A combined energy system for generating electrical and thermal energies using concentrating Solar System, fuel cell and organic Rankine cycle; energy and exergy assessment

Abstract

ABSTRACT Relying on solar-based hybrid energy systems can reduce many of the challenges of fossil fuels and environmental crises. The purpose of this paper is to introduce and evaluate a concentrating solar technology based-energy system for the production of electricity, thermal energy and hydrogen fuel. In this regard, parabolic trough collectors are used to generate thermal energy using solar energy. Organic Rankine cycle, which receives thermal energy from the solar field, generates electrical energy during a Rankine cycle and using an organic fluid. A fraction of the electrical energy produced by organic cycle is consumed by an electrolyzer and hydrogen is generated by the decomposition of water. Due to the fuel cell’s capabilities and advantages, the products obtained from the water electrolysis process are then injected into proton exchange membrane fuel cell to generate power and heat from the chemical energy of the fuel. In addition, a thermoelectric generator is coupled to the fuel cell, which uses the heat released by the fuel cell’s exhaust to generate additional electricity. Since the main source of power generation is based on solar energy, therefore energy production based on the introduced energy cycle can be considered a green approach. In addition, the relationships between the components in the energy system are new and do not correspond to the reported similar literature. The results show that the system can generates 147.8 kWh/day of electrical energy and 595 g/day of hydrogen fuel. Furthermore, the system has an efficiency of approximately 36%. The required areas of the fuel cell and electrolyzer were 0.35 m2 and 0.42 m2, respectively. Solar field and thermoelectric generator destroy the most and the least system exergy.