Towards building homeostasis through a low-cost biomimetic synthetic foam for building surface cooling and energy saving

Evaporative cooling has been demonstrated as one of the most effective means to reduce a building's energy consumption and achieve homeostasis in buildings without intensive energy demands. In this research, a novel biomimetic inorganic synthetic foam material (BMSF) was developed from reclaimed fly ash cenospheres for building surface cooling. The BMSF material is synthesized from an abundant industrial byproduct (i.e., fly ash cenosphere) through a low-cost and high-yield two-step process. X-ray microtopography (XRM) and scanning electron microscopy (SEM) tests revealed that BMSF has a microstructure that resembles that of the keratinous skin of African elephants and certain desert lizards to enable water to be stored and transported effectively through capillary actions. Experiments were carried out to quantify the evaporative behavior and cooling effect of the material and building roofs equipped with the BMSF panels. The experimental results indicate remarkable cooling performance - i.e., BMSF panels with protruded surfaces have higher evaporation rates than that of open water surface and a surface temperature reduction of 15 degrees C-25 degrees C was achieved. Lastly, case studies were carried out on a single-story commercial building in Los Angeles, California, and the results demonstrate that the new evaporative cooling surface material is able to achieve passive cooling for buildings in areas with a mild climate and low relative humidity.