Thermodynamic, economic and environmental assessment of a novel organic Rankine cycle-vapor compression refrigeration system using zeotropic mixture

The improvement of system configuration is an effective method to improve performance of the organic Rankine cycle-vapor compression refrigeration (ORC-VCR) system. A novel system with a recuperator on the ORC side and a flash tank on the VCR side is proposed. Firstly, the theoretical model of thermodynamic, economic and environmental performance is constructed. Then, the novel system is compared with the basic ORC-VCR system. Next, the effects of operating parameters on performance of the proposed system are investigated. Finally, a comparison of system performance in different positions of phase transition temperature is carried out. The results show that the coefficient of performance(COP), exergy efficiency, dynamic payback period(DPP), net present value(NPV) and annual emission reduction(AER) of the novel system are 0.38, 5.94 %, 8.89 years, 1.52 x 106 $ and 5.77 x 106 kg, respectively. Compared with the basic ORC-VCR system, the improvement in thermodynamic performance of the novel system is relatively preferable to the deterioration in economic performance. Moreover, the effect of mixture composition on system performance is distinct in different positions of phase transition temperature. It is shown that using zeotropic mixture is not appropriate in all cases. This paper can provide theoretical guidance to further improve performance of the ORC-VCR system.