Heat flowing from cold to hot without external intervention by using a "thermal inductor"

Area of Science:

• Thermodynamics
• Thermal Engineering
• Electrical Engineering

Background:

• Cooling boiling water to freezing using only ambient temperature is thermodynamically unexpected.
• Conventional heat transfer typically requires an external driving force or energy input to move heat against a temperature gradient.

Purpose of the Study:

• To introduce and demonstrate the concept of a "thermal inductor" analogous to an electrical inductor.
• To enable heat transfer from a colder body to a warmer body without external intervention, challenging conventional thermodynamic expectations.

Main Methods:

• Constructing a thermal inductor using a Peltier element and an electric inductance.
• Imposing inertia on heat flow to drive temperature differences.
• Conducting experiments to demonstrate the device's operation and thermodynamic compliance.

Main Results:

• The thermal inductor successfully drove temperature differences to change sign, enabling heat transfer from a cold to a hot body.
• The process demonstrated quasi-equilibrium states, fully adhering to the second law of thermodynamics.
• The system achieved unexpected cooling, bringing boiling water down to freezing temperatures.

Conclusions:

• The thermal inductor provides a novel extension of the electrical-thermal circuit analogy.
• This technology offers potential for passive cooling of hot materials below ambient temperature.
• Further advancements in thermoelectric materials could enhance the efficiency and applicability of thermal inductors.