EXPERIMENTAL INVESTIGATION OF THE PARTIALLY EVAPORATED ORGANIC RANKINE CYCLE FOR VARIOUS HEAT SOURCE CONDITIONS

The Organic Rankine Cycle (ORC) could potentially play a vital role in the mitigation of climate change due to its ability to enable low-temperature heat sources for power generation. Next to the ORC, the partial evaporated Organic Rankine Cycle (PEORC) has recently received increased attention in the literature. In contrast to the ORC, the working fluid is not fully evaporated in the PEORC, which allows a higher utilization of the heat source due to a better match of the temperature profiles of heat source and working fluid during heat transfer. In this paper, both concepts are experimentally compared by their ability to generate net power outputs from a variety of different heat source conditions. Therefore, the heat source temperature is varied between 110 °C and 140 °C and the heat source mass flow is varied between 250 g/s and 400 g/s at a test rig. For all investigated heat source conditions, the optimal operating parameters, which provide the highest net system efficiencies, were identified. The results show that the PEORC outperforms the ORC for all investigated heat source conditions in terms of net system efficiency, especially at low heat source temperatures. While the thermal efficiency is higher in case of the ORC concept, the considerably higher heat transfer efficiency of the PEORC overcompensates the lower thermal efficiency.