الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 174 |  |  |
| | | from | 174 | | |
Abstract
This dissertation presents the result of an experimental/computational study of the combined effects of external environment and opening in natural ventilation and thermal comfort in buildings. The investigation was carried out on three different stages where two different building models were investigated. One model (denoted M1) represented an open space in a typical commercial building (i.g. an office building) with multiple and identical front and rear openings. The other model (denoted M2) represented a room in a typical residential building with a signal opening in each of the front and rear walls. In the first stage, both models were subjected to a series of tests using a smoke tunnel test facility in with a view to evaluate the effect of wind orientation and opening location and combination on the flow pattern inside the ventilated space. Although pictures of such flow patterns gave only a qualitative evaluation, they were quite useful in understanding and interpreting of the experimental findings from wind tunnel measurements.
In the second stage, measurements were taken in a wind tunnel inside which turbulent wind was simulated (wind simulator). This tunnel test facility was designed and constructed with local materials and know how. Suitability of this wind simulator for the purpose of the present work was first checked through extensive testing before carrying out the main investigation on building models.This investigation consisted of two parts. The first part was concerned with tests on model M1 for the effect of the window combination and arrangement on thermal comfort in the ventilated space under different external environmental conditions and fixed thermal load. In the second part, model M2 was subjected to a series of tests in which pressure distributions on exposed surfaces (front, rear, side walls, and window zone) were obtained for different external environmental conditions.
Here also thermal comfort characteristics of the ventilated space were examined for different window sizes and locations. For both models, single-sided and cross ventilation schemes were considered. Results indicated substantial effects of the external environmental conditions, window size and combination on thermal comfort level.
In the third stage of the work, a CFD-based software package (ANSYS FLOTRAN version)was applied to the present problem, where the above effects were predicted and compared with experiment. Comparisons showed good agreements, including that CFD techniques such used by ANSYS (finite element technique) can be reliably used in this type of problems. Also, comparison indicated that the experimentally-obtained results can be3e accepted with confidence, leading to solid conclusions. The present work gives important recommendations to architects and designers of new buildings with regard to combination, location and size of the openings in building front and rear facades for the best possible thermal comfort, depending on prevailing wind conditions and building orientation. Thermal comfort in an existing building, subject to analysis, may be improved through certain combinations of openings or by changing window size and location of allowed. Such improvement would be limited by the permissible changes and the prevailing wind characteristics. A thermal comfort chart derived in the present work should be quite useful both for designers and.
Finally, CFD techniques can be prove economical in problems of building thermal comfort, saving time and cost spent in experimental efforts, especially if all possible conditions are to be studied.