A study on the thermal performance of Pleurotus Ostreatus/Straw mycelium composites and its application in building envelopes

Abstract

Most conventional construction materials are non-degradable, putting huge burden on our environment at disposal. Mycelium-based composites are formed by aggregating some forestry and agricultural residues with networks of filamentous hyphae, and they are degradable and environmentally friendly. The paper examines the thermal property of Pleurotus Ostreatus/Straw (PO/S) mycelium composites and explores the possibility of using it for building insulation application. Samples of PO/S mycelium composites of different composition and density were prepared. The thermal conductivity was measured by a steady-state thermal measurement approach. It was found that incubation time, preparation method, and composition are important factors for the thermal performance of the material. The lowest thermal conductivity was 0.12 W/m‧K, with the sample (FMC 04) consisting of 75 % Pleurotus Ostreatus primary spawn and 25 % straw substrate and prepared without pressure. With this composition, a series of mycelium-based façade and roof sandwich insulation panels were designed in details. The U-values of the panels were calculated using THERM software, and required panel thickness was investigated. It was found that when the panel thickness reaches 240 mm, two types of wall panels (W1 and W2) and two types of roof panels (R1 and R2) satisfy the energy efficiency requirements of Class A public building in the “hot summer and cold winter” climate zone in China. A cost-benefit analysis shows that implementation of this novel insulation panel is financially sustainable for at least 10 years from now on, if it is sold at a price 5 % more than normal panels.