Experimental research on the performance of the diffusion absorption refrigerator with mixed fluoride refrigerants

•Mixed fluoride refrigerants were experimentally employed in a DAR system.•Low refrigerating temperature (−28.8 °C) was achieved.•The generating temperature could be as low as 83.3 °C. A diffusion absorption refrigerator (DAR) operating with mixed fluoride refrigerants was built to obtain low refrigerating temperature at low generating temperature. Two groups of mixed fluoride refrigerants, R23/R134a and R23/R32/R134a, were tested experimentally. The N,N-dimethylformamide (DMF) and helium were used as the absorbent and inert gas, respectively. For the DAR with R23/R134a, the refrigerating temperature was not obviously influenced by the concentration of R23 in the mixed refrigerant vapor or the amounts of helium. For the DAR with R23/R32/R134a, an optimal concentration of R32 in the mixed refrigerant vapor and an optimal pressure were both found to achieve the lowest refrigerating temperature which was −28.8 °C at a generating temperature of 106.9 °C, and a refrigerating temperature of −23.7 °C was obtained at an extraordinarily low generating temperature of 83.3 °C. It showed the promising potentials of DAR operating with mixed fluoride refrigerants in applications of low temperature refrigeration and efficient utilization of the low-grade thermal energy.