Abstract
In the first part of this study, published in the April 1985 issue of the Journal of Thermal Insulation, the moisture gain of spray-applied fiberglass and cellulose insula tions were experimentally determined for exposure conditions of 10%, 30%, 50%, and 70% relative humidity and 20 and 27 C° temperature difference. In addition, the effect of the moisture gain on the effective thermal conductivity was measured using heat flow sensors and thermocouples. In the second part of this study, a computer model was developed to simulate the moisture gain and its effect on the heat transfer. Vapor and liquid transfer were incorporated by the use of diffusional equations, and condensation/evaporation was estimated by vapor pressure-temperature relation ships. A magnitude and parameter study found that the main transport parameters were the vapor diffusivity and the evaporation coefficient. By varying these parameters within acceptable limits, the moisture gain and effective thermal conduc tivity of the fiberglass were reproduced by the program.
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