Thermocouple generators

[Thunderchild]

Now this is an idea that I have hosted since as a kid I saw the experiment portrayed in my school sience book. as I recall it was a copper and nikel plate joined together that when heated by a flame would generate power. is this practical and with what other metals can I do it. I presume that they can be connected in series so enven if one volt is generated I can make 12/13 volts by putting then in series.
well basically any comments and opinions are welcome. (apart from that I'm mad as I know that already :wink: )
:!: :?:

 

[Nigel Goodwin]

Now this is an idea that I have hosted since as a kid I saw the experiment portrayed in my school sience book. as I recall it was a copper and nikel plate joined together that when heated by a flame would generate power. is this practical and with what other metals can I do it. I presume that they can be connected in series so enven if one volt is generated I can make 12/13 volts by putting then in series.
well basically any comments and opinions are welcome. (apart from that I'm mad as I know that already :wink: )
:!: :?:

It generates EXTREMELY small volts and amps, you would need to put 100's (if not thousands) in series to make 12V - and the current from them would be miniscule.

They are usually used for temperature probes, the voltage they generate is directly proportional to the temperature.

One of the meters I have comes with such a probe, I've just tried it on the voltage range - with the probe in my hand it reads 26 degrees centigrade. Using the voltage range it shows 0.6mV.

The current ambient temperature it shows is 12.7 degrees, and at that the voltage reading is below the minimum resolution of the meter.

 

[Thunderchild]

OK now imagine that lil thing as say 100 sqcm of metal clamped together and heated to the many hudreds of degrees that would come from a fire (yes we still have a kitchen fireplace for the winter). as I recal from chemistry lessons on battery cells the voltage value is defined by the metal mainly and so by finding the one that is most - and most + u get a p.d. obviously this is also going to depend on the temperature in my application as well and so will the current. I pressume a similar logic is applicable in this case taking into accout the physical size of the juction and the temperature. the voltage had something to do with the chemical composition of the metals used

 

[Nigel Goodwin]

OK now imagine that lil thing as say 100 sqcm of metal clamped together and heated to the many hudreds of degrees that would come from a fire (yes we still have a kitchen fireplace for the winter). as I recal from chemistry lessons on battery cells the voltage value is defined by the metal mainly and so by finding the one that is most - and most + u get a p.d. obviously this is also going to depend on the temperature in my application as well and so will the current. I pressume a similar logic is applicable in this case taking into accout the physical size of the juction and the temperature. the voltage had something to do with the chemical composition of the metals used

The voltage is dependent on the temperature and the number of junctions in series. The current depends on the number of junctions in parallel.

Presumably?, by joining two plates together you would get more current? (might make uA's), but how do you join two plates of dissimilar metals together? - you also have the extra problem that this then becomes a bi-metallic strip, which bends when heated :lol:

 

[Thunderchild]

yes the mechanical side is quite complicated i would perhaps have to use a clamping system that would hold them together rather than bolt them directly and use ceramic discs for insulation. my main other querry is: if i increase the contact surface to say 100 sq cm (10 X 10) then would this not produce more amperage ?

 

[Nigel Goodwin]

yes the mechanical side is quite complicated i would perhaps have to use a clamping system that would hold them together rather than bolt them directly and use ceramic discs for insulation. my main other querry is: if i increase the contact surface to say 100 sq cm (10 X 10) then would this not produce more amperage ?

As I mentioned above, I presume so?, but not more 'amperage', only more 'micro-amperage'.

You might perhaps have noticed that this has never been used for generating electricity?. If you've got an open fire?, stick a kettle on it and use the steam to turn a small turbine and alternator - lots and lots more power, and lots and lots more efficient.

 

[Thunderchild]

true. yes i am considering steam as well

 

[Nigel Goodwin]

true. yes i am considering steam as well

Have you considered a clockwork generator?, as used in the wind-up radios? - it would certainly generate a LOT more power than thermo-couples are likely to.

 

[Thunderchild]

what do i sue as clock work ?
no shops for stuff like that here (S Italy - Black hole in the Blackest of black holes)

 

[Nigel Goodwin]

what do i sue as clock work ?
no shops for stuff like that here (S Italy - Black hole in the Blackest of black holes)

An old clock

What could be quite good is the mechanism from an old (very old) wind-up record player - if you could find one?.

What are you trying to do anyway?.

 

[Thunderchild]

i am trying to generate electricity obviously
i have no old clocks. perhaps steam is best i just need a boiler and turbine

 

[Nigel Goodwin]

i am trying to generate electricity obviously

Yes, that was blindingly obvious 8)

But to power what?, how much power are you looking for?.

Your thermocouple idea 'may' be able to dimly light an LED, if you could stack enough of them in your fireplace - but probably not much else?.

 

[Thunderchild]

I wish to generate ALL the power I can. as 12 volt car batteries are readily available and not too expensive I will try to make it into 12 volts or up it to that (another story) so as to be able to store it. I was actually thinking af putting a second battery in my car to collect "surpluss" current and use indors but do not want to take power from the rest of the car that only does short trips anyhow so it is not practicle.
i hope at least to be able to power from batter an UPS to power my computer

 

[zevon8]

How about making a cycle generator with an old excercise bike, or even regular pedal bike, driving a car alternator?

Exercise and lower your electric bill. :lol:

Search the net, many ideas are out there, here is one:

https://www.stewardwood.org/resources/DIYcyclepower.htm

There is also a member here doing a generator on a excercise bike, do a search for it ( I think it was williB )

 

[Thunderchild]

yes i have that idea a well. i can fix on a board an alternator and another roller or maybe another alternator and put the back wheel of my bike on top and pedal away to nowhere. i just have to get hold of a couple of alternators and lots of time. hehe
I have an old starter motor but that is not permanent magnets so i would have to exit it not to mention rewire it and prefer not to try. i have a second hand car pars shop near me for a propper alternator

 

[4electros]

principle

I think my friend that you shoudn't interest with the application of thermocoupler, much than the scientific concept itself....try to know more about the basic concept ...
Anyway that's only my viewpoint :lol:

 

[Nigel Goodwin]

yes i have that idea a well. i can fix on a board an alternator and another roller or maybe another alternator and put the back wheel of my bike on top and pedal away to nowhere. i just have to get hold of a couple of alternators and lots of time.

I would suggest a car alternator is rather large for driving from a bicycle, probably 600-700W? - as I mentioned in another thread, I seem to recall 100W is about the maximum sustainable output for a human driven generator.

 

[4electros]

new idea

Another idea that had appeared to me ! why don't you add one or two OP-AMPs to your thermocoupler so that you get high volatage gain thus high voltage output!

what's your viewpoint?! :idea:

 

[audioguru]

Re: new idea

Another idea that had appeared to me ! why don't you add one or two OP-AMPs to your thermocoupler so that you get high voltage gain thus high voltage output!

Duh! Sure, the opamp output could be voltage-doubled and used to power the opamp. Somehow!
Or you could power the opamp with a battery, then you won't need a themocouple.

Wouldn't it be nice if everything powered by a battery could instead be powered by the output of an opamp? And the opamp powers itself?

 

[bryan1]

Well a 100 watt 24 volt motor avaiable from **broken link removed** draws around 6 amps and thats only 1/2 the power used for a scooter what chance does your idea hold :?: I know a bloke who has a 200 watt motor on his bike along with 2-12 volt 12 amp hour batteries along with a home built alternator which is coupled to the chain drive. He reckons it fly's on flat ground but on any real inclines he has to pedal just to keep speed.
But it's a top idea for easy travel on a bike. But trying your Idea just doesn't stack up I'm afraid. I mean let's get real just use Ohm's law.