Performance estimation of ejector cycles using ethers and fluorinated ethers as refrigerants

Computer software, based on the theoretical model of Huang et al. (1999) with thermodynamic properties of selected refrigerants, was prepared. The investigation was focused on alternative refrigerants that belong to the groups of ethers and fluorinated ethers. The main purpose of the paper was to check the possibility of cooperating the above substances with an ejector cooling system powered by a high-temperature heat source. A series of calculations were carried out for the generator temperature from 60 degrees C to 165 degrees C, with assumed temperatures of evaporation of 10 degrees C and condensation of 40 degrees C. The analysis revealed that there is no single refrigerant that ensures the efficient operation of the system in the whole range of primary vapor temperatures. Each substance has its own maximum entrainment ratio and COP at its individual optimum temperature. The maximum COP values were obtained for dimethyl ether and diethyl ether, and reached 0.30 and 0.25 respectively.