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In a cold chain, the refrigerator is also employed for defrosting, by using an electric heater, which consumes 15% of the power for the system operation. In this study, the condensation heat of the refrigerant was suggested as the heat source of defrosting heat, instead of that from an electric defrost heater. The heat for defrosting was stored to a phase change material (PCM, NMP：52℃) in thermal storage, and was periodically supplied to the evaporator by a circulation loop of brine. As a result, a defrost time by the PCM was obtained that was less than or equal to that by the electric heater. Moreover, power consumption during defrosting was saved by up to 99% of that of the electric heater.Key words Waste heat(폐열), Defrost(제상), PCM(상변화물질), Heat storage(축열), Cold storage(저온저장) †Corresponding author, E-mail: ckang@jbnu.ac.kr 은 서리 성장에 의한 열교환기의

Weight loss that influences the quality and farmer incomes is affected by storage environment of agricultural products. The interior of storage should be maintained at high humidity to prevent weight loss of products which contains a lot of moisture. The research had constantly proceeded with change of the heat exchanger surface areas, humidity systems to maintain high humidity within storage. And weight loss prediction carry out by vapor pressure deficit (VPD) and K-value. Relative humidity that exerts an effect weight loss of crop be influenced by storage temperature, leak state and volume of product. When weight loss predicts, different conditions of these factors derive the error. In case of CA storage, ways of forecasting the weight loss become easier than cold storage due to sealed storage with external environment during storage period. In this study, Apples were stored in purge-type CA storage and weight loss has been predicted by using operating characteristics of refrigerator system and environmental conditions. And it was compared with actual weight loss. As a result, humidity variation in the storage fluctuates with operation of unit-cooler. Furthermore unit-cooler operation factor is influenced by outside temperature and respiration heat. Prediction value of weight loss according to temperature and humidity has been most accurately predicted. Prediction value through measured defrosting water shows unit-cooler work quality. K-value needs verification to calculate of VPD method. 