相变蓄热式光伏建筑一体化系统的传热传质及电学性能机理研究

目前，广泛应用的晶硅光伏组件只能转换一小部分入射的太阳能（10-15%），其中大部分转换为热能，使组件的温度升高，从而输出特性受到影响导致功率明显下降。将相变材料（PCM）置于组件背面是一种极具潜力的降温方式，但已有的研究只针对PCM给光伏板降温，对如何回收利用PCM中蓄存的热量研究甚少。此项目以提高组件的光电效率和余热再利用为目标，提出一种光伏建筑一体化（BIPV）与相变材料相结合的集成系统，通过PCM冷却太阳电池达到提高光电效率的目的，同时回收蓄存的低温热量用于采暖或生产生活热水，形成太阳能梯级利用和电热联产的创新性思路。本项目拟结合传热学与电学的研究方法，对BIPV-PCM电热联产系统运用能量守恒定律，建立热电数学模型，分析系统在工作过程中光-电-热的转换过程，研究内部温度分布、动态传热传质过程和组件的电力输出性能。计算系统的可用能效率，分析热电输出耦合性能，并进行优化及实验验证。

Currently, a key challenge of crystalline silicon photovoltaic (PV) modules is that only 10-15% of incident solar energy can be converted to electricity, while the majority of the remaining part is transformed into heat, which may induce the working temperature of the PV panels up to 100 ºC and further reduce the PV conversion efficiency by 0.4-0.65%/ºC. The emerging technology that attaches phase change materials (PCMs) at the back of a PV panel is a promising method to cool down PV panel and increase energy conversion efficiency. However, little research was conducted to utilize the thermal energy stored in the PCMs for serving the buildings. This research proposal aims to develop a novel hybrid building integrated photovoltaics (BIPV) cladding with PCM, called BIPV-PCM system. This system can achieve higher PV conversion efficiency and utilize the thermal energy stored in PCMs for building concerned, such as hot water, space heating and other in-house drying processing. This project will develop the mathematical model of heat and mass transfer, and the model of PV power generation, based on the law of conservation of energy in the hybrid system. The conversion process between solar energy, electricity and heat will be studied, and the exergy efficiency of incident solar radiation will be calculated. The prototype of the novel BIPV-PCM system will be developed and tested in our lab to validate the simulation results.