Exploring influences of rural morphology on building cluster energy consumption and retrofit performance: A case study of Nanjing, China

Abstract

Rural building retrofit plays a pivotal role in achieving national energy goals and enhancing residential well-being. However, due to the neglect of village morphology, its progress and effectiveness are impeded. To address this issue, this study examined 300 rural building groups, including traditional and non-traditional villages in Nanjing, China. Combining URBANopt SDK with a SHAP value-based machine learning model, we quantified the impact of rural morphology on building cluster energy use intensity (EUI) and retrofit performance for the first time. Furthermore, to account for rising energy demands in rural regions, a high-intensity energy use pattern was introduced to evaluate the long-term dynamics of morphological effects. The results show that average building footprint area (BFPA) is the most influential morphology. As BFPA increases from 50 to 100 m², cluster EUI declines linearly. Roof insulation proved the most effective retrofit measure, yielding EUI savings exceeding 6 % and 10 % in current and future scenarios, respectively. With rising energy demand, morphological influences intensify: the EUI gap between clusters with minimum and maximum BFPAs widened to 14.6 %, while energy-saving rates for all measures nearly doubled. These findings highlight the necessity to incorporate rural morphology into building energy retrofit, particularly in a future of growing energy demand.