Refrigeration cycle device
Even if, in decompressing a refrigerant by an expansion mechanism, the temperature of the refrigerant cannot be sufficiently reduced, in order to increase the evaporation capacity of a use-side heat exchanger, a main expansion mechanism including an expansion element of a rotary or scroll type that causes power to be produced by decompressing a main refrigerant is provided at a main refrigerant circuit in which the main refrigerant circulates. Further, a sub-refrigerant circuit that differs from the main refrigerant circuit and in which a sub-refrigerant circulates is provided. A sub-use-side heat exchanger that is provided at the sub-refrigerant circuit and that functions as an evaporator of the sub-refrigerant is caused to function as a heat exchanger that cools the main refrigerant that flows between the main expansion mechanism and a main use-side heat exchanger.
1. A refrigeration cycle device comprising:
a main refrigerant circuit having
a main compressor that compresses a main refrigerant,
a main heat-source-side heat exchanger that functions as a radiator of the main refrigerant,
a main use-side heat exchanger that functions as an evaporator of the main refrigerant,
a main expansion mechanism including an expansion element of a rotary or scroll type that causes power to be produced by decompressing the main refrigerant that flows between the main heat-source-side heat exchanger and the main use-side heat exchanger, and
a main intermediate-pressure adjusting valve between the main expansion mechanism and the main use-side heat exchanger,
wherein the main refrigerant circuit has a sub-use-side heat exchanger that functions as a cooler of the main refrigerant that flows between the main expansion mechanism and the main use-side heat exchanger;
the refrigeration cycle device further comprising:
a sub-refrigerant circuit having
a sub-compressor that compresses a sub-refrigerant,
a sub-heat-source-side heat exchanger that functions as a radiator of the sub-refrigerant, and
the sub-use-side heat exchanger that functions as an evaporator of the sub-refrigerant and that cools the main refrigerant that flows between the main expansion mechanism and the main use-side heat exchanger; and
the refrigerant cycle device further comprising
a controller that controls the main intermediate-pressure adjusting valve in accordance with an input power of the sub-refrigerant circuit.
2. The refrigerant cycle device according to claim 1 , wherein the controller obtains the input power of the sub-refrigerant circuit from outside air temperature or a current value of the sub-compressor.
3. The refrigeration cycle device according to claim 1 , wherein the main intermediate-pressure adjusting valve is provided at a portion of the main refrigerant circuit, the portion being between the sub-use-side heat exchanger and the main use-side heat exchanger, and
wherein, when the input power of the sub-refrigerant circuit increases, the controller decreases an opening degree of the main intermediate-pressure adjusting valve.
4. The refrigerant cycle device according to claim 3 , wherein, when the input power of the sub-refrigerant circuit decreases, the controller unit increases the opening degree of the main intermediate-pressure adjusting valve.
5. The refrigeration cycle device according to claim 1 , wherein the main refrigerant circuit has a gas-liquid separator between the main expansion mechanism and the main use-side heat exchanger, the gas-liquid separator causing the main refrigerant decompressed at the main expansion mechanism to separate gas and liquid,
wherein a degassing pipe that extracts the main refrigerant in a gas state and sends the main refrigerant in the gas state toward a suction side of the main compressor is connected to the gas-liquid separator,
wherein the main intermediate-pressure adjusting valve is provided at the degassing pipe, and
wherein, when the input power of the sub-refrigerant circuit increases, the controller decreases an opening degree of the main intermediate-pressure adjusting valve.
6. The refrigerant cycle device according to claim 5 , wherein, when the input power of the sub-refrigerant circuit decreases, the controller increases the opening degree of the main intermediate-pressure adjusting valve.
7. The refrigeration cycle device according to claim 1 , wherein the main compressor includes a low-stage-side compression element of a rotary or scroll type that compresses the main refrigerant and a high-stage-side compression element of a rotary or scroll type that compresses the main refrigerant discharged from the low-stage-side compression element.
8. The refrigeration cycle device according to claim 1 , wherein the main refrigerant is carbon dioxide, and
wherein the sub-refrigerant is a HFC refrigerant, a HFO refrigerant, or a mixture refrigerant in which the HFC refrigerant and the HFO refrigerant are mixed, each of the HFC refrigerant, the HFO refrigerant, and the mixture refrigerant having a GWP that is 750 or less.
9. The refrigeration cycle device according to claim 1 , wherein the main refrigerant is carbon dioxide, and
wherein the sub-refrigerant circuit utilizes a natural refrigerant such that the sub-refrigerant circuit has a coefficient of performance that is higher than the coefficient of performance of the main refrigerant circuit using a carbon dioxide refrigerant.
10. The refrigeration cycle device according to claim 2 , wherein the main intermediate-pressure adjusting valve is provided at a portion of the main refrigerant circuit, the portion being between the sub-use-side heat exchanger and the main use-side heat exchanger, and
wherein, when the input power of the sub-refrigerant circuit increases, the controller decreases an opening degree of the main intermediate-pressure adjusting valve.
11. The refrigerant cycle device according to claim 10 , wherein, when the input power of the sub-refrigerant circuit decreases, the control unit increases the opening degree of the main intermediate-pressure adjusting valve.
12. The refrigeration cycle device according to claim 2 , wherein the main refrigerant circuit has a gas-liquid separator between the main expansion mechanism and the main use-side heat exchanger, the gas-liquid separator causing the main refrigerant decompressed at the main expansion mechanism to separate gas and liquid,
wherein a degassing pipe that extracts the main refrigerant in a gas state and sends the main refrigerant in the gas state toward a suction side of the main compressor is connected to the gas-liquid separator,
wherein the main intermediate-pressure adjusting valve is provided at the degassing pipe, and
wherein, when the input power of the sub-refrigerant circuit increases, the controller decreases an opening degree of the main intermediate-pressure adjusting valve.
13. The refrigerant cycle device according to claim 12 , wherein, when the input power of the sub-refrigerant circuit decreases, the controller increases the opening degree of the main intermediate-pressure adjusting valve.
14. The refrigeration cycle device according to claim 2 , wherein the main compressor includes a low-stage-side compression element of a rotary or scroll type that compresses the main refrigerant and a high-stage-side compression element of a rotary or scroll type that compresses the main refrigerant discharged from the low-stage-side compression element.
15. The refrigeration cycle device according to claim 3 , wherein the main compressor includes a low-stage-side compression element of a rotary or scroll type that compresses the main refrigerant and a high-stage-side compression element of a rotary or scroll type that compresses the main refrigerant discharged from the low-stage-side compression element.
16. The refrigeration cycle device according to claim 4 , wherein the main compressor includes a low-stage-side compression element of a rotary or scroll type that compresses the main refrigerant and a high-stage-side compression element of a rotary or scroll type that compresses the main refrigerant discharged from the low-stage-side compression element.
17. The refrigeration cycle device according to claim 5 , wherein the main compressor includes a low-stage-side compression element of a rotary or scroll type that compresses the main refrigerant and a high-stage-side compression element of a rotary or scroll type that compresses the main refrigerant discharged from the low-stage-side compression element.
18. A refrigeration cycle device comprising:
a main refrigerant circuit having
a main compressor that compresses a main refrigerant,
a main heat-source-side heat exchanger that functions as a radiator of the main refrigerant,
a main use-side heat exchanger that functions as an evaporator of the main refrigerant,
a main expansion mechanism including an expansion element of a rotary or scroll type that causes power to be produced by decompressing the main refrigerant that flows between the main heat-source-side heat exchanger and the main use-side heat exchanger, and
a main intermediate-pressure adjusting valve between the main expansion mechanism and the main use-side heat exchanger,
wherein the main refrigerant circuit has a sub-use-side heat exchanger that functions as a cooler of the main refrigerant that flows between the main expansion mechanism and the main use-side heat exchanger;
the refrigeration cycle device further comprising:
a sub-refrigerant circuit having
a sub-compressor that compresses a sub-refrigerant,
a sub-heat-source-side heat exchanger that functions as a radiator of the sub-refrigerant, and
the sub-use-side heat exchanger that functions as an evaporator of the sub-refrigerant and that cools the main refrigerant that flows between the main expansion mechanism and the main use-side heat exchanger; and
the refrigeration cycle device further comprising:
a controller that controls the main intermediate-pressure adjusting valve,
wherein the controller controls an opening degree of the main intermediate-pressure adjusting valve inversely to the outside air temperature such that as the outside air temperature rises, the main intermediate-pressure adjusting valve is further closed, and as the outside air temperature falls, the main intermediate-pressure adjusting valve is further opened.
19. The refrigeration cycle device according to claim 18 , wherein the main compressor includes a low-stage-side compression element of a rotary or scroll type that compresses the main refrigerant and a high-stage-side compression element of a rotary or scroll type that compresses the main refrigerant discharged from the low-stage-side compression element.