不同集热策略下光伏/热一体化系统热电性能研究

Thermoelectric Performance Study of Photovoltaic/Thermal System with Different Heat Collection Strategies

为探究光伏/热一体化(PV/T)系统的热电性能受不同集热参数的影响,并解决流体反向加热光伏电池造成系统集热量损耗和发电量减少的问题,建立了PV/T系统三维瞬态数学模型,开发了一种新型集热控制系统,用于实时监控水箱水温和调控流程改变集水量,分析了集热管排数、排布方式、水箱容量、集热目标温度对PV/T系统温度、热电效率、集热量和发电量的影响。结果表明:随管排数增加,系统日集热量和日发电量均增加,但增幅减弱,管排数从8增加到10,发电量仅增加0.07%,集热量仅增加0.42%;集热管交错排布时,光伏电池温度均匀性最好;随着水箱容量增加,系统日发电量和日集热量显著增加,但水箱集热温度和集热品位均降低,与45 L水箱相比,65,85和105 L的日发电量分别提高1.48%,2.55%和3.35%,日集热量分别提高30.72%,53.30%和70.38%;与普通系统相比,新型集热控制系统的热效率和电效率分别提高13.14%和0.40%;新系统中集热目标温度设定越高,水箱集水量越少且系统电热性能越差。

In order to investigate the influences of different heat collection parameters on the thermoelectric performance of the integrated photovoltaic/thermal(PV/T)system,and solve the system problem of heat collection loss and power generation reduction caused by fluid reversely heating PV cells,a three-dimensional transient mathematical model of the PV/T system was established,and a new heat collection control system was developed to real-time monitor the tank temperature and change the water collection volume by process regulation.The effects of the heat-collecting tube row number,arrangement mode,water tank capacity and heat-collecting target temperature on the temperature,thermal and electrical efficiencies,heat collection and power generation of the PV/T system were analyzed.The results show that when the number of tube rows increases,the daily heat collection and daily power generation of the system both increase,but the amplification decreases,the daily power generation and daily heat collection only increase 0.07%and 0.42%with the tube row number from 8 to 10;the temperature uniformity of PV cells is the best for the heat-collecting tubes in staggered arrangement;as the capacity of water tank increases,the daily power generation and daily heat collection of the system increase significantly,however,the heat-collecting temperature and heat grade of the water tank both decrease.Compared to the water tank of 45 L,the daily power generation of 65,85 and 105 L increase by 1.48%,2.55%and 3.35%,and the daily heat collection increase by 30.72%,53.30%and 70.38%,respectively;the thermal and electrical efficiencies of the new heat collection control system are 13.14%and 0.40%higher than the conventional system respectively;the higher the heat-collecting target temperature of the new system is,the less the water collection volume of the tank is,and the worse the thermoelectric performance of the system is.