homemade chiller

H

hiepatitis

In Memoriam
I have this small refrigerator that I want to turn into a ghetto chiller. I wanna drill holes in the back and run a titanium coil into the freezer to act as a heat exchanger. The pipe running into the refrigerator will also have a T with a valve on one end to return water to the source and reduce flow into the fridge in case it is too cold. Do you guys think this will work? I've had problems keeping my temperature down in the summer because my parents are too cheap to turn on the AC. Where can I get titanium pipes?
 
Actually I did almost the same thing when I had a sea urchin collecting business and I had to keep them about 45 degrees. I used an office water cooler without the bottle. I used a copper coil (not the best Idea) and I coated it with fiberglass resin. The coil went into the sump in the cooler where there was a small water pump. The device would chill the tank to 40 degrees but the tank was styrofoam. It would work even better with a freeezer but the titanium coil should be in water with antifreeze in it . If you just run it through the freezer it will do nothing. The water against the coil will chill it very efficiently. The antifreeze will allow the water to go to almost zero degrees. If you use plain water in the freezer it will only get to 32 degrees.
Paul
 
Why titanium? Very expensive. Obviously copper or steel can't be used. Aluminum may be, but I don't know the effects of it leaching.

I would try to use a plastic in this application. I would think it would be "cool" to wrap 1/2" pvc or smaller flexible tubing inside the perimiter of the freezer. More size options for plastic rather than the titanium. Its not finding the tubing, but it would be finding the fittings and flaring the tubing to fit them. I don't know if a double faring tool used in brake lines would bend it, or if -AN fittings or hard pipe fitting would seal with the titanium.

However, if you are set on titanium, aircraft/ship salvage would be your best bet. Blue Colar Supply in Sac may have something

You may want to research a "Cool can" made for drag racing applications and check out that design.

If that is all the fridge is used for, then you could adjust the temp of the freezer higher or lower based on your need. Simmilar to your heater operation. However, too slow of a feed could freeze the water, and too fast and not cold enough will not have any effect. So carefull conisderation of pipe diameter, freezer setting, and pump needs to be looked at.

I would aim at a low flow, with as high temp in the freezer as possible to cut down on energy consumption. In addition, filling a freezer, say with ice bags, will make it more efficient also. Planned correctly, the setting would be used to keep the ice frozen, and the ice would cool the water as it runs through.

Definitatly an interesting idea and sounds like a fun project.
 
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Thanks. I would prefer to use metal piping because it has higher thermal conductivity which will make it more efficient but titanium is the only material I know that won't corrode in saltwater.
 
Your right about the thermal conductivity, and metals do have that property over plastics. However, as I mentioned the fittings and forming of the material will be the problem, not the piping. It may not bend uniformaly and require special bender dies to form. In addition if you use pvc or plastic piping, your design is more flexible to what you have to work with, and you are able to add more length of the plastic at a more cost effective rate than buying metals. There are a variety of sizes types as well as fittings to customize your design. You will be able to offset the amount of loss in thermal conductivity with more volume in piping.

For instance, on a camaro I had, I decided to go with steel hardline rather than braided hose or rubber hosing for my fuel pump to carb. The piping was easy, the problem was the fittings, they cost ten times more.

My point is, the real reason for the project was to save money. True, in theory using the best materials will get the job done in the most efficient way, and the easiest. However, engineering is usually about finding a solution that meets certain cost limitations. Most of the time, engineers can not use the "best" material for the job and need to be creative in there design solutions.

McMaster-Carr will have the titanium tubing you need. www.mcmastercarr.com A 60" piece of soft annealed with .250 o.d. will run $200.
 
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I didn't realize how much titanium costs. Maybe I will use pvc with thin walls and let it run through a antifreeze bath to drop the temp like Paul B said or just add salt to lower the freezing temperature of the water. I'm a little worried that the pipes cracking in freezing temperature too. The pipe won't be as elastic so I'll look into it first.
 
I thought that you could run a large line say 3/4 from the tank into the freezer, have it wrap around the outside perimeter of the freezer in a coil, say 3 or 4 times or more, to allow for space to add ice if needed and let her rip, the saltwater won't freeze at that temp, so that won't be a problem. you could get a small powerhead that would be slow enough to allow the saltwater to cool down enough and drop back into a sump preferably. As metioned earlier, you could stock it full of ice to make it more efficient or use the freezer control or a combination of a ball to increase or deacrease the flow to fine tune it. Of course you may have to play with flow rates until you get the cooling you need.
 
I think using the antifreeze would be better than stacking it with ice because the temperature can drop lower and have more contact surface with the pipe. I'm not worried about the saltwater freezing but if I were to use thinner pipes to allow greater heat transfer then I'd have to worry about the pipes becoming more brittle. Since the heat transfered depends on the thickness of the pipe it's kind of a trade off between that and strength. Do you know of any other metals that won't corrode?
 
Sure, but by the time you by it, and form and fasten it, you could have bought a chiller. Look into sacrificial annodes. However, they require electrical current sometimes.
 
The only problem with the annode is that it has to be in the water as well and that means it will corrode and release toxins. Maybe I should just buy a chiller.
 
sorry funman1 for not replying. stainless steel will corrode. galvanized steel is usually used to prevent corrosion of the steel by the addition of zinc. However, the zinc corrodes as opposed to the steel which is still in contact with the water and the steel will eventually corrode too.
 
Yes of course you could buy a chiller but anyone can do that. I don't buy anything that I could build even if it costs me more to build it. Thats part of the hobby. That being said. You can't use galvanized anything in a tank. Zinc is more poisonous than copper. To keep costs down you can use copper in the freezer and convert it to titanium or stainless in the tank. Stainless steel will last long after you and I are dead. It is all over my boat even under the water and has been there for 15 years with no sign of corrosion. I used a stainless steel knife on my reef for a ground probe for many years with no problem.
Plastic is too good an insulator and you would need much too much of it in the tank to make a difference.
Have fun.
Paul
 
Thanks Paul B. I was gonna use titanium because I heard that it was used for ground probes for corrosion resitance but if stainless will do the job then I will try that.
 
Stainless will work (if you can get it) and it will be many times cheaper than titanium which is great if your building a space shuttle.
:lol:
Paul
 
I hate to be a technical killjoy, but when I looked into this years ago I found someone that had done it very simply using vinyl tubing. Just drilled 2 holes in the back of the unit and filled the inside with coils of vinyl tubing. Pretty simple.

I was going to do it, but I'm lazy--- bought a chiller instead.
 
Or just throw frozen bottles into a sump daily, someone else talked about that and had no problem with it.
 
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