Enhanced exergy analysis of a bubble-pump-driven LiCl-H2O absorption air-conditioning system

A thermally-driven bubble pump can replace the electrical pump in the absorption refrigeration cycle for lifting solution from the absorber to the generator and producing the required refrigerant vapour for the cooling effect. However, the lower efficiency of bubble-pump-driven absorption refrigeration cycle hinders its widespread application. The potential of a bubble-pump-driven LiCl-H2O absorption refrigeration system that can be powered by solar thermal energy or waste heat energy is discussed and analysed in this study. The new concept of enhanced exergy analysis is integrated in the thermodynamic analyses, which quantifies the available exergy destruction of each component for overall system performance improvement. The analyses uncovered that 80% of the total exergy loss is due to each component's own internal irreversibilities, whereas the remaining is through the interaction of the irreversibilities of other components in the system. The analyses revealed that though the highest exergy losses (46%) are in the absorber, priority for improvement should be given to the generator. Furthermore, the exergy losses of the condenser, the evaporator, and the solution heat exchanger are mostly unavoidable and can be reduced by improving the other components of the system.