Performance Analysis of an Organic Rankine Cycle for Integration in a Carnot Battery

orc2019 Tracking Number 171

The purpose of this study is to report the challenges associated with the design of an ORC setup to be connected to a power-heat-power system, also known as a Carnot battery. Power is converted to heat using a high-temperature heat pump (HT-HP) and is stored using a separate sensible and latent heat storage system, consisting respectively of a phase change material (PCM) i.e., molten salt and pressurized hot water. Simulations are carried out in Python and Engineering Equation Solver (EES) to investigate the effect of the two storage systems on the performance of the ORC considering different working fluids. Working fluids that have low global warming potential (GWP) and zero ozone depleting potential (ODP) are considered. Minimizing irreversibilities during pre-heating and evaporating is of key importance. The identified working fluids of interest are HFO-1336mzz(E) & R1234ze(Z). The exergy destruction in the ORC increases by 73 % if R1234ze(Z) is used as the working fluid. Finally, based on the acquired results, a preliminary test-rig is developed with a volumetric piston expander. The net power output from the test-rig is estimated to be approximately 10 kWe.