OPTIMIZATION OF AN ENERGY EFFICIENT OFFICE BUILDING IN SUBTROPICAL BRAZIL

Resumo

Energy policies have been developed to reduce buildings’ impacts on climate change. As they require quantifying energy use, simulation tools can help designers in the decision process. There are several variables to be considered in early stage building design. By coupling building performance simulation with optimization methods, the designer can analyze multiple solutions and avoid excessive calculations. This paper applied a multi-objective genetic algorithm to find optimum solutions for a case study medium-rise office building in São Paulo – Brazil using passive design strategies to minimize initial construction cost and life-cycle energy cost. The method coupled EnergyPlus simulation software with the jEPlus+EA interface to run the optimization. 213 cases were simulated with five design variables: orientation, window-to-wall ratio, wall type, roof type and glazing type. The results were presented through a Pareto optimum front, with seven non-dominated solutions, grouped into two distinct clusters. An initial construction cost reduction of 6.7% was observed in one cluster’s optimal solution, when compared to the base case. In the other cluster, another optimal solution presented a decrease of 5.8% in the life-cycle energy cost from the base model. The design parameters recommended for a medium-rise office building in São Paulo from this multi-objective optimization include small window-to-wall ratio, insulated flat roofs and laminated glazing with low solar heat gain coefficient. The proposed method can be further developed for more complex building shapes and include thermal comfort and environmental impacts criteria.