What is the optimal robust environmental and cost-effective solution for building renovation? Not the usual one

Abstract

Buildings are responsible for a large share of CO2 emissions in the world. Building renovation is crucial to decrease the environmental impact and meet the United Nations climate action goals. However, due to buildings’ long service lives, there are many uncertainties that might cause a deviation in the results of a predicted retrofit outcome. In this paper, we determine climate-friendly and cost-effective renovation scenarios for two typical buildings with low and high energy performance in Switzerland using a methodology of robust optmization. First, we create an integrated model for life cycle assessment (LCA) and life cycle cost analysis (LCCA). Second, we define possible renovation measures and possible levels of renovation. Third, we identify and describe the uncertain parameters related to the production, replacement and dismantling of building elements as well as the operational energy use in LCCA and LCA. Afterwards, we carry out a robust multi-objective optimization to identify optimal renovation solutions. The results show that the replacement of the heating system in the building retrofit process is crucial to decrease the environmental impact. They also show that for a building with already good energy performance, the investments are not paid off by the operational savings. The optimal solution for the building with low energy performance includes the building envelope renovation in combination with the heating system replacement. For both buildings, the optimal robust cost-effective and climate-friendly solution is different from the deep renovation practice promoted to decrease the energy consumption of a building.

Alina Galimshina

Postdoctoral researcher

Alina has joined the research group as a Postdoctoral researcher to work on environmental assessment of building-integrated photovoltaics and robust sustainable design strategies to improve the environmental performance of buildings. Her research areas are life cycle assessment, environmental building design, life cycle cost analysis, uncertainty quantification and global sensitivity analysis.

Alexander Hollberg

Associate Professor

Alexander Hollberg is Assistant Professor in the Division of Building Technology, at Chalmers.