Oil > Copper > Water cooling, need advice!

I am trying to design my liquid cooled PSU, which involves making a stainless steel box, putting the PSU in it and filling it with Luminol TRi and a lot of wire soldering to stop the oil from travelling up the wires, and finally sealing it all up (with valve for expanding oil). The whole thing will be watercooled, and now I am trying to find the best way of looping the copper pipe in there, to maximise extraction of heat and minimize restriction of flow. Space is an issue, and I'd rather it not be super expensive either, although I know I have to fork out a little to get it made.

I am basically unsure how much surface area I'll need in there to ensure the PSU won't overheat under load (probably gonna be a high efficiency (~85%) 1000W PSU pulling 5-600W under load).

I have thought about a slimline radiator, but they are still around 3 cm and I'd like to keep it 2 cm max. That, and I want 100% water leakproof. With a proper copper pipe I'd have to punch a nail through the steel box and pipe to make it leak. I am thinking a 10-12 mm ID copper pipe might be ok.

Any suggestions?

I think you shouldnt mess with the PSU. No reason to cool it other than a big fan. You are just asking for problems.

Oh and PSU have capacitors in them, and they are pretty sensitive to oil...

The oil he is talking about is made for this.

why not mount a copper WB inside the PSU to contact the oil. Run your water throught the loop to remove heat from the oil.

If you use good (430, 304, 316, 318, etc) stainless then why not put the PSU in a box (maybe acrylic or Lexan?), seal the box, and add a couple of barbs on either side? SS conducts heat pretty good (though not as good as copper) but with all that exposed area it shouldn't be a problem. Since the walls of your PSU will be much cooler than the inside area it should create convection currents in the oil. Just make sure your X-sectional area near the barbs is close to the same X-sect area as your tubing - you'll need to "bump out" that area anyway to make the threads.

If your internal heatsinks touch the walls you may want to add some fins in those areas for added cooling. If they don't touch the walls you may want to add an internal connection between them using some left-over stainless or large copper wire ...

samuknow said:

The oil he is talking about is made for this.

why not mount a copper WB inside the PSU to contact the oil. Run your water throught the loop to remove heat from the oil.

Click to expand...

Yep the oil is specifically tailored for this kind of stuff. Otherwise I wouldn't dare.

Do you think a waterblock is enough? I did think about it and it would save some space for sure, but wasn't sure it could adequately remove the heat.

QuietIce said:

If you use good (430, 304, 316, 318, etc) stainless then why not put the PSU in a box (maybe acrylic or Lexan?), seal the box, and add a couple of barbs on either side? SS conducts heat pretty good (though not as good as copper) but with all that exposed area it shouldn't be a problem. Since the walls of your PSU will be much cooler than the inside area it should create convection currents in the oil. Just make sure your X-sectional area near the barbs is close to the same X-sect area as your tubing - you'll need to "bump out" that area anyway to make the threads.

If your internal heatsinks touch the walls you may want to add some fins in those areas for added cooling. If they don't touch the walls you may want to add an internal connection between them using some left-over stainless or large copper wire ...

Click to expand...

Mmm not sure I completely understand what you mean... Do you mean seal up the stainless steel box completely, with the oil inside, and then submerge that in another box with water? You sorta lost me there.

Celoth said:

Mmm not sure I completely understand what you mean... Do you mean seal up the stainless steel box completely, with the oil inside, and then submerge that in another box with water? You sorta lost me there.

Click to expand...

After reading your original post I don't think there'll be enough space for it. You'd said you were going to seal up the oil (even using a valve for the pressure issues) so I just figured a huge, home-made "water block/jacket" using your existing SS sides as a base for it, would work better than running something inside the box.

A plastic jacket (around the 2 unused sides, top, and bottom of the PSU) with metal flanges on the ends should work good. The flanges would be attached to the PSU and stick out past the PSU sides to make up the "sides" of the "water block". Common rubber fan gaskets (or any sheet/strip rubber) should seal the flanges to the PSU. The (1/8" thick) plastic jacket would need to be four slabs cut 1/2" to 3/4" bigger (on opposite edges only) than the sides of the PSU. You'd also need 1/4" metal spacers attached (soldered?) to the PSU to keep the PSU centered inside the jacket. The spacers would also help dissipate heat. Put one flange on, slide the jacket over the PSU, put the other flange on, then use RTV sealant to seal the plastic to the metal flanges. Rubber fan gaskets (or whatever) may also work well here instead of RTV. The only "tricky" part is the plasic bosses you'll need (on opposite sides of the jacket) for the barbs/nipples so you can attach tubing ...