Optimization research on energy-saving and life-cycle decarbonization retrofitting of existing school buildings: A case study of a school in Nanjing

Abstract

Given the continuous urbanization, many old buildings urgently need retrofitting. Considering the impact on student health, carbon peaking and carbon neutrality policies, the retrofitting of school buildings has become a focus for researchers. This paper presents a complete optimization method for energy-saving and life-cycle decarbonization retrofitting of existing school buildings. Through this method, a target building is first evaluated from three aspects: envelope, energy system and occupation information, and the weak links of the retrofit project are analyzed through combining measurement and simulation. The study describes the evaluation indicators of two optimization objectives (energy-saving and life-cycle decarbonization) and analyzes the constraints and optimization variables in the retrofit from the aspects of site layout, geometry, structure, envelope and energy system. Consequently, an efficient optimization method is introduced. The proposed method is applied to a school retrofit case in Nanjing, China. The results show that through the optimization of energy-saving, the retrofitted school can produce 102,786 kWh (14.36 kwh/m2) of excess renewable power per year. Upon applying the life-cycle decarbonization optimization, the retrofitted school can achieve zero carbon emissions throughout its life cycle and save 1,920,853.3 kg of carbon emissions in the region.