The main purpose of this study was to determine physical parameters of textiles used in harvesting water from fog and dew. Therefore, several kinds of materials in the forms of yarn and fabric were investigated. These materials were a collection of fibers with high, medium and low moisture absorption properties. Porosity and weave structure of yarns and fabrics were diverse. A metallic monofilament made of aluminum with low specific heat capacity was compared with the materials of fibrous structures. . The average of the results was considered as the final outcome in data analysis. Thus, it was found that water-collection efficiency was affected by the physical and structural properties of the samples. In this respect, hygroscopicity, specific heat capacity of material, type of yarn, fineness of fibres/yarns, capillary shape and the cross angle of fibres, ? ( ) were found to be effective parameters. These parameters were analyzed with a mathematical model and statistical methods. The site existence parameter was rated and the correlation between effective parameters and the water collection efficiency was studied using the competitive matrix method. Results showed that when the surface of a material has the potentiality to be cool enough, more water can be collected from air moisture. So, parameters like water absorption, specific heat capacity of material, and the existence of sites for holding moisture on the surface of materials can be considered as effective parameters. Water absorption and existence of sites cause evaporating and cooling the surface of material that leading to increase in condensation of water vapour (air moisture). Specific heat capacity provides conditions for samples to have a cool surface. In addition, existence of sites can be explained by type of yarn, weave construction, fineness of fibres/yarns, the cross angle of fibres and other geometric properties of fibres and yarns.
