Experimental research on the performance of a gas lift bubble pump based on a diffusion generation process

The refrigerant generating bubble pump, in which the generation of refrigerant vapor and the pumping of solution both take place, is used to transport refrigerant, absorbent and diffusion gas in a diffusion absorption heat transformer. In this paper, experiments of refrigerant generating bubble pump were performed with H2O (water) as refrigerant, HCOOK (potassium formate) as absorbent and air as diffusion gas. The influences of motive head, inner diameter of lifting tube, generating temperature and diffusion gas flow rate on the refrigerant generating and solution pumping performance were investigated. Increasing motive head or inner diameter of lifting tube led to the decrease of solution flow rate and pumping ratio. While the diffusion gas flow rate increased, the solution flow rate and pumping ratio decreased, and the refrigerant flow rate increased under most conditions. It was observed that the refrigerant flow rate was the largest when the inner diameter was 9 mm and the generating temperature was 95 degrees C. These results will facilitate the design and development of diffusion absorption heat transformers in the future.