Characteristic Simulation And Heat Loss Analysis On The Hybrid Heat Pipe Receiver

The extensive use of fossil fuels reduces the energy reserves of the fuels, especially coal and oil, which promotes the rise of the energy price sharply. Meanwhile, the environmental problems resulting from the use of fossil fuels has become increasingly prominent. Considering the severe challenge of the energy and environment situation, it has become the focus of attention around the world to use the renewable energy, such as wind, solar, and biomass for power generation in 21st century. Developing renewable energy is of vital strategic significance for national energy security and environmental improvement.Dish-Stirling solar thermal power system has drawn wide concern at home and abroad because of its high efficiency, modular, adaptable to the environment and other advantages. The solar energy and biomass resources are abundant in China. The development of solar thermal power dish-Stirling system using biomass as a supplement not only can solve the power supply instability of the simple dish-Stirling solar thermal power system, but also can keep in line with the existing policy of sustainable development because the solar energy and biomass are both included in renewable energy.Considering the application characteristics of the dish-Stirling solar thermal power system, a hybrid heat pipe receiver applied in the dish solar thermal power system was proposed, and the theoretic analysis and simulation research were carried out on this receiver in this paper. The major studies and conclusions are summarized as follows:(1)Characteristic and working conditions of the heat pipe was analysed based on the application of heat pipe heat receiver from home and abroad. Elaborate the general and unit constructure, also working principles of the heat pipe. The hybrid heat pipe receiver module was simplified based on heat transfer principles, the basic size and relative position of the receiver was caculated and obtained.(2)The performance of the hybrid heat pipe receiver with different size were simulated and analyzed. Results showed that, the best receivers cavity depth was 200mm, and the optimum orifice diameter was 90mm. A uniform temperature distribution inside the cavity was attained and the utilization of solar energy was high at this condition, and no hot point.(3) The hybrid heat pipe under gas mode was simulated and analyzed. It was found that the power generation efficiency of the solar thermal power system using the heat generated by combustion of biomass was 19%, higher than that of the test value 17%. The optimum thermal insulation thickness of outer wall was 200mm.(4) The simulation analysis on the heat loss with different sizes and different temperatures of hybrid heat pipe receivers was carried out. Results showed that, the receiver cavity depth had little effect on convective heat loss, but it showed a great impact on the radiation heat loss. The convective heat loss and radiation heat transfer loss increased with the increase of orifice diameter. There is a linear relation between the convective heat loss and the heat pipe operating temperature.