Patent ID: 7997091
Filing Date: 2011-08-16
Classification: F25B

Abstract:
1. A refrigerant cycle comprising: at least one compressor, said compressor delivering refrigerant to a first heat exchanger, said refrigerant passing from said first heat exchanger to a main expansion device, and from said main expansion device to a second heat exchanger, said refrigerant passing from said second heat exchanger back to said compressor; an economizer circuit incorporated between said first heat exchanger and said main expansion device, said economizer circuit including a tap for tapping a refrigerant flow from a main refrigerant flow line, said tapped refrigerant from refrigerant in said main refrigerant flow line both passing through an economizer heat exchanger, with said tapped refrigerant passing through an auxiliary expansion device prior to passing through said economizer heat exchanger; and said auxiliary expansion device having a variable opening, a control for said economizer circuit, said control being operable to determine a desired condition for said refrigerant cycle, and modulate the refrigerant passing through said auxiliary expansion device to achieve said desired condition by varying the opening of said auxiliary expansion device, and said desired condition is head pressure.