A "new" climate control idea

Maybe not new but I haven't heard of it.  I'm currently kicking around the idea of using 55 gal plastic food grade barrels to help control the climate in a greenhouse.  My thinking is to dig a hole 10 ft deep, and place a stack of 55 gal drums one atop the other from the bottom of the 10 ft hole up to a few feet above ground level.  The drums are roughly 3 ft tall, so I'm thinking 5 drums.  On cold days, the earth-warmed water should go to the top of the barrels, bringing the heat up with it, while the air-cooled water sinks down to be warmed by the earth.

I have a couple of issues I haven't fully worked out yet.  I'm not sure if I should use some sort of tubing to allow water to move between the barrels.  If so, I don't know how big they would have to be to allow good water circulation.  Another way to go would be to cut the ends out of the barrels (except of course the very top and bottom).  If I did it that way, I don't know how to seal the barrels together.

Any thoughts on how to seal the barrels, size tubing needed, or simply that I'm crazy and this won't work at all?  All inputs are welcome.

I'm going to keep at this until Mike and I figure out the ultimate WI greenhouse.

Travis posted in another thread about how he sinks culverts on end in the ground under his stock tanks and the warm air from the ground rising up through the culverts keeps the tanks from freezing in his extremely cold Maine winters!  I can't remember how long he said the culverts are, but that might be something to look into, putting culverts under barrels of water or possibly culverts under containers of earth.  Culverts are less likely to get crushed by the weight of the earth than barrels, also.

Thanks Tyler.  My thinking was that as long as the barrels were full and the earth was around them, they would be able to stand up to the pressure.  The culvert idea may work better though, by alleviating the need to connect the barrels.

My idea to make a passive system is to use black plastic sewer pipe to hold the glazing on the front of the greenhouse and it would make a loop to the back of the greenhouse thermal storage then under the floor and back to the upright supports. The heating and cooling of the sun exposed pipe then drives the circulation.
An air handling would require more pipe but would avoid concerns about leaking freezing and expansion.
The air handling system would start with an open pipe at the top of the north wall to intake the hot air accumulating in the greenhouse, go down the thermal storage wall under the floor and connect to the bottom of the upright glazing support then across the top down the back wall and under the floor again to exit below the glazing. The heating and cooling of the upright delivers cooled air to the floor of the greenhouse when sunny and warmed air when it is radiating heat to the top of the greenhouse while drawing cold air from the floor..

Todd, the principle you want to utilize is called thermosyphoning and you can read about it here: https://en.wikipedia.org/wiki/Thermosiphon

I think that there are a few problems with your design idea.
1, The restricted flow between the barrels, through the piping system will almost certainly arrest the movement of the water.
2, since the opening of the barrels are on the top, and that is where the warmer rising water collects and at the same time the colder water sinks. they immediately mix with each other and create a cooler water. This will repeat itself four more times and in my estimation by the third one the temperature will be approximately the same in the fourth and the fifth barrel, therefore there will be no thermosyphoning.
3, If you cut out the bottom and top of the barrels the mixing described in 2, will occur with an even greater volume and quicker and the heat loss closer to the surface will be faster than the heat gain on the bottom and practically there will be no heat reaching the top.
4, Sealing the cut off barrels agains the tremendous pressure that 250 gallons of water can create will be very difficult and probably expensive

To create an reliable thermosyphon flow you would have to build something like the contraption in sketch I attached.

Both branches would have to be insulated to avoid heat loss and heat gain in the pipes, as that can arrest the circulation.    
Even though this setup is technically feasible I am still not convinced that it can deliver the results you are hoping for, for the following reasons:
This setup will work better, the greater the temperature difference between the soil temperature and the greenhouse temperature. The soil mean temperature in Wisconsin is between 42F-47F at a depth of 30' at 10' you can add about 3F in the summer and subtract 3F in the winter. ( source: http://www.builditsolar.com/Projects/Cooling/EarthTemperatures.htm )

Considering that your greenhouse should not cool below 35 degrees if you don't want your plants to freeze,  the temperature difference between the gain and the loss side of the system is between 4-8 F (in the winter). I highly doubt that this difference is enough to create an efficient heat exchange that would keep your green house above 35 F. If the temperature drops further it will accelerate the flow, but because of the thermal inertia, there will be a delay in heating it back up , which can cause the plants to freeze before they thaw.

A water pump added to the system can accelerate the the heat transfer between the two barrels, but depending on the size of the green house you may need a lot of barrels to keep it warm. The number of barrels would have to be calculated so that the heat transfer between the surface of the barrels and the interior air in the greenhouse would be greater than the heat loss between interior air and the walls and roof of the greenhouse.

Heating (and cooling ) your greenhouse with heat extracted from (or disposed of to) the ground is possible but I think there is a more efficient and reliable way to it, which I will describe and illustrate with pics in a later post.  

A very cheap and very efficient system, for heating, would be to bury a coil of black tubing in a compost heap. Then, with a small pump, run more black tubing in the soil and maybee also on the walls (of the grenhouse), and circulating back to the compost heap. No water loss, everything (almost...) above ground = easy maintenance...
Just be careful, with to much heat ( it can easily get over 70 C, aka 160 F ).

Anyone has experience in cooling ? I live in SE Asia, and we always have problem, with cooling ( 0 problems with heating ;o)
Cheers, Chris

Interesting idea Todd!  I think connecting the barrels end to end would be a massive challenge unless they're steel and you're a very good welder.  Piping them together would likely restrict the flow too much.  If you could seal the ends of a culvert type tube I'd think that would be easier.

As part of the thought exercise, aren't the only barrels you care about the one at the top and the one at the bottom?  Maybe if you just had those two you'd avoid the obstructiveness to flow that the middle three would provide.  I'm imagining something like Erik's drawing.  Then you have to consider how much heat will bleed off of a 43 degree tank and into a 38 degree greenhouse.  Not much of a delta T there as Erik says.  

Hans' idea is interesting as well.  I'd worry about the water filled structural pipes radiating heat all night to the cold sky (reversing the heating cycle into a cooling cycle).  Maybe a check valve to only allow the water to rise would fix that problem.

Charli (in this post) says he's using an IBC tank underground connected to a radiator to act as a heat battery and distribution system.  Maybe an adaptation of that would work for you?  Big tank down deep connected to a radiator or heat exchanger in the greenhouse with a fan blowing over it.  Then the heat exchange should be better from your slightly warm source to the air of the greenhouse.

Not sure if you noticed my post a week ago about my soil temps but I dug a deep hole to measure.  It was even warmer than the BuildItSolar numbers, which surprised me.  My surface temp was 36F, 4' down it was 41F and 7.5' down it was 45F.  My sand point well water (assuming it's 15-20' deep) is 49 degrees F.

ps. Sorry I haven't posted my greenhouse design yet, I've been distracted by working on a kitchen remodel...

Some things to consider:
Soil temperature in temperate zones is about 12oC at 1.5m depth where the daily/seasonal temperature fluctuation is not noticeable anymore.
Water of 4oC is the heaviest and sinks,  This creates thermoclines in lakes
Energy storage and recovery in the aquifer has been researched for greenhouses.  Systems include pumps, wells, and heat exchangers to harvest heat or dump heat.  One of the limiting factors is the water movement in the aquifer.  One might lose one's heat sink.  Geothermal systems with coils in the soil are widely used for home heating. Feasibility greatly depends on the price for energy in your area (the alternative, and electricity for pumps).

Go with your idea, just don't go too expensive and remember failure teaches you things. You may eventually make a serviceable system. That said, my 2 cents...

Water is realllllly heavy. I am not sure your barrels can hold the weight. Even if you welded steal barrels you are talking about continually thermal cycling them which will continually stress your materials.

I have seen something like this though. I cannot remember the company but they were selling massive plexiglass tubes for you to put in your living room. I believe they were meant to be thermal/solar banks and not planned to go into the ground at all.

As far as connecting the barrels I tried something similar with an air bridge between 3 barrels, on differing burried heights, which was heated by a hot water heater and I ended up turning it off because I was going through a 40lb tank of propane a week. My poor MI bananas died.

Once I saw something called uniseal (http://amzn.to/2jVXQCM) it became easy to implement high flow between tanks. I would advise as big as possible when it comes to moving water. I went with a 4".

I would still start with the basic passive design and anything from underneath would be a bonus.  Further, I sure drums will rust out fairly quick.  You might consider old water heater tanks. Even if they drip a bit you can top them up.

passive system the heat source are black 55 gallons barrels filled with water.The rule of thumb is 2.5 gallons/ft2 of glazing for season extension or 5 gallons/ft2 for all season.

For each degree of drop in water temperature at night then 9130 BTUs are released.

In order to make the thermosiphon work (better) I would be inclined to do the following: Through one side of my stack of four barrels, run a continuous straight four inch dia pipe from the top of the bottom barrel to near the top of the top barrel.  Join all the barrels on the side away from the continuous pipe with short stubs of four inch pipe.  So your cold falls from barrel to barrel and drops to the bottom, while your warm water moves straight up to the top barrel from the bottom one.

You could also look at making use of the excess heat from an anaerobic digester (composting with no oxygen).  There is a large scale anaerobic digester in Perth Western Australia that uses the excess heat in greenhouses set up nearby to produce out of season fruit and veg eg blueberries.

Tyler Ludens wrote:Travis posted in another thread about how he sinks culverts on end in the ground under his stock tanks and the warm air from the ground rising up through the culverts keeps the tanks from freezing in his extremely cold Maine winters!

Could you direct me to that posting, please, Tyler?

Chris Kridakorn-Odbratt wrote: A very cheap and very efficient system, for heating, would be to bury a coil of black tubing in a compost heap. Then, with a small pump, run more black tubing in the soil and maybee also on the walls (of the grenhouse), and circulating back to the compost heap. No water loss, everything (almost...) above ground = easy maintenance...
Just be careful, with to much heat ( it can easily get over 70 C, aka 160 F ).

Anyone has experience in cooling ? I live in SE Asia, and we always have problem, with cooling ( 0 problems with heating ;o)
Cheers, Chris

Chris Your request has stirred my old grey matter into a riot of ingenuity..........  I suspect you could do do what you have suggested in reverse , kind of thing  , so one end comes up in the growing area .  I don't know how efficient it would be .

During my potholing days half a century ago ..I learnt straight off that at the magic 10 oC,  pot hole explorers run the risk of hypothermia if they are totally  inactive underground due to injuries for five hour or more hours unless correctly dressed .  In Great Britain  at  3 to 5 mtrs below the surface of the ground is 10 oC all year round.

So if you have enough time & money , space & a tractor with a backhoe on it ,  rip out a long 3- 4  mtr deep 1 mtr wide trench 20 or more metres long  .
Line it with industrial heavy grade  waterproof membrane /polythene sheet ,  place loads of 4 to 8 inch diametrer  ( smaller is not so good , bigger is also not the best ) rounded river rocks in the trench to about a depth of 1 mtr , fold the sheet back over the rocks so in effect you'll  have a cylinder full of round rocks  .  Concrete an inlet & outlet riser at each end such as using the blue 45 gallon drums with tops & bottoms cut off   Using spare material off drums cut 8 inch wide joining strips / patches bolt them together  ensuring that the top most drum at each end still has the thick rim on it  so you can attach a fan set at each end .

Fill the trench initially with about 500 mm of small round grit up to5 to 10 mm dia so as to not puncture the polythene.  At the risers  use greased /soaked in  veg oil wood to make shuttering a foot deep that can be unbolted & reused time I time again . I'd make the shuttering in two halves so it was a square frame  holding two semicircles tht would go round the riser tubes with about 6 inches to spare all round , then cast a foot reinforcing ring directly round the riser .  Once dry unbolt it back fill by hand to level with the cast concrete   ,refit the casting forms & repeat till you are at ground level ..  That will stop the barrel tube collapsing & allow you to stand at the side of the riser in safety .

Fit the biggest variable speed fan you can get hold of to a board of ply so it just fits on the rim of the top of the barrel . make a safety grill the same size I fit securely it to the other end to stop youngsters climbing down in the riser or chucking stuff down the hole .

Over the end riser that in snot in the growing area effect a shade cloth out of a loose Hessian or cotton cloth above the riser about 1.5 mtrs above the fan and make it around 5 x 5 mtrs square , put it on chicken wire if needs be to support it .

Above this cloth arrange a sprinkler on a time clock so you can spray water for a few minutes at a time several times an hour 24/7 .  This is the basis of the early air conditioners  as used in department stores in the USA in the early 1900's  water evaporating off the cloth will see the air temp drop 2 to 4 oC lower than the ambient air temp .

Now turn the fan on to suck this cooler moist  air down into the underground heat sink .
Once the air is fully drawn through it should be a nice even coolness several degrees cooler .  
So at the growing end of the device put up more white cotton sun  shades to reflect the sun,  adding  a few cotton deflector  walls on posts to direct air flow around the growing area. An outer wall almost up to the cotton roof  should allow containment of the cooler air .

There might be a secondary cooling above th crop area when the cooled moist air hits the sun shade cloth .
Another thought is .... Could you use home made 2 foot diameter tunnels of cloth & wire turned like long springs to direct cooled air ?
 
It might be that during darkness you can get he heat sink rocks even cooler for a few hours use at the hottest part of the day . so having a permanent temperature reading device at the air out riser could be very beneficial .


Now after typing in all that ........ Shade cloths on a wire support frame over the growing area  sprayed via a time clocked spray & let the sun evaporate the moisture ..   You'll have to make a test rig & see what temps can be obtained . Perhaps putting a half wall all round the growing area to slow air movement .  Adding an oscillating  fan pointed towards the damp cloth  should help the cooing, so again do your trials  & always but always keep detailed records so you can learn if it works & how cost effective it is  .


The old brain has stirred yet again ....
When I first started looking at using the ground as a heat sink or heat exchanger some 40 years ago I came across the word  " Coolth "  .
Where people were burying deep down  plastic water pipes in a looped system , using 12 volt vari speed pumps to pull in the cooler water.  It was then passed round rooms via good old fashioned radiatorsset in wall mounted cabinets that also had 12 volt vari speed fans to blow warm air across the cooler radiator surfaces

I think the  Israelis have done a lot of work in this area  ,  it may be that solar panels to supply the electrical power are included these days  .

Thanks everyone for your inputs.  I think my best answer is to just build the earth tube system alone first and see what kind of results I get.  If that isn't enough, I can always look into additions to it.

This man did the air flow through rock bed and solar powered it.

David Gould wrote:

Chris Kridakorn-Odbratt wrote: A very cheap and very efficient system, for heating, would be to bury a coil of black tubing in a compost heap. Then, with a small pump, run more black tubing in the soil and maybee also on the walls (of the grenhouse), and circulating back to the compost heap. No water loss, everything (almost...) above ground = easy maintenance...
Just be careful, with to much heat ( it can easily get over 70 C, aka 160 F ).

Anyone has experience in cooling ? I live in SE Asia, and we always have problem, with cooling ( 0 problems with heating ;o)
Cheers, Chris

Chris Your request has stirred my old grey matter into a riot of ingenuity..........  I suspect you could do do what you have suggested in reverse , kind of thing  , so one end comes up in the growing area .  I don't know how efficient it would be .

Thanks David - Great idea !
But I think a bit expensive... Round (river) stone are very expensive here, and difficult to get hold of.
Some years ago I installed a very fine mist system on a large verandah ( aka Olympics in Atlanta usa, and world trade fair in Barcelona, Spain). The main problem was that the ambient temperature neded to be above 36 C, 100F, othervise you just got wet. But the few days we had those temps, the temp was lowered by 12 - 15C !
I think I will do some experimenting with some kind of hybrid system - yours and the fine mist... Will see when I move back to Thailand, later in the year.
Cheers, Chris

Chris ,
Think differently instead of smooth river rocks why not use wine bottles filled with water & plugged with a plastic cork . They will eventually take on the surrounding temperature .
Just think of the fun you will have as you and your friends collect & empty the bottles .

Stand them up right , use a non rotting separating sheet between layers & cap top row with the same no rot sheet before covering with the waterproof membrane  
Perhaps plenty of plastic crates inverted over the bottles is the answer to getting the rot proof " Floors " on top of the bottles .

It is actually not al that new AND you can use to cool things !


https://en.wikipedia.org/wiki/Geothermal_energy

Others above have mentioned pumping warmer groundwater out of the ground. That's just one way of doing this. Perhaps not the best to have a long lived system. Open systems may clog up due to mineral buildup.

You do not actually need water to harvest geothermal warmth. Over here we have semi-deep wells into f.e. the Ypres clay (= London Clay) between 60 and 100 m deep where heat is extracted to power professional greenhouses. Some of these use wells use glycol as a transfer medium.

Other types of geothermal energy harvesting use the provençal (aka Canadian well) or shallow geothermal systems (f.e. a horizontal tube system under a lawn). A horizontal system with a liquid heat carrier takes room and cannot be combined with deep rooting plants.

To self construct a Canadian Well shows most promise in my opinion. Acquintances of us, use a Canadian well to bring outside air through the soil into their loam stove. This reduces their heat bill some more. I have included some links, most in dutch - Use autotranslate or follow their included links.

http://www.meeroverepb.be/pages/kdb.php?id=216
https://www.ventilatiesysteemabcd.be/aardwarmtewisselaar-canadese-put
http://www.be-green.com/nl/news/eco/zelfbouw-een-canadese-put-of-aardewarmtewisselaar-_59/
http://wesconva.com/products/geothermal-energy/
https://geothermie.vito.be/en

Check this info out. https://www.youtube.com/watch?v=6SD5HpXZc1w