Thermal perception in outdoor urban spaces under the Mediterranean climate of Annaba, Algeria

Abstract

Many studies were investigated to grade outdoor thermal comfort and related thermal sensation during the past years. This study aims to explore thermal comfort conditions and thermal sensation in the hot Mediterranean climate (Csa), which annually includes 1100–1700 cooling degree days and 1200–1800 heating degree days (CDD = 1100–1700, HDD = 1200–1800). This research tested the human thermal sensation by applying the Physiological Equivalent Temperature (PET) index. A field survey of 1230 interviewees was conducted in Annaba, Algeria, in four outdoor environments having the same morphology and different green cover. The scientific method involved combining two software. Envi-met was used to calibrate microclimatic data (air temperature, wind velocity, relative humidity and mean radiant temperature); in comparison, RayMan used to calculate PET. The results showed the neutral sensation range for this Mediterranean climate varies between 20 °C and 26 °C. The highest scores of neutral thermal sensation were recorded in spaces with vegetation cover, which involves the trees cooling effect in enhancing thermal comfort, especially during the hot hours of the day. The air temperature divergence reached 4 °C and 3 °C for Tmrt at noon, considered the day's hottest hour. The findings also highlight the existence of a thermal adaptation in outdoor spaces having a green cover.