DIY Chillers

Discussion in 'Anything DIY Related' started by Dragonet, 20 Oct 2009.

  1. Dragonet

    Dragonet

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    Hi all

    I know there has been a lot said about a Bar fridge not being able to cool a tank down sufficiently, so I was thinking about using a small chest freezer.

    Most chest freezers have a complete plastic housing inside (so no joins) if I was to coil up say 100m of 10mm ID tubing and then fill the bottom of the freezer with water and place the tubing into the water with air inside the tubing and then allow the water to freeze then couple a 200L/H pump onto the tubing and pass the tank water through the tubing into the freezer which is embedded into the frozen ice and then back into the tank, do you think that this would work.

    Is there anyone out there that could work out the BTU rating of a 220L chest freezer and whether it would have the power to cool down the tank without overloading the freezer.

    Has anyone else tried this??

    I ask because as you know a chiller for a 400L tank will cost around R3,500 and a 220L chest freezer will only cost around R1,800 that is if both are new.
     
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  3. Pugsly

    Pugsly

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    I have seen a guy use the standard bar type fridge and it worked like a charm. If I can recall, he had a 700l system. What he did was use both the freezer compartment and the fridge compartment.

    Namely the inlet side if the piping came into the freezer section first to cool a bit quicker and then into the fridge compartment. For him it worked like a charm! He too only ran around 400lph through it from the sump and back into the sump. His system ran at 25 all the time.

    I know he used a timer setup somehow that when the lights went off the fridge would turn off around 2 hours later and then turn on again and hour prior to lights turning on.

    I think the timer was used because the thermostat on the fridge was faulty (was a old fridge he used)
     
  4. lIghty

    lIghty

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    A DIY chiller can be built, just remember you can't use any copper in the heat exchanger!

    I know Brett2020 built one.
     
  5. durleo

    durleo

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    I would try to get a secondhand chiller if finance is the problem. A chiller will only work when the water needs to be cooled and will not waste electricity. You will have to constantly tweak a freezer to get the water temp stable.
    Jus A thought;) Look around on the forums and you might pickup a good deal
     
  6. Renannchen

    Renannchen

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    I can get the same tipe of setup as a chiller, also diy, a guy here in bloem made 1 for his 1000l setup and it workd like magic. He builds everything diy and im also thinking of getting a diy chiller.
     
  7. brettb2020

    brettb2020

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    iv crunched some numbers for you guys, im busy doing refrigeration at varsity at the moment. so its till fresh in the brain:)

    using that fridge diy chiller setup is only about 20% efficient!!!

    a 220l chest freezer has a 1/6 horsepower compressor which is capable of about 1600btu. which could chill about 500l if designed properly at an efficiency of 90%. but with a fridge you loosing 80% of that. so you gonna be paying alot on electricity for nothing.

    the main reason is that a proper chiller directly chills the water where the fridge setup first chills the air and then the air has to chill the copper which then chills water. air really sucks at transferring heat, you need large surface areas for it to be efficient. a copper pipe has almost no surface area for the volume of water in it.

    its much better to just buy a chiller. save you alot time, hassle and money in the long run.
     
  8. RiaanP

    RiaanP Moderator

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    I know this is about chillers, but also about cooling the water. I found an big open scrubber with a fan on it to be very effective in cooling the tank. So much that my heaters runs daytime in February. Top-up becomes an issue then. Fan on same circuit as the lights. A lot cheaper than a chiller and it does two jobs in one.
     
  9. Stressed Eric

    Stressed Eric

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    One thing you need to watch out for if using the freezer idea for chilling, when your tank is at the right temperature, I assume you'll cut flow to this line . . . The water will freeze in the pipes, won't it ?
     
  10. jean19

    jean19

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    stressed eric make a point there .
     
  11. butcherman

    butcherman Moderator MASA Contributor

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    at what temp dose salt water freeze i think it's a little lower that fresh water not 100% sure but i think its definatly somewhere below 0 celcius
     
  12. mnd123

    mnd123

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    Salt water does not freeze at the same temperature at fresh water which freezes at 0 degrees C (32F) and depending on your SG, will freeze at between -2C and -20C.

    But yeah, in a deep freeze it will freeze eventually if its not moving fast enough :)
     
  13. mnd123

    mnd123

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    Standard sea water which is 3500ppm salt will freeze at -2C
     
  14. butcherman

    butcherman Moderator MASA Contributor

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    cool very interesting. :)
     
  15. RiaanP

    RiaanP Moderator

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    What will happen if you have a big tub of water in the fridge. And the flexible pipe runs like a coil in the tub or bucket. So the Fridge cool the water, the water cools the pipe. That should be a lot more effective than the fridge trying to cool the pipe.
     
  16. durleo

    durleo

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    Basically a fridge or freezer is a heat exchange and there is energy lost between the heat exchange from the pipe to water to air to compressor. The chain for heat to leave is longer and thus less energy efficient. Your electricity bill over time will show for it.
    We try to take shortcuts but eventually shoot ourselves in the foot.
    I looked at all options and eventually settled on a 1hp Hailea Chiller that was a bargain at R6500 and it was brand new. It chills my 6ft tank with no hassles.
    If you gonna invest in a chiller rather go a little bigger so that it isnt running all the time and when you decide to go for a bigger tank you wont have to change it.
     
  17. Dragonet

    Dragonet Thread Starter

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    So then by all the comments to this DIY Chiller I can take it that this just isn't a viable option and that one should just bite the bullet and buy a proper aquarium chiller.

    This then leads to me to my next question, Does anyone have a second hand chiller that they are no longer using or would like to get rid of as a new chiller is just going to break my bank.

    My tank is around 400L.:whistling:
     
  18. dendrosa

    dendrosa Member

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    Dragonet, I'm not so sure that anyone has answered your question directly here. Most people seem to gave commented based on the heading rather than how you want to set this up. If you could get hold of an old, cheap 2nd hand chest freezer to give this a try, I'd say it would be worth having a go. The advantage is that you don't have to destroy / damage the freezer in any way while experimenting. It may not be as efficient as a full on chiller, and cost a bit more to run, but if it can get your tank through the summer while you save up for a chiller, it may just be the way to go.
    If you do try this route it would be interesting to hear your results. May just help other cash strapped reefers get through a hot summer
     
  19. durleo

    durleo

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    Hey there

    Get in contact with Marco - Waterboy - HE is a sponser and he gives great service.
     
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