3D-printed ceramic walls for passive urban cooling

Researchers at Graz University of Technology developed 3D-printed, highly porous ceramic cubes that use passive evaporative cooling to lower ambient temperatures by nearly 7°C. The innovation offers an energy-efficient alternative to conventional air conditioning and urban cooling

By combining 3D-printing technology with traditional evaporative cooling principles, the team produced porous ceramic cubes capable of significantly lowering surrounding air temperatures without relying on energy-intensive air conditioning.

Led by Milena Stavric, the project leverages triply periodic minimal surface (TPMS) geometries to maximise surface area while minimising material use.

How do the evaporative ceramic cubes work?

The system modernises ancient passive cooling methods, such as clay jugs and traditional wind towers, using digital design and low-temperature ceramic firing:

• Massive surface area:

  • Digitally designed 23-centimetre ceramic cubes feature internal geometries engineered for maximum surface area. Water introduced to the structure spreads rapidly via capillary forces across the porous clay.

• Heat absorption:

  • As water continuously evaporates from the expansive internal surface, it draws thermal energy from the immediate environment, cooling the surrounding air.

• Significant cooling performance:

  • During attic field tests at TU Graz, a single water-filled cube produced a temperature drop of nearly 7°C (12.6°F) in its immediate vicinity, with noticeable cooling spread across the entire room.

Bio-inspired materials and recycled sediments

To further enhance water distribution and overall efficiency, the team explored bio-inspired material blends in their Shape Lab:

• Fungal mycelium integration:

  • Researchers mixed sawdust and fungal cultures into the clay before 3D printing. When fired, the organic fungal network burns away, leaving behind an intricate web of micro- and macro-pores that improves water transport through the cube.

• Sustainable silt reuse:

  • The project is also testing local sediment dredged from Lake Neusiedl as a raw clay input, turning waste material into a functional, sustainable construction resource.

Practical applications and public demonstrations

Designed for indoor spaces (offices, schools, residences) as well as outdoor public areas where shade trees cannot grow, the cooling system is already undergoing real-world testing. A free-standing 2×2 meter clay demonstration wall has been installed at TU Graz’s Campus Neue Technik to showcase the technology’s passive cooling capabilities.