Experimental Investigation On The Solar Photovoltaic Semiconductor Refrigeration/Heating System

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.