Investigation on the operating characteristics of a directly-attached light crystalline silicon PV roof

The building-integrated photovoltaic (PV) technology can alleviate electricity consumption during peak usage time. However, there are heavy and fragile problems in traditional silicon PV modules while low efficiency and poor stability in thin film modules. Hence, in the present study, a novel lightweight crystalline silicon PV module is first proposed. Then an electro-thermal coupling model for the novel lightweight PV roof is established and an experimental verification test platform based on four different substrates was built. Based on the data of typical meteorological days, the characteristics of operating, energy saving, and emission reduction of the novel lightweight PV roof in summer are analyzed. Finally, the influences of substrate thickness and wind speed on the characteristics of operating, energy-saving, and emission reduction of the novel lightweight PV roof are revealed. The results show that compared with the conventional roof, the lightweight PV roof slightly increases the building cooling load, but the electricity benefits guarantee the lightweight PV roof with a good building energy-saving effect in return. Among different substrates, the PV roof based on asphalt substrate achieves the best PV performance, building energy saving and emission reduction. The PV performance and the building energy saving of the lightweight PV roof based on TPO substrate are the most sensitive to thickness and wind speed while the asphalt is the least. In addition, thinning the substrate and increasing the wind speed could promote the net yield and CO2 emission reduction of the novel lightweight PV roof.