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Evaluation of R-1234ze(Z) as drop-in replacement for R-245fa in Organic Rankine Cycles – From thermophysical properties to cycle performance
- Petr, Philipp, Raabe, Gabriele
- Energy 2015 v.93 pp. 266-274
- electricity, global warming, heat, industrial applications, industrial wastes, models, temperature
- To Prof. Jürgen Köhler to his 60th birthday.ORCs (Organic Rankine Cycle) experience growing interest for the generation of electricity from industrial waste heat. However, the widely used working fluid R-245fa does not seem to be sustainable due to its relative high GWP (Global Warming Potential) of almost 900 . In this work, we have evaluated the low GWP working fluid R-1234ze(Z) as drop-in replacement for R-245fa in low-grade ORC processes. Our studies thereby comprise a comparison of the thermophysical properties of R-1234ze(Z) and R-245fa and resulting differences in the performance of the ORC cycle. Information on the thermophysical properties of R-1234ze(Z) from experiment is complemented by molecular simulation results.Our system simulation studies on the ORC process covers a heat source temperature range from 100 °C to 250 °C, which represents relevant operating conditions for industrial applications. A stationary cycle model of a typical ORC configuration was set up in order to optimize operation points and to evaluate characteristic system values for both working fluids.Our simulation results indicate that R-1234ze(Z) is a promising replacement fluid for R-245fa in ORC applications, though noticeable performance losses for heat source temperatures between 183 and 224 °C are observed.