NANFA-L-- Homemade chiller

Jase Roberts (
Mon, 29 May 2006 12:59:11 -0400

Hey All,

One thing to consider with Todd's fan chiller (swamp cooler, essentially) is that box fans use a LOT of electricity. My standard one from Wal-Mart or whatever draws 120W on low, 160W on medium, and 220W on high... That adds up quickly (especially if you're running two) And, of course, remember that all of that electricity is ultimately being converted to heat (in one form or another). As Todd notes, it's only going to work if your humidity isn't too high, and you're going to need to add quite a bit of water to the tank as it evaporates.

Here's a thought I've been mulling over for a cheap chiller... I haven't built this, but I can't see why it wouldn't work. I plan to do this whenever I decide to actually start breeding my natives.

Use either a little bar fridge OR your regular kitchen fridge (depending on proximity of your kitchen to your aquaria and the sensitivities of your significant other). If you can get by with your kitchen fridge, you'll save all the extra cost of running a second fridge (those little ones are usually pretty inefficient, since they're marketed to college kids and cost of the initial purchase is the driving factor -- certainly not energy efficiency).

- Drill two holes through the side/back of the fridge to accommodate 1/4" ID vinyl tubing (or whatever diameter you want/need/have on hand). Don't hit the coils or any wires (unplug your fridge first, please)
- Get enough vinyl tubing to reach from your aquarium to the fridge and back.
- Cut the vinyl in half and pass it through each of the holes in the fridge (so you have two free ends inside). Use silicone or hot glue to seal.
- Get/make the appropriate fittings to connect a few feet of flexible copper tubing to the vinyl inside the fridge, and wind that into a coil.
- Inside the fridge, have the copper tubing sitting in a 9x13 baking pan (or whatever) full of water (better heat transfer). The copper tubing isn't open to this pan, just passing through it.
- Get a cheap in-line pump ( or submersible pump ( and connect that to the vinyl as a feed from your aquarium. A consideration here is that the pump is going to ADD heat to the system, so in-line is probably better and as small as possible definitely best.
- The free end (coming out of the fridge) then just returns to your aquarium.
- Control temperature by turning the fridge up or down, OR by adjusting flow on the pump (if it's variable)

So the whole thing (drawn linearly) looks like:

aquarium -----> vinyl tube ----- inline pump---- vinyl tube ----->(next line)

---------FRIDGE--->[____copper tube in water pan___]---vinyl tube---(next line)

----------> aquarium -----> cool, happy fish

Any reason this wouldn't work? The bigger the surface area of the water pan in the fridge (and the longer the copper tube heat sink), the colder the water you're going to be able to return to your aquarium.

If you really want to take best advantage of it, get some rigid Styrofoam insulation to line the back and sides of your aquarium with (reduce condensation and heat loss).

If you try it, let me know. I'm curious.

Montpelier, VT

Crail, Todd wrote:
>>Has anyone tried modifying a personal (tabletop) refrigerator as an
>>inexpensive alternative to a chiller?
> As for a chiller... Here's one that I put together last night with this
> freakin' hot spell we're under (It's too early for this crap! Sheesh!)
> One is blowing down, the other is blowing out. Lost the temp on the temp
> gaugae last night (which meant it was in excess of 86 F). It's down to 76
> right now. Also lost about 3 gallons of water lol. Gas exchange can get you
> out of a bind in a hurry :) You can do the same on smaller systems with a
> little clip on fan. The only time you get into trouble is when it's dagnasty
> humid and you can't get a single drop more into the air. However, by doing
> this in combination with AC, you'll make the AC run a lot more efficiently at
> cooling the tanks.
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