A brief research on four different solar thermal power generation systems based on Stirling engine

Abstract

Stirling engine is an external gas turbine. Its requirements on working medium pressure and manufacturing materials make it rarely used in civil industry, but its high thermal efficiency, low noise and small footprint make Stirling engine widely used in military industry. For example, as a engine powered by out-sourced heat, it is usually used in the nuclear submarine. This research mainly focused on the using of Stirling engine in solar-thermal power generation system. The system uses a series of optical devices to focus solar energy into the engine's hot chamber, where it is converted into heat for generating electricity. Because the system can use thermal storage technology, molten salt is used to store the heat of sunny days to achieve a smooth power output when the sun is not providing enough heat. In this article, we discussed the difference between different types of solar-thermal power generation system, do research and preliminary experiments to compare their efficiency and abilities. The main research of this paper is solar Stirling engine. Firstly, we research four different types of solar-thermal power generation system: central receiver, parabolic through，Dish-Stirling and the Fresnel type. Secondly, we do some preliminary experiments in order to compare the power between the Dish-Stirling system and the Fresnel system. But, because of the bad weather we decide to replace the sunshine by candles. Finally, we do the conclusion of the whole research. In this study, ANSYS Fluent 14. 5 software was used to conduct numerical research on the β Stirling engine model without regenerator, and it was found that the performance was best when H2 gas was used as working medium. The Stirling engine was replaced by a non-ideal adiabatic method. In this study, non-ideal adiabatic analysis and the second edition of non-dominant sequencing genetic algorithm were used to optimize the efficiency and power loss of Sterling system heat exchanger. The α Stirling engine was chosen for cost reasons, as many parts from industrial mass production can be used. Necessary repairs to Stirling engines can be done by standard garages. The engine used an electric furnace as a heat source, and was tested with air and helium. The operating characteristics of the engine in the range of heat source temperature 700-1000°C and charging pressure 1-4. 5bar are analyzed. Hium achieves maximum power output at 1000°C heat source temperature and 4 bar charging pressure 128. 3W.