TU Graz 3D-Printed Ceramic Wall Cools Cities Without Electricity

How the ceramic cooling wall works

The system is straightforward. Water seeps into highly porous ceramic cubes by capillary action. As it evaporates from the enormous internal surface area, it pulls heat from the surrounding air. The result is passive cooling with no electricity, no compressor, and no refrigerant.

The cubes measure about 23 centimeters on each side. They are 3D printed from a ceramic clay mixture using a minimal-surface geometry called a triply periodic minimal surface, or TPMS. That shape uses the least material possible while exposing the maximum surface area for evaporation. The cubes are then fired at low temperatures to lock in the porous structure.

Why 3D printing matters here

Traditional cooling walls are built from standard blocks or panels. Their surface geometry is limited by molding or machining. 3D printing lets the TU Graz team vary the pore structure and channel water distribution through the form itself. The result is a wall that cools more efficiently per kilogram of material.

The team is also experimenting with bio-inspired additives. Sawdust, fungal cultures, and sediment from Lake Neusiedl are being tested as partial replacements for clay. The goal is to lower the embodied energy of the cubes further and use locally available materials.

What it means for cities

Urban heat islands are a growing problem. Trees help, but dense city centers often lack the space or soil depth for adequate canopy cover. Air conditioning shifts the heat outdoors and spikes grid demand. The TU Graz wall offers a third path: passive evaporative cooling at the building or street level.

A two by two meter prototype is already installed at Stremayrgasse on the TU Graz campus. If the scaled-up versions perform as promised, the technology could appear in public plazas, bus stops, and building facades within a few years. The team is now looking for industry partners to move from prototype to production.