AIR FILTRATION WITH MOISTURE AND FROSTING PHASE-CHANGES IN FIBERGLASSINSULATION .1. EXPERIMENT

A laboratory apparatus has been constructed to subject fiberglass insu lation to one-dimensional moist airflow and heat transfer with tempera tures from 20 to -20 degrees C. Using this apparatus, the effects of a ir exfiltration and infiltration on the heat and moisture transport ch aracteristics within a medium density fiberglass insulation material a re investigated experimentally for one-dimensional transient condition s. The experimental results, which are typical of cold climate buildin g envelope applications, indicated that the adsorption process had a s ignificant influence on the temperature distribution over much of the warm portion of the slab during air exfiltration shortly after the tes ts began. Furthermore, for all of the air exfiltration tests carried o ut, the majority of the moisture and frost accumulation was within the insulation slab adjacent to the cold surface. For air infiltration, i t was discovered that the drying rate was substantially higher for low er airflow rates.