Patent ID: 6694750
Filing Date: 2004-02-24
Classification: F04C,F25B

Abstract:
A refrigeration system comprising:a compressor for compressing a refrigerant to a high pressure, said compressor including a discharge portion, a suction port, a high pressure economizer port, and a low pressure economizer port, and said refrigerant exits said compressor through said discharge port; a condenser for cooling said refrigerant; a high pressure economizer heat exchanger, said refrigerant being split into a fist high passage provided with a high pressure expansion device and a second high passage and then exchanging heat therebetween in said high pressure economizer heat exchanger, said first high passage returning to said compressor through said high pressure economizer port and said second high passage flowing to a low pressure economizer heat exchanger; said low pressure economizer heat exchanger, said refrigerant from said second high passage being split into a first low passage provided with a low pressure expansion device and a second low passage and then exchanging heat therebetween in said low pressure economizer heat exchanger, said first low passage returning to said compressor through said low pressure economizer port and said second low passage flowing to an expansion device; said expansion device for reducing said refrigerant to a low pressure; an evaporator for evaporating said refrigerant, and said refrigerant from said evaporator enters said compressor through said suction port; a first valve to control a flow of said refrigerant between said high pressure economizer port and said low pressure economizer port of said compressor; and a second valve to control a flow of said refrigerant between said low pressure economizer port and said suction port of said compressor.