Peltier didn't generate electricity

Thread Starter

Tom gayle

Joined Sep 20, 2021
84
I try to heat peltier device with 12v 0.18a dc fan.it wouldn't run.why peltier didn't generate electricity.why? please tell...
 

crutschow

Joined Mar 14, 2008
34,818
Do you mean you are trying to run the fan from the Peltier device?
What are the characteristics of the device, and how are you heating it?
 

Ya’akov

Joined Jan 27, 2019
9,264
Peltier devices produce electricity in proportion to the difference between one surface and the other. Even if you cool one side and heat the other you are unlikely to get enough power to run a 12V fan.

I assume you are using a typical 30x30mm cooler. There is little possibility of running anything useful from the power it would produce, and in any case, you will always have to use a great deal more energy to produce that little bit.
 

Thread Starter

Tom gayle

Joined Sep 20, 2021
84
Do you mean you are trying to run the fan from the Peltier device?
What are the characteristics of the device, and how are you heating it?
Basically, I'm heating through match stick and also through hot vess
Peltier devices produce electricity in proportion to the difference between one surface and the other. Even if you cool one side and heat the other you are unlikely to get enough power to run a 12V fan.

I assume you are using a typical 30x30mm cooler. There is little possibility of running anything useful from the power it would produce, and in any case, you will always have to use a great deal more energy to produce that little bit.
Generally,how many volts can peltier produces when it being heated?
 

Tonyr1084

Joined Sep 24, 2015
7,991
I try to heat peltier device with 12v 0.18a dc fan.
The way I'm taking your comment is that you're trying to use a fan as a generator. If you're trying to use the fan to heat or cool the peltier from the energy it creates - that's not going to be enough power. I've seen a peltier flashlight, but it uses three LED's and doesn't produce much light. A fan draws considerably more power than an LED.
 

Thread Starter

Tom gayle

Joined Sep 20, 2021
84
The way I'm taking your comment is that you're trying to use a fan as a generator. If you're trying to use the fan to heat or cool the peltier from the energy it creates - that's not going to be enough power. I've seen a peltier flashlight, but it uses three LED's and doesn't produce much light. A fan draws considerably more power than an LED.
No,I didn't take fan as generator.i literally heat the peltier through fire.so that peltier can produce electricity.its my thought.
 

crutschow

Joined Mar 14, 2008
34,818
So measure the open circuit voltage of the Peltier when one side is heated and the other side cooled (you can't just heat the whole device), and also measure the short-circuit current.
 

Ya’akov

Joined Jan 27, 2019
9,264
Basically, I'm heating through match stick and also through hot vess

Generally,how many volts can peltier produces when it being heated?
You need to track down the datasheet for the particular Peltier device you are using. It will have information about the various capacities.

When a Peltier is used for power generation it is called the Seebeck effect rather than the Peltier effect which is the cooling.

The Seebeck effect produces tiny fractions of a volt per degree K in difference between the two junctions. If you can cool the cold side sufficiently and heat the other side in an ordinary flame (e.g.a candle) you can get as much as 5W from a PC heatsink caller Peltier. That is, about 5V at 1A. But the key is the cooling, which is not easy. If you can bootstrap a 5V fan to get it cooling the cold side, in principle, it could be run from a flame heating the hot side.
 

MrChips

Joined Oct 2, 2009
31,060
As already noted, heating a Peltier device does not generate electricity.
You need a temperature difference between the hot side and the cold side.
Unless you have a very large and stacked array of Peltier device, there is not sufficient power generated to even light a single LED.
 

Thread Starter

Tom gayle

Joined Sep 20, 2021
84
As already noted, heating a Peltier device does not generate electricity.
You need a temperature difference between the hot side and the cold side.
Unless you have a very large and stacked array of Peltier device, there is not sufficient power generated to even light a single LED.
So, should I cool one side and heat another side then will it produces ?
 

MrChips

Joined Oct 2, 2009
31,060
Okay but how can I make temperature difference practically ?
Put an ice pack on one side and heat the other side with a heat gun.
Or rest it on a hot plate or stove and put the ice pack on top.

Of course, it would take a lot more energy to achieve the temperature difference than the amount of energy extracted from the device.
 

Tonyr1084

Joined Sep 24, 2015
7,991
Okay but how can I make temperature difference practically ?
That's a good question.

If one side is stuck to a cold water pipe with thermal paste while the other side is exposed to a heat source - you'll get some production. If there's only a few degrees difference from hot to cold (or cold to hot, either way) it won't produce much power. The greater the difference the more power it can produce. But all devices have a limit to what they can do before they break down. So don't try using a blow torch to heat one side - you'll burn it up.

If you can imagine - - - a block of ice on the cold side and a candle on the hot side - you'll see some more significant production of power. But you ask for "Practical". That's not practical. But hopefully you get the idea.
 
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