Biomimetic envelope: a new strategy for limiting surface overheating in buildings

In recent times, most of the energy consumed globally is attributed to the building sector. In this scenario, it is necessary to intervene at the building level with passive strategies to achieve indoor comfort levels by reducing energy use and getting closer to the idea of a Nearly Zero Energy Building (NZEB). These strategies, when applied at the building level, can reduce the amount of energy used in buildings, as well as the amount of GHG emissions in the atmosphere, consequently decreasing the large-scale phenomenon of Urban Heat Island (UHI). In this context, solutions focusing on the imitation of nature, i.e. biomimetic architecture, have recently gathered large attention among researchers and practitioners worldwide. In line with this, based on research studies showing that black and white stripes of the zebra have a thermoregulatory function in the animal, this study tackles the possible application of zebra-inspired stripes to the external walls of the building envelope. Indeed, due to the different absorption coefficients of the white and black stripes, differential surface overheating could be generated locally. This would lead to the production of small convective motions thanks to the different air densities, as the air near the black stripes would tend to rise while heating and the air near the white stripes would tend to stay at the bottom being cooler. The aim of the present work is to investigate the production of a real cooling effect that can be applied to achieve improved indoor comfort levels.