Patent ID: 7600390

Claim:
A method of changing system cooling capacity in a transcritical vapor compression system without changing the mass flow rate through the system, said method comprising: providing a fluid circuit circulating a refrigerant in a closed loop, the fluid circuit having operably disposed therein, in serial order, a first compressor, an intercooler, a second compressor, a first heat exchanger, an expansion device and a second heat exchanger; compressing the refrigerant from a low pressure to an intermediate pressure in said first compressor; then compressing the refrigerant from the intermediate pressure to a supercritical pressure in the second compressor; then decreasing the temperature of the refrigerant in the first heat exchanger; then passing the refrigerant through the expansion device and reducing the pressure of the refrigerant in the expansion device; then passing the refrigerant through a second heat exchanger to the inlet of the first compressor; and while holding the capacity of the first compressor constant, one of reducing or increasing the capacity of the second compressor to thereby increase or decrease, respectively, the pressure and density of the refrigerant in the intercooler which reduces or increases, respectively, the supercritical pressure of the refrigerant in the first heat exchanger to thereby increase or decrease, respectively, the enthalpy of the refrigerant at the output of the expansion device such that the cooling capacity of the system is decreased or increased, respectively, without changing the mass flow rate through the system.