Comparative efficiency assessment of a novel low-temperature solar-powered ORC based cogeneration system

A novel cogeneration system driven by low-temperature solar heat sources was investigated. The system consisted of a low-temperature solar-powered organic Rankine cycle (ORC) subsystem and an ejector refrigeration subsystem. The injector of this system is driven by the exhaust of the expander, so that the cogeneration system can produce both power and refrigeration simultaneously. Four definitions of efficiency were provided in the present paper in order to assess the system performance. R600a was chosen as working fluid. A simulation model was established to evaluate the influences of generating temperature, condensing temperature, evaporating temperature, expansion ratio of expander and solar radiation intensity on the system performance. Results indicated that enhancing the generating temperature, as well as enhancing evaporating temperature and/or lowering the condensing temperature can increase the injector's inject coefficient, consequently improve the system's thermodynamic efficiency and thermodynamic conversion efficiency. Therefore, the performance of the entire system can be strengthened. The electricity-cold ratio of the system can be adjusted by the expansion ratio of expander changing. (author)