Thermodynamic Properties of ORC System with Zeotropic Mixed Working Fluids for Low Temperature Waste Heat Recovery

摘要

Organic Rankin Cycle (ORC) is an effective technology to transform low-grade energy resource into electricity. In this paper, based on thermodynamic principle, considering the waste heat resource lower than 120℃, thermodynamic properties of ORC with working fluids of R245fa, mixed R21/R245fa and mixed R152a/R245fa were assessed. The results show that high evaporation temperature contributes to improved system performance. The . Rankine Cycle that uses R21/R245fa can increase net cycle output, thermal efficiency and exergy efficiency by 3.02%, 2.35%, and 4.44%,respectively, as compared to that with pure R245fa. When using R152a/R245fa as working fluid, the net cycle output can increase by 3.83% at most, while the thermal efficiency decreases by 8.7%. These results indicate that R21/R245fa has a good advantage in improving the cycle thermodynamic performance.