DIY Chiller construction

[Dave Vigness]

So, I'm going to make my own chiller. I have about 95% of the parts I need, my biggest question is how to assemble it.

I have a mini fridge, and I have some light sheet aluminum to make a custom tank. I have a guy nearby that can weld aluminum, I barely trust my iron welding, not even going to try aluminum with a laser cutter in the balance. I have the pump and hose, so I'm good that far.

The head scratcher is some of my 'additions'.

I have a small blade style paint mixer like you'd chuck up in a cheap drill. I was thinking of using it to help circulate the tank water a bit like the old pop chillers. Or do I just use a long coil of large copper tube in the tank... say 1/2" or 3/4" so I don't have friction loss. Or I could drop in some baffles between the return and the pump pickup and not bother with the mixer blade or the tubing. ( The baffles are at the top of the list so far for simplicity and no chance of blockage / failure. )

I also have a number of large heat sinks left from scrapping out some other equipment. 10.25" x 1.5" and a little over 1.25" deep. I had an idea of putting them on the outside of the aluminum tank and using some leftover biscuit fans to circulate the cool air over the outside. with or without a shroud of some sort.

Soooo, how crazy am I?

[Tim Mellor]

Not crazy just a little 'special' in the minds of your friends with your tinkering As part of my Laser build I will be going down the path of DIY at least initially as I have some 'stuff' laying around.

The basic guts of it will be an older one of these I paid $50 for and have had in storage due to a change in food prep plans for another part of what I do.



With the Mini fridge is it a compressor one of a peltier type? If it is a Peltier device they are around 10-15% efficient at best so for a 100W one they will only pull 15W out. The waste heat on your Laser will be a lot more than 15W. Compressor style fridges by comparison run 50-60% efficient. For most of us not doing full blown commercial 8 hour runs you can overcome a lack of cooling with a larger tank/reserve sitting cold when you start up and just keep a watch on it.

I wouldn't worry to much about stirring it dropping the return line in above the water level will do a reasonable job then just draw from the bottom (if you are using an external pump). With your Tank as the fridge bieng a closed box heatsinks, pipes etc will largely just be complications you don't need. Increasing the tank size to 75-80% of the fridge volume will be of far greater reserve for more KISS.

[Dave Vigness]

The fridge is a 3.4 cu. ft. with a full compressor. Made to go under the counter. I figured with the aluminum tank made to take advantage of the right size vs a plastic bucket with some wasted space I would be ahead of the game from the start. The rest was one of those 'let's see what I have on hand I can tweak things with.'

Debating on using the one I have in the shop, or swapping with hers under the kitchen counter. Hers has the external rear coils so I don't have to worry about finding them when I put the tubing ports in the side. With mine it appears to have them just under the outside skin, so I'm relegated to poking through from the inside in the plastic, then making the outside metal cuts so I don't hit a line. I won't say how long it's been since I did much more than drop some Freon in a friends AC, and even back then I wasn't the greatest at soldering refrigerant lines. My vacuum pump has long since given up the ghost.

The internal thing was just throwing things against the wall and see what sticks. At the very minimum the return line will be set to encourage circulation. If I had my druthers, I'd love to come across one of the old restaurant premixed pop chillers. You'd have to have worked on one on the early 80's to even know what I'm talking about. They made WONDERFUL pony keg chillers back when I had one. The water pump will be a little submersible for now, but I will be putting in a couple of fittings at the bottom of the tank to give me the external option in the future.

I'll probably under size the tank just enough that I can add the heat sinks on the outside if I need to. Three or four of those sinks on a side with a couple of biscuit fans would increase the heat transfer in my mind. Or should I say hopefully in the tank and not just in my mind.

I have an 80W EFR right now, but I may upgrade to the SPT TR90 tube in the future, and it has a much tighter temp tolerance.

[Willy Ivy]

Here is mine.
viewtopic.php?f=125&t=4435&p=24175&hili ... ler#p24166