Distributing wood burning stove heat

I have a 20'x30' old shed that I'm turning into a office/workshop. The office will occupy a 8'x15' corner of the workshop and be walled off and insulated from the rest of the workshop. I was given a fairly large wood burning stove by an uncle and I'm wondering how best to use it to heat both office and workshop. The office will be my home office and will house a couple of computers a desk and a couch. Right now I have no insulation and no walls put in and the stove is sitting in the corner not hooked up so I'm not fettered by any existing construction. I will be insulating the walls and the ceiling eventually. A couple of other factors. This is in central Illiois so the winters can get pretty cold. The roof is a fairly flat slant and pitches to the north only, it's just a one-way slant whatever that's called. There is a big sliding door on the east side that I'm not quite sure how I'm going to insulate yet. Several questions: 1) Is there a certain place to put the stove to get the best distribution. I can probably put it along the shared wall of the office and workshop to get a central location but I don't want to have it in the way too much. 2) Can I distribute the heat by routing the exhaust pipe through the building? Does that put off much heat itself and are the ways to help that along? 3) Are the are any precautions I need to take if I route the exhaust through the drywall walls from the workshop to the office? 4) Is it any better to send the exhaust out the wall than the roof?
I'm sure there are lots of other questions I should be asking as well so I'd really appreciate any insightes you've got.
Thanks, Nate Baxley
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Check the fire codes.. It can be done, but ther must be some cleaance between the stove and wall. Even with sheetrock on the wall, it must have some protection. There are heatshields available or you can make one.

Years ago, it was done like that all the time. Visit some historical homes/shops and you will see pipes going horizontal for 10 or 12 feet across a room.

Probably but I don't know the latest codes. There are shields available.

In any case it must clear the roof by a certain amount. It may be easier/cheaper todo it one way over the other but that will depend on your construction and particualr layout. The pipe must extend a few feet to ensure a good draw.

You can install a vent between rooms to help heat flow. A small fan can make a huge difference. It is also possible to have too large of a stove. What happens is that you cannot run it hot enough and you get a creosote buildup in the pipes and chimney. Be sure to have ways to access the pipes to clean them. Perhaps when you buy the pipe at a good stove shop the guys can give you some installation tips.
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A 20X30 shed should be no problem for wood burner. Some of your questions depend on local building code. Taking the pipe through the wall should require a double wall pipe. Remember this is radiant heat. I had a medium size wood burner in a unfinished basement 28X48 and could actually run you out with the heat. This was in the mountains of WV, some winters hit -25. I wouldn't be running exhaust pipe all over just for the heat it produces. You want a good 'draw' on the stove to get it operating at its best. Insulate the outer walls. You can run the exhaust out the roof, or out the wall AND then up. All stove pipe on the outside is a waste of heat. As others said, you need it above the roof line to get a good draw. I put a damper on the pipe just above the stove. Between this and the air intakes on the doors of the stove I could control the heat very well. If you must build interior walls consider vents in the wall to let the heat circulate. You could even put small fans in the vents. These wood burners can really put out the heat. Don't put a good size stove in a small room. You will have a room you can't stand to be in. As I stated this is radiant heat so keeping the stove as far from walls as possible give you the benefit of heat from all sides of the stove. If it's near the wall, remember to be VERY aware of combustible material in the wall. As you probably know the type of wood you burn will make a difference. Red oak and white oak work great if good an seasoned. Pine burns fast. I don't know if you have locust trees where your are. If so, be ware, locust can burn with near the heat (btu) as coal. You can ruin a stove with locust. Find a store for wood burners, they should answer any questions on local codes. Good luck.

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Wood is work. More insulation means less work...

NREL says Peoria is 27.0 on an average December day, with a 34.6 F average daily max... 830 Btu/ft^2 of sun falls on a south wall.

Maybe you have a 10'x30' south wall. With a layer of polycarbonate glazing (about $1.50/ft^2 in 4' wide rolls, with a 10 year guarantee), you might collect 0.9x830 = 747 Btu/ft^2 and lose 6h(80-31)1ft^2/R1 = 295, for a net gain of 452, or 135.5K Btu for the wall. You could keep the shed 65 F for 8 hours if 135.5K = 8h(65-31)G, ie if the shed's thermal conductance G = 498 Btu/h-F or less. G = 900 ft^2/R makes R = 1.8. Not much :-)

That might come from Grainger's $80.55 4C941 450 F 136 cfm blower with their $16.38 4WZ05 speed control pushing cooled flue gas up a chimney.

A forced draft might go out a window...

You might control the heat with a thermostat (eg Grainger's $13.25 2E158) that turns off the draft blower when the room's warm enough. Another in series might turn on the blower when the stove is hot.
So long as you don't need a natural draft, why not suck more heat out of the fluepipe? The draft blower might be near the outdoor chimney connection (if any) and its long 6" fluepipe could draw air from the stove outlet. Meanwhile, the middle part of the fluepipe could be inside a 10" pipe with a T and a 10" to 6" reducer at one end to make an air-air heat exchanger. The T could be mounted horizontally near the chimney, with Grainger's $70.85 4C847 550 cfm 10" fan at the far end (also controlled by the room temp thermostat) pushing room air into the T, through the space between the inner and outer pipes. The room air would emerge warmer from the end near the stove.
Meanwhilst, the flue pipe would slope towards the chimney, and flue gas would enter the blower from the 6" vertical pipe below the T, via an elbow with a pinhole to let condensation drip into a bucket and exit the blower into the outdoor chimney connection at X. A condensing chimney might produce at least 15% more useful heat than one without, with the same wood consumption.
The setup might look like this, in a fixed font like Courier:
10" pipe ______________________________ ___________________________ f 6" pipe / -------------------------- \ <== a || ----------------------\||/----n -------- || 10" elbow --> ||_________| X | || \ --> blower | || \---------|________| || |<-- L -->| --------- draft | | inlet--> | stove | --------- | drip | | | |bucket| -----------------------------------------------------------------
If 20 cfm of 600 F flue gas enters the L' fluepipe and the fan pushes 400 cfm of 70 F room air into the 10" pipe, and we want the exiting flue gas temp to be 212 F max, E = (600-212)/(600-70) = 0.73. Z = Cmin/Cmax = 20/400 = 0.05 and E = (1-e^-(1-Z)NTU))/(1-Ze^-(1-Z)NTU)), so NTU = 1.347 = AU/Cmin, = 3.14L/20 in this counterflow heat exchanger, and L = 8.57 feet, or less, with condensation in the inner pipe.
L = 10' would be convenient.
Nick
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