Experimental studies on the performance of bubble pumps for the R134a-DMF diffusion absorption refrigerator

摘要

An experimental setup has been built to test the performance of the bubble pump operating with R134a-DMF (N, N-dimethylformamide) for the diffusion absorption refrigerator. Bubble pumps with three inner diameters of 6mm, 8mm and 12mm of the lift tube were tested with three R134a mass fractions of 12.5%, 15% and 17.5%. The experimental results showed that: (1) At the same concentration of R134a, the gas mass flow rates all increased approximately linearly with the increased of the heat input for three bubble pumps, and the start-up heat inputs of the bubble pumps increased with the following order of the lift tube inner diameters: 6mm, 8mm and 12mm; (2)At the same concentration of R134a, pumping ratios decreased obviously with the gas mass flow rate, and also decreased obviously at the specified gas mass flow rate with the following order of the lift tube inner diameters: 8mm, 12mm and 6mm, while the influence of concentrations of R134a on the pumping ratios were not obvious; (3) At the same concentration of R134a, generation temperatures increased approximately linearly with the heat input for three bubble pumps, while the system pressures varied only a little. The influences of R134a concentrations on the generation temperatures were not obvious, but those on the system pressures were great. The experimental results obtained in this study can provide important references for the optimization design of the diffusion absorption refrigerator.