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太阳能光伏发电半导体制冷/制热系统的实验研究
Experimental Investigation on the Solar Photovoltaic Semiconductor Refrigeration/Heating System
【作者】 郭智群;
【作者基本信息】 中南大学 , 热能工程, 2011, 硕士
【摘要】 太阳能是一种取之不尽、用之不竭的绿色能源,半导体制冷具有体积小、重量轻、无噪声和无泄漏等优点。本文设计了利用太阳能光伏发电为半导体制冷器提供直流电对空间进行制冷/制热的系统,该系统具有结构简单、可靠性高、无污染等优点,特别适合没有架设电网的边远地区的冷藏/暖藏箱等应用,对推进太阳能光伏发电半导体制冷/制热系统的市场应用有一定参考意义。本文主要开展并完成以下工作:1、在分析太阳能光伏发电和半导体制冷器的基本原理、运用及发展现状的基础上,设计并搭建太阳能半导体制冷/制热系统。系统由太阳能单晶硅光伏电池、半导体制冷器、充放电控制器、蓄电池和数据采集系统等部分组成。2、从理论上研究了太阳能电池的I-U特性、照度特性和温度特性,及光伏电池的等值电路,根据长沙地区的天气状况,对太阳能电池在不同情况下的运行特性进行了实验研究。实验得到太阳能电池最佳倾角约为20°。研究不同工况下电池的I-U特性,得出太阳能电池的填充因子约为0.58,转换效率约为8.47%。测试不同太阳辐射下太阳能电池的工作参数得出:给定温度情况下,短路电流Isc随太阳辐射强度的增加线性增加,开路电压Voc随太阳辐射强度的增加呈对数增加,辐射高于300 W/m2时趋于饱和;在辐射强度一定时,短路电流随着温度的升高而增加,开路电压Voc随温度的升高而减小。3、分别对该系统的制冷和制热性能进行实验研究。制冷实验研究得到:制冷空间温度随着制冷器工作电流I的增大而先下降后升高,随着热端风扇功率的增大而下降,随着环境温度的增大而升高。制热实验研究得到:产热量QH随工作电流I的增大而增加,因此通过调节工作电流可以准确控制制热空间温度。4、对本实验所设计的太阳能制冷/制热系统的成本及减排效益进行分析。当使用寿命为20年时,系统年平均费用约为361元;实验所设计的太阳能发电系统替代煤发电,减少有害物质排放总量为0.682吨,总的减排效益约3536.28元。
【Abstract】 Solar energy is a green and inexhaustible energy, semiconductor cooler is small, light weight, no noise and leakage. In this dissertation, the system of solar photovoltaic power generator providing direct current for the semiconductor cooler of a small cooling/heating cell is designed. This system is simple structure, high reliability and no pollution, particularly suitable for refrigeration/heating applications such as the cooling/heating box in remote areas without setting up the grid, and it has certain significance to promoting the commercial application of solar photovoltaic refrigeration/heating.Several works have been done in this paper:1、Based on the analysis of the basic principles, development and application of the solar photovoltaic and semiconductor cooling, a experimental solar photovoltaic semiconductor refrigeration/heating system is designed. This system is composed of solar mono-crystalline silicon cell, controller, battery, semiconductor refrigeration/heating system and data acquisition system.2、The voltage-current characteristic、illuminance characteristic、temperature characteristic, and the equivalent circuit of photovoltaic cell are investigated theoretically. The performance characteristics of photovoltaic cell under different weather conditions at Changsha district are experimented. The experiment shows that the optimum angle of the solar photovoltaic cell is about 20°. The fill factor of solar energy cell is almost 0.58, and the conversion efficiency is about 8.47% in the voltage-current characteristic experiment. The tests of the solar photovoltaic operational parameters under different solar radiation shows, at the given temperature, with the increase of the solar radiation intensity, the short-circuit current increases linearly, and the open-circuit voltage increases logarithmically. If the radiation intensity is more than 300 W/m2 the open-circuit voltage is nearly invariable. When the radiation intensity is constant, with the increasing of the temperature, the short-circuit current is increased, and the open-circuit voltage is decreased.3、The cooling and heating performance of the system were investigated respectively. In refrigeration experiment, when the operating current of the cooler increases, the temperature inside the cell is first decreased and then increased. With the increase of the power of the fan, which is connected with the hot end of the cooler, the cell temperature is decreased. With the increment of environmental temperature the cell temperature is increased. In heating experiment, with the increase of the cooler operating current, the heat production is increased. So the temperature inside cell can be controlled exactly by adjusting the cooler operating current.4、The operation cost and the benefit due to energy saving is analyzed. For 20 years life expectancy, the average annual cost of this experimental system is 1,200 Yuan. By substituting coal with solar energy, the reduction of the harmful substance emission is 0.682 t, the total benefit of the reduction of harmful substance emission is 3536.28 Yuan for the system.
【Key words】 Solar energy; Photovoltaic generation; Semiconductor refrigeration; Cost analysis;