Heat and Mass Transfer-Enhancement Technique Used for Vapour Absorption Refrigeration System

The vapour absorption refrigeration system (VARS) as a future cooling–heating system to meet the energy crises and to replace the mechanical vapour compression systems (VCR) also utilized the waste and renewable energy. The different renewable energy sources uses as the driving source for the VARS are waste energy from the industrial exhaust heat or solar thermal energy to efficiently run, meet the cooling load capacity, and have lesser impact on the climate and the environment. Nowadays, the cost of electric power raising high and the change in climate require the system for more efficient design to make the system more compatible size which guides to save energy. Absorber is a vital component for a VARS, heat and mass transfer (HMT) analysis concern. Better design of absorber impacts on the absorption process, coefficient of performance (COP) of the VARS which reduces the shape and size absorber and generator sizes. The objective of this paper is to identify various enhancement techniques used for heat and mass transfer like absorber and generator and summarize the system performance, on experimental and numerical studies. The enhancement techniques are classified into passive and active methods; twisted tape, swirl generator, axial guide vane, internal grooved, internal and external fins, rotation of tube are the geometrical device used as a passive methods, and use of additives, nano-fluids, induced pulsation by cams, reciprocating plungers, vibrators, use of magnetic fields, etc., are the passive technique. Finally, the present literature database contains suggestions for future work for the absorber and generator for enhancement in the HMT in absorbers and performance of the VARS.