Please use this identifier to cite or link to this item: http://hdl.handle.net/10125/45812

Can Roofs Breathe?

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Title: Can Roofs Breathe?
Authors: Herbert, Douglas
Advisor: Anderson, Amy
Issue Date: May 2008
Abstract: This research investigates using the principles of cross ventilation, stack effect, solar roof, and solar chimney techniques into a single roof design to possibly increase the internal air velocity and lower the internal temperatures for residential structures located in hot-humid climates. The environmental conditions common in hot-humid climates include low wind velocity, increased humidity levels and high ambient temperatures. The most benefi cial way to provide thermal comfort for the occupants living in these climates is to increase air velocity across the body, to lower humidity levels, and to lower internal temperatures. The goal is to design a roof system incorporating passive cooling and solar-induced cooling principles which will potentially increase the potential thermal comfort while outperforming conventional residential roof systems without using mechanical systems. The design in this research was tested using physical modeling with data collection and computational simulation using CosmosFlo Computational Fluid Dynamics (CFD) software. The software was used for the computational analysis used to estimate air velocity within the roof testing modules. The preliminary testing results demonstrate a decreased internal temperature using the proposed design over those internal temperatures using typical roofi ng methods. The air velocity test data from the physical models has proved unreliable due to location of the physical testing modules which were infl uenced by higher wind speeds associated with the trade wind fl ow inherent in Hawai‘i. The temperature differences proved large enough between the air inlet vents, interior space, and air cavity to provide increased air movement in the interior of the test v modules. The outcome of this research is encouraging and shows promise that the proposed design could possibly be benefi cial to increase the thermal comfort levels for residential structures in the hot-humid climates. Further exploration and a large amount of research and development are still needed to make this design more effi cient and cost effective for possible wide spread use.
Pages/Duration: 123 pages
URI/DOI: http://hdl.handle.net/10125/45812
Appears in Collections:2008



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