Keith Addison
Mon, 22 Sep 2003 15:49:33 -0600
Hi Hakan >Keith, > >Using compost or rather animal manure for space heating is >a very old method. If you study old traditional farm buildings in >colder climates, you will most of the time find ways of using >the heat generated. The simple and most used way is to stack >the manure against walls that directly transported the heat to >the living space.
This IS an old traditional farm building in a colder climate... but you have to go much further north to find energy-efficient old buildings. Here they huddled round a little island of heat created in the middle of the living room and otherwise just suffered. Elsewhere, I guess the traditional hotbed for growing vegetables is one of the commonest uses of manure heat - there are details here: http://journeytoforever.org/farm_library/device/devices6.html These are all direct-heating methods though, not suitable for us, and we'd need a lot more livestock anyway. By the sound of it, Caroline also only has chickens, probably not enough for this sort of application. >Cheap plastic hoses are very sufficient in transporting heat from >a compost to a living space. They have resistance for temperatures >below 60 degree Celsius and will work well. You can use the same >pipes under a floor, to create a large radiant surface and with the >house floor above the compost you will not need pumps etc. I'm thinking of under-floor heating but it'll take a lot of water, much more than the compost would provide. You do mean the level of the house floor would be higher than the level of the compost? I think you puzzled Caroline. >In your case, with poor insulation, large radiant surfaces is the >best and most efficient way to achieve comfort at low air >temperatures. > >An other question is dimensioning and if the composts are large >enough to provide the heat in the space size. That is the question, yes. >You will anyway >get a base portion of useful energy for nearly nothing. Yes! For nothing maybe, except time and labour, if I can get away with only using recycled junk. Thanks Hakan. regards Keith >Hakan > > >At 12:58 PM 9/21/2003, you wrote: > >Hi Caroline > ><snip> > > > > >Then there's a > > >constant 60+ deg C heat supply from two one-cubic-metre compost piles > > >(in series), > > > > > >So how exactly are you "harvesting" this heat to heat a home? > > > >We're not, yet - as I said, it's one of a number of heat sources > >we'll be harnessing this winter. It won't be enough to heat a home. > >Especially not this home. Which isn't exactly a "home", it's a sort > >of barn/shed/workshop/studio/lecture room/office with some living > >space in between, and it's quite big, and extremely > >energy-inefficient (it's a 100-year-old traditional farmhouse that's > >been more or less neglected for 30 years) - not too bad in summer, > >really bad in winter. The compost heat will help, even though it's > >not nearly enough. As I said there are a lot of bits in the puzzle > >and we'll figure out how to fit them together as we go along. It > >might be more effective to use some or all of the compost heat to > >heat the biogas digester, for instance. > > > >At any rate we'll use it to heat water, and use the hot water for > >whatever. I have used the heat of a compost pile before, but not > >systematically. But it works. I always make compost, wherever I am, > >and for years I wondered why nobody used the heat, but I wasn't in a > >situation where I needed it or would have been able to use it. Then a > >few years ago I found that some people at least were using compost > >heat, at last. One system coils plastic hosepipe into the pile as > >it's built up and uses convection to move the hot water. A bit > >primitive, but that'll work. We'll do something similar. At least one > >of the two piles is always above 60 deg C (up to 75 deg C). The > >weather doesn't make any difference, it can be well below freezing > >but they'll still get hot. Yes, I know, each time I say this someone > >objects: "Not where I live, it's much too cold here, it just > >freezes." Sorry, but that's tantamount to saying: "I don't know how > >to make compost." Then they might propose getting it to work by > >providing an external heat source to heat it up artificially. Nope, > >that's not how compost works. There's a photograph in the Rodale > >Encyclopedia of Organic Gardening of someone making compost in the > >snow. Been there, done that. > > > >How much heat does a composter produce? In other words, how much can > >you harvest before you kill it? I'm not even sure that's a real > >question - it is a physical process, oxidation of carbon, a slow > >fire, but it's biologically driven: given the moisture and the air > >supply the microbugs will go on doing it until the C:N ratio > >stabilises (from about 30:1 to maybe 10:1 or something). But if you > >take too much heat out the temperature could fall below the > >thermophilic level and go mesophilic, no use for thermophilic bugs. > >This is something we need to learn more about, and that's our real > >purpose here now, more than just to heat our house. This is the final > >trial-run for our journey, where we figure out the detail of the > >technology we'll be using as much as possible, what we don't already > >know of it. There's much more to it than just alternative energy. > >We're doing well, we've covered a lot of ground already and learnt a > >lot, but there's still much more to do. > > > >Anyway, I'll probably post further info about all this as it unfolds. ------------------------ Yahoo! Groups Sponsor ---------------------~--> Special Sale: 50% off ReplayTV Easily record your favorite shows! 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