Elephant skin-inspired mycelium tiles for thermal regulation of buildings

Of all types of ecosystems, cities are the most polluting and this pollution affects more than 50% of the global population. One main cause for this pollution is related to the energy used to heat or cool down buildings. Currently, only 15% of households in Southeast Asia have an air conditioner, but this number is expected to rise, leading to an increase in demand in energy consumption, electricity and CO2 emissions which could further worsen global pollution and climate change. There is therefore an urgent need to find alternative solutions to cool buildings and regulate their temperatures. In this paper, inspiration is taken from elephants who live in very hot climates. Elephants can cool themselves thanks to the wrinkles on their skin that can limit heat gain, dissipate energy by evaporative cooling and store water. To emulate elephants’ cooling, tiles with elephant skin-inspired surface texture are designed. Computational simulations are performed to evaluate the effect of local shading due to the texture. Experimental tiles are produced using a biodegradable and natural material grown by a fungus, Pleurotus Ostreatus. These tiles are mycelium-bound composites (MBCs) where the fungus grew on bamboo microfibers, developing an interconnected web of cells called the mycelium that binds the microfibers together. The thermal properties of the tiles were measured for heating and cooling on the textured and flat side. The results show the tiles have anisotropic properties with a significant improvement by 25% in the cooling of the textured side over the flat side. In simulated rain conditions, the cooling is further improved by 42% as compared to dry conditions. The elephant-mycelium tiles are therefore promising for thermal regulation of building in Southeast Asia environments.