Research On The Solar Thermophotovoltaic Devices Based On Metamaterials

With the increasing scarcity of energy and the continuing deterioration of the environment,governments around the world are committed to seeking new,clean and sustainable energy sources.As a kind of clean energy and renewable energy,solar energy has superiority that cannot be matched by fossil fuels and is therefore exploited by various countries in the world.Solar thermal photovoltaic power generation is a new way for solar thermal utilization.Solar thermal photovoltaic system has the advantages of high power density,high conversion efficiency,no moving parts,and easy maintenance compared with general solar photovoltaic systems,and has broad application prospects.Especially in today’s China,the research on solar thermal photovoltaic systems has become even more urgent.In this work we study the operating mechanism of solar thermal photovoltaic systems and optimize the various components.First,We establish a complete physical model for the solar thermal photovoltaic system and analyze its operating principle.By analyzing the working principle of each component,we optimize its efficiency to improve the overall efficiency.We analyze the Kirchhoff’s law,the principle of heat radiation,and the selectivity of the metamaterials and one-dimensional photonic crystals to sunlight,and the bandgap of photovoltaic cells.All of these provide necessary theoretical guidance for the optimal design of solar thermal photovoltaic systems.Second,A cross-structure selective absorber based on metamaterials is proposed.Metamaterials are artificial materials designed with extraordinary physical properties.Terahertz absorbers based on metamaterials have many potential applications in solar thermophotovoltaics.This work focuses on the selective radiators of the system.According to Kirchhoff’s law,the absorption rate of an object is equal to the emissivity.Researching selective radiators is equivalent to studying selective absorbers.A cross-structure selective absorber is designed based on the characteristics of the metamaterial absorber and theoretical analysis is performed.The simulation results show that the absorber has an absorption rate of 99.6% at a frequency of 129.3 THz and a wavelength of 2.33 μm,which can be matched with InGaAsSb photovoltaic cells.The material of the wave absorber is selected from tungsten and aluminum oxide,which can meet the requirements of working temperature of solar thermal photovoltaic system.Third,A filter based on one-dimensional photonic crystals is proposed.This article focuses on the filter of the system.The optical filter is used to realize the optical matching device between the thermal radiation and the thermo-photovoltaic cell,and the main function is to pass the light in the band required by the photovoltaic cell,and the light reflection and re-heating radiator that cannot convert the photovoltaic cell into electric energy is reused.Optical filters directly affect the conversion efficiency of thermal photovoltaic systems,so it is particularly important to study their selection characteristics.We uses Macleod to design a kind of one-dimensional photonic crystal filter and carry out theoretical analysis.The simulation results show that the filter cut-off wavelength is 2μm,the short-wavelength average transmittance is greater than 70%,and the long-wave average reflectance is greater than 90%.It can be matched with the GaSb photovoltaic cell and can greatly improve the efficiency of the solar thermal photovoltaic system.