JP2009186115A - Refrigerating cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve performance by improving a refrigerating capacity in an evaporator of a refrigerating cycle device, in particular, to improve the refrigerating capacity by improving a radiating capacity of the refrigerating cycle device using carbon dioxide as the refrigerant. <P>SOLUTION: This refrigerating cycle device comprises a brine tank 24 for storing brine, a refrigerant-brine heat exchanger 30 for exchanging heat between the refrigerant from a radiator 2 and the brine in the brine tank 24, a brine circulating circuit 20 for supplying the brine at a lower portion in the brine tank 24 to the heat exchanger 30, and returning the brine to an upper portion in the brine tank 24, a pump 26 for circulating the brine between the brine tank 24 and the heat exchanger 30 by the brine circulating circuit 20, and a heat exchanger 22 and a fan 22F as cooling means for cooling the brine in the brine tank 24, and a controller C controls an operation of a compressor 1 and the pump 26, and vertically forms a temperature boundary layer of the brine in the brine tank 24. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a refrigeration cycle apparatus including a refrigerant circuit using carbon dioxide as a refrigerant.

  Conventionally, in this type of refrigeration cycle apparatus, a refrigeration cycle is constituted by a compressor, a radiator, an evaporator, and the like. In this case, the refrigerant compressed by the compressor dissipates heat at the radiator, and after being depressurized by the throttle means, evaporates at the evaporator, and the ambient air is cooled by evaporation of the refrigerant at this time. (For example, refer to Patent Document 1).

  In recent years, the use of HCFC-based refrigerants containing chlorine such as R22 that have been used in conventional refrigeration cycle devices has been regulated due to environmental problems and the like, and natural refrigerants are an alternative to such conventional refrigerants. Attempts have been made to use carbon dioxide (see, for example, Patent Document 2).

  FIG. 10 is an overall configuration diagram of a conventional refrigeration cycle apparatus using a carbon dioxide refrigerant. The refrigeration cycle apparatus 100 of FIG. 10 is used as, for example, an air conditioner (air conditioner) for air conditioning a room. The refrigeration cycle apparatus 100 includes a refrigerant circuit including a compressor 1, a radiator 2 (gas cooler), an expansion valve 4 as a decompression unit, an evaporator 5, a four-way valve 7 as a refrigerant flow switching unit, and the like. In this case, the evaporator 5 is disposed as a heat exchanger on the use side so that the room can be air-conditioned (for example, installed in the room). During the cooling or dehumidifying operation, the refrigerant discharged from the compressor 1 flows into the radiator 2, and the four-way valve 7 is switched so as to return to the compressor 1 through the expansion valve 4 and the evaporator 5 in order. On the other hand, during the heating operation, after the refrigerant discharged from the compressor 1 flows into the evaporator 5, the four-way valve 7 is switched so as to return to the compressor 1 through the expansion valve 4 and the radiator 2 in order.

Specifically, the operation during the cooling operation will be described. First, the refrigerant compressed by the compressor 1 flows into the radiator 2 through the four-way valve 7 and dissipates heat. Next, the refrigerant reaches the expansion valve 4, is decompressed in the process of passing through the expansion valve 4, and then flows into the evaporator 5. Therefore, the refrigerant evaporates by exchanging heat with the surrounding air. At this time, air is cooled by the endothermic action of the refrigerant. Thereby, the room can be cooled. In addition, the refrigerant evaporated in the evaporator 5 repeats a cycle in which the refrigerant leaves the evaporator 5 and is sucked into the compressor 1 through the four-way valve 7.
JP 2005-233451 A JP 2007-205596 A

  By the way, it is known that the carbon dioxide refrigerant is a refrigerant having a high and low pressure difference, and the critical pressure is low and the high pressure of the refrigerant cycle is likely to be in a supercritical state due to compression. In the refrigeration cycle apparatus using such a carbon dioxide refrigerant, the heat source temperature on the radiator side is high (that is, the outside air temperature exchanging heat with the refrigerant in the radiator is high), for example, in a state where the outside air temperature is high such as midsummer. In this case, the refrigerant cannot sufficiently dissipate heat, so that the refrigerant temperature at the outlet of the radiator also rises. As a result, the specific enthalpy at the evaporator inlet increases and the refrigeration capacity is significantly reduced. In this case, in order to ensure the refrigerating capacity, it is necessary to increase the high pressure, which causes a disadvantage that the compression power increases and the coefficient of performance (COP) decreases.

  FIG. 11 is a diagram illustrating the relationship between the outside air temperature and the coefficient of performance of a refrigeration cycle apparatus using carbon dioxide refrigerant. As shown in FIG. 11, when the outside air temperature is + 30 ° C., the capacity can be secured without increasing the high pressure, so that the compression power can be suppressed and a relatively high coefficient of performance (COP) can be obtained. However, when the outside air temperature rises, the refrigerant temperature at the radiator outlet also increases, the specific enthalpy at the evaporator inlet increases, and the refrigeration capacity decreases significantly. It is clear that the high pressure needs to be increased, and as a result, the compression power increases and the coefficient of performance (COP) decreases. Thus, in a refrigeration cycle apparatus using a carbon dioxide refrigerant, the refrigeration capacity is extremely deteriorated in a situation where the outside air temperature is high, so that the refrigeration cycle apparatus can be applied to an air conditioner, a refrigerator, etc. and put into practical use. It was difficult.

  The present invention has been made to solve the problems of the related art, and aims to improve the refrigeration capacity in the evaporator of the refrigeration cycle apparatus using a carbon dioxide refrigerant, thereby improving the performance. To do. In particular, it aims to improve the coefficient of performance by improving the deterioration of ability at high outside temperatures.

  The refrigeration cycle apparatus of the present invention includes a compressor, a radiator, and an evaporator, and includes a refrigerant circuit that uses carbon dioxide as a refrigerant. The brine tank stores brine and the refrigerant outlet side of the radiator A refrigerant-brine heat exchanger for exchanging heat between the refrigerant discharged from the radiator and the brine in the brine tank, and the lower brine in the brine tank are supplied to the refrigerant-brine heat exchanger, A brine circulation circuit for returning to the upper part in the brine tank, a pump for circulating the brine between the brine tank and the refrigerant-brine heat exchanger by the brine circulation circuit, and cooling the brine in the brine tank A cooling means and a controller for controlling the operation of the compressor and the pump, the controller controlling the operation of the compressor and the pump; , And forming a thermal boundary layer of the brine to the top or bottom area of the brine tank.

  In the refrigeration cycle apparatus according to the second aspect of the present invention, in the above invention, the controller sets a target temperature of the refrigerant and the brine that can form a temperature boundary layer of the brine above and below the brine tank based on an index based on the outside air temperature. The operation of the compressor and the pump is controlled based on the temperature.

  A refrigeration cycle apparatus according to a third aspect of the present invention is the refrigeration cycle apparatus according to the present invention, wherein the brine is water in each of the above-mentioned inventions, and includes a water supply means capable of supplying water to the lower part in the brine tank, and a hot water extraction unit capable of extracting hot water from the upper part in the brine tank The controller is characterized in that when the temperature boundary layer of the brine in the brine tank is lowered, water is supplied to the lower part in the brine tank by the water supply means, and hot water is taken out from the upper part in the brine tank from the hot water takeout part.

  A refrigeration cycle apparatus according to a fourth aspect of the present invention comprises the water supply means for supplying water into the brine circulation circuit leading to the refrigerant-brine heat exchanger in which the brine is water in the first or second aspect of the invention. It is characterized by.

  A refrigeration cycle apparatus according to a fifth aspect of the invention is characterized in that, in the invention according to any one of the first to fourth aspects, the cooling means cools the brine in the brine tank by air cooling or water cooling.

  A refrigeration cycle apparatus according to a sixth aspect of the present invention is the refrigeration cycle apparatus according to any of the first to fourth aspects of the present invention, wherein the cooling means uses the endothermic action generated by the heat pump device that constitutes the hot water supply device. It is characterized by cooling.

  According to the present invention, a brine tank that stores brine, and a refrigerant-to-brine heat exchanger that is provided on the refrigerant outlet side of the radiator and for exchanging heat between the refrigerant discharged from the radiator and the brine in the brine tank. And a brine circulation circuit for supplying the brine in the lower part of the brine tank to the refrigerant-brine heat exchanger and then returning it to the upper part in the brine tank, and the brine circulation circuit between the brine tank and the refrigerant-to-brine heat exchanger. And a cooling means for cooling the brine in the brine tank, and a controller for controlling the operation of the compressor and the pump. The controller controls the operation of the compressor and the pump. Since a brine temperature boundary layer is formed above and below the brine tank, a high temperature bridging is formed above the brine tank. , It is possible to accumulate brine low temperatures down. Thus, the low temperature brine stored under the temperature boundary layer is passed through the refrigerant-to-brine heat exchanger and used for heat dissipation of the refrigerant so that the refrigerant discharged from the radiator can be further radiated. become. In particular, in the refrigerant-to-brine heat exchanger, a temperature boundary layer of brine is formed above and below in the brine tank, and the low-temperature brine stored below the temperature boundary layer is passed through the refrigerant-to-brine heat exchanger. Cooling of the refrigerant can be performed efficiently and continuously.

  As a result, even when the refrigerant temperature at the radiator outlet becomes high, such as when the outside air temperature is high, the temperature of the refrigerant exiting the radiator by the brine in the refrigerant-to-brine heat exchanger can be lowered. A sufficient enthalpy difference in the evaporator can be secured without increasing the pressure. Accordingly, since the refrigeration capacity can be improved without increasing the compression power, the coefficient of performance is improved, and the decrease in the cooling capacity when using the carbon dioxide refrigerant can be prevented.

  In particular, the controller sets the target temperature of the refrigerant and the brine that can form the temperature boundary layer of the brine in the upper and lower sides of the brine tank from the index based on the outside air temperature, and compresses based on the target temperature. If the operation of the machine and the pump is controlled, the temperature boundary layer of the brine can be easily formed above and below in the brine tank.

  Further, as in the invention of claim 3, the brine is water, and includes a water supply means capable of supplying water to the lower part of the brine tank, and a hot water extraction unit capable of taking out hot water from the upper part of the brine tank, When the temperature boundary layer of the brine drops, water is supplied to the lower part of the brine tank by water supply means, and if hot water is taken out from the upper part of the brine tank from the hot water outlet, cold water is newly supplied to the lower part of the brine tank. As a result, the temperature of the water in the brine tank can be lowered. In particular, since hot hot water that does not contribute to cooling of the refrigerant can be taken out from the upper part of the brine tank from the hot water outlet, the temperature of the water in the brine tank can be actively lowered, and the temperature boundary in the brine tank can be reduced. Layers can also be maintained.

  Further, in the invention of claim 1 or claim 2, if the brine is water as in claim 4 and provided with a water supply means for supplying water into the brine circulation circuit leading to the refrigerant-brine heat exchanger, the water supply means Of cold water can be passed directly to the refrigerant to brine heat exchanger to cool the refrigerant.

  Furthermore, in each of the above inventions, if the cooling means cools the brine in the brine tank by air cooling or water cooling as in the invention of claim 5, the temperature of the brine in the brine tank can be lowered. The cooling capacity of the refrigerant in the anti-brine heat exchanger can be maintained.

  In the invention of claim 1 to claim 4, if the cooling means as in the invention of claim 6 cools the brine in the brine tank using the endothermic action generated by the heat pump device constituting the hot water supply device, It becomes possible to effectively use the cold energy that has been conventionally discarded in the heat pump operation.

  The present invention is made in order to solve the problem that the refrigerating capacity in the evaporator is remarkably lowered due to the rise in the refrigerant temperature at the radiator outlet when the carbon dioxide refrigerant is used. The purpose of improving the refrigerating capacity of the evaporator and improving the performance of the refrigeration cycle apparatus using carbon dioxide refrigerant is provided in the brine tank for storing brine and the refrigerant outlet side of the radiator, and is discharged from the radiator. A refrigerant-brine heat exchanger for exchanging heat between the refrigerant and the brine in the brine tank, and a brine for returning the lower brine in the brine tank to the refrigerant-brine heat exchanger and then returning it to the upper part in the brine tank A circulation circuit, a pump for circulating brine between the brine tank and the refrigerant-to-brine heat exchanger by the brine circulation circuit, a cooling means for cooling the brine in the brine tank, and the operation of the compressor and pump A controller for controlling the operation of the compressor and pump by the controller, and in the brine tank It was achieved by forming the thermal boundary layer of the brine down. Hereinafter, embodiments of the refrigeration cycle apparatus of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an overall configuration diagram of an embodiment of a refrigeration cycle apparatus to which the present invention is applied. The refrigeration cycle apparatus S of the present embodiment is used as an air conditioner (air conditioner) that performs indoor air conditioning, and includes a refrigerant circuit 10, a brine circulation circuit 20, a refrigerant that flows through the refrigerant circuit 10, and a brine circulation circuit. 20 is constructed from a refrigerant-to-brine heat exchanger 30 for heat exchange with brine flowing through 20. In the embodiment, the refrigeration cycle apparatus S is described as applied to an air conditioner (air conditioner) that performs indoor air conditioning. However, the refrigeration cycle apparatus S of the present invention is not limited to an air conditioner, but is applied to a cooling apparatus such as a refrigerator. Even it is effective.

The refrigerant circuit 10 is a refrigerant circuit in which carbon dioxide (CO ₂ ) is used as a refrigerant and the high pressure side becomes a supercritical pressure. The compressor 1, the radiator 2, the refrigerant-to-brine heat exchanger 30, and the decompression means The expansion valve 4 and the evaporator 5 are connected by piping. That is, the four-way valve 7 is connected to the refrigerant discharge pipe 41 connected to the discharge side of the compressor 1. The four-way valve 7 is a refrigerant flow path switching means of the refrigerant circuit 10 and is configured to be able to switch the refrigerant flow path according to the operating condition of the air conditioner. That is, when indoor cooling or dehumidifying operation is selected, the refrigerant discharged from the compressor 1 is caused to flow through the pipe 42 leading to the radiator 2 and the refrigerant from the pipe 46 connected to the evaporator 5. The refrigerant flow path is switched from the four-way valve 72 so that the refrigerant flows through the refrigerant introduction pipe 40 connected to the suction side of the compressor 1. On the other hand, when indoor heating operation is selected, the refrigerant discharged from the compressor 1 is caused to flow through the refrigerant pipe 46 connected to the evaporator 5 and the refrigerant from the radiator 2 is caused to flow through the refrigerant introduction pipe 40. Thus, the refrigerant flow path is switched. That is, it goes without saying that in the heating operation, the evaporator 5 functions as a radiator and the radiator 2 functions as an evaporator.

  The refrigerant pipe 42 described above is connected to one side of the radiator 2 (corresponding to the refrigerant inlet side in the cooling operation), and will be described later on the other side (corresponding to the refrigerant outlet side of the radiator 2 during the cooling operation). A refrigerant pipe 43 leading to the refrigerant-to-brine heat exchanger 30 is connected. A pipe 44 extending to the expansion valve 4 is connected to the side of the refrigerant-to-brine heat exchanger 30 opposite to the side to which the refrigerant pipe 43 is connected. And the expansion valve 4 and the evaporator 5 are connected by the refrigerant | coolant piping 45, and the refrigerant | coolant piping 46 which reaches the four-way valve 7 is connected to the opposite side to the expansion valve 4 of the evaporator 5 as mentioned above. Yes.

  The refrigerant-to-brine heat exchanger 30 described above is a heat exchanger for exchanging heat between the refrigerant discharged from the radiator 2 and the brine circulating in the brine circulation circuit 20. The heat exchanger 30 is configured such that the refrigerant and the brine flow oppositely.

  Here, the operation at the time of the cooling operation in the refrigerant circuit 10 will be described. First, the refrigerant gas compressed by the compressor 1 and having a high temperature and high pressure flows into the radiator 2 from the refrigerant discharge pipe 41 through the four-way valve 7 and the refrigerant pipe 42, and radiates heat by exchanging heat with the surrounding air there. Then, the refrigerant exiting the radiator 2 flows into the refrigerant-to-brine heat exchanger 30 via the refrigerant pipe 43, and further exchanges heat with the brine to further dissipate heat. The refrigerant whose temperature has decreased by further releasing heat in the refrigerant-to-brine heat exchanger 30 is then depressurized by the expansion valve 4 through the refrigerant pipe 44 and then flows into the evaporator 5 through the refrigerant pipe 45.

  In this evaporator 5, the refrigerant takes heat from the surrounding air and evaporates. The ambient air is cooled by the endothermic action of the refrigerant. Thereafter, the refrigerant repeats a cycle of being sucked into the compressor 1 from the refrigerant introduction pipe 40 through the refrigerant pipe 46 and the four-way valve 7.

  On the other hand, in the brine circulation circuit 20, a tubular cycle is configured by connecting a refrigerant-to-brine heat exchanger 30, a heat exchanger 22, a brine tank 24, and a pump 26 in order. That is, the pipe 50 exiting the refrigerant-to-brine heat exchanger 30 is connected to the inlet of the heat exchanger 22, and the pipe 52 connected to the outlet of the heat exchanger 22 is connected to the upper end of the brine tank 24 described later. ing. A pipe 54 is connected to the lower end of the brine tank 24 so that hot water stored in the lower part of the brine tank 24 can be taken out from the pipe 54.

  The pipe 54 connected to the lower end of the brine tank 24 leads to the pump 26, and the pipe 56 connected to the outlet of the pump 26 is connected to the refrigerant-brine heat exchanger 30 to constitute such a tubular cycle. Has been.

  The heat exchanger 22 is the cooling means of the present invention for cooling the brine in the brine tank 24. The cooling means of the embodiment operates a fan 22F that is arranged so that the outside air can be passed through the heat exchanger 22, and the outside air blown to the heat exchanger 22 and the inside of the brine tank 24 that flows through the heat exchanger 22. This is an air-cooling type cooling means for exchanging heat with brine and cooling the brine with outside air. In this case, the fan 22F is operated when the compressor 1 is stopped, that is, when the cooling operation is not performed, and is operated in a time zone in which the outside air temperature is lowest, for example, at night. A specific driving operation will be described in detail later. The pump 26 circulates brine between the brine tank 24 and the refrigerant-to-brine heat exchanger 30 by the brine circulation circuit 20.

  The brine tank 24 described above is a tank for storing brine. As described above, a pipe 56 is connected to the lower end of the brine tank 24, and the brine stored in the lower part of the brine tank 24 can be taken out from the pipe 56. A pipe 52 is connected to the upper end, and the brine circulated through the circuit 20 from the pipe 52 returns to the upper part of the brine tank 24. That is, the brine circulation circuit 20 takes out the lower brine in the brine tank 24 from the brine tank 24 by operating the pump 26 and supplies it to the refrigerant-brine heat exchanger 30. It is configured to return.

  In this embodiment, the brine circulating in the brine circulation circuit 20 is water. However, in the present invention, the brine is not limited to the water of the embodiment, and any fluid can be used as long as it can circulate in the brine circulation circuit 20 and can exchange heat with the refrigerant in the refrigerant-brine heat exchanger 30. For example, it is also effective to use coolant (such as automobile coolant) as the brine.

  On the other hand, the brine tank 24 includes means for supplying water to the brine tank 24 and a hot water outlet. The water supply means of this embodiment is composed of a water supply pipe 57 and a water supply valve 57V, and one end of the water supply pipe 57 is connected to a water supply source for tap water or the like (tap water in this embodiment) and the other end. Is connected to the lower part of the brine tank 24. And tap water can be supplied to the lower part in the brine tank 24 through the water supply piping 57 by opening operation of the water supply valve 57V. The hot water take-out section is constituted by a take-out pipe 58 connected above the brine tank 24 and brine take-out means (for example, take-out pump) such as a pump (not shown). That is, one end of the extraction pipe 58 is connected to the upper part in the brine tank 24, and one end thereof is opened in the brine stored in the upper part of the tank 24. The brine above the tank 24 can be taken out by the operation of the take-out pump. This extraction pipe 58 is connected to a faucet of a water supply such as a washing machine, a toilet, and a dining room, and is configured to be usable as household water.

  Further, in the brine tank 24 of the present embodiment, a temperature sensor TS3 for detecting the temperature of the brine (water in the embodiment) stored in the lower portion of the brine tank 24 is installed and connected to the controller C. .

  The controller C is a control unit that controls the refrigeration cycle apparatus S. Specifically, the controller C controls the operation of the compressor 1 of the refrigerant circuit 10 and the operation of the pump 26 of the brine circulation circuit 20 based on the refrigerant temperature, the outside air temperature, and the like in the refrigerant circuit 10. In particular, in the present invention, the controller C controls the operation of the compressor 1 and the pump 26 so that the boundary layer of the brine temperature is formed above and below the brine tank 24.

  The controller C of the embodiment sets the target temperature of the refrigerant and the brine that can form the temperature boundary layer of the brine in the upper and lower sides of the brine tank 24 by the index created based on the outside air temperature, and the compressor based on the target temperature 1 and the operation of the pump 26 are controlled. Specifically, the controller C predicts the temperature of the day, for example, the maximum temperature (corresponding to the index based on the outside temperature of the present invention) based on a database built in beforehand or data such as weather information input from the outside. .

  Then, the target temperature Tset of the refrigerant and the target temperature Twset of the brine are set so that the predicted maximum temperature becomes a temperature at which the brine temperature boundary layer can be formed above and below in the brine tank 24. The operation of the compressor 1 and the pump 26 is controlled so as to reach the target temperature. In the present embodiment, a temperature sensor TS1 for detecting the temperature of the refrigerant exiting the radiator 2 is installed in the refrigerant pipe 42 on the outlet side of the radiator 2 and on the inlet side of the refrigerant-to-brine heat exchanger 30. To do. Further, a temperature sensor TS <b> 2 that detects the temperature of the brine that has exited the refrigerant-to-brine heat exchanger 30 is installed in the pipe 50 on the outlet side of the refrigerant-to-brine heat exchanger 30 in the brine circulation circuit 20. Each temperature center TS1, TS2 is connected to a controller C. The controller C controls the operation of the compressor 1 and the pump 26 so that the refrigerant temperature detected by the temperature sensor TS1 becomes the heat radiation point Tset and the brine temperature detected by the temperature sensor TS2 becomes Twset. And

  In the present embodiment, a database built in advance, or a forecast of the highest temperature of the day based on data such as weather information input from the outside is used as an index based on the outside air temperature. The outside air temperature is estimated from the air temperature after passing through the radiator 2, and the target temperature of the refrigerant and the brine that can form the temperature boundary layer of the brine in the top and bottom of the brine tank 24 is set from the outside air temperature based on this target temperature. Thus, the present invention is also effective for controlling the operation of the compressor 1 and the pump 26.

  Next, the control operation of the refrigeration cycle apparatus S during the cooling operation with the above configuration will be described using the flowchart shown in FIG. First, when the power of the refrigeration cycle apparatus S is turned on and the cooling operation is selected, the controller C sets the target refrigerant pair in step S1 based on the temperature (maximum temperature) of the day predicted in step S0. The heat radiation point Tset of the refrigerant in the brine heat exchanger 30 is set. Next, in step S2, the heat release temperature Twset of the brine that has passed through the refrigerant-to-brine heat exchanger 30 of the brine circulation circuit 20 is set from Tset set in step S1. In this case, the heat radiation temperature Twset is set in consideration of heat loss in the heat exchanger 30. In this embodiment, a value obtained by subtracting a constant α related to the heat loss of the heat exchanger 30 from the heat radiation point Tset is set as the heat radiation temperature Twset. Furthermore, the controller C determines the high pressure control pressure Pset based on the heat radiation point Tset of S1 in step S3.

  As described above, when the target temperatures Tset, Twset and the control pressure Pset are determined in steps S1 to S3, the controller C next determines the liquid level of the brine tank 24 in step S4, that is, in the brine tank 24. The water level of the brine stored in is detected (tank liquid level monitoring shown in step S4 in FIG. 2). That is, the controller C determines whether or not the inside of the brine tank 24 is full. If it is determined that the brine tank 24 is full, the process proceeds directly to step S6.

  On the other hand, if it is determined in step S4 that the inside of the brine tank 24 is not full, the process moves to step S5, and water supply to the brine tank 24 is executed (tap water injection shown in step S5 in FIG. 2). Specifically, the controller C opens the water supply valve 57V of the water supply pipe 57 in step S5. Thereby, the tap water from the water supply source is supplied to the lower part of the brine tank 24 through the water supply pipe 57. When the predetermined water level is reached, the controller C fully closes the water supply valve 57V and proceeds to the next step S6. Thereby, supply of the tap water to the brine tank 24 is stopped, and it transfers to the control operation of following step S6.

  Next, in step S6, the controller C compares the temperature of the outside air with the temperature of the water in the brine tank 24, and determines whether or not to perform heat exchange between the refrigerant and the brine in the refrigerant-to-brine heat exchanger 30. Determine. In this case, when the temperature of the water in the lower part of the brine tank 24 detected by the temperature sensor TS3 is higher than the outside air temperature, the controller C uses the refrigerant after the heat is exchanged with the outside air in the radiator 2 and radiated. The temperature of the brine from the brine tank 24 flowing to the refrigerant-to-brine heat exchanger 30 becomes higher, or the refrigerant cannot be dissipated, so the operation using the brine tank using the brine circulation circuit 20 is not performed. Is desirable.

  Therefore, the controller C determines whether or not the brine temperature detected by the temperature sensor TS3 in step S6 is larger than the value obtained by adding the constant β related to the heat loss of the predetermined heat exchanger 30 to the outside air temperature. When the temperature of the brine detected by the temperature sensor TS3 is larger than the value obtained by adding the constant β to the outside air temperature, it is determined that the refrigerant discharged from the radiator 2 can be cooled using the brine. Then, the process proceeds to the next step S7, and the brine tank operation for exchanging heat between the brine and the refrigerant is started. In this case, the controller C starts the compressor 1 and the pump 26 in step S7.

  Furthermore, the controller C controls the rotation speed of the fan 2F of the radiator 2 in step S8. Specifically, in addition to the operation of the compressor 1, in addition to the operation of the fan 2F, the refrigerant temperature at the outlet of the radiator 2 (corresponding to the gas cooler shown in step S8 in FIG. 2) detected by the temperature sensor TS1 becomes Tset. Control the number of revolutions.

  Further, in step S9, the operation of the pump 26 of the brine circulation circuit 20 is controlled so that the temperature of the brine leaving the heat exchanger 30 detected by the temperature sensor TS2 becomes Twset. Since the operation of the refrigerant in the refrigerant circuit 10 during the cooling operation is as described above, the description thereof is omitted. On the other hand, when the pump 26 is driven as described above, the low-temperature brine stored in the lower part of the brine tank 24 is taken out from the tank 24, and the refrigerant-brine heat exchange is performed from the pipe 56 through the pipe 54 and the pump 26 in order. Flows into the vessel 30. The brine is heated by exchanging heat with the refrigerant flowing through the refrigerant-to-brine heat exchanger 30 to remove the heat of the refrigerant. At this time, as described above, in the refrigerant-to-brine heat exchanger 30, the refrigerant and the brine are caused to flow in opposite directions, so that the heat exchange capability between the refrigerant and the brine is improved.

  The brine heated by the refrigerant in the refrigerant-to-brine heat exchanger 30 then repeats a cycle of returning to the upper part of the brine tank 24 from the pipe 52 via the pipe 50 and the heat exchanger 22. In addition, since the fan 22F of the heat exchanger 22 is stopped during the cooling operation, the brine is not radiated in the heat exchanger 22 and remains heated in the refrigerant-to-brine heat exchanger 30. It is returned to the upper part of the brine tank 24.

  On the other hand, the controller C executes water supply control to the brine tank 24 in addition to the water supply control in steps S4 and S5 described above. That is, although the temperature of the water in the original brine tank 24 is low, the brine temperature in the brine circulation circuit 20 rises due to heat exchange with the refrigerant, and the temperature boundary layer of the brine in the brine tank 24 falls. Thus, when the low-temperature brine temperature stored in the lower part of the brine tank 24 rises, the low-temperature brine cannot flow through the refrigerant-to-brine heat exchanger 30. As a result, there arises a disadvantage that the heat dissipation capability of the refrigerant in the heat exchanger 30 is lowered.

  For this reason, in order to prevent the heat dissipation capability of the refrigerant in the heat exchanger 30 from being lowered, when the brine temperature stored in the lower part of the brine tank 24 is equal to or higher than a predetermined temperature, the inside of the brine tank 24 shown in step S10 A water supply operation for lowering the brine temperature is performed. Specifically, the controller C normally stops the extraction pump (that is, when the brine temperature in the lower part of the brine tank 24 detected by the temperature sensor TS3 is lower than a predetermined temperature). In this state, the brine in the upper part of the brine tank 24 does not flow out from the extraction pipe 58.

  On the other hand, when the temperature boundary layer of the brine in the brine tank 24 is lowered, that is, in this embodiment, when the brine temperature in the lower part of the brine tank 24 detected by the temperature sensor TS3 becomes a predetermined temperature or more, the take-out pump is started. Then, the high temperature brine stored in the upper part of the brine tank 24 is taken out of the brine tank 24 from the takeout pipe 58. At this time, the water supply valve 57V is opened to supply low-temperature tap water to the lower part of the brine tank 24. As a result, low-temperature water is supplied to the lower part of the brine tank 24, so that the temperature of the brine flowing through the heat exchanger 30 can be lowered, and the refrigerant is effectively cooled by the heat exchanger 30. Such heat dissipation capability can be maintained.

  In addition, after performing water supply control of step S10, the controller C returns to step S4, and repeatedly performs the control operation | movement of step S4 thru | or step S10 mentioned above. On the other hand, when the temperature of the brine detected by the temperature sensor TS3 in step S6 is equal to or less than the value obtained by adding the constant β to the outside air temperature, the refrigerant discharged from the radiator 2 can be cooled using the brine. It judges that it cannot be performed, it progresses to step S11, and the conventional cooling operation without a brine tank is performed. Thereafter, the controller C returns to step S4 and repeatedly executes the control operations of steps S4 to S10 described above.

  Here, a case where the refrigeration cycle apparatus S is actually operated with the brine temperature in the lower part of the brine tank 24 set to + 25 ° C., the capacity of the brine tank 24 set to 200 L, and the heat loss of the heat exchanger 30 set to 3 ° C. will be described. FIG. 3 is a ph diagram (Mollier diagram) of the refrigerant in the refrigerant circuit 10 in this case, and FIG. 4 is a diagram showing a relationship between the refrigerant temperature and entropy. 3 and FIG. 4, the solid line indicates the case where the operation using the brine tank is performed, and the broken line indicates the case where the operation is performed without the tank, that is, the refrigerant / brine heat exchanger 30 performs heat exchange between the refrigerant and the brine. The operation of the conventional refrigeration cycle apparatus when not performed is shown. A is the state of the refrigerant at the inlet of the compressor 1, B is the outlet of the compressor 1, C is the outlet of the radiator 2, D is the outlet of the refrigerant to brine heat exchanger 30 (that is, the inlet of the expansion valve 4), and E is the expansion valve 4 outlets (evaporator 5 inlet) and E ′ respectively indicate the state of the refrigerant at the conventional expansion valve 4 outlet (evaporator 5 inlet).

  As shown in FIGS. 3 and 4, the specific enthalpy and entropy at the inlet of the evaporator 5 can be lowered by radiating the refrigerant in the refrigerant-to-brine heat exchanger 30. As a result, the entropy difference and the entropy difference in the evaporator 5 can be sufficiently obtained.

  When considering an air conditioner with a cooling capacity of 4.7 kW, if the temperature at the outlet of the radiator 2 at + 40 ° C. is cooled to + 30 ° C. by cooling with the brine tank 24, the entropy difference can be increased by 1.48 kW. When converted into a coefficient (COP), the value of 3.1 in the conventional operation can be increased to 4.6 according to the present invention.

  Therefore, the refrigerating capacity in the evaporator 5 can be improved without increasing the high pressure. As a result, the refrigeration capacity can be ensured by suppressing the compression power, so that the coefficient of performance can be improved.

  As described above in detail, the operation of the compressor 1 and the pump 26 is controlled to form a brine temperature boundary layer above and below in the brine tank 24, so that a high temperature brine above the brine tank 24, Brine having a low temperature can be accumulated below. As a result, the low-temperature brine stored below the temperature boundary layer is caused to flow through the refrigerant-to-brine heat exchanger 30 to further dissipate the refrigerant from the radiator 2 of the refrigerant circuit 30 that flows through the heat exchanger 30. be able to. In particular, a brine temperature boundary layer is formed above and below the brine tank 24 as in the present invention, and a low temperature brine stored below the temperature boundary layer is caused to flow to the coolant-to-brine heat exchanger 30, thereby The heat radiation of the refrigerant in the anti-brine heat exchanger 30 can be performed efficiently and continuously.

  As a result, even under circumstances where the outside air temperature is high, the specific enthalpy at the inlet of the evaporator 5 can be lowered and the enthalpy difference in the evaporator 5 can be ensured without increasing the high pressure. The refrigeration capacity of 5 can be improved. In particular, by applying the present invention, the refrigeration capacity can be ensured without increasing the high pressure, so that an increase in compression power can be avoided and the coefficient of performance (COP) can be improved. It becomes like this. Thereby, it becomes possible to prevent the cooling capacity and efficiency of the refrigeration cycle apparatus S using the carbon dioxide refrigerant from decreasing.

  In particular, the target temperature Tset and Twset of the brine and the brine that can form the temperature boundary layer of the brine and the target temperature Tset and Twset are set based on the target temperature Tset and Twset based on the index based on the outside air temperature as in this embodiment. By controlling the operation of the compressor 1 and the pump 26, the brine temperature boundary layer can be easily formed above and below the brine tank 24.

  Furthermore, when the temperature boundary layer of the brine in the brine tank 24 is lowered, water is supplied to the lower part of the brine tank 24 by the water supply means, and the hot water is taken out from the upper part of the brine tank 24 from the hot water take-out part. Since cold water can be newly supplied to the lower part, the temperature of the water in the brine tank 24 can be lowered. In particular, by extracting hot water from the upper part of the brine tank 24 from the hot water outlet, only hot water in the upper part of the brine tank can be taken out, so that the temperature boundary layer in the brine tank 24 can be maintained.

  By the way, in the brine circulation circuit 20 of the refrigeration cycle apparatus S of the present embodiment, the heat exchanger 22 and the fan 22F are provided as cooling means for cooling the brine in the brine tank 24 as described above. The fan 22F of the cooling means is connected to the controller C, and the cooling operation of the brine in the heat exchanger 22 is controlled by the controller C. That is, since the outside air is not ventilated to the heat exchanger 22 when the fan 22F is stopped, the brine circulating in the brine circulation circuit 20 returns to the brine tank 24 without radiating heat in the heat exchanger 22. On the other hand, when the fan 22F is operated by the controller C, the outside air is ventilated to the heat exchanger 22, so that the brine flowing through the heat exchanger 22 and the outside air ventilated exchange heat. In this case, the controller C cools the brine in the brine tank 24 using the cooling means when the compressor 1 of the refrigerant circuit 10 is stopped, that is, when the cooling operation is stopped. This is because if the fan 22 is operated during the cooling operation to cool the brine, the cooled brine returns to the upper part of the brine tank 24, and the above-described temperature boundary layer collapses.

  Furthermore, when using an air-cooling type cooling means as in this embodiment, it goes without saying that the temperature of the outside air blown to the heat exchanger 22 affects the heat radiation of the brine. In other words, it is most desirable to operate the fan 22F during a time period when the temperature of the outside air is low to exchange heat with the brine. FIG. 5 is data showing a maximum temperature and a minimum temperature for one month in midsummer (August) in a certain city. As shown in FIG. 5, it can be seen that the difference between the daytime maximum temperature and the nighttime minimum temperature is at least about 6 ° C. to 8 ° C. It is also known that there is a temperature difference of about 10 ° C. between the daily maximum and minimum temperatures in rural areas. Accordingly, the pump 26 and the fan 22F are operated at night when the outside air temperature is the lowest in the day and the cooling operation is not performed, and the brine in the brine tank 24 is allowed to flow through the brine circulation circuit 20. It is apparent that the brine can be cooled most effectively by the cooling means by exchanging the heat of the brine passing through the heat exchanger 22 with the outside air.

  Next, the brine cooling operation will be specifically described with reference to FIG. In FIG. 6, arrows indicate the flow of brine in the cooling operation. First, the controller C starts the pump 26 and the fan 22F at the night when the outside air temperature is the lowest and when the compressor 1 is not performing the cooling operation. As a result, the brine in the brine tank 24 is taken out from the lower portion of the tank 24 and passes through the refrigerant 54 and the brine heat exchanger 30 via the pipe 54 and the pump 26. During the operation, the compressor 1 of the refrigerant circuit 10 is stopped, and there is no circulation of the refrigerant in the refrigerant circuit 10, so that heat exchange between the brine and the refrigerant is not performed in the refrigerant-to-brine heat exchanger 30.

  Then, the brine that has exited the refrigerant-to-brine heat exchanger 30 flows into the heat exchanger 22 via the pipe 54, and exchanges heat with the outside air that is ventilated by the fan 22F. At this time, the brine from inside the brine tank 24 heated in the daytime cooling operation is cooled by taking heat away from the outside air by exchanging heat with the outside air having a low temperature. Thereafter, the brine that has exited the heat exchanger 22 returns to the upper part of the brine tank 24 and is repeatedly discharged from the lower part to the pipe 50. In the brine cooling operation, since the brine cooled by releasing heat to the air in the heat exchanger 22 returns to the upper part in the brine tank 24, the temperature boundary layer in the brine tank 24 is destroyed, and finally The entire brine in the brine tank 24 becomes low temperature.

  In this way, when the cooling operation is stopped, the brine in the brine tank 24 is flowed to the brine circulation circuit 20 to operate the cooling means, so that the brine in the brine tank 24 heated by the cooling means in the daytime cooling operation is discharged. Can be cooled. In particular, when air-cooled cooling means is used as in this embodiment, it is possible to efficiently cool the brine by exchanging heat with the outside air by operating the cooling means at night when the outside air is at the lowest temperature. Become. In this case, the temperature boundary layer in the brine tank 24 is destroyed. However, since the brine cooling operation of the present embodiment is performed when the cooling operation is stopped, the cooling of the brine is performed without adversely affecting the cooling operation. And the entire brine in the brine tank 24 can be cooled.

  In the first embodiment described above, as shown in FIG. 6, an air-cooling cooling unit that cools brine by flowing outside air to the heat exchanger 22 using a fan 22F is used. For example, the brine in the brine tank 24 may be cooled by a water cooling method. Furthermore, the air-cooling type cooling means and the water-cooling type cooling means shown in FIG. 6 may be provided. FIG. 7 shows an example of the brine circulation circuit 20 in this case. In FIG. 7, the same reference numerals as those in FIGS. 1 and 6 denote the same or similar effects or actions, and the description thereof is omitted here.

  The brine circulation circuit 20 of the present embodiment shown in FIG. 7 includes two cooling means, that is, an air-cooling cooling means similar to FIG. 6 and a water-cooling cooling means. In this case, since the air-cooling cooling means is the same as that described in the first embodiment, the description thereof will be omitted, and the water-cooling cooling means will be described. This water-cooling type cooling means is arranged in the lower part of the brine tank 24 so that the middle part (the heat exchange part 62) can exchange heat with the brine below the temperature boundary layer in which the brine having a low temperature is stored. It is comprised from the installed heat exchange piping 60 and the valve apparatus which is not shown in figure. One end of the heat exchanging pipe 60 is connected to a water supply source such as tap water, and the other end is connected to a faucet of a water supply such as a washing machine, a toilet or a dining room, and is configured to be usable as household water. ing.

  In this case, when the valve device of the heat exchange pipe 60 is opened, tap water is supplied from a water supply source connected to one end of the pipe 60. The tap water exchanges heat with the brine stored in the lower part of the brine tank 24 in the process of passing through the heat exchange section 62 of the heat exchange pipe 60 disposed in the brine tank 24 described above. Since the water-cooling type cooling means of the present embodiment is configured to cool the low-temperature brine stored in the lower part of the brine tank 24 as described above, the temperature boundary layer of the brine in the brine tank 24 is reduced. Since there is no disturbance, the brine in the brine tank 24 can be cooled even during the operation of the compressor 1, that is, during the cooling operation.

  For example, when the brine temperature detected by the temperature sensor TS <b> 3 in the brine tank 24 rises to a predetermined temperature, the controller C opens the valve device of the heat exchange pipe 60 and causes the tap water to flow through the heat exchange pipe 60. At this time, the tap water exchanges heat with the brine in the brine tank 24 in the process of passing through the heat exchanging unit 62 arranged to be able to exchange heat with the brine in the brine tank 24. Thereby, the brine can throw away heat to the brine flowing through the heat exchanging unit 62.

  Thus, the brine in the brine tank 24 heated by the cooling operation can be directly cooled by the air cooling type cooling means. In particular, since the temperature of tap water is about 10 ° C. lower than the air temperature (outside air temperature), it is possible to effectively cool even during the daytime when the cooling operation is performed. Also, at night when cooling operation is not performed, it is possible to efficiently cool the brine by exchanging heat with the outside air by operating the air cooling method described above without using the water cooling method. It becomes. Alternatively, if the brine is cooled by both the water-cooling type cooling means and the air-cooling type cooling means, the cooling can be performed more efficiently in a shorter time.

  Next, a refrigeration cycle apparatus S according to another embodiment of the present invention will be described with reference to FIG. In the refrigeration cycle apparatus S of the present embodiment shown in FIG. 8, a part of the refrigerant circuit of the heat pump apparatus 80 of the hot water supply apparatus 70 and a part of the brine circulation circuit 20 are arranged in a heat exchange manner. The (heat exchanger 92) serves as a cooling means for cooling the brine. That is, the cooling means of the refrigeration cycle apparatus S of the present embodiment cools the brine in the brine tank 24 using the endothermic action generated by the heat pump apparatus 80 that constitutes the hot water supply apparatus 70.

  In FIG. 8, since the entire configuration of the refrigeration cycle apparatus S is the same as that described in the first embodiment, only the configuration different from the first embodiment will be mainly described here. The hot water supply device 70 in FIG. 8 is configured by a heat pump device 80 and a hot water supply tank unit 90. The heat pump device 80 includes a refrigerant cycle (refrigerant circuit) configured by sequentially connecting a compressor 81, a heat exchanger 82, an expansion valve 83, an electromagnetic valve 84, and an evaporator 85 by piping. Also, the piping exiting the expansion valve 83 is branched into two branches, one of which is connected to the electromagnetic valve 84 described above, and the other is sequentially passed through the electromagnetic valve 86 and the heat exchanger 92 as the cooling means of this embodiment. It is connected to a pipe connected to the inlet side of the compressor 81.

  The heat exchanger 82 is provided with a water pipe of a hot water supply tank unit 90 (described later) disposed in heat exchange relation with the refrigerant pipe of the heat pump device 80. In the heat exchanger 82, the refrigerant and water flowing through the pipes respectively. Are arranged so that the flow of the countercurrent flows. A pipe 93 of a water circulation circuit is connected to the inlet of the water pipe of the heat exchanger 82, and a pipe 94 is connected to the outlet.

  The hot water supply tank unit 90 described above includes a hot water supply tank 91, a pipe 93, a pipe 94, a water supply pipe and a hot water supply pipe (not shown), and the like. In this case, the water in the hot water supply tank 91 is taken out from the pipe 93, reaches the heat exchanger 82, passes through the water pipe of the heat exchanger 82, and passes through the refrigerant pipe of the heat pump device 80 to generate a high temperature from the compressor 1. Heat is exchanged with a high-pressure refrigerant. Thereafter, the water (warm water) exiting the heat exchanger 82 returns to the hot water supply tank 91 from the pipe 94 and is stored in the hot water supply tank 91.

  The hot water stored in the hot water supply tank 91 is taken out from a hot water supply pipe (not shown) connected to a faucet or the like of the bathroom, and used for hot water supply of a bath, a shower, and the like.

  With the above configuration, first, a normal hot water supply operation will be described. In this case, the electromagnetic valve 84 of the heat pump device 80 is opened and the electromagnetic valve 86 is closed by a control means (not shown) of the hot water supply device 70. When the compressor 81 is started, the refrigerant compressed by the compressor 81 and having a high temperature and high pressure flows into the heat exchanger 82.

  At this time, the refrigerant temperature rises to approximately + 100 ° C., and the high-temperature and high-pressure refrigerant gas heats water in the water pipe provided in the heat exchange relationship in the heat exchanger 82. The water (hot water) heated by the refrigerant leaves the heat exchanger 82 and then returns to the hot water supply tank 91 through the pipe 94. Thereby, the water in the hot water supply tank 91 is heated by the heat exchanger 81, the temperature gradually rises, and finally a predetermined high temperature hot water (for example, + 90 ° C. hot water (hot water)) is generated. As described above, the hot water in the hot water supply tank 91 is taken out from the hot water supply pipe and used for a bath or a shower. When the hot water in the hot water supply tank 91 is less than a predetermined amount, tap water is supplied from a water supply pipe (not shown), and the above-described hot water generation cycle is repeated.

  On the other hand, the refrigerant itself is cooled in the heat exchanger 82, flows out of the heat exchanger 82, and is decompressed by the expansion valve 83. At this time, since the electromagnetic valve 84 is opened and the electromagnetic valve 86 is closed as described above, all the refrigerant that has flowed out of the expansion valve 83 reaches the evaporator 85 via the electromagnetic valve 84, and absorbs heat from the outside air there. Evaporates. Thereafter, the refrigerant is repeatedly cycled to be sucked into the compressor 81.

  Next, the brine cooling operation in the present embodiment will be described. The brine cooling operation of the present embodiment is performed at night when the outside air temperature is the lowest and when the compressor 1 is not performing the cooling operation. In this case, a predetermined signal is transmitted from the controller C of the refrigeration cycle apparatus S to the control means of the hot water supply apparatus 70. Thus, the control means that has received the signal closes the electromagnetic valve 84 of the heat pump device 80 and opens the electromagnetic valve 86 so that the refrigerant decompressed by the expansion valve 83 flows into the heat exchanger 92. As a result, the refrigerant decompressed by the expansion valve 83 does not flow to the evaporator 85, but all reaches the heat exchanger 92 via the electromagnetic valve 86. Therefore, the heat exchanger 92 evaporates by taking heat from the brine in the brine tank 24 flowing through the brine circulation circuit 20. The refrigerant evaporated in the heat exchanger 92 repeats the cycle of being sucked into the compressor 1. Thereafter, the brine that has exited the heat exchanger 22 returns to the upper part of the brine tank 24 and is repeatedly discharged from the lower part to the pipe 50.

  Thus, by configuring the cooling means with the heat exchanger 92 described above, the heat pump device 80 of the hot water supply device 70 generates the brine from the brine tank 24 flowing through the brine circulation circuit 20 in the heat exchanger 92. It is possible to cool using the endothermic action. In particular, in this embodiment, the brine can be cooled by using the cold heat that has been discarded to the outside by the evaporator 85 in the heat pump operation of the heat pump device 80. Thereby, the effective use of energy can be achieved.

  In the first embodiment, as shown in FIG. 1, water supply means is provided in the lower part of the brine tank 24, and when the inside of the brine tank 24 is not full, tap water is directly supplied to the lower part in the brine tank 24. However, when the brine is water in this way, water is fed into the brine circulation circuit 20 leading to the refrigerant-to-brine heat exchanger 30, and the low-temperature tap water from the water absorption source is directly supplied to the refrigerant-to-brine. It does not matter even if it flows to the heat exchanger 30. FIG. 9 is an overall configuration diagram of the refrigeration cycle apparatus S showing an example of this case. In FIG. 9, the same reference numerals as those in FIGS. 1 to 8 have the same or similar effects or actions, and the description thereof is omitted here.

  As shown in FIG. 9, the water supply means of the present embodiment is configured by a water supply pipe 95 connected to a middle portion of the pipe 56 of the water supply pipe 95 brine circulation circuit 20 and a water supply valve 95V. One end of the water supply pipe 95 is connected to a water supply source, and the other end is connected to a middle part of the pipe 56. And it is comprised so that the tap water from a water supply source can be supplied in the brine circulation circuit 20 from the piping 56 by opening operation of the water supply valve 95V. In this case, when the valve device 95 </ b> V of the water supply pipe 95 is opened, tap water is supplied from a water supply source connected to one end of the pipe 95. The tap water flows into the pipe 56 via the pipe 95, flows from there to the refrigerant-to-brine heat exchanger 30, exchanges heat with the refrigerant flowing through the heat exchanger 30, and is heated.

  The brine heated by the refrigerant in the refrigerant-to-brine heat exchanger 30 then repeats the cycle of returning from the pipe 52 to the upper part of the brine tank 24 via the pipe 50 and the heat exchanger 22. At this time, the water returning to the upper part of the brine tank 24 is the hot water after being heated by exchanging heat with the refrigerant in the refrigerant-to-brine heat exchanger 30, so the temperature boundary layer of the brine in the brine tank 24 Therefore, water can be supplied to the brine circulation circuit 20 even during the operation of the compressor 1, that is, during the cooling operation. In particular, since the low-temperature water from the water supply means can flow directly to the refrigerant-to-brine heat exchanger 30, the refrigerant flowing through the refrigerant-to-brine heat exchanger 30 can be cooled more effectively.

  As described above in detail, according to the present invention, the refrigeration capacity of the evaporator of the refrigeration cycle apparatus S can be improved and the performance can be improved. In particular, the present invention can eliminate the inconvenience that the refrigerating capacity is extremely deteriorated in a situation where the outside air temperature is high, which contributes to the practical use of an air conditioner or a refrigerator using the refrigeration cycle apparatus S using a carbon dioxide refrigerant. be able to.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram of the refrigerating-cycle apparatus of one Example of this invention (Example 1). It is a flowchart which shows the control action of the refrigerating-cycle apparatus of FIG. It is a ph diagram of the refrigerant which flows through the refrigerant circuit of the refrigerating cycle device of Drawing 1. It is a figure which shows the relationship between the temperature of the refrigerant | coolant which flows through the refrigerant circuit of the refrigerating-cycle apparatus of FIG. 1, and entropy. It is the figure which showed the highest temperature and the lowest temperature for one month of midsummer (August) in a certain city. It is a figure explaining the cooling operation of the brine of the refrigeration cycle apparatus of FIG. It is a figure explaining the cooling operation of the brine of the refrigerating-cycle apparatus of the other Example of this invention (Example 2). It is a figure explaining the cooling operation of the brine of the refrigerating-cycle apparatus of another another Example of this invention (Example 3). It is a whole block diagram of the refrigerating-cycle apparatus of another another Example of this invention (Example 4). It is a whole block diagram of the conventional refrigeration cycle apparatus. It is a figure which shows the COP change accompanying the external temperature in the refrigeration cycle apparatus of FIG.

Explanation of symbols

C controller S refrigeration cycle apparatus 1 compressor 2 radiator 4 expansion valve 5 evaporator 7 four-way valve 10 refrigerant circuit 20 brine circulation circuit 22 heat exchanger (cooling means of the present invention)
22F Fan 24 Brine tank 26 Pump 30 Refrigerant-to-brine heat exchanger 40 Refrigerant introduction pipe 41 Refrigerant discharge pipe 42, 43, 44, 45, 46 Refrigerant piping 50, 52, 54, 56 Piping (piping for brine circulation circuit)
57 Water supply pipe 57V Water supply valve 58 Extraction pipe 60 Heat exchange pipe 62 Heat exchange part 70 Water heater 80 Heat pump device 90 Heat exchanger 95 Water supply pipe 95V Water supply valve

Claims (6)

In a refrigeration cycle apparatus having a compressor, a radiator and an evaporator, and having a refrigerant circuit using carbon dioxide as a refrigerant,
A brine tank for storing brine;
A refrigerant-to-brine heat exchanger provided on the refrigerant outlet side of the radiator, for exchanging heat between the refrigerant discharged from the radiator and the brine in the brine tank;
A brine circulation circuit for supplying the brine in the lower part of the brine tank to the refrigerant-brine heat exchanger and then returning the brine to the upper part in the brine tank;
A pump for circulating brine between the brine tank and a refrigerant to brine heat exchanger by the brine circulation circuit;
Cooling means for cooling the brine in the brine tank;
A controller for controlling the operation of the compressor and the pump,
The controller controls the operation of the compressor and the pump, and forms a brine temperature boundary layer above and below the brine tank.   The controller sets a target temperature of the refrigerant and brine that can form a temperature boundary layer of brine in the upper and lower sides of the brine tank based on an index based on the outside air temperature, and operates the compressor and the pump based on the target temperature The refrigeration cycle apparatus according to claim 1, wherein the refrigeration cycle apparatus is controlled. The brine is water, and includes a water supply means capable of supplying water to the lower part of the brine tank, and a hot water extraction unit capable of extracting hot water from the upper part of the brine tank,
When the temperature boundary layer of the brine in the brine tank is lowered, the controller supplies water to the lower part of the brine tank by the water supply means, and takes out hot water from the upper part of the brine tank from the hot water outlet. The refrigeration cycle apparatus according to claim 1 or 2.   The refrigeration cycle apparatus according to claim 1 or 2, further comprising water supply means for supplying water into the brine circulation circuit leading to the refrigerant-brine heat exchanger.   The refrigeration cycle apparatus according to any one of claims 1 to 4, wherein the cooling means cools the brine in the brine tank by air cooling or water cooling.   The refrigeration cycle apparatus according to any one of claims 1 to 4, wherein the cooling means cools the brine in the brine tank using an endothermic action generated by a heat pump device that constitutes a hot water supply device. .

Images