Investigation of the thermal environment in schoolyards under Mediterranean conditions. Contribution to bioclimatic conditions improvement with the application of mild interventions – The case study of a school within the urban environment

This study aimed to examine the thermal environment in schoolyards under Mediterranean conditions, and the impact of two interventions on the amelioration on the bioclimatic conditions. The investigation was performed for three schools in Athens, Greece, through microclimatic simulations by ENVI-met, for a typical day in June, and was evaluated based on the air and surface temperature values. The bioclimatic index Physiological Equivalent Temperature (PET) was applied to evaluate the thermal comfort conditions. By that, the school under the most adverse thermal conditions was selected for the application of two interventions, which increased the greenery by 25% (Proposal 1) and 50% (Proposal 2). The surface coating material “safety floor slabs”, was selected to replace the others in both proposals. Through microclimatic simulations, the following results were obtained: “Proposal 1” caused a 2.3°C reduction in surface temperature, and a 4% reduction in PET values. ‘Proposal 2’ caused an 8.1°C reduction in surface temperature, and an 11% reduction in PET values. The cooling effect of ‘Proposal 2’ was double compared to ‘Proposal 1’, achieving a maximum air temperature reduction by up to 0.8°C. The cooling effect produced was limited to the areas affected by tree shade, leaving the unshaded areas almost unaffected.