PERFORMANCE CHARACTERISTICS OF COOLER CONTROLED CAPACITY USING HOT-GAS BYPASS

摘要

This paper presents the performance characteristics of hot-gas bypass capacity system for water cooler of machine tool. The system was designed for hot-gas bypass from outlet of compressor to the inlet of evaporator. The water cooler was used to reduce thermal deformation and contraction due to high speed of machine tools. The results show that maximum refrigeration capacity of 4.3kW was obtained from 0 step of electronic expansion valve(EEV) in the chilled water outlet temperature of 25°C and the chamber temperature of 25°C and minimum refrigeration capacity of 0.41kW was obtained from 375 steps of EEV at the chilled water outlet temperature of 16°C. Chilled water outlet temperature of 19°C and 16°C were not obtained from over 375 steps of EEV in the chamber temperature of 25°C. In this study, an EEV was used to control capacity for water cooler. The ranges of capacity control were from 100 to 10% to set the chilled water temperature of 25°C at the outdoor temperature of 35°C of general machine tools in Korea. It was found that there is the possibility of capacity control with hot-gas bypass system.