Organic Rankine Cycles (ORC) represent a sound solution for the exploitation of thermal energy available at low temperature.
The prototype of a small ORC power plant has been realized at the Energy Systems Laboratory of Cassino University.
The basic idea is to analyze the performance of a small ORC plant able to exploit low-temperature heat sources.
The R245fa as working fluid has been selected. Due to the small working fluid flow rates, a volumetric machine, in particular a scroll expander, has been chosen for mechanical power generation.
The hot source temperature has been varied in the range 75 – 95 °C and the cold sink temperature ranged between 20°C and 33°C. The R245fa vapor maximum pressure varied from 6 up to 10 bar. In this operating range, the best obtained results were: electric power equal to 1.2 kW, specific work about 20 kJ/kg and cycle efficiency slightly greater than 9 percent.