热开关控制光伏/温差联合发电装置设计提高发电效率

    Design of PV/TE hybrid power generation device based on thermal switch and its improving efficiency of power generation

    • 摘要: 为解决光伏电池板接收太阳辐射发电时板面温度上升导致光电转换效率下降的问题,该文通过温差发电技术对光伏电池板进行主动冷却;同时为解决温差发电技术因温差较小时热电转换效率低下的问题,引入热开关对装置进行控制,并采用扁平热管作为传热单元,利用水对流为系统进行冷却。为测试基于热开关的光伏/温差联合发电装置的性能,分析了不同光辐射强度、不同板面温度、以及不同冷端温度对系统的影响,并搭建试验平台,对联合发电装置进行试验研究。结果表明,装置联合发电效率高于单独一种发电方式的效率,实现了能量的梯级利用。在对装置进行瞬时性能测试期间,发电效率最高达到19.45%,发电功率最大达到32.15 W。在6 d全天性能测试期间,联合发电装置的平均发电效率为17.72%,最高可达18.37%。所获电能基本可以满足农业温室大棚检测系统、远程传感器的供电要求。

       

      Abstract: Abstract: In order to solve the problem of inefficiency of photovoltaic conversion caused by temperature rise when photovoltaic cell panel generates the electricity after receiving solar radiation, the present paper discussed about a method that the thermoelectric power generation technology could cool down the photovoltaic cell panel, this method was a kind of active cooling mode. However, when the temperature difference between the hot side and cold side of thermoelectric generator was close to each other, the thermoelectric conversion efficiency was too low, which had a negative effect on the device. To solve the above problem, the thermal switch was adopted to control the equipment, the switch would close when the temperature of the photovoltaic cell panel reached the predetermined value, and the heat passed down. On the contrary, the switch was in the off state. Through the control of the thermal switch, the thermoelectric generator could work stably and efficiently in the working range. Meanwhile, it could also improve the adaptive capacity to environment of the device. At the same time, the flat heat pipe had been chosen as the heat transfer unit, using water convection to cool down the system. After cooling the photovoltaic cell panel, not only its temperature would decrease, but also the service life could be extended. On the other hand, the cold side temperature of the thermoelectric generator could also decrease. Firstly, the present paper analyzed the effect caused by different intensity of optical radiation, different panel temperatures and different cold side temperatures in the system. Secondly, the whole experimental platform of system had been established. Last but not the least, the hybrid power generation system had been examined so as to test the property of hybrid power generation equipment which was based on PV/TE (photovoltaic/thermoelectricity) of thermal switch. The result revealed that the efficiency of hybrid power generation equipment was higher than a single electricity generating method included the photovoltaic power generation mode and the thermoelectric power generation mode. At the same time, the gradient utilization of energy could be realized by the equipment. In view of the experimental equipment had been built, the performance of the PV/TE hybrid power generation device based on thermal switch was investigated in two different ways, including the instant property and full-day performance test. The instant property of the PV/TE hybrid power generation device based on thermal switch was tested during 08:00-18:00 on August 27, 2017. The results showed that the efficiency of power generation could reach the peak point of 19.45% and the output of power generation could reach the peak point of 32.15 W. The full-day performance of the PV/TE hybrid power generation device based on thermal switch was tested from August 22 to 27, 2017. The results showed that the average power generating efficiency of the PV/TE hybrid power generation device based on thermal switch could reach 17.72% and its highest point could reach 18.37%. The test place was located in Northeast Agricultural University, Harbin. Finally, the test results showed the electricity acquired could basically meet the power supply needs of testing system of agricultural greenhouse and remote sensor.

       

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