Patent ID: 8561425

Claim:
A refrigerant vapor compression system comprising: a refrigerant circuit including a refrigerant compression device, a refrigerant cooling heat exchanger for passing refrigerant received from said compression device at a high pressure in heat exchange relationship with a cooling medium, a refrigerant heating heat exchanger for passing refrigerant at a low pressure refrigerant in heat exchange relationship with a heating medium, and a primary expansion device disposed in the refrigerant circuit downstream of said refrigerant cooling heat exchanger and upstream of said refrigerant heating heat exchanger; a first economizer circuit including a refrigerant-to-refrigerant heat exchanger economizer having a first refrigerant pass disposed in the refrigerant circuit downstream of said refrigerant cooling heat exchanger and upstream of said primary expansion device; a second economizer circuit including a flash tank economizer disposed in the refrigerant circuit downstream of said refrigerant cooling heat exchanger and upstream of said primary expansion device, said flash tank economizer and said refrigerant-to-refrigerant economizer disposed in said refrigerant circuit in a series refrigerant flow relationship; and a secondary expansion device disposed in the refrigerant circuit in operative association with and upstream with of said flash tank economizer.