Heating a small greenhouse

I've looked on the internet, but I've not seen any specific information on what I want to do. It's common to use drums of water to store water as a heat sink, but I plan on using a small alcohol jet stove to heat water in a barrel to heat a small green house. I just bought a 8x12 greenhouse kit (Palram brand) and I don' have close enough electric to use an electric heater in it.
So my plan is to place a bulkhead fitting near the bottom, convert the pipe from CPVC to coppper, then back to CPVC into another bulkhead fitting at the top. In the middle of this system, I'll angle the copper pipe at a 45 degree angle, and have the alcohol jet stove to heat the water. The heated water should rise, and cause natural circulation. I'll build a box over this section out of backer board lined with galvanized metal hold in more heat, it will be open at the bottom. That should make it heat resistant using those materials. I'm using alcohol because it will burn cleanly, and provide CO2 which should help with plant growth (so I'm told). I'm making the jet stove out of an unused gallon paint can for more capacity, hopefully it will burn for a few days before refilling. I can get a 5 gallon bucket of alcohol from Menard's for about $40.
I also want to supplement the heat with a compost bin, and reflective heat blankets (like they use for runners on cold days), so hopefully I only need to use the stove on the coldest days. My intent is to be able to grow veggies during the winter.
Anyone heard of this kind of setup?? Any thoughts? I plan on doing a Youtube video, good or bad outcome.

Sounds like a lot of project that may or may not work, so you can use $8/gal fuel. WWhy not just get a kero-sun style kerosene heater? I am not sure what an alcohol jet stove is , but if it is some sort of camping cookstove, I doubt if it will be adequate. Using it to heat water will not increase the heat output. You will have your greatest heat demand at night . Will this alcohol stove hold enough fuel for 10-12 hrs or will you have to go refill it in the middle of the night?

Kind of an interesting stove design. Had to look it up.

Too bad E85 ethanol fuel doesnt fit your needs, would be a much cheaper fuel. But I suspect the 15% gasoline would not meet your approval.

Good luck with the project!

Paul

We have 2 30ft x 150ft greenhouses that are heated by 2 225,000 btu (best can remember, could be 250,000 btu) Hired Hand LP gas heaters. They are placed 1 on each end on opposite sides of the houses. Both houses do have double layers of plasic for the top. They barely will keep the temp at 75 degrees with no sun and the outside temps in the 30s to 40s. Don't know how hot you need it for germination purposes where you live but I would seriously look at a 100,000 btu Lp or natural gas heater. I think this would be adequate. Think you'll be happier in the long run.

Uh, maybe you didn't read the part when I said it was 8x12'... I want to keep it warm enough to grow things in the winter, not burn it down in 5 minutes...

The jet stove concept didn't work, don't know if I did it wrong or if using a 1 gallon paint can was too much height for the fuel to draw up the wick. I just got two glass Tiki torch burners with 1/2 wicks. Seems to be working ok, had to turn them down just a bit as it's building up too much heat where they're heating the copper pipe. I have to protect the wood structure a bit better with so more backer board.

Started it up about 8pm tonight, no leaks so far. It was 41 degrees as I started it up, just finished filling it up. Had to use buckets to fill the drum, had a bad hose connector, so it wouldn't reach. Two hours later, it was still 41 degrees inside, but the water in the drum was getting warmer, it was probably 55 degrees or so out of the tap, so it will take a bit to warm it up. I'll have to protect the wood frame a bit better, there was a bit of char from the heat coming out of the heating chamber on one end. I'll probably use steel studs to replace that section or add more backer board. I opened it up so heat can escape without burning the wood

It was 16 degrees f this morning.

In winter, at 20 below, the heater he mentioned might be about right for your size greenhouse, if it were located here.......

Paul

100,000 BTU's is about SIX TIMES what I'd need for this greenhouse. My bathroom is bigger than this greenhouse... SMH...

I have a shed that's a bit larger and needed electric for my tractors (block heater's, shop lights battery charger etc. I decided to go with a solar panel kit from HF. I also purchased a large group size 27 deep cycle battery and a power inverter. I then wired my shed for 120 volts and installed a 5,000 lumen LED shop light which really helps a lot for my old eyes. I put my solar panels over my shed entrance at the suggested angle which makes it double as an overhang. I've run a power sander and had the lights on for what I think were extended periods without any noticeable lack of power. I don't know how much temperature you'll need, but you could also use the power for grow lights. Good luck.

Additionally, my son worked for a golf course about three years ago and said he used timers, pipes, solenoids and collected rainwater to drip irrigate his plants inside his greenhouse there.

Well, I hope you can get it worked out. I would be very concerned about fire risk from what you have described. One big factor- what part of the country do you live in ? Heat needs in my neck of the woods would be much greater than a southern area.

I'm confident that there's little risk of fire. (I'm a firefighter, so I plan for fire safety) I am going to make some modifications though. I'm going to expand the amount of copper pipe, and increase the size of the heat exchanger to transfer more heat to the water.
I'm in Central Ohio.

I wasn't real impressed with the results, but I have a couple of things I'm going to try. I'm going to increase the amount of copper pipe in the heating area by running the pipe back and forth a few times. I'm also going to try using E-85 fuel as it's mostly alcohol, but a LOT cheaper. I think If I run the burners at full strength, it will help. The water does heat up a bit on sunny days too. Not a total failure, but not an overwhelming success.

WAY out of my budget...

I built a 12x12x8 with clear plastic corrugated panels I bought at the big box store. Propane tank was nearby that fueled the house so I tapped into that and put a radiant 2 burner wall mounted unit I removed from the house for some reason...guessing 10k BTU. 20s were the coldest days and it worked but I needed deep pockets to keep the propane supplied. No insulation and vent at the top (2x4) gap where the roof rafters sat which I plugged in the winter with foam blocks, made for a hard to keep warm place and that's here in N. Texas, not N. Montana.

I know you said no electricity, but I used them too, the red radiant type and they worked ok for spot heat.

My opinion of one is to use it for garden storage and clip pictures of what you like to see out of magazines and paste them to the walls!

Nothing to do this AM so let's play with some numbers:

Propane is about 91k BTU per gallon and costs roughly $2.50 in small refillable bottles. 10k burner or maybe 15 or 20 in Northern climates, running full blast 24/7: 9 hrs per gallon, 2.5 gallons per day, $75 per month for 10k BTU burner......sounds like a wise investment................ I think I recall telling my wife that her idea, after building the thing, outfitting it and all that goes with it, was not well thought out.......after surviving the first winter. Besides that she didn't have a lot of things in there to protect.

After some trial and error, I've found a solution I think will work well. I can get an adapter so that I can use Bunsen burners off of a 20lb propane tank to heat the water. All the burners that I could get for grills or camping were too big, but a Bunsen burner like they use in labs and chemistry classes should work great. I figure two burners would be enough. It's warm enough now that I don't need any heat source, but I'll get this rigged up in early fall to try it out. Should cost less than $100, and I already have a couple of tanks.

GeoThermal

Dig hole under greenhouse location, as deep as possible without hitting water, preferably 8'+. Line hole with 6 mil plastic sheet, (air/water barrier). Build framing to hold 6 inches white insulation board against bottom and side, seal pieces tightly. Fill 2 feet soil/gravel/sand, any or all. Lay 6inch black flex pipe 2 feet apart across 2'soil and up side walls with 2' left above ground. Pack around pipes filling 2 feet more soil, then another layer of pipes, 4 layers total. Pack and fill tightly around pipes and the hole generally. Fill to ground level. Build box to terminate pipe ends at each end of greenhouse. These will sit on top of pipe and create a vacuum box. Cut 6 hole in top of box. At one end a duct fan goes in that hole, at the other end another pipe goes in hole, then up along center of ceiling and acts as intake plenum. Most systems split the pipes into two sets, so at one end of GH you'll have two boxes with duct vents, and the other end will have two boxes with pipes up to ceiling. Duct fan pull air from warmest point, ceiling, down through pipes into ground, warming it. During day when sun warms GH fans pull warm air in. At night warm air is extracted from the ground. Fans are blowing ground temp, up to 70+. DC duct fans pull very little current and push a lot of air, at least 500cfm ea., so two make it a lot, able to turnover all the air in a minute or so. Ground is naturally 52degrees at 8ft. You can warm it more during summer and start the winter with ground at nearly 80. If you grow plants that are tolerant to 32 it works. Citrus trees are perfect.

I built one. It works. With solar it's free warming. I haven't gone solar, I trenched a big wire, but that's not hard to do, and now we have 30amp available way out in a backyard field, which is nice. Greenhouse uses almost nothing. Far less than $1/day.

More info to anyone interested. Mine is just a good 1 3/4 pvc hoophouse, but they can use any type of GH structure. TMANY more details, but very easy to build. Amazing technology, needs to be developed further. No need to be trucking citrus into the Midwest and North, ever.

John S-B said:

I've looked on the internet, but I've not seen any specific information on what I want to do. It's common to use drums of water to store water as a heat sink, but I plan on using a small alcohol jet stove to heat water in a barrel to heat a small green house. I just bought a 8x12 greenhouse kit (Palram brand) and I don' have close enough electric to use an electric heater in it.
So my plan is to place a bulkhead fitting near the bottom, convert the pipe from CPVC to coppper, then back to CPVC into another bulkhead fitting at the top. In the middle of this system, I'll angle the copper pipe at a 45 degree angle, and have the alcohol jet stove to heat the water. The heated water should rise, and cause natural circulation. I'll build a box over this section out of backer board lined with galvanized metal hold in more heat, it will be open at the bottom. That should make it heat resistant using those materials. I'm using alcohol because it will burn cleanly, and provide CO2 which should help with plant growth (so I'm told). I'm making the jet stove out of an unused gallon paint can for more capacity, hopefully it will burn for a few days before refilling. I can get a 5 gallon bucket of alcohol from Menard's for about $40.
I also want to supplement the heat with a compost bin, and reflective heat blankets (like they use for runners on cold days), so hopefully I only need to use the stove on the coldest days. My intent is to be able to grow veggies during the winter.
Anyone heard of this kind of setup?? Any thoughts? I plan on doing a Youtube video, good or bad outcome.

Click to expand...

The link shows the cost per million btu of heat for various energy sources .

In rough numbers , an electric heater costs 1/3 the price of using ethanol alcohol . With the added bonous of avoiding fires, explosions . Injury or Death from CO , CO2 or burns .

The electric does not require refilling every few hours .
How high is the ceiling of the greenhouse ? Those weed plants are going to be 6ft tall by spring time .