Performance analysis for binary mixtures based on R245fa using in high temperature heat pumps

Abstract As a reliable waste heat recovery device, the high-temperature heat pump (HTHP) is increasingly used in industrial enterprises. The selection of refrigerant is one of the most important factors to determine the safe, reliability and economic operation of the HTHP. Starting from this perspective, a simple new method based on the characteristics of the extrema of volumetric heat capacity and coefficient of performance was developed to obtain the appropriate composition of the binary mixtures. Then, the working fluids including four binary mixtures with appropriate composition and R245fa were investigated experimentally in different high-temperature conditions. The heating temperature of the HTHP system is 80–100 °C and the temperature lift between the heat source and the heat sink was kept at 35 °C in the experiment. Experimental results showed that the working fluids HG-1 had good COP due to the low power consumption of compressor, when the heat sink temperature was 100 °C, the COP of HG-1was higher than 4.9, and the comprehensive performance was better than that of R245fa. In addition, the exergoeconomic performance of different working fluids was calculated based on experimental data. The results showed that HG-1 has the lowest exergy destruction and extra cost rate of overall system compared with other binary mixtures, which were 909.5 W and 0.117 $/hr, respectively at the heat output temperature of 100 °C. All the results demonstrated the feasibility and reliability of HG-1 as a new high-temperature refrigerant to produce heat at the temperature of 80–100 °C.