Evaluating the thermal insulation performance of composite panels made of natural Luffa fibres and urea-formaldehyde resin for buildings in the hot arid region

ABSTRACT This study investigates the performance of thermal insulation panels composed of the natural Luffa fibres with urea-formaldehyde resin for buildings in the hot arid region. The study has been done experimentally. The work has included the collecting of Luffa fibres from local gardens in Iraq, manufacturing the specimens and measuring the thermal conductivity for different thicknesses, densities and temperatures. The results show that the thermal conductivity of Luffa/urea-formaldehyde composite ranges between 0.22 and 0.25 W/m K. Furthermore, the k-value of the panel may differ by 5–15% depending on the thickness under testing, and by 10–20% depending on the density. However, the main advantage of Luffa composites is that the k-value of the panel is not affected too much at high temperatures, where it has been increased up to 0.26 W/m K (or by 15%) as maximum by the increase of source temperature up to 80°C. This feature has encouraged the use of these panels as external insulation layers in the hot climate region. The results taken from a simulation programme have revealed that the energy saving in the cooling load due to the use of 30-mm insulated panels made of these composites and covered by reflective foils can reach up to 30%.