Optimization of operating temperatures in the gas operated single to triple effect vapour absorption refrigeration cycles

Thermodynamic analysis of LiBr-H2O single, double and triple effect vapour absorption cycles has been carried out using LPG and CNG as sources of energy. Optimization of operating temperatures in single to triple effect cycles has been carried out for maximum COP of the system and minimum gas requirement in it at desired temperatures in evaporator, absorber and main condenser using iterative technique. In single effect cycle, optimum temperatures in main generator have been obtained, while in double effect cycle, low pressure generator, high pressure condenser and main generator temperatures have been optimized. In triple effect cycle having three condensers and three generators, condenser temperatures (Tc3 and Tc4) and generator temperatures (Tg2, Tg3 and Tg) have been optimized. The maximum COP of triple effect cycle goes up to 1.955 which is around 132% higher than single effect cycle with its gas requirement reduced to around 122% at the same conditions.