Multi-objective optimisations of envelope components for a prefabricated house in six climate zones

The ever-increasing attention towards implementation of environmentally sustainable buildings necessitates the predictions of energy consumption and indoor environmental quality (IEQ) during early design stages. Prefabrication of buildings changes the construction process and components which affects building performance. Better understanding the effects of envelope components on energy performance and IEQ will inform design decisions leading to the creation of more sustainable buildings. In this article multi-objective optimisations of building envelope were carried out by coupling TRNSYS (Transient System Simulation Tool) and jEPlus + EA (EnergyPlus simulation manager for parametrics + Evolutionary Algorithms). The objective functions to be minimised were thermal discomfort hours (TDH), daylight unsatisfied hours (DUH) and life cycle costs (LCC) while maintaining acceptable sound transmission levels and indoor air quality. The decision variables were envelope components of a prefabricated house. Applications for six different climate zones corresponding to eight locations in Australia were investigated. The optimal solution sets were unique for each climate zone. The optimal solutions achieved 27–31% savings in LCC compared to the baseline. The reductions for TDH varied from 6% to 55% among the locations. As a result of trade-offs, the selected compromised solutions in each climate could achieve better reductions for either TDH, LCC or both