Leila Sriti

Envelope Building materials play an important role in architecture by providing protection necessities, comfort, and technical performance while promoting an architectural language and an image. The building envelope represents all the surfaces of a space, consist of opaque parts such as walls, floors and roofs and transparent parts such as windows and openings. The building envelope is the partition between the external and internal environment of the building influences heat transfer between two environments so it has a direct impact on the thermal comfort sensation which also influences the energy consumptions. In this research we focus on the opaque building materials of the envelope and their contribution in the thermal comfort and the energy consumption, we investigate the impact and the thermal behavior of different envelope configuration materials under the climatic conditions of Biskra, Algeria a hot and arid climate. We compare the thermal performance of different materials using in situ measurement using “Testo 480” a hygrothermal scale and by analyzing the results of a different simulation using “DesignBuilder v5.5” to perform a thermal and energy analysis. Choosing a multilayered isolated envelope such as double red brick isolated wall will likely affect positively the level of the indoor thermal comfort.

The Uncontrolled urban sprawl and the unadopted building to the environment are the main causes that generate the urban heat island (UHI) phenomenon. This phenomenon contributes to the degradation of the environmental quality of the interior and exterior spaces and increases the energy demand of buildings. In hot and arid regions, the cooling needs of space during the hot season are much greater. This situation imposes the use of electrical air-conditioning equipment for longer periods, which leads to a drastic consumption of electrical energy, implicitly, rise the greenhouse gas emissions, which in turn accentuate the phenomenon of the urban heat island. In this context, one of the most effective strategies to moderate heat stress at the urban scale is the adoption of the cooling roof technique "cool roof”. In fact, solar reflectivity (SR) and high emissivity (IE) of cool materials allow them to absorb less solar energy than conventional concrete roofs, reducing the amount of heat transferred to the atmosphere. This research aims to evaluate the impact of cool roof on the mitigation of the urban heat island phenomenon and to investigate its effect on reduction of energy consumption. Experimental work was carried out in Biskra hot and arid climate.