Optimal Organic Working Fluid for the Rankine Cycle Operating by Parabolic Trough Solar Collector

Abstract This paper investigates finding the best working fluid to improve the giving of the solar organic Rankine cycle. A parabolic trough solar complex was designed to focus the sun rays on a vicious cylinder to produce sufficient steam to operate the ORC. The steam is collected in an isolated tank filled with molten salt called an evaporator. The heat gained in this evaporator is transferred to feed the power generation turbine. Ten different working fluids of R123, R143a, R433A, R290, R40, R22, R600a, R601, RC318 and R1270 were tested at a boiling temperature from 150°C to 240°C. The results showed that using R601 as a working fluid for ORC gave the highest thermal efficiency compared to other organic liquids tested at temperatures from 150 to 240 °C. R601 gives a gain in cycle thermal efficiency by about 24.6% relative using R600a. While R 290 gave an improvement in the power produced by the turbine estimated at 10% higher than that used at higher temperatures above 240° C.