Geometry optimization in the schematic design phase of low-energy buildings for all European climates through genetic algorithms

Abstract

The ongoing transition towards resilient and energy-efficient cities highlights the design of new buildings as a critical concern. With the increasing urbanization in Europe and the concurrent need for energy reduction and decarbonization, it is crucial to address energy efficiency in the construction sector, as by the recently adopted European Energy Performance of Building Directive. In this context, the article focuses on the role of geometry optimization in the schematic design phase of low-energy buildings, by considering it among different European climates. Indeed, this study aims to propose a multi-objective optimization approach (using a genetic algorithm) to optimize the “genes” of the building, e.g., shape, proportions, orientation and window-to-wall ratio of residential buildings in the early design phase, to cut off a significant portion of energy consumptions. The objective is thus to minimize heating and cooling energy needs based on the best combination of the above-mentioned genes. The research investigates optimal solutions across various European climates based on the Köppen-Geiger classification, comparing the results for 19 European cities with varying climate. The findings confirm that the energy needs of buildings are strongly influenced by the climate conditions of their location. The study, which comprehends almost 250.00 different configurations, assesses, as expected, the strong effect of climate conditions on the energy needs and highlights the cross-shaped buildings as the best performing in 17 over 19 sites investigated. The optimal solution for each site leads to total energy needs that are comprised between 4.58 kWh m-2 y-1 in Porto and 19.84 kWh m-2 y-1 in Goteborg, with an average across all cities of 12.45 kWh m-2 y-1. The research provides valuable insights for professional in the construction sector, aiding them in making informed decisions during the schematic design phase to achieve low-energy buildings that are adapted to specific climates.