Experimental study on diffusion absorption refrigeration cycle using low GWP refrigerants

Compared to the conventional absorption refrigeration systems, diffusion absorption refrigeration (DAR) system consists of three components of the working fluids: refrigerant, absorbent, and auxiliary gas. In general, the DAR uses ammonia and water as the working fluids. However, ammonia is flammable, explosive, toxic, and d by high pressure gas safety management act. The main objective of this study is to select a low GWP refrigerant, its pair absorbent and auxiliary gas by experimental investigation. During the experiments, types of the refrigerant-absorbent pair, concentration of the refrigerant, pressure, and temperature are considered as the key parameters to obtain the maximum coefficient of performance (COP) and a low evaporation temperature. The optimum conditions for the key parameters were determined by experiments. It was found that R1234ze(E) gave the best COP with the evaporation temperature of -12.2 ^o C.