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Energy and the Environment, 1999

ISSN:
1-56700-127-0 (Print)

INVESTIGATION OF AIR FLOW PATTERNS OF EXTENDED SOLAR WALL AND ROOF CHIMNEYS IN HOT-ARID CLIMATES

Mohsen M. AboulNaga
Department of Architectural Engineering, UAE University, P. O. Box 17555, Al-Ain, UAE

Abdullatif M. Alteraifi
Department of Mechanical Engineering Faculty of Engineering, UAE University, P. O. Box 17555, Al-Ain, UAE

Abstract

This paper investigates air flow patterns and behavior in an extended solar wall-roof chimney incorporated into a typical room with an inlet and outlet. In addition, the results of the extended solar wall-roof chimneys are compared with that of the solar roof chimney alone. Numerical simulations using the Fluid Dynamics Package, FIDAP, are exploited to describe and analyze the air flow patterns inside the room, and in the extended solar wall-roof chimneys. FIDAP simulation analyses and results of the air flow streamlines, velocity vectors, and temperature distributions are presented. At 0.25m separation, in both wall and roof solar chimneys, the maximum chimney outlet flow rate and smooth streamline were found when the wall chimney is 2.00m high, which corresponds to a wall chimney inlet of 1.60m. Results show that the maximum relative speed in the combined chimneys is higher than the solar roof chimney alone. These findings suggest that the exploitation of an extended solar roof-wall chimney could enhance night-time natural ventilation and the cooling of buildings. The system is limited to cool low-rise buildings in hot-arid regions such as Al-Ain city, UAE, where energy use is enormous.