Comfort assessment and energy performance analysis of a novel adjustable semi-transparent photovoltaic window under different rule-based controls

Self-powered photovoltaic windows, which integrate photovoltaic with electrochromic devices, have attracted widespread attention of scholars since they can generate electricity in situ and reduce building energy consumption by modulating the transmitted solar radiation. However, previous studies mainly focused on the material development and performance characterization, lack of comfort assessment and energy saving potential of its application to buildings. To address this issue, an adjustable semi-transparent photovoltaic (ATPV) window which integrates CdTe-based photovoltaic and WO3-based electrochromic, was taken as the research object, and a novel rule-based control strategy taking the beam solar radiation luminous efficacy (CtrlEff) as decision variable was proposed for the first time. The ATPV window model was established in WINDOW software based on the measured data, and then it was exported to integrated with a medium office building model in EnergyPlus for performance evaluation including the visual comfort, thermal comfort, net energy consumption, and net-zero energy ratio. The results of a case study in Changsha (E 112 degrees, N 28 degrees) indicated that the ATPV window under the CtrlEff strategy can effectively reduce the southward and westward intolerable glare by 86.9% and 94.9%, respectively, and increase the thermal comfort hours by 5% and 2%, compared to the Low-E window. Furthermore, the net-zero energy consumption can be decreased by 58.7%, 65.7%, 64.1%, and 53.8% for south, west, east, and north orientations, and the corresponding net-zero energy ratios are 65.1%, 54.6%, 62.7%, and 61.6%, respectively. The findings of this study provide new strategies for the control and optimization of the adjustable window.