The Nano-Fridge
Two theoretical physicists, Chris Van den Broeck of Hasselt University in Belgium and Ryoichi Kawai from the University of Alabama, have invented the world’s smallest fridge – well theoretically anyway!
The two scientists claim it would be possible to construct a minuscule fridge powered by the principle of Brownian motion. This motion is the random movement of tiny particles, caused by bumping into surrounding molecules, and is a proven phenomenon in physics. These fluctuations usually hinder cooling, but Van den Broeck and Kawai claim to have found a way round this. (For a more detailed explanation of Brownian motion, see Encyclopaedia Britannica at .
How does it work
They have created a microscopic motor, made out of a single asymmetrical molecule, which transfers heat from a high temperature area to a low temperature area if it is placed between the two. But if the motor is powered in such a way that it rotates in the opposite direction, it means that heat will then flow from the colder area to the warmer one – effectively causing a refrigerating effect, in much the same way as a household heat pump.
But how can such a motor be powered, on a molecular scale? Well in the theoretical model they have developed, Van den Broeck and Kawai use a chiral rod, with paddles at both ends, piercing an insulating membrane. If the molecules around the paddles at one end have more kinetic energy than those around the paddles at the other end, it causes the rod to spin. Force then needs to be applied to make the motor run in the opposite direction, to create a cooling effect.
Technically this would then be an incredibly small refrigerator – although it would have no mechanical parts in the conventional sense, because it creates a cooling effect it can be classed as a fridge.
What could it do?
So what commercial refrigeration applications could such a device be used for? Well there are plenty of places that a normal refrigerating mechanism cannot be used as it simply would not fit – particularly inside computers. These often rely on air cooling mechanisms which still take up a relatively large amount of space and cannot deliver the precise cooling that this device could achieve. It could cool individual semiconductor chips by transferring energy away from the centre of the chip, towards a cooling port. It could also of course cool down other nano technology such as nanoscale machines, which many scientists believe will become much more widely used in the future, according to .
In the meantime, conventional fridges continue to makes their own advances in quality and technology, you can see some of the most up to date models by checking out commercial refridgeration by .
The scientists themselves are very excited about what they have devised – Kawai has stated that “Our Brownian machine magically exploits the random motion of molecules rather than fighting against it”. It may be more science than magic but you have to agree it’s pretty clever!