초록 ▼

A variable capacity compression type cooling system improves operating efficiency by modulating speed of the condenser pump motor and/or a cooling tower fan motor, in response to the loading level on the cooling apparatus. In contrast to known control strategies that rely on refrigerant gas pressure

A variable capacity compression type cooling system improves operating efficiency by modulating speed of the condenser pump motor and/or a cooling tower fan motor, in response to the loading level on the cooling apparatus. In contrast to known control strategies that rely on refrigerant gas pressure or temperature changes, the present system controls the heat rejection components in direct response to the current loading level on the cooling system. Cooling system loading is indicated, e.g,. by the current power ratio (percent of maximum) being utilized by the air conditioning compressor. The new strategy sets operation of the heat rejection components at a power setting that is a fixed ratio of the cooling system current power ratio (subject to limits). For a cooling tower, the control is applied to both the cooling tower fan(s) and the condenser pump(s). For small systems, a single variable-speed drive can be used for both the refrigerant compression device and the heat rejection component(s). The invention provides significant improvements in efficiency by reducing power consumed in operation of the various components of the system, particularly under reduced-loading conditions.

대표청구항 ▼

[ What is claimed is:] [1.]1. A variable capacity, compression type cooling system comprising:a heat absorbing circuit (302);a heat rejection circuit coupled to the heat absorbing circuit for rejecting into the environment at least a portion of heat absorbed by the heat absorbing circuit;the heat re

[ What is claimed is:] [1.]1. A variable capacity, compression type cooling system comprising:a heat absorbing circuit (302);a heat rejection circuit coupled to the heat absorbing circuit for rejecting into the environment at least a portion of heat absorbed by the heat absorbing circuit;the heat rejection circuit including:a compressor (310) and a motor (309) connected for driving the compressor;a first variable-frequency drive circuit (308) coupled to the compressor motor;an air cooled condenser (320);a variable-speed fan (334) for driving air over the air cooled condenser;a second variable-frequency drive circuit (335) for powering the fan motor;means for determining a present load (316) on the cooling; andmeans for controlling (317) the second variable-frequency drive circuit (335) in response to the present load on the cooling system so as to regulate operation of the variable-speed fan in response to the load on the compressor.