- The performance of a diffusion absorption refrigeration system is dependig primarily on the performance of the bubble pump. The bubble pump is a vertical tube with a heating element at the botton, in which a flow is induced by a boiling and segregation process of a binary solution. The supplied heat, generated gas that lift up the binary mixture through the verticaltube in various two-phase modesof flow. In the present study, the performance of a bubblepump with organic working fluids was carried out experimentally. During the investigation pictures were taken showing that the bubble pump operates at slug flow regime with a churn floow regime at the entrance of the bubble pump tube and that performance of the bubble pump depends mainly on the motive head and on the heat input to the bubble pump.