Patent ID: 7775057
Filing Date: 2010-08-17
Classification: F25B

Abstract:
1. A method of controlling a refrigerant system to meet a cooling load that can vary from a range of lower loads to a higher load, wherein the system includes a compressor that forces refrigerant in series through an expansion valve, an evaporator, and the compressor, the method comprising: monitoring a primary thermodynamic variable associated with the refrigerant system; monitoring a secondary thermodynamic variable associated with the refrigerant system; establishing a limit for the secondary thermodynamic variable; comparing the secondary thermodynamic variable to the limit to create a comparison; based on the comparison, selectively operating the refrigerant system in a normal operating mode and a capped operating mode; when operating the refrigerant system in the normal operating mode, controlling at least one of the compressor and the expansion valve in response to the primary thermodynamic variable so that the refrigerant system can address the cooling load within the range of tower loads; and when operating the refrigerant system in the capped operating mode, controlling at least one of the compressor and the expansion valve in response to the secondary thermodynamic value so that the refrigerant system can at least partially address the cooling load at the higher load, wherein the refrigerant system continues operating but does so at a restricted capacity that can help prevent the refrigerant from being carried over in a liquid state from the evaporator into the compressor when the refrigerant system is subject to the higher load.