Energy generation and storing electrical energy in an energy hybrid system consisting of solar thermal collector, Stirling engine and thermoelectric generator

Abstract

• A new energy system for energy production and storing based LFR, Stirling engine, and thermoelectric generator is investigated; • Two different scenarios are considered for the generated energy, i.e. produce hydrogen fuel by an alkaline electrolyzer, and energy is stored by a storage system; • the proposed system can produce 11.73 kWh of electrical energy with an overall efficiency of about 43.6%; • About 100.8 moles of hydrogen fuel can be produced during the working hours of the energy system. Energy researchers believe that by storing energy the frequency and voltage of renewable energy systems can be better controlled and increases the use of renewable electricity by providing sustainable energy. Hence, the use of renewable solar energy coupled with an energy storage technology can be fruitful for urban areas in achieving sustainable development and reducing environmental crises. This study presents and investigates a new energy system for energy production and storing. The energy generation unit is a Linear Fresnel Reflector (LFR)-based hybrid system coupled to a Stirling engine and a thermoelectric generator. Two different scenarios are considered for the generated energy: 1) the available electrical energy is consumed to produce hydrogen fuel by an alkaline electrolyzer, and 2) the available electrical energy is stored by a storage system. Solar energy is converted into thermal energy by LFRs. Thermal energy then enters the Stirling engine and according to the Stirling cycle, thermal energy is converted into electrical energy. To prevent heat loss of the engine, a thermoelectric generator is thermally coupled to the engine to generate electrical energy. Results indicate that the proposed system can produce 11.73 kWh of electrical energy with an overall efficiency of about 43.6%. In addition, the solar system embedded in the cycle must be able to produce 2.96 kW of thermal energy per hour. To store generated electrical energy, the storage system should be about 7.8 m 3 in size. Furthermore, 100.8 moles of hydrogen fuel can be produced during the working hours of the energy system. Finally, a comparison is made between the performance of the PTC and the LFR in supplying the heat required by the Stirling engine.