New Fresnel Concentrator Structural Optimization Design

At present,the demand for energy are increasing with the development of society and the survival of human beings.The traditional non-renewable energy is facing exhaustion.The energy crisis has constrained the pace of social and economic development.Today,all countries are advocating sustainable development strategies,and the environmental pollution has become an urgent problem to be solved.The issues of environment caused by the burning of fossil fuels is becoming increasingly prominent,and the development and utilization of new energy sources is particularly important.As a clean and renewable energy source,solar energy has attracted much attention.It has a wide range of distribution,abundant reserves and no pollution to the environment.It is the most suitable clean energy for development and utilization.How to improve the efficiency of solar power generation and reduce the system cost is one of the important contents of the solar concentrator photovoltaic system research.Fresnel concentrator is a kind of concentrating device that is widely used in solar concentrating photovoltaic systems.Fresnel can concentrate sunlight at the focal point,which plays an important role in improving solar energy utilization.This paper designs a Fresnel-square composite parabolic concentrator based on the design theory of Fresnel lens and compound parabolic concentrator.At the same time,it elaborates the theory of Fresnel zone plate and designs a new type of stacked square Fresnel zone plate which is applied to the Cassegrain type concentrating system to provide certain design ideas for improving the uniformity of the spot and improving the service life of the solar cell.The specific research work is as follows:(1)The potential and value of solar energy are introduced.The research background and significance of this paper are described.The classification and working principle of solar concentrators are introduced in details,and the research status of solar concentrators is introduced.(2)The relevant theory of the solar concentrator and the evaluation of the concentrator ratio and spot uniformity of the concentrator performance are introduced.The theoretical knowledge of the Fresnel zone plate design is introduced in details,and the formula of the diffraction intensity of the square Fresnel zone plate is deduced.The application of the zone plate and the commonly used manufacturing methods are also introduced.(3)The design method of square compound paraboloids is introduced and modeled,and a Fresnel-square compound parabolic concentrator is designed based on Fresnel lens design theory.The incident spot and exit spot are compared by simulation.A uniform square spot suitable for a square-shaped photovoltaic receiver was obtained,and the uniformity of the spot when sunlight was non-parallel incident was simulated and analyzed.(4)According to the diffraction theory of the square Fresnel zone plate,a new type of stacked square Fresnel zone plate was designed.The diffraction characteristics were analyzed by simulation.A square Cassegrain concentrator was designed.The designed zone plate was applied to the designed concentrating system and its concentrating performance was simulated and analyzed.Derive the ratio of light gathering when sunlight is non-parallel.