Investigation on the optimum working fluid for organic Rankine cycle with small temperature difference

Abstract

Low grade thermal energy, such as waste heat from industry and renewable energy is abundant source. Organic Rankine cycles (ORC) is a measure to recover electricity from low grade thermal energy. In this study, an ORC 50°C level heat source was investigated by thermodynamic cycle analysis that is driven by sources. A cycle performance under given temperature condition was computationally obtained by Engineering equation solver (EES). 69 working fluids were calculated in EES, and compared in terms of net thermal efficiency. It was fluid that refrigerant R407C achieved the highest net thermal efficiency because its zeotropic characteristic.