Log burner power

[Pretty Funked Up]

I've been watching and waiting for these devices to become commercially available

heres 2 in action

 

Just waiting on a response from manufacturer on price.....

[WotEver]

Just waiting on a response from manufacturer on price.....

Make sure you're sitting down

 

Here's a picture:

 

Tony

[Pretty Funked Up]

Is it a pretty burner that, steel and wood only!

Also they state not to use coal as it would go too hot for the unit

The burner isnt part of the price, its just the TEG unit.

[OldGoldy]

Is it a pretty burner that, steel and wood only!

Also they state not to use coal as it would go too hot for the unit

The burner isnt part of the price, its just the TEG unit.

Interestingly, on their website for the 'Indigirka' CLICKY they use both the word 'firewood' and 'solid-fuel' and the spec covers both the stove and the generator

[Pretty Funked Up]

Its a special burner with space for the TEGs on both sides.

Isn't wood a solid fuel?

[bobbynell]

This technology looks really interesting, I'm surprised we don't see more of these units?

 

A bit of searching for "thermoelectric generator" gives http://www.tegpower.com/ - if the claims are valid then this would ve the perfect (winter) balance for solar panels, either on the stove or the engine?

[Pretty Funked Up]

Yes. I originally looked into this when I wanted to make my eberspacher power itself from the heat of the exhaust.

I was going to modify the silencer to accept TEGs, then use heat pipes (vacuum) to a plate on the hull for the cold side, it all works perfectly on paper, (pat. pending... hehe)

Got a solid fuel stove now but the idea hasnt gone away.

 

TEGs off the engine is a waste of time compaired to an alternator, but BMW have done a car without an alt. at all just TEGs on the exhaust = no loss of engine power to the alt.

hence a better 0-60 time

Edited October 29, 2010 by Pretty Funked Up

[Smelly]

I would be very interested to hear your manufacturer's reply... I've wondered before whether Peltier modules could be used for something more practical than an Ecofan.

 

Even 1A at 14.V would make a difference. The Peltier chips are dog cheap on fleabay...

 

Edit... I'd wonder about a system vented using wee computer fans with two wee vents in the gunwhale to blow cold air across the heat sinks.

 

How would one bond it to the burner?

Edited October 29, 2010 by Smelly

[Pretty Funked Up]

Edit... I'd wonder about a system vented using wee computer fans with two wee vents in the gunwhale to blow cold air across the heat sinks.

 

How would one bond it to the burner?

 

exhaust:

If you live on a boat theres no need for heatsinks or fans as you have a steel hull and a canal

 

log burner:

one would simply sit it on the top of the burner, side mounted is better though if you can achieve it

 

The manufacturers got back to me with the immortal words:

"the price depends on how many units you are looking to buy, tell how many you want and we'll get you the price."

Edited October 29, 2010 by Pretty Funked Up

[Smelly]

exhaust:

If you live on a boat theres no need for heatsinks or fans as you have a steel hull and a canal

 

log burner:

one would simply sit it on the top of the burner, side mounted is better though if you can achieve it

 

Surely improving the heat gradient across the module improves output. Vents from outoors and a bit of Heath Robinson pipe work behind the fire wouldn't be difficult to arrange...

 

I'm very likely to buy some of these, probably 4 136w units when I get back from the pub... and sit them atop the fire. Have you found a decent datasheet that explains what I can expect to get out of them.

 

99p each...

[Pretty Funked Up]

Surely improving the heat gradient across the module improves output.

 

I'm very likely to buy some of these,

99p each...

 

the bigger the heat differential the more the output.

 

be careful as there are alot of different types, mainly in construction materials. Some cant handle the heat and will literally de-solder themselves. If theyre 99p theyre most likely a pile of ..... errr..... ummmmmm

[bobbynell]

I'm finding this really interesting now. Taking it to individual applications, this company is producing lots of things that mount on radiators, pipes etc http://thermalforce.de/engl/product/module/index.php

 

Keep scrolling down and there's all sorts for stoves, gas cooker ducts, heat exchanger etc etc (can't see prices mind).

 

Is there some major catch that I'm missing? If I can use this technology I'm convinced it will answer the winter lack of solar PV energy.

[bag 'o' bones]

I assume the battery is mounted underneath....................

[Smelly]

The deed is done, 40 quid.on modules and heatsinks with a total rated capacity of 36 amps;.I hope they're nowhere near their rated capacity as I'll need to upgrade the cable run...

 

I'm not too worried about their getting too hot as.there's a backboiler in and the fire already struggles to boil a kettle.

 

I'll hardwire my ammeter against one to see what the output is and.report. in. Don't hold any breath though as I'm on 14 day delivery...

[luctor et emergo]

Interestingly, on their website for the 'Indigirka' CLICKY they use both the word 'firewood' and 'solid-fuel' and the spec covers both the stove and the generator

 

 

from the above mentioned website:

 

Five out of 21 million dachas (summer cottages) in Russia either do not have power supply at all or often experience power failures.

 

That doesn't look like a massive amount of ill supplied Dachas to me.

 

Me finks, that the translation may have lost something here and there.

 

[blodger]

The deed is done, 40 quid.on modules and heatsinks with a total rated capacity of 36 amps;.I hope they're nowhere near their rated capacity as I'll need to upgrade the cable run...

 

I'm not too worried about their getting too hot as.there's a backboiler in and the fire already struggles to boil a kettle.

 

I'll hardwire my ammeter against one to see what the output is and.report. in. Don't hold any breath though as I'm on 14 day delivery...

I am following with interest and have been looking at the peltiers offered on Ebay, not got as far as heatsinks yet; Care to name which suppliers you have thought best?

[Smelly]

I am following with interest and have been looking at the peltiers offered on Ebay, not got as far as heatsinks yet; Care to name which suppliers you have thought best?

 

I'm on my phone so excuse me not linking.

 

I've bought the 99p Chinese peltiers as if they go fits up it's not too much of.a.waste and the.$5 copper heatzinks.

 

I'm probably going to test the first one with.a bulb to see how.the.voltage does and to prevent the fire turning into a fridge I'm thinking diode.thoughts, possibly zeners.

 

I like the idea of a.switch parallel to the diode so I can chill my beer in the stove...

 

I don't know yet whether the peltiers will mind being open circuit while hot or what voltage I. Can realistically expect or indeed what effect wiring them in series might have if needs be.

[bag 'o' bones]

Having done a fair amount of research on the subject of peltiers, there is a big discrepency between the theoretical output and what you can actually achieve.

 

In summary:

 

Whilst the rated watts quoted by the seller may be say for arguments sake 50 watts output, they hardly ever mention amps. Probably because on averge the amps are in the milliamps range i.e. not exactly very useful.

 

The amount of juice available rely on there being a large temperature diffrence between the hot side and cold side. In other words you need a very large heat sink with maybe a fan. Fans require to be powered by electricity, the same electricity being produced by the peltier!

 

Read up on thermodynamics particularly entropy. Simplistically the reason why peltiers are very efficient when powered from an external power source to produce cold - the main application - but very inefficient when wired in reverse to produce electricity.

 

Peltiers soon break down if subjected to excessive uncontrolable heat, as in attached to the side of a log burner.

 

I could be wrong i'm not an expert but from what I can make out peltier technology is a very inefficient method of producing power for anything more than illuminating an LED.

[blodger]

I'm on my phone so excuse me not linking.

 

I've bought the 99p Chinese peltiers as if they go fits up it's not too much of.a.waste and the.$5 copper heatzinks.

 

I'm probably going to test the first one with.a bulb to see how.the.voltage does and to prevent the fire turning into a fridge I'm thinking diode.thoughts, possibly zeners.

 

I like the idea of a.switch parallel to the diode so I can chill my beer in the stove...

 

I don't know yet whether the peltiers will mind being open circuit while hot or what voltage I. Can realistically expect or indeed what effect wiring them in series might have if needs be.

From reading it seems a 100 deg diff of temp from one side to the other is needed to get a decent voltage and then as generators it would appear that 8.8v would be good (not 12v)so I am thinking two in series with similar in parallel to see what amps. Internal resistances disfavour series connections from what I have read so I do not know whether the commercial products use voltage doubling in their regulators as well. Not ordered anything yet; still gathering info.

[Smelly]

B'o'b 1 amp for 24 hours would be worth it...

[blodger]

B'o'b 1 amp for 24 hours would be worth it...

I've ordered 5 136w high temp peltiers, an ali heat sink, some 2mm Cu plate and some heat paste.

 

Already have some computer fans and diodes; What else will I need?

[Justme]

I've ordered 5 136w high temp peltiers

 

 

I assume thats 136w of HEAT handling capacity not 136w of electrical production?

[blodger]

I assume thats 136w of HEAT handling capacity not 136w of electrical production?

No that's how much energy they would consume if the peltiers are wired up for cooling or heating. You only get a fraction of that when using them in reverse for power generation; It remains to be seen what DIY can do but there are now commercial products being manufactured that give worthwhile outputs from waste heat, hence the interest

 

Edited to add they only cost about 2.50 each inc P&P so worth a play

Edited October 30, 2010 by blodger

[Smelly]

No that's how much energy they would consume if the peltiers are wired up for cooling or heating. You only get a fraction of that when using them in reverse for power generation; It remains to be seen what DIY can do but there are now commercial products being manufactured that give worthwhile outputs from waste heat, hence the interest

 

Edited to add they only cost about 2.50 each inc P&P so worth a play

 

Worth a play... I've managed to blag a fancy probe thermometer so will be able to keep an eye on the temp diffwretial.

 

I've seen figures citing 5% efficiency so if it works I'd hope.for about 1.5 amps which over a day is the equivalent of an hour's engine running. I might yet buy another couple .

 

I've spotted a bloke who's using them in series so there's hope for generating enough voltage.

 

I'm wndering about using just one fan and some ducting.

[blodger]

Worth a play... I've managed to blag a fancy probe thermometer so will be able to keep an eye on the temp diffwretial.

 

I've seen figures citing 5% efficiency so if it works I'd hope.for about 1.5 amps which over a day is the equivalent of an hour's engine running. I might yet buy another couple .

 

I've spotted a bloke who's using them in series so there's hope for generating enough voltage.

 

I'm wndering about using just one fan and some ducting.

 

I'm looking at sandwiching four, they are only 40 mm square + wires, between some 2mm copper sheet and an ali heatsink that's 112 x 83mm. I am initially looking at fixing a computer fan to the fins and maybe piggybacking another but perhaps I'll have to concoct something so they are side by side. Might work better than the ecofan!

 

My stoves a Villager Heron and the flat top extends over the sides enough to drill a couple of holes for fixing etc