An experimental and modeling study of thermal behavior of photovoltaic-greenery system

The combination of photovoltaic and greenery (PVG system) has received increasing attention in the city. However, the characteristic of thermal behavior for PVG system has not been fully revealed. Therefore, a field experiment was carried out to compare the local microclimate between PVG system and a lawn. And the results show that PV array cooled the below vegetation up to 2.5 °C in the daytime, but warmed the vegetation up to 0.7 °C at night. Energy balance analysis shows that, under the effect of PV shading, evapotranspiration consumed about 43.8 % of the total heat gain, and followed by longwave radiation (29.5 %) and heat convection (26.7 %). A numerical model considering the multiple thermal interactions between vegetation and PV modules was developed and validated by the measured data. Based on the parametric analysis, it’s found that higher plant species is preferred for PVG system, which has a greater cooling effect than the lawn. And a scenario simulation shows that, among the four factors usually neglected in the existing heat transfer model of PVG system, longwave radiation leads to the most significant error. The conclusions drawn herein could provide reference for the design optimization and energy performance prediction of PVG system.