Exergy Analysis Of Energy Transformation Process For The Energy Storage System Combined Cooling And Heating

A closed variable mass energy transformation and storage (VMETS) system for air-conditioning and heating using aqueous lithium bromide as working fluid is studied in this paper. Based on the second thermodynamic law, the exergy analysis of energy charging and discharging process of the energy storage system using aqueous lithium bromide as working fluid for air-conditioning and hot water supplying is analyzed and researched.First the advanced VMETS system working principle is described and then the exergy balance models of the energy storage system working process are established. Based on these exergy balance models, the operation characteristics of the system according to a specific example are simulated by numerical simulation respectively under the full and partial storage strategies. The changing rules like the exergy stored in the tanks, the exergy loss of each heat-exchange equipment, the exergy efficiency of the system, and so on are obtained by simulation under the full and partial storage strategies. The research results can point out the way to reduce the exergy loss of the equipment and improve the exergy efficiency of system during the energy transformation process.According to the study , under the full and partial storage strategies the changing rules like the exergy stored in the tanks, the exergy loss of each heat-exchange equipment are primarily consistent, and the difference between the exergy efficiency of the system are small. The total exergy loss of the system is largely occupied by the exergy loss of the generator/condenser and the compressor, in order to improve the exergy efficiency of the system, the exergy loss of the generator/condenser and compressor should be reduced.