Experimental study of an Organic Rankine Cycle with HFO-1336mzz-Z as a low global warming potential working fluid for micro-scale low temperature applications

An experimental evaluation of HFO-1336mzz-Z as a low global warming potential working fluid for ORC systems in micro-scale low temperature applications has been conducted. The energy performance in a fully monitored ORC module has been analyzed varying the heat source temperatures between 140 °C and 160 °C and heat sink temperatures between 25 °C and 40 °C. The ORC module uses a regenerative configuration allowing heat recovery not only from the heat source but also from the expanded vapor, thus improving the cycle thermal and electrical efficiency. The maximum gross electrical power generated was 1100 W, while the net electrical efficiency ranged from 5.5% to 8.3%. The volumetric expander performance was analyzed by means of the filling factor, while deviations of expander operation from ideal performance were evaluated by means of the isentropic and overall expander-generator efficiency. Net electrical efficiency, isentropic expander efficiency and volumetric expander performance obtained with HFO-1336mzz-Z in this work are higher than those obtained with HFC-245fa in a previous work using the same experimental facility.