The feasibility of passive downdraught evaporative cooling for high-rise office buildings in Cairo

This article reports on the initial findings of an ongoing study investigating the application of passive downdraught evaporative cooling (PDEC) to high-rise office buildings in Cairo. Two climate analysis methods are utilized to assess the suitability of PDEC to Cairo's climate. The first makes use of Givoni's building bio-climatic charts (BBCCs) while the second adapts the climate suitability analysis method (CSAM) initially developed to assess the potential of a given location for direct ventilative cooling to work with PDEC. PDEC is not a strategy that can readily be incorporated into buildings. The task is even more onerous if tall buildings are involved. The article discusses the means of configuring the high-rise office building to incorporate PDEC along with complementary passive cooling strategies such as night ventilation. A preliminary dynamic thermal simulation is performed on a developed model of the PDEC high-rise office building. The results of the dynamic thermal simulation confirm the validity of the two climate analysis methods but indicate that the effectiveness of PDEC at maintaining thermal comfort is largely dependent on the chosen definition of acceptable comfort conditions. Finally, the validity of the adaptive comfort model in predicting comfort conditions in PDEC buildings is discussed.