Thermal and carbon emission multi-objective optimization of photovoltaic skylights integrated large railway station in the cold zone of China

The semi-transparent photovoltaic skylight (STPV) can maximize the utilization of solar energy through both passive heat gains and active power generation. Therefore, applying skylight-integrated photovoltaic (SIPV) in railway stations has become an important measure to reduce carbon emissions in the cold zone of China. This study proposes a framework for SIPV variables optimization in such large space buildings. Firstly, solar heat gain coefficient, skylight-to-ground ratio, and tilt angle were selected out of five as key parameters for the next multi-objective optimization by a global sensitivity analysis. Then, a three-objective optimization based on the HypE algorithm was conducted, targeting maximum effective solar gain, minimum thermal discomfort percentage, and minimum operational carbon emissions. The result reveals that the optimal solution can reduce the operational carbon emissions by 16.2 %, increase the effective solar gain by 29.9 %, and reduce the thermal discomfort percentage by 9.3 % compared to the benchmark scenario. The recommended values are as follows: skylight tilt angle in the range of 0∼4°, skylight-to-ground ratio within either 1–2 %, 11–20 %, or 30 %, solar heat gain coefficient should be restricted to 0.2–0.24. The findings can provide a theoretical basis and scientific reference for SIPV application solutions among similar large-space buildings in regions with comparable climatic conditions.