Optimizing urban courtyard form through the coupling of outdoor zonal approach and building energy modeling

Abstract

Urban courtyards are well known for their potential thermal performances in vernacular urban morphology. Furthermore, in a more general approach considering various cities and locations, new building uses, and climate changes, a correct courtyard design requires an accurate understanding of the complex interactions between buildings and their surroundings. This study aims to develop tools and processes to optimize the design of these urban courtyards. A microclimate model is developed and integrated in a building simulation software (TRNSYS) to evaluate the thermal microclimatic conditions of courtyard building, and their heating and cooling energy demand. A specific zonal model is developed for the local courtyard microclimate, which is coupled with a previously developed thermoradiative model. Indoor conditions are modeled by the multizone building model of TRNSYS. This methodology is used to investigate the microclimatic influence of different courtyard morphology on their thermal behavior in three different climates (hot, temperate and cold). An extended study on the impact of courtyard aspect ratios has been carried out. In order to optimize the courtyard heating and cooling energy needs, a multiple regression analysis was further used to develop the fast prediction model and then select the non-dominated solutions using pareto efficiency. The results suggest optimal morphology in order to enhance the energy performance of the courtyard, from which square shape is more advantageous in cold climates (reduced heating energy needs by approximately 48%), while the deep and less wide shape is more advantageous for hot and arid climates (reduced the cooling energy needs by about 10%). For temperate climate, the shape guaranteeing minimum energy needs and, in all seasons, is the one with less width and medium depth (allowing a reduction in energy needs of about 58%).