Research On Concentrating Photovoltaic-thermoelectric Hybrid Method And System Performance

Among many renewable energy sources,solar energy has attracted much attention due to its abundant reserves and wide distribution,and has the greatest potential for development.Solar photovoltaic-thermoelectric(PV-TE)hybrid technology is an emerging solar energy utilization technology,which is based on solar photovoltaic(PV)utilization technology.For PV cells,photons with energy equal to the band gap of the PV cell can excite electron-hole pairs,and the remaining energy will be wasted in the form of heat.The wasted heat includes thermalazaiton and photons with energy smaller than the band gap of the PV cell.Since the thermoelectric module has the ability to directly convert heat energy into electricity,the thermoelectric module is introduced into the solar PV cell system to construt a PV-TE hybrid system that more fully utilizes solar energy.To reduce the cost of the system and enhance the competitiveness of the PV-TE hybrid system,concentrating elements are used to increase the solar radiation intensity on the surface of the PV cell.Since the uneven radiation intensity distribution generated on the surface of the PV cell by the concentrating element affects the efficiency of the PV cell,it is necessary to improve the concentrating system to improve the uniformity of the radiation distribution.The increase of the radiation intensity on the PV cell will amplify the influence of thermalazation and low-energy photons on the temperature of the PV cell.In addition,it is necessary to solve the temperature mismatch between the PV cell and the TE module.To solve the above problems and improve the solar energy utilization rate of the concentrated photovoltaic-thermoelectric(CPV-TE)hybrid system,the main purpose of this article is to study the performance adjustment mechanism of the photovoltaic thermoelectric coupling system.The specific research content includes the following aspects:1.Design of concentration lens with uniformity concentrated light spotsBased on the solar concentration photovoltaic power generation system,a new concentration lens design method with uniform irradiance distribution for concentrated photovoltaic cell systems is proposed.According to the geometrical optics principle of Fresnel lens design,the theoretical model of the condenser lens is established,and the light tracing simulation analysis of the concentration lens is carried out by Monte Carlo method.The performance of the new concentration lens is compared with the performance of the Fresnel lens.2.Thermodynamic theory model and theoretical analysis method of concentration photovoltaic-thermoelectric hybrid systemAdding light-concentrating elements to the photovoltaic-thermoelectric hybrid system can increase the solar radiation intensity per unit area on the surface of the photovoltaic cell and effectively reduce the system cost.Analysis of the irreversible loss of energy in the process of energy transfer in the concentrating photovoltaic-thermoelectric hybrid system,and an in-depth understanding of the transfer law of solar energy in the system requires the analysis of the second law of thermodynamics.Analyze the irreversible loss mechanism of solar energy in the hybrid system,and study the methods to reduce the irreversible loss.3.Experimental study on performance control mechanism of concentration photovoltaic-phase change material-thermoelectric hybrid systemIn the concentration photovoltaic-thermoelectric hybrid system,due to the function of the concentrated system,the problem of temperature mismatch between the photovoltaic cell with negative temperature coefficient and the thermoelectric module is more serious.The phase change material with the function of temperature regulation is used,combined with the three-junction In Ga P /In Ga As/Ge photovoltaic cells and phase change materials establish a photovoltaic-phase change material-thermoelectric(PV-PCM-TE)hybrid system to improve the solar energy utilization efficiency of photovoltaic cells.The effects of the concentration ratio,the uniformity of the focused spot,the hybrid mode of the photovoltaic cell and the thermoelectric module,and the cooling conditions on the hybrid performance are studied.Phase change materials have the function of reducing and stabilizing the temperature of photovoltaic cells.The effect of phase change materials on the performance of photovoltaic-thermoelectric coupling system is studied.4.Theoretical model,theoretical analysis method and experimental research of concentration solar photovoltaic-thermoelectric hybrid systemIn order to make full use of the high-temperature thermal radiation energy emitted by the emitter that cannot be used by the thermophotovoltaic cell in the concentration thermophotovoltaic cell system,and to solve the problem of the temperature interaction between the thermophotovoltaic cell and the thermoelectric module,a new type of thermophotovoltaic-thermoelectric(STPV-TE))theoretical model and analysis method of the hybrid system is proposed.According to the results of the theoretical analysis of the hybrid STPV-TE system,the hybrid STPV-TE experimental system is established to verify the feasibility of the STPV-TE system,and to study the influence of the absorber/emitter temperature on the temperature of the thermophotovoltaic cell and the temperature of the thermoelectric module.Under the same cooling conditions,compare the performance of a single STPV system and a STPV-TE hybrid system.