Research On Dish Splicing Concentrating System For Solar Thermal Power Generation

With the growth of economy and social development,the problem of energy consumption has become increasingly prominent,and solar energy as a clean and sustainable energy source is widely used.Among them,solar thermal power generation systems have attracted attention because of their excellent power generation efficiency.However,in the dish solar thermal power generation system,there are problems such as difficult mirror processing and high tracking accuracy requirements,so that it can not be large-scale commercial production,in view of these problems,a dish splicing concentrating system for solar thermal power generation is proposed,which provides a solution for the large-scale production of dish solar concentrators.According to the edge angle theory,the optical models of regular hexagon,square and circular disc concentrators with different opening shapes were established,and the model was divided into two groups by the size of focal length and edge angle,and the second group of models with the same size of receiving area and edge angle were traced by ray,and the geometric concentration ratio factor was defined,and it was concluded that the regular hexagonal opening has better performance than the square opening under the condition that the receiving area and edge angle size are consistent.A disc splicing concentrator with a single planar mirror as a regular hexagon was established,and the geometric condensation ratio factor of the spliced concentrator increased with the increase of the number of layers and the total number of mirrors.The five-layer,single mirror side length of 0.85 m spliced concentrator is simulated and the system performance is analyzed,and it is found that the energy flow density of the focal plane of the spliced concentrator is smoother than that of the circular disc concentrator,which can meet the requirements of thermal power generation.The power of the whole system is 25 kw,the thermal efficiency of the concentrator is 69%,and the thermal efficiency of the whole system is 22.5%.The actual working output power under different months was compared and analyzed,and all met the working requirements.The overall system error was analyzed,and the system met the requirements of thermal power generation.In order to verify the safety and reliability of the model,the simplified model was imported into the finite element analysis software,the material of the mirror was selected polymethyl methacrylate,and the material of the grid was selected as aluminum alloy,and the modal analysis was carried out first,the fundamental frequency of the spliced concentrator was compared with the fundamental frequency of the circular open concentrator,and it was found that the spliced concentrator had a better structure than the rotating parabolic concentrator.Secondly,considering that the concentrator will be deformed by wind load during operation,the working conditions of different wind speeds and angles are analyzed,and the maximum deformation is7.77e-6 m,which meets the load requirements of the concentrator when working.At the same time,the harmonic response analysis of the concentrator is carried out,and the resonant frequencies that the model should avoid are 19.71 Hz,10.44 Hz and 9.65 Hz.Finally,because the concentrator will produce a large amount of thermal stress when working,the temperature field is set,and the maximum thermal deformation is solved,and thermal stress is the main cause of concentrator deformation.Through optical simulation and finite element analysis,the spliced concentrator system meets the requirements of thermal power generation performance,the structure is relatively stable,and the use of multiple regular hexagonal plane mirrors to replace parabolic mirrors reduces the production cost of mirrors,and has reference value for the application of solar thermal power generation systems.