Naked Science Forum

General Science => General Science => Topic started by: Naufal the B. S. on 20/07/2009 06:36:16

Title: Thermal to Electricity Generator?
Post by: Naufal the B. S. on 20/07/2009 06:36:16

How can we make Thermal to Electricity Generator directly without steam and boiler?

I need it for my solar cell project (without photovaltic, because I cannot find it sad)

please... give me the clear diagram that to ease me, because, just now, I receive the diagram of the thermal to electricity generator, but I can't read it. Can someone help me to read it?

This is the link,
{Was that link SPAM? - very possibly. MOD}

Please... Help me!

Title: Thermal to Electricity Generator?
Post by: Mazurka on 20/07/2009 12:24:42

The obvious method would be some sort of stirling engine.  Lots of nice diagrams etc on wikipedia...

Title: Thermal to Electricity Generator?
Post by: exton on 20/07/2009 22:16:41

I would also recommend a stirling engine.

If you can't do that, my second recommendation would be a peltier junction; it's a semiconductor device that turns a heat gradient directly into electric current. You can buy them in computer stores (where they'll be called 'peltier coolers') or on ebay. On ebay and electronics websites they're often called 'peltier devices'.

Here's one such website where you can buy one:

http://www.apogeekits.com/peltier_device.htm

Title: Thermal to Electricity Generator?
Post by: Soul Surfer on 21/07/2009 09:08:17

Stirling engines are complex very high precision engineered devices.

The simplest way is to use thermocouples (metallic junctions between two dissimilar metals)  if you put a lot of them in series in a circle with the hot junctions near a heat source and the cold junctions well away from the flame you can generate a small amount of power.  I believe the russians designed an oil lamp powered radio receiver that way many years ago

This is just the same as peltier coolers run in reverse as above but it can use things found lying around like copper and iron wire.

Title: Thermal to Electricity Generator?
Post by: daveshorts on 21/07/2009 10:21:03

Because you can just use peltier coolers running the other way - heat flowing through the cooler produces electricity, and peltier coolers are becoming more standard, using them as generators is getting more standard.

Nuclear powered spacecraft are ususally powered using radioactive decay to produce heat and this heat flows through a thermal generator to make electricity. Probes such as the New horizons mission use this.

People are even suggesting using this sort of unit to generate electricity from low grade heat from truck exhausts.

Title: Thermal to Electricity Generator?
Post by: lyner on 21/07/2009 12:45:07

Stirling is a heat engine - just the same as any other. It is no more 'direct' than a steam engine or an internal combustion engine because the system will involve a generator of some sort

BTW, "Peltier used the other way" is called the Seebeck Effect and was found sometime before Peltier. It's what is used in thermocouples and thermopiles. It is used in gas heaters which use a thermocouple in the pilot light to drive a solenoid to keep the gas valve open. It turns off the gas when the pilot light goes out and the solenoid lets go.

Title: Thermal to Electricity Generator?
Post by: Naufal the B. S. on 22/07/2009 02:06:43

Is my diagram one of peltier device?

Have you open it?

If you have read it, can you teach me, how it works, and how to make it?

Title: Thermal to Electricity Generator?
Post by: Naufal the B. S. on 22/07/2009 12:09:36

http://reactor1967.fortunecity.com/tg.jpg

Hey, the link in the top isn't SPAM!!

Title: Thermal to Electricity Generator?
Post by: BenV on 22/07/2009 12:21:11

It may not be spam, but it's broken...

Title: Thermal to Electricity Generator?
Post by: Naufal the B. S. on 22/07/2009 12:39:40

have you open it?

Title: Thermal to Electricity Generator?
Post by: BenV on 22/07/2009 12:43:04

Assuming it's this:  http://reactor1967.fortunecity.com/tg.jpg that you're talking about, I haven't opened it, as it's broken.

Title: Thermal to Electricity Generator?
Post by: lyner on 22/07/2009 13:54:19

Quote from: Naufal the B. S. on 22/07/2009 02:06:43

Is my diagram one of peltier device?

Have you open it?

If you have read it, can you teach me, how it works, and how to make it?

Go to a scrap yard and find an old gas heater. There will be a small  probe-shaped object , with wires leading to it which is held where the pilot flame goes. That is a (Seebeck Effect) thermocouple. Heat it with a flame and you will measure a small voltage from it. It will produce a small current. Bung enough of these in series and you can use it as a source of power - not a lot.
A thermocouple (just like a Peltier device)  consists of a pair of junctions between dissimilar metals. Usually, you would use the Copper connecting wires and a length of wire of another metal (say Iron) between them. (You just clean the ends and twist them together vigorously with pliers to get a good contact). Heat one junction and keep the other junction cool and there will be an emf generated (a few millivolts, only). Use a series of Copper - Iron - copper - iron - copper . . . . . . lengths,  heat up the iron- copper junctions and cool the copper - iron junctions and you could get several hundred millivolts. Choose the right metals to get the best effect.
See http://en.wikipedia.org/wiki/Thermocouple (http://en.wikipedia.org/wiki/Thermocouple)

Title: Thermal to Electricity Generator?
Post by: Naufal the B. S. on 24/07/2009 11:41:00

Could you give me the easy diagram of it?

I'm not british or american. Because of it, I cannot understand your purpose whole

Title: Thermal to Electricity Generator?
Post by: lyner on 24/07/2009 15:35:33

Bad diagram but it shows what I mean. RED would be iron wire, BLACK would be copper wire.
Top junctions all heated and bottom junctions all cooled. Voltage measured will be bigger as more junctions are added. (You may get a higher reading with your meter set to read mA, rather than V)
[diagram=485_0]
Wires can be as long as you like - just keep the zig zags from touching each other. Ensure that each join is scraped clean so you get a good contact.

Title: Thermal to Electricity Generator?
Post by: lyner on 24/07/2009 15:37:29

R.A. exhibition for me next year?

Title: Kno3a
Post by: Naufal the B. S. on 25/07/2009 02:06:23

Thanks, very very lot for you!! [:-)]

Title: Kno3a
Post by: Naufal the B. S. on 25/07/2009 02:08:02

Sorry.
How it works, master!?
Curiousity