Research For Energy And Exergy Efficiencies Of Solar Thermoelectric Generator

With the constant development of the human civilization, the demands for electricity power are becoming increasingly larger in modern society. Solar thermoelectric generation is a type of electricity generating technology, which could convert the solar power to electricity power. It has the advantages of high reliability, non-pollution and peaceful operations with immovable parts, so which is a green and environmentally-friendly technology. Following the development of thermoelectric materials and practice application, it will be used progressively more in the future, and the best economical measures of it could also bring on an energy revolution and substitute for conventional energy sources. So, a series of study for solar thermoelectric generator system is presented in this paper, and several proposals have been brought forward, mainly as follows:First of all, based on the steady heat conduction equation, thermodynamic analysis is performed on an essential unit of thermoelectric devices, and a mathematical modeling is set up. The calculating formulations for the output power and generating efficiency of the power generation are deduced. At the same time, a thermoelectric analysis model is founded by use of, the finite element method with ANSYS. With the same material properties and boundary, calculations for mathematical model and finite element model are carried out, and the results are compared.Secondly, on the basis of thermoelectric unit analysis using ANSYS software, the actual solar thermoelectric generator models are constituted, according with their actual working conditions, Boundary conditions are imposed on. Effects of the heat convection and radiation are considered. The temperature function, electromotive force, short current, output power and thermal efficiency of thermoelectric devices are obtained. In the situation of different energy input, models are calculated. The thermoelectric generating parameters are obtained with the changes of focalizing ratio.In addition, an effect analysis for the thermal generating capability on material properties is completed. The law of thermoelectric efficiency and power output changed with the collector's absorption rate, firing rate and the thermal conductivity is found out. The requests for collector's material attributes of a solar thermoelectric plant have been specified. Finally, affecting factors such as the heat convection, cold port temperature and load are investigated, and on the base of this work, the main factors impacting on the thermoelectric generating capability are identified. Measures to improve the performance obtained, and the schemes for enhancement under the ? current situation are discussed.Finally, a model of solar thermoelectric device exergy analysis is setup. On the basis of the efficiency study, the thermal exergy efficiency of the device is analyzed, and the law of exergy efficiency changes coming with the condenser's exergy efficiency ratio, collector material emissivity, and collector's thermal conductivity, heat convection ratio, cold-temperature and load are found out.This paper is mostly using finite element software ANSYS to model and calculate the solar thermoelectric generator performance under different boundary conditions and material properties. Some of the results will have an important reference to design and making.