Energy-Saving and Decarbonization Design Optimization for School Canteen Buildings: A Case Study in Nanjing

In light of global climate change and China's commitment to carbon neutrality by 2060, this study explores energy-saving and decarbonization design optimization for educational buildings, with a specific focus on a high school canteen in Nanjing. Through a comparative analysis of optimal energy-saving and lifecycle decarbonization retrofit schemes, the study aims to identify the performance differences and provide practical guidance for retrofitting educational buildings. The optimization process involves two separate single-objective optimizations: one aimed at minimizing annual total primary energy consumption (TES) and the other at minimizing lifecycle carbon emissions (E). Energy performance is simulated using EnergyPlus 23.1.0, while the Strengthened Elitist Genetic Algorithm (SEGA) is applied to optimize design variables such as insulation materials, window types, window-to-wall ratios (WWRs), and photovoltaic (PV) system configurations. The results reveal that the optimal energy-saving scheme achieves zero net energy consumption annually, generating a surplus of 20,625.2 kWh (15.05 kWh/m2). Conversely, the optimal decarbonization scheme achieves zero lifecycle carbon emissions, contributing a carbon reduction of 386,926.4 kg, albeit with a 28.83% higher lifecycle TES compared to the energy-saving scheme. This study underscores the distinctions between energy-saving and decarbonization retrofits and offers valuable insights for sustainable retrofitting of educational buildings in China.