[KingM]

I want to ask some advice of the tremendously knowledgable people on this site. I've got some experience with wood boilers, but I'm not an expert or an installer. I've written up my advice and experiences right here, and am hoping a few of you who know what you're talking about could take a look at it and give me any suggestions on things I might have missed or could add to make this more helpful.

Muchas gracias.

[ubercynicmeister]

I want to ask some advice of the tremendously knowledgable people on this site. I've got some experience with wood boilers, but I'm not an expert or an installer. I've written up my advice and experiences right here, and am hoping a few of you who know what you're talking about could take a look at it and give me any suggestions on things I might have missed or could add to make this more helpful.

Muchas gracias.

Hi King M (Is that a reference to one M. King Hubbard?)

I have JUST the contacts for you. You see, I've been fooling about with steam since I was in my teens, and now am a self-appointed expert on it.

OK, start small...what is it that you want to power? A 1200 MW steam turbine to be spun up to 3600 RPM and weighing in at several tons? In which case: FORGET IT.

Secondly: you correctly point out that the "emissions" from the traditional wood-fired set up were objectionable. What you DON'T point out is that the emissions were actually an awful lot of unburnt fuel or partially burnt fuel. This is objectionable when you realise that somewhere about 2/3rds of the fuel one stuffs in went striaght up the chimney / stack / exhaust.

So a very intelligent fellow by the name of Livio Dante Porta studied the problem and decided to use some traditional science to fix it.

He was studying steam locomotives (as I do) and realised that a very old method of making what's called "producer gas" could solve quite a few problems. What happens is that any form of carbon combustion (the best known is coal burning, but this applies even to something as awful to burn as bagasse) when exposed to steam will produce a very complex endothermic (heat-absorbing) reaction, yet will produce a burnable gas. In essence, you get two fires for the price of one. The heat absorbing reaction also increases the boiler's efficiency because the heat-absorbtion efficiency of a boiler is measured by the difference in the temperature of the steam to the exhaust gases. Lower the exhaust gas temp and your boiler automatically becomes more efficient.

Secondly - if one increases the length of "burn" of the flame, efficiency goes up. This is what the producer gas does and combines a burnable substance (the producer gas) with another burnable substance ( the "volatiles" as they are called) from the actual fuel over a vast source of ignition (the fire-bed) and you get a very long burn.

This means that the emissions are less than 10% opacity (that is they can barely be seen). If one uses (say) bagasse, which is the left-over of sugar cane refining, then one is having a carbon-neutral fuel, anyhoo, so the Greenies objections (BANANA: Build Absolutely Nothing Anywhere Near Anyone) can be mollified.

So, in essence, one can have wood-fired anything without the smoke & particulates - if one wants to.

In the steam locomotive application, one can build a steam locomotive that costs about 1/2 as much as a diesel, is at least twice as powerful as the best diesel, and costs 1/10th to run. And is very much better for the environment.

PLEASE BE AWARE If you intend to operate a boiler at over 30 PSI (Pounds Per Square Inch for the metricised) you WILL need a boiler attendant's certificate. Unles the boiler is mounted in a steam launch, in which case (in Australia) it sorta falls between the regulatory planks and then (for reasons I do not know why) you don't need a Boiler Attendant's Certificate.

Go figure.

In any case, I return to my original question: what the heck do you plan to do with it? If you are planning to generate electricity, then the work's been done for you, and here's a guy you should invest in:

Ted Pritchard's Homepage

[KingM]

Thanks for the input. The fewere emissions = more burned fuel is a good point.

The wood boiler is for residential heating and hot water purposes.

re: KingM. It's an old video gaming handle from way back when. King + M from my name, Michael

[hippiegunlover]

If you are writing this for someone with no knowledge of wood furnaces, then you need to point out that they can be used for either water (base board or radiators) or can be hooked up with a blower for a house with existing forced air ducts.

Also are you talking about an inside or outside wood furnace? An inside one might raise your insurance rates, but an outside one will probably lower them.

[WisJim]

Most outside wood boilers are inefficient and put out more nasty stuff in the smoke than inside furnaces or boilers, as they do not have to meet any kind of environmental regulations. And, to make it worse, lots of folks burn trash, garbage, tires, wet or treated wood, and other items that make the emissions even worse.

On the other hand, some of the inside boilers, such as Tarm and others, are surprisingly efficient. They could be set up out of the house in a small shed, etc.

We have never had any increase in insurance rates in our home, and we have always heated with wood--for the last 30 years at least.

[ubercynicmeister]

Thanks for the input. The fewer emissions = more burned fuel is a good point.

The wood boiler is for residential heating and hot water purposes.

Then you need not a "boiler", per se, but a Hot Water Service. This makes things IMMENSELY easier and one needs have no "quals" to run the darn thing.

The easiest way to think about it is to picture the way soalr hot water services are arranged. Please bear with me as I describe very badly how it's done:

A series of pipes or collectors heat cool water (in this case, using the Sun's warmth) and that rises to what's jknown as a header tank. The system cannot be too simple, because the weater will naturally cool, so one needs a "retunr" pipe, as it were.

Also, then the user turns the tap on, the water they want neeeds to be hot, so the system has to be arranged to allow the cool water coming into the system to displace the hot water (and thus push the hot water off to the user), not the cool water gets through to the user before the hot stuff.

This is making a meal out of it, but the piping arrangements can be followed for the wood-fired type of "stove" where the hot water is heated by the firebox and rises to a header tank where one uses it.

NOTE: if one has such water then a very fine spray (with a minimum amount of water) of water in underneath the fire-bed will reduce the emmissions drastically, but the amount of water needed for such is TINY. If one puts in too much, it'll put the fire out. If not enough, it'll have no measureable effect.

My own idea, and one I'd like to build shortly, (haa haa, yes, I know, now that i've said that, watch Murphy of Murphy's Law fame throw everything in my path - anything that can go wrong is about to go wrong) is to have an ash-pan filled with water. This will quench the ash as it fall out of the fire-bed, but also, it'll provide enough steam to be drawn up through the fire so as to reduce emmission to the right level, without swamping the poor ole fire.

Secondary (above the fire) air also needs to be supplied, but here one has to make certain it's heated and controlled properly. Too little, once again, no noticeable effect. too much, the fire goes out. This is no easy task to get that balance.

Note well: I am making more a of a problem out of it than needs be - I'd like to do some experimenting myself (Murphy's already liking the idea) on how to do the task easily and efficiently. But I haven't done so yet, and this will take a while to get up and running anyhow.

*sigh* as Calvin of Calvin and Hobbs fame said: "I am put on Earth to do a certain number of tasks...I am now so far behind I will never die."

re: KingM. It's an old video gaming handle from way back when. King + M from my name, Michael

[aflatoxin]

I have a book on building wood-fired furnaces and boilers. It is well written, and has detailed plans. I'll share if you are interested.