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Wood fired garage heat

Posted: January 13, 2018, 7:15 pm
by mercuryv8
I need a bit of advice. I'm building a wood fired stove for the garage. It's going to be outside, and the heat pumped into the garage through 4" pipe. I have pictures but essentially I'm makeing a 16" stove inside of an insulated 20" pipe. 2 feet long, the stove will sit horizontal.

My question is, would it be best to come straight up at the back of the stove for the chimney or out the end and make an elbow outside of the stove.



I don't really know about how the drafting inside the stove works.

Nic

Re: Wood fired garage heat

Posted: January 13, 2018, 8:28 pm
by jamesdfo
Nic: No answers for you on the technical end, but I would check with your insurance company, because when I bought my house, it had a wood pellet stove in the basement (fully finished), and the insurance Co I had been using for YEARS wanted no part of it......so I ended up moving ALL my business somewhere else. But better to know where you stand going in, than have them refuse to pay out a claim because they were not aware you had a wood stove......

James

Re: Wood fired garage heat

Posted: January 13, 2018, 9:02 pm
by mercuryv8
I don't think they would ever approve it because the stove is home made. I figured outside is the safest place for it. Makes for more room in the shop too.

Nic

Re: Wood fired garage heat

Posted: January 13, 2018, 10:51 pm
by Gravemetal
A buddy of mine tipped me off to this concept a good 15 years ago. Europe has been doing this for decades. I cannot remember which country, I think it is Norway, made it law to have the fire shed separate from your house so that you do not burn the joint down. One hell of an idea. If the stove is isolated from the garage I would think it would not affect your insurance. Google Europe for the future lol!

Re: Wood fired garage heat

Posted: January 14, 2018, 3:05 am
by slick4x4
I would come out of the top of the stove...
You can pu in a damper in the pipe for control
I have seen them running outhe back ...
Bu sometimes that style can smoke
When you open the door......
Also the elbow is just a place for ash to build up

Re: Wood fired garage heat

Posted: January 15, 2018, 3:49 pm
by The Big M
So are you just trying to draw warm air from the 20" pipe? As in the 4" pipe will just deliver warm air and you'll have a separate chimney exhausting directly outside? Is the 16" concentric inside the 20"?

My dad built a wood stove for his ice fishing shack out of a 20 lb propane tank (mounted horizontally), but a big part of why that works so well is that it's right inside the shack so you're getting radiant heat from the firebox itself and the chimney (which is on top of the cylinder, btw). Plus it's a small space. I'm not sure how well forced air would work if it has to travel a distance to the garage.

Might want to check your local bylaws too, if you haven't already. Assuming you're surrounded by city dwellers who might complain about the smoke, that is.

Re: Wood fired garage heat

Posted: January 15, 2018, 6:41 pm
by mercuryv8
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Here is pictures of what I have so far. It's going to sit horizontal. The first picture shows a 30# propane tank inside. I was originally going to use that, but it looked too small.

I think I'm going to take the advice above and come right out the top with the chimney.

The air in and out is going to be in on the bottom front and out back top near chimney.

My yard layout will allow me to put it pretty close to the garage. With a straight run for the ducts. I made the front and back plate oversized so I can use them to hold the cladding and then I can insulate the outside.

Nic

Re: Wood fired garage heat

Posted: January 28, 2018, 8:23 pm
by tomrooster
If your planing on supplying the garage with a 4" pipe connected to the 20" you will have to also have a 4" return as you won't want to heat ice cold air from outside and you won't get a strong supply of hot air without a return line. I'm assuming you will use a small fan to supply the garage. Tom

Re: Wood fired garage heat

Posted: February 1, 2018, 12:29 am
by mercuryv8
tomrooster wrote:If your planing on supplying the garage with a 4" pipe connected to the 20" you will have to also have a 4" return as you won't want to heat ice cold air from outside and you won't get a strong supply of hot air without a return line. I'm assuming you will use a small fan to supply the garage. Tom
That was the plan, I was actually going to try it without and see what happens. Then when it didn't work I would put the 4" running from inside the garage to the stove. I figured a small inline fan would work. Although I did look at my dust collector... But might be a fire hazard.

Do you think heat exchanger fins are required to slow the air when it's in the stove? I guess they would be less nesisary if I used recirculating air.

I was even thinking I could put a thermostat on the little fan.

Nic

Re: Wood fired garage heat

Posted: February 1, 2018, 2:48 pm
by slick4x4
I would put some air deflector fins in there ... if you put them at angles ,
In a circular design , the air would get a spinning effect & grab all the heat
Evenly (they do this in the chimneys of gas water heaters ) you definitly
Need a fan ... 4" is too small for gravity flow circulation ... inlet & out
Probably need to be on opposite ends & opposite sides of your stove ...
you can get a "Fan switch" for turning your blower motor off and on..
they use them in Furnaces , when they heat up , they make contact &
power the motor.....I got mine out of an old gas furnace, any heating shop
could sell you one...
The fan switch should be placed on top & near the air outlet , that way
It will cycle less when the stove comes up to tempiture

Re: Wood fired garage heat

Posted: February 1, 2018, 9:23 pm
by mercuryv8
Now that I'm coming up the top with the chiminny I'm going to have a tough time getting fins in there. because to get the chiminny through the outside pipe I will have to slide the inner inside then raise it up. I guess welding long fins across will have to be good enough. I will try to stagger them into channels and see how that works.

Thanks for the good ideas.

Nic