An experimental investigation of moisture absorption and condensation in fibrous insulations under low temperature

This paper reports on an experimental investigation on the temperature and water content distribution within the porous fibrous battings sandwiched by an inner and outer layer of thin covering fabrics using a novel sweating, guarded hot plate. Experimental results for four combinations out of two types fibrous battings (one hydrophobic and non-hygroscopic polyester and the other hydrophilic and hygroscopic viscose) and two types of covering fabrics (one highly permeable nylon fabric and the other less permeable laminated fabric) have been obtained. It was found that most of the changes in temperature distribution took place within 1/2 h of the tests and moisture absorption by the hygroscopic fibers affects the temperature distribution. The water content accumulates with time and higher water content was found at the outer regions than that at the inner regions of the battings. The accumulation and distribution of water content is a combined result of moisture absorption, condensation and liquid water movement. Further theoretical modeling based on the reported experimental results is needed in order to better understand the mechanism. (C) 2003 Elsevier Science Inc. All rights reserved.