A transcritical vapor compression system includes a fluid circuit circulating a refrigerant in a closed loop. The fluid circuit has operably disposed therein, in serial order, a compressor, a first heat exchanger, at least one non-variable expansion device and a second heat exchanger. The compressor compresses the refrigerant from a low pressure to a supercritical pressure. The first heat exchanger is positioned in a high pressure side of the fluid circuit. The second heat exchanger is positioned in a low pressure side of the fluid circuit. The at least one non-variable expansion device reduces the pressure of the refrigerant from a supercritical pressure to a relatively lower pressure. A refrigerant storage vessel is in fluid communication with the fluid circuit and contains a variable mass of refrigerant whereby the capacity of the system may be controlled.