Quantitative assessment on the visual effects of photovoltaic double skin façade: Towards a sustainable building prospect

Photovoltaic double-skin façade (PV-DSF) plays a pivotal role in sustainable building prospects, with extensive research focusing on energy efficiency. However, its visual effects, though critical for daylighting comfort, have frequently been overlooked. This paper addresses this gap by conducting preliminary experiments and spectrum-resolution modeling to quantitatively assess the visual effects of PV-DSF, offering a fresh perspective on this critical aspect. Preliminary experiments reveal that PV-DSF with 20 % CdTe module slightly outperforms that with 40 % CdTe module in general color rendering index (R_a) by ∼0.8, while the laminated layer exerts negligible impact on visual effects. Spectrum-resolution modeling indicates that PV-DSF with CdTe modules achieves an optimal balance between energy efficiency and visual effects, with ∼80 % of correlated color temperature (CCT) and 100 % of R_a falling within desirable ranges. Correlation analysis reveals that CCT is particularly sensitive to factors influencing diffuse radiation fraction, such as radiation and water vapor, with remarkable correlation coefficients of 0.71 and 0.54. Meanwhile, R_a is primarily affected by the concentrations of colored atmospheric components (e.g., NO_x and O₃), with typically lower correlation coefficients ranging from 0.2 to 0.4. These correlations also explain the seasonal variations of visual effects, with CCT peaking in summer and R_a peaking in winter.