Exergo-economic evaluation of an organic Rankine cycle with a solar thermal source for industrial applications

The efficiency of the organic Rankine cycle (ORC) assisted with solar thermal energy is 0.13 and varies significantly with the temperature of the solar thermal source, modifying the energy cost from 0.1089 USD/kWh to 0.1392 USD/kWh. In this work, the exergy destruction of the cycle and by equipment is evaluated when the source temperature varies, and the impact on the energy cost is determined. Industrial processing of sesame seeds was selected. The temperature of the solar thermal source was varied in the range of 60–99 °C and the temperature difference between the source and the sink in the evaporator was 6 to 12 °C. The maximum energetic and exergy efficiency of the ORC is obtained with the R1234ze(Z) with 99 °C at the source and a temperature gradient of 6 °C. The energy efficiency is 9.67% and the exergy efficiency is 48.65% of the ORC. The cost of the generated energy is 0.103 USD/kWh, 30% lower than that reported for fossil fuels of 0.148 USD/kWh. Quantifying exergy destruction and eliminating or minimizing losses, reduce the energy cost.