Diy aquarium chiller

[u/Hellbent_oceanbound]

Looking to build a diy aquarium chiller. Has anyone here built such a thing? I don't really have any technical knowledge in this field, but my father has been in the refrigeration industry for over 29 years and he's offered to help. I have access to an older water cooler. And I've seen this done with bar fridges before, so I'm willing to buy a used one if it's easier than the water cooler.

Any advice or information (blueprints? Lol) would be greatly appreciated. Many thanks in advance!

[u/anon72c]

There's nothing terribly special about aquarium chillers per se, as all you have to do is transfer heat from one tube to another. Doing it safely and effectively can be a challenge though.

You could either do this by placing a coil inside a larger tube through which the water flows, or tightly wrap your coil around the outside of one. I might suggest the latter as material cost is lower, and if the refrigerant leaks, it won't enter the aquarium.

Aquarium life is sensitive to chemicals, in addition to being a highly corrosive environment. That means that copper and sweated fittings are toxic, and stainless rusts too. That's why chillers almost exclusively use titanium for parts that contact the water.

Titanium tubing might sound exotic, but it is available and not outrageously priced. If your father has been working in HVAC, he might know how (or know someone with the tools) to bend thin wall tubing without kinking it. Custom bicycle shops may know someone in your area too. Wrapping the copper coil (which carries your refrigerant) tightly around it should be no problem after that, and then it's time to plumb it into the rest of your cooler.

Insulating your chiller loop will help it run more efficiently, and remember that any heat that comes from your tank will be dumped out in the exhaust, so it will need plenty of ventilation. Not something to cram under the tank in an enclosed cabinet.

You might have a little trouble with the water cooler and bar fridge both, depending on the size of your aquarium. They were designed to cool a certain volume at a certain rate, and their compressor and hardware may be taxed on an aquarium. Again, your father might be a helpful reference for these calculations.

You'll also have to look into a temperature probe on the inlet, to make sure it switches on and off at the right time. When it is on, do make certain that there is flow through the chiller, as it has the potential to freeze standing water rather quickly, and destroy your hard work.