Patent ID: 8769983

Claim:
A refrigeration cycle apparatus, comprising: a first compressor for increasing a pressure of a low-pressure refrigerant, which is a refrigerant on a low pressure side, to output an intermediate-pressure refrigerant, which is the refrigerant of an intermediate pressure; a second compressor connected in series to the first compressor, for increasing a pressure of the intermediate-pressure refrigerant to output a high-pressure refrigerant, which is the refrigerant on a high pressure side; a first heat-source-side heat exchanger which is connected in series to the second compressor and through which the high-pressure refrigerant flows; a high and low pressure heat exchanger connected in series to the first heat-source-side heat exchanger that exchanges heat between the high-pressure refrigerant and a reduced-pressure refrigerant from a branch of a high-pressure refrigerant line at an inlet portion of the high and low-pressure heat exchanger; an expander connected in series to the high and low pressure heat exchanger, which reduces a pressure of the high-pressure refrigerant to output the low-pressure refrigerant and drives the second compressor by power recovered in the pressure reduction; a load-side heat exchanger connected in series to the expander, an expansion valve arranged in the branch of high-pressure refrigerant line before the inlet portion of the high and low pressure heat exchanger that reduces the pressure of the high-pressure refrigerant to the reduced-pressure refrigerant adjusting a density of the refrigerant flowing in the expander so that the power recovered by the expander and power required by the second compressor match; and the expander and the second compressor are directly connected by a shaft.