Convection suppression in an attic shaped enclosure

Anderson, Timothy, Duke, Mike and Carson, James 2008, Convection suppression in an attic shaped enclosure, in CHT-08 : Proceedings of the 4th Advances in Computational Heat Transfer International Symposium 2008, CHT, [Marrakech, Morocco].


Title Convection suppression in an attic shaped enclosure
Author(s) Anderson, Timothy
Duke, Mike
Carson, James
Conference name International Symposium on Advances in Computational Heat Transfer (4th : 2008 : Marrakech, Morocco)
Conference location Marrakech, Morocco
Conference dates 11-16 May 2008
Title of proceedings CHT-08 : Proceedings of the 4th Advances in Computational Heat Transfer International Symposium 2008
Editor(s) [Unknown]
Publication date 2008
Conference series Advances in Computational Heat Transfer Symposium
Publisher CHT
Place of publication [Marrakech, Morocco]
Summary In recent times there has been growing interest in the integration of solar collectors, for water heating, into the façade of buildings. However, the design methodology of these devices remains largely the same as typical “stand-alone” collectors. As such it is still common for materials with a high thermal resistance to be used for insulating the rear surface of these collectors.

Unlike a “stand-alone” solar collector that is exposed to the atmosphere at all faces; a building integrated system allows the opportunity for air to act as an insulator at the rear surface of the solar collector. The use of convection suppression devices has been widely discussed in the literature as a means of reducing natural convection heat loss from the front surface of glazed solar collectors. However in this study the use of baffles in an attic was examined as a means of suppressing heat loss by natural convection from the rear surface of a roof-integrated solar collector. The aim of the study was to examine whether the use of baffles would allow the cost of building integrated collectors to be reduced by removing the cost of insulating material.

To determine the effect of baffles in the attic space at the rear surface of the collector, a 3-dimensional triangular cross sectioned enclosure with a vertical aspect ratio of 0.5 and a horizontal aspect ratio of 3.3 was modelled. The flow patterns and heat transfer in the enclosure were determined for Grashof Numbers in the range of 106 to 107 using a commercially available finite volume CFD solver.
It was found that the use of a single adiabatic baffle mounted vertically downwards from the apex, and extending the length of the enclosure, would alter the flow such that the heat transfer due to natural convection was reduced with respect to the length of the baffle.

Furthermore, it was observed that a series of convection cells, not previously reported in the literature, appeared to exist along the length of the enclosure. As such, it may be possible to derive additional benefit in reducing the heat transfer by adding lateral baffles in addition to the single longitudinal baffle modelled in this study.
Language eng
Field of Research 090702 Environmental Engineering Modelling
Socio Economic Objective 970109
HERDC Research category E1.1 Full written paper - refereed
Copyright notice ©2008, CHT
Persistent URL http://hdl.handle.net/10536/DRO/DU:30023088

Document type: Conference Paper
Collection: School of Engineering
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