Wood burning stove questions

First of all, if he gets the smoke to go up the flue, all that will do is keep his own building from smoking up. It will stink your place up first.....

You're right that the flue is way too small. A 6" pipe is about adequate for maybe 3 - 5 sq. ft. of fire area. He has close to fifty sq. ft. To keep the same ratio, he'd need at least an eighteen inch flue, and a two foot flue would probably be better.

It is not necessary to have a damper in the flue, but he should have a way of controlling the air into the firebox.

You don't say what is on the other side of the block wall, but it needs to be a chimney that goes up ten to twenty feet. It is the hot smoke rising through this height that gives the furnace its draft...

Further, the metal of the tank probably isn't very thick and it won't take very long to burn through. I hope he has good fire insurance...

Jerry

Without wanting to sound too negative, isn't this just a little bit unfriendly toward the environment?

Maybe your neighbour could get some bbq forks and toast japanese whale meat at meal break time. ; )

r.

PS - Sorry I can't help with the flue sizing.

Good advice, the above changes would make it work outside. There is no way to open a fire door that large without letting a HUGE amount of smoke in the room.

I've seen a number of outside wood/biomass burners for pallet sized items. This solves the smoke and insurance issues. Generally the unit is a boiler and hot water is piped to the building to be heated.

A lower cost (inside the building) solution is to cut the pallets in three pieces, right down the cross slats, and use a much smaller burner.

Karl

All he needs is a var-speed input fan in the front to push in the air... It also make it easy to start the fire...

All he needs is a var-speed input fan in the front to push in the air... It also make it easy to start the fire...

All he needs is a var-speed input fan in the front to push in the air... It also make it easy to start the fire...

There is a site with a draft calculator that I have not tried, but seems to be up to date.

I would think he would want to add a secondary burn chamber too. These things reburn the smoke in a small chaber above the fire before it goes up the chimney. I have not done this, so I don't know how critical the ratios are regarding chamber size relative to the rest of the burn chamber or if you need to add extra oxigen in the secondary chamber, but it seems that if you put in a flue thermometer with a way to regulate the intake you'd be able to sort that out pretty quick.

Bob

With a firebox that big with a lot of wood in it, he will probably have to close off the combustion air a lot. This will make it smell even worse since the fire will be smoldering. I think his problems with the neighbors has just begun. Of course there will be lots of creosote (pyrolignious (sp?) acid. This means dirty chimney, so he needs to prepare for a chimney fire now and then. Elbows in a smoke pipe add a lot of air friction and are not desireable. He wants about 0.05 inch water column of draft. You can get a draft gage for about $20 at an HVAC supply place. In case he didn't know, if the chimney gets below about the boiling point of water, then creosote forms heavily. We made maple syrup for 10 years using wood heat. Our goal was to keep the flue at 550 to 750 degrees. At these temperatures, we have never needed to clean the chimney. There are a number of external biomass furnaces in our rural area and you can quickly tell if its a warmish day by the unpleasant smell.

To the poster who is worried about the environment: All that scrap wood oxidizes on the forest floor anyway.

Pete Stanaitis

------------------------------------------

Tom Gardner wrote:

"Tom Gardner" wrote in news:uwBsh.17617$ snipped-for-privacy@newssvr19.news.prodigy.com:

Tom, The _correct_ way is for him to get a pallet grinder and a wood pellet furnace :) Much more efficient method of extracting energy from the wood.

"Tom Gardner" wrote in news:uwBsh.17617$ snipped-for-privacy@newssvr19.news.prodigy.com:

I hit 'send' too early.... To more directly answer the question, the flue pipe shouldn't go through the building for heat. He should have 2 chambers in the stove, one to burn the wood, one to circulate air. The air chamber surrounds the stove chamber. Forced air around the chamber extracts the heat and moves it via piping indoors where it heats the building. A separate flue stays outside. He does need dampners on both the intake air to the stove and a backdraft dampner on the flue. Google 'wood furnace' should turn up several designs.

The tank is 3/8" thick. I think it was a pressure vessel in a previous life.

With all that scrap wood, it sounds as if you ought to be building a wood fired furnace for your own use.

His tank is big enough to make it a fluidized bed furnace. They are filled with sand or something similar and use air interduced at the bottom to make the sand act like a fluid. Do a little googling on fluidized bed furnace and see if that would seem feasible.

If that does not seem like a good idea, I would suggest welding up most of the air intakes and using a blower to provide air with a secondary air inlet just before a catalytic converter. I don't think there is any other way to get that size to burn cleanly and not be glowing red hot.

Dan