Experimental and numerical analysis of variable volume ratio as additional optimization parameter in organic Rankine cycle expanders

In this paper, the use of a variable volume ratio expander for 10 kWe organic Rankine cycle (ORC) to be integrated in Carnot battery has been studied. The reciprocating piston used work built-in mechanism which allows changing inlet valve timing and hence internal - pressure ratio. experimental results ORC prototype are presented. A total 58 steady state points collected by varying heat source cold sink temperature, refrigerant mass flow rate, speed timing. presented terms electrical power output efficiency isentropic volumetric efficiencies determined different timings. Although clearly show effect on performance we here present combined experimental-numerical approach is necessary evaluate under external conditions. Therefore, an empirical quasi-steady model calibrated based results. Subsequently, numerical analysis, various timings evaluated time-varying boundary maximal difference 14.2 % net production observed between most optimal least However, study only increased maximally 1 compared fixed Altogether, demonstrates benefit expanders ORCs