Electricity from my Stove??

[Roger Gunkel]

WOW!......

 

 

Now these DO LOOK WIKIDLY INTERESTING

 

http://www.hi-z.com/

 

edited: I don't mind burning more coal, I buy it from the coal boat and the more I buy from him the more likely he is to remain in business which helps me and gives the canal more character (Peter Hawkers boats are superb I reckon). I'd much rather be reliant on solid fuel than liquid fuel and as I don't run a diesel generator it's petrol I'm trying to replace anyway. If a system could be made to work running off the stove trickle charging the batteries that'd be the best thing ever I reckon.

 

Found quite a few companies making these thermo-electric devices on the net, but this was the only one that I had a real chance to look before the eyelids got heavy. Certainly an exciting looking direction to explore and doesn't look to be that expensive. I'm surprised no one has really picked this up before especially as the eco fan has been around a while.

Roger

[magnetman]

Here they have a 1950's radio power supply driven off the heat from a paraffin lamp

 

http://www.dself.dsl.pipex.com/MUSEUM/POWE...rmoelectric.htm

[Roger Gunkel]

Is it just me, or is this REALLY EXCITING STUFF!!

Roger

 

PS Here's another to wet your appetite

http://freeenergynews.com/Directory/Thermo...tric/index.html

Edited February 3, 2007 by Roger Gunkel

[Supermalc]

Reality check ....... not trying to 'rain on your parade' far from it.

 

As Neil has pointed out, you don't get something for nothing, however you can limit, or use the waste, and solid fuel stoves are very inefficient.

 

An engine, diesel or petrol is simply an energy converter; it converts heat to mechanical energy. An internal combustion engine is more efficient than an external combustion engine (a steam engine) although I don't think they have made them better than 35% efficient (I could be wrong, as I've not read many modern articles)

 

So all you can do is try to limit the waste, either radiated, conducted, or mechanical.

 

The question you have to ask is, how much energy, resource and cost does it take to make use of the waste heat (energy) and is it worth it.

 

Some people maintain the materials and energy required to produce wind farms, far exceeds any benefits from the energy produced over their lifespan.

[John Orentas]

http://www.dself.dsl.pipex.com/MUSEUM/POWE...rmoelectric.htm

 

 

Fantastic site:- Narrowboat started to get boring, nothing better that nut-case inventors, Monowheels, fantastic vehicles.

Did I ever mention my mates Acme cordless electric fires and irons ?

[Roger Gunkel]

Reality check ....... not trying to 'rain on your parade' far from it.

 

As Neil has pointed out, you don't get something for nothing, however you can limit, or use the waste, and solid fuel stoves are very inefficient.

 

An engine, diesel or petrol is simply an energy converter; it converts heat to mechanical energy. An internal combustion engine is more efficient than an external combustion engine (a steam engine) although I don't think they have made them better than 35% efficient (I could be wrong, as I've not read many modern articles)

 

So all you can do is try to limit the waste, either radiated, conducted, or mechanical.

 

The question you have to ask is, how much energy, resource and cost does it take to make use of the waste heat (energy) and is it worth it.

 

Some people maintain the materials and energy required to produce wind farms, far exceeds any benefits from the energy produced over their lifespan.

 

Certainly not raining on my parade Malc! Watching all the waste heat going up my chimney has got me thinking and researching. I agree with you about not wasting money and energy on trying to save small amounts, but the Eco fan has shown that you can use some of this waste usefully. All I am doing is looking to see what is possible, rather than being pessimistic about it all. If you haven't looked at some of the sites, take a look, it is certainly interesting. All we need is someone developing the Eco fan and perhaps steam technology into a wider area. If I can use 35% of my waste heat I will be delighted.

Roger

[Theo]

I suspect that in the relatively near future a heat powered generator system will become a best seller for canal boats. Probably needs some serious boffins looking at it in a real way but it's just GOT TO BE THE WAY I reckon. The ecofan is an example of thermosomething. Better not dig myself into a deeper hole...

 

 

It's the thermoelectric effect and I would think that they use a thermopile. (Lots of units connected in series)

 

Nick

 

It's the thermoelectric effect and I would think that they use a thermopile. (Lots of units connected in series)

 

Nick

 

 

No one has mentioned a stirling engine yet.

 

NIck

[bendyboat]

hi folks

there is no doubt the subject matter is fascinating and the opinions varied and wide,i wonder if anyone with the necessary knowledge would be prepared to extrapolate and describe what an apparatus would look like if it were designed for a narrowboat utilising the solid fuel stove and the surrounding cold water as a producing medium with the requirement to produce say 15 amps ,just for fun you understand

[Supermalc]

I'm with you all the way Roger. I have spent many many hours discussing energy issues with friends. In the 70s we were talking about heat from quicklime embeded in gable ends, that would be watered by rain, and dried by the sun. Just as an example.

 

Personally, I still feel some sort of turbine, either attached to the side, or in a 'torbedo, tube' is a very unexplored source of energy. Moored at a Lock say, there is flow everytime the lock is used. Moor on a tidal river, and there is flow most of the time. This is FREE energy, which means every drop extracted is a bonus.

 

I absolutely agree with you about the heat going up the chimney, but rather than trying to make a turbine to get extra energy, some sort of heat exchanger, with the heat going back into the boat may be a better idea. I'm sure this is done btw. Just not enough experience of NBs and heating etc.

 

This way you should use less fuel, rather than more.

 

Energy is in the air, and water all around us. All we need do is to discover a way to extract it.

[John Orentas]

What Roger is attempting to do here is extract this last bit of energy from the fuel he is using, an age old problem, think of the most efficient system you can that involves burning fuel of some kind. A power station perhaps, whether coal burning, oil or even industrial/ household waste they are probably the most efficient machines yet devised but what is all the steam and vapour coming from the cooling towers, it is coming from the process of cooling, removing the residual or wasted heat from the system.

 

Diesel engines are not too bad in the scheme of things, but put your hand on the exhaust pipe and that skin tank, what is that all about, much of your very expensive diesel is just warming up the canal. The sad fact is that all our machines and contraptions are grossly inefficient, yes it is possible to make use of that last bit energy but at every turn to will run into diminishing returns, do you really expect your very unsophisticated cast iron stove to be better that a power station. That last bit of heat coming out of the chimney, put your kettle on it an pre-heat your next pot of tea.

[Guest]

Not quite on topic, but I lit the fire on the NB today and had a play around with a desk fan that I have obtained. Just a few watts off the inverter and it really shifts the heat to the back of the boat, I was well pleased, and it was free. Should keep us cool during our increasing summer temperatures also. I'll be damned if I will pay £70 plus for an ecofan.

[Roger Gunkel]

Not quite on topic, but I lit the fire on the NB today and had a play around with a desk fan that I have obtained. Just a few watts off the inverter and it really shifts the heat to the back of the boat, I was well pleased, and it was free. Should keep us cool during our increasing summer temperatures also. I'll be damned if I will pay £70 plus for an ecofan.

The desk fan will certainly move the warm air down the boat, buts its not particularly economical. I agree about the £79 for an Eco fan, but we worked out a pretty economical way of doing the same thing as you by putting a 4" computer case fan at ceiling level, to blow the gathering heat from the stove down our boat. You can buy them in PC World for about £3.99 or any internet computer parts supplier for half that. They only use about 0.1 amps of 12v power and will run for thousands of hours. Ours has been running continuously and almost silently for 3 months and has been brilliant.

 

On other posts, its interesting to see the opposite sides of the coin. Those who are really keen to look at new ideas and be open minded and those who wring their hands saying it can't be done.

 

I can't undertstand that anybody seriously believes that burning wood and coal in a steel box and taking the produced heat straight up the chimney is a particularly efficient way of maximising that heat. Mine certainly keeps my boat warm but there is a vast amount of wasted heat coming out of the chimney. As for putting a kettle on the top of the chimney, whatever for? I already have a kettle on the stove all day producing a constant supply of hot water to save me wasting diesel in my Eberspacher or running the engine. I don't see myself piling loads more fuel in the stove to get this water. But inspite of my kettles of hot water, I still find the chimney outside the boat too hot to touch, so I don't see why anyone needs to be disparaging about investigating existing technology to better use this heat. I don't expect my stove to be more efficient than a power station, but if I can run one light bulb from the waste heat, then I am better off than I am now. If I find I can run 20 light bulbs, then I am much better off.

 

I have a friend who is a boat builder, engineer and open minded experimenter, so we are going to have a look over the coming months at some of the thermoelectric technology and see if anything workable can be constructed. I bet if it can, all the doubters will be lining up to buy. I imagine those who developed the Eco fan had their doubters.

 

The more I have been researching, the more I have found that this technology works to a lesser or greater degree within a wide range of temperatures. This would suggest that what works with a hot stove in winter, may well be applied to a hot steel roof in Summer, or perhaps even a hot engine!

 

Keep the comments and links coming, it may all be a waste of time, but so what I'm going to give it a go anyway.

Roger

Edited February 4, 2007 by Roger Gunkel

[Guest]

I wondered what sort of amperage an ecofan runs at? It would be interesting to know how much energy they actually generate. I must admit I have often wondered about solar water heating on the NB roof. The heat up there on a sunny day can be tremendous.

[magnetman]

Edited to say I have just re-read what I am commenting on and have edited my comments accordingly.

Edited February 4, 2007 by magnetman

[Supermalc]

Keep the comments and links coming, it may all be a waste of time, but so what I'm going to give it a go anyway.

Roger

 

Ideas are never a waste of time Hot engine, how about hot exhaust. I think it's 40% is wasted via the exhaust, which is where the turbocharger comes in. Usually with engines it's getting rid of heat that is the problem, but lengthen the exhaust with some type of double skin.....loads of usable heat, surely. Battery charging? Power, or lack of is one of the big drawbacks.

 

Just random thoughts.

[John Orentas]

To get useful energy from heat you need a reasonable temperature differential, an Ecofan works quite well because the top of a stove is around 200 deg but even then the amount of energy you get is tiny and remember it is not free either, that heat which the device cleverly turns into an electrical current to rotate the fan blades would otherwise be used to heat up your boat.

 

The temperature at the top of the chimney is quite low, probably no more than 80 deg. Collecting that energy and doing something worthwhile with it is not easy, just remember those cooling towers. On the other hand, best not to listen to discouraging voices I will follow progress with interest.

 

P.S. A turbocharger does not utilise waste heat but uses the otherwise wasted high pressure of the exhaust gasses, the heat is not used.

[Supermalc]

Yes, but John, where do the exhaust gasses get their pressure from ....... from heat that would otherwise be used to drive the pistons.

 

Fuel is burned to produce heat. Any heat that is not used to actually propel the vehicle, or generate the electricity etc. is therefore wasted. So the energy obtained to turn the turbochargers is in fact gained from heat not used for power.

[John Orentas]

Yes, but John, where do the exhaust gasses get their pressure from ....... from heat that would otherwise be used to drive the pistons.

 

Fuel is burned to produce heat. Any heat that is not used to actually propel the vehicle, or generate the electricity etc. is therefore wasted. So the energy obtained to turn the turbochargers is in fact gained from heat not used for power.

 

 

Hi Malc.

 

A turbocharger is driven by the high pressure of the exhaust gas, the fact that it is hot is incidental, the gas is pretty much at the same temperature when it enters the turbo as when it leaves it, another way of saying the heat doesn't do anything. Even the driving of the pistons, the heat doesn't do it, it is the rapid expansion of the gas that does the work, we have to go to some trouble to get rid of the heat.

 

Hard to think of any form of energy that was not in the form of heat at some stage, turn a light on in your house, that electrical energy was derived from burning a lump of coal 50 miles away.

[Hairy-Neil]

P.S. A turbocharger does not utilise waste heat but uses the otherwise wasted high pressure of the exhaust gasses,....

 

And even that is not for free either. Some of the increased power produced is lost because the turbo is restricting the flow through the exhaust manifold......

[Supermalc]

Hi Malc.

 

A turbocharger is driven by the high pressure of the exhaust gas, the fact that it is hot is incidental, the gas is pretty much at the same temperature when it enters the turbo as when it leaves it, another way of saying the heat doesn't do anything. Even the driving of the pistons, the heat doesn't do it, it is the rapid expansion of the gas that does the work, we have to go to some trouble to get rid of the heat.

 

Hard to think of any form of energy that was not in the form of heat at some stage, turn a light on in your house, that electrical energy was derived from burning a lump of coal 50 miles away.

 

Hi John - If we could extract the heat before expelling the used mixture, then yes the turbo is driven by the energy in the moving air. But that energy is obtained from the expansion of the burning in the first place. So indirectly, not directly it is driven by the waste heat.

 

BTW do you know why most turbochargers are used? I do, as I helped make large ones for 16 years.

[Alistair]

To get useful energy from heat you need a reasonable temperature differential, an Ecofan works quite well because the top of a stove is around 200 deg

 

 

but even then the amount of energy you get is tiny

 

Hi John,

 

Thanks for your interest in this one.

 

I agree with your first assertion and think that the temperature difference you could get (and maintain) between your burner and your hull with some suitably-shaped lumps of metal is considerable.

 

This kind of shape: >-+-< with the thermoelectric module in the middle.

 

I don't agree with your second assertion, however. 'Tiny' depends on how much power you *need*: and if I can get as much power as one of my solar panels from something six inches by three with no moving parts then I start to get interested.

 

Better still when it nicely complements my energy demands: I need lights on in the evening and the fire's on anyway, so to power my lighting (fluorescents and LED) from a small solid-state module sounds ideal.

 

Any thoughts, anyone?

[Roger Gunkel]

While agreeing with what a number of people are saying about heat and energy not being free or 'Owt fer Nowt', I think that my original point and reason for looking at alternative energy sources is not just efficiency and cost, it is also about self sufficiency and centralization of energy. For instance, at the moment I have gas for my cooker, diesel for my engine and Eberspacher, coal and logs for my stove and mains for my general electricity and 12v charging.

 

I am not a fool, thinking that I can run everything by sticking a few electronics on my stove and not increasing coal/log consumption, however, I am becoming increasingly tired of the vagaries of marina shore power and its ever increasing cost, spiraling diesel costs, inconvenience of gas collection and its potential dangers and again costs. I do find that I can maintain good supplies of coal to keep my heating costs down plus I have access to large numbers of free logs and scrap timber. If I can find long term ways of increasing efficiency of the energy I consume by using new technology to generate power from my stove, hot roof, exhaust gases etc, then I really don't care if I put twice as much fuel into my stove or other form of boiler. I could burn free logs all day long if that is neccessary, because compared with running multiple fuel systems, the costs and reliance on supliers would be vastly reduced and my self sufficiency greatly increased. As Alastair says, he has his stove going anyway so why not use it to supply light as well and reduce the load elsewhere!

 

Finally, next time you walk on your roof in bare feet next Summer and rush off to put your sandals on, spare a thought for how much energy you would have to produce if you were heating that roof yourself. It would be nice to use some of that heat constructively.

 

Roger

[magnetman]

Finally, next time you walk on your roof in bare feet next Summer and rush off to put your sandals on, spare a thought for how much energy you would have to produce if you were heating that roof yourself. It would be nice to use some of that heat constructively.

 

Roger

 

Some kind of adaptation of a solar pond maybe: http://images.google.co.uk/imgres?imgurl=h...en%26safe%3Doff

 

works on the fact salty water doesn't rise therefore the heat can be kept in the water and not radiated to surrounding air, or something (don't ask me I don't even know how a lock works)

[AllanW]

Fascinating topic...

 

I'd not given this much thought before, but I've been doing a bit of net research on this. The idea of using chimney heat has been around nearly forever... The domestic Smoke Jack turned, for over 300 years, the roasting spits of Western Europe!

 

The thermoelectric (temperature difference) devices are Peltier chips. Actually peltier elements can heat, cool, or generate electricity when heated and cooled on opposite sides. It's the same effect, just the other way around.

 

I could post a lot of info here but you're probably better off looking at the source material yourselves:

 

http://www.halfbakery.com/idea/Chimney_20power

 

(Actually have a look at the ther links on this site - I like the idea of using a burning candle to power ultra-bright LEDs!!!)

 

http://www.peltier-info.com/info.html

 

Also of interest (when they get it in production...) is http://www.powerchips.gi/

 

IMHO Power Chips will be the 'next big thing' because for comparison purposes, a typical thermoelectric (Peltier device) generator has a Carnot efficiency of about 5-8%. A Rankine cycle generator, such as a gas turbine, has a typical Carnot efficiency of about 30%, while a diesel or petrol generator is only about 10-15% efficient in Carnot terms. Power Chips are projected to achieve 70-80% of Carnot efficiency.

 

(whew!)

 

For more on Carnot cycles see here: http://cloudbase.phy.umist.ac.uk/people/co...e/lecture15.pdf

<-- definately NOT bedtime reading but I found it interesting!

 

There's also in interesting looking link about a woodburing stove bolt-on here but I've not read the full text yet: http://linkinghub.elsevier.com/retrieve/pi...196890404001931

 

Allan

[Roger Gunkel]

Useful links Allan,

 

Guess who's selling Peltier devices? Good old RS Components. They are advertised as cooling modules with electrical input, but they look the same as the American ones which produce power from heat/cold.

Might get a cheaper one to experiment with. Heres the link:- http://rswww.com/cgi-bin/bv/rswww/searchBrowseAction.do?N=4294730151&name=SiteStandard&callingPage=/jsp/search/search.jsp&BV_SessionID=@@@@1691522608.1170695238@@@@&BV_EngineID=ccciaddkdhmkkflcefeceeldgkidhgi.0&cacheID=ukie&Nr=avl:uk

Roger