We all know that if a teapot of boiling water is placed on the kitchen table, it will gradually cool down. However, its temperature will not fall below that of the table. This is just an everyday real life experience that supports one of the fundamental laws of physics “the second law of thermodynamics” which states that the entropy of a closed natural system must increase over time. That is to say: Heat can only flow only from a warmer to a colder object by itself, and not vice versa.
Interestingly, a device that’s seems to or appears to contradict this fundamental law of physics have been developed by physicists at the University of Zurich. This amazing simple device allows heats to temporarily flow from a cold object to a warm object without an external power supply, thereby appearing to be in contradiction with the law of physics
In order to achieve this, the researchers used a Peltier component, a component commonly used, for example, to cool minibars in hotel rooms. These elements has the ability to transform electric currents into temperature differences. These elements have been used by the researchers in their previous experiments, in connection with an electric inductor, to create an oscillating heat current in which the flow of heat between two bodies perpetually changed direction. But in In this case, heat also flows temporarily from a colder to a warmer object so that the colder object is cooled down further. This kind of “thermal oscillating circuit” in effect contains a “thermal inductor”. It functions in the same way as an electrical oscillating circuit, in which the voltage oscillates with a constantly changing sign.
Before now, the researchers had only operated these thermal oscillating circuits using an energy source. The researching team have now demonstrated for the first time that this kind of thermal oscillating circuit can also be operated with no external power supply.