What Is The Efficiency Hit With An Outdoor vs. Indoor Gasifier?

velvetfoot said:

Just wondering what the % might be, and if it's considered significant. Otherwise, it would seem the outdoor models could be attractive.

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That's tough to quantify, I suggest an efficient indoor gasifier in an insulated outbuilding. The advantage to outside is you can stack wood only once and you won't use up indoor space and won't create indoor mess/smoke. The disadvantage is the heatloss from the unit and the piping. I think each person has to look at it individually to fit their needs. Good luck.

Like Hydronics, I have an EKO 60 in an outbuilding--in my case an insulated "boiler room" made out of cinder blocks, etc., in my barn. It's nice to have all my wood stacked within easy reach, and all the mess and smoke stays out there. It's also nice to have it all under one roof.

That said, I've had indoor wood boiler installations as well as this one, and the standby losses with a remote unit are considerable. You burn more wood. But it's probably worth it. How much more? No idea, given I have no way to compare apples.

One thing I learned from Webmaster Craig is something along the lines of "the bigger the firebox, the higher the wood consumption." It's true; can't get around it. Dedicated outdoor boilers all have huge fireboxes. Just something to bear in mind.

I have mine in a outbuilding. The wood drys vey nice in the room. I think it might be harder to run a gasifier if your wood outside with the potential to get rained or snowed on.

It would also add to the difficulty if you want to run storage. My boiler is off most of the day. With an outdoor I would need glycol and an exchanger between the storage.

gg

Your definitly going to burn a little more wood with a remote unit. I don't Know how much more but there is definitly heat loss from the boiler and lines. For me it worth it to burn a little extre to keep the mess out of the house. I heat 2 buildings not including the boiler shed that stays very warm, so I had to have the underground lines anyhow.

Shell loses are going to be large with any unit that sits in an unconditioned space, even worse if it just sits outside exposed to the elements on all sides at all times. I think it's been said in these pages before that any boiler belongs in a conditioned space. I could'nt agree more.

If you want a hard answer to your Q go to an engineering site on the web, pick a vessel size say 100 gal for easy math, then choose an outside temp say -20F as your coldest. Given that size & temp you can calculate how many btu's/hr you will lose & adjust that for R factor of insulation. If you find a site that will let you factor in the wind & the rain you can calculate those losses too. Short & no science involved answer: any heating unit sitting outdoors is going to consume much more fuel than the same unit in a conditioned space.

Yes velvet. One can insulate the underground pipe well enough that heatloss is difficult to measure ( a fraction of a degree F ). Same goes for the conditioned space a boiler would sit in. Very hard if not impossible to insulate a unit that is designed to sit outdoors so it would have equal heatloss compared to one in a conditioned space.

I once did a heat loss calculation on a CB outdoor wood burner (foam insulated) and a Woodmaster(?) with fiberglass insulation for a customer looking at both of them. They each came out between 5 and 6,000 btu heat loss per hour through the jacket alone.CB was slightly better through the jacket but lost out with their totally exposed flue collar hanging out the back of the unit.
Think about it. In some cases you may be trying to maintain a temp difference of nearly 200* from water to air and it's being insulated with only an inch or two of foam or 6 inches of mouse eaten fiberglass.