Environment

PHD

A.M. el Zafarany: Dome Research1

Contents

Home

 

Ahmed Ahmed Fekry,Ph.D

Abbas M. el-Zafarany,Ph.D

Associate Professor, Faculty of Engineering,
Cairo University

Lecturer, Faculty of Regional & Urban Planning, Cairo University

 

Summary

This Paper presents a highly selective method for shading east and west windows using inclined sun breakers.

Solar Gain represents increases the cooling loads, and causes discomfort in passively cooled buildings, but solar gain is to reduce winter heating loads.

A selective shading device is the one able to pass the required solar radiation and prevents the undesired radiation.

Sun breaker is a selective shading device, The horizontal overhang used in the southern facades is well known for its selectivity, it passes law altitude winter radiation, while preventing high altitude summer radiation.

Same selectivity is not achievable in east and west facades using typically recommended vertical sun breakers, unless they are operable, achieving selectivity by moving fins.

Using a software for visualizing solar movement, south overhang looks parallel to the solar path as seen from south window, which is almost horizontal.

Applying the same concept, brought up the Idea that breakers in the west and east  walls should be parallel to solar path as seen from these facades, introducing a type of Inclined sun breakers that challenges the limitations of horizontal and vertical fins.

In Cairo for example (30 N latitude) the solar Path appears as a series of lines inclined by 60 that was the direction selected for sun breakers.

A special software was developed to evaluate performance of such technique quantitatively, and comparing it with other shading devices, this software is capable of modeling complicated traditional shading devices such as Arabesque (masharbeya) and Gypsum decorative screens.

Its results were verified by comparing shadow patterns with a physical Model for the recommended solution. This has shown that a sun breaker Inclined by 60 gives the best performance on west and south walls in Cairo. The rotation of fins about its axis should be 50 downwards.

 

Environment

PHD

A.M. el Zafarany: Dome Research1

Contents

Home