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The Eco-Friendly Air Conditioner that Does Not Use Refrigerant Gases: Incoming Revolution?

A German team has developed a device that acts as an air conditioner and heat pump, thanks to a metal alloy "equipped with memory".

A group of German researchers has developed a heating and cooling system that has twice the efficiency of a heat pump and three times as much as an air conditioner. The prototype uses a particular property of some metal alloys to lower or raise the temperature of the air, without the need to use refrigerant gases, which allows the environment to be air-conditioned in an ecological way.


The device is based on the ability of some alloys to "remember" their original form. These are superelastic materials, which can be deformed at will, but then regain the standard configuration depending on the temperature. In technical words, they are called shape memory alloys.


The alloy used by scientists from the University of Saarland is Nitinol, a mix of nickel and titanium that for the occasion served to shape many metal wires, organized in a sort of "muscle bundle". Thanks to their shape memory properties, the cables accumulate large amounts of heat when they are bent, while they release it when they return to their original appearance. The difference between the two conformations is up to 20 degrees.


In summary, the invention consists of a rotating cylinder covered with Nitinol wires. On one side the beam is mechanically deformed and absorbs the heat; on the opposite side the rotation extends the cables, allowing heat to be released. The result is a flow of hot air that comes out on one side and a fresh breeze blowing on the other.


The researchers point out that the heating or cooling power of the system is thirty times greater than the mechanical power required to load and unload the fibers of the metal alloy. Furthermore, according to a note, the new technology "is also environmentally friendly and does not damage the climate, since the heat transfer mechanism does not use liquids or vapors". The team is now working to perfect the device, with a view to future commercial applications.

The Eco-Friendly Air Conditioner that Does Not Use Refrigerant Gases: Incoming Revolution?

Author, Riccardo Tigani  Linkedin Page
General Manager at Linea3C Srl

18th March 2019

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