A review of organic Rankine cycles with partial evaporation and dual-phase expansion

Organic Rankine Cycle (ORC) is a power cycle for the exploitation of low-grade energy sources like solar irradiation, geothermal energy, waste heat streams, etc. Different ORC designs have been suggested in the literature aiming to enhance the system’s performance and maximize electricity production. The present review study aims to present and discuss in detail the use of partial evaporation and the dual-phase expansion in the ORC for maximizing the exploitation of the energy source. Usually, the waste heat sources are ideal candidates for the application of the studied idea, while also there are designs with solar thermal sources that use partial-evaporation designs. The working fluid selection, the optimal vapor quality in the expander inlet, the expander selection and other issues are presented and discussed in this work. The analysis of the literature reported results indicates that the system efficiency ranges from 3% up to 16%, while the respective thermodynamic efficiency takes a bit higher value which reaches up to 17.5%. The conclusions of the present review can be exploited for the further development of the ORC with partial evaporation aiming at the sustainability of this technology.