The process parameters of ammonia-water absorption system were optimized in terms of temperatures of generator and condenser and heat ratios of generator-to-condenser and generator-to-absorber. The iteration method was used to get the variation in generator and condenser temperatures with coefficient of performance (COP) for the fixed evaporator temperature. The sizing of generator, absorber and condenser was found from the variation of heat ratios of generator-to-condenser and generator-to-absorber for the fixed evaporator cooling load. The result showed that the optimum generator and condenser temperatures were achieved at 88 and 32 °C, respectively for the maximum coefficient of performance (COP) of 0.68. The simple rule of thumb was evolved for the sizing of condenser and absorber and found to be 1.2 times of generator size in terms of heat value. Keywords: Aqua-ammonia, vapor-absorption refrigeration, optimization, COP
