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Temperature Control in Orchid Boxes

Discussion in 'Growing Areas' started by Clusty, May 9, 2016.

  1. Clusty

    Clusty Member

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    Hello,

    I am in the process of finishing my fist orchid box.
    I got most of the gear sorted apart from heating/cooling of the box. The box is about 60"x30x30.
    The box is located in my basement which is always 18-21deg, basically lukewarm.
    How can I insure the day night temperature difference?

    Would heating work with heat mats (with enough air movement), or I need to drill my box and blow hot/cold air ?

    Also, did anybody try Peltier coolers/heaters ?

    Thanks for the help.
     
  2. carl

    carl Active Member

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    What temperature range do you want? Lighting should raise the temperatures somewhat when on, and provide some difference, especially if the light sources are inside the box. Separating the power sources from the lamps will allow you to moderate temperature gains.

    If you are on a quest for cool, you could use an aquarium chiller timed to run overnight, pumping chilled water through fin tubes in the box.

    Can Peltier devices move enough heat to be worthwhile? They aren't that efficient...
     
  3. Clusty

    Clusty Member

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    I have separated the lights from the growing area.
    I was pondering growing masdevalias, so I guess I am going for a 10degree differential day-night.
    I saw Peltiers in the 200W range. I guess the main issue is dispersing the heat/chill fast enough ( could get frost forming on it )
     
  4. Ray

    Ray Orchid Iconoclast Supporting Member

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    If you are lucky enough that natural cooling is sufficient, placing a heat mat on the bottom (connected to a timer) is sufficient to heat it up.

    For Peltier coolers to work well in a tank environment, they need to be tightly bonded to a pretty good sized heat sink, and have a fan actively blowing on them, so that there is a large volume of slightly cooled air, rather than a small volume of very cooled air.
     
  5. carl

    carl Active Member

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    So, CPU cooler with fan mounted on both sides. Probably would help to have it up high in the tank...
     
  6. Clusty

    Clusty Member

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    My plan for peltiers was to cut through the side walls ( melamine ) and have the unit sit halfway in, halfway out.
    Alternatively use gear for water colling CPUs and just have a small hole for the water hoses.
     
  7. Ray

    Ray Orchid Iconoclast Supporting Member

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    I haven't but a PC in a while, but aren't CPU coolers just heat sinks with fans to disperse the heat?

    I think the thru-wall idea is a very good one.
     
  8. carl

    carl Active Member

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    Most CPU coolers are just heat sinks with fans, but you can also get systems that have heat sinks with water chambers, plumbing, a pump and radiator on the outside. I suppose you can hook 'em up backwards, with the radiator on the inside of the box.

    But, the through-wall idea, with CPU heat sink and fan on both sides, is what I would do.
     
  9. KellyW

    KellyW Orchid wonk Staff Member Supporting Member

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    The CPU coolers with heat sinks, radiators, fans, etc would only be effective to equalize the temps inside and outside the tank. So, without something actively cooling air below the ambient temperature that is the best you could achieve with that setup.
     
  10. Clusty

    Clusty Member

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    There are fancy CPU coolers with Peltier elements:
    On top of the CPU you have the Peltier with 2 water pipes taking the extra heat away to some bulky heat sinks with fans.
    This way you move the bulky part away from the tight spaces ( in my case the box ).

    The beauty of peltier is that if you wire it backwards the hot and cold plates are reversed, thus an universal low efficiency AC/Heater.

    Thanks for all the help guys.
     
  11. Clusty

    Clusty Member

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    Ok, Got a few more questions regarding the box:
    How much air movement would you suggest for the box?
    I had a 25CFM fan around but it does not seem even close to enough air movement.
    Do I need to pipe fresh air into the box, or can I make it a closed system?
    Also, got some suggestions for shelf layout inside, for optimal space usage?
     
  12. Ray

    Ray Orchid Iconoclast Supporting Member

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    The idea is a buoyant, tumbling air flow, not a "breeze", per se.

    Yes, you'll want some fresh air exchange.
     
  13. crazyplantguy

    crazyplantguy New Member

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    The only issue with the pelt that I would have is they take alot of power. What size pelt would you use. That is a large box you are trying to cool/heat. Basically a fridge. I cant see not having to use a 300-500 watt pelt. You power bill for running 24 hours is going to take a hit. You can use a cpu fan controler to adjust temps just make sure it has temp sensors you can mount you can adjust fan speeds on the heat sink to adjust temps i would water cool it. it will be less noisy. I wouldn't recommend reversing polarity due to the size of the pelt you would need. Unless you plan on it having a melt down. You have to be able to move the heat fast. a pelt never reaches a stop point it just gets hotter and hotter and hotter. Until it melts and trust me my fingers can vouch for that. The heat sink on the cold side would not be good enough to be used as a hot side. It would just get to hot. If it was a small box like a 2.5 gal or 5 gal size a pelt would be awsome. But your box makes thing more complicated. Jmo but I would love for you to try and see what you come up with it is possible you just have some issues to work out. Good luck
     
  14. Dave The Scientist

    Dave The Scientist Active Member

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    You could fab up some type of evaporative cooler. All it needs is a fan and a pump so much cheaper to run than a Peltier.
     
  15. Clusty

    Clusty Member

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    I though evaporative coolers needed low ambient humidity. If my tank is already at 80%, not sure how much evaporation is going to happen.
     
  16. Ray

    Ray Orchid Iconoclast Supporting Member

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    Evaporative coolers are ideally arranged so that they take warmer, drier, outside air, and propel cooler, moistened air into the enclosure.

    However, I've seen swamp coolers function well inside of a greenhouse in Houston, so at 60% RH, it would probably still have some effect.
     
  17. Clusty

    Clusty Member

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    problem is if I am pumping too much air from my room inside the box, my room will wind up becoming a swamp itself since the wet air will get out.
     
  18. Dave The Scientist

    Dave The Scientist Active Member

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    If you keep the door open, it should dispersed well enough to no be a problem
     
  19. Ray

    Ray Orchid Iconoclast Supporting Member

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    If your room is totally sealed, then yes, you're right. Otherwise, I wouldn't worry about it.