A new form of composite facade material developed by students in Spain is capable of reducing the temperature of building interiors by as much as five degrees Celsius simply by exploiting the cooling properties of the evaporation process.

The Hydroceramic facade consists of a mixture of fabric, clay and hydrogel - a highly absorbent substance which serves as the key to its enhanced cooling ability.

The hydrogel is a type of slow-evaporating solid polymer whose volume can expand by as much as 400 times via the absorption of water.

Image of hydrogel spheres

Hydrogel spheres

Image of hydrogel spheres resting on ceramic layer

Hydrogel spheres resting on ceramic layer

The copious amount of water absorbed by the hydrogel enables it to cool down its immediate surroundings, as this water gradually evaporates away and the polymer is restored to its normal, dehydrated state.

Tiny balls of the polymer are placed in the middle of the facade, sandwiched between the interior and exterior ceramic layers that are moulded to the shape of the hydrogel spheres.

The interior ceramic layer contains semi-spherical depressions that are designed to push the hydrogel outward into circular holes in the external ceramic layer that provide space for the it expansion following the absorption of water.

During inclement weather, the hydrogel absorbs rainwater, which then evaporates in warmer conditions and thus cools the interior of buildings to which the Hydroceramic facade is affixed.

The Hydroceramic was developed by students at Barcelona's Institute for Advanced Architecture of Catalonia (IaaC), who claim that the composite material can achieve indoor temperatures reduction of as much as four to five degrees Celsius.

Given that HVAC systems account for such a significant chunk of electricity consumption, this powerless method of temperature reduction translates into major energy savings.

Structural diagram of the Hydroceramic  Click to enlarge

Structural diagram of the Hydroceramic
Click to enlarge

The IaaC students estimate that the temperature regulation made possible by the facade material results in a 28 per cent reduction the energy consumption of an average medium-sized AC system - equivalent to savings of 80 kilowatt/hours, or 56.6 kilograms in carbon emissions, each month.

In addition to the remarkable efficiency gains made possible by the material, its cost of production is comparatively low given the simplicity of its material composition and structure.

The students recommend the installation of the hydroceramic facade on buildings that already possess efficient natural ventilation systems and are capable of dealing with the increased moisture levels required to make it effective.