What's new
  • Happy Birthday ICMag! Been 20 years since Gypsy Nirvana created the forum! We are celebrating with a 4/20 Giveaway and by launching a new Patreon tier called "420club". You can read more here.
  • Important notice: ICMag's T.O.U. has been updated. Please review it here. For your convenience, it is also available in the main forum menu, under 'Quick Links"!

DIY reservoir chiller from window air conditioner

gardenbug

Member
First off, go very slowly. Bend carefully. DO NOT CUT OR KINK ANY COPPER LINES. Make long sweeping bends instead of sharp ones.

This is a 5k btu window A/C I turned into a chiller for my dwc setup. It cools a 30 gal setup and a 20 gal setup that each run separate nutrients. It should easily cool a set up much bigger than this.

Remove the case from the unit, usually just a few screws.

You want to use a manual unit, not one with a digital thermostat as it will reset if power is lost.

Remove the thermostat from the unit. It will be a knob with a small copper tube and some wires attached to it.

Place the end of the small copper temperature sensing tube into your container.
Cut and lengthen the wires if needed. DO NOT cut the copper tube.

Separate the cold evaporator coil from the hot condenser coil side. This usually involves some screws and removing some styrofoam.

Carefully bend the copper lines allowing you to place the evaporator side (the side that gets cold and faces inside the house) into your container. I use an ice chest. Fill the container with water.

Leave the condenser coil and fan attached to the unit. Set it somewhere where the heat it puts out wont be a problem, or remove the built in fan and duct the heat outside.

I use 1/2" vinyl tubing and a small fountain pump. Pump from your reservoir through a loop of tubing inside your container and back to the reservoir.
Res -->loop of tube in container-->res.
Your reservoir water never touches the water inside the container. The heat transfer is done from the cold container water through the walls of the tubing.

You can run multiple reservoirs off the same container each with it's own pump and loop of tubing. Vinyl I've found works fine. Copper would be bad due to exposure to the nutrients. Titanium supposedly works fine, but is expensive and not needed for me.

With room temps of 85f I kept my res at 67f easily. The unit ran maybe 5 minutes every 30 minutes. This setup was used over several summers with no problems.

The same thing can be done with a mini fridge but only for very small setups without much of a load on it. The mini fridge cooled my setup but was on constantly and got very hot.
 

Attachments

  • DSCF00081.jpg
    DSCF00081.jpg
    93.5 KB · Views: 13
  • DSCF0017.jpg
    DSCF0017.jpg
    55.6 KB · Views: 14

messn'n'gommin'

ember
Veteran
Pretty slick! Thanks! This is filed away!

Not to be a dick, but you got pic's? You put it in simple enough words I think I can understand, but you got anything for the cognitively impaired and more visual?

lol...Just to be whiney, but would really like to hear your take on how to do a mini-fridge. I don't grow anywhere near as many plants as you and a mini-fridge just might be enough for somebody growing less than, say ten plants.

Good post, thanks!
 

gardenbug

Member
There's a pic of the A/C style and the mini fridge style attached to the post. Not sure if you missed it or if it isn't showing up for some reason.

For the mini fridge just coil the tubing in a bucket full of water and put it in the mini fridge. I would drill the holes for the tubing in the door to avoid hitting refrigerant lines. I killed a few of them drilling in the wrong spot.

I ran the mini fridge on a rdwc setup with 6 plants in 5 gallon buckets and about 1000 watts light. It kept up but never shut off and got real hot. The A/C barely has to run.
With rdwc the pumps, air stones, water lines, all add heat. If you need to cool an ebb/flow setup or something like that the mini fridge might do it.
 

gardenbug

Member
If I remember right it pulls 5-6 amps when running. I tossed out the panel with the ratings on it. I rarely ever get to see it run. It's only a few minutes per hour. Just try looking up the specs for a 5000 btu window unit. I run it on a separate circuit from the lights because it does pull a good bit of power on start up and would dim the lights slightly. Mine is also around 5-10 years old. 5k btu is the smallest you can usually get and up to 16k btu is pretty easy to find. I think 16k btu would chill almost any setup, but the 5k is probably good for most people.
 

avant gardener

Member
Veteran
THANKS FOR THE NICE THREAD!

let me get this straight.
you are using one 5000 btu unit to chill 50 gallons of water,
and you got an 18˚F drop from ambient temperature.
do i understand correctly?
 
awsome now hook that baby up to a pump and a radiator.water cooled air!!!!!!!!!!!!which is the most eficient(spellin).love it peace
 

gardenbug

Member
THANKS FOR THE NICE THREAD!

let me get this straight.
you are using one 5000 btu unit to chill 50 gallons of water,
and you got an 18˚F drop from ambient temperature.
do i understand correctly?


Ambient in the utility room for the condenser coil was around 70-75f. Plant room temps around 75-85f. Water was able to be kept at 67f with no trouble. This was with running around 1k of lights.

I've moved on to coco so it's retired now, but never gave me any problems. Eventually the evaporator coil will rust out from being submerged but that should take several years.
 

gardenbug

Member
Had a couple people mention no pics showing up, if you are logged in they should be there as attachments. I see them, not sure if others do.
 
THANKS FOR THE NICE THREAD!

let me get this straight.
you are using one 5000 btu unit to chill 50 gallons of water,
and you got an 18˚F drop from ambient temperature.
do i understand correctly?

I did the same thing with a 6000 btu. It could pull down 100 gallons of 100 degree water to 55 degrees in a couple of hours. Mine has handled 2k hps in fresca sols and a water cooled co2.

the evaporator lasted 18 months. didn't fail just tainted the water too much.
 

gardenbug

Member
Just wanted to point out again that I had the evaporator sitting in a container of clean water, just some bleach to keep it sterile. If you put the evaporator into the nutrient solution I wouldn't expect it to last long.

Mine began to leave a bit of rust in the water after awhile but that water doesn't touch the plants so it wasn't a problem.

May not be the most efficient way to chill water, but it is cheap to setup and works well.
 
Just wanted to point out again that I had the evaporator sitting in a container of clean water, just some bleach to keep it sterile. If you put the evaporator into the nutrient solution I wouldn't expect it to last long.

Mine began to leave a bit of rust in the water after awhile but that water doesn't touch the plants so it wasn't a problem.

May not be the most efficient way to chill water, but it is cheap to setup and works well.

Nutrient water would leach the copper into the solution and poison your plants. Definately want to do a wort chiller type setup here.

Actually these little chillers are very effecient. I also like the fact that if it fails, I can replace it quite easily and cheaply.

DIY is the way to go.
 
Top