3D Printed Ceramic Cubes Cool Rooms by 7 Degrees Without Electricity

A team at the Institute of Architecture and Media at Graz University of Technology in Austria has built passive cooling blocks that need nothing but water and air to work. The cubes are 3D printed from a ceramic clay mixture, then fired at low temperature to stay highly porous. When you fill them with water, capillary action draws the liquid through the material and evaporation does the rest.

The gyroid geometry

The key to the design is the internal structure. The team uses a triply periodic minimal surface, specifically a gyroid lattice. That shape has no dead ends or sealed pockets, so it prints without supports and exposes an enormous amount of surface area to the air relative to the volume of material. Water spreads across that surface and evaporates continuously, pulling heat away from the surrounding space.

The cubes measure roughly 23 centimeters on each side. In a test inside a hot attic on the TU Graz campus, researchers measured the air near one water-soaked cube at nearly 7 degrees Celsius cooler than the rest of the room. The effect was noticeable across the entire space, not just in a thin layer next to the block.

Adding biology to the mix

The team went further by adding fungal mycelium and sawdust to the clay mixture before printing. During firing, the organic material burns away and leaves behind a network of fine capillaries and larger voids inside the ceramic. Water moves through those channels more easily than through a uniform clay block, increasing the evaporation rate.

The bio-inspired formulation is not just a lab curiosity. The researchers are experimenting with sediment dredged from nearby Lake Neusiedl as a raw material, giving waste a second life as a building component.

Real-world installations

A two-square-meter cooling wall built from these cubes is already installed at Campus Neue Technik on Stremayrgasse in Graz. Another installation sits at Graz's Museum of Perception. Both demonstrate that the concept scales beyond a single block.

What it cannot do yet

This is not an air conditioning replacement. Performance depends on humidity, airflow, and a steady water supply. Scaling to whole buildings introduces questions about mineral buildup, frost resistance, cleaning schedules, and hygiene. The team is aware of all of these. For now, the cubes are a strong proof of concept for low-energy cooling in spaces where running AC is impractical or too costly.