Extreme Water-Cooling Using Refrigeration

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Detailed article to adapt a “cube” fridge for watercooling. — Nicholas F. Singh.

Final

The final product – my modified “cube” fridge.

Foreword

A couple months ago, I made my own water-cooling system from a custom-milled copper block and piping, soldered together in my basement. The copper block had 5 holes drilled through it length wise, and the 2 pipes on the side were machined to fit the exact curvature of the block. This design, I felt, would be the most efficient due to the fact that a very high volume of water can be passed through the block at a slightly lower speed than normal – the ideal condition for heat transfer via water.

Block

I placed this block on top of my 1.33 GHz Athlon, 266 MHz, and secured it down with the decidedly crappy clamp I got from Danger Den. Careful – that thing is an outright socket lug killer! I snapped off 3 of my lugs before I got the hang of this dumb thing. Epoxy anyone?

I decided to put my water input/output points where my power supply was originally mounted. I decided to cut out the upper portion of my case, move my power supply up, and design a custom plate to cover the hole left by the supply and hold the barb-hose fittings. The size of my massive “old school” Gateway 2000 case allowed for this.

After measuring, drilling, and threading up a storm, I got two ½” brass male hose-to-barb fittings into the custom plate, which were secured down by two ½” conduit locknuts.

Comp

I then simply ran two reinforced hoses out to a crappy Rubbermaid water reservoir with a fish tank submersible pump. Needless to say, the water got very hot, very fast. I always knew I’d try to upgrade this cooling setup, and Christmas Break was my opportunity to go nuts.

The focus of this article is not on the design of the water block, but rather the method by which I used a small refrigerator to super-cool my system’s circulating water.

Section 1: Selecting the refrigeration unit

Three words: Size, Size, Size.

That’s all that matters when it comes to selecting your refrigerator. The smaller the better, because you will move it around a lot when drilling holes and while testing for water leakage. And also, if you’re like me, you don’t have the much room for a massive fridge next to your computer! In addition, the smaller they are, the less expensive. This is not always the case, though. I suggest getting an older one with dimensions around 19″ cube.

Cube

I got mine on eBay for $20. It had a big dent in it as you can see, but I could care less. Aye, as long as it works! Unless you’re finicky about the cosmetic condition of everything in the vicinity of your PC, and unless you’re loaded with money, don’t bother buying one new – you’ll spend enough on the parts for this cooling design! (New mini-refrigerators can cost upwards of $100)

Section 2: Refrigerator Mods

My design calls for two ½” hoses to circulate water through the unit. I cut two 5/8″ holes in to the left side of the fridge about 4 inches apart. The width between holes isn’t that important, but I suggest you cut from the inside out. As you’ll see in the next picture, the ice cube tray and temperature controls can get in the way of your drill. If your holes are too high, you’re going to have a tough time in the future.

Mod

This drilling will create a bit of a mess due to the foam core, so do this outside or in your basement. Use a rotary tool to clean up the jagged edges of the outer metal casing, or take a round file to it. It will need to be smooth, so do a thorough job of it. And, WEAR SAFETY GOGGLES. You’ll be thanking me when little scraps of metal clank up against your goggles as you drill.
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Nicholas F. Singh

Section 3: Fitting Assembly

Next, I set out to create an assembly that would allow me to screw on two hoses to the outside and have two barb connectors available on the inside. Sounds simple, but you have to remember that there is about ½ inch of insulation to deal with, and you can’t screw on a hose-to-barb fitting directly onto the flimsy outer metal casing!

Whip out your ruler, and measure the distance between your two holes. Then cut two aluminum reinforcement sheets to distribute the pressure of the fitting assembly along the inner and outer edges of the fridge. For this design, you’ll need:

  • Two ½” brass nipples
  • Two 5/8″ brass couplers
  • Two ½” male hose-to-barb fittings
  • Four ½” conduit locknuts
  • One sheet metal plate, with Two ½” threaded holes
  • One sheet metal plate, with Two 5/8″ UN-threaded holes

The parts are pictured below, along with the final fitting assembly:

Parts

DO NOT TIGHTEN EVERYTHING YET!

Only tighten the partially assembled parts you see on the top of the left image (above). Be sure to use Teflon tape thread sealant on all joints, or you will have leaks.

Take the plate with the threaded holes and screw in both nipples. Then tighten on the couplers and the conduit locknuts on the opposite side. Tighten these as much as you can, because you won’t get a second chance without a lot of work!

Now, take this partially assembled half and insert the couplings into your refrigerator holes as seen below. If you’re confident of the fit, you may want to epoxy it to the case, but it shouldn’t be necessary. I do suggest you get some expanding foam to fill in the spaces around the couplers. It’ll cut down on cold air leakage, and will also serve to stabilize and secure your fitting assembly. I used “GREAT STUFF Minimally Expanding Foam.”

Insert

Now, place your other plate up against the holes inside the fridge, and screw in your two barb/locknuts as shown below. Since the holes on this side of the plate are unthreaded and slightly larger then the brass threads on the fitting, the metal plate gets pressed up against the walls of the fridge as you tighten the barb fitting. If you cannot tighten the barb any further and the plate is still not flush against the inner wall, tighten the locknuts to your liking.

Fit

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