JPS6449852A - Method of controlling variable capacity compressor in chilling unit - Google Patents

Abstract

PURPOSE: To improve the feeling of cooling by decreasing capacity control constants when the supply air temperature at the outlet of an evaporator is within an allowable temperature region including a target temperature otherwise increasing the capacity control constants and operating a capacity control amount thereby suppressing significant hunting of the supply air temperature. CONSTITUTION: When a measured supply air temperature Tf does not exceeds an allowable temperature region ΔT, a temperature fluctuation comparing/deciding means 25 outputs a normal signal S1 and a capacity control constant altering means 26 outputs a capacity control constant small signal S3. Based on the small signal S3, an operation controller 1-7 operates a capacity control amount to produce a capacity control signal proportional thereto thus controlling a variable capacity compressor 2. When the measured supply air temperature Tt exceeds the allowable temperature region ΔT, the temperature fluctuation comparing/deciding means 25 outputs an abnormal signal S2 and the capacity control constant altering means 26 outputs a capacity control constant large signal S4. Based on the large signal S4, the operation controller 17 operates a capacity control amount to produce a capacity control signal proportional thereto thus controlling the variable capacity compressor 2.