DIY Greenhouse Heat Recovery System

Discussion in 'Designing, building, making and powering your life' started by tinyallotment, Jul 10, 2015.

  1. tinyallotment

    tinyallotment Junior Member

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    As my dome seems to actually becoming reality I am looking for a way to regulate the temperature both day and night.


    I am going to have some vents as a back up just in case the dome overheats but this would be a worst-case scenario. I do not want to loose the heat generated during the day. I would rather store it to be released over night.


    I'm sure there are countless commercially available systems out there but my system needs to be cheap and DIY.


    I'm thinking, a solar powered ducted fan taking the hot air down to a loop in an insulated IBC full of water and back out again.


    This should take hot air from the top of the dome, cool it and return it to the dome during the day. Come night time the heat will slowly leak back out from the water into the dome maintaining the temperature over night.


    Would this work?


    Paul
     
  2. John Morrison

    John Morrison Junior Member

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    Good evening
    I've seen thus design before and reckon it will work
    The system Geoff lawton has on his website geofflawton.com shows this system working in Canada and the air is blown underground. I've seen a design with the air blows through a gravel bed and exits at floor level and the plants growin on top of the gravel bed. That seem to work well too. Please check for your self to see if water or earth/ gravel works better as a thermal mass.
    Please also consider adding another warm element to your dome house to heat it at night a cage of chickens would work well too.
    Enjoy the ride
    John
    In
    Brisbane
     
  3. tinyallotment

    tinyallotment Junior Member

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    Thanks John

    The reason I will be using water is because ultimately I will be keeping fish in the tanks as part of the aquaponics system.

    I am building a monitoring system that will monitor all aspects of the system so if the water becomes too warm the heat will be diverted elsewhere.

    paul
     
  4. 9anda1f

    9anda1f Administrator Staff Member

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    I think your plan will work well Paul. What material will you be using for your duct loop? Water rates very well in specific heat retention compared to other common materials:

    [​IMG]
     
  5. Brian Knight

    Brian Knight Junior Member

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    Judging from the size of your dome, I wouldnt expect very much temperature stratification. So if youre going for truly cheap and simple, maybe make provisions, but not buy all the pieces until its determined to be needed. Perhaps the surface area of tank, in contact with the dome air is a bigger consideration?
     
  6. tinyallotment

    tinyallotment Junior Member

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    Thanks Brian
    I am hoping to sink the tanks into the ground if I can so there will not be that much surface area in contact with the air in the dome. This dome and all the systems in it are really just a dress rehearsal for our big dome that will be integrated with our home. We don't have the land yet so this is testing concepts in miniature.

    Keep the ideas/comments/criticisms coming though as I am learning this stuff as I go along and it is easy to just get wrapped up in a romantic dream world.

    Paul
     
  7. Brian Knight

    Brian Knight Junior Member

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    So if you are sinking the tanks in the ground, the Delta T (temperature difference) between ground and desired tank temperature becomes important. You will want to insulate between the two to prevent the ground from impacting its temperature too much. I would think a strong ground couple (no insulation) might be better in the summer to prevent the greenhouse heat from cooking the fish but in the cooler seasons, the ground would prevent the tank water from getting up to warmer, more desireable temps.

    Nothing wrong with romantic dreaming! I must say, integrating greenhouse/aquaponic is some fun stuff, but when you talk about integrating those with your living space and indoor air, that sounds a little more on the nightmarish side to me ;)
     

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