An optimal and comparison study on daylight and overall energy performance of double-glazed photovoltaics windows in cold region of China

The semi-transparent photovoltaics (STPV) window is recognized by many as an innovative and emerging technology. However, the applications of building-integrated STPV windows are restricted to a certain extent by potential conflicts between the daylighting quality and energy efficiency. In this study, a novel metric named the ratio of N-Daylit area was derived to quantify the daylighting quality. On this basis, parametric analysis with different PV cell coverage ratios, window-wall-ratios (WWR) and orientations of double-skin STPV windows were performed to obtain annual daylighting quality and net electricity use for a generic reference office located in cold region of China. An optimal design of DS-STPV facing south with PV cell coverage ratio of 30% and VVWR of 30%-40% was recommended according to the simulation results. Furthermore, a comparison study of DS-STPV against with other five types of commonly used was also conducted. The results revealed that the utilization of STPV was beneficial for the improvement of daylighting quality and led to a reduction of annual energy consumption of the office. By using the DS-STPV, the ratio of N-Daylit area was increased to 56.8% with an increment of 31%, while the net electricity use of the space was as low as 36.1 kWh m(-2).yr(-1). (C) 2018 Elsevier Ltd. All rights reserved.