Thermal performance and Feasibility Study Using a Straw-Based Thermal Insulation in Geothermal systems

Straw is the part of the stem (or stubble) of certain grasses, known as "straw cereals", and is most often a by-product or waste product of cereal production. In northern Algeria, it is produced in all cereal growing regions. It is generally used for animal feed. In this study, straw waste is used as a bio-material for thermal insulation in bioclimatic constructions and especially in geothermal applications, and the thermal insulation needs in a geothermal system is discussed. Furthermore, thermal performance of wheat straw aggregates bio-based material is tested for several thicknesses until stable results are achieved, using conduction heat transfer tests or heating flat plate. This method is based on the temperature difference measuring across the sample (inlet and outlet) and finally, compared it with other commercial geothermal insulation materials. Obtained results give us an idea of the energy gains to be expected from the bio-based materials manufacture to be used in geothermal systems comparing to conventional materials. It is noted that, the optimum thickness of the insulation material based on straw is 2cm, giving a temperature gradient around 9°C versus 16°C for conventional materials. Straw organic waste material is a promising candidate as an alternative insulating material for low-carbon and green buildings targets. Which are in line with the objectives set by the Algerian government as part of the fight against climate change, in particular the development of renewable energies, the promotion of energy efficiency as well as clean technologies and waste recycling.