Drizzle, fountains, fans – everything hasn’t been tried to keep public spaces in Austria’s cities relatively cool in the increasingly hot summers. At the technical University of Graz A research team is currently working on a solution that will literally outshine other options. We’re talking about water-filled ceramic cubes that can be assembled into shapes of any size and placed in urban hotspots. What’s special: In contrast to fountains and the like, which require pumps – and therefore electricity – to circulate water, these modules operate without or at least very little energy.
The reason for this is the sophisticated internal structure of the cubes. “The geometry is based on the principle of Triple Periodic Minimal Surfaces,” explains project manager Milena Stavric from the Institute for Architecture and Media. “This means that with a small volume – our cubes have sides of around 40 centimeters – there is a lot of surface area over which the water can evaporate and cool the environment.” The cubes are made of clay that is fired at a comparatively low temperature. This creates a highly porous structure in which a capillary effect works: If you put water in the cube, it is absorbed like a sponge and passed along the fine cavities before it evaporates on the surfaces.
In the future, wood chips and fungal cultures will be added to the clay. The cavities created during the firing process as well as the threads of the growing fungus, the mycelia, could contribute to the formation of an additional fine network of micropores in the structure and thus further improve the cooling performance.
Stavric tested whether the system can actually achieve what the research team is hoping for in the attic of a TU building: where the temperatures are almost sauna-like in summer, the researchers sweated less after setting up a cube: the temperature fell by almost seven degrees. “Experiments under controlled conditions demonstrate effective air-water interactions, which lead to a noticeable reduction in air temperature and increased humidity,” explains Kristijan Ristoski, who describes and documents the development of the system in detail in his master’s thesis.
employees of the TU Graz have already expressed interest in clay cubes for their offices. And in the next few days, a two-by-two-meter wall consisting of several modules will be built on the TU grounds between the institute buildings in order to make the cooling effect noticeable in public spaces.
“The individual phenomena that interact here are already known,” says Stavric. “Our research achievements consist of developing a concrete possible application and developing a special 3D printing process for the raw material.” The question of the specific water requirements for a larger system remains to be clarified. In any case, it doesn’t make the researchers sweat.
