A geothermal energy driven integrated energy system for fresh water and power production

Abstract

Geothermal energy can play a crucial role in the global energy transition towards more sustainable and renewable sources. It can contribute in numerous ways including renewable and clean energy, baseload power generation, energy independence and security, heating and cooling applications, economic benefits and transition support for fossil fuel-dependent regions. Considering the modest deployment of geothermal energy regardless of its immense potential, this study explores the better utilization of geothermal energy for multigeneration purposes that also improves the system efficiencies. In this study, a binary-type geothermal-based system is developed for multigeneration including power generation, seawater desalination and hot water production. The system incorporates an isobutane entailing organic Rankine cycle (ORC) to generate electrical power and a flash distillation system for seawater desalination. A detailed thermodynamic analysis including first and second law efficiency assessment is performed to depict the performance of the designed concept. The system entails a power output of 2262 kW and seawater desalination rate of 11.09 kg/s. The energy efficiency of the overall system is evaluated to be 23.5 %. Also, the exergy efficiency is found to be 28.9 %. In addition, the ORC energetic efficiency is determined to be 7.9 % and the exergetic efficiency is evaluated as 51.1 %. Moreover, the flash distillation subsystem has energetic and exergetic efficiencies of 9.3 % and 2.7 % respectively. Several parametric studies are performed to investigate the effects of varying system conditions and operating parameters on system efficiencies.