Sawdust based core material for eco-friendly Vacuum Insulation Panels (VIPs)

This study presents an alternative core material developed by using waste sawdust powder for eco-friendly Vacuum Insulation Panels (VIPs). This alternative VIP core material was prepared by using locally sourced waste sawdust powder from woodwork industry. Three samples containing varying mass ratios of sawdust and fumed silica were characterized in terms porosity, pore size, density and thermal conductivity. VIP samples of size 150 × 150 mm were prepared using new alternative core material at a pressure of 0.5 mbar. Center of panel thermal conductivity values of VIP samples were measured just after manufacturing and after storing seven days at room temperature. Test results showed that thermal conductivity (center of panel) values increased with higher contents of sawdust in the VIP core. Reducing sawdust mass% in the VIP core sample from 85% to 30% led to approximately 73% decrease in VIP center of panel thermal conductivity from 21.12 mW/mK to 5.52 mW/mK. Thermal conductivity (center of panel) of VIPs containing 30% sawdust, 55% fumed silica and 15% SiC was measured to be 5.52 mW/mK, which is comparable to commercially available fume silica VIPs. Thermal conductivity results show that sawdust powder in VIP core offers a potentially low cost eco-friendly alternative core material by partially replacing fumed silica, the dominant contributor to the VIP environmental impact.