Thermodynamic optimization of hybrid solar-geothermal power plant coupled with DCMD for water and electricity production: A Case study at Ain Khulab, Saudi Arabia

Abstract

A potential solution for tackling the water and energy constraints in remote areas is through the hybridization of the solar-geothermal power plant. The integration of solar and geothermal energy is a promising technology and can be used to preheat the working fluid in Organic Rankine Cycle (ORC). In this study, integration of an ORC with solar-geothermal energy and direct contact membrane distillation (DCMD) is posed, with an end goal of minimizing the Levelized cost of energy (LCOE) and post-water productivity. A mathematical model was built and verified to examine the operation of the proposed system based on actual environmental conditions. The developed model is simulated in the MATLAB. The system's performance was optimized across a wide range of operating conditions through genetic algorithms. The optimal results were obtained based on the working fluid used in the ORC, the evaporative and condenser temperature, the area of the solar collectors, and the mass flow rate to the DCMD. Two working fluids, R113 and R123, were used to determine their impact on the system's performance. Results show that annual water productivity can reach 2837 m3 while the yearly power generation is around 480 MW when R123 is used as a working fluid. The best levelized cost of energy (LCOE) was 0.136 $/kWh when R123 was employed as the working fluid. This study offers valuable insights to enhance the design and optimization of similar integrated systems and contributes to the advancement of sustainable energy technologies.

Keywords

• Solar energy
• Geothermal energy
• Membrane distillation
• Organic rankine cycle