Retrofitting existing office buildings towards life-cycle net-zero energy and carbon

Background: Energy devices for achieving net-zero operating energy and carbon generally entails additional embodied energy and carbon during the production and disposal stages. For a building to be considered as truly life-cycle net-zero, the energy use or greenhouse gas emissions occurring across each stage of its life span must be offset. Retrofitting design approach for strict life-cycle net-zero buildings is still quite rare. Method and innovation: The innovation of this study is to propose an integrated design process to determine optimal retrofitting solutions and achieve life-cycle net-zero. The retrofitting also aims at maximising lifetime payback cost by selecting appropriate installation areas or capacities of each renewable energy device. A realworld office building is adopted as a case study to demonstrate the proposed retrofitting design approach, while 5 different sceneries are adopted to demonstrate different retrofitting situations. Results and implication: The maximum lifetime payback cost reduction would be 116.3% and 103.5% for life-cycle net-zero energy and carbon for this case study building. The proposed integrated design process can be applied to different types of buildings to transform them into truly carbon-neutral and consequently mitigate climate change-related issues.