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Assessing the urban-scale building photovoltaic (PV) potential is important for designing urban environments, retrofitting existing structures, or integrating PVs with grids. However, few studies have considered high-temporal-resolution simulations, the facade PV potential, and a comprehensive PV model simultaneously; thus, the overall accuracy of the estimation of PV potential may be limited. Therefore, this study developed an integrated framework to assess the urban-scale PV potential of rooftops and facades at high spatiotemporal resolution. The proposed approach integrates an anisotropic sky diffuse model, a vector-based shading calculation method, and a temperature-related PV performance model. The annual PV potential and spatial/temporal characteristics were analyzed in a case study of over 170,000 buildings in Beijing. The results showed that the estimated rooftop PV power generation was 7.55 TWh/y, whereas the facade PV power generation was 18.07 TWh/y, which was 239% of the rooftop PV yield. The integrated model estimated PV yield with higher accuracy than the simplified models by depicting more details. The proposed approach can be applied to the large-scale assessment of future energy systems with increasing penetration of PVs, and the results can support effective policies for the integration of PVs into the built environment in dense cities. [Display omitted] • High-accuracy models of sky diffusion, shading, and PV performance were integrated. • Facade PV potential was equivalent to 239% of the rooftop PV potential in Beijing. • Shading affects less on rooftops, but reduces up to 15% of facade PV yield in blocks. • PV potential on facades is greater downtown than in suburbs, while similar on roofs. [ABSTRACT FROM AUTHOR]

Understanding the demand flexibility of city-scale buildings under different demand response (DR) strategies is crucial to balance the power supply and demand in the grid. This paper presented a case study to evaluate the electricity consumption reduction potential for buildings in Changsha under different DR strategies. First, sixty-six prototype energy models for twenty-two building types of three vintages were selected to represent 59,332 buildings in Changsha. The total electricity consumption of the building stock was obtained by aggregating the prototype electricity use intensity with their representative building area. Three DR strategies were formulated, including temperature reset, lighting control, and plug load control. Second, a toolkit, AutoBPS-DR, was developed to automatically integrate individual DR strategy as well as their combination into the baseline energy models. Five scenarios were analyzed, including the baseline case, three cases with a single DR strategy, and a case with three DR strategies combined. The results showed that compared to the baseline scenario, the electricity consumption reductions of the case buildings for a 3-h DR event under temperature reset, lighting control, plug load control, and combined control scenarios were 603.97 MWh (7.94%), 441.08 MWh (5.80%), 663.26 MWh (8.72%) and 1673.32 MWh (22.00%), respectively. In the plug load control scenarios, high-rise apartments made the largest contribution with a reduction of 134.15 MWh. Medium office buildings had the most reduction under the other three scenarios, with a reduction of 122.16 MWh for temperature reset, 107.90 MWh for lighting control, and 357.16 MWh for combination control. This study demonstrated a significant DR potential for buildings in Changsha to overcome the electricity shortage period. [ABSTRACT FROM AUTHOR]

[Display omitted] • Presented a novel co-simulation framework for ground-coupled building envelopes. • Developed an XGB-based regression model for heat responses over various buildings. • Derived the theoretical thermal process solutions for equivalent slabs. • Integrated the underground heat transfer model into the building simulation engines. • Validated the modeling accuracy and computational efficiency of the proposed method. Ground-coupled building envelopes contribute to up to 45% of total building heat loss. Dynamic simulation of the thermal process of the building-ground structure is essential for whole-year building energy simulations and evaluations. There exist various types of underground heat transfer models, while the adoption of dynamic underground heat transfer models in building energy simulation software is quite limited because of accuracy or computational efficiency issues. To fill this gap, this research proposes a novel co-simulation framework for dynamic underground heat transfer with building energy models. An XGB regression model was developed for the calculation of the heat response coefficient of building-ground structures, based on which an equivalent slab model is proposed and integrated with the general building energy models. The proposed co-simulation model was validated using the detailed 3-dimensional finite difference method. It can be concluded from the validation results that the simulation errors of the inner surface temperature of ground-coupled envelopes do not exceed 0.6℃, while the computational speed is improved by 4000–20000 times. The proposed model was integrated into the building performance simulation software DeST for the whole-year dynamic simulation of building-ground structures. [ABSTRACT FROM AUTHOR]