for detecting the temperature of the first refrigerant flow at the inlet and the outlet of the refrigerant, and the main throttle means and the auxiliary based on the outputs of these temperature detection means And a control device for controlling the valve opening degree of the throttle means, and the auxiliary throttle means so that the temperature of the refrigerant discharged from the compressor rises when the control device reduces the valve opening degree of the main throttle means. Since the valve opening degree of the main throttle means is controlled, the disadvantage that the relationship between the main throttle means and the discharge temperature is reversed such that the refrigerant discharge refrigerant temperature decreases when the valve opening degree of the main throttle means is reduced is avoided. Can do.

In particular, according to the second aspect of the invention, the control device sets the valve opening degree of the main throttle means based on the output of the discharged refrigerant temperature detecting means so that the temperature of the refrigerant discharged from the compressor becomes a predetermined discharge temperature target value. And the temperature difference between the first refrigerant flow at the outlet and the inlet of the intermediate heat exchanger is a predetermined temperature difference based on the outputs of the intermediate heat exchanger inlet refrigerant temperature detecting means and the intermediate heat exchanger outlet refrigerant temperature detecting means. Since the valve opening degree of the auxiliary throttle means is controlled so as to reach the target value, for example, as in the invention of claim 3 , the control device controls the main throttle when the temperature of the refrigerant discharged from the compressor is lower than the discharge temperature target value. The valve opening of the auxiliary throttle means is reduced when the temperature difference between the first refrigerant flow at the outlet and the inlet of the intermediate heat exchanger is smaller than the temperature difference target value. And enlarge when it ’s bigger , It is possible to control the flow rate of the first refrigerant stream and a second refrigerant flow through the intermediate heat exchanger to the optimum amount.

According to a fourth aspect of the present invention, in the second or third aspect of the present invention, when the refrigerant of the first refrigerant flow at the inlet of the intermediate heat exchanger is in the two-phase region, the control device is a temperature difference target. The value is a first temperature difference target value at which the refrigerant of the first refrigerant flow at the outlet of the intermediate heat exchanger is in a gas state, and the refrigerant of the first refrigerant flow at the inlet of the intermediate heat exchanger is in the supercritical region In this case, since the temperature difference target value is set to the second temperature difference target value that is larger than the first temperature difference target value, the first refrigerant flow and the first refrigerant flow in the intermediate heat exchanger according to the state of the first refrigerant flow. The amount of heat exchange with the second refrigerant flow can be optimized.

According to a fifth aspect of the present invention, the controller includes an incoming water temperature detecting means for detecting an incoming water temperature entering the refrigerant-to-water heat exchanger, and an outside air temperature detecting means for detecting an outside air temperature. Based on the output of the means, when the incoming water temperature is high or the outside air temperature is high, the temperature difference target value is expanded, so that the heat exchange capability in the intermediate heat exchanger is improved and the second refrigerant entering the evaporator The flow can be effectively cooled and the specific enthalpy can be reduced.

In particular, the control device as in the invention of claim 6 has a small performance improvement effect due to the split cycle, and stable operation is difficult, for example, when the incoming water temperature is lower than a predetermined value as in claim 6 , or When the outside air temperature is higher than the predetermined value, the first refrigerant flow is not flowed, so that the operation by the normal cycle can be performed.

  In general, the present invention makes it possible to realize a stable and highly efficient operation of the heat pump hot water supply / room heating device.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 shows an overall configuration diagram of an embodiment of a heat pump type hot water supply and heating apparatus to which the present invention is applied. The heat pump hot water supply / room heating apparatus H includes a heat pump unit 10 and a hot water storage tank unit 30.

  The heat pump unit 10 includes a compressor 11, a radiator 12, a flow divider 13, a second expansion valve 14 as auxiliary throttle means, an intermediate heat exchanger 15, an expansion valve 17 as main throttle means, and an evaporator 18. Thus, a heat pump refrigerant circuit is configured by connecting these pipes.

  The compressor 11 according to the present embodiment includes an electric element (a hermetic container and electric element are not shown) in a hermetic container (case of the compressor 11), and a low-stage compression unit driven by the electric element. The first compression element 11A and the second compression element 11B as high-stage compression means are provided, and after the refrigerant compressed by the first compression element 11A is discharged into the sealed container 16, the second This is an internal intermediate pressure type compressor that sucks into the compression element 11B and compresses it. In this case, the low pressure portion of the compressor 11 corresponds to the suction side of the first compression element 11A, and the intermediate pressure portion corresponds to the suction side of the second compression element 11B from the discharge side of the first compression element 11A. To do. That is, the inside 16 of the sealed container also corresponds to the intermediate pressure part. That is, the compressor 11 of the present embodiment sucks and compresses a low-pressure refrigerant into the first compression element 11A to obtain an intermediate pressure, discharges the compressed air into the sealed container 16, and then performs the second compression from the sealed container 16 to the second compression. It is configured to be sucked into the element 11B and compressed to a high pressure.

  One end of a refrigerant discharge pipe 42 is connected to the refrigerant discharge side of the second compression element 11B, and high-temperature and high-pressure refrigerant gas compressed by the second compression element 11B is compressed from the refrigerant discharge pipe 42. It is discharged outside the machine 11. The other end of the refrigerant discharge pipe 42 is connected to one end of the radiator 12 (the refrigerant inlet side of the heating unit 12A) which will be described later. A pipe 44 that leads to the flow divider 13 is connected to the other end of the radiator 12 (that is, the refrigerant outlet side of the heating unit 12A).

  The flow divider 13 is a flow dividing means for branching the refrigerant that has exited the heating unit 12A of the radiator 12 into two flows. The flow divider 13 of this embodiment divides the refrigerant from the radiator 12 into two flows, a first refrigerant flow and a second refrigerant flow, and the first refrigerant flow passes through the expansion valve 14 to perform intermediate heat exchange. The second refrigerant flow is made to flow to the second flow path 15B of the intermediate heat exchanger 15 through the second refrigerant flow path reaching the first flow path 15A of the evaporator 15, and then the evaporator 18 through the expansion valve 17. It is comprised so that it may flow into the main refrigerant | coolant flow path leading to.

  That is, a pipe 45 leading to the expansion valve 14 of the second refrigerant flow path is connected to one outlet of the flow divider 13, and the second flow of the intermediate heat exchanger 15 of the main refrigerant flow path is connected to the other outlet. A pipe 47 leading to the path 15B is connected. The main refrigerant flow path is the first compression element 11A of the compressor 11, the inside 16 of the sealed container, the second compression element 11B, the radiator 12, the flow divider 13, and the second flow path of the intermediate heat exchanger 15. 15B, an annular refrigerant flow path including an expansion valve 17 and an evaporator 18. The second refrigerant flow path refers to a refrigerant flow path from the flow divider 13 through the expansion valve 14 and the first flow path 15A of the intermediate heat exchanger 15 to the sealed container 16.

  On the other hand, in the present embodiment, the first refrigerant flow from the second refrigerant flow path and the refrigerant compressed by the first compression element 11 </ b> A of the compressor 11 merge in the sealed container 16 of the compressor 11. It is configured as follows. Therefore, in this embodiment, the sealed container 16 of the compressor 11 functions as a merging means for merging the two refrigerant flows. That is, the first refrigerant flow from the second refrigerant flow path and the refrigerant compressed by the first compression element 11A of the compressor 11 merge in the sealed container 16 and the merged refrigerant is second compressed. It is configured to be sucked into the element 11B.

  On the other hand, the expansion valve 14 is auxiliary throttle means for depressurizing the first refrigerant flow divided by the flow divider 13 and determines whether or not the first refrigerant flow is allowed to flow through the second refrigerant flow path. It functions as a valve device to control. The expansion valve 14 is connected to a controller C which will be described later, and the opening / closing operation is controlled by the controller C.

  The intermediate heat exchanger 15 is heat for exchanging heat between the first refrigerant flow after being depressurized by the expansion valve 14 flowing through the second refrigerant flow path and the second refrigerant flow flowing through the main refrigerant flow path. It is an exchanger. In the intermediate heat exchanger 15, a first flow path 15A in which the first refrigerant flow flows and a second flow path 15B in which the second refrigerant flow flows are arranged in a heat exchange manner. Furthermore, the intermediate heat exchanger 15 of the present embodiment is provided with the flow paths 15A and 15B so that the first refrigerant flow and the second refrigerant flow are opposed to each other in the intermediate heat exchanger 15. . By providing the intermediate heat exchanger 15 in this manner, the first refrigerant flow that is decompressed by the expansion valve 14 and flows into the first flow path 15A is the second refrigerant flow that flows through the second flow path 15B. Take heat away from. On the other hand, the second refrigerant stream is cooled by the first refrigerant stream. Thereby, the specific enthalpy of the refrigerant entering the evaporator 18 can be reduced.

  The outlet of the first flow path 15A of the intermediate heat exchanger 15 is connected to a sealed container of the compressor 11 and a pipe 46 having one end opened in the sealed container 16 of the compressor 11 is connected. The refrigerant discharged from the first flow path 15A is discharged from the pipe 46 into the sealed container 16 which is an intermediate pressure part of the compressor 11.

  As described above, the first refrigerant flow divided by the flow divider 13 is depressurized by the expansion valve 14, and then passes through the first flow path 15A of the intermediate heat exchanger 15 through the second flow path 15B. Heat exchanges with the flowing second refrigerant stream to evaporate. The first refrigerant flow evaporated into the refrigerant gas exits the first flow path 15A and enters the sealed container 16 of the compressor 11 where it merges with the refrigerant from the first compression element 11A. It will be sucked into the second compression element 11B. In the present embodiment, the two refrigerant flows are merged in the sealed container 16 of the compressor 11, but a merger is provided separately and the first refrigerant from the second refrigerant flow path is provided in the merger. The refrigerant flow and the refrigerant compressed by the first compression element 11A of the compressor 11 may be combined.

  On the other hand, the pipe 48 connected to the outlet of the second flow path 15B of the intermediate heat exchanger 15 is connected to the inlet of the expansion valve 17, and the pipe 50 exiting the expansion valve 17 is connected to the inlet of the evaporator 18. Yes. The expansion valve 17 is a main throttle means for reducing the pressure of the second refrigerant flow that flows through the main refrigerant flow path after being diverted by the flow divider 13. The expansion valve 17 is connected to the controller C, and the valve opening degree is controlled by the controller C. The evaporator 18 is an air-cooling type heat exchanger that takes heat from the air ventilated from the fan 18F and evaporates the refrigerant. The outlet of the evaporator 18 is connected to a refrigerant introduction pipe 40 that reaches the suction side of the first compression element 11 </ b> A that is a low-pressure portion of the compressor 11.

  As described above, the second refrigerant flow flowing through the main refrigerant circuit after being divided by the flow divider 13 flows to the evaporator 18 via the second flow path 15B of the intermediate heat exchanger 15 and the expansion valve 17. Thereafter, a cycle in which the current is diverted by the flow divider 13 again through the first compression element 11A of the compressor 11, the inside 16 of the sealed container, the second compression element 11B, and the heating unit 12A of the radiator 12 is repeated.

  Carbon dioxide is used as a refrigerant in the heat pump refrigerant circuit. The carbon dioxide refrigerant is compressed to the supercritical pressure by the second compression element 11B of the compressor 11 and sent to the heating unit 12A of the radiator 12. Water flowing through the heated portion 12B of the radiator 12 can be heated to a high temperature of + 90 ° C. or higher by the refrigerant flowing into the heating portion 12A in this supercritical state. The refrigerant discharge pipe 42 connected to the discharge side of the second compression element 11B of the compressor 11 of the heat pump refrigerant circuit is compressed by the second compression element 11B to become a high-temperature and high-pressure refrigerant gas. A temperature sensor TS1 is provided as discharge refrigerant temperature detection means for detecting the temperature of the refrigerant discharged from the machine 11.

  An intermediate heat exchanger inlet refrigerant temperature detecting means for detecting the temperature of the first refrigerant flow at the inlet of the intermediate heat exchanger 15 on the pipe 45 leading to the first flow path 15A of the intermediate heat exchanger 15. As an intermediate heat exchanger outlet refrigerant for detecting the temperature of the first refrigerant flow at the outlet of the intermediate heat exchanger 15 on the pipe 46 exiting from the first flow path 15A. A temperature sensor TS3 is provided as temperature detecting means. Each of these temperature sensors TS1, TS2, TS3 is connected to the controller C.

  The heat radiator 12 described above exchanges heat between the high-temperature and high-pressure refrigerant that has flowed out of the second compression element 11B of the compressor 11 that flows through the heat pump refrigerant circuit of the heat pump unit 10 and the water that flows through the hot water generation circuit of the hot water storage tank unit 30. It is a refrigerant | coolant versus water heat exchanger for. Specifically, in the heat radiator 12 of the embodiment, the heating unit 12A through which the refrigerant flows and the heated unit 12B through which the water of the hot water storage tank unit 30 flows are integrated in a heat exchange relationship. The flowing refrigerant and the flow of water flowing through the heated portion 12B are configured to face each other.

  The hot water storage tank unit 30 includes a hot water storage tank 31 for storing hot water. The hot water storage tank 31 is a tank having a vertically long cylindrical shape that can store hot water heated by heat exchange with the refrigerant in the radiator 12. A pipe 32 of the hot water generation circuit is connected to the lower end of the hot water storage tank 31. One end of the pipe 32 is open at the lower part in the hot water storage tank 31 and the other end is connected to the other side of the radiator 12 (that is, the water inlet side of the heated portion 12B). The water in the hot water storage tank 31 can be taken out. In addition, one end of the pipe 33 is connected to one side of the radiator 12 (that is, the water outlet side of the heated part 12B), and the pipe 33 stores hot water from one end connected to the heated part 12B of the radiator 12. The other end of the tank 31 is connected to the wall surface near the center in the height direction, and the other end is opened in the hot water storage tank 31.

  The pipe 32 includes a pump 32P for circulating the water in the hot water storage tank 31 in the hot water generating circuit, and a temperature sensor as an incoming water temperature detecting means for detecting the temperature of the water entering the radiator 12 (incoming water temperature). TS4 is provided. That is, the hot water generating circuit takes out the water in the lower part of the hot water storage tank 31 from the hot water storage tank 31 by the operation of the pump 32P, supplies it to the radiator 12, and then at the substantially central portion of the hot water storage tank 31 in the height direction. Is configured to return. The pump 32P and the temperature sensor TS4 are connected to the controller C.

  A hot water transfer circuit pipe 60 is connected to the upper end of the hot water storage tank 31 so that hot water stored in the upper part of the hot water storage tank 31 can be taken out from the pipe 60. The hot water transfer circuit is for transferring hot water in the hot water storage tank 31 to the use side heat exchanger 65. The use side heat exchanger 65 of the present embodiment is for using the heat of hot water in the hot water storage tank 31 conveyed through the piping of the hot water conveyance circuit for room heating. This heating mode can be applied to various types. For example, when used as an air conditioner (air conditioner), the use-side heat exchanger 65 constitutes a fan coil of an air conditioner, and when applied to floor heating, when used as a floor heating panel or panel heater. The use side heat exchanger 65 constitutes the heater panel. Moreover, the use side heat exchanger 65 is not limited to the above, but can be applied to other various heating devices.

  In this embodiment, two usage-side heat exchangers 65, 65 connected in parallel from the pipe 60 are provided, and the heat of hot water from the hot water storage tank 31 can be conveyed to the usage-side heat exchangers 65, 65, respectively. It is configured. That is, the pipe 60 has one end connected to the upper end of the hot water storage tank 31 as described above, opens in the water (hot water) stored in the upper part of the hot water storage tank 31, and the other end branches into two branches. One of the pipes 60 </ b> A is connected to the inlet of the one use side heat exchanger 65, and the other branched pipe 60 </ b> B is connected to the inlet of the other use side heat exchanger 65. The pipe 60 is provided with a pump 60 </ b> P for conveying the hot water in the hot water storage tank 31 to the use side heat exchangers 65 and 65.

  A pipe 62A is connected to the outlet of one use side heat exchanger 65, and a pipe 62B is connected to the outlet of the other use side heat exchanger 65. After these pipes 62A and 62B merge, they are connected to the lower side of the hot water storage tank 31, and one end of the pipe 62 is open in the lower water in the hot water storage tank 31.

  Furthermore, the heat pump hot water supply / room heating device H of the present embodiment is configured to be able to generate hot water for hot water supply using hot water stored in the hot water storage tank 31. Specifically, in the hot water storage tank 31, the heat exchanger 70 of the piping constituting the hot water supply circuit is disposed in the upper part where the hot water is stored so as to be able to exchange heat with the hot water in the upper part of the hot water storage tank 31. . That is, the hot water supply circuit is composed of a pipe 71 having one end connected to a water supply source such as tap water, and a midway part (heat exchange part) 70 of the pipe is arranged to be able to exchange heat with the hot water in the upper part of the hot water storage tank 31. Has been. And the piping 71 is extended outside the hot water storage tank 31 through the heat exchanger 70, and the other end is connected to a faucet such as a bath or a shower so that it can be used as domestic water. Thereby, in the process in which the water from the water supply source passes through the heat exchanger 70 in the hot water storage tank 31, the hot water stored in the upper part of the hot water storage tank 31 is heated, and the heated pipe 71 Hot water will be used for baths and showers.

  Furthermore, the hot water storage tank 31 of the present embodiment is provided with an electric heater 80 for heating the water stored in the hot water storage tank 31. The electric heater 80 of the embodiment is for heating hot water in the hot water storage tank 31 in addition to heating by heat exchange with the refrigerant in the radiator 12 in the hot water generating circuit described above to generate hot water. It is. In particular, in the electric heater 80 of this embodiment, the heating part is in the vicinity of one end opening of the pipe 61 of the hot water transfer circuit and in the vicinity of the heat exchange part 70 of the hot water supply circuit, that is, the hot water storage tank 31. It is immersed in the water above the inside. For this reason, since the water in the hot water storage tank 31 can be heated to a higher temperature by energizing the electric heater 80, the temperature of the hot water conveyed to the use side heat exchanger 65 can be increased, and The water flowing through the hot water supply circuit can be heated to a higher temperature. The electric heater 80 is connected to the controller C, and energization is controlled.

  Moreover, the heat pump hot water supply / room heating device H of the present invention includes an outside air temperature sensor TS5. The outside air temperature sensor TS5 is an outside air temperature detecting means for detecting the outside air temperature, and is connected to the controller C.

  Here, the controller C described above is a control device that controls the heat pump hot water supply / room heating device H. The controller C controls the operation of the compressor 11 of the heat pump unit 10 and the operations of the expansion valves 14 and 17 and controls the energization of the electric heater 80 of the hot water storage tank unit 30 and the operation of the pump 60P of the hot water transfer circuit. Yes.

  Next, the operation of the heat pump hot water supply / room heating apparatus H will be described with reference to FIG. 2 is a ph diagram (Mollier diagram) of the refrigerant flowing through the heat pump refrigerant circuit H. FIG. First, the compressor 11 and the pump 32P are started by the controller C.

  When the compressor 11 is started as described above, low-temperature and low-pressure refrigerant gas is sucked from the refrigerant introduction pipe 40 into the suction side of the first compression element 11A that is the low-pressure portion of the compressor 11. At this time, the refrigerant is in the state of point 1 shown in FIG. The refrigerant is compressed by the first compression element 11A to become an intermediate pressure refrigerant gas. The refrigerant in this case is in the state of point 2 shown in FIG. The refrigerant gas having the intermediate pressure exits from the first compression element 11A and is discharged into the sealed container 16. In this sealed container 16, the refrigerant merges with the first refrigerant flow from the pipe 46, resulting in a state of point 9 in FIG. 2. That is, the temperature of the refrigerant compressed by the first compression element 11A is lowered by the merge of the first refrigerant flow from the intermediate heat exchanger 15 whose temperature is lower than that of the refrigerant, and the state of point 2 in FIG. To point 9.

  Thereafter, the merged refrigerant is sucked into the suction side of the second compression element 11B, which is an intermediate pressure portion of the compressor 11, and compressed. The carbon dioxide refrigerant is compressed to the supercritical state as indicated by point 3 in FIG. 2 by the compression operation in the second compression element 11B. Then, the refrigerant is discharged from the compressor 11 in this state, and flows into the heating unit 12 </ b> A of the radiator 12 through the refrigerant discharge pipe 42.

  On the other hand, the low temperature water stored in the lower part of the hot water storage tank 31 is taken out from the hot water storage tank 31 by starting the pump 32P of the hot water generating circuit of the hot water storage tank unit 30. And the water which came out of the hot water storage tank 31 is suck | inhaled by the pump 32P on the piping 32, is discharged to the radiator 12 side, and flows into the to-be-heated part 12B of the radiator 12. FIG.

  On the other hand, the supercritical refrigerant that has flowed into the heating section 12A of the radiator 12 exchanges heat with water flowing through the heated section 12B provided in heat exchange with the heating section 12A, and dissipates heat. It becomes the state of the point 4 shown. At this time, the temperature of the refrigerant flowing into the radiator 12 rises to approximately + 100 ° C., and the water flowing through the heated portion 12B in the radiator 12 can be heated to a high temperature. The cycle of the water (hot water) heated by the refrigerant returning from the radiator 12 and returning to the hot water storage tank 31 through the pipe 33 is repeated.

  In this way, by operating the pump 32P, flowing the water in the hot water storage tank 31 through the hot water generation circuit and continuously exchanging heat with the refrigerant in the radiator 12, the hot water storage tank 31 has a high temperature. The hot water layer moves from the upper part to the lower part, and finally the entire hot water storage tank 31 can be filled with hot water.

  On the other hand, the refrigerant itself is cooled in the radiator 12, flows out of the radiator 12, and flows into the flow divider 13 through the pipe 44. The refrigerant is then split into a first refrigerant stream and a second refrigerant stream. One refrigerant flow (first refrigerant flow) divided by the flow divider 13 flows into the second refrigerant flow path. That is, the first refrigerant flow is depressurized in the process of passing through the expansion valve 14 via the pipe 45, and enters the state of point 7 shown in FIG. Next, the refrigerant discharged from the expansion valve 14 flows into the first flow path 15 </ b> A of the intermediate heat exchanger 15.

  On the other hand, the other refrigerant flow (second refrigerant flow) divided by the flow divider 13 passes through the second flow path 15B of the intermediate heat exchanger 15 via the pipe 47. In the intermediate heat exchanger 15, the first refrigerant flow flowing through the first flow path 15A and the second refrigerant flow flowing through the second flow path 15B exchange heat. That is, the first refrigerant flow that flows through the first flow path 15A is heated by the second refrigerant flow that flows through the second flow path 15B, and the state shown by the point 7 in FIG. 2 is changed to the point 8 in FIG. It becomes a state. On the other hand, the second refrigerant flow that flows through the second flow path 15A of the intermediate heat exchanger 15 exchanges heat with the first refrigerant flow that flows through the first flow path 15A, and dissipates heat. The state shown in FIG.

  As described above, in the intermediate heat exchanger 15, the second refrigerant flow flowing through the second flow path 15B is heat-exchanged with the first refrigerant flow flowing through the first flow path 15A, and the first refrigerant flow Can be cooled. In other words, heat exchange between the first refrigerant flow and the second refrigerant flow in the intermediate heat exchanger 15 can reduce the specific enthalpy of the second refrigerant flow entering the evaporator 18. Thereby, since the enthalpy difference in the evaporator 18 is expanded, the refrigeration effect can be enhanced. In addition, the first refrigerant flow that exits the first flow path 15 </ b> A of the intermediate heat exchanger 15 is sucked into the intermediate pressure portion of the compressor 11, whereby the first compression element 11 </ b> A that is the low pressure portion of the compressor 11. The amount of the second refrigerant flow sucked into the cylinder decreases, and the compression work for compressing from the low pressure to the intermediate pressure decreases. As a result, the compression power in the compressor 11 is reduced and the coefficient of performance is improved.

  Thereafter, the first refrigerant flow exiting the first flow path 15 </ b> A of the intermediate heat exchanger 15 flows into the sealed container 16 through the pipe 46. The first refrigerant flow in the sealed container 16 merges with the refrigerant compressed by the first compression element 11A and discharged into the sealed container 16, and is in a state indicated by a point 9 in FIG. That is, the temperature of the first refrigerant flow from the intermediate heat exchanger 15 rises due to the merge of the refrigerant from the first compression element 11A, which is higher than the first refrigerant flow, and the point 8 in FIG. From the state, the state becomes point 9.

  Then, the merged refrigerant is sucked into the suction side of the second compression element 11B and is compressed to be in a supercritical state (state of point 3 in FIG. 2). Then, the supercritical refrigerant is discharged from the compressor 11 and enters the heating unit 12 </ b> A of the radiator 12 through the refrigerant discharge pipe 42. Then, after passing through the heating unit 12A, heat is exchanged with the water flowing through the heated unit 12B to dissipate heat (state of point 4 in FIG. 2), and then the cycle of returning to the flow divider 13 through the pipe 44 is repeated.

  On the other hand, after radiating heat in the second flow path 15B of the intermediate heat exchanger 15, the second refrigerant flow exiting the second flow path 15B passes through the expansion valve 17 via the pipe 48. In the process of passing through the expansion valve 17, the pressure of the refrigerant decreases, and the state of point 6 shown in FIG. 2 is obtained. Thereafter, the refrigerant flows into the evaporator 18 and exchanges heat with air (outside air) blown by the fan 18F. That is, the refrigerant evaporates by absorbing heat from the air (outside air) blown to the evaporator 18, and the state of point 1 shown in FIG.

  At this time, as described above, the refrigerant (second refrigerant flow) entering the evaporator 18 is the refrigerant cooled by the first refrigerant flow in the intermediate heat exchanger 15. That is, the intermediate heat exchanger 15 exchanges heat between the first refrigerant flow and the second refrigerant flow, so that the refrigerant changes from the state indicated by the point 4 in FIG. The specific enthalpy of the entering second refrigerant flow can be reduced. Thereby, since the state of the refrigerant | coolant of the evaporator 18 inlet_port | entrance can be made into the point 6 of FIG. 2, the enthalpy difference in the evaporator 18 can be expanded and the freezing effect can be heightened.

  The refrigerant evaporated in the evaporator 18 then exits the evaporator 18 and repeats a cycle of being sucked from the refrigerant introduction pipe 40 into the suction side of the first compression element 11 </ b> A that is the low pressure portion of the compressor 11.

  In a split cycle (two-stage compression single-stage expansion intermediate cooling cycle) in which such a refrigerant is divided into two flows, the second refrigerant flow that flows through the main refrigerant flow path is expanded by the expansion valve 14 that flows through the second refrigerant flow path. Of course, the temperature cannot be lower than that of the first refrigerant flow after being decompressed. It is also impossible to heat the first refrigerant flow in the second refrigerant flow path higher than the refrigerant temperature before branching.

  Here, in a conventional cycle (that is, a cycle including only the main refrigerant flow path), the opening degree of the expansion valve 17 is controlled based on the refrigerant temperature discharged from the compressor 11. Specifically, when the valve opening degree of the expansion valve 17 is reduced, the refrigerant temperature discharged from the compressor 11 increases, and when the valve opening degree is increased, the discharge refrigerant temperature decreases. For this reason, a discharge temperature target value is set such that the discharge refrigerant temperature discharged from the compressor 11 becomes a predetermined value, and the controller C controls the valve opening degree of the expansion valve 17 so as to approach the target value. Was.

  By the way, in the split cycle, the effect of cooling the second refrigerant flow by the first refrigerant flow in the intermediate heat exchanger depends on the amounts of the first refrigerant flow and the second refrigerant flow flowing through the intermediate heat exchanger. It will be. For this reason, it is necessary to control the expansion valve 14 in addition to the control of the expansion valve 17.

That is, when the flow rate of the first refrigerant flow flowing through the second refrigerant flow path is increased, the refrigerant specific enthalpy at the outlet of the second flow path 15B of the intermediate heat exchanger 15 in the main refrigerant flow path is reduced. Specifically, the amount of heat exchange between the first refrigerant flow and the second refrigerant flow in the intermediate heat exchanger 15 will be described with reference to FIG. 2. The amount of heat exchange at the inlet of the second flow path 15B of the intermediate heat exchanger 15 is described below. The refrigerant flow of No. 2 is in the state of point 4 (this enthalpy is h4), the second refrigerant flow at the outlet of the second flow path 15B is in the state of point 5 (this enthalpy is h5), and the first The first refrigerant flow at the inlet of the first flow path 15A is in the state of point 7 (this ethane rupee is set as h7) and at the outlet is in the state of point 8 (this enthalpy is set as h8). Assuming that the flow rate of the first refrigerant flow flowing through R1 is R1, and the flow rate of the second refrigerant flow flowing through the second flow path 15B is R2, the amount of heat exchange is
(H4-h5) × R2 = (h8−h7) × R1 (1)

  Here, as shown in FIG. 3, if the flow rate of the first refrigerant flow through the second refrigerant flow path is large, the second refrigerant flow can be sufficiently cooled by the intermediate heat exchanger 15. As indicated by point 5, the temperature of the second refrigerant flow at the outlet of the second flow path 15B is lowered, and the specific enthalpy can be reduced. In this case, since the flow rate of the first refrigerant flow is large, the specific enthalpy of the first refrigerant flow at the outlet of the first flow path 15A is also low as indicated by point 8 in FIG. Further, if the flow rate of the first refrigerant flow becomes excessive, the first refrigerant flow cannot be sufficiently heated by the second refrigerant flow in the intermediate heat exchanger 15, and the first heat flow at the outlet of the intermediate heat exchanger 15 is not achieved. The refrigerant flow 1 becomes a two-phase mixed state in which gas and liquid are mixed. In this case, the pressure of the refrigerant discharged from the compressor rises abnormally, or the temperature of the refrigerant discharged from the compressor drops abnormally. Furthermore, since the refrigerant in the wet state (two-phase state in which gas and liquid are mixed or in the liquid state) is sucked into the intermediate pressure portion of the compressor, the compressor 11 may be liquid compressed and damaged.

  On the other hand, as shown in FIG. 4, when the flow rate of the first refrigerant flow flowing through the second refrigerant flow path decreases, the temperature of the first refrigerant flow at the outlet of the intermediate heat exchanger 15 increases as indicated by point 8 in FIG. Get higher. In this case, since the heat dissipation effect of the second refrigerant flow flowing through the second flow path 15B in the intermediate heat exchanger 15 is reduced, the temperature of the second refrigerant flow is also increased as indicated by point 5 in FIG. Therefore, the performance improvement effect by the split cycle is also reduced.

  On the other hand, in such a split cycle, when the valve opening of the expansion valve 14 is large and the first refrigerant flow is large, the relationship between the expansion valve 17 and the discharge temperature may be reversed as shown in FIG. is there. FIG. 12 is a Mollier diagram in this case (when the relationship between the expansion valve 17 and the discharge temperature is reversed as shown in FIG. 11). In FIG. 12, a solid line is a Mollier diagram when the opening degree of the expansion valve 17 is large, and a broken line is a Mollier chart when the opening degree is small. That is, when the valve opening of the expansion valve 17 is reduced, the refrigerant temperature discharged from the compressor 11 rises. However, when the flow rate of the first refrigerant flow is large as described above, the expansion valve 17 is opened. If the degree is reduced, there may be a reverse relationship such that the refrigerant temperature discharged from the compressor 11 decreases. This is because, when the flow rate of the first refrigerant flow through the second refrigerant flow path is relatively large and the valve opening of the expansion valve 17 is reduced, the flow rate of the first refrigerant flow through the second refrigerant flow path is reduced. As a result, the specific enthalpy of the first refrigerant flow flowing from the second refrigerant flow path to the second compression element 11B, which is the intermediate pressure portion of the compressor 11, is reduced, the temperature is decreased, or the wetness is increased. It is because it will be in a state.

  Thus, when the relationship between the valve opening degree of the expansion valve 17 serving as the main throttle means and the refrigerant discharge temperature of the compressor 11 is reversed, the high pressure is abnormally increased or the refrigerant temperature discharged from the compressor 11 is abnormal. Problems such as lowering tend to occur. That is, in the conventional control of the expansion valve 17, when the discharge temperature is lower than a predetermined value, the opening degree of the expansion valve 17 is reduced, so that the discharge refrigerant temperature is further lowered and the high pressure is further increased. End up. As a result, the difference between the discharge temperature and the target value of the discharge temperature increases, that is, the temperature difference increases in a direction lower than the target value, so that the valve opening degree of the expansion valve 17 is controlled to be further reduced. . As a result, the temperature of the discharged refrigerant is further lowered, and there is a problem in that the high pressure is abnormally increased.

  Further, when the incoming temperature of the water flowing through the radiator 12 is low, the refrigerant temperature at the outlet of the radiator 12 is close to the saturation temperature corresponding to the pressure of the intermediate pressure portion of the compressor 11. In this case, as shown in FIG. 5, the temperature difference between the refrigerant temperature before branching in the flow divider 13 and the first refrigerant flow after decompression by the expansion valve 14 becomes small. For this reason, the effect of cooling the second refrigerant flow in the intermediate heat exchanger 15 is small, and the first refrigerant flow may return to the compressor 11 in a two-phase mixed state in which gas and liquid are mixed or in a liquid state. There is.

  In such a case, the performance improvement effect by the split cycle is small, and inconveniences such as abnormal high pressure and liquid compression are likely to occur. Therefore, it is preferable to perform the operation by a normal cycle.

  Furthermore, the pressure of the intermediate pressure portion of the compressor 11 includes the evaporation pressure (outside air temperature) in the evaporator 18, the discharge pressure (outside air temperature, the temperature of water that exchanges heat with the refrigerant in the radiator 12, and the hot water storage tank 31. The target temperature of the hot water to be stored) and the volume ratio of the compressor 11 also vary. The broken line in FIG. 6 shows the case where only the outside air temperature is raised from the operation indicated by the solid line, that is, the wavy line in FIG. 6 uses the same compressor (that is, the compressor with the same volume ratio) as the solid line in FIG. It is the Mollier diagram at the time of driving | running by raising only an outside temperature on the conditions which made the water temperature which flows into the radiator 12 the same. Thus, if the incoming temperature of the water flowing into the radiator 12 with the same compressor is also the same, it can be seen that the intermediate pressure increases as the outside air temperature increases.

  In this way, even when the outside air temperature is high, an abnormally high pressure is likely to occur, so that operation by split cycle is not preferable.

  Therefore, when the outside air temperature is high as described above and when the incoming water temperature of the radiator 12 is low, the performance improvement effect by the split cycle is small and stable operation is difficult, so the split cycle operation is performed. Instead, it is desirable to operate in a normal cycle.

  Therefore, in the present invention, the controller C controls the valve openings of the expansion valve 14 and the expansion valve 17 of the heat pump refrigerant circuit based on the outputs of the temperature sensors TS1, TS2, TS3TS4, and TS5 described above. First, the controller C of this embodiment controls the valve opening of the expansion valve 14 so that the temperature of the refrigerant discharged from the compressor 11 rises when the valve opening of the expansion valve 17 is reduced. Specifically, the controller C controls the opening degree of the expansion valve 17 based on the output of the temperature sensor TS1 so that the refrigerant temperature discharged from the compressor 11 becomes a predetermined discharge temperature target value, and the temperature sensor TS2. And the valve of the expansion valve 14 so that the temperature difference of the first refrigerant flow at the outlet and inlet of the first flow path 15A of the intermediate heat exchanger 15 becomes a predetermined temperature difference target value based on the output of the temperature sensor TS3. Control the opening. Further, the controller C reduces the valve opening degree of the expansion valve 17 when the temperature of the refrigerant discharged from the compressor 11 is lower than the discharge temperature target value, expands it when it is higher, and sets the outlet of the intermediate heat exchanger 15. When the temperature difference of the first refrigerant flow at the inlet is smaller than the temperature difference target value, the opening of the expansion valve 14 is reduced, and when it is larger, the opening is increased. FIG. 10 shows a Mollier diagram when the expansion valve 14 and the expansion valve 17 are controlled as in the present invention. In FIG. 10, a solid line is a Mollier diagram when the opening degree of the expansion valve 17 is large, and a broken line is a Mollier chart when the opening degree of the expansion valve 17 is small.

  Thus, according to the present invention, the temperature sensor TS1 that detects the temperature of the refrigerant discharged from the compressor 11, and the temperature sensor TS2 that detects the temperature of the first refrigerant flow at the inlet of the intermediate heat exchanger 15; And a temperature sensor ST3 for detecting the temperature of the first refrigerant flow at the outlet of the intermediate heat exchanger 15, and discharged from the compressor 11 by the controller C based on the outputs of the temperature sensors ST1 to TS3. The valve opening degree of the expansion valve 17 is controlled so that the refrigerant temperature becomes a predetermined discharge temperature target value, and the temperature difference between the first refrigerant flow at the outlet and the inlet of the intermediate heat exchanger is the predetermined temperature difference target value. Specifically, the valve opening of the expansion valve 17 is controlled so that the valve opening of the expansion valve 17 is specifically set when the temperature of the refrigerant discharged from the compressor 11 is lower than the discharge temperature target value as in this embodiment. When shrinking and high And the opening degree of the expansion valve 14 is reduced when the temperature difference between the first refrigerant flow at the outlet and the inlet of the intermediate heat exchanger 15 is smaller than the target temperature difference value, and is increased when the temperature difference is larger. Thus, the first refrigerant flow and the second refrigerant flow can be set to optimum flow rates. Thereby, the efficiency improvement effect by a split cycle can be exhibited.

  In particular, the valve opening of the expansion valve 17 is controlled by controlling the valve opening of the expansion valve 14 so that the temperature of the refrigerant discharged from the compressor 11 rises when the valve opening of the expansion valve 17 is reduced. When the degree is reduced, it is possible to avoid inconvenience that the relationship between the expansion valve 17 and the discharge temperature is reversed such that the discharge refrigerant temperature of the compressor 11 is lowered.

  Furthermore, the controller C supplies the heat to the radiator 12 detected by the temperature sensor TS4 based on the outputs of the temperature sensor TS4 and the outside air temperature sensor TS5 provided in the pipe 32 on the inlet side of the heated portion 12B of the radiator 12. When the incoming water temperature is high or when the outside air temperature detected by the outside air temperature sensor TS5 is high, the above-described temperature difference target value is expanded. Specifically, the controller C of this embodiment has a table shown in FIG. Then, a temperature difference target value is determined based on the table of FIG. 7 from the outside air temperature detected by the temperature sensor TS5 and the incoming water temperature detected by the temperature sensor TS4, and at the outlet and inlet of the intermediate heat exchanger 15. The valve opening degree of the expansion valve 14 is controlled so that the temperature difference of the first refrigerant flow becomes the temperature difference target value.

  For example, when the incoming water temperature detected by the temperature sensor TS4 is + 40 ° C. and the outside air temperature detected by the outside air temperature sensor TS5 is −7 ° C., the controller C uses the table of FIG. 7) (corresponding to the target SP temperature difference shown in FIG. 7). The controller C then detects the temperature of the first refrigerant flow at the outlet of the intermediate heat exchanger 15 detected by the temperature sensor TS3 (the outlet temperature of the intermediate heat exchanger 15) T8 and the intermediate detected by the temperature sensor TS2. The valve opening degree of the expansion valve 14 is controlled so that the difference (T8−T7) from the temperature of the first refrigerant flow at the inlet of the heat exchanger 15 (inlet temperature of the intermediate heat exchanger 15) T7 approaches + 5 ° C. To do. On the other hand, when the outside air temperature is −7 ° C. and the incoming water temperature rises to + 50 ° C., the controller C determines the temperature difference target value to be 8 ° C. from the table of FIG. Then, the controller C controls the expansion valve 14 so that the difference (T8−T7) between the outlet temperature T8 and the inlet temperature T7 approaches + 8 ° C.

  On the other hand, when the incoming water temperature is + 50 ° C. and the outside air temperature rises to + 2 ° C., the controller C determines the temperature difference target value to 9 ° C. according to the table of FIG. The controller C then detects the difference between the outlet temperature T8 of the intermediate heat exchanger 15 detected by the temperature sensor TS3 and the inlet temperature T7 of the intermediate heat exchanger 15 detected by the temperature sensor TS2 (T8−T7). The valve opening degree of the expansion valve 14 is controlled so as to approach + 9 ° C.

  As described above, when the incoming water temperature is high or the outside air temperature is high, the temperature difference target value is expanded as described above, whereby the first refrigerant flow and the second refrigerant flow are set to the optimum flow rates. can do. Thereby, the inconvenience that the relationship between the opening degree of the expansion valve 17 and the discharge temperature is reversed can be avoided, and the cycle performance can be improved.

  Further, when the performance improvement effect by the split cycle is small and stable operation is difficult, the operation by the split cycle is not performed. Specifically, the controller C has a small performance improvement effect due to the split cycle, and it is difficult to perform stable operation, that is, when the temperature of water entering the radiator 12 detected by the temperature sensor TS4 is lower than a predetermined value. Alternatively, when the outside air temperature detected by the outside air temperature sensor TS5 is higher than a predetermined value, the expansion valve 14 is fully closed and the first refrigerant flow is not allowed to flow.

  In this embodiment, as shown in FIG. 8, when the incoming water temperature detected by the temperature sensor TS4 is lower than the predetermined value Win, which is + 15 ° C., the controller C fully closes the expansion valve 14 and operates in a split cycle. Shall not be performed. Specifically, when the incoming water temperature is 14.9 ° C. or lower, which is lower than + 15 ° C., the controller C fully closes the expansion valve 14 regardless of the outside air temperature. Thereby, a refrigerant | coolant stops flowing into a 2nd refrigerant | coolant flow path. That is, the refrigerant flows only in the main refrigerant flow path, and the operation in the normal cycle is performed.

  On the other hand, when the incoming water temperature becomes + 15 ° C. or higher, the controller C determines opening / closing of the expansion valve 14 based on the outside air temperature detected by the outside air temperature sensor TS5. In this embodiment, as shown in FIG. 8, the predetermined value Tg is set to + 10 ° C., and the opening and closing of the expansion valve 14 is controlled by the controller C depending on whether it is higher or lower than this value Tg (+ 10 ° C.). Specifically, when the incoming water temperature detected by the temperature sensor ST4 is + 15 ° C. or higher and the outside air temperature detected by the outside air temperature sensor TS5 is higher than + 10 ° C., the controller C turns the expansion valve 14 all on. Closed. Thereby, since a refrigerant | coolant does not flow into a 2nd refrigerant | coolant flow path, the driving | operation by the normal cycle in which a refrigerant | coolant flows only into a main refrigerant | coolant flow path comes to be performed.

  On the other hand, when the incoming water temperature is + 15 ° C. or higher and the outside air temperature is lower than + 10 ° C., the controller C cancels the fully closed state of the expansion valve 14 and the expansion valve 14 by each temperature sensor described above. Start the opening control. Thereby, the operation by the split cycle is performed.

  Thus, when the incoming water temperature is lower than a predetermined value (+ 15 ° C. in the present embodiment), or when the outside air temperature is higher than a predetermined value (+ 10 ° C. in the present embodiment), the controller C causes all the expansion valves 14 to move. Since the first refrigerant flow is not caused to flow through the second refrigerant flow path, the operation is performed in a normal cycle in which the refrigerant circulates only in the main refrigerant flow path. As a result, it is possible to perform a normal cycle operation under conditions where stable operation is difficult in the split cycle.

  In general, the present invention makes it possible to realize a stable and highly efficient operation of the heat pump hot water supply / room heating device H.

  In the above embodiment, as shown in FIGS. 2 to 6, the first refrigerant flow entering the intermediate heat exchanger 15 is in a two-phase mixed state (two-phase region) in which gas and liquid are mixed. explained. Thus, when the first refrigerant flow decompressed by the expansion valve 14 is in a two-phase region, the temperature is set so that the refrigerant of the first refrigerant flow at the outlet of the intermediate heat exchanger 15 is in a gas state. A difference target value (corresponding to the first temperature difference target value) needs to be determined. On the other hand, as shown in FIG. 9, the 1st refrigerant | coolant flow which enters into the intermediate heat exchanger 15 may be in a supercritical state. In FIG. 9, point 4 indicates the state of the refrigerant in the flow divider 13, and point 7 indicates the state of the first refrigerant flow after being decompressed by the expansion valve 14. In this case, the first refrigerant flow remains in the supercritical state even after being decompressed by the expansion valve 14.

  Thus, when the first refrigerant flow entering the intermediate heat exchanger 15 is in a supercritical state, the controller C indicates that the refrigerant of the first refrigerant flow at the inlet of the intermediate heat exchanger is in the two-phase region. In this case, a temperature difference target value (second temperature difference target value) larger than the temperature difference target value (first temperature difference target value) is set and the valve of the expansion valve 14 approaches the temperature difference target value. The opening degree shall be controlled.

  When the incoming water temperature is high or when the outside air temperature is high, the intermediate pressure becomes high, and a state exceeding the supercritical pressure as described above may occur. In such a case, the relationship between the opening degree of the expansion valve 17 and the discharge temperature is obtained by increasing the target temperature difference value so that the refrigerant flow rate ratio between the first refrigerant flow and the second refrigerant flow is appropriate. The inconvenience of reverse rotation can be avoided, and stable and highly efficient operation can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram of the heat pump type hot water supply and heating apparatus of one Example to which this invention is applied (Example 1). FIG. 2 is a Mollier diagram of the heat pump hot water supply and heating apparatus of FIG. 1. It is an example of the Mollier diagram when the flow rate of the first refrigerant flow is large. It is an example of the Mollier diagram when the flow rate of the first refrigerant flow is small. It is an example of the Mollier diagram in the case where the refrigerant temperature at the radiator outlet is close to the saturation temperature corresponding to the pressure of the intermediate pressure portion of the compressor in the heat pump hot water supply and heating device. It is an example of the Mollier diagram which shows the change of the refrigerant | coolant state accompanying the change of outside temperature. It is an example of the table of the temperature difference target value by the outside temperature and the incoming water temperature which the control apparatus of a heat pump type hot water supply and heating apparatus has. It is a figure which shows the opening / closing operation | movement of the auxiliary | assistant throttle means based on an incoming water temperature and external temperature. (Example 2) which is an example of the Mollier diagram in case the 1st refrigerant | coolant flow which enters into an intermediate heat exchanger will be in a supercritical state. It is a Mollier diagram in the case of controlling the auxiliary aperture means and the main aperture means as in the present invention. It is a figure which shows the relationship between the conventional high pressure and discharge temperature, and the opening degree of the main throttle means. FIG. 12 is an example of a Mollier diagram when the relationship between the main throttle means and the discharge temperature is reversed in FIG. 11.

C controller (control device)
H Heat pump hot water supply and heating device 10 Heat pump unit 11 Compressor 11A First compression element 11B Second compression element 12 Radiator (refrigerant to water heat exchanger)
12A Heating part 12B Heated part 13 Separator 14 Expansion valve (auxiliary throttle means)
15 intermediate heat exchanger 15A first flow path 15B second flow path 16 inside sealed container 17 expansion valve (main throttle means)
18 Evaporator 30 Hot Water Storage Tank Unit 31 Hot Water Storage Tank 32, 33 Piping (Pipe for Hot Water Generation Circuit)
40 Refrigerant introduction pipe 44, 45, 46, 47, 48, 50 Piping (refrigerant piping)
42 Refrigerant discharge pipe 60, 62 Piping 65 User side heat exchanger 70 Heat exchanger 71 Piping 80 Electric heater TS1, TS2, TS3, TS4 Temperature sensor TS5 Outside air temperature sensor

Claims (6)

A heat pump refrigerant circuit configured to include a compressor, a refrigerant-to-water heat exchanger, and an evaporator, and a hot water storage tank capable of storing hot water, and the water in the hot water storage tank is converted into the refrigerant-to-water heat exchanger In a heat pump hot water supply and heating device that stores hot water in the hot water storage tank,
The heat pump refrigerant circuit includes the compressor, the refrigerant-to-water heat exchanger, an auxiliary throttle means, an intermediate heat exchanger, a main throttle means, and the evaporator, and from the refrigerant-to-water heat exchanger The refrigerant that has exited is divided into two flows, the first refrigerant stream is passed through the auxiliary throttle means to the first flow path of the intermediate heat exchanger, and the second refrigerant stream is passed through the intermediate heat exchanger. After flowing through the second flow path, by flowing through the main throttle means to the evaporator, heat exchange between the first refrigerant flow and the second refrigerant flow in the intermediate heat exchanger, Causing the refrigerant exiting the evaporator to be sucked into the low pressure portion of the compressor, causing the first refrigerant flow from the intermediate heat exchanger to be sucked into the intermediate pressure portion of the compressor, and
Discharge refrigerant temperature detection means for detecting the temperature of the refrigerant discharged from the compressor;
Intermediate heat exchanger inlet refrigerant temperature detection means and intermediate heat exchanger outlet refrigerant temperature detection means for detecting the temperature of the first refrigerant flow at the inlet and outlet of the intermediate heat exchanger;
And a control device for controlling the valve openings of the main throttle means and the auxiliary throttle means based on the outputs of the temperature detection means, and the control device reduces the valve opening of the main throttle means when the valve opening degree of the main throttle means is reduced. A heat pump type hot water supply and heating device , wherein the opening degree of the auxiliary throttle means is controlled so that the temperature of the refrigerant discharged from the compressor rises . The control device controls the valve opening degree of the main throttle means based on the output of the discharge refrigerant temperature detection means so that the temperature of the refrigerant discharged from the compressor becomes a predetermined discharge temperature target value, and Based on the outputs of the intermediate heat exchanger inlet refrigerant temperature detection means and the intermediate heat exchanger outlet refrigerant temperature detection means, the temperature difference of the first refrigerant flow at the outlet and inlet of the intermediate heat exchanger is a predetermined temperature difference target value. The heat pump hot water supply / room heating apparatus according to claim 1, wherein the valve opening degree of the auxiliary throttle means is controlled so that The control device reduces the valve opening of the main throttle means when the temperature of the refrigerant discharged from the compressor is lower than the discharge temperature target value, expands it when it is higher, and the outlet of the intermediate heat exchanger The valve opening degree of the auxiliary throttle means is reduced when the temperature difference between the first refrigerant flow at the inlet and the inlet is smaller than the temperature difference target value, and is increased when the temperature difference is larger. Heat pump hot water heater / heater. When the refrigerant of the first refrigerant flow at the inlet of the intermediate heat exchanger is in a two-phase region, the control device determines the target temperature difference value of the first refrigerant flow at the outlet of the intermediate heat exchanger. When the first temperature difference target value at which the refrigerant enters a gas state and the refrigerant in the first refrigerant flow at the inlet of the intermediate heat exchanger is in the supercritical region, the temperature difference target value is set to the first temperature. The heat pump hot water supply / room heating device according to claim 2 or 3, wherein the second temperature difference target value is larger than the difference target value . An incoming water temperature detecting means for detecting an incoming water temperature entering the refrigerant-to-water heat exchanger, and an outside air temperature detecting means for detecting an outside air temperature,
The said control apparatus expands the said temperature difference target value, when the said incoming water temperature is high based on the output of these temperature detection means, or when the said external temperature is high. 3. A heat pump hot water supply / room heating apparatus according to 3. 6. The control device according to claim 5, wherein the controller does not flow the first refrigerant flow when the incoming water temperature is lower than a predetermined value or when the outside air temperature is higher than a predetermined value. Heat pump hot water heater / heater.

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