Development of rooftop photovoltaic models to support urban building energy modeling

Developing the rooftop photovoltaic (PV) system was beneficial to generate electricity and reduce carbon emissions in buildings. This paper presented the rooftop PV modeling method to support urban building energy modeling (UBEM) using the prototype UBEM method and the building-by-building UBEM method. The PV modeling method was developed, which was capable for buildings with rectangular flat rooftops, pitched rooftops, and arbitrary-shape flat rooftops. The main layout configuration parameters of the rooftop PV can be customized, including the PV dimension, tilt angle, azimuth angle, number of stacked rows, and the interrow spacing of panels. A district in Changsha, China, was selected as the case study, where basic building information was collected, including the building type, building footprint, year built, and the number of stories. The results showed that the PV models can be successfully added to all 5717 buildings with arbitrary-shape flat rooftops through manual inspection. When the interrow spacing was larger than 1 m, with the decrease of interrow spacing, the power generation increased because of the larger PV installation area, even if the self-shading impact increased. The largest PV power generation was 110.81 kWh/m² and 94.00 kWh/m² per roof area in Changsha when using the prototype UBEM method and the building-by-building UBEM method. The power generation using the building-by-building UBEM method was 15.17 % less than using the prototype UBEM method because the power generation due to shading from surrounding buildings decreased by 5.57 %, and the PV installation area decreased by 10.00 %.