A holistic environmental and economic design optimization of low carbon buildings considering climate change and confounding factors

The low carbon building design has become critical given the urgent need to reduce global carbon emissions. Reducing operational energy use through multi-objective optimizations used to be a common approach, but its validity is im-paired by surging embodied impacts. Therefore, a life cycle optimization becomes necessary to improve the overall carbon performance of buildings. However, current research lacks an application of multi-objective optimizations to explore the energy use, carbon emission and cost considering both embodied and operational impacts. Impacts of con-founding design factors and climate change on achieving low carbon designs are also not sufficiently revealed by existing studies. To address these gaps, this study: (i) proposes a parametric design optimization method for low carbon buildings considering cost-effectiveness, (ii) explores the impacts of confounding factors on achieving low carbon de-signs and (iii) evaluates the impact of climate change on the life cycle performance of buildings with proper scenario assumptions. A case study is conducted to explore passive design parameters and integrated photovoltaic (PV) appli-cations to reduce the energy use and carbon emissions in a cost-effective approach. The joint optimization of embodied and operational impacts can reduce the energy use, carbon emission and cost by 42%, 58% and 32%, respectively. Also, variation of confounding factors can lead to different optimized designs with carbon reduction difference up to 75%. The results also show that global warming will lead to higher energy use and carbon emissions in tropical re-gions within the near future, while stringent mitigation strategies aligned with RCP 2.6 can reverse the trend after two decades.