Research And Analysis On Optical Properties Of Flat - Type CPC Collector For Spotlight Photovoltaic System

Energy has been associated with the development and progress ofthe human being, but as series of environmental problems of conventional energy consumption as well as the burning of fossil fuels come out, human beings have begun to look for the clean and renewable energy. Nowadays, human beings can develop and use renewable energy mainly in the form of hydropower, wind energy, biomass energy, geothermal energyand solar energy, since the solar energy for its large storage, subjected to geographical constraints, it has become the most extensive renewable energy used. There are two main forms of utilization of solar energy: power generation and solar thermal energy utilization.Solar power is the photovoltaic power generation mainly based on the principle of photovoltaic effect, by using of which solar cells can directly convert the solar energy into electrical energy. Photovoltaic power generation by geographical restriction factors is small, can be used in the world, countries around the world have introduced a variety of relevant mandatory policies to encourage photovoltaic industry research and development. Although, in recent decades, photovoltaic power generation is more and more widely applied, since for large-scale commodity production solar cell cost is expensive, the high cost of production become major obstacles for the world’s photovoltaic power generation applications. Condensing technology through the condensing system is cheaper; to converge the sun’s rays to efficient solar cells with small area, thus reducing the amount of solar cells to further reduce the power cost of the system.Concentrating photovoltaic system is mainly composed of high efficiency solar cells, condenser, cooling device, and tracking system. Compared to expensive, and the complexity of solar cells production, cheap concentrator has become an important part of concentrating photovoltaic system. Compound parabolic concentrator(CPC) can not only accept the direct radiation, but also the scattered radiation part, the spotlight can to less than 3 as fixed condenser, avoid to using the complex tracking system, reduce the concentrating photovoltaic power generation cost.This paper firstly analyzes the design principle of symmetric CPC flat type and non symmetric CPC, the symmetric CPC plate type reflection model, the two reflection model and non symmetric CPC a reflection models are: optical tracking simulation software Tracepro for validation, verification results show: comparing one reflection model two reflection model has higher accuracy between 0-10 degrees. After the calculation program, when acceptance angle equals to 20 degrees, a two reflection model, average efficiency factor are 0.94082, 0.93717, and0.93557, respectively, simulation obtained by using Tracepro, we can see that the two reflection model is more close to the simulation results. For the non symmetric CPC using TracePro optical simulation software to one reflection model is verified, the results prove that one reflection model has higher precision.According to the amount of annual radiation, the plate of symmetric and asymmetric results proves that: in the fixed angle mode(tilt angle= latitude), in Kunming, when the geometric concentrating ratio gC is less than or equal to 2.5, equals to symmetric type condensing effect, when the geometric concentration ratio gC >2.5, concentrating advantage asymmetric slowly appear. At the same time, all the results show that after cutting, flat plate type asymmetric better than symmetric.