• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Is there any way to convert thermal energy to electricity?

Pavi98

New Member
Hello,

Currently I'm working on a project to convert thermal energy to electricity and store on a battery. I found it on the internet that Peltier Module can be used for this energy conversion? Is that possible in the long term use or is there any other possible way for this energy conversion?

Thank You
 

Les Jones

Well-Known Member
Most Helpful Member
A lot depends on the temperature and the temperature difference available from the source of thermal energy. I think in Iceland they use heat from volcanic activity to turn water into steam to drive turbines. (See https://en.wikipedia.org/wiki/Geothermal_power_in_Iceland )With other temperature differences it may be possible to use the same principle but with different working fluids. The Peltier module will work. A lot depends on the scale on the project.

Les.
 

rjenkinsgb

Well-Known Member
Most Helpful Member
I found it on the internet that Peltier Module can be used for this energy conversion? Is that possible in the long term use or is there any other possible way for this energy conversion?
It's possible to convert heat FLOW (ie. the difference in temperature between to parts) to electricity or, with a suitable mechanism, to mechanical energy.

A peltier module with a heat source at one side and a heat dissipator at the other will produce electricity.

A "heat engine" such as a Stirling engine, with the appropriate part heated and heat dissipated from another part, will produce mechanical energy or run a generator.

For sunlight as a source, you can use curved reflectors to focus more light and heat on to pipes to get high temperature water or other liquid & transfer that to a heat engine, or heat a low boiling point liquid and use it to run a turbine - then feed it through a condenser (heat dissipator) to allow it to change back to liquid; a refrigerator in reverse.

You can also use "heat pipes" for transferring heat in and out of devices - tubes lined with a porous material that acts as a wick for the transfer liquid (eg. alcohol) while the hot vapour travels the opposite way down the open centre.

Or just a closed loop pipe with gravity return for liquid in the lower part and vapour in the upper.
 

Pavi98

New Member
It's possible to convert heat FLOW (ie. the difference in temperature between to parts) to electricity or, with a suitable mechanism, to mechanical energy.

A peltier module with a heat source at one side and a heat dissipator at the other will produce electricity.

A "heat engine" such as a Stirling engine, with the appropriate part heated and heat dissipated from another part, will produce mechanical energy or run a generator.

For sunlight as a source, you can use curved reflectors to focus more light and heat on to pipes to get high temperature water or other liquid & transfer that to a heat engine, or heat a low boiling point liquid and use it to run a turbine - then feed it through a condenser (heat dissipator) to allow it to change back to liquid; a refrigerator in reverse.

You can also use "heat pipes" for transferring heat in and out of devices - tubes lined with a porous material that acts as a wick for the transfer liquid (eg. alcohol) while the hot vapour travels the opposite way down the open centre.

Or just a closed loop pipe with gravity return for liquid in the lower part and vapour in the upper.
Is the peltier module reliable to use? One module will produce maximum of 1V and is it possible to use two modules in series to gain much voltage to recharge a small battery?

Thank you.
 

rjenkinsgb

Well-Known Member
Most Helpful Member
A peltier effect generator, aka thermoelectric generator (TGR), will have a voltage defined by the size and number of junctions, and the load.

Example, an evolution of wartime "tea kettle" thermoelectric generators which gives around 20V off load (which would be DC, not AC as the description claims). The flame would pass through the centre, the fins are the heat dissipators.

I can't find any pictures of tea kettle type TGRs, but there is a reference to those and the above TGK-3 here:

A better example of the TGK-3
 

danadak

Member
Solar cells have a spectral response that includes infrared -

1623703990890.png

Not sure how effective/efficient it is though.



Regards, Dana.
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
The peltier technology is very inefficient, but it does have applications. Power source for space probes. A radiation heat source and a thermoeletric module.

Delta T is the big issue. The max I have seen is 60 degrees C. They can melt.
 

Pommie

Well-Known Member
Most Helpful Member
Delta T is the big issue. The max I have seen is 60 degrees C. They can melt.
This is true, especially if inadequate heat-sink is used. If you keep below 250°C then they tend to be OK, if you then keep the cold side at 50°C with an adequate heat-sink and fan then a decent amount of power can be generated. So, delta T can be (much) higher than 60°C. How much self heating will happen if you draw a large current is anyone's guess. I've always intended to getting around to working this out but it's another project waiting for me to get around to doing. My guess is that a much higher voltage will be produced and the same current can be drawn as at delta T of 50°C.

Mike.
 

Latest threads

EE World Online Articles

Loading
Top