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Thread: DIY? "Cool Coil" Nutrient res chiller

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    DIY? "Cool Coil" Nutrient res chiller

    Anyone looking for a "cool coil" should look into an immersion chiller, or wort chiller. Several models are available in stainless steel or copper for around $50, try google or amazon. Unfortunately our sponsors only resell the cool coil which sells at $112.

    Warning, Do not use copper!! See post #14

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    Re: DIY? "Cool Coil" Nutrient res chiller

    Here is the final product:



    It was made with 20' of 1/4 OD copper tubing, 2 x 1/4OD compression to 3/4 adapters, 2 x 3/4 barb to 3/4 threaded adapters, and a bunch of PTFE tape. Total of $30 at home depot, add some 3/4ID vinyl tubing for $10 and your set.

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    Re: DIY? "Cool Coil" Nutrient res chiller

    I use wort coils for my chiller. Got them online for $45 each, they are 25 foot stainless steel coils.

    I had thought about making my own using copper tubbing. but didn't think putting copper tubing in my reservoir with all the nutes or running nutes through it, was a good ideal.

    I ended up putting the coils in the reservoir, and run plain water through it to the chiller. Makes it much easier to clean between grows.
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    Re: DIY? "Cool Coil" Nutrient res chiller

    Quote Originally Posted by PrairiePoet View Post
    I use wort coils for my chiller. Got them online for $45 each, they are 25 foot stainless steel coils.

    I had thought about making my own using copper tubing. but didn't think putting copper tubing in my reservoir with all the nutes or running nutes through it, was a good ideal.

    I ended up putting the coils in the reservoir, and run plain water through it to the chiller. Makes it much easier to clean between grows.
    Yea this is what inspired me to make my own, about half the price of ordering. I am a chemical engineer so I took the lowest possible pH of my res (3.9) and calculated the dissolved Cu levels. Then I compared that to DM Zone, which uses copper ions to control algae and bacteria in the res and the numbers from the copper were lower by about a factor of 50. So on that evidence I decided the copper was OK. Also I believe that it will for a layer of oxide that will prevent further dissolution.

    I plan to use propylene glycol, just about 1 gallon in 50 to lube my pump and to keep shit from growing in my coolant. If it does pop a leak the propylene glycol is non toxic. They spray it on red meat in the supermarket to keep it from turning brown, it is also in fat free ice cream.

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    Re: DIY? "Cool Coil" Nutrient res chiller

    Quote Originally Posted by Maer View Post
    I am a chemical engineer.....
    Ahhhh! You have the education to understand and do the proper calculations, to fully know. I'm a electrical / computer engineer, and too lazy to go figure it out the chemical sides. Now if I need more tub chillers, I'll feel confident to use copper.

    One thing I might suggest is to increase the amount of coils. The more surface area in the reservoir will make it more efficient in energy transfer. Try to get as much as 20 feet in the coil.

    Quote Originally Posted by Maer View Post
    I plan to use propylene glycol, just about 1 gallon in 50 to lube my pump and to keep shit from growing in my coolant. If it does pop a leak the propylene glycol is non toxic. They spray it on red meat in the supermarket to keep it from turning brown, it is also in fat free ice cream.
    Another great ideal.

    That is one of the great things here on 420, a wide variety of folks to converse with.
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    Re: DIY? "Cool Coil" Nutrient res chiller

    I dunno about that one. Seems like copper leaching with the mineral salts could be an issue. I have read at least 2 stories of tainted gardens due to the copper toxicity.

    You're the engineer though. I would be interested to know if this is a myth, and if we can bust it. Sure would lower the price of chillers!

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    Re: DIY? "Cool Coil" Nutrient res chiller

    Quote Originally Posted by budlydoright View Post
    I dunno about that one. Seems like copper leaching with the mineral salts could be an issue. I have read at least 2 stories of tainted gardens due to the copper toxicity.

    You're the engineer though. I would be interested to know if this is a myth, and if we can bust it. Sure would lower the price of chillers!
    From the same thing? A coil in the res? Did you run into problems feeding DH water to the plants? I would think that has a high Cu / Zn / Fe content. Steve said that CuSO4 is in DM zone, and in the extremely low ppm it will be present in the res it is less than in DM zone.

    I can run a simple test to see if there are any Cu ions in the water, I will after a couple of days and we shall see.

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    Re: DIY? "Cool Coil" Nutrient res chiller

    It's not the copper itself, it's the copper reacting to the salts in a nute solution. So the water coming from my DH is pure, but the water is a rez, with all the goodies we add has much more conductivity. again, I'm no expert but I have seen this discussion many times.

    Would be great to put it to rest with some real data. I would love to be able to chill a rez with my copper coiled chiller.

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    Re: DIY? "Cool Coil" Nutrient res chiller

    I'm trying to sort out the words and what they refer to:
    "chiller, cool coil..etc". which is for air-cooling and which is for temp control of the nutes?

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    Re: DIY? "Cool Coil" Nutrient res chiller

    Quote Originally Posted by budlydoright View Post
    It's not the copper itself, it's the copper reacting to the salts in a nute solution. So the water coming from my DH is pure, but the water is a rez, with all the goodies we add has much more conductivity. again, I'm no expert but I have seen this discussion many times.

    Would be great to put it to rest with some real data. I would love to be able to chill a rez with my copper coiled chiller.
    Why put the copper coil into the res? You could hang the coil on the res so it is 1/2" away from the res wall, and put the whole res with coil into a larger tub. If there is air space between the inner tub and the outer tub, the coil will chill the inner tub.

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    Re: DIY? "Cool Coil" Nutrient res chiller

    I'm trying to sort out the words and what they refer to:
    "chiller, cool coil..etc". which is for air-cooling and which is for temp control of the nutes?
    I found one of those small refrigerators you might find in an office where people put their sodas and stuff and I know I can work with it.
    Even though I would like to create a closed/no exhaust room, rigging up and refilling co2 cant fit in my budget. I have to exhaust. hrrmmm...
    I guess I could put the heat exchanger at the room's air inlet.

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    Re: DIY? "Cool Coil" Nutrient res chiller

    Quote Originally Posted by purzurples View Post
    I'm trying to sort out the words and what they refer to:
    "chiller, cool coil..etc". which is for air-cooling and which is for temp control of the nutes?
    I found one of those small refrigerators you might find in an office where people put their sodas and stuff and I know I can work with it.
    Even though I would like to create a closed/no exhaust room, rigging up and refilling co2 cant fit in my budget. I have to exhaust. hrrmmm...
    I guess I could put the heat exchanger at the room's air inlet.
    Take a look at budlydorights 3000w thread i think it is he puts a windows AC right thru the wall of his grow area. That is great if you have a huge space for the air to diffuse into or you can pipe it outside. Water chillers are said to be more efficient per btu than A/C, almost double..

    So to answer your question directly this thread is for the cool coil which chills the reservoir, the scheme you described would be very inefficient thermally.

    The thread for water chilled A/C is the DIY Icebox thread in my sig.

    The chiller essentially powers the whole system by taking heat out of the coolant fluid. So it "powers" the cloner chiller, grow room A/C and nute res chiller.

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    Re: DIY? "Cool Coil" Nutrient res chiller

    Good thread! Can't wait for the summary.

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    Re: DIY? "Cool Coil" Nutrient res chiller

    So here is the chemical reason this experiment was not successful.

    For those of you that don't know as budlydoright predicted I got a bad case of Iron lockout due to excess copper ions.

    The nutes don't swap directly with the copper, but I happen to use Citric Acid as a pH down, and that will react with copper oxide. So the citric acid keeps the copper free of oxide, the oxygen reacts with the metallic copper at the surface and oxidizes it readily.. so the cycle continues until there is no more citric acid to consume. Most pH downs will do this, some stronger acids will dissolve copper directly. This also has the side effect of neutralizing all the pH down I added, leading to pH problems.

    I will message the admins to edit my first message with a warning not to use copper.

    That said a stainless steel wort chiller is only $45 online, less than half the price of the cool coil product.

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    Re: DIY? "Cool Coil" Nutrient res chiller

    Quote Originally Posted by Maer View Post
    So here is the chemical reason this experiment was not successful.

    For those of you that don't know as budlydoright predicted I got a bad case of Iron lockout due to excess copper ions.

    The nutes don't swap directly with the copper, but I happen to use Citric Acid as a pH down, and that will react with copper oxide. So the citric acid keeps the copper free of oxide, the oxygen reacts with the metallic copper at the surface and oxidizes it readily.. so the cycle continues until there is no more citric acid to consume. Most pH downs will do this, some stronger acids will dissolve copper directly. This also has the side effect of neutralizing all the pH down I added, leading to pH problems.

    I will message the admins to edit my first message with a warning not to use copper.

    That said a stainless steel wort chiller is only $45 online, less than half the price of the cool coil product.
    -- Prairie

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    If you are asking for help, click here to get better answers.

    My only journal:
    Prairie's Trying Again SCROG Deep Water Culture

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