Experiments on the performance of bubble pumps with R134a/R23-DMF solutions for diffusion absorption refrigerator

•Pumping performance of bubble pump with three independent variables was tested.•Pumping performance of bubble pump with 8 mm and 10 mm lifting tubes were similar.•Pumping performance was barely affected by concentrations of R134a/R23 solutions.•Pumping performance decreased with the decrease of head.•The bubble pump with 10 mm lifting tube had wider operation ranges of pumping ratio. Experiments on the performance of a bubble pump for diffusion absorption refrigerator with different lifting tubes (diameter of 8 mm and 10 mm), different filling compositions of R134a/R23 (35%/0%, 33.5%/4%, 32.2%/8%, and 30.8%/12%) and different heads (0.51 m, 0.54 m, 0.57 m, 0.6 m and 0.63 m) were conducted. The range of heat input was 233–1080 W. The experimental results revealed that: (1) larger heat input and lower head resulted in not only larger gas mass flow rate, but also higher generating temperature; (2) larger gas mass flow rate and lower head led to smaller pumping ratio; (3) the system pressure increased with mass fraction of R23; (4) at the same R134a/R23 mass fraction and head, the operation ranges of the 10 mm lifting tube were wider than those for the 8 mm lifting tube considering of pumping ratio, poor solution mass flow rate and gas mass flow rate. These results will be helpful to the design of bubble pumps for diffusion absorption refrigerators working with binary refrigerants.