Thermoeconomic analysis and off-design performance of an organic Rankine cycle powered by medium-temperature heat sources

The results of the off-design analysis show that the heat source mass flow rate is a key parameter in net power generation. Fixed the heat source temperature on the upper bound of its variation range (185 °C), the net power generation shows both the maximum and minimum value, 335.4 kW and 269.3 kW, in correspondence of the lowest and the highest value of heat source mass flow rate respectively. Moreover, the results show that the plant efficiency decreases as both heat source mass flow rate and temperature increase. Its maximum value, 14.7%, is achieved for heat source temperature and mass flow rate equal to 155 °C and 18 kg/s, while its minimum value, 9.54%, is reached for heat source temperature and mass flow rate equal to 185 °C and 24 kg/s.