The effects of the layouts of vegetation and wind flow in an apartment housing complex to mitigate outdoor microclimate air temperature

Abstract

Previous studies have demonstrated that vegetation and increased air flow can mitigate air temperature by employing numerical models, satellite remote sensing or Computational Fluid Dynamics simulations. This study aimed to examine how layouts of vegetation space and wind flow affect microclimate air temperature, which directly affects city dwellers' thermal comfort in summer, in a real apartment housing complex in Seoul, South Korea. To do this, a Reynolds-averaged Navier-Stokes model was utilized, combined with a finite volume method CFD simulation, and which measured transpirational cooling effects of vegetation by comprehensively considering air humidity by transpiration, as well as wind flow of the surroundings, to reflect actual conditions of urban environments. Based on the computational model, nine scenarios including elevated building designs were simulated. The findings of this study are as follows: First, different layouts of vegetation and wind flow clearly affected microclimate air temperature in the housing complex. Second, when the total area of vegetation was the same, it was more effective to reduce air temperature by placing it in small units rather than concentrating it in one place, and placing small vegetation spaces close to buildings was better than locating them between buildings. Third, it was apparent that an elevated space works as a wind path, leading to increasing wind velocity. However, it was revealed that wind flow does not always positively affect hot temperatures.