Enhancing building efficiency: Multifunctional glazing windows with integrated semitransparent PV and selective liquid-filters

Building integrated photovoltaic (BIPV) fenestration is presently regarded as a promising technology with multiple features. Nevertheless, the significant obstacle to achieving widespread use of this technology lies in striking a balance between enhancing its power conversion efficiency (PCE) and preserving the interior thermal comfort and visible transmission (VT). This work focuses on the development of a multifunctional window (MFW) that optimizes solar spectrum utilization and enhances the thermal efficiency of the BIPV window. This is achieved by combining semi-transparent photovoltaic (STPV) cells with a selective liquid filter (SLF) in a mono-glazing structure. The energy generation, building energy performance, and indoor lighting capabilities of the MFW are examined compared to existing glazed windows using 3D numerical models associated with analysis of variance (ANOVA). The findings indicate that incorporating SLF improves overall power generation, decreases energy consumption for air conditioning, stabilizes thermal performance, and boosts indoor comfort. Furthermore, the study underscores the substantial potential for energy conservation through the MFW, underscoring the significance of maintaining a harmonious equilibrium between energy production and indoor environmental comfort. Given that winter highlights the crucial relationship between energy advantages and indoor comfort, we examined five different types of MFW designs. In tough winter conditions, the fifth MFW design mode, which employs directional inward solar irradiation and features an air cavity on the exterior side and a stationary SLF on the internal side, demonstrates outstanding performance. By integrating the revolutionary MFW concept into building facades, this research can provide useful insights for improving the design of BIPV windows.