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Experimental study of an ORC (Organic Rankine Cycle) and analysis of R1233zd-E as a drop-in replacement for R245fa for low temperature heat utilization

Eyerer, Sebastian, Wieland, Christoph, Vandersickel, Annelies, Spliethoff, Hartmut
Energy 2016 v.103 pp. 660-671
electric power, global warming potential, heat, mass flow, ozone depletion, temperature
The Organic Rankine Cycle can be applied to convert low temperature heat to electrical power using organic working fluids. Recently, a new generation of working fluids has been introduced with almost no Ozone Depletion Potential and significantly smaller Global Warming Potential, compared to currently used refrigerants. R1233zd-E is a promising low-GWP (global warming potential) alternative to R245fa, a widely used fluid in ORC (Organic Rankine Cycle) systems. This paper analyzes the applicability of the new fluid as drop-in replacement for R245fa in existing systems and compares system parameters such as cycle efficiency and power output. To this end, the influence of the process parameters mass-flow rate, condensation temperature and expander rotational speed is investigated experimentally for both fluids. The test rig used has an electrical heater as a heat source and a scroll compressor as an expander. As a conclusion, R1233zd-E can be used as a substitute for R245fa in existing ORC systems. In addition to the advantage of having a much smaller GWP, the use of R1233zd-E may lead to higher thermal efficiencies. Comparing the highest achieved thermal efficiency, R1233zd-E performs 6.92% better than R245fa. However, comparing the maximal gross power output, R245fa performs 12.17% better than R1233zd-E.