Assessment of cost-benefit on ultra-low-energy building technologies application: a case study of public buildings in Xinxiang, China

Against the backdrop of global energy conservation and environmental protection, the importance of applying ultra-low-energy building technologies and evaluating their cost–benefit has become increasingly prominent. However, existing studies in evaluating the cost–benefit of these technologies are mostly limited to a single dimension. They overlook the interactions among economic, social, and environmental benefits. This study aims to effectively screen out technical combination schemes with better cost–benefit by sorting out the internal relationships among various factors of the cost–benefit of ultra-low-energy building technologies. To this end, this study constructs a life cycle-system dynamics analysis framework to comprehensively analyze the constituent elements and interaction mechanisms of incremental costs, economic benefits, as well as environmental and social benefits. Finally, a typical public building in Xinxiang City, China, is selected as a case study. Eight common ultra-low-energy building technical scenarios are set up, and a 20-year cost–benefit simulation is carried out. The research results show that among the eight proposed schemes, when the building envelope structure adopts the combination of an exterior wall (70 mm graphite polystyrene board) + roof (80 mm extruded polystyrene board) + exterior window (65 Series Vinyl Windows) + floor (70 mm extruded polystyrene board) and with a PV area of 150 m² reaches the optimal level of 8,748,300 yuan. This study provides a multi-dimensional evaluation model and a reference basis for optimizing the design of ultra-low-energy buildings, and effectively promotes the realization of the sustainable development goals of the construction industry.