Environmental and economic optimisation of buildings for different climates

Introduction: Life Cycle Assessment (LCA) is a scientific method for evaluating the environmental impact of products. Standards provide a general framework for conducting an LCA study and calculation rules specifically for buildings. A challenge is to design energy efficient buildings that have a low environmental impact, reasonable costs, and provide high thermal comfort, as these are usually conflicting aspects. Efficient mathematical optimisation algorithms can be applied to such engineering problems. Methodology: In this paper, a multiobjective optimisation technique, the Direct MultiSearch method, is described and its applicability is tested on a multi-story residential building’s case study for two locations, Portugal and Hungary. The objectives are to minimise the life cycle environmental impacts and costs. Results and conclusions: The results indicate that optimum solutions are found at a higher cost but lower Global Warming Potential for Portugal than for Hungary. Optimum solutions have walls with a thermal transmittance of about 0.23 and 0.15 W/m2K for Portugal and Hungary, respectively. Multi-objective optimisation algorithms can be successfully applied to find solutions with low environmental impact and eco-efficient thermal envelope.