The impact of courtyard layout on outdoor thermal comfort: a parametric study in mid-rise residential buildings in Shiraz city

Courtyards have had various architectural functions, which have maintained their effectiveness. The appropriate placement of courtyards in the design of residential buildings, is important in many ways, especially the level of outdoor thermal comfort of spaces. Despite the increasing warnings about the problem of global warming and the need to use appropriate urban forms and architecture, many designers do not have sufficient awareness of this issue. To fill this gap, this research, using a post-positivist paradigm and a combination of simulation and logical reasoning strategies, examined the optimal placement of courtyards in one- to seven-story residential buildings in Shiraz with a parametric approach. The main hypothesis of this research was that the use of optimal courtyard patterns in building design can increase the percentage of hours of thermal comfort in outdoor spaces. The variables were the possible sizes of the yard along the X axis, which determines the length and width of the yard, the displacement modes of the yard along the X axis, the displacement modes of the yard along the Y axis, the angle of buildings relative to the east-west axis, the number of floors, and the percentage of hours that the yard and pedestrian are in the thermal comfort zone. A computer simulation was used to analyze the relationships between the research variables. The simulations of this research were conducted using the Ladybug tools. The final data analysis and the analysis of the results were performed using the logical reasoning method. Information was collected through library studies, information available on the Internet, and computer outputs. To make the research results usable, the dimensions of the reference model were selected from the approximate average of the residential block plots in the study area. To conduct the computational simulations, in the first stage, a parametric process of generating different types of courtyards was carried out, using Rhino software and the Grasshopper plugin. In the second stage, using the Ladybug tools and Universal Thermal Comfort index, the microclimatic performance of models was investigated concerning the variables and the desired objective function, compared with the current situation, and optimal options were introduced using the Octopus multi-objective optimization plugin. After data analysis, the obtained results confirmed that the appropriate placement of the courtyard on the ground, considering its microclimatic effects, can have a positive effect on the thermal comfort of users in open spaces. A comparison of the microclimatic performance of two- to seven-story buildings showed that when the courtyard of the building is placed in the middle, in a way that divides the building into two parts, the percentage of hours that both the courtyard and pedestrian areas remain within the thermal comfort range throughout the year will increase. In one-story buildings, due to the low height of the building, the presence of a central courtyard does not play a positive role in increasing the percentage of hours that both the courtyard and pedestrian remain in the thermal comfort range throughout the year.