aquarium chillers

Discussion in 'Darkroom Equipment' started by Wayne, Apr 5, 2006.

  1. Wayne

    Wayne Subscriber

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    Pretty soon my troubles will go from needing to heat my developers to trying to keep them cool. Does anyone have any experience with aquarium chillers? I've been researching this for all of 10 minutes, but I found a relatively cheap type (they can run into the thousands for big ones) that looks small enough to mount in a large tray or tempering bath

    http://www.aquadirect.com/store/product.php?productid=195&cat=77&page=1


    but I have no idea how these work, or if they are even remotely feasible for this purpose.


    Wayne
     
  2. DeanC

    DeanC Member

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    If you're already doing something quasi automatic to heat (aquarium heater and submergable pump?) your tempering bath, why not just float some ice packs in it? The ice will keep it from getting above the heater set-point and the heater will keep it from going below.
     
  3. Magnus W

    Magnus W Member

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    These small units can be great, but:
    In small aquaria there sometimes are problems with the waste heat that the filter system and light system gives off. This little gadget can fix this.
    But it is not a true heat pump, and -- as the caveat in the description says -- does not lower the temp below ambient room temperature.

    I'm sorry, but I think you have to go for a bigger (and sadly, more expensive unit) like this one.

    aquarium dude too -- MW
     
  4. Helen B

    Helen B Member

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    I've begun the same search. The IceProbe is a small semiconductor device (Peltier effect) with about 50 W of cooling power. How well that would work would depend entirely on the heat gains to your tempering bath. If you insulate the sides of your bath, cover it and have plenty of water in it you might be in with a chance. Given enough time a unit could also cool an insulated water storage container. With time, adequate insulation and thermal inertia a small cooling unit could work. They wouldn't be able to get uninsulated units (eg fishtanks) much below room temp because the heat gains through the walls would be too high. Stop those conductive heat gains and the temperature will come down.

    Do you want me to do some approximate calcs?

    "If you're already doing something quasi automatic to heat (aquarium heater and submergable pump?) your tempering bath, why not just float some ice packs in it? The ice will keep it from getting above the heater set-point and the heater will keep it from going below."

    The ice packs may cool the water faster than the heater can warm it back up, so you would need to keep an eye on the temperature (and provide good mixing) so you can carefully regulate the addition of ice.

    Best,
    Helen
     
  5. DeanC

    DeanC Member

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    Yeah, you'd want to experiment with how much ice to use to keep the system in balance. Seems like something that you could do over the course of an afternoon while doing stuff around the house. Something like: put one pack in, turn everything on, come back in an hour to check temp. Add a pack, repeat.

    FWIW, this is almost exactly what Jobo recommends.
    Dean
     
  6. Wayne

    Wayne Subscriber

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    argg, damn that fine print....that one you linked to is discontinued (and too expensive). I could spend up to $250 if I have to. The ice cube idea is intriguing but sounds like it could be a hassle. I hate hassles. I'm so spoiled by my aquarium heater, which is absolutely hassle-free for winter work.

    Wayne
     
  7. Lee L

    Lee L Member

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  8. Wayne

    Wayne Subscriber

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    My present tempering bath is a LOT less than 10 gallons (Its an 11x14 tray with just enough water to cover the heater), though I will probably have to make a larger one in order to accomodate an Iceprobe or other chiller. I wonder if it will cool just a few gallons to more than <6 below room temperature. My darkroom probably exceeds 80 in the summer, and its not practical to A/C it.

    Wayne
     
  9. bshaffer

    bshaffer Member

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    In case you also wish to do some homebrew -you might check out willams brewing (there are other suppliers but that one comes to mind) and search for chillers and see if any of the pumps/heat exchangers/chillers might work. if not it might start another hobby -just in time for a global warming summer.
    have fun
    barry
     
  10. Lee L

    Lee L Member

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    The IceProbe doesn't protrude far into the water bath. It needs a 1.25 inch hole to mount through a side wall, with the peltier junction and a fan on the outside. It should be able to cool less water more rapidly. If you poke around on the sites I linked to, you'll see two of the IceProbes cooling a larger volume of (apparently enhanced) water to 20F degrees below ambient in a home-brewing setup.

    Lee
     
  11. jeroldharter

    jeroldharter Member

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    Why not use a Kodak Tray siphon in a 16 x 20 or 20 x 24 tray and a low flow of cold tap water? Unless you are tropical, your cold water temperature should be below 68 degrees.
     
  12. Donald Miller

    Donald Miller Member

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    Try summer temps of 90 on the cold side here. DFW Texas is above 80 on their cold supply from what I have been told.
     
  13. Donald Miller

    Donald Miller Member

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    I have been thinking about this since I will be dealing with the high temps of the domestic water supply this summer.

    I am thinking that an insulated ice chest used to house a supply of ice...maybe even a brine/ice solution with 1/4 inch type K copper coiled at the bottom and brought through the wall of the chest with 1/4 inch bulk head connectors would provide the source of cooling. External of the chest, the tubing would be extended into the tempering bath with a corresponding copper tubing coil in the bottom of the tempering bath. The tempering bath solution would be circulated with a small acqaurium pump amd I would think that this would probably do the job. To control the pump a Thermodisc snap action thermostat clamped on the circulated loop would switch the pump in and out as required.

    No cooling effect would occur until and if the pump were running.
     
  14. waynecrider

    waynecrider Member

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    I mounted a $89 6000 Btu a/c unit in my bath window and it keeps the whole room, and me, around 68 deg if I want it to. Back when I use to develop in tanks with holders I never had a temp problem once I cooled the solutions in the fridge.
     
  15. Wayne

    Wayne Subscriber

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    I think the iceprobe and controller are the ticket for me. Other methods mentioned here will all have some degree of hassle and maintenance for my situation, and the iceprobe (if it works) will be almost hassle -free like my heater is. Hopefully it will chill water in not too much more time than my aquarium heater takes to heat it. My darkroom window is smaller than any a/c unit I've ever seen, or i would consider that, but my darkroom is also HUGE so even if I could get one to fit it would cost a lot to cool-and I'd have to figure out a new exhaust system too.
    Nope, I think the iceprobe is my best bet.

    Wayne
     
  16. Paul Howell

    Paul Howell Member

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    For negative development I use a chilled water bath for developer, stop, fix and clearing, for wash I use a large plastic bucket filled with ice and water with coiled copper tubing running though the bucket from the faucet to the negative washer, wash water is over 90 and is cooled to 70 degrees. A one 8 pound bag of ice lasts for 10 to 15 mints.

    For prints I keep a few cubes of Ice in zip lock bags which I float in the trays, I can keep the trays at 75 degrees without too much trouble.