Posted: 14 - January - 2010 at 05:14 | IP Logged

you may want to figure 12 volt system that way you have battery/solar backup in case your power goes out.. in md most of those outdoor furnces have been band.. too many neighbor hood complaints during the spring summer fall seasons.

try www.teksupply.com they have alot of farm items and prices are very reasonable spray foam, pex tubing boilers etc.. just got new catalog tuesday.. lost of wish list items..

Posted: 14 - January - 2010 at 06:10 | IP Logged

What if you could find to old compressor tanks, weld one inside the other. I would think this would work as long as there is a considerable size difference between the two.

Another thought, I remember a old timer showing me a trick back when I first started welding. I had built a gas tank for my go-cart, well the seems didnt pass a pressure test, so he took the oxy\actly torch and brazed over my welds, never had another problem with leaks.

If the furnace is going to be below the level of the house, then a thermo syphon would work fine using the stainless coils insid ethe firebox as long as the storage tank inside the house was not more ten feet away and elvelated above the furnace. This is a problem with mine, my tank doesnt produce a full 40 gallons due to lack of evaltion. I plan on fixing that problem later.

well just some thoughts, from Bearscamp

Posted: 14 - January - 2010 at 15:49 | IP Logged

"I wonder if anyone ever ran a water cooled engine using wood  gas generating power and heating water at the same time??" 

Mother Earth News did a truck, (I got all the OLD copies) since a large percentage of energy in an internal cumbustion engine goes as waste heat, you would have a GREAT idea.

Another efficient burn idea I was looking at is "rocket" stoves.  Do a google on that or "tin can stove"  I saw one page that had scaled it up.

Posted: 17 - January - 2010 at 10:51 | IP Logged

Farm Show has featured Lister and "listeroid" dealers, I wasn't interested enough at the time to memorize prices.  I got about 5 years worth of back issues.  Farm Show webiste allows searching and list of articles but won't show articles, so If you are interested I can scan/send.  Some of MBN'ers have the cd version of Farm Show.

You probably already know this, but as I remember it, the story is that the Lister was made in England and some used in India.  Technology was simple enough that India started copy-ing them.

And going thru Farm Show looking for tractor repower ideas (replacing a tractor engine with anything other than OEM for that model) I saw an article on a wood-gas car.

Keep thinking and doing!  I believe innovation on these ideas come from backyard mechanics, not the big corporate "can't do that because we'll get sued, won't make money, can't, can't, can't...

Posted: 18 - January - 2010 at 06:59 | IP Logged

Farm Show has featured Lister and "listeroid" dealers, I wasn't interested enough at the time to memorize prices.  I got about 5 years worth of back issues.  Farm Show webiste allows searching and list of articles but won't show articles, so If you are interested I can scan/send.  Some of MBN'ers have the cd version of Farm Show.

You probably already know this, but as I remember it, the story is that the Lister was made in England and some used in India.  Technology was simple enough that India started copy-ing them.

And going thru Farm Show looking for tractor repower ideas (replacing a tractor engine with anything other than OEM for that model) I saw an article on a wood-gas car.

Keep thinking and doing!  I believe innovation on these ideas come from backyard mechanics, not the big corporate "can't do that because we'll get sued, won't make money, can't, can't, can't...

[/QUOTE]

Again all good information.  First I spent some time looking for scaled up rocket stoves and did not find them.  Also what kind of system would you use to stoke it?  Maybe auger wood chips in and ash out? 

I wasted a lot of time looking at Lister engines on Youtube they are neat.  Maybe not Bonneville Salt Flats neat, but generate you own power neat.

I have not seen the Farm Show Magazine before I think I will take their sample copy offer.

BTW I did see a GM V6 engine replace a 2 cyl John Deere engine.  I liked the Ford V8 flathead conversion for the 8N Ford Tractor.  Then again I really like the sound of the old flat head with dual glass packs.  OK now you know that I'm old.

It sure seems that most inovative ideas come from backyard mechanics.  After working in manufacturing for a number of years I came up with three rules why a company will change a product.  One, competition requires a change.  Two, the new way is cheaper.  Three the law forces them to change. Maybe we can also say they will change because they lost a lawsuit too.
I have another rule.  The cost accountent always wins.  Lets say engineering wants to improve the exhaust valve in a certain engine.  The cost account says it will oost 15 cents more per engine and we will lose $200,000 in parts sales per year if we improve the valve.  Guess which way management will go?

Posted: 06 - February - 2010 at 08:21 | IP Logged

Doc, I like the stone mass fireplace ideas too.  For some of us, we already have the house not designed for it.  I wish you very well in your plans!  So I'll try to answer Bob.  He may invent/build just what I need!

Bob B., I may not be reading your post close enough, I may see an error in design...  You mention a pvc condensing stage.  The regular flue temps from average furnaces is 350* or more.  Fossil fuels can create water/steam as they burn, and a wood fire burns the wood and steams off any moisture in the wood.  burning greener wood creates even more steam.  As you know, steam condenses at 212*  PVC can't handle that much heat.

So your heat exchanger to condense the steam to extract more heat might be best in stainless steel.  Are there other materials that can handle the corrosiveness and heat?

The storebought condensing furnaces use pvc at the outlet of the furnace because the temps are down toward 150*.

Otherwise, keep designing and planning, I think it could work, and when I get my projects caught up, I plan to do very similar to what you are!

Posted: 06 - February - 2010 at 09:39 | IP Logged

Thanks Doc!  I gots a lot more to study!  The plans I bought but haven't done anything with was to build a masonry burn chamber but somehow have the exhaust go up, out to a 2nd chamber where he used some A/C condenser coils with water in them, and somehow the exhaust re-entered the bottom of the burn chamber to be re-burned, and it had a flue at the back of the 2nd chamber.  It looked like either an endless loop or a bypass of the 2nd chamber...  The reason I did buy the plans w/o a good description was to explore the idea of a masonry burn chamber but capturing the heat with water.

Posted: 06 - February - 2010 at 18:27 | IP Logged

Another thing I meant to add is that pvc might not be efficient at transferring heat to the water...

Greg, I've read on Hearth.com that a couple of guys have copied a high efficient one like you describe.  But they had one avaible to copy.

I tried to copy/paste your link, and it looks ok, but not linking.

Been wondering how to get those two passes thru the chambers.

Without stealing copywrited stuff, I think it should be possible to home-design a something!  What if one could figure out that hot burn chamber, and firebrick could separate the burn from the heat exchanger (HX).  Maybe even build the burn chamber with masonry, and maybe embed the HX in the masonry like Doc says.  Of course the masonry (if outdoors) should be heavily insulated. 

One idea I'm toying with that masonry burn chamber to keep the fire hot and avoid steel costs+welding, but set a homemade HX on top.  Pass the flue gases multiple thru the HX, but my twist would be to plan on cooling the flue gas below condensing steam temp buy using stainless and condensate drain channels.  Would have to use a draft fan.