Studies of compressor pressure ratio effect on GAXAC (generator–absorber–exchange absorption compression) cooler

This paper presents simulation studies conducted on a GAXAC cycle of capacity 3.514 kW using ammonia–water as working fluid for cooling applications. The low side pressure ratio of (compressor pressure ratio) of the cycle has been optimized for optimum COP. The effects of temperatures of the generator, condenser, absorber and evaporator on the COP of the cycle as a function of low side pressure ratio have been studied. The effect of the low side pressure ratio on the heat duties (kW) of the cycle has also been studied. It is found that for a given value of desorber and approach temperatures, the optimum COP corresponding to the optimum pressure ratio is independent of the temperatures of condenser, absorber and evaporator. The optimum COP for the desorber temperatures 110 °C, 130 °C, 150 °C and approach temperature 14 °C at all optimum pressure ratios are found to be 1.00, 0.97 and 0.94, respectively. Comparison of GAXAC and standard GAX cycle was carried out and found that GAXAC cycle has 26% higher value of COP than the standard GAX cycle.