Experimental Investigation on an Intermittent Ammonia Absorption Refrigeration System

Abstract

This project work describes the experimental investigation on an intermittent ammonia absorption refrigeration system which consists of a generator/ absorber, a condenser, an evaporator and an expansion valve. The system used 2.5 kg of ammonia as refrigerant and 1.5 kg of calcium chloride as absorbent initially in generator and this NH3-CaCl2 refrigerant-absorbent pair is widely used to intermittent refrigeration system. There are two modes where in desorption mode, an oil bath arrangement heat source provides heat to the generator and the generator drives of the vapor form refrigerant around the system through a condenser to evaporator. The evaporator pipes were placed outside to the evaporator container which was insulated and 3 kg of water was filled to be the load for cooling into the evaporator container. During the absorption mode, the liquid refrigerant absorbed heat from the surrounding water and performed cooling. The average refrigeration temperature was found to be 13.250C with a minimum value of 11.50C for a period of time up to 2.5 hours absorption. The coefficient of performance was obtained on the average of 0.154 with a maximum value of 0.192. This coefficient of performance was higher than the coefficients of performance found by Vanek [1], atejanekarn [2] and Moreno -Q uintanar [3] on their intermittent solar absorption system and also lower than the COP found by Tangka [4] developed intermittent solar absorption system. The generator temperature was found to be 91 .400C corresponding to the oil bath temperature up to 1100C during 2.5 hours desorption and the pressure was to be found 10.5 bar. On an average the system could provide the heat gained by the generator of 1492.96 kJ and the refrigeration effect of 223.65 kJ.