Thermal design of components of an ammonia-water absorption chiller

In this study, the thermodynamic analysis of a single stage ammonia - water absorption cooling cycle was performed by using Engineering Equation Solver and thermal loads of the cycle components were calculated. The system has a pre-cooler between the condenser and the evaporator and a solution preheater between the absorber and the generator. In the study, the evaporator temperature is -10 degrees Celsius; absorber and condenser temperature 40 degrees Celsius; solution heat exchanger effectiveness 0.8 and precooler heat exchanger effectiveness 0.5 assumed. According to the calculations, the ammonia concentration rate of the steam leaving the generator and leaving the distillation column is 97.25 percent, and it is enriched in the rectifier at the level of 99.9 percent. The effects of heat exchanger efficiency coefficients and generator temperature changes on the cooling efficiency coefficient and cooling capacity are shown graphically. In the study, the heat capacity of the system components and heat transfer surfaces were calculated and preliminary designs were made for the cooling capacity of approximately 3 kilowatts. Accordingly, the generator heat capacity is 7.798 kilowatt and the heat transfer surface area is 0.65 square meter. Generator and distillation column are designed integrated. The tray diameter of distillation column is 0.05 meter. The amount of heat removed from the rectifier is 0.864 kilowatt and the surface area of the coolant pipe bundle has been calculated as 1.384 square meter. The amount of heat transferred to the cooling water in the absorber is 7.579 kilowatt. The surface area, which is also suitable for mass transfer, is 1.64 square meter.