Comprehensive Utilization Of Thermal Radiation Energy Based On Upconversion And Non-imaging Devices

As the fundamental driving force of modern human society and economic development,energy is a significant guarantee for the development of national economy.With the exploitation and consumption of fossil energy,environmental crisis has become a common topic of national concern.Social development is faced with resource shortage,environmental pollution,climate change and other issues,which has an important relationship with the current energy structure.With the strategic deployment of the 14th Five-Year Plan,under the guidance of the overall objectives of "carbon neutrallity",the development and utilization of new energy technologies play an important role in changing the structure of traditional fossil energy.As a new energy,thermal radiation energy includes high temperature heat source radiation energy and solar radiation energy,which is of practical significance to study its utilization form.In this paper,we take the collection and utilization of thermal radiation energy as the main line and focus on the study and analysis of the use of radiation energy in three energy conversion systems:composite parabolic concentrator and thermoelectric devices,photovoltaic thermoelectric hybrid system,and upconversion materials and photovoltaic cells,and puts forward the optimization method of energy conversion system and verifies it by combing theoretical analysis with experiment.The main contents and conclusions of this paper are as follows:(1)Aiming at the scene which can generate high temperature heat sources,according to the principle of edge ray,a non-imaging parabolic concentrator for infrared radiation energy collection is designed and fabricated.Combining the concentrator with the thermoelectric geneator(TEG)significantly improves the overall performance of the device,and dicusses the effect of this combination on waste heat recovery and utilization.The research started with numerical simulation analysis,through the modeling of the thermoelectric unit and the thermoelectric device,the specific results of the output power and conversion efficiency improvement of the device by the parabolic concentrator are discussed and the analysis shows that the number of PN junctions in the device is greatly reduced,the output power and efficiency can be higher with CPC than without CPC.Finally,the experimental test system is built to further analyze the effect of CPC on the collection of thermal radiation energy and the peormance of thermoelectric devices.The advantage of the concentrator on the utilization of radiation energy and the role of the structure optimization of the thermoelectric device are obtained by the way of experimental verification.(2)The performance of photovoltaic thermoelectric hybrid system composed of different solar cell(mono-crystalline silicon cells and gallium arsenide cells)is studied through experimental measurement.The influences of solar cell type,concentration ratio,cooling temperature and load resistance on the output power and energy conversion efficiency of hybrid system are analyzed.At the same time,it is proposed that there is an optimal area ratio of solar cells and TEG for the hybrid system to obtain the optimal output power.At this optimal value,the maximum conversion efficiency of the hybrid system composed of gallium arsenide soalr cell and thermoelectric devices can reach 32.2%.The optimal value is optimized through machine learning method,and the performance of hybrid system is the best when the area ratio of solar cell and thermoelectric device is 4.41.The prediction results of machine learning are verified by experiments.By optimizing the structure parameters of photovoltaic thermoelectric hybrid system,the application of machine learning in improving the performance of energy conversion system is discussed,which provides a reference of the follow-up research.(3)The experimental research on photovoltaic cells based on up-conversion materials has been carried out.By understanding the luminescence mechanism of the up-conversion materials,the principle of the up-conversion materia for improving the performance of solar cells is analyzed.An experimental test system was set up to discuss the application of up-conversion materials in inproving the performance of solar cells.According to the summary and analysis of experiments,the use of up-conversion materials can increase the power and efficiency of double-sided monocrystalline silicon soalr cell by approximately 6.64%and 6.65%,respectively.By comparing the influence of up-conversion materials on the performance of solar cells under different concentrations ratios,it is concluded that the up-conversion materials have more obvious effect on the performance improvement of solar cells under high concentration ratio.