The aim of this research was to investigate the thermal performance of Double skin facades (DSFs) for office buildings in Amman. Special attention was given to the role of cavity-integrated shading slats. The study was conducted through a parametric study concerning configuration and design parameters of both DSF’s cavity and shading slats, in addition to boundary conditions. For the purpose of this study, a CFD-Fluent model was developed and validated. Besides, a new method for more accurate representation of solar radiation (as boundary conditions) was developed. Both RNG k-ε and SST k-ω turbulence models were used. The Discrete ordinates (DO) radiation model with non-gray option was selected for modelling of radiation heat transfer. Simulations confirmed that both the width of the cavity and the size and arrangement of openings would have a significant impact on overall performance of the system. The aspect ratio (H/W) of the cavity would further impact its operation, which could contribute to 77% and 26% increase in ventilation and temperature for inner glass surfaces, respectively, of a simple cavity. In addition, among other design parameters, the size and surface emissivity of integrated slats would have the largest influence on the natural ventilation rate in the cavity. The inner glass surface temperature is mainly influenced by the inclination angle and position of these slats in addition to the internal and external environmental conditions. The influence of these slats is also dependent on the aspect ratio of the cavity. Detailed design of these slats would play a further role, together with the boundary conditions (incidence angle) and other design parameters of the cavity (H/W aspect ratio). In Amman, DSFs were shown to have a good performance during heating seasons, as they would enable indoor thermal comfort and ventilation requirements to be met by passive means. During cooling seasons, DSFs with integrated slats would also be able to reduce total solar heat gains if sufficient ventilation could be provided for its cavity. However, artificial cooling is still required for such a hot climate. Controlling the cavity openings is highly recommended for both scenarios. It is recommended that the cavity width is at least 0.6m, the glass transmittance is about 0.8, the size for integrated slat is 20% of the cavity width, and the optimum surface emissivity of the slats is about 0.2. Slats should preferably be placed at mid of cavity or be adjustably according to the seasonal requirements. Optimum inclination angles for slats were found to be 45° degrees and 30° degrees for summer and winter, respectively. General recommendations and design guidelines were provided.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:719669 |
| Date | January 2017 |
| Creators | Amaireh, Ikrima Abd El-Karim Mohammad |
| Publisher | University of Nottingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://eprints.nottingham.ac.uk/43290/ |
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