SEDL / STP / STP1107-EB / STP17697S

Heat and Moisture Transport Through a Glass-Fiber Slab with One Side Subject to a Freezing Temperature

Tao, Y-X
Post Doctoral FellowHead of the Dept.Associate Professor, University of Saskatchewan, Saskatoon, Sask

Besant, RW
Post Doctoral FellowHead of the Dept.Associate Professor, University of Saskatchewan, Saskatoon, Sask

Rezkallah, KS
Post Doctoral FellowHead of the Dept.Associate Professor, University of Saskatchewan, Saskatoon, Sask

Pages: 13    Published: Jan 1991

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Abstract

Experiments were performed of heat and moisture transport through a glass-fiber slab to investigate the effect of condensation and frosting on the thermal performance of insulation. The slab has one side impermeable and subject to a cold temperature (below the triple point of water) and the other side open to a moist air at a room temperature and for various humidity levels. The accumulation of moisture and frost results in an increase in heat loss up to a maximum of twice as much as that for a dry insulation. A comparison between a one-dimensional, numerical model based on a formulation of vapor diffusion in porous media and the experimental results, reveals that significant hygroscopic effects occur in the experiment for initially oven-dried specimens, and contribute to the discrepancy between the transient results of the prediction and of the experiments. For the transient processes, the differences in predictions, excluding the adsorption phenomenon, and the experimental data can lead to a maximum discrepancy of 26% in temperature and of 35% in heat flux.