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FOREIGN PATENT DOCUMENTS
0176363 7/1990 Japan 62/201
Primary Examiner—William E. Wayner
Attorney, Agent, or Firm—William J. Beres; William
O'Driscoll; Peter D. Ferguson
[57] ABSTRACT
A method of controlling the capacity of a chiller system, the chiller system including a circularly linked compressor, condenser, expansion device, and evaporator. The method comprises the steps of: measuring a first chiller system parameter; determining a first parameter error as a function of the difference between the first parameter and a first setpoint; measuring a second chiller system parameter; determining a second parameter error as a function of the difference between the second parameter and a second setpoint; providing a first mode of capacity control where the compressor is modulated in response to the first parameter error and the expansion valve is modulated in response to the second parameter error; and providing a second mode of capacity control where the compressor is maintained at a minimum capacity and the expansion valve is modulated in response to the first parameter error.
19 Claims, 3 Drawing Sheets
