Masonry heaters...

[Paschale]

Thanks for the reply.

Where was this house located?

I live 3 hours North of Fargo.

If my understanding is correct, these masonry stoves started in Finland, or at least are very widely used there.  I think Fargo can't be too much colder than Finland.   ;D

[Dave Shepard]

Don P, I think the ratio of water to steam is one gallon=1700 cubic feet of steam. That is why steam engines are so leathal when they blow. They have 200 gallons of water heated above 212, which under pressure has a higher boiling point, and when the boiler ruptures and the boiling point lowers,  !


Dave

[Karl_N.]

There's an article on the Backwoods Home Magazine called Better Wood Heat that I found interesting. He writes about barrel stoves with lots of mass surrounding it. He also writes about a fresh air inlet that makes tons of sense. A wood stove exchanges the air in the room three times in an hour. That's a lot of cold air being drawn into the house.

[Joel Eisner]

We installed a woodstock soap stone stove in our timberframe this past fall.  It heats about a 900 sf area.  Other than the 300 sf or so of radiant in the lower level it is our only heat source we are currently using (we also have radiant upstairs that we are not using).  The house stays real warm ~75 deg with about 9 +/- pieces of 6in dia 26 in long hunks of wood a day.  I burn oak, poplar and syp and it  burns very clean and has decent thermal mass.  The stove plus all the chimney and fittings ran $3500 and was well worth it.

[Thehardway]

I've already bought a rumford kit and a bread oven kit from Superior Clay but haven't started on either.  The Rumford kit includes the throat, the damper, correct flue liners, smoke chamber, and firebrick.  I sure hope it works!  Supposedly, if you follow their directions and the throat fits on top of the firebox that you've built, then it will work. 

Also, thinking about building my own outdoor (or indoor) wood furnace to produce hot water for my radiant heat floor.  I too cannot understand why they should cost so much.  I'm currently heating the unfinished house with a barrel stove that I picked up at the scrap yard for scrap price.  (actually, we're just burning an armload of wood per day on the days we work to take the edge off) and it keeps the house in the 40's while it has been between 0 and 20 degrees outside for nearly two weeks.  I am amazed at the simplicity of the barrel stove, and searching for the water jacketed analog of it.  (couldn't you just put a coil of pipe around a barrel stove if you weren't sure of your ability to produce watertight welds?  or buy a watertight tank and weld a firebox to it?) 

Also wondering if one couldn't put waterpipes in the chimney of my rumford setup and feed that to the radiant heat floors?  (But I guess cold flue temps = more creosote build up)

-Thomas

Thomas,

I have plans for an outdoor woodstove with a welded plate steel water jacket.  A fellow who built it says it is very efficient and will easily burn 24hrs on a armload of wood.  If you are interested in the plans drop me an email.

As for wrapping a coil of pipe around a barrel stove I wouldn't reccommend it.  Wood burns at temps much higher than the boiling point.  The water in your coil would quickly turn to steam, generating pressure.  Unless you have a steam pressure let off your pipe will explode causing possible injury and making a big mess.   On the other hand if you have an endless supply of water you can use the steam to generate electricity as well as heat your home.

To do the barrel stove right you need a large insulated storage tank filled with water, a heat exchanger, circulating pump and a coil filled with a propylene glycol mix and an expansion tank/let off valve with overflow (basically a car radiator system).  The hot water in the tank can then be used as needed in your radiant floors and/or a water/air heat exchanger (fancoil) for a forced warm air system. The circuating pumps are thermostatically controlled so that the water is never allowed to stay in one place long enough to generate steam.

Most of the ones I've seen were not built well. I'm no mason but I believe Count Rumford laid out a set of ratios for not only the firebox that you see but the throat and smoke chamber area as well. I've never worked around one of the Superior Clay models but I understand they are dimensioned correctly.
If you look in some of Stickley's drawings you'll often see a metal hood over the fireplace. We mounted something similar on one that spilled alot of smoke.

The Count was an interesting character if you've never studied him.

There is much more to Stickley's "Craftsman Fireplace Furnace" than just the metal smoke hood.  I have a diagram of the entire system in the back of his book "More Craftsman Homes" and it shows a type of smoke maze in the back of the fireplace whereby heat was extracted from the smoke and exhaust gases of the burning wood or coal and sent up into a cavity where it could be sent throughout the house in a series of pipe ducts.  The smoke continued up the chimney through a side outlet in the maze configuration. There was also a return air system.

The Count Rumsford designed fireplace is based on a venturi principle.  The shallow design allowed the heat from the fire to rise straight into the room while the specially designed throat sucked out the smoke without letting the heat up the chimney.   

One thing for all of us to keep in mind with fireplaces in today's modern airtight homes is that all firplaces require make up air for the chimney draft.  if your house is too tight the chimney won't draw and the fireplace will just smoke and can literally kill you by oxygen depletion.  The only solution is to open a window or door unless you design an air intake to draw in outside air in the fireplace.

This is a great topic.  It could really use it's own section of the forum.  I would love to see some pics of fireplaces, woodstoves, masonry work and homebrew heating and cooling systems that members of the forum have installed.  Just about very logger or sawyer has some kind of love or hate relationship to firewood or woodstoves.

Other than the 300 sf or so of radiant in the lower level it is our only heat source we are currently using (we also have radiant upstairs that we are not using).

Joel,

Whats the scoop on not using your upstairs radiant heat?  Are the floors to thick?  I have heard of some people having trouble with under the wood subfloor radiant designs. they say they respond too slowly to work good and the water temps have to be pretty high to counteract the woods insulative properties

I guess the downstairs is working good? What is the heat source for the downstairs radiant?  Any words of wisdom on radiant systems other than "avoid PEX termites?" :D

[Joel Eisner]

Joel,

Whats the scoop on not using your upstairs radiant heat?  Are the floors to thick?  I have heard of some people having trouble with under the wood subfloor radiant designs. they say they respond too slowly to work good and the water temps have to be pretty high to counteract the woods insulative properties

I guess the downstairs is working good? What is the heat source for the downstairs radiant?  Any words of wisdom on radiant systems other than "avoid PEX termites?"

The radiant heat under the wood floors works great.  The only problem is that the soap stone stove is too much fun and takes care of the heating with a few small loads of wood a day.  On a warmer day (outside getting up to ~55) we burn a small fire in the morning and the thing radiates all day and into the night.  If it is cooler we will load it again in the late afternoon.

The unexpected thing that we are finding is that the lower level (~300 SF) of concrete floor that we do heat with radiant acts as a thermal mass and helps keep the house in the 60's without the stove or upstairs radiant running.  Also, all the timbers etc seem to help buffer the temps.

Finally, the house is positioned to pick up as much passive solar as possible.

Joel

[Thehardway]

Awesome! hopefully you will have similar results with the themal mass for cooling in the summer months without getting condensation. 

[Don P]

We,ve run into the same thing with the radiant at work. We've been running just the basement zone and not the main floor loops and the house has been doing fine. That is nice heat.
Bob, I didn't know the craftsman hoods were a part of a mass storage fireplace. That's worth some more googling  8)

[Raphael]

Very cool... or warm.  ;)

  We're putting radiant heat below the first floor and leaving the second floor generally unheated, except a short loop in the floor of the bathroom.  Good to know I'm not suffering from a complete case of HUB.

[Thehardway]

Don,

It really has no "Mass Storage" capacity, it is more akin to a Heatilator fireplace with advanced ductwork.  I'll try and scan the diagram.

[Joel Eisner]

The Stickley fireplaces are a neat design.  I have seen them in person (at Stickley's home)and while I would not want to heat a whole house with one they sure must have done a better job than a regular fireplace in the old days.