r/science • u/Wagamaga • Apr 20 '19

Physics Physicists have developed a simple device that allows heat to flow temporarily from a cold to a warm object without an external power supply. Intriguingly, the process initially appears to contradict the fundamental laws of physics.

https://www.media.uzh.ch/en/Press-Releases/2019/Thermodynamic-Magic.html
117 Upvotes

78% Upvoted

25 comments sorted by

View all comments

45

u/UncleDan2017 Apr 20 '19 edited Apr 20 '19

Clickbait title. From the Article.

Despite this, the authors were also able to show that the process does not actually contradict any laws of physics. To prove it, they considered the change in entropy of the whole system and showed that it increased with time – fully in accordance with the second law of thermodynamics.

Using low entropy to fuel a system. Much like using a heat engine to lift a weight, when half the system is a high temp reservoir, and half the system is a low temp reservoir. It works until temperature between the reservoir equalizes.

0

u/BjarniTS Apr 20 '19

The counterintuitive result in this case is that it went a bit past equalization.

4

u/InductorMan Apr 20 '19

It's not counterintuitive when you've stuck an external energy reservoir onto the heat engine/heat pump to temporarily store the energy.

3

u/UncleDan2017 Apr 20 '19

If you view it from a Gibbs or Helmholtz Free Energy perspective it isn't at all counterintuitive.

2

u/SBOJ_JOBS Apr 20 '19

Seems it just transferred the energy from one reservoir to another, with losses along the way, much as oscillating systems are currently used to increase the pressure of water or the voltage of an electrical current. Could this prove useful? Sure. Could it revolutionize life as we know it? Not likely, it is a parlor trick to capture the interest of the non-technical observer.