JP2022159196A - Refrigeration cycle device - Google Patents

Abstract

To provide a refrigeration cycle device capable of efficiently performing cooling and heating operations by using low-pressure and high-pressure refrigerants.SOLUTION: A refrigeration cycle device 1 performs a heating operation by carrying out a dual refrigeration cycle that includes a utilization-side refrigeration cycle using a first refrigerant with a pressure of 1 MPa or less at 30°C and a heat source-side refrigeration cycle using a second refrigerant with a pressure of 1.5 MPa or more at 30°C, and performs a cooling operation by carrying out a unit refrigeration cycle using the first refrigerant.SELECTED DRAWING: Figure 3

Description

It relates to a refrigeration cycle device.

Conventionally, refrigeration cycle apparatuses using a refrigerant with a low global warming potential (GWP) have been proposed in consideration of the global environment.

For example, in the refrigeration cycle device described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2015-197254), it is proposed that the refrigerant circuit is filled with a working fluid whose GWP is equal to or less than a predetermined value.

Among the low GWP refrigerants mentioned above are low-pressure refrigerants that are used at relatively low refrigerant pressures. Such a low-pressure refrigerant has a low heat transfer ability and cannot secure a sufficient circulation amount of the refrigerant during heating operation. tends to be low.

On the other hand, using a carbon dioxide refrigerant, which is a high-pressure refrigerant with a low GWP, as the refrigerant on the heat source side and using a low-pressure refrigerant as the refrigerant on the user side, a dual refrigeration cycle is used to ensure the capacity during heating operation. can be considered. However, even in this case, the critical pressure of the carbon dioxide refrigerant on the heat source side is exceeded during cooling operation, and the COP during cooling operation becomes low.

As described above, there is a demand for a refrigeration cycle apparatus capable of efficiently performing cooling operation and heating operation when using a high-pressure refrigerant and a low-pressure refrigerant.

A refrigeration cycle apparatus according to a first aspect performs a heating operation by performing a dual refrigeration cycle including a user-side refrigeration cycle using a first refrigerant and a heat source-side refrigeration cycle using a second refrigerant. . The first refrigerant is 1 MPa or less at 30°C. The second refrigerant is 1.5 MPa or more at 30°C. The refrigeration cycle device performs cooling operation by performing a unit refrigeration cycle using the first refrigerant.

In this refrigeration cycle device, during heating operation, a user-side refrigeration cycle using a first refrigerant that is a low-pressure refrigerant of 1 MPa or less at 30° C. and a second refrigerant that is a high-pressure refrigerant of 1.5 MPa or more at 30° C. are used. Since the dual refrigerating cycle including the refrigerating cycle on the heat source side is performed, it is easy to secure the heating capacity while improving the COP. Further, in this refrigerating cycle, since a unit refrigerating cycle using the first refrigerant, which is a low-pressure refrigerant of 1 MPa or less at 30° C., is performed during cooling operation, a dual refrigerating cycle using the second refrigerant in the refrigerating cycle on the heat source side. , it is possible to avoid a decrease in COP due to the second refrigerant exceeding the critical pressure. As a result, it is possible to efficiently perform the cooling operation and the heating operation when using the high-pressure refrigerant and the low-pressure refrigerant.

A refrigerating cycle device according to a second aspect is the refrigerating cycle device according to the first aspect, including a cascade heat exchanger. The cascade heat exchanger has a first cascade flow path and a second cascade flow path. The first cascade channel is a channel through which the first refrigerant flows during heating operation. The second cascade flow path is a flow path independent of the first cascade flow path, and is a flow path for flowing the second refrigerant during heating operation. A cascade heat exchanger allows heat exchange between the first refrigerant and the second refrigerant.

In this refrigerating cycle device, the heat exchange efficiency between the refrigerant flowing through the refrigerating cycle on the heat source side and the refrigerant flowing through the refrigerating cycle on the user side can be enhanced.

A refrigerating cycle device according to a third aspect is the refrigerating cycle device according to the second aspect, which includes a utilization heat exchanger. In the utilization heat exchanger, the first refrigerant releases heat during heating operation. During heating operation, the first refrigerant evaporates when passing through the first cascade flow path, and heat is released when the second refrigerant passes through the second cascade flow path.

Note that the first refrigerant may be condensed in the utilization heat exchanger during heating operation.

The utilization heat exchanger is preferably a heat exchanger that processes a heat load, and the refrigerant flowing through the utilization heat exchanger may exchange heat with air, or may exchange heat with a fluid such as brine or water. may be

In this refrigeration cycle device, heating operation can be efficiently performed.

A refrigeration cycle apparatus according to a fourth aspect is the refrigeration cycle apparatus according to any one of the first to third aspects, and includes a utilization heat exchanger and a first outdoor heat exchanger. In the utilization heat exchanger, the first refrigerant evaporates during cooling operation. In the first outdoor heat exchanger, the first refrigerant releases heat during cooling operation.

Note that the first refrigerant may be condensed in the first outdoor heat exchanger during cooling operation.

Although the first outdoor heat exchanger is not particularly limited, for example, the refrigerant flowing through the first outdoor heat exchanger may be heat-exchanged with the air.

In this refrigeration cycle device, it is possible to efficiently perform a cooling operation using an outdoor heat source.

A refrigeration cycle apparatus according to a fifth aspect is the refrigeration cycle apparatus according to any one of the first to fourth aspects, including a second outdoor heat exchanger. In the second outdoor heat exchanger, the second refrigerant evaporates during heating operation.

Although the second outdoor heat exchanger is not particularly limited, for example, the refrigerant flowing through the second outdoor heat exchanger may be heat-exchanged with the air.

In this refrigeration cycle apparatus, it is possible to efficiently perform a heating operation using an outdoor heat source.

A refrigeration cycle device according to a sixth aspect performs a heating operation by performing a dual refrigeration cycle including a user-side refrigeration cycle using a first refrigerant and a heat source-side refrigeration cycle using a second refrigerant. . The first refrigerant is 1 MPa or less at 30°C. The second refrigerant is 1.5 MPa or more at 30°C. The refrigeration cycle device performs cooling operation by performing a dual refrigeration cycle including a user-side refrigeration cycle using the second refrigerant and a heat source-side refrigeration cycle using the first refrigerant.

In this refrigeration cycle device, during heating operation, a user-side refrigeration cycle using a first refrigerant that is a low-pressure refrigerant of 1 MPa or less at 30° C. and a second refrigerant that is a high-pressure refrigerant of 1.5 MPa or more at 30° C. are used. Since the dual refrigerating cycle including the refrigerating cycle on the heat source side is performed, it is easy to secure the heating capacity while improving the COP. In addition, in this refrigeration cycle, during cooling operation, a user-side refrigeration cycle using a second refrigerant that is a high-pressure refrigerant of 1.5 MPa or more at 30° C. and a first refrigerant that is a low-pressure refrigerant of 1 MPa or less at 30° C. In order to perform a binary refrigeration cycle including the refrigeration cycle on the heat source side used, COP due to the second refrigerant exceeding the critical pressure when the second refrigerant is the binary refrigeration cycle used in the refrigeration cycle on the heat source side can be avoided. As a result, it is possible to efficiently perform the cooling operation and the heating operation when using the high-pressure refrigerant and the low-pressure refrigerant.

A refrigeration cycle device according to a seventh aspect is the refrigeration cycle device according to the sixth aspect, including a cascade heat exchanger. The cascade heat exchanger has a first cascade flow path and a second cascade flow path independent of the first cascade flow path. The first cascade channel is a channel for flowing the first coolant. The second cascade channel is a channel for flowing the second coolant. A cascade heat exchanger allows heat exchange between the first refrigerant and the second refrigerant.

In this refrigerating cycle device, the heat exchange efficiency between the refrigerant flowing through the refrigerating cycle on the heat source side and the refrigerant flowing through the refrigerating cycle on the user side can be enhanced.

A refrigerating cycle device according to an eighth aspect is the refrigerating cycle device according to the seventh aspect, including a utilization heat exchanger. The utilization heat exchanger has a first utilization channel and a second utilization channel independent of the first utilization channel. The first use channel is a channel for flowing the first coolant. The second use channel is a channel for flowing the second coolant.

The utilization heat exchanger is preferably a heat exchanger that processes a heat load, and the refrigerant flowing through the utilization heat exchanger may exchange heat with air, or may exchange heat with a fluid such as brine or water. may be

In this refrigeration cycle apparatus, heat load processing using the first refrigerant and heat load processing using the second refrigerant are possible in the utilization heat exchanger.

A refrigerating cycle device according to a ninth aspect is the refrigerating cycle device according to the eighth aspect, wherein during heating operation, the first refrigerant evaporates when passing through the first cascade flow path, and the second refrigerant evaporates in the second cascade flow path. and heat is released when the first coolant passes through the first use channel.

Note that the first refrigerant may be condensed while passing through the first use channel during heating operation.

In this refrigeration cycle device, heating operation can be efficiently performed.

A refrigerating cycle device according to a tenth aspect is the refrigerating cycle device according to the eighth or ninth aspect, wherein during cooling operation, the first refrigerant evaporates when passing through the first cascade flow path, and the second refrigerant evaporates. Heat is released when passing through the two cascade channels, and the second refrigerant evaporates when passing through the second utilization channel.

In this refrigeration cycle device, cooling operation can be efficiently performed.

A refrigeration cycle device according to an eleventh aspect is the refrigeration cycle device according to any one of the eighth aspect to the tenth aspect. The refrigerant evaporates as it passes through the second utilization channel.

In this refrigeration cycle apparatus, it is possible to simultaneously evaporate the first refrigerant and the second refrigerant in the utilization heat exchanger during cooling operation.

A refrigerating cycle device according to a twelfth aspect is the refrigerating cycle device according to any one of the eighth aspect to the eleventh aspect, wherein during heating operation, the first refrigerant radiates heat when passing through the first use channel, Heat is radiated when the refrigerant passes through the second utilization channel.

Note that the first refrigerant may be condensed while passing through the first use channel during heating operation.

In this refrigeration cycle apparatus, it is possible to simultaneously release the heat of the first refrigerant and the second refrigerant in the utilization heat exchanger during heating operation.

A refrigeration cycle apparatus according to a thirteenth aspect is the refrigeration cycle apparatus according to any one of the sixth to twelfth aspects, including a first outdoor heat exchanger. In the first outdoor heat exchanger, the first refrigerant releases heat during cooling operation.

Note that the first refrigerant may be condensed in the first outdoor heat exchanger during cooling operation.

Although the first outdoor heat exchanger is not particularly limited, for example, the refrigerant flowing through the first outdoor heat exchanger may be heat-exchanged with the air.

In this refrigeration cycle device, it is possible to efficiently perform a cooling operation using an outdoor heat source.

A refrigeration cycle apparatus according to a fourteenth aspect is the refrigeration cycle apparatus according to any one of the sixth to thirteenth aspects, including a second outdoor heat exchanger. In the second outdoor heat exchanger, the second refrigerant evaporates during heating operation.

Although the second outdoor heat exchanger is not particularly limited, for example, the refrigerant flowing through the second outdoor heat exchanger may be heat-exchanged with the air.

In this refrigeration cycle apparatus, it is possible to efficiently perform a heating operation using an outdoor heat source.

A refrigeration cycle device according to a fifteenth aspect is the refrigeration cycle device according to any one of the first to fourteenth aspects, wherein the first refrigerant includes at least one of R1234yf and R1234ze.

In addition, the first refrigerant may consist of only R1234yf, or may consist of only R1234ze.

This refrigeration cycle device can be operated using a refrigerant with a sufficiently low global warming potential (GWP).

A refrigeration cycle device according to a sixteenth aspect is the refrigeration cycle device according to any one of the first to fifteenth aspects, wherein the second refrigerant contains carbon dioxide.

In addition, the second refrigerant may be composed only of carbon dioxide.

This refrigeration cycle apparatus can be operated using a refrigerant having a sufficiently low ozone depletion potential (ODP) and a sufficiently low global warming potential (GWP).

1 is an overall configuration diagram of a refrigeration cycle apparatus according to a first embodiment; FIG. 1 is a functional block configuration diagram of a refrigeration cycle device according to a first embodiment; FIG. FIG. 4 is a diagram showing how a refrigerant flows during cooling operation in the first embodiment; FIG. 4 is a diagram showing how a refrigerant flows during heating operation in the first embodiment; It is a whole block diagram of the refrigerating-cycle apparatus which concerns on 2nd Embodiment. It is a functional block configuration diagram of a refrigeration cycle apparatus according to a second embodiment. FIG. 10 is a diagram showing how a refrigerant flows during cooling operation of the second embodiment; FIG. 10 is a diagram showing how a refrigerant flows during heating operation in the second embodiment; It is a whole block diagram of the refrigerating-cycle apparatus which concerns on 3rd Embodiment. It is a functional block configuration diagram of a refrigeration cycle apparatus according to a third embodiment. FIG. 11 is a diagram showing how a refrigerant flows during cooling operation in the third embodiment; FIG. 11 is a diagram showing how a refrigerant flows during heating operation in the third embodiment; It is a whole block diagram of the refrigerating-cycle apparatus which concerns on 4th Embodiment. It is a functional block block diagram of the refrigerating-cycle apparatus which concerns on 4th Embodiment. FIG. 11 is a diagram showing how a refrigerant flows during a first cooling operation in the fourth embodiment; FIG. 11 is a diagram showing how a refrigerant flows during a second cooling operation of the fourth embodiment; FIG. 11 is a diagram showing how a refrigerant flows during a third cooling operation in the fourth embodiment; FIG. 11 is a diagram showing how a refrigerant flows during a first heating operation in the fourth embodiment; FIG. 11 is a diagram showing how a refrigerant flows during a second heating operation in the fourth embodiment; FIG. 11 is a diagram showing how a refrigerant flows during a third heating operation in the fourth embodiment;

(1) 1st Embodiment In FIG. 1, the schematic block diagram of the refrigerating-cycle apparatus 1 which concerns on 1st Embodiment is shown. FIG. 2 shows a functional block configuration diagram of the refrigeration cycle device 1 according to the first embodiment.

The refrigerating cycle device 1 is a device used to process a heat load by performing vapor compression refrigerating cycle operation. The refrigeration cycle device 1 has a heat load circuit 90 , a first refrigerant circuit 10 , a second refrigerant circuit 20 , an outdoor fan 9 and a controller 7 .

The heat load processed by the refrigeration cycle device 1 is not particularly limited, and heat exchange may be performed with fluids such as air, water, and brine. Water flowing through the heat load circuit 90 is supplied to the heat load heat exchanger 91 to process the heat load in the heat load heat exchanger 91 . The heat load circuit 90 is a circuit in which water as a heat medium circulates, and includes a heat load heat exchanger 91, a pump 92, and a utilization heat exchanger 13 shared with the first refrigerant circuit 10. is doing. The pump 92 circulates water in the heat load circuit 90 by being driven and controlled by the controller 7 to be described later. In the heat load circuit 90 , water flows through the heat load flow path 13 c of the heat utilization heat exchanger 13 . The utilization heat exchanger 13 has a first utilization passage 13a through which the first refrigerant flowing through the first refrigerant circuit 10 passes, as will be described later. The water flowing through the heat load channel 13c of the heat utilization exchanger 13 is cooled during the cooling operation and warmed during the heating operation by exchanging heat with the first refrigerant flowing through the first utilization channel 13a.

The first refrigerant circuit 10 includes a first compressor 11, a first switching mechanism 12, a utilization heat exchanger 13 shared with the heat load circuit 90, a first utilization expansion valve 15, and a second utilization expansion valve 16. , a heat source heat exchanger 17 shared with the second refrigerant circuit 20 , and a first outdoor heat exchanger 18 . The first refrigerant circuit 10 is filled with a first refrigerant, which is a low-pressure refrigerant, as a refrigerant. The first refrigerant is a refrigerant of 1 MPa or less at 30 ° C., for example, a refrigerant containing at least one of R1234yf and R1234ze. good.

The first compressor 11 is a positive displacement compressor driven by a compressor motor. The compressor motor is driven by being supplied with power through an inverter device. The operating capacity of the first compressor 11 can be changed by varying the drive frequency, which is the number of revolutions of the compressor motor. A discharge side of the first compressor 11 is connected to a first switching mechanism 12 . The suction side of the first compressor 11 is connected to the gas refrigerant side outlet of the first heat source flow path 17 a of the heat source heat exchanger 17 .

The first switching mechanism 12 has a switching valve 12a and a switching valve 12b. The switching valve 12 a and the switching valve 12 b are connected in parallel with each other on the discharge side of the first compressor 11 . The switching valve 12 a connects the discharge side of the first compressor 11 and the first utilization passage 13 a of the heat utilization heat exchanger 13 , and the suction side of the first compressor 11 and the first utilization flow path 13 a of the heat utilization heat exchanger 13 . It is a three-way valve that switches between a state in which it is connected to the use channel 13a and a state in which it is connected. The switching valve 12b connects the discharge side of the first compressor 11 and the first outdoor heat exchanger 18, and connects the suction side of the first compressor 11 and the first outdoor heat exchanger 18. It is a three-way valve that switches between .

A gas refrigerant side of the first use flow path 13a through which the first refrigerant flowing through the first refrigerant circuit 10 passes in the use heat exchanger 13 is connected to the switching valve 12a. Further, the liquid refrigerant side of the first use channel 13 a is connected to the first branch point A of the first refrigerant circuit 10 . The first refrigerant can cool the water flowing through the heat load circuit 90 by evaporating while flowing through the first use flow path 13 a of the heat utilization exchanger 13 , and can cool the water flowing through the first use flow path 13 a of the heat utilization heat exchanger 13 . Water flowing through thermal load circuit 90 can be warmed by condensing as it flows through path 13a.

At the first branch point A, a flow path extending from the liquid refrigerant side of the first utilization flow path 13a, a flow path extending on the side opposite to the heat source heat exchanger 17 side of the first utilization expansion valve 15, and a second utilization flow path 13a and a channel extending from the expansion valve 16 to the side opposite to the first outdoor heat exchanger 18 side are connected.

The first utilization expansion valve 15 is composed of an electronic expansion valve whose opening degree can be adjusted. The first utilization expansion valve 15 is provided in the first refrigerant circuit 10 between the first branch point A and the liquid refrigerant side inlet of the first heat source flow path 17 a of the heat source heat exchanger 17 . .

The second utilization expansion valve 16 is composed of an electronic expansion valve whose opening degree can be adjusted. The second utilization expansion valve 16 is provided in the first refrigerant circuit 10 between the first branch point A and the liquid refrigerant side outlet of the first outdoor heat exchanger 18 .

The heat source heat exchanger 17 includes a first heat source flow path 17a through which the first refrigerant flowing through the first refrigerant circuit 10 passes, and a second heat source flow path 17b through which the second refrigerant flowing through the second refrigerant circuit 20 passes. and a cascade heat exchanger for heat exchange between the first refrigerant and the second refrigerant. In the heat source heat exchanger 17, the first heat source passage 17a and the second heat source passage 17b are independent of each other, and the first refrigerant and the second refrigerant do not mix. The outlet, which is the gas refrigerant side, of the first heat source flow path 17 a of the heat source heat exchanger 17 is connected to the suction side of the first compressor 11 . The inlet, which is the liquid refrigerant side, of the first heat source flow path 17 a of the heat source heat exchanger 17 is connected to the first utilization expansion valve 15 .

The first outdoor heat exchanger 18 includes a plurality of heat transfer tubes and a plurality of fins joined to the plurality of heat transfer tubes. In this embodiment, the first outdoor heat exchanger 18 is arranged outdoors. The first refrigerant flowing through the first outdoor heat exchanger 18 exchanges heat with the air sent to the first outdoor heat exchanger 18, thereby functioning as a condenser for the first refrigerant.

The outdoor fan 9 generates an air flow with outdoor air passing through both the first outdoor heat exchanger 18 and the second outdoor heat exchanger 23 .

The second refrigerant circuit 20 has a second compressor 21, a heat source heat exchanger 17 shared with the first refrigerant circuit 10, a first heat source expansion valve 26, and a second outdoor heat exchanger 23. ing. The second refrigerant circuit 20 is filled with a second refrigerant, which is a high-pressure refrigerant, as a refrigerant. The second refrigerant is a refrigerant having a pressure of 1.5 MPa or more at 30° C., and may contain, for example, carbon dioxide, or may be composed of only carbon dioxide.

The second compressor 21 is a positive displacement compressor driven by a compressor motor. The compressor motor is driven by being supplied with power through an inverter device. The operating capacity of the second compressor 21 can be changed by varying the drive frequency, which is the number of revolutions of the compressor motor. The discharge side of the second compressor 21 is connected to the inlet, which is the gas refrigerant side, of the second heat source flow path 17 b of the heat source heat exchanger 17 . A suction side of the second compressor 21 is connected to a second outdoor heat exchanger 23 .

The inlet of the second heat source flow path 17 b of the heat source heat exchanger 17 on the gas refrigerant side is connected to the discharge side of the second compressor 21 . The outlet of the second heat source flow path 17 b of the heat source heat exchanger 17 on the liquid refrigerant side is connected to the first heat source expansion valve 26 .

The first heat source expansion valve 26 is provided in a channel between the liquid refrigerant side of the second heat source channel 17 b of the heat source heat exchanger 17 and the liquid refrigerant side of the second outdoor heat exchanger 23 .

The second outdoor heat exchanger 23 includes a plurality of heat transfer tubes and a plurality of fins joined to the plurality of heat transfer tubes. In this embodiment, the second outdoor heat exchanger 23 is arranged outdoors alongside the first outdoor heat exchanger 18 . The second refrigerant flowing through the second outdoor heat exchanger 23 exchanges heat with the air sent to the second outdoor heat exchanger 23, thereby functioning as an evaporator for the second refrigerant.

The controller 7 controls the operation of each device that constitutes the thermal load circuit 90 , the first refrigerant circuit 10 and the second refrigerant circuit 20 . Specifically, the controller 7 has a processor as a CPU provided for control, a memory, and the like.

In the refrigeration cycle apparatus 1 described above, the controller 7 controls each device to execute the refrigeration cycle, thereby performing a cooling operation for processing the cooling load in the thermal load heat exchanger 91 and a heating load in the thermal load heat exchanger 91. A heating operation is performed to process the

(1-1) Cooling operation During cooling operation, as shown in FIG. A unit refrigerating cycle is performed so as to function as a condenser for the first refrigerant, and the refrigerating cycle is not performed in the second refrigerant circuit 20 . Specifically, the switching valves 12a and 12b of the first switching mechanism 12 are switched to the connected state indicated by solid lines in FIG. is fully closed, and the degree of opening of the second utilization expansion valve 16 is controlled so that the degree of superheat of the first refrigerant sucked into the first compressor 11 satisfies a predetermined condition.

Thereby, the first refrigerant discharged from the first compressor 11 is sent to the first outdoor heat exchanger 18 via the switching valve 12 b of the first switching mechanism 12 . The first refrigerant sent to the first outdoor heat exchanger 18 is condensed by exchanging heat with the outdoor air supplied by the outdoor fan 9 . The first refrigerant that has passed through the first outdoor heat exchanger 18 is decompressed in the second utilization expansion valve 16, passes through the first branch point A, and is sent to the first utilization flow path 13a of the utilization heat exchanger 13. . The first refrigerant flowing through the first utilization channel 13a of the heat utilization exchanger 13 exchanges heat with water flowing through the heat load flow channel 13c of the heat utilization heat exchanger 13 of the heat load circuit 90, thereby evaporating. The water cooled by this heat exchange is sent to the heat load heat exchanger 91 in the heat load circuit 90 to process the cooling load. The first refrigerant evaporated in the first utilization passage 13 a of the utilization heat exchanger 13 is sucked into the first compressor 11 via the switching valve 12 a of the first switching mechanism 12 .

(1-2) Heating operation During heating operation, as shown in FIG. A refrigeration cycle is performed so as to function as an evaporator of the refrigerant, and in the second refrigerant circuit 20, the heat source heat exchanger 17 functions as a radiator for the second refrigerant, and the second outdoor heat exchanger 23 evaporates the second refrigerant. A refrigeration cycle is performed so that it functions as a container. As a result, a dual refrigeration cycle is performed by the second refrigerant circuit 20 and the first refrigerant circuit 10 during the heating operation. Specifically, the switching valves 12a and 12b of the first switching mechanism 12 are switched to the connection state indicated by the broken lines in FIG. 4, the pump 92, the first compressor 11, the second compressor 21, and the outdoor fan 9 are driven, The second utilization expansion valve 16 is fully closed, the valve opening degree of the first utilization expansion valve 15 is controlled so that the degree of superheat of the first refrigerant sucked by the first compressor 11 satisfies a predetermined condition, and the first heat source is controlled. The degree of opening of the expansion valve 26 is controlled so that the degree of superheat of the second refrigerant sucked into the second compressor 21 satisfies a predetermined condition.

As a result, the second refrigerant discharged from the second compressor 21 is sent to the heat source heat exchanger 17, and when flowing through the second heat source flow path 17b, the first refrigerant flowing through the first heat source flow path 17a and the heat Dissipate heat by exchanging. The second refrigerant that has released heat in the heat source heat exchanger 17 is decompressed in the first heat source expansion valve 26, and then heat-exchanged with the outdoor air supplied by the outdoor fan 9 in the second outdoor heat exchanger 23 to evaporate. , is sucked into the second compressor 21 . The first refrigerant discharged from the first compressor 11 is sent to the first utilization passage 13a of the utilization heat exchanger 13 via the switching valve 12a of the first switching mechanism 12 . The first refrigerant flowing through the first utilization channel 13a of the heat utilization exchanger 13 is condensed by exchanging heat with water flowing through the heat load flow channel 13c of the heat utilization heat exchanger 13 of the heat load circuit 90 . The water warmed by this heat exchange is sent to the heat load heat exchanger 91 in the heat load circuit 90 to treat the heating load. After passing through the first branch point A, the first refrigerant condensed in the first utilization flow path 13 a of the utilization heat exchanger 13 is decompressed in the first utilization expansion valve 15 . The refrigerant decompressed by the first utilization expansion valve 15 evaporates by exchanging heat with the second refrigerant flowing through the second heat source passage 17b when passing through the first heat source passage 17a of the heat source heat exchanger 17. . The first refrigerant evaporated in the first heat source flow path 17 a of the heat source heat exchanger 17 is sucked into the first compressor 11 .

(1-3) Features of First Embodiment In the refrigeration cycle apparatus 1 of the first embodiment, the first refrigerant circuit 10 uses a first refrigerant having a sufficiently low global warming potential (GWP). In addition, the second refrigerant circuit 20 uses a second refrigerant having a sufficiently low ozone depletion potential (ODP) and a sufficiently low global warming potential (GWP). Therefore, deterioration of the global environment can be suppressed.

Further, even when a first refrigerant having a sufficiently low global warming potential (GWP) is used in the first refrigerant circuit 10, the second refrigerant circuit 20 is used as the heat source side cycle for heating operation, and the first refrigerant circuit A dual refrigeration cycle is performed with 10 as the utilization side cycle. As a result, it is easier to secure the capacity during the heating operation compared to the case of performing the unitary refrigeration cycle using the first refrigerant, which is the low-pressure refrigerant.

Furthermore, although carbon dioxide is used as the second refrigerant in the second refrigerant circuit 20, the unitary refrigeration cycle by the first refrigerant circuit 10 is performed instead of the second refrigerant circuit 20 during cooling operation. As a result, the pressure of the carbon dioxide refrigerant becomes the critical pressure as in the case of performing a single refrigeration cycle using carbon dioxide refrigerant, which is a high-pressure refrigerant, or when performing a dual refrigeration cycle using carbon dioxide, which is a high-pressure refrigerant, in the heat source side cycle. The cooling operation can be performed while avoiding the COP from exceeding and becoming low. In addition, it is possible to lower the standard of pressure resistance strength required for element parts of the second refrigerant circuit 20 in which carbon dioxide, which is a high-pressure refrigerant, is used.

(2) 2nd Embodiment In FIG. 5, the schematic block diagram of the refrigerating-cycle apparatus 1a which concerns on 2nd Embodiment is shown. FIG. 6 shows a functional block configuration diagram of a refrigeration cycle device 1a according to the second embodiment.

The refrigerating cycle device 1a is a device used to process a heat load by performing vapor compression refrigerating cycle operation. The refrigerating cycle device 1 a has a heat load circuit 90 , a first refrigerant circuit 10 , a second refrigerant circuit 20 , an outdoor fan 9 and a controller 7 .

The heat load and the heat load circuit 90 processed by the refrigeration cycle device 1a are the same as in the first embodiment.

The utilization heat exchanger 13 includes a heat load flow path 13c through which water flowing through the heat load circuit 90 passes, a first utilization flow path 13a through which the first refrigerant flowing through the first refrigerant circuit 10 passes, a second refrigerant and a second utilization channel 13b through which the second refrigerant flowing through the circuit 20 passes. Water flowing through the heat load flow path 13c of the heat utilization heat exchanger 13 is cooled during cooling operation by exchanging heat with the first refrigerant flowing through the first utilization flow path 13a or the second refrigerant flowing through the second utilization flow path 13b. and warmed during heating operation.

The first refrigerant circuit 10 includes a first compressor 11, a first switching mechanism 12x, a utilization heat exchanger 13 shared by the thermal load circuit 90 and the second refrigerant circuit 20, a second utilization expansion valve 16, It has a third utilization expansion valve 14 , a heat source heat exchanger 17 shared with the second refrigerant circuit 20 , and a first outdoor heat exchanger 18 . The first refrigerant circuit 10 is filled with a first refrigerant, which is a low-pressure refrigerant, as a refrigerant. The first refrigerant is a refrigerant of 1 MPa or less at 30 ° C., for example, a refrigerant containing at least one of R1234yf and R1234ze. good.

The specific configuration of the first compressor 11 itself is the same as that of the first embodiment. The discharge side of the first compressor 11 is connected to the first switching mechanism 12x. The suction side of the first compressor 11 is connected to the gas refrigerant side outlet of the first heat source flow path 17 a of the heat source heat exchanger 17 .

The first switching mechanism 12x connects the discharge side of the first compressor 11 and the first utilization flow path 13a of the heat utilization heat exchanger 13 while connecting the suction side of the first compressor 11 and the first outdoor heat exchanger 18. and connecting the discharge side of the first compressor 11 and the first outdoor heat exchanger 18 while connecting the suction side of the first compressor 11 and the first utilization flow path 13a of the utilization heat exchanger 13. It is a four-way switching valve that switches between the state of

The gas refrigerant side of the first use flow path 13a through which the first refrigerant flowing through the first refrigerant circuit 10 passes in the use heat exchanger 13 is connected to the first switching mechanism 12x. A channel extending from the third use expansion valve 14 is connected to the liquid refrigerant side of the first use channel 13a. The first refrigerant is condensed while flowing through the first utilization channel 13 a of the heat utilization exchanger 13 , thereby warming the water flowing through the heat load circuit 90 .

The third utilization expansion valve 14 is composed of an electronic expansion valve whose opening degree can be adjusted. The third utilization expansion valve 14 is provided between the utilization heat exchanger 13 and the first branch point A in the first refrigerant circuit 10 .

At the first branch point A, a flow path extending from the third utilization expansion valve 14, a flow path extending from the liquid refrigerant side of the first heat source flow path 17a in the heat source heat exchanger 17, and a flow path extending from the second utilization expansion valve 16 to the first and a channel extending in the opposite direction to the outdoor heat exchanger 18 side are connected.

The second utilization expansion valve 16 is similar to that of the first embodiment.

The heat source heat exchanger 17 is similar to that of the first embodiment. The outlet, which is the gas refrigerant side, of the first heat source flow path 17 a of the heat source heat exchanger 17 is connected to the suction side of the first compressor 11 . The inlet, which is the liquid refrigerant side, of the first heat source flow path 17a of the heat source heat exchanger 17 is connected to the first branch point A. As shown in FIG.

The first outdoor heat exchanger 18 is similar to that of the first embodiment.

The outdoor fan 9 generates an air flow with outdoor air passing through both the first outdoor heat exchanger 18 and the second outdoor heat exchanger 23 .

The second refrigerant circuit 20 includes a second compressor 21, a utilization heat exchanger 13 shared with the heat load circuit 90 and the second refrigerant circuit 20, and a heat source heat exchanger 17 shared with the first refrigerant circuit 10. , a first heat source expansion valve 26 , a second heat source expansion valve 24 , and a second outdoor heat exchanger 23 . The second refrigerant circuit 20 is filled with a second refrigerant, which is a high-pressure refrigerant, as a refrigerant. The second refrigerant is a refrigerant having a pressure of 1.5 MPa or more at 30° C., and may contain, for example, carbon dioxide, or may be composed of only carbon dioxide.

The specific configuration of the second compressor 21 itself is the same as that of the first embodiment. The discharge side of the second compressor 21 is connected to the inlet, which is the gas refrigerant side, of the second heat source flow path 17 b of the heat source heat exchanger 17 . A suction side of the second compressor 21 is connected to a flow path extending from the third branch point C in the second refrigerant circuit 20 .

At the third branch point C, the flow path extending from the suction side of the second compressor 21, the flow path extending from the outlet on the gas refrigerant side of the second outdoor heat exchanger 23, and the second utilization heat exchanger 13 and the flow path extending from the outlet on the gas refrigerant side of the flow path 13b are connected.

The inlet of the second heat source flow path 17 b of the heat source heat exchanger 17 on the gas refrigerant side is connected to the discharge side of the second compressor 21 . An outlet on the liquid refrigerant side of the second heat source flow path 17 b of the heat source heat exchanger 17 is connected to a flow path extending from the second branch point B in the second refrigerant circuit 20 . The second refrigerant radiates heat when flowing through the second heat source passage 17b of the heat source heat exchanger 17, thereby evaporating the first refrigerant flowing through the first heat source passage 17a.

At the second branch point B, the flow path extending from the outlet on the liquid refrigerant side of the second heat source flow path 17b of the heat source heat exchanger 17, the flow path extending from the first heat source expansion valve 26, and the second heat source expansion valve 24 and are connected to each other.

The first heat source expansion valve 26 is provided in the flow path between the second branch point B and the liquid refrigerant side inlet of the second outdoor heat exchanger 23 .

The second outdoor heat exchanger 23 is the same as that of the first embodiment.

The second heat source expansion valve 24 is provided in the flow path between the second branch point B and the liquid refrigerant side inlet of the second utilization flow path 13 b of the heat utilization exchanger 13 .

The second use flow path 13b through which the second refrigerant flowing through the second refrigerant circuit 20 passes in the use heat exchanger 13 is provided in the flow path between the second heat source expansion valve 24 and the third branch point C. there is The second refrigerant can cool the water flowing through the heat load circuit 90 by evaporating while flowing through the second utilization channel 13 b of the heat utilization exchanger 13 .

The controller 7 controls the operation of each device that constitutes the thermal load circuit 90 , the first refrigerant circuit 10 and the second refrigerant circuit 20 . Specifically, the controller 7 has a processor as a CPU provided for control, a memory, and the like.

In the refrigeration cycle apparatus 1a described above, the controller 7 controls each device to execute the refrigeration cycle, thereby performing a cooling operation for processing the cooling load in the thermal load heat exchanger 91 and a heating load in the thermal load heat exchanger 91. A heating operation is performed to process the

(2-1) Cooling operation During cooling operation, as shown in FIG. 7, in the first refrigerant circuit 10, the first outdoor heat exchanger 18 functions as a condenser for the first refrigerant, and the heat source heat exchanger 17 While performing the refrigeration cycle so as to function as an evaporator for the first refrigerant, in the second refrigerant circuit 20, the heat source heat exchanger 17 functions as a radiator for the second refrigerant, and the utilization heat exchanger 13 functions as a radiator for the second refrigerant. A dual refrigeration cycle is performed by performing a refrigeration cycle so as to function as an evaporator. Specifically, the first switching mechanism 12x is switched to the connected state indicated by solid lines in FIG. is fully closed, and the first heat source expansion valve 26 is fully closed. The opening degree of the second heat source expansion valve 24 is controlled so that the degree of superheat of the second refrigerant sucked into the second compressor 21 satisfies a predetermined condition.

Thereby, the first refrigerant discharged from the first compressor 11 is sent to the first outdoor heat exchanger 18 via the first switching mechanism 12x. The first refrigerant sent to the first outdoor heat exchanger 18 is condensed by exchanging heat with the outdoor air supplied by the outdoor fan 9 . The first refrigerant that has passed through the first outdoor heat exchanger 18 is decompressed in the second utilization expansion valve 16, passes through the first branch point A, and is sent to the first heat source flow path 17a of the heat source heat exchanger 17. . The first refrigerant flowing through the first heat source flow path 17a of the heat source heat exchanger 17 evaporates by exchanging heat with the second refrigerant flowing through the second heat source flow path 17b of the heat source heat exchanger 17 . The first refrigerant evaporated in the first heat source flow path 17 a of the heat source heat exchanger 17 is sucked into the first compressor 11 .

The second refrigerant discharged from the second compressor 21 is sent to the second heat source flow path 17 b of the heat source heat exchanger 17 . The second refrigerant flowing through the second heat source passage 17b of the heat source heat exchanger 17 exchanges heat with the first refrigerant flowing through the first heat source passage 17a of the heat source heat exchanger 17 to radiate heat. The second refrigerant that has passed through the second heat source flow path 17 b of the heat source heat exchanger 17 passes through the second branch point B, is depressurized in the second heat source expansion valve 24 , and flows into the heat utilization heat exchanger 13 . The second refrigerant flowing through the second utilization channel 13b of the heat utilization exchanger 13 exchanges heat with water flowing through the heat load flow channel 13c of the utilization heat exchanger 13 of the heat load circuit 90, thereby evaporating. The water cooled by this heat exchange is sent to the heat load heat exchanger 91 in the heat load circuit 90 to process the cooling load. The second refrigerant that has passed through the second utilization channel 13b of the utilization heat exchanger 13 is sucked into the second compressor 21 .

(2-2) Heating operation During heating operation, as shown in FIG. A refrigeration cycle is performed so as to function as an evaporator of the refrigerant, and in the second refrigerant circuit 20, the heat source heat exchanger 17 functions as a radiator for the second refrigerant, and the second outdoor heat exchanger 23 evaporates the second refrigerant. A refrigeration cycle is performed so that it functions as a container. As a result, a dual refrigeration cycle is performed by the second refrigerant circuit 20 and the first refrigerant circuit 10 during the heating operation. Specifically, the first switching mechanism 12x is switched to the connected state indicated by the dashed line in FIG. is fully closed, the second heat source expansion valve 24 is fully closed, and the degree of opening of the third utilization expansion valve 14 is adjusted so that the degree of superheat of the first refrigerant sucked into the first compressor 11 satisfies a predetermined condition. The opening degree of the first heat source expansion valve 26 is controlled so that the degree of superheat of the second refrigerant sucked into the second compressor 21 satisfies a predetermined condition.

As a result, the second refrigerant discharged from the second compressor 21 is sent to the heat source heat exchanger 17, and when flowing through the second heat source flow path 17b, the first refrigerant flowing through the first heat source flow path 17a and the heat Dissipate heat by exchanging. The second refrigerant that has released heat in the heat source heat exchanger 17 passes through the second branch point B, is decompressed in the first heat source expansion valve 26, and is supplied in the second outdoor heat exchanger 23 by the outdoor fan 9. It evaporates by exchanging heat with outdoor air and is sucked into the second compressor 21 . The first refrigerant discharged from the first compressor 11 is sent to the first utilization channel 13a of the utilization heat exchanger 13 via the first switching mechanism 12x. The first refrigerant flowing through the first utilization channel 13a of the heat utilization exchanger 13 is condensed by exchanging heat with water flowing through the heat load flow channel 13c of the heat utilization heat exchanger 13 of the heat load circuit 90 . The water warmed by this heat exchange is sent to the heat load heat exchanger 91 in the heat load circuit 90 to treat the heating load. The first refrigerant condensed in the first utilization flow path 13 a of the heat utilization exchanger 13 is decompressed in the third utilization expansion valve 14 . After passing through the first branch point A, the first refrigerant decompressed in the third utilization expansion valve 14 passes through the second heat source flow path 17b when passing through the first heat source flow path 17a of the heat source heat exchanger 17. It evaporates by exchanging heat with the flowing second refrigerant. The first refrigerant evaporated in the first heat source flow path 17 a of the heat source heat exchanger 17 is sucked into the first compressor 11 .

(2-3) Features of Second Embodiment In the refrigerating cycle device 1a of the present embodiment, as in the refrigerating cycle device 1 of the first embodiment, deterioration of the global environment can be suppressed. It is easy to secure the capacity by performing a refrigeration cycle. In addition, the dual refrigeration cycle is also performed during the cooling operation, but instead of dissipating heat from the carbon dioxide refrigerant, which is the second refrigerant, in the second outdoor heat exchanger 23, the carbon dioxide refrigerant, which is the second refrigerant, is Instead of evaporating the refrigerant and condensing the first refrigerant, the heat source heat exchanger 17 evaporates the first refrigerant by radiating heat from the carbon dioxide refrigerant, which is the second refrigerant. Evaporation at 13 handles the cooling load. Therefore, the pressure of the carbon dioxide refrigerant exceeds the critical pressure and the COP is lowered by performing the cooling operation using the carbon dioxide refrigerant in the cycle on the heat source side of the binary refrigeration cycle. It can be carried out. In addition, it is possible to lower the standard of pressure resistance strength required for element parts of the second refrigerant circuit 20 in which carbon dioxide, which is a high-pressure refrigerant, is used.

(3) 3rd Embodiment In FIG. 9, the schematic block diagram of the refrigerating-cycle apparatus 1b which concerns on 3rd Embodiment is shown. FIG. 10 shows a functional block configuration diagram of a refrigeration cycle device 1b according to the third embodiment.

The refrigerating cycle device 1b is a device used to process a heat load by performing vapor compression refrigerating cycle operation. The refrigeration cycle device 1 b has a heat load circuit 90 , a first refrigerant circuit 10 , a second refrigerant circuit 20 , an outdoor fan 9 and a controller 7 .

The heat load and the heat load circuit 90 processed by the refrigeration cycle device 1b are the same as in the first embodiment.

The utilization heat exchanger 13 includes a heat load flow path 13c through which water flowing through the heat load circuit 90 passes, a first utilization flow path 13a through which the first refrigerant flowing through the first refrigerant circuit 10 passes, a second refrigerant and a second utilization channel 13b through which the second refrigerant flowing through the circuit 20 passes. Water flowing through the heat load flow path 13c of the heat utilization heat exchanger 13 is cooled during cooling operation by exchanging heat with the first refrigerant flowing through the first utilization flow path 13a or the second refrigerant flowing through the second utilization flow path 13b. and warmed during heating operation.

The first refrigerant circuit 10 includes a first compressor 11, a first switching mechanism 12, a utilization heat exchanger 13 shared by the thermal load circuit 90 and the second refrigerant circuit 20, a first utilization expansion valve 15, It has a second use expansion valve 16 , a third use expansion valve 14 , a heat source heat exchanger 17 shared with the second refrigerant circuit 20 , and a first outdoor heat exchanger 18 . The first refrigerant circuit 10 is filled with a first refrigerant, which is a low-pressure refrigerant, as a refrigerant. The first refrigerant is a refrigerant of 1 MPa or less at 30 ° C., for example, a refrigerant containing at least one of R1234yf and R1234ze. good.

The specific configuration of the first compressor 11 itself is the same as that of the first embodiment. A discharge side of the first compressor 11 is connected to a first switching mechanism 12 . The suction side of the first compressor 11 is connected to the gas refrigerant side outlet of the first heat source flow path 17 a of the heat source heat exchanger 17 .

The first switching mechanism 12 has a switching valve 12a and a switching valve 12b. The switching valve 12 a and the switching valve 12 b are connected in parallel with each other on the discharge side of the first compressor 11 . The switching valve 12 a connects the discharge side of the first compressor 11 and the first utilization passage 13 a of the heat utilization heat exchanger 13 , and the suction side of the first compressor 11 and the first utilization flow path 13 a of the heat utilization heat exchanger 13 . It is a three-way valve that switches between a state in which it is connected to the utilization channel 13a and a state in which it is connected. The switching valve 12b connects the discharge side of the first compressor 11 and the first outdoor heat exchanger 18, and connects the suction side of the first compressor 11 and the first outdoor heat exchanger 18. It is a three-way valve that switches between .

A gas refrigerant side of the first use flow path 13 a through which the first refrigerant flowing through the first refrigerant circuit 10 passes in the use heat exchanger 13 is connected to the switching valve 12 a of the first switching mechanism 12 . A channel extending from the third use expansion valve 14 is connected to the liquid refrigerant side of the first use channel 13a. The first refrigerant is condensed while flowing through the first utilization channel 13 a of the heat utilization exchanger 13 , thereby warming the water flowing through the heat load circuit 90 .

The third utilization expansion valve 14 is composed of an electronic expansion valve whose opening degree can be adjusted. The third utilization expansion valve 14 is provided between the utilization heat exchanger 13 and the first branch point A in the first refrigerant circuit 10 .

At the first branch point A, the flow path extending from the third utilization expansion valve 14, the flow path extending from the first utilization expansion valve 15, and the side opposite to the first outdoor heat exchanger 18 side from the second utilization expansion valve 16 is connected to the flow path extending to the

The first utilization expansion valve 15 is similar to that of the first embodiment.

The second utilization expansion valve 16 is similar to that of the first embodiment.

The heat source heat exchanger 17 is similar to that of the first embodiment. The outlet, which is the gas refrigerant side, of the first heat source flow path 17 a of the heat source heat exchanger 17 is connected to the suction side of the first compressor 11 . The inlet, which is the liquid refrigerant side, of the first heat source flow path 17 a of the heat source heat exchanger 17 is connected to the flow path extending from the first utilization expansion valve 15 .

The first outdoor heat exchanger 18 is similar to that of the first embodiment.

The outdoor fan 9 generates an air flow with outdoor air passing through both the first outdoor heat exchanger 18 and the second outdoor heat exchanger 23 .

The second refrigerant circuit 20 includes a second compressor 21, a utilization heat exchanger 13 shared with the heat load circuit 90 and the second refrigerant circuit 20, and a heat source heat exchanger 17 shared with the first refrigerant circuit 10. , a first heat source expansion valve 26 , a second heat source expansion valve 24 , and a second outdoor heat exchanger 23 . The second refrigerant circuit 20 is filled with a second refrigerant, which is a high-pressure refrigerant, as a refrigerant. The second refrigerant is a refrigerant having a pressure of 1.5 MPa or more at 30° C., and may contain, for example, carbon dioxide, or may be composed of only carbon dioxide.

The specific configuration of the second compressor 21 itself is the same as that of the first embodiment. The discharge side of the second compressor 21 is connected to the inlet, which is the gas refrigerant side, of the second heat source flow path 17 b of the heat source heat exchanger 17 . A suction side of the second compressor 21 is connected to a flow path extending from the third branch point C in the second refrigerant circuit 20 .

At the third branch point C, the flow path extending from the suction side of the second compressor 21, the flow path extending from the outlet on the gas refrigerant side of the second outdoor heat exchanger 23, and the second utilization heat exchanger 13 and the flow path extending from the outlet on the gas refrigerant side of the flow path 13b are connected.

The inlet of the second heat source flow path 17 b of the heat source heat exchanger 17 on the gas refrigerant side is connected to the discharge side of the second compressor 21 . An outlet on the liquid refrigerant side of the second heat source flow path 17 b of the heat source heat exchanger 17 is connected to a flow path extending from the second branch point B in the second refrigerant circuit 20 . The second refrigerant radiates heat when flowing through the second heat source passage 17b of the heat source heat exchanger 17, thereby evaporating the first refrigerant flowing through the first heat source passage 17a.

At the second branch point B, the flow path extending from the outlet on the liquid refrigerant side of the second heat source flow path 17b of the heat source heat exchanger 17, the flow path extending from the first heat source expansion valve 26, and the second heat source expansion valve 24 and are connected to each other.

The first heat source expansion valve 26 is provided in the flow path between the second branch point B and the liquid refrigerant side inlet of the second outdoor heat exchanger 23 .

The second outdoor heat exchanger 23 is the same as that of the first embodiment.

The second heat source expansion valve 24 is provided in the flow path between the second branch point B and the liquid refrigerant side inlet of the second utilization flow path 13 b of the heat utilization exchanger 13 .

The second use flow path 13b through which the second refrigerant flowing through the second refrigerant circuit 20 passes in the use heat exchanger 13 is provided in the flow path between the second heat source expansion valve 24 and the third branch point C. there is The second refrigerant can cool the water flowing through the heat load circuit 90 by evaporating while flowing through the second utilization channel 13 b of the heat utilization exchanger 13 .

The controller 7 controls the operation of each device that constitutes the thermal load circuit 90 , the first refrigerant circuit 10 and the second refrigerant circuit 20 . Specifically, the controller 7 has a processor as a CPU provided for control, a memory, and the like.

In the refrigeration cycle apparatus 1b described above, the controller 7 controls each device to execute the refrigeration cycle, thereby performing a cooling operation for processing the cooling load in the thermal load heat exchanger 91 and a heating load in the thermal load heat exchanger 91. A heating operation is performed to process the

(3-1) Cooling operation During cooling operation, as shown in FIG. 11, in the first refrigerant circuit 10, the first outdoor heat exchanger 18 functions as a condenser for the first refrigerant, and the heat source heat exchanger 17 While performing the refrigeration cycle so as to function as an evaporator for the first refrigerant, in the second refrigerant circuit 20, the heat source heat exchanger 17 functions as a radiator for the second refrigerant, and the utilization heat exchanger 13 functions as a radiator for the second refrigerant. A dual refrigeration cycle is performed by performing a refrigeration cycle so as to function as an evaporator. Specifically, the switching valves 12a and 12b of the first switching mechanism 12 are switched to the connected state indicated by solid lines in FIG. 11, the pump 92, the first compressor 11, the second compressor 21, and the outdoor fan 9 are driven, The third utilization expansion valve 14 is fully closed, the first heat source expansion valve 26 is fully closed, and one of the first utilization expansion valve 15 and the second utilization expansion valve 16 is fully opened while the other valve is opened. The degree of superheat of the first refrigerant sucked into the first compressor 11 satisfies a predetermined condition, and the valve opening degree of the second heat source expansion valve 24 is controlled to superheat the second refrigerant sucked into the second compressor 21. The degree is controlled so that it satisfies a predetermined condition.

Thereby, the first refrigerant discharged from the first compressor 11 is sent to the first outdoor heat exchanger 18 via the switching valve 12 b of the first switching mechanism 12 . The first refrigerant sent to the first outdoor heat exchanger 18 is condensed by exchanging heat with the outdoor air supplied by the outdoor fan 9 . The first refrigerant that has passed through the first outdoor heat exchanger 18 is decompressed in the second use expansion valve 16 and passes through the first branch point A, or after passing through the first branch point A, the first use expansion valve 15 , and sent to the first heat source flow path 17 a of the heat source heat exchanger 17 . The first refrigerant flowing through the first heat source flow path 17a of the heat source heat exchanger 17 evaporates by exchanging heat with the second refrigerant flowing through the second heat source flow path 17b of the heat source heat exchanger 17 . The first refrigerant evaporated in the first heat source flow path 17 a of the heat source heat exchanger 17 is sucked into the first compressor 11 .

The second refrigerant discharged from the second compressor 21 is sent to the second heat source flow path 17 b of the heat source heat exchanger 17 . The second refrigerant flowing through the second heat source passage 17b of the heat source heat exchanger 17 exchanges heat with the first refrigerant flowing through the first heat source passage 17a of the heat source heat exchanger 17 to radiate heat. The second refrigerant that has passed through the second heat source flow path 17 b of the heat source heat exchanger 17 passes through the second branch point B, is depressurized in the second heat source expansion valve 24 , and flows into the heat utilization heat exchanger 13 . The second refrigerant flowing through the second utilization channel 13b of the heat utilization exchanger 13 exchanges heat with water flowing through the heat load flow channel 13c of the utilization heat exchanger 13 of the heat load circuit 90, thereby evaporating. The water cooled by this heat exchange is sent to the heat load heat exchanger 91 in the heat load circuit 90 to process the cooling load. The second refrigerant that has passed through the second utilization channel 13b of the utilization heat exchanger 13 is sucked into the second compressor 21 .

(3-2) Heating operation During heating operation, as shown in FIG. A refrigeration cycle is performed so as to function as an evaporator of the refrigerant, and in the second refrigerant circuit 20, the heat source heat exchanger 17 functions as a radiator for the second refrigerant, and the second outdoor heat exchanger 23 evaporates the second refrigerant. A refrigeration cycle is performed so that it functions as a container. As a result, a dual refrigeration cycle is performed by the second refrigerant circuit 20 and the first refrigerant circuit 10 during the heating operation. Specifically, the switching valves 12a and 12b of the first switching mechanism 12 are switched to the connection state indicated by the dashed lines in FIG. 12, the pump 92, the first compressor 11, the second compressor 21, and the outdoor fan 9 are driven, The second utilization expansion valve 16 is fully closed, the second heat source expansion valve 24 is fully closed, and the valve opening degree of the third utilization expansion valve 14 or the first utilization expansion valve 15 is sucked into the first compressor 11. The degree of superheat of the first refrigerant is controlled so as to satisfy a predetermined condition, and the degree of opening of the first heat source expansion valve 26 is controlled so that the degree of superheat of the second refrigerant sucked into the second compressor 21 satisfies the predetermined condition. .

As a result, the second refrigerant discharged from the second compressor 21 is sent to the heat source heat exchanger 17, and when flowing through the second heat source flow path 17b, the first refrigerant flowing through the first heat source flow path 17a and the heat Dissipate heat by exchanging. The second refrigerant that has released heat in the heat source heat exchanger 17 passes through the second branch point B, is decompressed in the first heat source expansion valve 26, and is supplied in the second outdoor heat exchanger 23 by the outdoor fan 9. It evaporates by exchanging heat with outdoor air and is sucked into the second compressor 21 . The first refrigerant discharged from the first compressor 11 is sent to the first utilization passage 13a of the utilization heat exchanger 13 via the switching valve 12a of the first switching mechanism 12 . The first refrigerant flowing through the first utilization channel 13a of the heat utilization exchanger 13 is condensed by exchanging heat with water flowing through the heat load flow channel 13c of the heat utilization heat exchanger 13 of the heat load circuit 90 . The water warmed by this heat exchange is sent to the heat load heat exchanger 91 in the heat load circuit 90 to treat the heating load. The first refrigerant condensed in the first utilization flow path 13a of the utilization heat exchanger 13 passes through the first branch point A after being decompressed in the third utilization expansion valve 14, or after passing through the first branch point A The pressure is reduced in the first utilization expansion valve 15 . The first refrigerant that has passed through the first branch point A evaporates by exchanging heat with the second refrigerant that flows through the second heat source flow path 17b when passing through the first heat source flow path 17a of the heat source heat exchanger 17. . The first refrigerant evaporated in the first heat source flow path 17 a of the heat source heat exchanger 17 is sucked into the first compressor 11 .

(3-3) Features of the Third Embodiment The refrigerating cycle device 1b of the present embodiment can suppress the deterioration of the global environment, as with the refrigerating cycle device 1 of the first embodiment. easy to secure. In addition, the dual refrigeration cycle is also performed during the cooling operation, but instead of dissipating heat from the carbon dioxide refrigerant, which is the second refrigerant, in the second outdoor heat exchanger 23, the carbon dioxide refrigerant, which is the second refrigerant, is Instead of evaporating the refrigerant and condensing the first refrigerant, the heat source heat exchanger 17 evaporates the first refrigerant by radiating heat from the carbon dioxide refrigerant, which is the second refrigerant. Evaporation at 13 handles the cooling load. Therefore, the pressure of the carbon dioxide refrigerant exceeds the critical pressure and the COP is lowered by performing the cooling operation using the carbon dioxide refrigerant in the cycle on the heat source side of the binary refrigeration cycle. It can be carried out. In addition, it is possible to lower the standard of pressure resistance strength required for element parts of the second refrigerant circuit 20 in which carbon dioxide, which is a high-pressure refrigerant, is used.

(4) Fourth Embodiment FIG. 13 shows a schematic configuration diagram of a refrigeration cycle apparatus 1c according to a fourth embodiment. FIG. 14 shows a functional block configuration diagram of a refrigeration cycle device 1c according to the fourth embodiment.

The refrigerating cycle device 1c is a device used to process a heat load by performing a vapor compression refrigerating cycle operation. The refrigeration cycle device 1 c has a heat load circuit 90 , a first refrigerant circuit 10 , a second refrigerant circuit 20 , an outdoor fan 9 and a controller 7 .

The heat load and the heat load circuit 90 processed by the refrigeration cycle device 1c are the same as in the first embodiment.

The utilization heat exchanger 13 includes a heat load flow path 13c through which water flowing through the heat load circuit 90 passes, a first utilization flow path 13a through which the first refrigerant flowing through the first refrigerant circuit 10 passes, a second refrigerant and a second utilization channel 13b through which the second refrigerant flowing through the circuit 20 passes. The water flowing through the heat load flow path 13c of the heat utilization exchanger 13 exchanges heat with the first refrigerant flowing through the first utilization flow path 13a and/or the second refrigerant flowing through the second utilization flow path 13b. It is sometimes cooled and warmed during heating operation.

The first refrigerant circuit 10 includes a first compressor 11, a first switching mechanism 12, a utilization heat exchanger 13 shared by the thermal load circuit 90 and the second refrigerant circuit 20, a first utilization expansion valve 15, It has a second use expansion valve 16 , a third use expansion valve 14 , a heat source heat exchanger 17 shared with the second refrigerant circuit 20 , and a first outdoor heat exchanger 18 . The first refrigerant circuit 10 is filled with a first refrigerant, which is a low-pressure refrigerant, as a refrigerant. The first refrigerant is a refrigerant of 1 MPa or less at 30 ° C., for example, a refrigerant containing at least one of R1234yf and R1234ze. good.

The specific configuration of the first compressor 11 itself is the same as that of the first embodiment. The discharge side and the suction side of the first compressor 11 are connected to different connection points of the first switching mechanism 12, respectively.

The first switching mechanism 12 has a switching valve 12a, a switching valve 12b, and a switching valve 12c. The switching valve 12 a , the switching valve 12 b and the switching valve 12 c are connected in parallel with each other on the discharge side of the first compressor 11 . The switching valve 12 a connects the discharge side of the first compressor 11 and the first utilization passage 13 a of the heat utilization heat exchanger 13 , and the suction side of the first compressor 11 and the first utilization flow path 13 a of the heat utilization heat exchanger 13 . It is a three-way valve that switches between a state in which it is connected to the utilization channel 13a and a state in which it is connected. The switching valve 12b connects the discharge side of the first compressor 11 and the first outdoor heat exchanger 18, and connects the suction side of the first compressor 11 and the first outdoor heat exchanger 18. It is a three-way valve that switches between . The switching valve 12 c connects the discharge side of the first compressor 11 and the first heat source flow path 17 a of the heat source heat exchanger 17 , and the suction side of the first compressor 11 and the first heat source heat exchanger 17 . It is a three-way valve that switches between a state in which it is connected to the heat source channel 17a and a state in which it is connected.

A gas refrigerant side of the first use flow path 13 a through which the first refrigerant flowing through the first refrigerant circuit 10 passes in the use heat exchanger 13 is connected to the switching valve 12 a of the first switching mechanism 12 . A channel extending from the third use expansion valve 14 is connected to the liquid refrigerant side of the first use channel 13a. The first refrigerant can cool the water flowing through the heat load circuit 90 by evaporating while flowing through the first use flow path 13 a of the heat utilization exchanger 13 , and can cool the water flowing through the first use flow path 13 a of the heat utilization heat exchanger 13 . Water flowing through thermal load circuit 90 can be warmed by condensing as it flows through path 13a.

The third utilization expansion valve 14 is composed of an electronic expansion valve whose opening degree can be adjusted. The third utilization expansion valve 14 is provided between the utilization heat exchanger 13 and the first branch point A in the first refrigerant circuit 10 .

At the first branch point A, the flow path extending from the third utilization expansion valve 14, the flow path extending from the first utilization expansion valve 15, and the side opposite to the first outdoor heat exchanger 18 side from the second utilization expansion valve 16 is connected to the flow path extending to the

The first utilization expansion valve 15 is similar to that of the first embodiment.

The second utilization expansion valve 16 is similar to that of the first embodiment.

The heat source heat exchanger 17 is similar to that of the first embodiment. An outlet on the gas refrigerant side of the first heat source flow path 17 a of the heat source heat exchanger 17 is connected to the switching valve 12 c of the first switching mechanism 12 . The inlet, which is the liquid refrigerant side, of the first heat source flow path 17 a of the heat source heat exchanger 17 is connected to the flow path extending from the first utilization expansion valve 15 .

The first outdoor heat exchanger 18 is similar to that of the first embodiment.

The outdoor fan 9 generates an air flow with outdoor air passing through both the first outdoor heat exchanger 18 and the second outdoor heat exchanger 23 .

The second refrigerant circuit 20 is shared with the second compressor 21 , the second switching mechanism 22 , the heat load circuit 90 and the heat utilization heat exchanger 13 shared with the second refrigerant circuit 20 , and the first refrigerant circuit 10 . A heat source heat exchanger 17 , a first heat source expansion valve 26 , a second heat source expansion valve 24 , a third heat source expansion valve 25 , and a second outdoor heat exchanger 23 . The second refrigerant circuit 20 is filled with a second refrigerant, which is a high-pressure refrigerant, as a refrigerant. The second refrigerant is a refrigerant having a pressure of 1.5 MPa or more at 30° C., and may contain, for example, carbon dioxide, or may be composed of only carbon dioxide.

The specific configuration of the second compressor 21 itself is the same as that of the first embodiment. The discharge side and the suction side of the second compressor 21 are connected to different connection points of the second switching mechanism 22, respectively.

The second switching mechanism 22 has a switching valve 22a, a switching valve 22b, and a switching valve 22c. The switching valve 22 a , the switching valve 22 b and the switching valve 22 c are connected in parallel with each other on the discharge side of the second compressor 21 . The switching valve 22 a connects the discharge side of the second compressor 21 and the second utilization flow path 13 b of the heat utilization heat exchanger 13 , and the suction side of the second compressor 21 and the second utilization flow path 13 b of the heat utilization heat exchanger 13 . It is a three-way valve that switches between a state in which it is connected to the utilization channel 13b and a state in which it is connected. The switching valve 22b connects the discharge side of the second compressor 21 and the second outdoor heat exchanger 23, and connects the suction side of the second compressor 21 and the second outdoor heat exchanger 23. It is a three-way valve that switches between . The switching valve 22 c connects the discharge side of the second compressor 21 and the second heat source flow path 17 b of the heat source heat exchanger 17 , and the suction side of the second compressor 21 and the second heat source heat exchanger 17 . It is a three-way valve that switches between a state in which it is connected to the heat source channel 17b and a state in which it is connected.

The inlet on the gas refrigerant side of the second heat source flow path 17 b of the heat source heat exchanger 17 is connected to the switching valve 22 c of the second switching mechanism 22 . An outlet on the liquid refrigerant side of the second heat source flow path 17 b of the heat source heat exchanger 17 is connected to a flow path extending from the third heat source expansion valve 25 . The second refrigerant radiates heat when flowing through the second heat source passage 17b of the heat source heat exchanger 17, thereby evaporating the first refrigerant flowing through the first heat source passage 17a.

At the second branch point B, the channel extending from the third heat source expansion valve 25, the channel extending from the first heat source expansion valve 26, and the channel extending from the second heat source expansion valve 24 are connected.

The first heat source expansion valve 26 is provided in the flow path between the second branch point B and the liquid refrigerant side inlet of the second outdoor heat exchanger 23 .

The second outdoor heat exchanger 23 is the same as that of the first embodiment.

The second heat source expansion valve 24 is provided in the flow path between the second branch point B and the liquid refrigerant side inlet of the second utilization flow path 13 b of the heat utilization exchanger 13 .

The second use flow path 13b through which the second refrigerant flowing through the second refrigerant circuit 20 passes in the use heat exchanger 13 is a flow path between the second heat source expansion valve 24 and the switching valve 22a of the second switching mechanism 22. is provided in The second refrigerant can cool the water flowing through the heat load circuit 90 by evaporating while flowing through the second use flow path 13 b of the heat utilization exchanger 13 , and can cool the water flowing through the second use flow path 13 b of the heat utilization heat exchanger 13 . The water flowing through the thermal load circuit 90 can be warmed by releasing heat while flowing through the path 13b.

The controller 7 controls the operation of each device that constitutes the thermal load circuit 90 , the first refrigerant circuit 10 and the second refrigerant circuit 20 . Specifically, the controller 7 has a processor as a CPU provided for control, a memory, and the like.

In the refrigeration cycle apparatus 1c described above, the controller 7 controls each device to execute the refrigeration cycle, thereby performing a cooling operation for processing the cooling load in the thermal load heat exchanger 91 and a heating load in the thermal load heat exchanger 91. A heating operation is performed to process the

(4-1) Cooling Operation During the cooling operation, a first cooling operation, a second cooling operation, and a third cooling operation are selectively performed.

In the first cooling operation, as shown in FIG. 15, in the first refrigerant circuit 10, the first outdoor heat exchanger 18 functions as a condenser for the first refrigerant, and the utilization heat exchanger 13 functions as an evaporator for the first refrigerant. The unitary refrigerating cycle is performed by stopping the second compressor 21 in the second refrigerant circuit 20 . Specifically, the switching valves 12a, 12b, and 12c of the first switching mechanism 12 are switched to the connected state indicated by solid lines in FIG. The valve 16 is fully opened, the first utilization expansion valve 15 is fully closed, and the degree of opening of the third utilization expansion valve 14 is controlled so that the degree of superheat of the first refrigerant sucked into the first compressor 11 satisfies a predetermined condition. control to fill.

Thereby, the first refrigerant discharged from the first compressor 11 is sent to the first outdoor heat exchanger 18 via the switching valve 12 b of the first switching mechanism 12 . The first refrigerant sent to the first outdoor heat exchanger 18 is condensed by exchanging heat with the outdoor air supplied by the outdoor fan 9 . The first refrigerant that has passed through the first outdoor heat exchanger 18 passes through the second utilization expansion valve 16 and the first branch point A, is decompressed in the third utilization expansion valve 14, and then flows into the utilization heat exchanger 13. do. The first refrigerant flowing through the first utilization channel 13a of the heat utilization exchanger 13 exchanges heat with water flowing through the heat load flow channel 13c of the heat utilization heat exchanger 13 of the heat load circuit 90, thereby evaporating. The water cooled by this heat exchange is sent to the heat load heat exchanger 91 in the heat load circuit 90 to process the cooling load. The first refrigerant evaporated in the first use channel 13 a is sucked into the first compressor 11 via the switching valve 12 a of the first switching mechanism 12 .

The second cooling operation is performed when the required temperature of the heat medium flowing through the heat load circuit 90 falls below a predetermined value, increasing the cooling load and causing the unitary refrigeration cycle by the first refrigerant circuit 10 to run out of capacity. . This second cooling operation is performed when the temperature required in the heat load circuit 90 is low, particularly in a refrigeration cycle apparatus in which the heat medium flowing through the heat load circuit 90 is antifreeze. In the second cooling operation, as shown in FIG. 16, in the first refrigerant circuit 10, the first outdoor heat exchanger 18 functions as a condenser for the first refrigerant, and the heat source heat exchanger 17 functions as an evaporator for the first refrigerant. In the second refrigerant circuit 20, the heat source heat exchanger 17 is operated as a radiator for the second refrigerant, and the heat exchanger 13 is operated as an evaporator for the second refrigerant. A two-dimensional refrigeration cycle is performed by performing Specifically, the switching valves 12a, 12b, and 12c of the first switching mechanism 12 are switched to the connected state indicated by solid lines in FIG. 16, and the switching valves 22a, 22b, and 22c of the second switching mechanism 22 are indicated by solid lines in FIG. After switching to the connected state, the pump 92, the first compressor 11, the second compressor 21, and the outdoor fan 9 are driven. Then, the second use expansion valve 16 is controlled to be fully open, the third use expansion valve 14 is fully closed, and the valve opening degree of the first use expansion valve 15 is adjusted to superheat the first refrigerant sucked by the first compressor 11. The degree is controlled so that it satisfies a predetermined condition. Furthermore, the first heat source expansion valve 26 is controlled to a fully closed state, the third heat source expansion valve 25 is controlled to a fully open state, and the valve opening degree of the second heat source expansion valve 24 is set to the second Control is performed so that the degree of superheat of the refrigerant satisfies a predetermined condition.

Thereby, the first refrigerant discharged from the first compressor 11 is sent to the first outdoor heat exchanger 18 via the switching valve 12 b of the first switching mechanism 12 . The first refrigerant sent to the first outdoor heat exchanger 18 is condensed by exchanging heat with the outdoor air supplied by the outdoor fan 9 . After passing through the first outdoor heat exchanger 18 , the first refrigerant passes through the second utilization expansion valve 16 , is decompressed in the first utilization expansion valve 15 , and then flows into the heat source heat exchanger 17 . The first refrigerant flowing through the first heat source passage 17a of the heat source heat exchanger 17 exchanges heat with the second refrigerant flowing through the second heat source passage 17b and evaporates. The first refrigerant evaporated in the heat source heat exchanger 17 is sucked into the first compressor 11 via the switching valve 12 c of the first switching mechanism 12 . The second refrigerant discharged from the second compressor 21 is sent to the heat source heat exchanger 17 via the switching valve 22 c of the second switching mechanism 22 . The second refrigerant flowing through the second heat source channel 17b of the heat source heat exchanger 17 releases heat by exchanging heat with the first refrigerant flowing through the first heat source channel 17a. After passing through the heat source heat exchanger 17 , the second refrigerant passes through the third heat source expansion valve 25 , is decompressed by the second heat source expansion valve 24 , and then flows into the utilization heat exchanger 13 . The second refrigerant flowing through the second utilization channel 13b of the utilization heat exchanger 13 exchanges heat with the antifreeze flowing through the heat load flow channel 13c of the utilization heat exchanger 13 of the heat load circuit 90, thereby evaporating. The antifreeze cooled by this heat exchange is sent to the heat load heat exchanger 91 in the heat load circuit 90 to process the cooling load. The second refrigerant evaporated in the heat utilization exchanger 13 is sucked into the second compressor 21 via the switching valve 22 a of the second switching mechanism 22 .

The third cooling operation is performed when the temperature of the heat medium flowing through the heat load circuit 90 is higher than a predetermined value and the cooling load is large, and when the performance is emphasized rather than the improvement of the operating efficiency. is driving. In the third cooling operation, a unit refrigerating cycle using the first refrigerant, or a two-part refrigeration cycle in which the first refrigerant is used in the refrigerating cycle on the heat source side, which is the high energy side, and the second refrigerant is used in the refrigerating cycle on the user side, which is the low energy side. A parallel refrigerating cycle by the first refrigerant circuit 10 and the second refrigerating circuit 20 is performed in order to exhibit the ability rather than performing the original refrigerating cycle. In the third cooling operation, as shown in FIG. 17, in the first refrigerant circuit 10, the first outdoor heat exchanger 18 functions as a condenser for the first refrigerant, and the utilization heat exchanger 13 functions as an evaporator for the first refrigerant. In the second refrigerant circuit 20, the second outdoor heat exchanger 23 functions as a radiator for the second refrigerant, and the utilization heat exchanger 13 functions as an evaporator for the second refrigerant. A parallel refrigerating cycle is performed by performing a refrigerating cycle. Specifically, the switching valves 12a, 12b, and 12c of the first switching mechanism 12 are switched to the connected state indicated by solid lines in FIG. 17, and the switching valves 22a, 22b, and 22c of the second switching mechanism 22 are indicated by solid lines in FIG. After switching to the connected state, the pump 92, the first compressor 11, the second compressor 21, and the outdoor fan 9 are driven. Then, the second utilization expansion valve 16 is controlled to a fully open state, the first utilization expansion valve 15 is controlled to a fully closed state, and the valve opening degree of the third utilization expansion valve 14 is set to the first degree of opening for the suction of the first compressor 11 . Control is performed so that the degree of superheat of the refrigerant satisfies a predetermined condition. Furthermore, the first heat source expansion valve 26 is controlled to a fully open state, the third heat source expansion valve 25 is controlled to a fully closed state, and the valve opening degree of the second heat source expansion valve 24 is set to the second Control is performed so that the degree of superheat of the refrigerant satisfies a predetermined condition.

Thereby, the first refrigerant discharged from the first compressor 11 is sent to the first outdoor heat exchanger 18 via the switching valve 12 b of the first switching mechanism 12 . The first refrigerant sent to the first outdoor heat exchanger 18 is condensed by exchanging heat with the outdoor air supplied by the outdoor fan 9 . After passing through the first outdoor heat exchanger 18 , the first refrigerant passes through the second utilization expansion valve 16 , is decompressed in the third utilization expansion valve 14 , and then flows into the utilization heat exchanger 13 . The first refrigerant flowing through the first utilization channel 13a of the heat utilization exchanger 13 exchanges heat with water flowing through the heat load flow channel 13c of the heat utilization heat exchanger 13 of the heat load circuit 90, thereby evaporating. The first refrigerant evaporated in the heat utilization exchanger 13 is sucked into the first compressor 11 via the switching valve 12 a of the first switching mechanism 12 . The second refrigerant discharged from the second compressor 21 is sent to the second outdoor heat exchanger 23 via the switching valve 22b of the second switching mechanism 22 . The second refrigerant sent to the second outdoor heat exchanger 23 exchanges heat with the outdoor air supplied by the outdoor fan 9 to radiate heat. After passing through the second outdoor heat exchanger 23 , the second refrigerant passes through the first heat source expansion valve 26 , is decompressed in the second heat source expansion valve 24 , and then flows into the utilization heat exchanger 13 . The second refrigerant flowing through the second utilization channel 13b of the heat utilization exchanger 13 exchanges heat with water flowing through the heat load flow channel 13c of the heat utilization heat exchanger 13 of the heat load circuit 90, thereby evaporating. In this way, the water cooled by exchanging heat with the two refrigerants, the first refrigerant and the second refrigerant, is sent to the heat load heat exchanger 91 in the heat load circuit 90 to process the cooling load. The second refrigerant evaporated in the heat utilization exchanger 13 is sucked into the second compressor 21 via the switching valve 22 a of the second switching mechanism 22 .

(4-2) Heating operation During the heating operation, the first heating operation, the second heating operation, and the third heating operation are selectively performed.

The first heating operation is performed when the outside air temperature is equal to or higher than a predetermined value.

In the first heating operation, as shown in FIG. 18, in the first refrigerant circuit 10, the utilization heat exchanger 13 functions as a condenser for the first refrigerant, and the first outdoor heat exchanger 18 functions as an evaporator for the first refrigerant. and stops the second compressor 21 in the second refrigerant circuit 20 to perform a unit refrigeration cycle. Specifically, the switching valves 12a and 12b of the first switching mechanism 12 are switched to the connected state indicated by the dashed lines in FIG. is fully opened, the first utilization expansion valve 15 is controlled to be fully closed, and the degree of opening of the second utilization expansion valve 16 is adjusted so that the degree of superheat of the first refrigerant sucked into the first compressor 11 satisfies a predetermined condition. to control.

As a result, the first refrigerant discharged from the first compressor 11 is sent to the first utilization passage 13 a of the utilization heat exchanger 13 via the switching valve 12 a of the first switching mechanism 12 . The first refrigerant flowing through the first utilization channel 13a of the heat utilization exchanger 13 is condensed by exchanging heat with water flowing through the heat load flow channel 13c of the heat utilization heat exchanger 13 of the heat load circuit 90 . The water heated by this heat exchange is sent to the heat load heat exchanger 91 in the heat load circuit 90 to treat the heating load. The first refrigerant condensed in the first utilization flow path 13a of the utilization heat exchanger 13 passes through the third utilization expansion valve 14 and the first branch point A, is decompressed in the second utilization expansion valve 16, and then 1 flows into the outdoor heat exchanger 18 . The first refrigerant sent to the first outdoor heat exchanger 18 evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 9 . The first refrigerant evaporated in the first outdoor heat exchanger 18 is sucked into the first compressor 11 via the switching valve 12b of the first switching mechanism 12 .

The second heating operation is an operation that is performed when the outside air temperature drops below a predetermined value and the unit refrigeration cycle using the first refrigerant in the first refrigerant circuit 10 cannot ensure the capacity. In the second heating operation, as shown in FIG. 19, in the first refrigerant circuit 10, the utilization heat exchanger 13 functions as a condenser for the first refrigerant, and the heat source heat exchanger 17 functions as an evaporator for the first refrigerant. In the second refrigerant circuit 20, the heat source heat exchanger 17 functions as a radiator for the second refrigerant, and the second outdoor heat exchanger 23 functions as an evaporator for the second refrigerant. A two-dimensional refrigeration cycle is performed by performing Specifically, the switching valves 12a, 12b, and 12c of the first switching mechanism 12 are switched to the connected state indicated by broken lines in FIG. 19, and the switching valves 22a, 22b, and 22c of the second switching mechanism 22 are indicated by solid lines in FIG. After switching to the connected state, the pump 92, the first compressor 11, the second compressor 21, and the outdoor fan 9 are driven. Then, the second use expansion valve 16 is controlled to a fully closed state, the third use expansion valve 14 is controlled to a fully open state, and the valve opening degree of the first use expansion valve 15 is set to the first value for suction of the first compressor 11 . Control is performed so that the degree of superheat of the refrigerant satisfies a predetermined condition. Furthermore, the second heat source expansion valve 24 is controlled to a fully closed state, the third heat source expansion valve 25 is controlled to a fully open state, and the valve opening degree of the first heat source expansion valve 26 is set to the second Control is performed so that the degree of superheat of the refrigerant satisfies a predetermined condition.

Thereby, the first refrigerant discharged from the first compressor 11 is sent to the utilization heat exchanger 13 via the switching valve 12 a of the first switching mechanism 12 . The first refrigerant flowing through the first utilization channel 13a of the heat utilization exchanger 13 is condensed by exchanging heat with water flowing through the heat load flow channel 13c of the heat utilization heat exchanger 13 of the heat load circuit 90 . The water heated by this heat exchange is sent to the heat load heat exchanger 91 in the heat load circuit 90 to treat the heating load. After passing through the heat utilization exchanger 13 , the first refrigerant passes through the third utilization expansion valve 14 , is decompressed in the first utilization expansion valve 15 , and then flows into the heat source heat exchanger 17 . The first refrigerant flowing through the first heat source passage 17a of the heat source heat exchanger 17 exchanges heat with the second refrigerant flowing through the second heat source passage 17b and evaporates. The first refrigerant evaporated in the heat source heat exchanger 17 is sucked into the first compressor 11 via the switching valve 12 c of the first switching mechanism 12 . The second refrigerant discharged from the second compressor 21 is sent to the heat source heat exchanger 17 via the switching valve 22 c of the second switching mechanism 22 . The second refrigerant flowing through the second heat source channel 17b of the heat source heat exchanger 17 exchanges heat with the first refrigerant flowing through the first heat source channel 17a, thereby releasing heat. After passing through the heat source heat exchanger 17 , the second refrigerant passes through the third heat source expansion valve 25 and is decompressed in the first heat source expansion valve 26 before flowing into the second outdoor heat exchanger 23 . The second refrigerant sent to the second outdoor heat exchanger 23 evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 9 . The second refrigerant evaporated in the second outdoor heat exchanger 23 is sucked into the second compressor 21 via the switching valve 22b of the second switching mechanism 22 .

The third heating operation is performed when the temperature of the heat medium flowing through the heat load circuit 90 is lower than a predetermined value and the heating load is large, and when the emphasis is placed on demonstrating the ability rather than improving the operating efficiency. is driving. In the third cooling operation, the first refrigerant is used in the refrigeration cycle on the heat source side, which is on the high side, and the second refrigerant is used in the refrigeration cycle on the user side, which is on the low side, rather than the unitary refrigeration cycle using the first refrigerant. A parallel refrigerating cycle by the first refrigerant circuit 10 and the second refrigerating circuit 20 is performed in order to exhibit more capacity than the dual refrigerating cycle. In the third heating operation, as shown in FIG. 20, in the first refrigerant circuit 10, the utilization heat exchanger 13 functions as a condenser for the first refrigerant, and the first outdoor heat exchanger 18 functions as an evaporator for the first refrigerant. In the second refrigerant circuit 20, the utilization heat exchanger 13 functions as a radiator for the second refrigerant, and the second outdoor heat exchanger 23 functions as an evaporator for the second refrigerant. A parallel refrigerating cycle is performed by performing a refrigerating cycle. Specifically, the switching valves 12a, 12b and 12c of the first switching mechanism 12 are switched to the connected state indicated by broken lines in FIG. 20, and the switching valves 22a and 22c of the second switching mechanism 22 are switched to the connected state indicated by broken lines in FIG. 20, the switching valve 22b of the second switching mechanism 22 is switched to the connected state indicated by the solid line in FIG. Then, the third utilization expansion valve 14 is controlled to a fully open state, the first utilization expansion valve 15 is controlled to a fully closed state, and the valve opening degree of the second utilization expansion valve 16 is set to the first degree of opening for suction of the first compressor 11 . Control is performed so that the degree of superheat of the refrigerant satisfies a predetermined condition. Furthermore, the second heat source expansion valve 24 is controlled to a fully open state, the third heat source expansion valve 25 is controlled to a fully closed state, and the valve opening degree of the first heat source expansion valve 26 is set to the second Control is performed so that the degree of superheat of the refrigerant satisfies a predetermined condition.

As a result, the first refrigerant discharged from the first compressor 11 is sent to the utilization heat exchanger 13 via the switching valve 12a of the first switching mechanism 12, and is condensed by exchanging heat with water flowing through the heat load flow path 13c of the utilization heat exchanger 13 of the heat load circuit 90. After passing through the heat utilization exchanger 13 , the first refrigerant passes through the third utilization expansion valve 14 and is decompressed in the second utilization expansion valve 16 before flowing into the first outdoor heat exchanger 18 . The first refrigerant sent to the first outdoor heat exchanger 18 evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 9 . The first refrigerant evaporated in the first outdoor heat exchanger 18 is sucked into the first compressor 11 via the switching valve 12b of the first switching mechanism 12 . The second refrigerant discharged from the second compressor 21 is sent to the utilization heat exchanger 13 via the switching valve 22 a of the second switching mechanism 22 . The second refrigerant flowing through the second utilization channel 13b of the heat utilization exchanger 13 exchanges heat with water flowing through the heat load flow channel 13c of the heat utilization heat exchanger 13 of the heat load circuit 90, thereby releasing heat. The water thus heated by exchanging heat with the two refrigerants, the first refrigerant and the second refrigerant, is sent to the heat load heat exchanger 91 in the heat load circuit 90 to process the heating load. The second refrigerant that has passed through the utilization heat exchanger 13 passes through the second heat source expansion valve 24 , is decompressed in the first heat source expansion valve 26 , and then flows into the second outdoor heat exchanger 23 . The second refrigerant sent to the second outdoor heat exchanger 23 evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 9 . The second refrigerant evaporated in the second outdoor heat exchanger 23 is sucked into the second compressor 21 via the switching valve 22b of the second switching mechanism 22 .

(4-3) Features of the Fourth Embodiment The refrigerating cycle device 1c of the present embodiment can suppress the deterioration of the global environment, as with the refrigerating cycle device 1 of the first embodiment. easy to secure. In addition, in both cooling and heating, not only the unitary refrigerating cycle and the dual refrigerating cycle, but also the parallel refrigerating cycle can be performed, so it is possible to secure the capacity according to the situation.

(Appendix)
Although embodiments of the present disclosure have been described above, it will be appreciated that various changes in form and detail may be made without departing from the spirit and scope of the present disclosure as set forth in the appended claims. .

1, 1a, 1b, 1c: refrigeration cycle device 12: first switching mechanism 12x: first switching mechanism 13: utilization heat exchanger 13a: first utilization flow path 13b: second utilization flow path 13c: heat load flow path 14 : Third use expansion valve 15 : First use expansion valve 16 : Second use expansion valve 17 : Heat source heat exchanger (cascade heat exchanger)
17a: first heat source channel (first cascade channel)
17b: Second heat source channel (second cascade channel)
18: first outdoor heat exchanger 20: second refrigerant circuit 21: second compressor 23: second outdoor heat exchanger 24: second heat source expansion valve 25: third heat source expansion valve 26: first heat source expansion valve 90 : Heat load circuit 91 : Heat load heat exchanger 92 : Pump

JP 2015-197254 A

Claims (16)

By performing a dual refrigeration cycle including a user side refrigeration cycle using a first refrigerant of 1 MPa or less at 30° C. and a heat source side refrigeration cycle using a second refrigerant of 1.5 MPa or more at 30° C. heating operation,
Cooling operation is performed by performing a unit refrigeration cycle using the first refrigerant,
A refrigeration cycle device (1). A first cascade flow path (17a) for flowing the first refrigerant during the heating operation and a second cascade flow path for flowing the second refrigerant during the heating operation are independent of the first cascade flow path (17a). a cascade heat exchanger (17) having a flow path (17b) for exchanging heat between the first refrigerant and the second refrigerant;
The refrigeration cycle apparatus according to claim 1. A utilization heat exchanger (13) in which the first refrigerant releases heat during the heating operation,
During the heating operation, the first refrigerant evaporates when passing through the first cascade flow path (17a), and heat is released when the second refrigerant passes through the second cascade flow path (17b).
The refrigeration cycle apparatus according to claim 2. a utilization heat exchanger (13) in which the first refrigerant evaporates during the cooling operation;
a first outdoor heat exchanger (18) in which the first refrigerant releases heat during the cooling operation;
with
The refrigeration cycle apparatus according to any one of claims 1 to 3. A second outdoor heat exchanger (23) in which the second refrigerant evaporates during the heating operation,
The refrigeration cycle apparatus according to any one of claims 1 to 4. By performing a dual refrigeration cycle including a user side refrigeration cycle using a first refrigerant of 1 MPa or less at 30° C. and a heat source side refrigeration cycle using a second refrigerant of 1.5 MPa or more at 30° C. heating operation,
Cooling operation is performed by performing a dual refrigeration cycle including a user-side refrigeration cycle using the second refrigerant and a heat source-side refrigeration cycle using the first refrigerant,
A refrigeration cycle device (1a, 1b, 1c). a first cascade flow path (17a) for flowing the first refrigerant; and a second cascade flow path (17b) for flowing the second refrigerant, which is independent of the first cascade flow path. a cascade heat exchanger (17) for exchanging heat between the first refrigerant and the second refrigerant;
The refrigeration cycle apparatus according to claim 6. a first use channel (13a) for flowing the first refrigerant; and a second use channel (13b) for flowing the second refrigerant, which is independent of the first use channel. a utilization heat exchanger (13) comprising
The refrigeration cycle apparatus according to claim 7. During the heating operation, the first refrigerant evaporates when passing through the first cascade flow path (17a), and the second refrigerant radiates heat when passing through the second cascade flow path (17b). 1. Heat is released when the refrigerant passes through the first use channel (13a),
The refrigeration cycle apparatus according to claim 8. During the cooling operation, the first refrigerant evaporates when passing through the first cascade passage (17a), the second refrigerant radiates heat when passing through the second cascade passage (17b), and the second refrigerant evaporates when passing through the first cascade passage (17a). 2 refrigerant evaporates when passing through the second utilization channel (13b);
The refrigeration cycle apparatus according to claim 8 or 9. During the cooling operation, the first refrigerant evaporates when passing through the first use channel (13a), and the second refrigerant evaporates when passing through the second use channel (13b).
The refrigeration cycle apparatus according to any one of claims 8 to 10. During the heating operation, heat is released when the first refrigerant passes through the first use channel (13a), and heat is released when the second refrigerant passes through the second use channel (13b).
The refrigeration cycle apparatus according to any one of claims 8 to 11. A first outdoor heat exchanger (18) in which the first refrigerant releases heat during the cooling operation,
The refrigeration cycle apparatus according to any one of claims 6 to 12. A second outdoor heat exchanger (23) in which the second refrigerant evaporates during the heating operation,
The refrigeration cycle apparatus according to any one of claims 6 to 13. The first refrigerant contains at least one of R1234yf and R1234ze,
The refrigeration cycle apparatus according to any one of claims 1 to 14. The second refrigerant contains carbon dioxide,
The refrigeration cycle apparatus according to any one of claims 1 to 15.

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