DIY chiller

My DIY chiller pics

This pic shows the general idea. I small refrigerator with a coil of hose inside with holes for in and out. I used quick disconnects on the ends. The pump in the tank was a RIO 600.


I decided to enhance the cooling ability by putting the coils into a plastic bucket that had rock salt and water in it.
I hooked it all up, had no leaks, the water trickled out just as I had hoped. The slower the flow, the more it would chill running through.
I scrapped the whole project needing a major mod that would make all the difference; after all, none of us are Rockefellers. Instead of the poly tubing, I should have used either stainless steel, or aluminum; as the heat/cold transferrence would have been much more efficient. With the poly, the fridge ran all the time, barley keeping the tank target temp at 78 degrees. I bought a commercial one, that is now giving me problems...shoulda just bought the SS tubing...I still have the fridge...never give up!

 

Only way I ever saw this really work was in a bucket sat in a small chest freezer set at 32F the water in the bucket was frozen but the saltwater in the tubing was not.. I once rewired a dorm box like that e for a guy to try I changed the thermostat to a simple clixon sat at to bring the refrigerator on at 37 F and off at 35F that did O.K but the heat exchange was crap really a chiller is cheaper to run really with the lack of efficiency of the old Polypropylene tubing..

 

The Ice Probe chiller works! Sort of...

I considered the coil in the refrigerator trick discussed above but decided against it because I am interested in salt water more than fresh water. As mentioned above, if the coils are plastic the heat transfer is not really enough, and if metal coils are used with salt water, you are asking for trouble.

There are several good "in-line" chillers that can move salt water and chill it with temperature regulation. These usually cost about $250 or more, but the prices seem to be coming down. Shop around and report it here! These chillers have only plastic in contact with the water and so salt water is fine.

The Coolworks Iceprobe (Ice Probe) 50W chiller cannot move water, but it can chill, tolerate salt, and has no moving parts except for a small fan. It uses thermoelectric technology to turn electricity directly into cooling. The fan and some bulky cooling fins go outside the tank and a 3" by 1" diameter probe goes through a gasket and extends into the tank or filter or sump. If you already have a pump moving water through your filter you could drill a 1.25" hole into it and insert the probe. Others have done this and posted their efforts on other forums. I took a slightly different approach.

I keep tide pool fish and invertebrates in two one-gallon glass jars. Such jars store things like pickles or olives in stores that sell large sizes for about $6. Such jars are 6" diameter and 10" high. Tide pool fish like water between 55 and 70. Salt water reef fish also need summer cooling in Calif.

Coolworks claims one ice probe can chill 10 gallons by 7 degrees and two probes can chill it 11 degrees. This is overly optimistic. Of course it depends on the flow rate of the water and any evaporative cooling that may be going on in addition.

I built a "cooling tower" 3.5" x 3.5" x 10", open on the top. In it I put two Ice Probes and one Danner #02510 65 GPH 707 mini pump. Ice Probes can be had for just over $100 and the mini pump is about $13. One Ice Probe can be regulated by a controller circuit that Coolworks sells for an extra $60, but considering how cold it actually gets, you don't need the controller.

I drilled two holes, each 1.25" in diameter in two sides of the plastic cooling tower (which I made out of a scrap piece of plastic which I glued with acrylic cement). The two Ice Probes enter at right angles, and cross over, one just above the other. On top of these, I put the pump on its side (the intake vents run vertically and the flow control valve is on the top). If you pack everything in efficiently, you can cover it all with about 6" of water in the cooling tower. A plastic nut on the inside presses against a rubber gasket on the outside to make a water-tight seal where the probe enters.

Although the pump runs at 65 gph with no head of water, my set-up is too small for that kind of flow. Therefore, I took the 3/8" i.d. output of the pump and tapered it to 1/8" i.d. This results in about 11 gph flow. The water level in jar 1 is 8.25". It is connected by a 3/8" i.d. siphon to jar 2 which has a water level of 7.25". This is connected by another 3/8" i.d. siphon to the cooling tower which has a water level of 6.25". Thus, the pump is lifting about a 2" head of water which also slows the flow.

Free with each Ice Probe comes a power converter which changes AC to DC and adds some more bulky equipment to deal with. One fringe benefit is that the circulating salt water adds to the oxygen that I get from my little bubbler charcoal filters. Since the water level in jar 1 is about 1 1/2" from the lip of the jar, I had to cut a plastic lid to keep the fish in and let the siphon tubes out. OK, so what are the stats?

air temp = 78, jar water with pump off = 75 (evaporative cooling), jar water with pump on = 70 (five degree cool down). The few cubic inches of water in the cooling tower get down to about 45 degrees with the pump off. This is rather disappointing considering you have to blow $200 to use dual Ice Probes. It is certainly not what Coolworks says in their literature.

Theory says that if the ambient air temperature is higher, the pull-down should be greater. In summer, I would need about 10 degrees. We shall see. Another factor is that I am using cylindrical glass jars. You probably have a rectangular tank. Also, if your tank is acrylic plastic, it will leak cold much slower than glass. Given the water levels quoted above, the surface area of water in contact with my jars is about 348 square inches. This is roughly the same surface area as a rectangular tank 4" x 7" x 12".

Not impressed? Well, you may be better off with one of the everything-in-line combination pump, chiller, controllers mentioned above. However, you will do better than me if your aquarium is plastic or quarter inch glass as opposed to the standard thickness of glass pickle jars ;D.

Have fun and good luck,
Boondocks

 

Improved insulation!

I have a follow-up on my own last post "The Ice Probe chiller works! Sort of..." If you studied the numbers carefully, you probably felt like I did that the Ice Probe should have greater cooling effect on a two-gallon set-up. The problem with pickle jars is that they are very thin. I cannot figure out how to measure one without breaking it, but the walls appear to be less than 1/8" thick. This allows heat to leak in fairly quickly. However, on a hot day I would be willing to insulate the back half of each jar; and in a pinch, I could even go for full insulation.

So I made an insulating layer to cover half a jar using damp paper towels, spray starch, and a little white glue to finish when dry. With both semi-circular insulators in place, I got an extra 4 degrees pull-down. So the total is: 3 degrees with evaporation + 5 degrees with two Ice Probes + 4 degrees with improved insulation = 12 degrees. This is enough for most hot summer days!

No doubt your tank is bigger and thicker than mine. But the trick of using styrofoam or paper towel layers can be easily applied to a tank of any size. Beyond a certain thickness, extra layers of insulation make little difference. I am still not using the controller unit to regulate the temperature.

I am still waiting for someone to recommend a low-wattage low-flow rate commercial chiller that costs less than $300. Has anybody seen or tried one?

-Boondocks

 

12 degrees is nice! Great thread.

I had rather liked my Ice Probe Chiller on my nano, until I had a problem with the coating on the probe. FYI. This actually started happening before I put it away... but became worse after storage.

The only one's I've seen in that price range work under the same principle as the Ice Probe.. I've forgotten the term for that type of electrical chiller... looking it up...Peltier .. thermoelectric.

Seems like you have to pay double what you want to get a good one.

 

Matt Just redip it in a plastic/rubberish coating..I have used it to dip brass probe housings and it works very well.

 

I liked what you said here.
If you've changed your mind, we should follow up on that thread so boondocks cool thread remains intact.

 

Gosh ... This is wicked ... Pretty straightforward idea ... +2 from me !