Use of cool materials and other bioclimatic interventions in outdoor places in order to mitigate the urban heat island in a medium size city in Greece

Abstract The materials that are used in outdoor spaces are of prime importance as they modulate the air temperature of the lowest layers of the urban canopy layer, they are central to the energy balance of the surface and they form the energy exchanges that affect the comfort conditions of city people. Paved surfaces contribute to sunlight's heating of the air near the surface. Their ability to absorb, store and emit radiant energy has a substantial affect on urban microclimate. The thermal behaviour of typical construction materials in an urban center of North Greece, at Serres, was investigated. The thermal fluctuation during the day and the surface temperature differences between different materials in a selected area inside the urban centre of the city was monitored. The replacement of conventional materials with cool materials was evaluated to have significant benefits. CFD simulations showed that materials replacement, accompanied by other mitigation techniques in the area, result at reduction of the mean surface temperature in the streets of the area of 6.5 °C. The results of the measurements and the CFD simulations are presented in the paper.