The influence of convection on the thermal performance of loose-fill attic insulation has been investigated using measurements and simulations. Thermal resistance measurements have been performed in a large-scale attic test model, with and without attic ventilation, and on loose-fill rock wool and fiberglass insulation. Measurements of natural convection have shown that the critical modified Rayleigh number for attic insulation in a conventional attic floor is approximately 22. The maximum decrease in measured thermal resistance due to natural convection was 25% compared to that obtained at the onset of convection. There was no indication of a decrease in the total thermal resistance of the attic floor due to attic ventilation.
Wilkes, K.E.
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2.
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and Mc Caa, D.J. (1991). The Effect of Natural Convective Air Flows in Residential Attics on Ceiling Insulation Materials, Insulation Materials: Testing and Applications, Vol. 2, ASTM STP 1116, pp. 263–291, Philadelphia.
3.
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and Miller, E. (1983). Thermal Resistance of Loose-Fill Fiberglass Insulation in Spaces Heated from Below. In: ASHRAE/DOE Proceedings. Conference on the Thermal Performance of the Exterior Envelopes of Buildings II. ASHRAE SP 38. pp. 720–733.
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5.
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7.
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8.
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9.
Wahlgren, P.
(2001). Convection in Loose-Fill Attic Insulation – Simulations and Large-Scale Measurements. In: Proceedings of the 8th Conference on the Performance of the Exterior Envelopes of Whole Buildings, Clearwater Beach, Florida.
10.
Wahlgren, P.
(2002). Measurements and Simulations of Convective Heat Transfer in Loosefill Attic Insulation. To be published in the Proceedings of the 6th Symposium on Building Physics in the Nordic Countries, Trondheim, Norway.
11.
Wahlgren, P.
(1998). Convective Processes in Loose-Fill Attic Insulation–Metering Equipment. In: Proceedings of the 7th Conference on the Thermal Performance of the Exterior Envelopes of Buildings, Clearwater Beach, Florida. ISBN 1-883413-70-2.
12.
Serkitjis, M.
and Hagentoft, C.-E. (1998). The Influence of Natural Convection on the Heat Transfer in an Air Filled Porous Medium Bounded by an Air Layer. Nordic Journal of Building Physics, 1: ISSN 1402-5728.
13.
Serkitjis, M. (1995). Natural Convection Heat Transfer in a Horizontal Thermal Insulation Layer Underlying an Air Layer, Thesis, Department of Building Physics, Chalmers University of Technology, Sweden. ISBN 91–7197-195-5. ISSN 0346-718X.
14.
Langlais, C.
, Arquis, E. and Mc Caa, D.J. (1990). A Theoretical and Experimental Study of Convective Effects in Loose-Fill Thermal Insulation, Insulation Materials: Testing and Applications. ASTM STP 1030, pp. 290–318, Philadelphia.
15.
Silberstein, A.
, Arquis, E. and Mc Caa, D.J. (1991). Forced Convection Effects in Fibrous Thermal Insulation, Insulation Materials: Testing and Applications, Vol. 2. ASTM STP 1116, pp. 292–309, Philadelphia.
