A Coordinated Envelope–HVAC Optimization Framework and Service-Life Cost Assessment for Temporary Container Buildings

Temporary container buildings are widely used because of their rapid construction, flexible deployment, and suitability for construction-site accommodation, emergency facilities, event housing, and other short-term scenarios. However, their energy-saving design still lacks specialized standards. Key parameters such as insulation thickness, window thermal performance, airtightness, and split-air-conditioner efficiency are often selected empirically, which makes it difficult to balance initial investment and operating cost over the actual service life. To address these issues, this study proposes a service-life cost-based coordinated optimization framework. The framework couples DeST hourly load simulation, a TRNSYS-derived dynamic energy-efficiency-ratio (EER) model for split-type air conditioners, an economic model including initial investment and electricity operating cost, and an SLSQP-based optimizer. Field measurements from a three-story container dormitory in Haidian District, Beijing, collected in August and December 2023, are used to validate the HVAC electricity-consumption model through cumulative electricity-consumption errors and CV(RMSE). Using a south-facing single container building in Beijing as the base case, optimization is conducted for design service lives of 1–10 years and further compared under different electricity-pricing models and climate regions. The results show that, within the allowable parameter ranges, the proposed method can reduce service-life cost by up to approximately 32%. In the Beijing 2-year case, the optimized scheme reduces service-life cost by 39.9% compared with the permanent-building-code benchmark and by 11.4% compared with a market sample. The results demonstrate that coordinated envelope–HVAC optimization can avoid redundant initial investment and provide scenario-adaptable design support for temporary container buildings.