Abstract
In northern Algeria, use of ventilation by ceiling fans is widespread in mosques and other public buildings during the hot season, but is seldom used in private houses. In the first part of this study, the impact of this mode of cooling on indoor thermal comfort is investigated. A thermal comfort model for transient conditions is developed in order to calculate an instantaneous thermal comfort index. In order to simulate the thermal behaviour of a human body as accurately as possible, the latter is divided into 17 segments and a heat balance equation is written for each segment. The results indicate that even during hot days, an appreciable thermal comfort can be achieved if ventilation at constant air speed is used. Moreover, it is shown that it is not necessary to increase ventilation speed beyond a given level, as thermal comfort gains become negligible.
In the second part of the study, the impact of solar radiation on thermal comfort is evaluated. Thermal sensation of a human being partially exposed to direct solar radiation is calculated. The results show that a discomfort sensation is quickly felt when a person is exposed to sun fluxes, which confirms the importance of shading devices.