geo thermal hot water

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geo thermal hot water

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joker

Joined: 08 Nov 2004
Posts: 188
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Posted: Thu Mar 03, 05 10:32 am Post subject: geo thermal hot water

I have just read the article on solar hotwater and wondered if anyone here had heard of the water heater that uses heat from the ground i cant remeber for the life of me what its called but anyway my idea is manure heaps seem to get hot on their own and ive even heard of them self combusting so why not instal a heat exchanger of some sort in the manure heap i cant test this theory my self as i dont have a manure heap

judyofthewoods

Joined: 29 Jan 2005
Posts: 804
Location: Pembrokeshire

Posted: Thu Mar 03, 05 11:05 am Post subject:
Geothermal is out of the reach of individuals, unless you have hot springs in your garden. Its only viable on a community level. There is a way of using the heat from compost, the Jean Pain method, here a couple of links https://www.daenvis.org/technology/Jeanpan.htm https://journeytoforever.org/biofuel_library/methane_pain.html

joker

Joined: 08 Nov 2004
Posts: 188
Location: hiding

Posted: Thu Mar 03, 05 12:03 pm Post subject:
CHEERS Judging by what i just read on that link the idea would work and i supose the methane given off would explain the compost heaps self combusting aswell . The only thing i am a bit unsure about is that 50 tonne storage tank they have used not sure the average house has got the space

judyofthewoods

Joined: 29 Jan 2005
Posts: 804
Location: Pembrokeshire

Posted: Thu Mar 03, 05 12:09 pm Post subject:
there is always room for experimentation. I would just use the info as a starting point. One experiment I can save you though, is, don't use aluminium vent duct pipe. A firend tried it, and the ali corroded in next to no time with the acids in the heap.

Treacodactyl
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Joined: 28 Oct 2004
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Posted: Thu Mar 03, 05 12:17 pm Post subject:

There is a system for taking the heat out of the ground to use. Basically you burry a pipe a few feet under the ground and water is pumped through. The temp raises a few degrees and a heat exchanger takes the heat out to warm your house.

There was an article in Country Smallholding a while back. More details can be found at CAT.

I've always liked the idea of using a good compost heap to provide heat to a greenhouse or conservatory, especially if you have a reasonable amount of animal waste. It's something on my list when we move.

joker

Joined: 08 Nov 2004
Posts: 188
Location: hiding

Posted: Thu Mar 03, 05 12:19 pm Post subject:
cheers i think that stainless steel will be my first option i am just thinking of exploiting the methane at the moment that should be a fairly easy start some sort of stainless steel sealed compost bin and storage tanks of some description for the gas . I supose i could wrap a copper coil around the bin to heat water

judyofthewoods

Joined: 29 Jan 2005
Posts: 804
Location: Pembrokeshire

Posted: Thu Mar 03, 05 2:17 pm Post subject:

copper would also corrode very quickly, but perhaps you could paint it or wrap it in something. How about digging a pit for the compost, the earth would give it extra shelter, if your watertable allows it. Do you also want biogas from it? Have a look at this forum, it has a section on biogas with some good ideas for digesters
https://www.green-trust.org/forum/
and there is an article on this blogg
https://www.green-trust.org/blogarchive/2005_01_01_archive.html

An e magazine (looks like there is a hard copy too)
Energy Self Sufficiency Newslatter look good for off-gridders
https://www.rebelwolf.com/essn/ESSN-Feb2005.pdf

judyofthewoods

Joined: 29 Jan 2005
Posts: 804
Location: Pembrokeshire

Posted: Thu Mar 03, 05 2:20 pm Post subject:

Treacodactyl wrote:

Yes, this system is feasable on a domestic scale but still very expensive and requires a lot of digging and pipe. Strictly speaking its not what is called geothermal, which involves very deep drilling.

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Thu Mar 03, 05 3:47 pm Post subject:

judyofthewoods wrote:

True geothermal is indeed heat from the earth's core - its viable in Iceland and other volcanic regions but not really here.

Unfortunately the 'geothermal' tag has been borrowed by those selling systems using the ground both as a solar (heat) collector, and year-round, day and night heat store.
A cold fluid is circulated through the buried pipe and returns warmer. This is circulated through a "heat pump" (that works rather like a fridge) that strips the heat from the fluid and 'upgrades' it to a higher temperature.
For every (paid) kilowatt of electricity the heat pump uses, between 4 and 6 kilowatts of useful heat are captured... so these systems can be cheapish to run, although expensive to install.
Unfortunately, the heat pump efficiency drops off as the temperature uplift increases. This means the system is best suited for underfloor heating. And you are likely to need a few hundred metres of pipe buried about a metre down - this can be done with heavy equipment, but your garden/paddock is going to take a pounding!
For these reasons, its only really suited for a new build, where excellent insulation can be installed (minimising the system size), and the groundwork and underfloor installation wouldn't be a problem. Economically, in such a situation, it can be better than oil over perhaps 15 years. Carbon-wise, its better.
Putting the collector circuit in a stream or lake makes an even better prospect. It works pretty well where there's a lot of groundwater.
Some varients involve drilling vertically down, rather than shallow burial of pipe - but still the true origin of the heat is solar rather than geothermal.

Treacodactyl
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Joined: 28 Oct 2004
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Location: Jumping on the bandwagon of opportunism

Posted: Thu Mar 03, 05 7:24 pm Post subject:
Yes, that's more or less what I gathered from the article dougle. I'm not keen on the idea of installing the equipment etc. But, I have wondered if a system can be made running pipes through a manure heap to heat a greenhouse or even a conservatory. I've tried putting the manure in the greenhouse but the gasses given off were harmful to our plants, so a pipe system would be useful.

judyofthewoods

Joined: 29 Jan 2005
Posts: 804
Location: Pembrokeshire

Posted: Thu Mar 03, 05 7:29 pm Post subject:

Treacodactyl wrote:

But, I have wondered if a system can be made running pipes through a manure heap to heat a greenhouse or even a conservatory. I've tried putting the manure in the greenhouse but the gasses given off were harmful to our plants, so a pipe system would be useful.

Have a look at those webpages mentioned at the top of this page on the Jean Pain system, which is what you discribe, using pipes in compost, as well as producing bio gas. Try another search, I just tried google, but another one might come up with more on Jean Pain.

Treacodactyl
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Joined: 28 Oct 2004
Posts: 25795
Location: Jumping on the bandwagon of opportunism

Posted: Thu Mar 03, 05 7:32 pm Post subject:
Thanks judy, I will. I've had a very quick look but I'll take another look over the weekend. It does look possible.

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