One Massively Crazy Idea

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I hope you are all sitting down because I had this crazy and wild idea for heating my house. You see research has shown that solar, wind and geothermal systems just don't work very well here in Maine. At least the return on investment is so long that fossil fuels work out better.

So I got to thinking. If the ground is not warm enough by itself to heat my radiant concrete slab, why not create warmth, but without fossil fuels. Now we all know that compost piles generate heat...lots of heat, so why couldn't I create a compost pile, run PEX tubing through it, and then circulate water throughout the compost pile to warm the water which in turns warms my radiant floor?

Now this sounds crazy I know, but I don't think I need boiling water to warm my floors, just 80 degree water or so. I think a compost pile would get temps well above that. I also know that on the farm our haylage pile stays hot all winter long. So hot that its all you can do to stick your hand in it. For the cows they love the hot meal, but for me, I am thinking I might be able to tap into that natural heat source.

This is just a wild and crazy idea, but my thought is to create a small haylage bunker near my house. A little ways off, but not too far. Anyway I would haul in a few truckloads of haylage in the fall, run pex tubing through the pile, pack it down with my tractor, then cover the top of the pile with insulated panels that way the heat is retained. I am thinking maybe once or twice in the winter I would have to mix up the pile to keep it churning, but I am not sure. The good thing is, the cost for this would be rather minimal, and I have the machinery and land to cut all the haylage/sileage I need even if it meant several truckloads.

A friend at work claims it would not work because "if I thought of it, someone else has too and proved it would not be feesable." I am not sure I agree with that short sighted statement however. Wood splitters did not become mainstream until the oil embargo of the 70's even though tractors, hydraulics and hydraulic rams were around long before then. So anyway at the cost of sounding like a complete moron, I thought I would post this idea here.

A picture of our haylage operation last year in case some of you don't know what haylage is...

Haylage.JPG
 
that could work travis.....i`m thinking that you`d want to pour a floor and walls and place your pex in the floor, you`d have a large heatsink that you could drive the tractor on so you could turn the pile..... why not build a wood fired boiler to where you could supliment the heat generated by the composting hay? it`d just be a matter of valving to either call it into play or isolate it.....
being as you have access to equipment a coal fired boiler is much more efficient so long as you`re not paying to have the coal hauled.....
any way you go you`re going to have a few thousand bucks tied up in a system, so if you do try the compost idea pour the floor-n-walls to a size that would make a good outbuilding if the experiment fails. you`d allready have the floor plumbed for heat;)......sounds like an idea worth looking deaper into.
 
Not so crazy an idea

This may be a great idea. I read some articles about this and it seems you can get water heated close to 145 degrees in a compost pile.
Be sure and post your progress.
 
You will generate a great deal of heat just maintaining the pile. Body and sweat heat, that is. :rolleyes: IMHO, you won't recover enough, if any, heat to make the project worthwhile. BTW, a geothermal, ground source, heating unit will work. Pipes are sunk way down in the earth and the heat is recovered for the home. Mine is great, very low utility bills. Where you live, it might not provide all the warmth you need in the very coldest weather.
 
Travis, I think that it would work and will be very interested in hearing more about this. If I were you, I would set up a small experimental system and try it this winter. I am sure that you will learn from this and then build the real thing even better next year.
 
A heat source is a heat source. The only thing I see as being a problem is collecting the heat from the hay, or compost for that matter. I don't fully understand how you store it, if it is in bales, or just piled in a big heep. Tod's response makes me think the latter in a barn, on a concrete floor, thus the pex in the floor so your tractor could ride over it without damage. That doesn't sound like it would be the most effecient collection of the heat, as the heat would want to go away from the floor, but it should capture some of it. It would be best to have the collection tubes in the middle of it for best collection, but that doesn't sound like a workable solution at all. Or imbedded in something that would naturally absorb the heat and transfer it to the lines. Copper lines, or at least metal of some sort, may be better to collect the heat.
Keep us informed if you proceed or at least do some experimenting with it. Sounds like it has some very workable possibilities if the particulars can be worked out. Good luck with it! Jim.
 
Travis,

Yes, it would work... people have been doing something like this for centuries, in other contexts. It's how gardeners used to make hotbeds, as opposed to coldframes. The problem you'd have would be keeping a steady temperature in the pile... it can make 170 in there, easily... but could just as easily be 120 the next day. :(

Oh, and did I mention that it *will*, at some point, catch fire? Ever had to put out a compost fire? Trust me, it's tons of fun... :doh:

I still think your best bet is to run your well water continuously through your slab... that would give you a geothermal system for pennies on the dollar...

Thanks,

Bill
 
Hi Travis, Whether your idea works or not as you will do it remains to be seen, but for now the most exciting thing is your idea and your excitement. They are both stimulating! Good for you!!! :thumb:
Remember, mark my words, some day we will build a boat and prove that the world is not flat!:D
 
The only thing I see as being a problem is collecting the heat from the hay, or compost for that matter. I don't fully understand how you store it, if it is in bales, or just piled in a big heap.

Haylage is quite different than hay. Hay is cut, allowed to dry out in the field, then baled up when the moisture is out of it. Without moisture that is why it keeps for so long...but also why the cows don't give much milk from hay feedings.

Where I live, hay is all but a thing of the past. We feed our cows haylage which is grass freshly chopped up. Think of it like lawn clippings that you bag up. Its green and laden with moisture so the cows give more milk. A lot more milk. Its hard on their stomachs so we spread a bit of hay over the feed to settle their stomachs after having haylage, but its not a lot.

Haylage is stored in silos or bunkers. Bunkers mostly. It is packed down with a tractor to keep it from rotting. If I was to use this type of compost to make heat, I would want it packed, but not packed to much. As is a haylage pile gives off lots of heat. On cold, cold days we would dig it out with a tractor and the steam cloud would be so thick that you could not see a thing. I don't know what temp it was, but it was always hot to the touch. The thing is, it was that hot after being in a pile all winter. No stiring or anything and packed down tight so it would not spoil. To me that's wasted heat.

As I said, I am not sure it would work, but it would be easy to do some testing. A local farmer has a composting business. I know he can tell me how hot it gets and maybe a bit more information on the subject. He does not use haylage, but does use a lot of fish tailings that come off the local fish plant. I also know he has to water the compost to keep it cool because it will burn off the nutrients if it gets too hot.

I am thinking the system might work. Sizing the haylage pile to my heating needs may be the biggest challenge. Dealing with the smell may well be another. Of course here in Thorndike Maine the cows outnumber the people by 10 to one so the neighbors won't complain. :)

As for the cost, I am thinking I could keep the cost down by doing what the farmers do. Build the bunker in the side of a hill. That means less concrete to purchase. A few thousand feet of PEX tubing and some circulating pumps and that would be all I need. Well maybe a lot of black plastic to cover the top, and plenty of tires. Again that is what the farmers use around her to cover their haylage piles.

Here is a picture of a silage bunker I pilfered off the internet just so you can see what one is:

800px-Silage_tractors.JPG
 
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Sounds like you have some technical issues to work out, but I don't see why it wouldn't work. If you are generating heat and can tap into it, you can make it work for you! Keep us posted on this! I, for one, will find it quite interesting!
 
Not crazy at all, I've read many examples of this working, though they're usually heating greenhouses and things since they're trying an experiment to see if it works before deciding whether to retro fit a house for radiant or not. It sounds like you're better equiped than most to make use of a huge pile - I'd have a lot of trouble with a pile big enough to heat a house, not having a tractor. Thats probably also why you don't see it implemented often - lots of work unless you're already a farmer.
 
I don't think you're crazy at all. Even if you can't supply all your heating needs from the compost generated heat, all you have to do use enough heat to offset the setup costs and you're ahead. Anything after that is a bonus.

I'd also like to hear how you make out - keep us posted eh?

cheers
 
I probably won't do much with this as of right now. I still have a big list on my house to complete before heavy weather sets in, but I might be able to get in a small bunker, fill it with haylage and cover it back over. With a temp gauge stuck inside it, I could see what it does heat wise over the winter.

That would be a fast, quick way to tell if it would work. As with anything I do, researching the project is almost as fun as actually doing it. But yeah, I will keep you all posted.
 
Heat from our outside wood boiler isn't warm if the stove/water temp is below 120? (HEY, I FOUND THE ? SIGN!!!!!!!) 80? won't send much heat your way. Do know an old guy that kept his stock tank inside his barn from freezing by building a box out of plywood and covering it with fresh horse manure. On really bad winters, he would replace the manure in the middle of the season. Kept a small area with a lid that hinged up so horses could drink, otherwise lid was closed and no ice, not even a skim.
 
One thing to think about is that I believe you would get much more heating of the water while it is in the hayledge bunker if you use copper or aluminum tubing and then connect that to the pex where it leaves the bunker and use the foam pipe insulating tubes around the Pex to transfer it to the house to minimize the heat loss during transit. The copper or aluminum I believe would have a greater heat transfer coeffecient than the Pex. I don't know, however, how well the copper or aluminum would endure the moisture and chemical reactions in the hayledge, and might be short lived due to corrosion unless coated with an anti corrosive paint.
 
Heat from our outside wood boiler isn't warm if the stove/water temp is below 120? 80? won't send much heat your way.

Radiant floor heat is much different than baseboard heat where water is trying to heat the air to make the room warm. With radiant floor heat, anything over 90 -100 degrees gives you hot spots in your fllor and room. It also depends on how much you circulate your water. You can give it a burst of 120 degree water and then let the slab warm up quick and cool off without circulating water, or you can constantly circulate 80 degree water and keep it at the same temp. It all depends on how your system is set up.

My father has had both. He had a huge outside wood boiler that ran hotter water in cycles, but in his new house he has a oil fired boiler that circulates 80 degree water constantly.

Here in Maine the outside boilers are on their way out...almost outlawed now. If smoke blows across your neighbor for more than x number of days and he complains, it must be moved or shut down by law. A lot of people have them here and its becoming a real nussience, hence the new laws regarding them. Myself, I am not a fan. I watched my father go from burning 12 cord a year to burning 22 cord a year. It was a 365 day a year heating system. He was either putting wood in the thing, taking ashes out, getting wood for it, trying to find wood, or trying to figure out where his next jillion cords of wood were going to come from. Then the darn thing burned his house down!! As I said, I'm not a big fan.
 
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I probably won't do much with this as of right now. I still have a big list on my house to complete before heavy weather sets in, but I might be able to get in a small bunker, fill it with haylage and cover it back over. With a temp gauge stuck inside it, I could see what it does heat wise over the winter.

That would be a fast, quick way to tell if it would work. As with anything I do, researching the project is almost as fun as actually doing it. But yeah, I will keep you all posted.
Travis, I am with you about the fun of research and experimentation. I hope that you do this and will be interested in the results.
 
We use our outside boiler for three things, heating our domestic hot water, in floor heat in the new addition (24X24), and for forced air heat (running through the old furnace ducts and blower capturing the heat of the water and running it through the duct work).
Interested in how an outside wood boiler burnt his house down Travis.
 
Not very interesting at all really. The boiler had defective wiring that short circuited. The sparks dropped down into the sawdust that accumulated around the pile of wood he was feeding his boiler. That caught the pile of wood he had stored next to it on fire, which was a pretty good pile of wood (he burned slabs that came off our sawmill as this was the summer time). Anyway that got big enough to melt his siding and eventually catch his house on fire, all at 3 AM in the morning.

He had a split level home so the fire hit the garage, traveled up the walls and soon he had fire in the attic space, and in the garage below. They were really lucky to get out alive. They never heard the smoke detectors, though the oxy-aceletene tank in the garage exploding woke them up and he got himself, the wife and three kids out. (They are a foster family so even at an older age they have little ones in the home).

The dog near died, but he got her out (a basset hound) and eventually his tractor too. It was so hot it melted the plastic trim on the tractor and he burned his fingers turning the key on. Luckily the tractor was saved though. Just about everything else was a loss unfortunately. They had good insurance so in the end things turned out for the better, but my Mom made it clear the new home would not have any wood fired heater or any type.

Myself, I disliked his wood boiler from day one. Whenever he was not home I had to feed the thing, or help him get wood for it, or find wood for him to cut up for it, or put up with the choking smoke that blew all the way up to my house. To me it just was not worth the effort and when it finally burned his house down, it proved once and for all there has got to be a better system out there.

I am thinking that the wood boiler heats the water too much, just as propane and oil fired boilers do. I was thinking along these lines when it occurred to me our sileage pile was always hot from the decomposition of the hay and corn inside it, but not super hot, and that if it stayed say 100 degrees all winter long, why not draw off that heat source? That was my line of thinking anyway.

As someone else said, probably the main reason its not used is because for the average citizen, even one in rural America like me, it would not be feasible to collect enough haylage to make it worth it. You would need ample hay or corn ground, equipment to harvest it, and a way to collect it. I just happen to have all of that so it would be interesting to see if you could potentially heat your home off what amounts to a big composting pile.
 
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