Thermodynamic and thermo-economic analysis of integrated organic rankine cycle for waste heat recovery from vapor compression refrigeration cycle

Abstract

In the present study, an integrated air-conditioning-organic Rankine cycle (i-AC-ORC) system which combines a vapour compression cycle and an organic Rankine cycle is proposed. An organic Rankine cycle system is applied to recover the waste heat rejected by the condenser of air-conditioning system. The selection of optimal fluid pairfor the air-conditioning subsystem and organic Rankine cycle subsystem is investigated. Based on thermodynamic (energy and exergy) and thermo-economic analysis, R600a-R123 is chosen as the fluid pair for this integrated air-conditioning-organic Rankine cycle system. The thermodynamic model has been programmed using Engineering Equation Solver (EES). The combined coefficient of performance (COP) of integrated system can be improved from 3.10 to 3.54 compared with that of the standalone air-conditioning subsystem. The organic Rankine cycle subsystem can yield1.41 kW of net electricity with a thermal efficiency of 3.05%. The organic Rankine cycle subsystem operates with an exergy efficiency of 39.30%. In addition, energetic and exergetic performances of the integrated system are studied with variable external conditions.