Multi-objective passive design and climate effects for office buildings integrating phase change material (PCM) in a cold region of China

Passive technologies integrating phase-change material (PCM) are effective means of enhancing energy flexibility and reducing carbon emissions in buildings. This research endeavors to conduct a life-cycle, multi-objective passive optimization for office buildings assembled with phase-change walls located in cold regions, considering both embodied and operational aspects. Dynamic simulations were used to assess two experimentally validated phase-change wall forms, considering criteria such as energy consumption, carbon emissions, and economic evaluation. Additionally, for future-oriented low-carbon buildings, it is crucial to determine the influence of climate change on the building ontology and PCM. The results indicate that the optimal configurations obtained through the sum-weighted approach can result in energy savings of >13 %, while simultaneously enhancing building performance and without any additional carbon emissions. Notably, the exterior PCM scenario notably exhibited superior energy savings compared to those of the interior scenario at an appropriate phase-transition temperature. Considering that over 68 % of a building's carbon emissions originate from operational factors, the conversion of the power mix to renewable sources under regulated climate change scenarios presents significant advantages for low-carbon buildings. The phase-transition period is projected to decrease by 11.6 % as a result of future climate effects. By means of the multi-objective optimization considering climate impacts, this study provides valuable guidance for the development of low-carbon office buildings. •A multi-objective optimization scheme integrating the PCM design parameters and building parameters was constructed.•The significance of phase-change walls in passive design had been determined for office buildings in cold regions.•The exterior PCM layer has more effective and can reduce the energy consumption of the building by 10.5 %.•Phase-transition period reduced by an average of 11.6 % in the climate scenarios.