Abstract
A Low-grade Thermal Energy Conversion (LTEC) is refocused as one of the renewable energy. For the LTEC and Refrigerator/Heat Pump, it is very important to enhance the heat transfer on heat exchanger though the available temperature deference is smaller than conventional thermal system. In last study, by using micro fabrication surface on plate evaporator, heat transfer coefficient of HFC245fa is enhanced compared with normal surface plate evaporator. In this paper, the experimental performance test as evaporator is evaluated on comparison with HFC245fa and HFC 134a The results show the boiling heat transfer coefficient of HFC 134a was larger than that of HFC245fa Heat transfer coefficient of these working fluids is estimated using Lockhart-Martinelli parameter.