A team of scientists at the Advanced Architecture Group in the Institute of Advanced Architecture of Catalonia, Spain is creating passive cooling bricks that could replace or augment air conditioning in residential and commercial spaces. Though they are described as bricks, the more formal description is hydro-ceramics, a ‘sandwich’ created by a layer of hydro-gel spheres with a fabric layer between two outside ceramic layers. The system is based on the perspiration mechanism of human bodies. When temperature in our body rises, our cells release humidity to balance our body temperature. That is why we sweat and this is how the system of these composites performs.

The hydro-gel could be roughly compared to the crystals in a baby’s diaper that absorb moisture and swell up. However, in this case the water then starts to evaporate, causing a thermodynamic action that creates a cooling effect. The cooling effect on building interiors from hydro-ceramics can reduce the indoor temperature by up to 60C because the hydro-gel absorbs up to 500 times its weight in water. The water wicks-in through the fabric and evaporates the same way, creating the cooling effect. But are these bricks part of the envelope or structural?

It was initially developed as an envelope technology, with an initial design including a perforated inner layer to allow air to circulate and activate the evaporation for creating an interior microclimate. However, since it is a material system of a new composite, it is possible to customize and create ceramic bricks that can be structural. There is still a lot of work to be done, such as mass production of affordable bricks. Currently, scientists are looking at 3D-printing the ceramic part, which opens up possibilities for creating mass-customized pieces of different forms and sizes.