Can an electric circuit absorb heat?

Question

I don't remember where I saw this, but I believe I read somewhere that if one places two different kinds of conductors next to each other in a circuit, running current in one direction produces heat, while running current in the other direction absorbs it. Did I make this up, or is there something remotely like this?

Aha! I think I found it. Apparently I'm thinking of the Peltier Effect.

http://en.wikipedia.org/wiki/Thermoelectric_cooling

Answer 1

The short answer is no, a circuit cannot absorb heat.

Electrons don't know which way they are flowing in a wire, and there will always be an ohmic loss. One exception is with superconducting materials, in which case electrical current flow does not generate heat, and its flow is essentially lossless.

Having said that, there are devices called thermoelectric coolers that work on the Peltier effect. These devices are constructed with chunks of material assembled between two plates, typically made of ceramic.

The device operates by creating a termperature difference between the two surfaces when you run a DC current through it.

When electrical current is run through the material in one direction, it causes one plate to get cold, and the other to get hot. If you run the current in the other direction, the opposite effect occurs. The hot plate now gets cold, and the cold plate now gets hot.

Usually, current is run in one direction only. The hot surface is attached to a big heatsink to actually prevent it from getting too warm. This causes the cold plate to get even colder. But even with that, the hot side gets hotter than the cold side gets cold. That is, there is a net consumption of electrical power which gets dissipated as heat throughout the overall circuit.

But this is also true of a kitchen refrigerator, which also gets cold when electricity is run through the device. (Don't forget though that the cooling coils on the back of the refrigerator get hot.). A TE cooler is simply a solid state refrigerator.

There are no devices that inherently get colder when electrical current flows through them.

Hope this helps,

-Guru

Answer 2

Your wrong but your right ( in a way ). It's not heat that's transferred,( although created in the process), it's the associated magnetic field, created by the electricity in the first wire, that passes over to the second. That is what, in effect, is "absorbed" and creates an electric current in the second wire. It's known as a Transformer. Go to "transformer" in "How does it work" website, for a description and diagram.

Answer 3

Peltier Effect devices use certain semiconductors like bismuth telluride. The device itself doesn't absorb heat, it just moves it from one side of the device to the other.

Answer 4

heat may just be regulated...
not exactly absorbed...
the big factor is the components that make up the circuit....
components that change resistance as a reaction to heat...
heat is 'absorbed' but there is still heat...
and it is never possible that there is absence of it...

Answer 5

I can't answer you as to whether "you made it up" or not.

I can tell you that one of the laws of thermodynamics is that heat will "move" from the "hotter spot" to the "cooler spot" until both are approx. the same temperature (ie they reach equilibrium). That's simplified but that how it works. It doesn't matter what the material is or whether it's an electrical circuit.

Answer 6

Heat is a form of energy associated with and proportional to molecular motion. It can be transferred from one body to another by radiation, conduction, or convection.

Heat of atomization is the energy required to dissociate one mole of a given substance into atoms.

Heat of combustion is the heat evolved when a definite quantity of a substance is completely oxidized (burned).

Heat of crystallization is the heat evolved or absorbed when one mole of given substance crystallizes from a saturated solution of the same substance.

Heat of formation is the heat evolved or absorbed when one mole of a compound is formed in their standard state from its constituent elements.

Heat of fusion is the heat required to convert a substance from the solid to the liquid state with no temperature change (also called latent heat of fusion or melting).

Heat of hydration is the heat evolved or absorbed when a hydrate of a compound is formed.

Heat of reaction is the heat evolved or absorbed as a result of the complete chemical reaction of molar amounts of the reactants.

Heat of sublimation is the energy required to convert one mole of a substance from the solid to the gas state (sublimation) without the appearance of the liquid state.

Heat of vaporization is the heat required to convert a substance from the liquid to the gaseous state with no temperature change (also called latent heat of vaporization).


heat capacity
Heat capacity is defined in general as dQ/dT, where dQ is the amount of heat that must be added to a system to increase its temperature by a small amount dT. The heat capacity at constant pressure is Cp = (∂H/∂T)p; that at constant volume is CV = (∂E/∂T)V, where H is enthalpy, E is internal energy, p is pressure, V is volume, and T is temperature. An upper case C normally indicates the molar heat capacity, while a lower case c is used for the specific (per unit mass) heat capacity.

Answer 7

I think it is a solid state heat pump.It will not absorb heat but it will transfer heat.

Answer 8

some energy in a circuit is converted to heat energy and is "lost".
i don't think it absorbs heat but rather it releases heat. i think both circuits will emit heat.