Picking a wood stove for a 30x36' hoop house.

[DancingWolf]

Mhmm, hot air rises. I get nice heat coming out of the flue before the 'Tee' when the stove isn't running, it has tactile suction when the stove is disconnected as well but with the stack in place. I suppose having a few holes makes the damper function closer to its intent, since air can be pulled from behind the blockage.

 

[begreen]

Once a decent fire is burning you should be able to damper down a bit. More chimney will help. It will take some experimentation, but I assume the goal is to burn less wood and have an overnight fire.

 

[MAD MARK]

I appreciate that you keep coming back and respond, although lots of negative feedback. (Me included) Keep up the updates.

Secondly, I second Highbeam in the fact that no one should replicate this setup. Experimental or not.

Thirdly, I grew up on a double barrel stove setup in my dads garage that at the age of 13 he felt safe enough to let me use it when I wanted to. Looking back, scary.

Fourthly, no one should replicate this setup ever.

 

[DancingWolf]

I appreciate that you keep coming back and respond, although lots of negative feedback. (Me included) Keep up the updates.

Secondly, I second Highbeam in the fact that no one should replicate this setup. Experimental or not.

Thirdly, I grew up on a double barrel stove setup in my dads garage that at the age of 13 he felt safe enough to let me use it when I wanted to. Looking back, scary.

Fourthly, no one should replicate this setup ever.

I checked up on the fire (2:30AM) after a restock at around 9PM, hot coals and easily restarted. Greenhouse was quite warm if a bit smokey, still got some sealing to do on the stove. CO meter wasn't going off but the stove pulls in fresh air from various areas. The other half of the greenhouse was dripping condensation due to the temp difference, it should clear up. (picture of hot coals before putting more wood in.) Seems it will do fine for six hours if its loaded up with wood. I need to fill up on gas and find me some more dead trees.

A benefit of the location on the hill side is that since its a decent hill of 30-40Ft, its a decent thermocline effect. I'm aware the term is used for water but its used a bit in an old mountain course I went though a few years back. Since its not at the very top of the hill, it benefits from the cold air sinking away and warmer air flowing up the hill. No frost up there while there's ice at the bottom, ideal place to make a camp.

I've only seen one demonstration setup on youtube for indoor use but it was on a massive hearth, everything protected from it, and the double barrel had the extra four miles put into it. For the price of all the extras it would make more sense to just get the biggest EPA heater you can find and put in a normal size everything else. Not an indoor heater. I'm surprised there aren't more "out door" heaters that skip ratings and all the EPA mandates, seems like a good back door route.

It appears that I never cemented in the top cast adapter piece, probably because I had intended to take it back off and grind out the rest of the barrel edges so the damper would stop getting stuck but I ended up putting that in the stove pipe. It leaks some smoke depending on how much the damper is closed. The last four inches of my door gasket didn't stick so I need to touch up that when its warmer in a few days.

As for negativity, it just the usual elitism found on some forums. The government confiscated anything I lack for tuning people out. The thread has pretty much run its course though, and I appreciate all the feedback and tips. I might move all my plants into this greenhouse since it can be kept warm. Interior was 65? 70? going by feel, outside is "37" according to a sensor a few miles fromhere, but ahem, there is frost and solid ice outside so I know thats a lie. Temps are also probably measured a few feet off the ground. I'm sure the heater output could be calculated by the temperature difference and area / cubic space but I'm too lazy for that. It heats, and hopfully I won't have to dust the pipes out too often.

Going back to bed now. <3

 

[Seasoned Oak]

If you have enough free wood you may also want to look into a stove that burns all night if and when the budget allows. I just about gave up early on with wood burning starting out witha smoke dragon that would only go a few hours on a load of wood. After i bought a real stove i was hooked,mostly on its ability to go many hours on 1 load putting out steady heat.

 

[SpaceBus]

This is a good proof of concept.

First thing is to figure out why you have smoke coming into the greenhouse, it should not. Smoke only leaks out of a stove if draft is poor, as begreen mentioned.

Unfortunately you are attempting to heat with wood in the worst possible scenario. If you can get the plants to survive this winter then next winter would be even easier with an EPA stove like an NC30.

 

[DancingWolf]

This is a good proof of concept.

First thing is to figure out why you have smoke coming into the greenhouse, it should not. Smoke only leaks out of a stove if draft is poor, as begreen mentioned.

Unfortunately you are attempting to heat with wood in the worst possible scenario. If you can get the plants to survive this winter then next winter would be even easier with an EPA stove like an NC30.

They better survive the winter, or my business goes under, there really isn't any reason why they shouldn't. I used to drag them inside to my bedroom for the first few years, built a small greenhouse and they survived in there with electric + propane heating. The smoke comes in because the damper is closed too much and the fire is trying to force smoke up the flue, positive pressure vs negative, its not sealed on the top of the barrel where the flue connects. I lathered up a good amount of gasket cement around it and patched the door, so it should seal better.

The stove seems to burn well for 5-7 hours which I can live with, there were a few hot coals in the ashes this morning at 10, 10:30 AM, which was 8 hours since I last threw wood on it and the GH was still warm but the sun was up so its debatable about how much was carry over from the stove. I don't see myself justifying another $500-800 on an NC-30 when it won't provide added benefit or make me money. Not to mention I'll need perfectly seasoned wood, a 14' tall stack (more $$$) and I would need to put a telephone pole in to support it. I don't mind a bit of smoke when the door is open, as long as its not filling the GH, which is isn't. Getting more wood is trivial, I have another dead cedar tree next to the greenhouse I need to clear out today or tomorrow.

This one was a lot of hidden expenses, had to get a stronger ladder and I regret not buying the 12' varient, would have made life much easier (and safer). Add in brackets, sweeping brush kit, fan to blow the heat around, etc, adds up to a lot more than expected.

 

[Seasoned Oak]

One of the benefits of that barrel stove is ,its not picky about the wood. Looks like it is performing as expected.

 

[SpaceBus]

If smoke comes out into your hoop house that means the outside pressure is higher and draft is reversing. It might be a technical difference, but it is worth noting. Basically your short chimney is causing a draft reversal and that's why smoke comes in. Most stove flue systems are not air tight, mine included. I only get smoke indoors when cold starting on a windy day, and only sometimes.

 

[DancingWolf]

If smoke comes out into your hoop house that means the outside pressure is higher and draft is reversing. It might be a technical difference, but it is worth noting. Basically your short chimney is causing a draft reversal and that's why smoke comes in. Most stove flue systems are not air tight, mine included. I only get smoke indoors when cold starting on a windy day, and only sometimes.

Only when blocking off the flue with the damper closed or keeping the door fully open. A cracked door or closed, there is no smoke coming in. I shouldn't need to run it for a week or more now, about hit back up into the 70s and 80s, lows of 40s and 50s, so the greenhouse will be >90*F during the day and >50 at night.

 

[SpaceBus]

Only when blocking off the flue with the damper closed or keeping the door fully open. A cracked door or closed, there is no smoke coming in. I shouldn't need to run it for a week or more now, about hit back up into the 70s and 80s, lows of 40s and 50s, so the greenhouse will be >90*F during the day and >50 at night.

It's not the stove, or damper, that is causing the issue, it's the ultra short chimney. No amount of sealant will help you otherwise, since it's not an issue of being air tight.

 

[DancingWolf]

It's not the stove, or damper, that is causing the issue, it's the ultra short chimney. No amount of sealant will help you otherwise, since it's not an issue of being air tight.

Its not an issue. I only get a little bit of smoke coming out of the door if its wide open, the flue isn't pulling that volume of air through so a little bit gets back out. Once the door is closed off again and its relying on the 2" opening, there is no smoke because the flue can handle the volume of air, though 2" is a little small. If I close off the damper completely or too much, there is a bit of smoke a bit just before it. I leave it open just enough so there is no smoke coming out but I haven't got enough stats yet on just leaving it open.

It does work well enough that I'm moving all of my plants, except the infested / diseased ones, up into the larger greenhouse. My small GH will be reserved to seed growing, and quarantine. So far, the stove runs fine, just need to cut a bunch more wood to feed the beast.

 

[begreen]

I don't see myself justifying another $500-800 on an NC-30 when it won't provide added benefit or make me money.

That is smoking like an old wood-fired locomotive which means a lot of unburnt fuel (wood gas). The NC30 would use way less fuel, keep the stove pipe clean as long as the wood is dry and would burn safer.

 

[Seasoned Oak]

That is smoking like an old wood-fired locomotive which means a lot of unburnt fuel (wood gas). The NC30 would use way less fuel, keep the stove pipe clean as long as the wood is dry and would burn safer.

Keeping in mind he only needs a stove a few nights a yr , $800 for a more efficient stove may not be cost effective here.

 

[bholler]

Keeping in mind he only needs a stove a few nights a yr , $800 for a more efficient stove may not be cost effective here.

That is assuming neither barrel fails leading to loss of his green house and crops. Or the buildup in that long horizontal run catches fire leading to loss of his green house and crops. To me there are just way to many weak points in that setup. It is asking for a failure

 

[Seasoned Oak]

That is assuming neither barrel fails

Mine lasted a minimum of 3 to 5 yrs when i used them in a similar situation. He did say he may be going with propane in the near future so,hence no big investments in wood stoves.

 

[bholler]

Mine lasted a minimum of 3 to 5 yrs when i used them in a similar situation. He did say he may be going with propane in the near future so,hence no big investments in wood stoves.

Yes some last that long. Some longer and others fail very quickly using something never meant to contain fire and made out of very thin metal as a stove is just a really bad idea if you ask me. Especially when his business rides on the success of this greenhouse

 

[begreen]

Hopefully, it will make it through the winter without incident. For sure, clean the stove pipe regularly. There are lots of other threats to plastic greenhouses besides fire that can be an issue. Strong winds, hail, heavy wet snow are all problems to contend with. Some local commercial greenhouses collapsed under heavy wet snow here last February.

FWIW, business expenses are tax-deductible. That will take some of the sting out, assuming taxes are reported.

 

[DancingWolf]

I figured the thread was mothballed but it popped up on my mind and decided to check anyway.

Yes, I may have a permanent 500, or 1,000 gallon tank and commercial heater professionally installed in the coming years. It would be safer and more conveinent when I have multiple greenhouses but with the tank alone being $3,000, its out of reach for the foreseeable future. Two years at least. I also need to clear land and improve the road for a truck to even reach the location.

The stove should last a while, I packed the bottom barrel with sand, still need to add brick to it, if I can find it. Its just not really an item in the south. I might just make some out of pearlite and concrete. The barrels are also essentially new.

On the subject of fires, I'm reading that people clean their flues every 1-5 tons of wood, once a season, or once a year. One person swept once a week when they had an older model. I doubt I even have one ton of wood stored up in the greenhouse, this IS central Texas, what I do have should last most or all of the winter because I plan on only burning when the temps drop below 36*F for extended periods, such as the coming cold front on Tuesday. My original plan was to keep the GH warm all winter so everything would keep growing rather than go dormant, but it seems that just keeping it above freezing is the better option. I estimate there might be around 20-30 nights in the year were I would need heat to keep the plants alive.

I was going to scrub it out every once a season, Nov 15 - March 15 (really Dec 1 - Feb 29 ), but every ten burns or once a week doesn't seem like a bad idea if the horizontal portion really builds up as fast as Bholler implies. Its trivial to pop the pipe off the top of the stove and run a brush through it. The soot would all go to the tee and fall into a bucket, likewise, shove the brush up through the bottom of the tee to get at the stack. Any suggestions on frequency of cleaning? Weekly, monthly, or per # of use?

 

[EatenByLimestone]

Itll be different for everybody. Try it after 7 fires to see how much accumulates.then after 14 fires. That sounds like most of your burning season, you may be able to stretch it out further.

 

[Ashful]

Itll be different for everybody. Try it after 7 fires to see how much accumulates.then after 14 fires. That sounds like most of your burning season, you may be able to stretch it out further.

Yeah, you’re just going to have to learn how this setup, your habits, and your wood quality dictate the cleaning. Start frequently, until you figure that out, and you’ll eventually settle into a workable pattern.

 

[DancingWolf]

Surprise! I'm back! (Yeah, I know necro necro)

Wanted to let all the nay sayers know I didn't burn down my greenhouse; didn't even melted plastic. Not to mention, it's probably useful to someone out there to know how it went if they are heating a greenhouse this year or in the future. I wouldn't be surprised if this thread comes up in search engine results.

The double barrel stove worked great and now I know why they are highly recommended for greenhouses. Not sure how many BTUs it puts out but its probably in excess of 200K when it's freshly loaded. Can't stand within 2.5-3' of it. I'm finishing up moving everything back inside to beat the fall rains and to get more sunlight. Still need to dust out the flue and gather wood, will probably do that after it drops into the 80s in a few days.

One thing I did upgrade was adding a 90 degree elbow at the air intake; it's a nice bend and keeps embers from popping out. Sorry, bad picture. I would have hot coals for around eight hours. I think the longest I had something glowing inside the stove was 14-16 hours, but it depends on how much wood, type, air intake/burn rate, etc. I usually toped it off before bed. A few hot coals isn't much but any heat is good heat in a greenhouse during winter.

(broken link removed to https://cdn.discordapp.com/attachments/702698541163872287/751248107244748840/Stove_1.jpg)
(broken link removed to https://cdn.discordapp.com/attachments/702698541163872287/751250951398096987/Stove_2.jpg)

It won't be fired back up until around November 15 - 30th when the first frost comes for my part of Texas. Yes yes, I know the hearth is a mess right now, it will be clean and clear before using the heater. One of the biggest things I would have done differently is use a metal wall behind the stove, it would have been much easier and safer. I need to build a second greenhouse next year because I'm out of room, so that one will likely have a metal wall, if I even need a heater in it. I may just use a tank top heater (propane) for that one.

Many thanks to everyone that helped me out with this. I'm on my way out of poverty now.

 

[SpaceBus]

I'm glad it worked out for you. That greenhouse looks lovely.