In a nutshell: Traditional air conditioners and heat pumps employ refrigerant gas to cool down or heat up homes and buildings, bringing potential harm to the environment. A team of European scientists is trying to solve the issue by using new, experimental materials made out of ceramic.

A study recently published in Science describes a new "electrocaloric" material, an air conditioning technology designed to perform its cooling (or warming) duties without using dangerous or potentially polluting gases. By combining a number of existing techniques, scientists from the Luxembourg Institute of Science and Technology in Belvaux have developed a new prototype based on ceramic with a strong electrocaloric effect.

An electrocaloric system heats up when exposed to electric fields, as electrically imbalanced atoms in the material are forced to align in a single direction like in a hair comb. Entropy levels are reduced, and the aligned atoms start vibrating faster, making the temperature rise.

The new prototype uses a fluid flowing between slabs of the ceramic-like material to remove the extra heat. If the electric field is switched off, the effect is reversed with the material becoming colder than ambient temperature and removing heat from the fluid. And then the cycle can start again.

The electrocaloric prototype has shown "superlative performance," materials scientist Neil Mathur at the University of Cambridge remarks. When employed in a refrigerator or an air conditioner, the new material would be used to disperse heat outside a building while keeping the interior environment cold. Conversely, a heat pump would cool down the external environment by extracting heat from it and bringing it inside.

Existing conditioning systems are very efficient, but they need refrigerants such as hydrofluorocarbons or ammonia, which can have direct and indirect greenhouse effects. The electrocaloric prototype has no need for dangerous gases, and it could also be manufactured in smaller, simpler form factors as it removes the need for a compressor.

Despite showing some remarkable capabilities, the prototype technology is not yet ready for commercialization. The Luxembourg scientists need to further refine the tech, increasing the efficiency of the new material. Making the electrocaloric heat pump competitive with the one employed in existing air conditioning systems is their number one priority right now.