Hybrid solar-geothermal power generation: Optimal retrofitting

A model is developed for an existing organic Rankine cycle (ORC) utilizing a low-temperature geothermal brine including the performance characteristics of the components. The model is validated with a set of 7200 operation data collected in one-year. The operation of the ORC is optimized allowing for variable number of working turbines. The developed model is retrofitted with a low-temperature solar trough system. A new hybridization strategy is developed that achieves a significant boost in the net output power of the system compared to the geothermal ORC. This hybridization approach enables better extraction of geothermal energy. The hybrid system shows higher second-law efficiency (up to 3.4% difference) compared to combined individual geothermal and solar systems. With this hybridization approach, the hybrid system is a better option than individual geothermal and solar system at all ambient temperatures. (C) 2014 Elsevier Ltd. All rights reserved.