Exploring the impacts of semi-transparent photovoltaic glazing on human visual and non-visual comfort: An experimental case study in Hong Kong

Semi-transparent photovoltaic (STPV) windows have promising potential for building carbon reduction. Most prior STPV studies primarily focused on energy performance. However, besides energy advancement, a healthy and comfortable indoor environment also has a high priority for buildings. STPV may influence indoor users' visual and non-visual perceptions since it absorbs certain solar irradiance and filters the passed-through daylight. There is an urgent need to explore their impacts on the occupants' visual and non-visual comfort via advanced psychophysical methods. This study conducted a visual and non-visual evaluation using a residential mockup installed with hollow semi-transparent photovoltaic (HSTPV) windows and a reference room with single clear glazing (SG) windows. The energy and optical performance of HSTPV windows was measured onsite. Thirty-six volunteers were invited to visit the two rooms, participating in two NCS colour tasks and a subjective questionnaire. Also, equivalent melanopic lux (EML) levels, electrodermal activity (EDA), and the heart rate of participants were assessed. In addition, a simulation campaign was conducted to provide general suggestions for HSTPV applications. The results indicated that: (1) both rooms meet the WELL standard's residential circadian daylight requirement; (2) consistent with device measurement and questionnaire feedback, the high accuracy of NCS colour tests showed that the HSTPV windows could provide as good colour rendering performance as SG windows; (3) compared to SG windows, HSTPV windows could provide users with more uniform perceptual experience on interior daylight distribution, and less glare issues; (4) occupants in rooms with HSTPV windows reported a neutral level of calmness or tension and moderate arousal status. 5) to apply HSTPV windows in high-density contexts, a 35%-40 % WWR was suggested for south-oriented rooms, while the 30-35 % WWR was suggested for west and east-oriented rooms.