HEAT to electricity conversion...

[HIREN DAVE]

Hi,

I want to convert heat to voltage. My temperature is around 25'C to 50'C..

is their any device that can generate sufficient voltage w.r.t. temperature??

 

[misterT]

What is sufficient voltage for you?

 

[jpanhalt]

If you discover a way to do that efficiently, you will be a very rich man.

Look into Stirling engines. Yahoo has a group. Here's another: https://www.thehotairengine.com/

A lot of hot air, but very little of note.

John

 

[lipschutz]

could you please clarify if you want to convert temperature into voltage or heat into electricity? obviously in nuclear reactor heat is converted into electricity, or a generator that run on diesel does nothing different than converting heat into electricity. or that you want a sensor that converts temperature into voltage output. in what context you are thinking? clarify.

-lipschutz

 

[tcmtech]

Read up on Peltier cooler devices. They can run backwards to change heat into electricity.

The efficiency is rather low though and power output is largely dependant on how large of temperature differential you can generate across the device.

 

[jpanhalt]

could you please clarify if you want to convert temperature into voltage or heat into electricity? obviously in nuclear reactor heat is converted into electricity, or a generator that run on diesel does nothing different than converting heat into electricity. or that you want a sensor that converts temperature into voltage output. in what context you are thinking? clarify.

-lipschutz

Do either of your examples work efficiently at 25 to 50 °C?

John

 

[lipschutz]

Do either of your examples work efficiently at 25 to 50 °C?

this is why it is to be clarified. efficient conversion of heat energy rarely(if ever) take place at such low temperature. whether it is a matter of useful production of power or just a sensor concern? to me the problem sounds more like the later one.

 

[crutschow]

For temperature measurement without any required bias current, thermocouples are typically used. They generate a small voltage proportional to the temperature.

 

[Externet]

Hi,
I want to convert heat to voltage.

Study the Seebeck effect

My temperature is around 25'C to 50'C..

Temperature is not heat. What enables generation is not heat only, but heat differential.

is their any device that can generate sufficient voltage w.r.t. temperature??

Sufficient means nothing; What is w.r.t. ?
Devices that use the Seebeck effect are called thermoelectric generators. Power the rover Curiosity on Mars.

 

[misterT]

Study the Seebeck effect

I am a fan of the EEVblog and Dave did an episode about thermocouples. I think he demonstrates the Seebeck effect quite well: https://www.youtube.com/watch?v=AYblSfpKRUk

 

[HIREN DAVE]

thanks to all for replying me....
It's my mistake that i didn't mention clearly...

The thing is, I want to developed such system that can provide good coolness in hot temperature. I am from India and here the temperature is between 10'C to 45'C. So i am searching for device that can give electricity without taking power supply.. For that reason i searched for thermocouple but it's not giving sufficient output. so any other device or idea to implement such application without use of solar cell...???

 

[jpanhalt]

To generate any energy/electricity, you must have a temperature differential. For example, if everything is at 45°C, even a thermocouple will not give a voltage.

So, what will be your source of coolness or additional heat?

John

 

[Externet]

A pedal air conditioner should work, or build one of these Stirling engines as big as a house; or bigger, and drive an air conditioner compressor with it :
https://www.youtube.com/watch?v=6DBktwPf3rk

 

[rmn_tech]

Out of idle curiosity. Does anyone know what voltage and current is generated by the thermocouples that are used with gas pilot flames? These thermocouple units actually drive a solenoid that opens the gas supply to the unit. (hence the reason you need to keep a button pressed for a while when lighting the unit) Obviously if the pilot goes out the solenoid drops out so cutting off the supply. I just wondered what the thermocouple produces I cant see it being a large amount of power, so what type of solenoid would be used?

 

[jpanhalt]

Out of idle curiosity, why don't you look it up instead of hijacking this thread. The original poster is not talking about a flame detector.

 

[MrAl]

Hi,

What you want is a thermopile not a thermocouple. A thermopile is a bunch of thermocouples connected together in series or series parallel. They are used on space craft to generate electricity from onboard thermal reactions.

But the problem is, just like thermocouples they do not work on the principle of temperature, they work on temperature differential. For example, a wire that is heated at one end and kept cool at the other end develops a voltage across it's length, but if the wire is heated uniformly from end to end it does not generate a voltage.

What this means is that if you did use a thermopile you'd have to find a way to have one end (or side) heated more than the other. For example, if you had a box with two ports in it one end of the thermopile could be exposed to the sun but not the wind while the other end could be kept damp with water and exposed to the wind but not the sun. So one end would be cooler than the other at all times.

The only trouble is it sounds like you are looking for MUCH more energy than you can get from these things without resorting to some sort of nuclear reaction, so i have a feeling this wont work anyway.

Your best bet here is solar energy using solar panels to generate the current to charge batteries and draw the power from the batteries when needed. Depending on the power needed however this can get expensive, so it depends how bad you really need it...life support or just hobby electronics

 

[audioguru]

We don't live in an oven like you do but most of us use an air conditioner to cool our homes in summer. The electricity to run the air conditioner is inexpensive and rarely fails. Even our ordinary cars have air conditioning.
I haven't been on a bus for about 45 years but today I think they are also air conditioned.

 

[DragonForce]

I am a fan of the EEVblog and Dave did an episode about thermocouples. I think he demonstrates the Seebeck effect quite well: https://www.youtube.com/watch?v=AYblSfpKRUk

David Jones is a genius! Glad to see another EEVblog fan

 

[lipschutz]

hi

So i am searching for device that can give electricity without taking power supply..

you want to transform heat energy into electrical energy and it seems you are not very sure of temperature differentials because ambient temperature is pretty much constant which doesn't give useful energy whatsoever. rather you want to lower your temperature by doing so. please read 2nd Law of Thermodynamics, Entropy and Carnot Engine in any standard textbook. that will provide you with sufficient insight.

lipschutz

 

[rmn_tech]

Out of idle curiosity, why don't you look it up instead of hijacking this thread. The original poster is not talking about a flame detector.

Oh so other people can talk about thermocouples just not me. As the subject of thermocouples had already been brought up, my post was as much on topic as other posts regarding thermocouples. I was not talking about a flame detector either, my question (adding to the discussion) was about THERMOCOUPLES. The OP was asking about producing electricity from heat.

Out of idle curiosity have you nothing better to do than insult me?