Energy performance of building envelope in Egypt

الملخص EN

The incremental growth in the demand for energy consumption, especially in buildings, leads to a considerable problem that most of developing countries have faced during the last few years.

This study investigates theoretically and experimentally the effect of modern technology used by the building envelope on energy conservation in the building sector under the effect of 3 different climatic conditions in Egypt : Alexandria, Cairo and Aswan.

These represent the climates of the Mediterranean Sea, the hot-dry and the very hot-dry regions respectively.

The development of building technology during the19th and 20th centuries is discussed to determine the effect of external envelope technology on energy conservation in buildings.

Principles of energy conservation and different theoretical methods for evaluation of thermal performance of building envelope were examined through this study.

The effects of orientation, building shape, window to wall ratio, glazing type and building materials on thermal performance were discussed.

Also the study takes into consideration the different strategies used in different climatic zones, especially the hot-dry zone.

A new technique called overall thermal transfer value OTTV was developed and used to evaluate the efficiency of the building envelope in the case of conditioned buildings.

The results of this investigation show that for the development of building energy technology and the emerging new trends, it is essentiality to take into consideration thermal performance efficiency and the compatibility of the building with the environment.

Our study showed that from the calculation of the overall thermal transfer value we can evaluate the energy performance of buildings.

Thermal factors requirements for designing and constructing the external envelope for conditioned and unconditioned buildings are orientation, R-value, shading factor and solar heat gain.