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Thread: Interesting hot compost design wheelie for fish tank.

  1. #1

    Default Interesting hot compost design wheelie for fish tank.

    Been trying out the 18 day hot compost in the backyard,
    -http://deepgreenpermaculture.com/diy-instructions/hot-compost-composting-in-18-days/

    And then came across this - http://permaculturenews.org/2010/01/...t-wheelie-bin/

    Thought I would share it on the forum, not something I would attempt at home as partner "will" be annoying at me making bigger compost. I quote " can we just not do that. " Interesting though.
    Would like more pets.

  2. #2
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    I tried this...
    it is great in theory but not really great in practice unfortunately..
    you really need to have a big capacity to really generate enough heat...

  3. #3
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    Interesting but no way are you going to get enough energy from that amount of biomass. Maybe if you had it set up in full sun with the dark colour of the bin you could get more heat.
    Subwassertang- Proof that when enough people are wrong it's accepted as right.

  4. #4
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    Depanding on the material in the bin they can be hot to touch in a week,spontaneous combustion is something that can happen and some council bins are now being replaced with breating holes to stop the extra heat build up.

    I try cutting my grass on collection day ( bin just emptied) that way the volume of grass reduce's to around 2/3rds full and than can place extra material in bin for collection day to get 1 and a third bins worth of green waste taken away.

    I think the idea is good but would need temping switch before use.

  5. #5
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    Imagine the cost of running a pump to send water out to your compost bin and back, plus the thermostat etc. You would be better off buying a simple heater for $50.

    I read about a similar but opposite idea on a saltwater forum. The thread was about a guy pumping water through coils buried under his house to cool his tanks.

    In the end the cost of pumping the water through the coils was more than cost of running a chiller, so it wasn't really viable long term.

    I use rooftop solar heating for my pool. Now that would work well if you have lots of tanks or a huge tank to heat.
    Last edited by Waterman; 30-04-13 at 10:08 AM.

  6. #6
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    My uncles used to whack a bit of gal pipe into haystacks they were worried about so they could tell if bales were getting to hot. If you couldn't hold the pipe it was to hot and the stack needed to be pulled down. This was in the days of rectangular bales of course. The size of a haystack compared to a wheelie bin and the insulating qualities of hay make this possible. I have seen steam coming off big compost heaps in winter but that is big piles not just a wheelie bin.
    Subwassertang- Proof that when enough people are wrong it's accepted as right.

  7. #7
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    Best to leave the lid ajar if your worried about fire,the lid closed cause the extra heat for fast break down of the compost.

    You can also run them in plastic bottles etc to generate heat collection there's many hours of videos on solor heat generation on youtube.

  8. #8

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    The money spent on the bin would be about what you save in energy. This process on a small scale is very inefficient.
    Once you put a pipe more than one meter under ground it is at a constant temperature, Sydney is around 21 i believe, would work great for cooling.
    The rooftop solar heating is an excellent idea, but that heats water to around 65 degrees on a hot day and ambient on a cloudy day, not what you want in the middle of winter.


    Fire isn't an issue, autoignition of cellulose occurs at around 600 degrees, Methane a little lower, but still over 500. Bacteria dies well before 500 degrees is achieved.

    The best thing you can do with this is compost your foodscraps and then put it under the substrate of your next tank.
    Chris -my tank

  9. #9
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    I have seen steam come out of a prototype solar hot water system on cloudy days, not just a bit of steam come off a body of water but steam blasting out once the taps were opened. Check out absorber roof on Youtube.
    Fire is certainly an issue with hay stacks http://www.dpi.vic.gov.au/agricultur...ous-combustion
    Subwassertang- Proof that when enough people are wrong it's accepted as right.

  10. #10

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    I meant fire isn't an issue with the small scale compost heater.
    I personally have never seen a haybale catch fire, but i'm sure that it does happen, thanks for the link.

    The solar system claim is interesting, are you sure it wasn't just the product of gas expansion in the closed and pressurised environment that you saw?
    I don't doubt that they get hot, however the ability to produce 120 degree saturated steam on a cloudy day sounds a little far fetched.
    The heat flux from the sun is around 1000W/m^2 at the surface, fully sunlight day, this is roughly half visible, roughly half infra red. Heat capacity of water is 4.2kj/kg.
    Assuming 100% conversion, 230g per second of water will change temperature by 1 degree. But you need around 90 degrees delta t for water to become steam.
    This means around 2.5g of water is heated to around boiling per second per m^2. If you have a 20m^2 system, that's only around 50g per second.
    3kg a minute, PEAK, assuming 100% efficiency and no loss to environment, no interface with the air and no loss through radiation onto the roof or reflection off the panel.

    Definitely wouldn't say that a cloudy day could boil water unless we are talking a huge system with a slow turnover or a closed pressurised system.
    Chris -my tank

  11. #11

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    I cant remember the exact nature of the thread, nor find it, but I swear someone once mentioned using composted horse manure to heat a pond over winter..

  12. #12
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    Mr c265 this is something I have seen with my own eyes. It was built and designed by a friends son. He has a parabolic reflector focusing the heat and light onto an aluminium extrusion he had done with a very tiny hole through the centre and fins to absorb the energy. the back of the unit is made from a temperature resistant polystyrene and it has a polycarbonate lens on the front to trap the heat. The prototype probably boiled about 300 ml a minute from about 8x1.5m runs in parallel with water at ambient temp.
    Subwassertang- Proof that when enough people are wrong it's accepted as right.

  13. #13

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    My mistake, i assumed you meant a standard design solar hot water system.
    Chris -my tank

  14. #14

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    Would you "need" a pump??? have a look at -http://blog.makezine.com/2008/09/19/noelectricity-hot-tub/
    Have seen one of these tub in action back in the day, was in art school and they were making human soup at a outdoor camping party.
    Would like more pets.

  15. #15
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    May 2012
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    Old thread bump

    I thought there was a more recent thread on this @Rebel?

    In any case, has anyone tried something similar to this for a pond or tub?

    Cheers

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