Determining the optimal visible light transmittance of semi-transparent photovoltaic considering energy performance and occupants’ satisfaction

Abstract

With the increasing use of front windows such as curtain walls, the application of semi-transparent photovoltaic (STPV) systems is effective in producing renewable energy, reducing cooling load via solar radiation control, and improving visual comfort. However, in STPV, the visibility of the view from a window decreases, and this can have a negative impact on the occupants' satisfaction (i.e., psychological satisfaction, task performance, and task load). Therefore, this study sought to present the optimal visible light transmittance (VLT) of STPV that simultaneously considers energy performance and the occupants' satisfaction according to the azimuth of a building. To this end, a residential building in South Korea was selected, and energy performance according to the VLT of STPV (amorphous Si thin film PV) was analyzed using DesignBuilder and EnergyPlus for STPV with three VLTs (i.e., 10%, 20%, and 30%). In order to analyze the occupants' satisfaction according to the VLT of STPV, 31 participants were recruited, and an experiment using virtual reality (VR) was carried out. Multi-objective optimization was performed using the energy performance, psychological satisfaction, and task load. The results showed that as the weight of energy performance was adjusted to 0.33, 0.5, and 0.6, the optimal VLT of STPV was 25.53%, 22.65%, and 20.85% on average, respectively. It is expected that the findings of this study can allow the building owner or building designer to predict the energy performance, the occupants’ psychological satisfaction and task load according to the VLT of STPV.