Theoretical-experimental-simulation research on thermal-daylight-electrical performance of PV glazing in high-rise office building in the Greater Bay Area

Building-integrated photovoltaic (BIPV) technology shows a promising future in high-density cities given its potential to fully utilise the limited floor space for renewable energy generation. This study proposes a transient heat transfer model of a Cadmium Telluride semi-transparent PV glazing (CdTe SPVG) to analyze its heat transfer process validated by field experiment. The dynamic experiment also tests the thermal-daylight-electrical performance of the CdTe SPVG comparing with conventional insulated glazing unit (IGU) on a testing building. The simulation model is established based on the experiment to explore the annual energy performance of the CdTe SPVG applied in a practical high-rise office building in the Greater Bay Area comparing with the single glazing (SG), IGU and CdTe semi-transparent PV vacuum glazing (SPVVG). The experimental results show that the dynamic solar heat gain coefficient of the CdTe SPVG is about 0.32∼0.54 lower than the IGU at about 0.46∼0.67. The CdTe SPVG reduces an average of 18% indoor heat gain compared to the IGU during the testing period. The U-value of the CdTe SPVG ranges from 4.10∼5.38 W/(m2·K) compared with the IGU ranging from 2.44∼2.91 W/(m2·K). The CdTe SPVG ensures the indoor daylight illuminance over 450 lux with a useful daylight illuminance rate of about 98%, and its maximum daily power generation is 106 Wh (1.16 Wh/Wp). The simulation results of four different glazings show that the annual building energy consumption using the SG is about 116 kWh/m2, while it is obviously reduced using the IGU (-2.16%), CdTe SPVG (-6.52%) and CdTe SPVVG (-12.51%). The annual power generation of the CdTe SPVG is about 894.73 MWh (0.64 kWh/Wp) equivalent to about 421.87 tons CO2, which accounts for about 15.81% of the annual building energy consumption. This comprehensive study reporting the transient heat transfer process, dynamic experimental performance and annual building energy consumption of the CdTe SPVG can provide theoretical basis to the development of BIPV in the Greater Bay Area. The developed theoretical-experimental-simulation models can also be applied in other regions to access the pathway towards zero energy and zero carbon of the building sector.