Particle Sizes and Thermal Insulation Properties of Some Selected Wood Materials for Solar Device Applications

Abstract

This study investigates the thermal properties of some selected wood materials found in the rain forest of South Western Nigeria. These wood species are Alstonia boonei (Ahun), Pterygota macrocarpa (Oporoporo), Milicia excels (Iroko), Pterocarpus (Osun), Celtics zenkeri (Ita) and Pterocarpus mildraedii (Ure). Particle sizes of 300 µm, 600 µm and 850 µm were sieved out from each of the different wood materials of the six varieties of wood species. The samples were machined to appropriate disc shape using fabricated hydraulic-press mould. The modified Lee's disc apparatus was used to determine the thermal conductivities of the samples. The result shows that thermal conductivity of the selected wood shavings change with particle sizes. Except for the Pterygota marcrocarpa, other samples had least thermal conductivity values at 600 µm particle size ranging from 0.045-0.067 Wm -1 K -1 . This range fall within the thermal conductivity values of commonly used solar flat plate collectors. In addition, 600 µm pose the best insulation among the particle sizes considered. Hence, the selected wood materials could be used as industrial insulators as their thermal conductivity values fall within the range of existing industrial thermal insulators. The materials could also serve as good potential devices as heat resistant. Keyword: Thermal conductivity, Particle size, Lee's disc, Industrial insulator