냉장고 증발기 제상용 버블젯 루프 히트파이프의 열전달 성능 분석

Abstract

The frost on refrigerator evaporator occur many problems which are reducing refrigerating capacity, increasing inner temperature and power consumption. Conventional defrost method in refrigerator is using electric heater. But it needs high temperature to defrost and wastes electricity because frost on evaporator is non-uniform. In order to resolve these problems, Bubble Jet Loop Heat Pipe(BJLHP) applicable to defrost on evaporator was developed. Working fluid is evaporated in the BJLHP's evaporating part, then condensed in condensing part of low temperature. It can be possible that the BJLHP conserves energy. In this study, three experiments were conducted to know the thermal performance of the BJLHP. The first experiment was to search the best charging ratio of working fluid when the working fluid was R-134a. In result, effective thermal conductivity and standard deviation of temperature measurement points were the best when the charging ratio was 35%vol.. Second experiment was conducted to know each thermal performances and the best one when the clearance(between tube and heater in evaporating part) was changed using R-134a 35%vol. as working fluid. In result, when the clearance was 2.05mm(tube inside diameter 14.1mm, heater diameter 10mm), effective thermal conductivity was the best and the standard deviation was second best. Finally, third experiment was to know thermal performance when the clearance and the charging ratio were changed using R-600a as working fluid. In result, the best clearance was 2.05mm and charging ratio was 35%vol. It was the same result when working fluid was R-134a.