Electricity from my Stove??

[Roger Gunkel]

OK so I know I am a total plonker, but here goes.

We were outside cleaning the boat today and as I watched the slight heat haze coming out of the chimney from the coal fire, I thought to myself 'what a waste, there must be something better to do with this surplus heat. Then this evening eating a meal I started thinking about how it could be used.

 

When I was a young lad, my dad, who was a bit of a dabbler in everything, soldered together a little tin boat. He then took a piece of very thin copper tube which he made into a small coil in its centre, with a tail coming out of each end. He soldered this assembly into the middle of the boat, with the two tails coming out of the boat at the stern, below the water line. In the middle of the coil he placed a piece of paraffin wax (like a piece of firelighter), lit it and I watched fascinated as the water was drawn through the lower tail, heated up in the coil and expelled out of the other tail as steam, pushing the boat along at quite a spead.

 

Supposing a thin copper pipe was coiled tightly around the stove pipe, with a water inlet at the lower end and the other end connected to some sort of impeller or turbine, would it be possible to produce enough pressure to run a lightweight low powered generator of some kind. I'm not talking about megawatts here, but just a trickle output. I seem to remember those little Mamod steam engines running some toy add ons and it must be possible to generate a lot more power than that from the heat produced by a stove.

 

Any ideas or thoughts from anyone?

Roger

[Supermalc]

I actually think it's a good idea Roger. I think you'd have to put the pipe inside the chimney to get enough heat, however small bore pipe with a small flow of water should give enough power to power a small light i.e. LEDs.

 

Last year I went halves with Roy on a couple of solar lights. On my nights on the boat, I just swapped them around, and had light enough to see when I had to get up to toilet etc.

[magnetman]

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...

[Roger Gunkel]

Perhaps its not such a daft idea then!

 

I did see a small steam powered launch going up the river a couple of weeks ago, the engine on that looked very small although it was pushing the boat quite fast.

I can't imagine it would need anything like that amount of power to drive a small generator. Someone with experience of miniature steam engines might be able to advise on whether enough steam would be produced from my idea to power a small engine and generator.

Roger

[Carrie]

Hi Roger - a fascinating idea!

When I discussed the idea of coiling thin-bore copper piping around my stove flue, to heat gravity fed water from a small tank on the roof, (the reverse of your idea, with a tap at the bottom and a return 'expansion' pipe), he worked out that I would need about 100 coils to obtain 3-5 litres of hot water. Actually, he gave me a very precise working out of volumes and copper bore and pressure (he's a physics and mathematics man), but I can't remember it all as it was Christmas and I'm a Brandy woman. I do remember that I would need a great deal of copper!

[magnetman]

You do have to scroll down a fair bit and this link might take some time to load if your not on broadband speeds but here

http://www.prestonservices.co.uk/generators.htm

there is a nice little wood fired steam driven battery charger for sale, and it is WW2 I think, not sure but if they could do that 65 years ago surely something can be done today!!

 

 

text for reference and to avoid the need to open the preston services page:

 

RICARDO

Military Radio Battery Charging Set

Single cylinder enclosed P.V. steam engine

Direct coupled to 6 Volt D.C. alternator.

Wood fired boiler.

Output 3-4 Amps ~ Wt 50 Kg.

A complete set, packed in a wooden crate.

One of several currently available

 

 

edited to add link, second line...

Edited February 1, 2007 by magnetman

[Roger Gunkel]

Hi Roger - a fascinating idea!

When I discussed the idea of coiling thin-bore copper piping around my stove flue, to heat gravity fed water from a small tank on the roof, (the reverse of your idea, with a tap at the bottom and a return 'expansion' pipe), he worked out that I would need about 100 coils to obtain 3-5 litres of hot water. Actually, he gave me a very precise working out of volumes and copper bore and pressure (he's a physics and mathematics man), but I can't remember it all as it was Christmas and I'm a Brandy woman. I do remember that I would need a great deal of copper!

 

Hi Carrie,

Your hot water idea is a good one I think, but I'm slightly puzzled by the physics. I was thinking about a very similar thing based on the old house system, pre circulation pumps. Coil your pipe round the the flue as you said, but have the water coming from your tank into the bottom end, as the water gets hotter, it would them carry on up the pipe, through heat rising, into an insulated holding tank, with an expansion return. The old house systems used to produce gallons of hot water, can't see why it wouldn't work on a boat.

 

As regards the steam engine/turbine idea, much smaller bore piping would hopefully produce steam rather than just hot water, to power the drive unit, and the water would then be condensed back out to recycle as steam again. Any loss in the system should be able to be topped up from the river/canal through a filter.

 

You do have to scroll down a fair bit and this link might take some time to load if your not on broadband speeds but here

http://www.prestonservices.co.uk/generators.htm

there is a nice little wood fired steam driven battery charger for sale, and it is WW2 I think, not sure but if they could do that 65 years ago surely something can be done today!!

 

Just about to look Magnetman!

Edited February 1, 2007 by Roger Gunkel

[Roger Gunkel]

Hi Magnetman

Fascinating site! As you say why not do it today, with modern materials and technology seems to me a small steam powered generator is definately a viable proposition. Whether run off a flue coil or purpose built boiler unit. Could be the ultimate green unit for boats- burn your old rubbish, paper, cardboard, wood, coal etc and produce your own power. Do you need a stove? How about an insulated boiler that produces steam for the generator, hot water for heating and washing and runs on multiple fuel for all year round use.

 

Perhaps we don't need boffins, just a good engineer.

Roger

[magnetman]

Hi Magnetman

Fascinating site! As you say why not do it today, with modern materials and technology seems to me a small steam powered generator is definately a viable proposition. Whether run off a flue coil or purpose built boiler unit. Could be the ultimate green unit for boats- burn your old rubbish, paper, cardboard, wood, coal etc and produce your own power. Do you need a stove? How about an insulated boiler that produces steam for the generator, hot water for heating and washing and runs on multiple fuel for all year round use.

 

Perhaps we don't need boffins, just a good engineer.

Roger

 

I think we need to rope Mr Daniel Hutch in on this one. Where's he gone?

[Supermalc]

http://cedesign.net/steam/turbines.htm

 

Small steam turbines can be made, as demonstrated here.

 

The problem with the reciprocating steam engine has always been efficiency, or rather lack of it.

 

However, as the heat source here is to develop radiated heat, if pipes were placed inside the stove, so in effect turning it into a boiler, and the pipes ran inside the boat, surely any 'lost' heat would only go to heating the boat, just as it did in the first place.

 

What I don't know is how much heat, and therefore steam would need to be generated to produce any usable power, even to power a small LED. And given the effort, cost involved, would there be anything to gain.

[Roger Gunkel]

http://cedesign.net/steam/turbines.htm

 

 

What I don't know is how much heat, and therefore steam would need to be generated to produce any usable power, even to power a small LED. And given the effort, cost involved, would there be anything to gain.

 

Hi Supermalc,

Given that my stove is rated at giving the equivalent of 5kw of heat output, that would seem to be more than enough to give quite considerable generating power. That would be particularly interesting I think, if, as you mentioned, the pipes were actually inside at the core of the heat.

 

Roger

[anhar]

...When I was a young lad, my dad, who was a bit of a dabbler in everything, soldered together a little tin boat. He then took a piece of very thin copper tube which he made into a small coil in its centre, with a tail coming out of each end. He soldered this assembly into the middle of the boat, with the two tails coming out of the boat at the stern, below the water line. In the middle of the coil he placed a piece of paraffin wax (like a piece of firelighter), lit it and I watched fascinated as the water was drawn through the lower tail, heated up in the coil and expelled out of the other tail as steam, pushing the boat along at quite a spead...

Hello Roger

 

Off topic somewhat but those toy jet boats are still made commercially, I saw a trader selling them at a boat show last year, Crick or Beale I forget. I had one as a kid that someone had given me and recall chugging it round the bath. It used solid meth. tablets.

 

regards

Steve

[Alastair]

A peltier device will give you a trickle charge off your stove. These are the same things used to power Eco fans.

 

If you google a bit, you'll find all sorts of commercial installations using them, often on remote sites - pipelines in the far north etc.

 

The Swedish military have one meant to sit on a Trangia meths stove, for recharging radios and the like.

[Alistair]

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...

 

I've been thinking about this as well.

 

The thermoelectric module in an Ecofan relies on a temperature difference to work.

 

That is there must be a hot side and a cold side to generate power.

 

Fortunately a boat in the water is surrounded by a large wet heatsink so welding something onto the shell of the burner (for the hot side) and onto the hull (for the heatsink) could produce appreciable power.

 

I've seen thermoelectric modules that can produce 40 watts from a temperature difference of 70deg C, so for instance two bits of cast aluminium with a module between them could produce as much power as a solar panel at just the time when you need it, i.e. when it's cold and dark outside and you've got the burner going...

[Hairy-Neil]

...... with modern materials and technology seems to me a small steam powered generator is definately a viable proposition. Whether run off a flue coil or purpose built boiler unit. .

 

This started out as a means of utilising waste heat.....Now you have progressed to the point of heating/lighting the whole boat from it its going to need specifically firing for the purpose, the concequence being the fuel costs will rise.......along with the wastage of heat due to the inefficiencies of burning solid fuel......

 

 

.............That would be particularly interesting I think, if, as you mentioned, the pipes were actually inside at the core of the heat.

 

There's a problem. You don't get owt for nowt.....If you start heating water with the pipes actually inside the core of the heat then either less heat will be radiated to the cabin, or more fuel will need to be burned to make up for the heat taken by the water....

[DaveR]

Finally as a thought on the original question - if you take too much heat out of the chimney pipe then there may not be enough hot air rising to maintain the fire. It would then require the ventilator at the front of the fire being opened, increase the temperature of the fire and consequently the chimney through an increase of fuel consumption.

 

Would it then be wasting the same amount of heat as it was before the heating coil was inserted? Back to the "owt fer nowt" routine I fear.

[Roger Gunkel]

Off topic somewhat but those toy jet boats are still made commercially, I saw a trader selling them at a boat show last year, Crick or Beale I forget. I had one as a kid that someone had given me and recall chugging it round the bath. It used solid meth. tablets.

 

regards

Steve

 

Iwant one!!

 

This started out as a means of utilising waste heat.....Now you have progressed to the point of heating/lighting the whole boat from it its going to need specifically firing for the purpose, the concequence being the fuel costs will rise.......along with the wastage of heat due to the inefficiencies of burning solid fuel

I don't think I expect to get something for nothing, but it would be a big step forward to maximise the heat output that is already being used. If I had to use more wood and or coal to produce heat, power, hot water etc from one unit, that would give me greater self sufficiency and less reliance on mains electric, diesel and gas. At the same time, I am not turning my back on the original suggestion of using the waste heat from the stove to give me lighting or power for low consumption units. If we can get a little more for the same outlay, or a lot more for a slightly greater outlay, thats fine with me.

 

 

I've seen thermoelectric modules that can produce 40 watts from a temperature difference of 70deg C, so for instance two bits of cast aluminium with a module between them could produce as much power as a solar panel at just the time when you need it, i.e. when it's cold and dark outside and you've got the burner going

 

Alistair,

Sounds interesting and its nice to find others thinking along the same lines. I'll do a bit of googling this evening when I've got more time.

 

Roger

 

Finally as a thought on the original question - if you take too much heat out of the chimney pipe then there may not be enough hot air rising to maintain the fire. It would then require the ventilator at the front of the fire being opened, increase the temperature of the fire and consequently the chimney through an increase of fuel consumption.

 

Would it then be wasting the same amount of heat as it was before the heating coil was inserted? Back to the "owt fer nowt" routine I fear.

 

You may be right, but I think that the hot air would still rise up the chimney far faster than the pipes would remove heat from it and you would be using some of the heat that would otherwise just be lost

Roger

[magnetman]

As I mentioned in my first comment, the ecofan looks interesting. I suppose the ultimate thing would be a Radioisotope thermoelectric generator but that's going a bit far there must be middle ground somewhere.

My stove currently does cooking, hot water, central heating and if it could provide a small amount of electricity that would be absolutely stunning, all fired by solid fuel, with wood as an option for free energy.

I'm not talking about perpetual motion or something for nothing I just like the idea of the reduction in reliance on a 3 pin socket or a fuel pump nozzle.

 

edit: what about double skinned flue pipe with a water jacket?

Edited February 2, 2007 by magnetman

[anhar]

Iwant one!!

 

Roger

Here you go:

 

Make your own

http://www.nmia.com/~vrbass/pop-pop/

 

Buy ready made

http://www.jesters.com/acatalog/Tin_toy_boats.html

 

and look for "pop pop boats". They are not dear. Somewhat ominously perhaps, their largest model is known as the Titanic!

http://www.jesters.com/acatalog/tin_toy_titanic.html

 

Steve

Edited February 2, 2007 by anhar

[bendyboat]

hi folks

as an alternative to placing copper coils around the chimney pipe on the boat do you think this would work.

As the chimney is about a 5 inch diameter why not place a 6.5 or 7 inch pipe over it like an outer jacket, utilising the full hieght of the straight pipe run, sealed at top and bottom and input cold water at the bottom and draw it of at the top, just like a back boiler in priniciple but more like an outer hot jacket in practice, would it get hot enough to fed a couple of rads if pumped around.

thoughts anyone

Edited February 3, 2007 by bendyboat

[Roger Gunkel]

My stove currently does cooking, hot water, central heating and if it could provide a small amount of electricity that would be absolutely stunning, all fired by solid fuel, with wood as an option for free energy.

I'm not talking about perpetual motion or something for nothing I just like the idea of the reduction in reliance on a 3 pin socket or a fuel pump nozzle.

 

edit: what about double skinned flue pipe with a water jacket?

 

We're talking the same language!

Roger

 

hi folks

as an alternative to placing copper coils around the chimney pipe on the boat do you think this would work.

As the chimney is about a 5 inch diameter why not place a 6.5 or 7 inch pipe over it like an outer jacket, utilising the full hieght of the straight pipe run, sealed at top and bottom and input cold water at the bottom and draw it of at the top, just like a back boiler in priniciple but more like an outer hot jacket in priniciple, would it get hot enough to fed a couple of rads if pumped around.

thoughts anyone

 

I'm sure it would, but I think that if it is just the hot water for rads that you are after, it be be a lot simpler just to put a conventional back boiler on your stove.

Roger

[Roger Gunkel]

Here you go:

 

Make your own

http://www.nmia.com/~vrbass/pop-pop/

 

Steve

 

Thats brilliant Steve,

Whilst waiting for my Titanic to arrive from India, I am at this very moment wrapping vast swathes of copper tubing around my Evergreen stove, and drilling two holes in the back of the boat ready to 'POP' down the river in a steamy haze. The Isuzu will be chucked in the river at daybreak!!

Roger

 

 

 

Alastair and Alistair

There is some fascinating stuff out there. I found this US site which is very interesting. http://www.hi-z.com it would seem that making up a system with a couple of their more powerful units at $189 each, clamped to a stove and heatsinked to the hull, could yield up to 40 amps! Would take some ingenuity but not impossible. Would seem to have more potential than solar panels just when you need it in the Winter.

Edited February 3, 2007 by Roger Gunkel

[Hairy-Neil]

I'm sure it would, but I think that if it is just the hot water for rads that you are after, it be be a lot simpler just to put a conventional back boiler on your stove.

 

 

But be aware that it will burn more fuel heating the water for the rads.

[Roger Gunkel]

But be aware that it will burn more fuel heating the water for the rads.

 

Totally agree, but it will be cheaper than running your rads on diesel, which in my experience with diesel heating can get very expensive for liveaboards.

Roger

[magnetman]

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.

Edited February 3, 2007 by magnetman