Comparative Analysis of Semi-Transparent Photovoltaic Skylight and Traditional Roof Glazing

Semi-transparent photovoltaic (STPV) skylights can generate electricity while meeting the needs of indoor lighting, which has an impact on building energy consumption. In this paper, we analyzed a double-layer semi-transparent photovoltaic (DL-STPV) skylight with a light transmittance of 20% in Beijing based on the established and verified model, and compared it with two types of traditional roof glazing. An equivalent electrical method was used to evaluate the energy performance of the DL-STPV skylight. In summer, the total equivalent electricity of the DL-STPV skylight is 7.0 kWh/m2, which is 103.3 kWh/m2 lower than that of double skin insulating glazing (DSIG) and 83.2 kWh/m2 lower than that of DSIG with Low-E, respectively; In winter, the total equivalent electricity of DL-STPV skylight is –44.9 kWh/m2, which is 34.7 kWh/m2 lower than that of DSIG and 31.3 kWh/m2 lower than that of DSIG with Low-E, respectively. The results showed that the DL-STPV skylight in Beijing reduced the air conditioning load in summer and increased the heating load in winter. Although the model used in this paper ignores the heat storage effect of the glazing itself, it is estimated that the loads of air conditioning, refrigeration, and heating are still decreasing, and the annual reduction is significantly reduced.