Performance investigation on Organic Rankine Cycle from a low-temperature heat source

Waste heat is available in ample quantities from resources, such as industrial waste heat, geothermal energy, furnaces, boilers, solar thermal systems, and process plants. The quality potential for this waste heat seems to be small, but quantitative, and its impact is large. The application of the Organic Rankine Cycle (ORC) in the existing test rig improves the net power output and, consequently, the overall performance of the test rig. The purpose of this study is to implement an ORC system to harness waste heat from an artificial heat source. A running ORC test rig was fabricated economically for the rated DC motor power output capacity. The system is supplied with a heat transfer fluid, which transfers heat to R245fa. Temperature varied in the evaporator in the range of 110 °C–155 °C, and accordingly, all the operating parameters, such as turbine work, network, energy and exergy efficiencies, total exergy destruction, and relative efficiency, were assessed. The results show that the energy efficiency and exergy efficiency increased from 4.6 % to 10.5 % and 2.4 %–5.6 %, respectively, for the above-specified evaporator range. This model is expected to be applicable and scalable for tapping waste heat from low-grade heat sources.