Patent ID: 7721562
Filing Date: 2010-05-25
Classification: B60H,F25B

Abstract:
1. A refrigerant system comprising: at least one compressor having a multi-speed drive for providing multiple speeds for said compressor, and said compressor being provided with a suction port, an intermediate pressure port and discharge port; a condenser downstream of said compressor, a main expansion device downstream of said condenser, an evaporator downstream of said main expansion device, with an economizer circuit containing an economizer expansion device and an economizer heat exchanger and positioned intermediate to said condenser and said evaporator, said economizer circuit selectively returning a tapped refrigerant to said compressor; a control for selectively operating said economizer circuit to deliver a tapped refrigerant through said economizer heat exchanger, and back to said compressor, and said control also selecting a speed of said compressor to achieve various levels of capacity, said control being programmed to select between available modes of operation, said available modes of operation including at least operation with said economizer circuit operational, and without said economizer circuit operational, and said control first selecting a mode to best achieve desired conditions for an environment to be conditioned, then varying a speed of the motor if further variation is required to meet the desired conditions; and there is a suction modulation valve located downstream of said evaporator and its operation is one of the modes of operation.