Fully exploiting solar energy with building envelops: Experimental study on an adjustable photovoltaic green facade

An innovative adjustable photovoltaic green facade (APVGF) was proposed that combines an adjustable photovoltaic (PV) blind system with a green facade (GF), offering high flexibility, significant energy output, excellent architectural aesthetics, and considerable building energy-saving potential. Experimental evaluations with identical test boxes showcased the system's multifaceted benefits, including a notable decrease in the average daytime temperature of window glass by 4.2 degrees C and 5.2 degrees C for the GF and APVGF, respectively, with peak reductions reaching 9.7 degrees C and 13.7 degrees C. The interior air temperature was reduced by an average of 6.5 degrees C and 7.7 degrees C, with maximum reductions of 15.3 degrees C and 18.6 degrees C. Additionally, the GF and the APVGF reduced the daytime average light intensity inside the test box by 6837 and 7706 lx, reducing the glare risk. High temperatures and self-shading significantly reduced the power generation efficiency of the PV modules in the autoadjusting and 30 degrees fixed modes. However, the higher total equivalent irradiance (GE) received in autoadjusting angle mode resulted in daily power generation being approximately 17.2 % and 22.5 % higher than that in the 30 degrees and 90 degrees fixed angle modes. The APVGF system's key innovation is its dual-purpose design: it adjusts the angle of the PV blinds based on the sun's position and environmental needs, boosting PV efficiency, and it enhances the building's ecological and aesthetic value with a green facade. This system marks a breakthrough in green building tech and offers a new approach to urban sustainability.