A Study Of Using Waste Heat Of Amorphous Silicon Solar Cells In Photovoltaic Systems

Cooling of the PV system is one of the key technologies for the applications of solar cells uesd in buildings. The solar-to-electrical conversion efficiency of amorphous silicon photovoltaic cells basically reaches 4% -13% in current engineering applications. Eighty percent of the energy absorbed by the solar cell is converted into thermal energy, causing rise in temperature of the solar cell, which largely reduces the power generation efficiency of photovoltaic cells. However, if the waste heat generated by solar cells can be used effectively, not only the temperature of photovoltaic cells can be reduced, but also the comprehensive utility efficiency of PV system can be improved.The thesis illustrates the technical principles and characteristics of PV/T systems, analyzes the development and the utilization of the PV/T systems at home and abroad and at last makes a summarize for this question.Two major patterns of photovoltaic thermal systems, which are PV/T water systems and PV/T air systems, are illustrated in this thesis, consisting of its technical principles and characteristics. Furthermore, the two major patterns were studied by theoretical simulation method, and the impacts of the Characteristics Parameters of PV/T systems were analyzed.Besides, the amorphous silicon PV/T experimental systems, which applied to BIPV, were built. The influence of the different operating conditions of amorphous silicon PV/T systems on the temperature of the solar cell and the thermal efficiency were studied through a series of experiments. And moreover the system performance characteristics were studied when the PV/T experimental systems maintained high net output efficiency.In this study, the two patterns of PV/T system showed good performance. The simulation results are well with the experimental data. The data obtained in this paper can provide a reference for the installation of the a-Si solar cells applied in BIPV and a method for the utilization of the waste heat, which can improve the comprehensive utility efficiency of PV system.