TU Graz 3D Printed Ceramic Cubes Cool Rooms by Nearly 7C

A field test at Graz University of Technology recorded a temperature drop of almost 7 degrees Celsius near a water-filled, 3D printed ceramic cube placed in a hot campus attic. The result validates a design that combines centuries-old evaporative cooling with modern additive manufacturing.

How the geometry does the work

The cubes have sides of roughly 23 centimeters. They are 3D printed from a ceramic clay mixture using a triply periodic minimal surface geometry, then fired at low temperatures to produce a highly porous structure.

Water drawn in by capillary action spreads through the geometry and evaporates across a large surface area, pulling heat from the air the same way clay jugs and wind towers have for centuries.

"This has been working for centuries, both in clay jugs and in traditional wind towers," said Milena Stavric, Associate Professor at TU Graz's Institute of Architecture and Media. "The key technological advance here lies in the use of 3D printing, which enables us to produce highly complex, porous and functionally optimised geometries from clay mixtures. These special structures store water particularly efficiently and, despite their small volume, create an enormous evaporation surface."

Bio-inspired improvements

The team is testing bio-inspired blends in the institute's Shape Lab, adding fungal cultures and sawdust to the clay as a growth medium. A mycelium network spreads through the mixture before printing and firing; the fungal filaments and sawdust burn away, leaving micro and macro pores that improve how water moves through the cube.

Attic test confirmed the effect

"The cooling effect was clearly noticeable throughout the room," said Kristijan Ristoski, a researcher at TU Graz who wrote his master's thesis on integrating the cubes and their water supply into a cooling wall.

The team is also testing dredged sediment from Lake Neusiedl as a possible cube material. Two demonstration walls are already in place: a two-by-two-meter wall at TU Graz's Campus Neue Technik and another at the Museum of Perception in Graz.

"Our aim is to provide cooling where people suffer particularly from the heat — for example, in cities where trees are sometimes unable to provide sufficient cooling," Stavric said. "To achieve this, we rely on natural cooling principles rather than energy-intensive air-conditioning technology."

The project was developed with TU Graz's Institute of Building Physics, Services and Construction and funded by Austria Wirtschaftsservice GmbH through its proof-of-concept programme.