Abstract
The energy requirement for cooling residential and industrial buildings in the summertime is extensive, especially in hot weather countries. Solar energy contributes substantially to the cooling load. The solar intensity is usually high and can be about a kW/m2. Besides, the cooling period or comfort conditions in those countries exceed 5 months and outdoor temperature can reach more than 40°C. Any attempt to reduce the effect of solar energy on the cooling load is worthy of investigation. The present work analyzes using artificial, naturally ventilated, shading covers to reduce the effect of solar energy. A computational fluid dynamics approach is used to understand the physics of natural convection between an exterior wall of a building and an artificial shade. Since the building is air conditioned, it is expected that the exterior wall temperature may be less than the ambient temperature of a shaded wall. Hence, the analysis covered a wide range of rate of cooling of the exterior wall and assumed that the shading material is always at a higher temperature than the ambient due to solar energy.
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Abbreviations
- H :
-
Channel length
- g :
-
Gravitational acceleration
- h :
-
Wall heat transfer coefficient
- k :
-
Fluid thermal conductivity
- L :
-
Spacing between walls
- N :
-
Cooling rate = (T w − T a)/(T s − T a)
- Nu :
-
Nusselt number
- P :
-
Dimensionless pressure
- Pr :
-
Prandtl number
- Ra :
-
Rayleigh number
- T :
-
Temperature
- U :
-
Dimensionless transverse velocity
- V :
-
Dimensionless streamwise velocity
- X :
-
Dimensionless transverse coordinate
- Y :
-
Dimensionless axial coordinate
- θ :
-
Dimensionless temperature, (T − T a)/(T s − T a)
- ν :
-
Kinetic viscosity
- a:
-
Ambient air
- av:
-
Average
- s :
-
Hot wall
- w:
-
Cold wall
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Mohamad, A.A., Alansary, H. & Orfi, J. Natural Convection Between a Vertical Wall Exposed to Solar Energy and a Shaded Wall. Arab J Sci Eng 39, 9127–9136 (2014). https://doi.org/10.1007/s13369-014-1462-3
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DOI: https://doi.org/10.1007/s13369-014-1462-3