TU Graz Cools Rooms by 7 Degrees With 3D Printed Ceramic Cubes and No Electricity

How the cooling works

The system relies on evaporative cooling, a principle as old as clay water jugs. Water evaporating from a surface draws heat from the surrounding air. TU Graz's version of this idea uses 3D-printed ceramic cubes roughly 23 centimeters across. The cubes are printed from a ceramic clay mixture and fired at low temperature to produce a highly porous structure. Water enters the pores by capillary action and spreads across an enormous internal surface area. As it evaporates, it pulls heat from the room.

A test in a hot attic at TU Graz's campus measured a temperature drop of almost seven degrees Celsius in the immediate vicinity of a single water-filled cube. The team reports the cooling effect was clearly noticeable across the entire room.

3D printing makes the geometry possible

Milena Stavric from the Institute of Architecture and Media at TU Graz explains the advantage of using additive manufacturing for this application. Traditional manufacturing methods cannot produce the complex, highly porous geometries the team needed. 3D printing lets them vary the internal structure precisely, maximizing the water storage and evaporation surface within a compact volume.

The cubes also come in a bio-inspired variant. Fungal cultures and sawdust are mixed into the clay before printing. Mycelium, the thread-like fungal network, grows through the material before firing. The organic matter burns away in the kiln, leaving a network of micro- and macro-pores that distributes water even more efficiently through the cube.

Sustainable building material angle

The research team is also testing dredged sediment from Lake Neusiedl, a shallow lake near Graz that requires regular dredging to manage silting. That sediment normally has no commercial reuse. Processing it as a 3D-printable building material could give waste a second life while producing functional cooling components.

Real-world installation

A free-standing two-by-two-metre demonstration wall built from these cubes is now installed at TU Graz's Campus Neue Technik in Graz, Austria. A display about the project is also running at the city's Museum of Perception. The team is open to inquiries from planners and construction companies evaluating the technology for commercial use.

The researchers position the cubes as a direct alternative to energy-intensive air conditioning in homes, offices, schools, and public spaces, especially in urban areas where tree canopy cover cannot keep up with rising temperatures. The only operating cost is the water.