A critical review of power generation using geothermal-driven organic Rankine cycle

Organic Rankine Cycle (ORC) is a promising electricity production technology that exploits low and medium heat sources. Usually, renewable and alternative heat sources can be used in order to feed an ORC with heat. The exploitation of geothermal energy is a usual and sustainable way to feed an ORC because it is a sustainable, abundant, economical and environmentally friendly choice. The main objective of this study is to review and to discuss the geothermal-driven ORC systems for power generation in a detailed way. Moreover, the special novelty is the emphasis that is given in the use of geothermal ORC systems inside cogeneration, trigeneration and polygeneration units. Both experimental and numerical investigations are included in the present work, while they are discussed in energy, exergy and economic terms. It is found that the geothermal-driven ORC systems are viable investments with relatively low payback periods, as well as these systems lead to high energy efficiency. Moreover, it is concluded that a 20% to 30% increase in the performance of geothermal-fed ORC systems is possible by optimization. Lastly, it is useful to state that the polygeneration systems that include geothermaldriven ORCs are promising units that present high exergy efficiency values.