Theoretical And Experimental Study Of Concentrating Solar Electricitry Generation Technology With Dielectric Multilayer Filter

The solar radiation coming to earth have broad range of wavelengths in the spectrum and the irradiance is low. A spectrally selective approach will always be possible to achieve a higher efficiency than normal by using a concentrator to concentrating the solar energy, with a good chioce of convertors matching the solar spectrum.The thesis focus on the crystalline silicon photovoltaic(PV) solar cells, try to investigate an approach to utilize the whole solar radiation spectrum efficiently with the hybrid PV-TEG(thermoelectric generator) system and the hybrid PV-DS(dish Stirling) system. The design strategy of the filter used in the hybrid systems will be decided on the basis of the characters of silicon cells, TEG and DS.First, a theoretical discussion of the concept of ’solar energy’is presented; the main characteristics of solar radiation in China are analysed. A review of the various concentration soalr power systems, spectral beam splitting systems and other solar electricity generation technologies proposed in the literature is presented, which concludes that there is a potential for increased conversion efficiency in the hybrid receiver systems with a filter.An introduction about the basic methords of the optical thin-film design is presented. The electromagnetic wave theory is used to analysis the interaction of the incoming sunlight with the thin-film. The relationship between optical properties of thin-film filter and the main physical parameters of the film, such as material properties and structural characterisitics, is discussed. A combination of the analytical design method and the computer-aided numerical method is used to get the fianl design results of the filters in this thesis.According to the typical parameters of the TEG, DS systems and the silicon cells performances, all the requirements of the filters are determined. The dielectric materials which are stable in the fabrication process are selected as the design materials. The starting design of each filter is calculated with an analytical design method according to the design target. The needle method is used to optimize the starting structures to obtain the fianl results of three different requirements. Two types of the filter samples are produced by an electron beam heating evaporation coating method, a good testing performance is achieved.With natural sunlight in outdoor conditions, power generation efficiencies of different silicon cells with varies filters under varies concentrating ratio are tested. The filters significantly optimize the short-circuit current and maximum output power of the solar cells, mean while, the actual efficiency of silicon cells and the overall power generation efficiency are improved.A calculation model for a hybrid PV-TEG system using the fabricated thin-film filter is proposed. A hybrid system combining photovoltaic cells with a solar-powered Stirling engine using the designed filter is analyzed. The calculated results show the advantages of this spectrally selective method for solar power generation.The direct radiation spectrum of Hangzhou in typical weather conditions at different time points are obtained by the solar radiation analysis model SMARTS. The calculated results are used to analysis different solar power systems like CPV, DS, PV-TEG and PV-DS. The benefits of the filter for hybrid solar power systems are demonstrated.