Numerical investigation of absorption diffusion water ammonia refrigerator

A diffusion absorption refrigerator is a heat (sun heat) powered refrigeration system. It can be operated without any use of electrical or mechanical energy. It has no moving parts. The working fluid is a three component mixture: ammonia as refrigerant, water as absorbent and helium as inert gas used to equalize the total pressure in the evaporator-absorber compartment. In the present work a model of each element in this machine is developed. The considered machine is intended to be used for air conditioning applications. The design cooling capacity of the investigated machine is 2 kW and the evaporator exit temperature is minus -5°C. The simulation model leads to results in fair agreement with the experimental data. The major performance determining operational parameters of the machine are: the generator temperature, the bubble pump exit void fraction, the evaporation mean temperature and the cooling medium mean temperature.