Potential of Low Temperature Organic Rankine Cycle with Zeotropic Mixtures as Working Fluid

Organic Rankine cycle (ORC) is one of the most technically feasible methods to convert low-grade thermal energy to electricity. Using zeotropic mixtures as working fluid can provide better temperature matches with the heat source and heat sink, so it is regarded as an efficient approach to improve ORC thermodynamic performance. This paper comparatively investigates the performance of low temperature ORC with pure fluids and zeotropic mixtures. We develop a numerical model considering the size of the heat exchangers to predict both the first law thermal efficiency and cost-effective performance. The results indicate that using mixtures does not gain beneficial effect when the prediction program is improved by taking heat transfer model into account.