Power generation from heat???

[Technoboy]

How about generating power from heat. Is it possible? (i am not talking about generating power by using steam)

It will be a great achievement if we can do that.There will be a lot of advantages.
Just imagine a mobile battery dissipating heat and getting charged from the same heat!

Any idea on this matter?Any researches going on?

 

[ninju]

plenty of methods available. seeback effect is one, where if a junction between two different metals is heated, it results in a potential drop across the junction.

it can be done using a crystal too. There are crystals called pyroelectric crystals. This wikipedia entry seems to be fairly accurate and understandable.

Pyroelectric crystal - Wikipedia, the free encyclopedia

Pyroelectricity - Wikipedia, the free encyclopedia

i don't think you can take energy from a battery and recharge it. It can prolong battery life but it won't be sustainable. you failed to account for a basic thermodynamic quantity called entropy.

 

[Technoboy]

Is these methods implemented in any devices?
It seems the Thermocouple or seeback effect is not much practically possible,but pyroelectric crystals seems interesting.

 

[ninju]

seeback effect is practically used where no other method is possible.

Radioisotope thermoelectric generator - Wikipedia, the free encyclopedia

crystals might lose their crystalline nature due to exposure in this case.

Theoretically, i didn't find anything that might hinder their deployment, but i couldn't find any credible literature suggesting their usage in any existing thing. However, they are used as sensors at present.

 

[thannara123]

i Think the mobile battery heat is not enough because generated voltage due to Seebeck effect is very low

 

[dick_freebird]

I have run Peltier modules in reverse just to see. With a lot
of heat input, you can get them to barely run the cooling fan
they need on the "cold side" (they work on heat flux, temp
difference, not just being hot after all). The devices optimized
for Peltier coefficient are not optimized for Seebeck or for
max temperature range.

Thermopiles have been around a very long time. Deep space
probes with RTGs use a hot core and thermopiles to make the
electrical supply. Inefficient, weak, and about as simple as
can be. Aside from the glowing chunk in the middle.

 

[mtwieg]

Lenear Tech has a few chips and evaluation kits for low power thermal energy harvesting. Look up LTC3108. It's nice for running a small MCU and a wireless transceiver at low duty cycle.

 

[BradtheRad]

The Stirling engine generates power from heat.

Wikipedia:
Stirling engine - Wikipedia, the free encyclopedia

Somewhere on the web I saw a demo model made from materials found around the house. It was powered by a candle.

Youtube has several videos of operating Stirling engines.

 

[andre_luis]

The Entropy principle of thermodinamic, introduces the concept that, despite some dissipated energy can be reintroduced to system, the overal low eficiency of the process don´t allow proccess it continouslly.

+++

 

[tpetar]

Peltier can produce electricity, if one side is heated and other cooled (make temp difference) on wires of peltier will get voltage.

 

[gagangc]

Hi technoboy ,I too had similar doubt

Energy harvesting from pyroelectric materials is done by providing temperature fluctuations and electric field.Frequency of electric field applied has a great effect on amount of energy harvested.But my doubt is,when making a real device to harvest energy from waste heat ,temperature fluctuations can be provided but from where will we get electric fields of required frequency?.