EXPERIMENTAL INVESTIGATION OF THE BUBBLE PUMP OF A SINGLE PRESSURE ABSORPTION REFRIGERATION SYSTEM UNDER THE EFFECT OF PRESSURE AND AMMONIA CONCENTRATION

Bubble pump plays a crucial role in single pressure absorption refrigerators as it drives the systems. Its performance is influenced by parameters such as the tube diameter, pressure, and ammonia concentration. In this study, the flow and performance under the effect of pressure and ammonia concentration were investigated. The increase in ammonia concentration leads to an increase in the size of bubbles and the mass flow rate. The heater temperature is independent of the tube diameter but is influenced by the system pressure and ammonia concentration. The bubble pump performance reduces the decrease in the ammonia concentration and contributes to the increase in the pressure or tube diameter. The timing equations of Chan and McCulloch were verified under various system conditions and dimensions. The average estimation error for the water-based 1-4 bar bubble pump is 12.8%. Meanwhile, the average estimation errors for the ammonia solution bubble pump with 6.5-9.6 mm tube diameter, and with 0.0-0.3 (mass fraction) ammonia concentration are 17.9% and 18.8%, respectively.