JP2014031930A - Refrigeration cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for executing a defrosting operation efficiently.SOLUTION: A refrigeration cycle device 100 includes: a controller 5; a main cooling medium circuit 11; and a bypass circuit 12. A first switching mechanism 41 is provided at the main cooling medium circuit 11. The first switching mechanism 41 is configured in such a manner that it selectively indicates either one of the modes out of a first mode in which a compressed cooling medium flows into a first heat exchanger 23 and a second mode in which the compressed cooling medium flows into a second heat exchanger 25. A second expansion mechanism 32 is arranged in the bypass circuit 12. In a defrosting operation, the controller 5 controls the first switching mechanism 41 in such a manner that the first switching mechanism 41 indicates the second mode, and also, controls the second expansion mechanism 32 in such a manner that the compressed cooling medium is allowed to flow the bypass circuit 12.

Description

  The present invention relates to a refrigeration cycle apparatus.

  FIG. 9 is a configuration diagram of the refrigeration cycle apparatus described in Patent Document 1. The refrigeration cycle apparatus 400 includes a refrigerant circuit 102 and a bypass circuit 103. The refrigerant circuit 102 is formed by connecting a compressor 121, a condenser 122, a supercooling heat exchanger 123, a main expansion valve 124, and an evaporator 125 in an annular shape. The bypass circuit 103 is branched from the refrigerant circuit 102 between the condenser 122 and the main expansion valve 124, and is connected to the refrigerant circuit on the suction side of the compressor 121 via the bypass expansion valve 131 and the supercooling heat exchanger 123. 102. The high-pressure refrigerant flows out of the condenser 122, then flows into the supercooling heat exchanger 123, and is cooled by the low-pressure refrigerant decompressed by the bypass expansion valve 131.

  The refrigerant circuit 102 is provided with a four-way valve 127 for switching between normal operation and defrosting operation. During the defrosting operation, the four-way valve 127 is switched to the state indicated by the broken line, and the refrigerant compressed by the compressor 121 flows into the evaporator 125. Patent Document 1 describes that the bypass expansion valve 131 is closed when the defrosting operation is performed.

JP 2011-158125 A

  In recent years, in response to problems such as global warming and depletion of fossil fuels, it has become increasingly important to reduce the consumption of resources and energy. As a method for further improving the efficiency of the refrigeration cycle apparatus, a technique for efficiently executing the defrosting operation can be one answer.

That is, this disclosure
A main refrigerant circuit formed by connecting a compressor, a first heat exchanger, a refrigerant heater, a first expansion mechanism, and a second heat exchanger, and these devices are connected in a ring;
One of a first mode in which the refrigerant compressed by the compressor flows into the first heat exchanger and a second mode in which the refrigerant compressed by the compressor flows into the second heat exchanger A first switching mechanism provided in the main refrigerant circuit between the compressor and the first heat exchanger;
Branching from the main refrigerant circuit at a first position between the refrigerant heater and the first expansion mechanism or at a first position between the first heat exchanger and the refrigerant heater; A bypass circuit connected to the main refrigerant circuit at a second position between the second heat exchanger and the first switching mechanism,
A second expansion mechanism disposed in the bypass circuit between the first position and the refrigerant heater;
During the defrosting operation for melting the frost accumulated in the second heat exchanger, the first switching mechanism is controlled so that the first switching mechanism shows the second mode, and the compressed refrigerant is A controller that controls the second expansion mechanism to allow flow through the bypass circuit from a second position toward the first position;
A refrigeration cycle apparatus is provided.

  According to the above refrigeration cycle apparatus, the compressed refrigerant can flow through the bypass circuit from the second position toward the first position during the defrosting operation. In the refrigerant heater, the density of the refrigerant at the outlet of the refrigerant heater can be reduced by exchanging heat between the refrigerant flowing through the main refrigerant circuit and the refrigerant flowing through the bypass circuit. Then, the refrigerant quantity (mass) existing in the flow path between the first heat exchanger and the refrigerant heater decreases, and the ratio of the refrigerant quantity (mass) in the other flow paths increases. That is, since the refrigerant circulation amount increases, the defrosting time can be shortened.

Configuration diagram of a refrigeration cycle apparatus according to an embodiment of the present invention Mollier diagram during defrosting operation Graph showing change in density of refrigerant in second connection pipe Flowchart of control executed in the refrigeration cycle apparatus shown in FIG. Configuration diagram of refrigeration cycle apparatus according to Modification 1 Configuration diagram of refrigeration cycle apparatus according to modification 2 Flowchart of control executed in refrigeration cycle apparatus of modification 2 Configuration diagram of a plurality of first heat exchangers Configuration diagram of conventional refrigeration cycle equipment

The first aspect of the present disclosure is:
A main refrigerant circuit formed by connecting a compressor, a first heat exchanger, a refrigerant heater, a first expansion mechanism, and a second heat exchanger, and these devices are connected in a ring;
One of a first mode in which the refrigerant compressed by the compressor flows into the first heat exchanger and a second mode in which the refrigerant compressed by the compressor flows into the second heat exchanger A first switching mechanism provided in the main refrigerant circuit between the compressor and the first heat exchanger,
Branching from the main refrigerant circuit at a first position between the refrigerant heater and the first expansion mechanism or at a first position between the first heat exchanger and the refrigerant heater; A bypass circuit connected to the main refrigerant circuit at a second position between the second heat exchanger and the first switching mechanism,
A second expansion mechanism disposed in the bypass circuit between the first position and the refrigerant heater;
During the defrosting operation for melting the frost accumulated in the second heat exchanger, the first switching mechanism is controlled so that the first switching mechanism shows the second mode, and the compressed refrigerant is A controller that controls the second expansion mechanism to allow flow through the bypass circuit from a second position toward the first position;
A refrigeration cycle apparatus is provided.

  In addition to the first aspect, the second aspect of the present disclosure branches from the bypass circuit between the refrigerant heater and the second position, and the refrigerant flowing through the bypass circuit bypasses the first switching mechanism. An auxiliary bypass circuit connected to the main refrigerant circuit at a third position between the suction port of the compressor and the first switching mechanism, the bypass circuit, and the auxiliary A refrigeration cycle apparatus further comprising a second switching mechanism disposed at a branch position with respect to the bypass circuit. If the auxiliary bypass circuit 13 and the second switching mechanism 42 are used, the heating operation and the defrosting operation can be switched smoothly. Further, it is possible to prevent the refrigerant from flowing into the bypass circuit 12 during the cooling operation.

  According to a third aspect of the present disclosure, in addition to the first aspect, there is provided a refrigeration cycle apparatus further including an on-off valve provided in the bypass circuit between the refrigerant heater and the second position.

  According to a fourth aspect of the present disclosure, in addition to any one of the first to third aspects, during the heating operation, the controller may change the first switching so that the first switching mechanism indicates the first mode. Provided is a refrigeration cycle apparatus that controls a mechanism and controls the second expansion mechanism so that a part of the refrigerant that has passed through the first heat exchanger is sucked into the compressor via the bypass circuit. To do. Thereby, the supercooling degree of a refrigerant | coolant is ensured appropriately and it can prevent that flash gas generate | occur | produces with a 1st expansion mechanism.

  In a fifth aspect of the present disclosure, in addition to the second aspect, during the heating operation, the controller controls the first switching mechanism so that the first switching mechanism indicates the first mode, and the first switching mechanism The second expansion mechanism and the second switch so that a part of the refrigerant that has passed through one heat exchanger is guided from the first position to the third position via the bypass circuit and the auxiliary bypass circuit. Provided is a refrigeration cycle apparatus for controlling a mechanism. Thereby, the supercooling degree of a refrigerant | coolant is ensured appropriately and it can prevent that flash gas generate | occur | produces with a 1st expansion mechanism.

  According to a sixth aspect of the present disclosure, in addition to any one of the first to fifth aspects, a temperature sensor disposed in the main refrigerant circuit between the first expansion mechanism and the second heat exchanger is further provided. And a refrigeration cycle apparatus that adjusts the flow rate of the refrigerant flowing through the first expansion mechanism and the second expansion mechanism based on a detection value of the temperature sensor during a defrosting operation.

  In addition to any one of the first to fifth aspects, the seventh aspect of the present disclosure further includes a temperature sensor arranged in the second heat exchanger, and a detection value of the temperature sensor during the defrosting operation. And a refrigeration cycle apparatus for adjusting the flow rate of the refrigerant flowing through the first expansion mechanism and the second expansion mechanism.

  The eighth aspect of the present disclosure further includes a temperature sensor arranged in the main refrigerant circuit between the first heat exchanger and the refrigerant heater in addition to any one of the first to fifth aspects. In the defrosting operation, a refrigeration cycle apparatus is provided that adjusts the flow rate of the refrigerant flowing through the first expansion mechanism and the second expansion mechanism based on the detection value of the temperature sensor.

  In addition to any one of the first to fifth aspects, the ninth aspect of the present disclosure further includes a temperature sensor arranged in the first heat exchanger, and a detection value of the temperature sensor during the defrosting operation. And a refrigeration cycle apparatus for adjusting the flow rate of the refrigerant flowing through the first expansion mechanism and the second expansion mechanism.

  The tenth aspect of the present disclosure further includes a temperature sensor disposed in the main refrigerant circuit between the refrigerant heater and the first expansion mechanism, in addition to any one of the first to fifth aspects. Provided is a refrigeration cycle apparatus that adjusts the flow rate of refrigerant flowing through the first expansion mechanism and the second expansion mechanism based on a detection value of the temperature sensor during a defrosting operation.

  In an eleventh aspect of the present disclosure, in addition to any one of the first to fifth aspects, the eleventh aspect further includes a temperature sensor that detects a temperature of the refrigerant sucked in the compressor, and the temperature sensor is detected during a defrosting operation. Provided is a refrigeration cycle apparatus that adjusts the flow rate of refrigerant flowing through the first expansion mechanism and the second expansion mechanism based on the value.

  A twelfth aspect of the present disclosure includes, in addition to any one of the first to fifth aspects, a temperature sensor that detects a temperature of refrigerant discharged from the compressor, and detects the temperature sensor during a defrosting operation. Provided is a refrigeration cycle apparatus that adjusts the flow rate of refrigerant flowing through the first expansion mechanism and the second expansion mechanism based on the value.

  A thirteenth aspect of the present disclosure includes, in addition to the second aspect, a temperature sensor disposed in the bypass circuit between the refrigerant heater and the second switching mechanism, and the temperature sensor during the defrosting operation A refrigeration cycle apparatus is provided that adjusts the flow rate of the refrigerant flowing through the first expansion mechanism and the second expansion mechanism based on the detected value.

  A fourteenth aspect of the present disclosure includes, in addition to any one of the first to fifth aspects, a supply path that supplies the first heat exchanger with a heat medium that is to exchange heat with a refrigerant in the first heat exchanger. And a temperature sensor arranged in the supply path, and adjusts the flow rate of the refrigerant flowing through the first expansion mechanism and the second expansion mechanism based on the detection value of the temperature sensor during the defrosting operation. A refrigeration cycle apparatus is provided.

  According to a fifteenth aspect of the present disclosure, in addition to any one of the first to fifth aspects, a recovery path that recovers a heat medium that has exchanged heat with a refrigerant in the first heat exchanger, and the recovery path are arranged in the recovery path There is provided a refrigeration cycle apparatus further comprising a temperature sensor, wherein the flow rate of the refrigerant flowing through the first expansion mechanism and the second expansion mechanism is adjusted based on a detection value of the temperature sensor during a defrosting operation.

  According to the sixth to fifteenth aspects, the density of the refrigerant can be optimized between the first heat exchanger and the refrigerant heater. It can also prevent that the flow volume of the refrigerant | coolant for melting the frost of a 2nd heat exchanger reduces too much. Moreover, when the refrigeration cycle apparatus is applied to the hot water apparatus, it is possible to prevent the piping for circulating the hot water from being frozen and broken during the defrosting operation.

  A sixteenth aspect of the present disclosure provides a cold / hot water apparatus having any one of the refrigeration cycle apparatuses according to the first to fifteenth aspects. Indoor heating can be performed using hot water, and indoor cooling can be performed using cold water.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited by the following embodiment.

  As shown in FIG. 1, the refrigeration cycle apparatus 100 includes a controller 5, a main refrigerant circuit 11, and a bypass circuit 12. The refrigeration cycle apparatus 100 is applied to a cold / hot water apparatus that can generate hot water and cold water, for example. Indoor heating can be performed using hot water, and indoor cooling can be performed using cold water.

  The main refrigerant circuit 11 includes a compressor 22, a first heat exchanger 23, a refrigerant heater 24, a first expansion mechanism 31, a second heat exchanger 25, and an accumulator 21. These devices are connected in a ring shape with a refrigerant pipe, thereby forming a main refrigerant circuit 11.

  The main refrigerant circuit 11 is provided with a first switching mechanism 41 between the compressor 22 and the first heat exchanger 23. By controlling the first switching mechanism 41, the operation mode can be switched between the heating operation and the defrosting operation (or the cooling operation). In FIG. 1, during the heating operation, the refrigerant circulates in the direction indicated by the broken-line arrow. During the defrosting operation and the cooling operation, the refrigerant circulates in the direction indicated by the solid line arrow. During the heating operation, the first heat exchanger 23 and the second heat exchanger 25 function as a condenser (heat radiator) and an evaporator, respectively. During the defrosting operation and the cooling operation, the first heat exchanger 23 and the second heat exchanger 25 function as an evaporator and a condenser (heat radiator), respectively.

  The first switching mechanism 41 is configured to selectively indicate one of the first mode and the second mode. The first mode is a mode in which the refrigerant compressed by the compressor 22 flows into the first heat exchanger 23 and corresponds to the heating operation. In the first mode, the first switching mechanism 41 connects the discharge path of the compressor 22 to the first heat exchanger 23 and connects the suction path of the compressor 22 to the second heat exchanger 25. The second mode is a mode in which the refrigerant compressed by the compressor 22 flows into the second heat exchanger 25 and corresponds to a cooling operation or a defrosting operation. In the second mode, the first switching mechanism 41 connects the discharge path of the compressor 22 to the second heat exchanger 25 and connects the suction path of the compressor 22 to the first heat exchanger 23. In the present embodiment, the first switching mechanism 41 is a four-way valve. However, the first switching mechanism 41 is not limited to a four-way valve as long as it has a function of changing the flow direction of the refrigerant. For example, the same function as a four-way valve can be realized by using two three-way valves.

  The bypass circuit 12 branches from the main refrigerant circuit 11 at a first position (in the vicinity of the point d) between the refrigerant heater 24 and the first expansion mechanism 31, and the second heat exchanger via the refrigerant heater 24. 25 and the first switching mechanism 41 is connected to the main refrigerant circuit 11 at a second position (point b). The bypass circuit 12 is provided with a second expansion mechanism 32 between the first position (near the point d) and the refrigerant heater 24. The bypass circuit 12 may branch from the main refrigerant circuit 11 between the first heat exchanger 23 and the refrigerant heater 24.

  The refrigerant heater 24 is disposed between the first heat exchanger 23 and the first expansion mechanism 31 in the main refrigerant circuit 11. The refrigerant heater 24 includes a primary heat exchange unit 24a and a secondary heat exchange unit 24b. The primary heat exchange unit 24a and the secondary heat exchange unit 24b are formed by a part of the main refrigerant circuit 11 and a part of the bypass circuit 12, respectively. The role of the refrigerant heater 24 is to ensure a sufficient degree of supercooling of the refrigerant during the heating operation. The refrigerant heater 24 is used to moderately reduce the refrigerant density during the defrosting operation. As the refrigerant heater 24, a liquid-refrigerant heat exchanger such as a double tube heat exchanger can be used.

  The first heat exchanger 23 causes heat exchange between the refrigerant and the heat medium. When the refrigeration cycle apparatus 100 is applied to a cold / hot water apparatus, the heat medium is a liquid such as water, brine, or oil. As the first heat exchanger 23, a liquid-refrigerant heat exchanger such as a double tube heat exchanger can be used. The second heat exchanger 25 causes heat exchange between the refrigerant and the outside air. As the second heat exchanger 25, an air-refrigerant heat exchanger such as a fin tube heat exchanger can be used. Note that when the refrigeration cycle apparatus 100 is applied to an air conditioner, both the heat exchangers 23 and 25 may be air-refrigerant heat exchangers.

  As shown in FIG. 8, a plurality of first heat exchangers 23 may be provided in parallel with the main refrigerant circuit 11. This configuration is advantageous when the capacity of the refrigeration cycle apparatus 100 is large and heating or cooling is individually required at a plurality of locations. Similarly, a plurality of second heat exchangers 25 may be provided in parallel with the main refrigerant circuit 11.

  A water supply path 72 and a water recovery path 71 are connected to the first heat exchanger 23. The water supply path 72 is used to supply the first heat exchanger 23 with a heat medium (typically, water) that is to exchange heat with the refrigerant in the first heat exchanger 23. The water recovery path 71 is used for recovering the heat medium exchanged with the refrigerant in the first heat exchanger 23. The water supply path 72 and the water recovery path 71 form a heat medium circuit together with devices such as a circulation pump (not shown), a heat exchange terminal (not shown) such as a radiator, and a hot water storage tank (not shown). . During the heating operation, hot water is generated by the first heat exchanger 23. During the cooling operation, cold water is generated by the first heat exchanger 23. Hot water or cold water is sent directly or via a hot water storage tank to a heat exchange terminal, and a heating function or a cooling function is exhibited by the heat exchange terminal.

  The first heat exchanger 23 can be built in the indoor unit 7 and placed indoors. Thereby, damage to the 1st heat exchanger 23 by freezing can be prevented. The second heat exchanger 25 can be arranged outdoors in order to cause heat exchange between the refrigerant and the air. In order to arrange the first heat exchanger 23 indoors and the second heat exchanger 25 outdoors, the first heat exchanger 23 (indoor unit 7) is connected to the first switching mechanism 41 by a first connection pipe 61. And is connected to the refrigerant heater 24 by a second connection pipe 62. Although depending on the installation location of the indoor unit 7 and the capacity of the refrigeration cycle apparatus 100, the lengths of the connection pipes 61 and 62 are, for example, in the range of 3 to 30 m. Connectors are arranged before and after the first connection pipe 61. Similarly, connectors are arranged before and after the second connection pipe 62. As will be described later, the connection pipes 61 and 62 are one of the causes for reducing the efficiency of the defrosting operation.

  In this embodiment, each of the expansion mechanisms 31 and 32 is a valve whose opening degree can be changed. The expansion mechanisms 31 and 32 are typically electric expansion valves and are controlled by the controller 5. By changing the opening degree of the expansion mechanisms 31 and 32, the flow rate of the refrigerant flowing through the expansion mechanisms 31 and 32 can be adjusted.

  The refrigeration cycle apparatus 100 further includes an auxiliary bypass circuit 13 and a second switching mechanism 42. The auxiliary bypass circuit 13 branches from the bypass circuit 12 between the refrigerant heater 24 and the second position (point b), and the refrigerant that has flowed through the bypass circuit 12 bypasses the first switching mechanism 41 to the compressor 22. It is connected to the main refrigerant circuit 11 at a third position (near the point f) between the suction port of the compressor 22 and the first switching mechanism 41 so as to be sucked. In the present embodiment, the third position is set in the vicinity of the inlet of the accumulator 21. The auxiliary bypass circuit 13 may be directly connected to the accumulator 21. The second switching mechanism 42 is disposed at a branch position between the bypass circuit 12 and the auxiliary bypass circuit 13. The second switching mechanism 42 is typically a three-way valve. If the auxiliary bypass circuit 13 and the second switching mechanism 42 are used, the heating operation and the defrosting operation can be switched smoothly. Further, it is possible to prevent the refrigerant from flowing into the bypass circuit 12 during the cooling operation.

  In the present embodiment, the second switching mechanism 42 is also configured to selectively show one of the first mode and the second mode. The first mode is a mode in which the refrigerant is allowed to flow through the bypass circuit 12 and the auxiliary bypass circuit 13 from the first position (near the point d) toward the third position (near the point f). It corresponds. In the first mode, the second switching mechanism 42 connects the auxiliary bypass circuit 13 to the bypass circuit 12 and allows the refrigerant to flow through the auxiliary bypass circuit 13. The second mode is a mode that allows the refrigerant to flow through the bypass circuit 12 from the second position (point b) toward the first position (near the point d), and corresponds to the defrosting operation. In other words, in the present embodiment, the first switching mechanism 41 and the second switching mechanism 42 can be controlled to interlock with each other.

  The refrigeration cycle apparatus 100 further includes an incoming water temperature sensor 51, a first temperature sensor 52, a discharge temperature sensor 53, a second temperature sensor 54, a bypass temperature sensor 55, and a discharge pressure sensor 56.

  The incoming water temperature sensor 51 is disposed in the water supply path 72 and detects the temperature of the heat medium (for example, water) to be supplied to the first heat exchanger 23.

  The first temperature sensor 52 is disposed in the main refrigerant circuit 11 between the first expansion mechanism 31 and the second heat exchanger 25. The first temperature sensor 52 may be disposed in the second heat exchanger 25. During the heating operation, the first temperature sensor 52 detects the evaporation temperature of the refrigerant. During the defrosting operation, the first temperature sensor 52 detects the temperature of the refrigerant cooled by the second heat exchanger 25. For example, when the detection value of the first temperature sensor 52 exceeds the threshold value during the defrosting operation, it is determined that the frost accumulated in the second heat exchanger 25 has sufficiently melted, and the defrosting operation is terminated. .

  The discharge temperature sensor 53 is disposed in the main refrigerant circuit 11 between the compressor 22 and the first switching mechanism 41 and detects the temperature of the refrigerant compressed by the compressor 22 (so-called discharge temperature). The discharge temperature sensor 53 may be disposed at the discharge port of the compressor 22. As known to those skilled in the art, the temperature (evaporation temperature) on the low pressure side of the refrigeration cycle can be estimated from the discharge temperature.

  The second temperature sensor 54 is disposed in the main refrigerant circuit 11 between the first heat exchanger 23 and the refrigerant heater 24. Specifically, the second temperature sensor 54 is disposed in the main refrigerant circuit 11 between the second connection pipe 62 and the refrigerant heater 24.

  The bypass temperature sensor 55 is disposed in the bypass circuit 12 between the refrigerant heater 24 and the second switching mechanism 42. The bypass temperature sensor 55 detects the temperature of the refrigerant flowing through the bypass circuit 12. During the defrosting operation, the detected value of the bypass temperature sensor 55 is approximately equal to the discharge temperature of the compressor 22.

  The discharge pressure sensor 56 is disposed in the main refrigerant circuit 11 between the compressor 22 and the first switching mechanism 41, and detects the pressure of the refrigerant compressed by the compressor 22. The discharge pressure sensor 56 may be disposed at the discharge port of the compressor 22.

  The controller 5 includes a first expansion mechanism 31, a second expansion mechanism 32, a first switching mechanism 41, and a second switching mechanism so that a heating operation, a cooling operation, and a defrosting operation are performed based on detection results of various sensors. 42 and the compressor 22 are appropriately controlled. As the controller 5, a DSP (Digital Signal Processor) including an A / D conversion circuit, an input / output circuit, an arithmetic circuit, a storage device, and the like can be used. The controller 5 stores a program for controlling the refrigeration cycle apparatus 100.

  Next, heating operation, cooling operation, and defrosting operation of the refrigeration cycle apparatus 100 will be described.

(Heating operation)
During the heating operation, the controller 5 controls the first switching mechanism 41 so that the first switching mechanism 41 indicates the first mode. Furthermore, the controller 5 controls the second expansion mechanism 32 so that a part of the refrigerant that has passed through the first heat exchanger 23 is sucked into the compressor 22 via the bypass circuit 12. In the present embodiment, a part of the refrigerant that has passed through the first heat exchanger 23 passes from the first position (in the vicinity of the point d) to the third position (the point f) via the bypass circuit 12 and the auxiliary bypass circuit 13. The second expansion mechanism 32 and the second switching mechanism 42 are controlled so as to be guided. Thereby, the degree of supercooling of the refrigerant is appropriately ensured, and the generation of flash gas in the first expansion mechanism 31 can be prevented.

  Specifically, the first switching mechanism 41 and the second switching mechanism 42 are each controlled so as to indicate the first mode (the state of the broken line in FIG. 1). After the refrigerant is discharged from the compressor 22, the refrigerant is guided to the first heat exchanger 23 via the first switching mechanism 41 and the first connection pipe 61. In the first heat exchanger 23, heat exchange occurs between the refrigerant and the heat medium (water). The cooled refrigerant is guided to the primary heat exchange unit 24 a of the refrigerant heater 24 via the second connection pipe 62. Heat exchange occurs between the refrigerant flowing through the primary heat exchange unit 24a and the refrigerant flowing through the secondary heat exchange unit 24b, and the degree of supercooling of the refrigerant flowing through the primary heat exchange unit 24a increases. The supercooled refrigerant exits from the primary heat exchange unit 24 a of the refrigerant heater 24 and is then led to a branch (first position) between the main refrigerant circuit 11 and the bypass circuit 12.

  A part of the refrigerant proceeds to the main refrigerant circuit 11, is decompressed by the first expansion mechanism 31, and is guided to the second heat exchanger 25. In the second heat exchanger 25, heat exchange occurs between the refrigerant and the air. The heated refrigerant is sucked into the compressor 22 via the first switching mechanism 41 and the accumulator 21. The remaining portion of the refrigerant proceeds to the bypass circuit 12, is decompressed by the second expansion mechanism 32, and is guided to the secondary heat exchange unit 24 b of the refrigerant heater 24. In the refrigerant heater 24, heat exchange occurs between the refrigerant flowing through the primary heat exchange unit 24a and the refrigerant flowing through the secondary heat exchange unit 24b. After passing through the bypass circuit 12, the second switching mechanism 42, and the auxiliary bypass circuit 13, the refrigerant is sucked into the compressor 22 via the accumulator 21.

  During the heating operation, the flow rate of the refrigerant flowing through the first expansion mechanism 31 and the second expansion mechanism 32 can be adjusted based on the detection value of the bypass temperature sensor 55.

(Cooling operation)
During the cooling operation, the control unit 5 controls the first switching mechanism 41 so that the first switching mechanism 41 indicates the second mode. Furthermore, the control unit 5 prohibits the compressed refrigerant from flowing from the second position (point b) toward the first position (near the point d), and the refrigerant that has passed through the second heat exchanger 25 The second expansion mechanism 32 and the second switching mechanism 42 are controlled so as to be sucked into the compressor 22 via the first expansion mechanism 31, the refrigerant heater 24 and the first heat exchanger 23.

  Specifically, the first switching mechanism 41 is controlled so as to indicate the second mode (state indicated by a solid line in FIG. 1). The second switching mechanism 42 is controlled so as to indicate the first mode (the state of the broken line in FIG. 1). The refrigerant is discharged from the compressor 22 and then guided to the second heat exchanger 25. In the second heat exchanger 25, heat exchange occurs between the refrigerant and the air. The cooled refrigerant is depressurized by the first expansion mechanism 31 and guided to a branch portion (first position) between the main refrigerant circuit 11 and the bypass circuit 12. The second expansion mechanism 32 is closed so that the refrigerant does not flow into the bypass circuit 12.

  During the cooling operation, the entire amount of the refrigerant is led to the primary heat exchange unit 24 a of the refrigerant heater 24. Since the flow rate of the refrigerant in the bypass circuit 12 is zero, heat exchange between the refrigerants does not occur in the refrigerant heat heater 24. Thereafter, the refrigerant is guided to the first heat exchanger 23 via the second connection pipe 62. In the first heat exchanger 23, heat exchange occurs between the refrigerant and the heat medium. The heated refrigerant is sucked into the compressor 22 via the first connection pipe 61, the first switching mechanism 41 and the accumulator 21.

(Defrosting operation)
If the heating operation is continued when the outside air temperature is sufficiently low, frost accumulates on the second heat exchanger 25. In order to melt the frost accumulated in the second heat exchanger 25, the defrosting operation is performed periodically or according to the frost accumulation state. When the predetermined condition is satisfied, for example, when the surface temperature of the second heat exchanger 25 falls below the threshold temperature, the defrosting operation is started. During the defrosting operation, the controller 5 controls the first switching mechanism 41 so that the first switching mechanism 41 indicates the second mode (state indicated by a solid line in FIG. 1). Furthermore, the controller 5 allows the second expansion mechanism 32 and the compressed refrigerant to allow the compressed refrigerant to flow through the bypass circuit 12 from the second position (point b) toward the first position (near point d). The second switching mechanism 42 is controlled.

  Specifically, the first switching mechanism 41 and the second switching mechanism 42 are each controlled so as to indicate the second mode (solid line state in FIG. 1). The refrigerant is discharged from the compressor 22 and then guided to the second position (point b). Most of the refrigerant is guided to the second heat exchanger 25. In the second heat exchanger 25, heat exchange occurs between the refrigerant and frost. The frost accumulated in the second heat exchanger 25 is melted by the heat of the refrigerant. The cooled refrigerant is decompressed by the first expansion mechanism 31.

  On the other hand, a part of the refrigerant proceeds to the bypass circuit 12 and is led to the secondary heat exchange unit 24 b of the refrigerant heater 24. Heat exchange occurs between the refrigerant flowing through the primary heat exchange unit 24a and the refrigerant flowing through the secondary heat exchange unit 24b, and the refrigerant flowing through the primary heat exchange unit 24a is heated. The refrigerant discharged from the secondary heat exchange unit 24b is decompressed by the second expansion mechanism 32 and merges with the refrigerant in the main refrigerant circuit 11 at the first position (near the point d).

  The merged refrigerant is guided to the primary heat exchange unit 24 a of the refrigerant heater 24. The refrigerant flowing through the primary heat exchange unit 24a is heated by the refrigerant flowing through the secondary heat exchange unit 24b. The heated refrigerant is guided to the first heat exchanger 23 via the second connection pipe 62. The refrigerant is further heated in the first heat exchanger 23 and then sucked into the compressor 22 via the first connection pipe 61, the first switching mechanism 41 and the accumulator 21. In the first heat exchanger 23, the refrigerant is heated by the heat remaining in the water supply path 72, the water recovery path 71, and the like.

  Thus, the flow direction of the secondary heat exchange part 24b of the refrigerant heater 24 differs between the heating operation and the defrosting operation. According to the present embodiment, the high-temperature refrigerant can be passed through the refrigerant heater 24 of the bypass circuit 12 during the defrosting operation. Therefore, the refrigerant can be heated by the refrigerant heater 24 before the refrigerant flows into the second connection pipe 62, and the density thereof can be lowered.

  If no refrigerant flows through the bypass circuit 12 during the defrosting operation, the refrigerant has a relatively low dryness and a high density at the outlet (point e) of the primary heat exchange unit 24a of the refrigerant heater 24. That is, the density of the refrigerant in the second connection pipe 62 is also high. As described above, the second connection pipe 62 has a length of 3 to 30 m, for example. Therefore, when the defrosting operation is performed, a considerable amount of refrigerant is held in the second connection pipe 62, and the refrigerant amount in the other part of the main refrigerant circuit 11 is reduced. That is, the mass flow rate of the refrigerant circulating in the main refrigerant circuit 11 is reduced, the amount of heat used for melting the frost of the second heat exchanger 25 is also reduced, and a long time is required for defrosting.

  On the other hand, according to this embodiment, the density of the refrigerant at the outlet (point e) of the primary heat exchanging part 24a of the refrigerant heater 24 can be lowered by flowing a high-temperature refrigerant through the bypass circuit 12. That is, the amount of refrigerant held in the second connection pipe 62 can be reduced. Therefore, the circulation amount of the refrigerant is increased and the defrosting time can be effectively shortened.

  FIG. 2 is a Mollier diagram during the defrosting operation. The cycle indicated by the points a to f is a cycle in the present embodiment. The cycle indicated by the points a ′ to f ′ is a reference cycle in the case where the refrigerant is not passed through the bypass circuit 12 during the defrosting operation. The refrigerant states at points a to f in FIG. 2 represent the refrigerant states at points a to f in FIG. 1, respectively. The points a ′ to f ′ of the reference cycle correspond to the points a to f of the cycle of this embodiment, respectively.

  According to the present embodiment, the amount of refrigerant retained in the second connection pipe 62 can be reduced, and the amount of refrigerant in other parts of the main refrigerant circuit 11 can be increased. Thereby, the density of the refrigerant | coolant of the suction | inhalation of the compressor 21 increases, and also the density of the refrigerant | coolant of the high voltage | pressure side of a refrigerating cycle can be increased. Comparing the refrigeration cycle during the defrosting operation with this embodiment and the case where no refrigerant is passed through the bypass circuit 12, the refrigeration cycle of this embodiment is generally shifted to the high pressure side. Accordingly, the amount of heat exchange in the second heat exchanger 25 is increased, so that the defrosting time can be shortened.

FIG. 3 is a graph showing changes in refrigerant density in the second connection pipe 62. When no refrigerant flows through the bypass circuit 12 during the defrosting operation, it is assumed that the density of the refrigerant at the point e ′ is D ₁ and the enthalpy is H ₁ . When the refrigerant flows through the bypass circuit 12 during the defrosting operation and the refrigerant heater 24 heats the refrigerant, the density of the refrigerant at the point e is D ₂ (<D ₁ ) and the enthalpy is H ₂ (> H ₁ ). It becomes.

  Next, defrosting control executed by the controller 5 during the defrosting operation will be described with reference to the flowchart of FIG. “Start” and “End” in FIG. 4 mean the start and end of the defrosting operation, respectively.

  First, after the start of the defrosting operation, the frequency of the compressor 22 (the number of rotations of the motor) is reduced (step S1). Next, the opening degree of the first expansion mechanism 31 (electric expansion valve) is adjusted. Specifically, the opening of the first expansion mechanism 31 is set to the initial opening for defrosting operation (step S2). Next, the first switching mechanism 41 and the second switching mechanism 42 are controlled so that the first switching mechanism 41 and the second switching mechanism 42 indicate the second mode (the state indicated by the solid line in FIG. 1) (steps S3 and S4). ). Next, the opening degree of the second expansion mechanism 32 (electric expansion valve) is adjusted. Specifically, the opening degree of the second expansion mechanism 32 is set to the initial opening degree for the defrosting operation (step S5).

  While the opening degree of the first expansion mechanism 31 and the opening degree of the second expansion mechanism 32 are fixed, the temperature Tin at the inlet of the second heat exchanger 25 (inlet during heating operation) is detected by the first temperature sensor 52. Further, the temperature Tsc at the inlet of the refrigerant heater 24 (inlet during heating operation) is detected by the second temperature sensor 54 (step S7). In step S8, it is determined whether the temperature Tsc is higher than the set temperature Tfre. When the temperature Tsc is equal to or lower than the set temperature Tfre, the opening degree of the first expansion mechanism 31 is adjusted in the closing direction and the opening degree of the second expansion mechanism 32 is opened in order to increase the heating amount by the refrigerant heater 24. The refrigerant flow rate in the bypass circuit 12 is increased by adjusting the direction (step S9). That is, the flow rate of the refrigerant flowing through the first expansion mechanism 41 and the second expansion mechanism 42 is adjusted based on the detection value of the second temperature sensor 54. Thereby, the density of the refrigerant can be optimized between the first heat exchanger 23 and the refrigerant heater 24. It can also prevent that the flow volume of the refrigerant | coolant for melting the frost of the 2nd heat exchanger 25 reduces too much.

  In step S10, it is determined whether the temperature Tin is higher than the end temperature Tdef. When the temperature Tin is higher than the end temperature Tdef, it is determined that the frost has finished melting. Thereafter, the second expansion mechanism 32 is fully closed (step S11). The first switching mechanism 41 and the second switching mechanism 42 are controlled so that the first switching mechanism 41 and the second switching mechanism 42 indicate the first mode (the state of the broken line in FIG. 1) (steps S12 and S13). Thereby, the refrigeration cycle apparatus 100 shifts to a steady operation (step S14). In step S <b> 11, the second expansion mechanism 32 is fully closed, but in steady operation, the second expansion mechanism 32 is opened and the refrigerant flows through the bypass circuit 12. The reliability of the refrigeration cycle apparatus 100 is improved by temporarily closing the second expansion mechanism 32 and opening the second expansion mechanism 32 after a while has elapsed, such as during a transition from the defrosting operation to the steady operation. there is a possibility. Of course, in step S11, the second expansion mechanism 32 may be adjusted to the opening degree during steady operation.

  During the defrosting operation, the first expansion mechanism 31 and the second expansion mechanism 32 are controlled based on the detection values of the temperature sensors such as the discharge temperature sensor 53 and the bypass temperature sensor 55, and the first expansion mechanism 31 and the first expansion mechanism 31. The flow rate of the refrigerant flowing through the two expansion mechanism 32 may be adjusted. Specifically, the temperature (so-called suction temperature) of the refrigerant at the inlet of the compressor 22 is estimated using the detection value (discharge temperature) of the discharge temperature sensor 53 or the bypass temperature sensor 55. It is well known to those skilled in the art that the suction temperature can be estimated from the discharge temperature. Further, the temperature Tsc at the inlet of the refrigerant heater 24 (inlet during heating operation) is estimated from the suction temperature. For example, the relationship between the suction temperature and the temperature Tsc is experimentally examined in advance, and the controller 5 has the relationship examined in advance, whereby the temperature Tsc can be estimated from the suction temperature. Using the estimated temperature Tsc, the processes of steps S8 and S9 in FIG. 4 are executed. Instead of the temperature Tsc, it may be determined whether or not the estimated suction temperature is higher than the set temperature Tfre1, and the process of step S9 may be executed.

  Further, during the defrosting operation, the flow rate of the refrigerant flowing through the first expansion mechanism 31 and the second expansion mechanism 32 may be adjusted based on the detection value of the first temperature sensor 52. The first temperature sensor 52 may be disposed in the second heat exchanger 25. Specifically, the state of the defrosting operation is determined based on the temperature Tin detected by the first temperature sensor 52. First, it is determined whether or not the temperature Tin is higher than the set temperature Tde. When the temperature Tin is equal to or lower than the set temperature Tde, it is determined that it is necessary to increase the amount of heat for defrosting. In order to increase the amount of heat for defrosting, it is effective to reduce the density of the refrigerant between the first heat exchanger 23 and the refrigerant heater 24. Therefore, the opening degree of the first expansion mechanism 31 is adjusted in the closing direction, and the opening degree of the second expansion mechanism 32 is adjusted in the opening direction to increase the flow rate of the refrigerant in the bypass circuit 12. Thereby, the density of a refrigerant | coolant falls between the 1st heat exchanger 23 and the refrigerant | coolant heater 24, the flow volume of the refrigerant | coolant of the 2nd heat exchanger 25 increases, and the calorie | heat amount for defrosting also increases.

  However, if the flow rate of the refrigerant in the bypass circuit 12 is too large, the flow rate of the refrigerant in the second heat exchanger 25 may be insufficient. In order to avoid falling into such a situation, the following processing may be executed. That is, the defrosting state is grasped from the time change of the temperature Tin. Specifically, when the temperature Tin continues to decrease in a temperature range equal to or lower than the set temperature, it is determined that the flow rate of the refrigerant in the bypass circuit 12 is excessive, and the opening degree of the first expansion mechanism 31 is adjusted in the opening direction. At the same time, the flow rate of the refrigerant in the bypass circuit 12 is reduced by adjusting the opening degree of the second expansion mechanism 32 in the closing direction. By performing such control, it is possible to prevent the flow rate of the refrigerant for melting the frost of the second heat exchanger 25 from being excessively reduced.

  Further, the refrigeration cycle apparatus 100 includes temperatures such as a temperature sensor disposed in the main refrigerant circuit 11 between the refrigerant superheater 24 and the first expansion mechanism 31 and an intake temperature sensor that detects the temperature of the intake refrigerant of the compressor 22. A sensor may be provided. During the defrosting operation, the first expansion mechanism 31 and the second expansion mechanism 32 are controlled based on the detection values of these sensors, and the flow rate of the refrigerant flowing through the first expansion mechanism 31 and the second expansion mechanism 32 is adjusted. May be. Specifically, using the detected value of the temperature sensor or the suction temperature sensor arranged in the main refrigerant circuit 11 between the refrigerant superheater 24 and the first expansion mechanism 31, the inlet (heating operation) of the refrigerant heater 24 is used. Estimate the temperature Tsc at the inlet of the hour. For example, the relationship between the detected value by the temperature sensor disposed in the main refrigerant circuit 11 and the temperature Tsc is experimentally examined in advance between the refrigerant superheater 24 and the first expansion mechanism 31, and the previously examined relationship is determined by the controller 5. The temperature Tsc can be estimated from the detected value. Similarly, for example, the relationship between the suction temperature and the temperature Tsc is experimentally examined in advance, and the controller 5 has the relationship examined in advance, whereby the temperature Tsc can be easily estimated from the suction temperature. Using the estimated temperature Tsc, the processes of steps S8 and S9 in FIG. 4 are executed. Instead of the temperature Tsc, it may be determined whether the estimated temperature such as the suction temperature is higher than the set temperature Tfre2, and the process of step S9 may be executed.

  In addition, during the defrosting operation, after the opening degree of the first expansion mechanism 31 and the second expansion mechanism 32 is set to the initial opening degree in steps S2 and S5, the initial opening degree is maintained until the defrosting operation is completed. Also good. In this way, although it may be disadvantageous in terms of the efficiency of the defrosting operation, complicated control can be eliminated.

  Moreover, when the refrigeration cycle apparatus 100 is applied to a hot water apparatus, the piping of the water supply path 72 and the water recovery path 71 may be frozen and damaged during the defrosting operation. For example, when the detected value of the incoming water temperature sensor 51 falls below a threshold value (for example, 5 ° C.), the first expansion mechanism 31 and the second expansion mechanism 32 are controlled so that the refrigerant flow rate in the bypass circuit 12 increases. That is, the flow rate of the refrigerant flowing through the first expansion mechanism 31 and the second expansion mechanism 32 is adjusted based on the detection value of the incoming water temperature sensor 51. In this way, since the enthalpy of the refrigerant that should flow into the first heat exchanger 25 increases, the above-mentioned problems can be prevented. Instead of the incoming water temperature sensor 51, the above control may be executed using a temperature sensor (outlet water temperature sensor) arranged in the water recovery path 71.

  Furthermore, the refrigeration cycle apparatus 100 may include a temperature sensor disposed in the first heat exchanger 23. The temperature of the heat medium in the water supply circuit 72 and the water recovery path 71 is estimated from the detection value of the temperature sensor, and when the estimated temperature falls below a threshold (for example, 5 ° C.), the refrigerant in the bypass circuit 12 The first expansion mechanism 31 and the second expansion mechanism 32 are controlled so that the flow rate increases. That is, the flow rate of the refrigerant flowing through the first expansion mechanism 31 and the second expansion mechanism 32 is adjusted based on the detection value of the temperature sensor arranged in the first heat exchanger 23. Thereby, said malfunction can be prevented.

(Modification 1)
FIG. 5 is a configuration diagram of a refrigeration cycle apparatus according to Modification 1. In FIG. 5, the same components as those in FIG.

  In the refrigeration cycle apparatus 200 of this modification, a four-way valve is used for the second switching mechanism 43. Since the four-way valve can perform the same function as the three-way valve by closing one connection port of the four-way valve, the four-way valve can be used for the second switching mechanism 43.

(Modification 2)
FIG. 6 is a configuration diagram of a refrigeration cycle apparatus according to Modification 2. 6, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  In the refrigeration cycle apparatus 300 of the present modification, the second switching mechanism 42 and the auxiliary bypass circuit 13 in the previous embodiment are omitted. Instead, the refrigeration cycle apparatus 300 includes an opening / closing valve 44 provided in the bypass circuit 12 between the refrigerant heater 24 and the second position (point b). Furthermore, when only the heating capability is required for the first heat exchanger 23, that is, when the refrigeration cycle apparatus 300 is applied to a dedicated heating machine such as a hot water heater, the on-off valve 44 can be omitted. When both functions of cooling and heating are required, the on-off valve 44 is necessary.

  Next, defrosting control executed by the controller 5 during the defrosting operation will be described with reference to the flowchart of FIG. Note that steps ST1 to ST12 shown in FIG. 7 correspond to steps S1 to S3, S5 to S10, and S12 to S14 shown in FIG. 4, respectively. The on-off valve 44 is open throughout the heating operation and the defrosting operation. In this modification, in step ST10, the opening degree of the second expansion mechanism 32 is adjusted in the closing direction. In order to improve the reliability of the refrigeration cycle apparatus 300 in the transition period, the second expansion mechanism 32 may be temporarily fully closed as described in step S11 of FIG.

  Note that it is not necessary for the refrigerant to flow through the bypass circuit 12 during the cooling operation. Therefore, the on-off valve 44 is closed during the cooling operation. However, the second expansion mechanism 32 is not fully closed but is opened at a constant opening. Thereby, it is possible to prevent the refrigerant from being confined in the bypass circuit 12 between the second expansion mechanism 32 and the on-off valve 44.

  The volume of the refrigerant changes as the temperature changes. Therefore, if the refrigerant is confined in the bypass circuit 12, the volume of the refrigerant in the bypass circuit 12 increases as the temperature rises, which may cause problems such as breakage of the bypass circuit 12. Such a problem can be prevented by slightly opening the second expansion mechanism 32.

  The refrigeration cycle apparatus according to the present invention can be widely used in cold / hot water apparatuses, hot water heaters, hot water heaters, air conditioners, and the like.

5 controller 7 indoor unit 11 main refrigerant circuit 12 bypass circuit 21 accumulator 22 compressor 23 first heat exchanger 24 refrigerant heater 25 second heat exchanger 31 first expansion mechanism 32 second expansion mechanism 41 first switching mechanism 42 , 43 Second switching mechanism 44 On-off valve 51 Inlet temperature sensor 52 First temperature sensor 53 Discharge temperature sensor 54 Second temperature sensor 55 Bypass temperature sensor 56 Discharge pressure sensor 61 First connection pipe 62 Second connection pipe 71 Water recovery path 72 Water supply path 100 to 300 Refrigeration cycle apparatus

Claims (16)

A main refrigerant circuit formed by connecting a compressor, a first heat exchanger, a refrigerant heater, a first expansion mechanism, and a second heat exchanger, and these devices are connected in a ring;
One of a first mode in which the refrigerant compressed by the compressor flows into the first heat exchanger and a second mode in which the refrigerant compressed by the compressor flows into the second heat exchanger A first switching mechanism provided in the main refrigerant circuit between the compressor and the first heat exchanger;
Branching from the main refrigerant circuit at a first position between the refrigerant heater and the first expansion mechanism or at a first position between the first heat exchanger and the refrigerant heater; A bypass circuit connected to the main refrigerant circuit at a second position between the second heat exchanger and the first switching mechanism,
A second expansion mechanism disposed in the bypass circuit between the first position and the refrigerant heater;
During the defrosting operation for melting the frost accumulated in the second heat exchanger, the first switching mechanism is controlled so that the first switching mechanism shows the second mode, and the compressed refrigerant is A controller that controls the second expansion mechanism to allow flow through the bypass circuit from a second position toward the first position;
A refrigeration cycle apparatus comprising: The compressor branches from the bypass circuit between the refrigerant heater and the second position, and the refrigerant flowing through the bypass circuit bypasses the first switching mechanism and is sucked into the compressor. An auxiliary bypass circuit connected to the main refrigerant circuit at a third position between the suction port and the first switching mechanism;
A second switching mechanism disposed at a branch position between the bypass circuit and the auxiliary bypass circuit;
The refrigeration cycle apparatus according to claim 1, further comprising:   The refrigeration cycle apparatus according to claim 1, further comprising an on-off valve provided in the bypass circuit between the refrigerant heater and the second position.   During the heating operation, the controller controls the first switching mechanism so that the first switching mechanism indicates the first mode, and a part of the refrigerant that has passed through the first heat exchanger is bypassed. The refrigeration cycle apparatus according to any one of claims 1 to 3, wherein the second expansion mechanism is controlled so as to be sucked into the compressor via a circuit.   During the heating operation, the controller controls the first switching mechanism so that the first switching mechanism indicates the first mode, and a part of the refrigerant that has passed through the first heat exchanger is bypassed. The refrigeration cycle apparatus according to claim 2, wherein the second expansion mechanism and the second switching mechanism are controlled so as to be guided from the first position to the third position via a circuit and the auxiliary bypass circuit. . A temperature sensor disposed in the main refrigerant circuit between the first expansion mechanism and the second heat exchanger;
The refrigeration cycle according to any one of claims 1 to 5, wherein a flow rate of refrigerant flowing through the first expansion mechanism and the second expansion mechanism is adjusted based on a detection value of the temperature sensor during a defrosting operation. apparatus. A temperature sensor disposed in the second heat exchanger;
The refrigeration cycle according to any one of claims 1 to 5, wherein a flow rate of refrigerant flowing through the first expansion mechanism and the second expansion mechanism is adjusted based on a detection value of the temperature sensor during a defrosting operation. apparatus. A temperature sensor disposed in the main refrigerant circuit between the first heat exchanger and the refrigerant heater;
The refrigeration cycle according to any one of claims 1 to 5, wherein a flow rate of refrigerant flowing through the first expansion mechanism and the second expansion mechanism is adjusted based on a detection value of the temperature sensor during a defrosting operation. apparatus. A temperature sensor disposed on the first heat exchanger;
The refrigeration cycle according to any one of claims 1 to 5, wherein a flow rate of refrigerant flowing through the first expansion mechanism and the second expansion mechanism is adjusted based on a detection value of the temperature sensor during a defrosting operation. apparatus. A temperature sensor disposed in the main refrigerant circuit between the refrigerant heater and the first expansion mechanism;
The refrigeration cycle according to any one of claims 1 to 5, wherein a flow rate of refrigerant flowing through the first expansion mechanism and the second expansion mechanism is adjusted based on a detection value of the temperature sensor during a defrosting operation. apparatus. A temperature sensor for detecting the temperature of refrigerant sucked in the compressor;
The refrigeration cycle according to any one of claims 1 to 5, wherein a flow rate of refrigerant flowing through the first expansion mechanism and the second expansion mechanism is adjusted based on a detection value of the temperature sensor during a defrosting operation. apparatus. A temperature sensor for detecting the temperature of the refrigerant discharged from the compressor;
The refrigeration cycle according to any one of claims 1 to 5, wherein a flow rate of refrigerant flowing through the first expansion mechanism and the second expansion mechanism is adjusted based on a detection value of the temperature sensor during a defrosting operation. apparatus. A temperature sensor disposed in the bypass circuit between the refrigerant heater and the second switching mechanism;
The refrigeration cycle apparatus according to claim 2, wherein the flow rate of the refrigerant flowing through the first expansion mechanism and the second expansion mechanism is adjusted based on a detection value of the temperature sensor during a defrosting operation. A supply path for supplying the first heat exchanger with a heat medium to be heat exchanged with the refrigerant in the first heat exchanger;
A temperature sensor disposed in the supply path,
The refrigeration cycle according to any one of claims 1 to 5, wherein a flow rate of refrigerant flowing through the first expansion mechanism and the second expansion mechanism is adjusted based on a detection value of the temperature sensor during a defrosting operation. apparatus. A recovery path for recovering the heat medium exchanged with the refrigerant in the first heat exchanger;
A temperature sensor disposed in the recovery path;
The refrigeration cycle according to any one of claims 1 to 5, wherein a flow rate of refrigerant flowing through the first expansion mechanism and the second expansion mechanism is adjusted based on a detection value of the temperature sensor during a defrosting operation. apparatus. The cold / hot water apparatus which has a refrigeration cycle apparatus described in any one of Claims 1-15.

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