Peltier minimum temparature to work

  • #1

Main Question or Discussion Point

Dear Experts,

I like to check with you, is there a minimum temperature for a peltier thermal couple to start generating electricity?

I tried putting a peltier on a stove which i was using to cook some food. There is no fire on the stove but its very hot.

I place the hot side of the couple on top of the stove heating element. the other side facing up has nothing on it.

I measured the current and there is none and the cold side of the couple also began to become very hot.

So, even though the hot side is hot, the cold side also becomes as hot.

So, there is no electricity flow.

But i see on the net some videos where bunsen flame is targeted on the hot side and the cold side is left alone and there is electricity flow.

So, i just like to check if the cold side is at room temperature, and the hot side is heated to several hundred degrees, will electricity flow?

Thank you for reading.

regards
Ramone
 

Answers and Replies

  • #2
vk6kro
Science Advisor
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I connected a Peltier device to a multimeter on the 200 μA range.

When I placed my hand on one side of it, I got a reading of about 120 μA.

On the 2 volt voltage range, I got a reading of 80 mV.

So, for a rise in temperature of less than 10°C, I got useful output.


I don't think I would try applying a bunsen burner to the Peltier, though. This would possibly unsolder any soldered connections inside it.
 
  • #3
russ_watters
Mentor
19,408
5,551
You'll want to have a heat sink on the cold side to keep it cooler. A peltier doesn't generate energy if it is hot, it generates energy if one side is made hot and the other side is kept cool.
 
Last edited:
  • #4
Dear Vk6kro and Russ,

Thanks for enlightening.

So am i right to say that while TEG depends on temperature difference, the cold side has to remove the heat fast enough to keep it cool vis-a-vis the hot side.

Is this why TEG cannot be used in car exhaust systems since the hot side would have melted the soldering of the 2 sides of a TEG?

What if aircon air is blow across the cold plate of the TEG?

Has there been such experiments done before?

Thanks again!

regards
Ramone
 
  • #5
vk6kro
Science Advisor
4,081
40
The easiest way to use these is to have one side at ambient temperature, if this is possible.

That is what a heatsink does. If heat reaches the heatsink side of the Peltier device, it is conducted to the fins of the heatsink and quickly dissipated to the environment.

Meanwhile, the other side can get hot or cold relative to the ambient side and this will produce electricity from the leads.

I have a heatsink from a Pentium 4 computer and this looks ideal for such experiments. It has a fan on it which would probably use more energy than the Peltier could generate, though.
 

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