Patent ID: 8181478

Claim:
A refrigeration system comprising: a compressor having a suction port, a discharge port, and a first intermediate-pressure port in communication with a first intermediate-pressure location of said compressor, said first intermediate-pressure location having a first intermediate pressure during operation of said compressor; a refrigerant flowing through said compressor and compressed from a suction pressure to a discharge pressure greater than said suction pressure and having a nominal discharge temperature, said first intermediate pressure being greater than said suction pressure and less than said discharge pressure; a single-phase cooling liquid received in said first intermediate-pressure port and injected into said first intermediate-pressure location and compressed to said discharge pressure and said nominal discharge temperature, said cooling liquid absorbing heat within said compressor caused by compression of said refrigerant and said cooling liquid; a separator separating said refrigerant and said cooling liquid and operating at a temperature and pressure approximately equal to said discharge temperature and pressure; a first heat exchanger receiving a generally refrigerant-free flow of said cooling liquid from said separator and removing heat to reduce a temperature of said cooling liquid; a throttle device disposed in a flow path between said first heat exchanger and said first intermediate-pressure port and reducing a pressure of said cooling liquid to lower than said discharge pressure and greater than said first intermediate pressure of said first intermediate-pressure location of said compressor, wherein a fluid injected into said first intermediate-pressure location through said first intermediate-pressure port is substantially said single-phase cooling liquid and a pressure difference between said discharge pressure and said first intermediate pressure causes said single-phase cooling liquid to be injected into said first intermediate-pressure location; a vapor-injection port on said compressor communicating with a second intermediate-pressure location of said compressor, said second intermediate pressure location having a second intermediate pressure during operation of said compressor greater than said suction pressure and less than said discharge pressure, and wherein a refrigerant stream flows out of said separator and a portion of said refrigerant stream is expanded and injected into said second intermediate pressure location of said compressor through said vapor-injection port in vapor form, wherein an entirety of said refrigerant stream is expanded through an expansion device and flows into a flash tank wherein a vapor portion of said refrigerant in said flash tank is injected into said compressor through said vapor-injection port.