Water Cooling

[BrianDonegan]

Yeah, I was only joking around. I was thinking of building the whole thing, then using a dummy load resistor as a heat source (so the dissapation is a known quantity), then running the system to see how well it handles different power levels.

Thanks for all the advice!

[E. Pardaans]

I have made a little calculation with estimated temperatures to give you the idea of the needed amount of air.


Environment temperature 35 degrees celcius (worst case).
Estimated temperature of air after passed thrue the radiator 45 degrees celcius.
Heat to dissipate 600 Watt.
Mass of air by 45 degrees 1.11kg/m3.
Mass of air by 35 degrees 1.14kg/m3
Specific heat of air 1000J/kg.K

600/(1000*(45-35))=0.06kg/second.

(0.06/1.11)*3600=195m3/h.


Edwin

[E. Pardaans]

Good luck on your system.

I am verry curious how things will work out as i am working on the same kind of system but without a waterpump.

Edwin

[E. Pardaans]

Hi all,

After the faillure of making a heatsink out of sheets and bars of copper i did make the change to watercooling.
This idea was born after a lot of reading on this forum especially the post from Grey who did this before.

I did make the heatsink from copper tubings with copper bars solderd on them just like Grey did.
The tubes are connected with copper fittings.

The heatsink is big becouse it is designed for natural circulation but i think i will be forced do ditch this idea (not enough space to house the tubes), and go for a pump driven system.

I like to thank you all for your inspiring ideas.

Edwin

[GRollins]

I mounted my copper bars edge-on to facilitate mounting the devices, but if you can tap those for the proper thread without puncturing the tubing you'll have better heat transfer due to more contact area.
Okay, you've got heat staining. Here's what I did: First, go to the hardware store and buy muriatic acid (aka dilute hydrochloric acid). Tell them you want the stuff they use to clean mortar off of bricks. That will take off the oxide and the red/blue stains. The downside is that it leaves the copper dull. The next step is to use 0000 steel wool to burnish the copper back to brightness. Depending on what sort of chemical copper cleaners you have access to, you might try them in place of either or both of these steps. Finally, when you get a nice, shiny glow on your copper, shoot it with a clear finish to keep it clean and untarnished. I used masking tape to keep the mounting surface from getting lacquer on it; I chose to accept a little dulling with age in that one area in order to increase heat transfer, although the thing is so effective I could probably have coated that surface as well.
I took a small, fine file and removed excess solder from the joints so that all you see is copper with a thin ring of silver where the solder is. It's purely cosmetic and labor intensive. You may not want to go to such lengths.
Keep an eye on the relative temperature of your four sets of devices. You've chosen a different layout than I did and you may find that you don't get equal water flow through each leg of the heat exchanger.
A word to the wise. I put my system together with clamps. It works, but it is a pain to disassemble and reassemble. The next time I break the system down, I'll probably install some sort of quick disconnect in order to make things easier. Something like car folks use to do their pressure lines--not garden hose, which will inevitably leak. If you do it now while your system is apart, you'll thank yourself later.
That said, it looks cool.

Grey

[E. Pardaans]

Grey,

I thank you for your advise.

The heatsink is not ready yet.
In order to mount the Fets, i will solder an copper bar on the already mounted bar.
This copper bar will have two thread rods on it so i can clamp the fets (see picture).

Furthermore the heatsink will be provided with a mountingplace for a thermal switch for overtemperature protection in case the natural circulation doesnt start or the pump fails.

The idea of polishing the copper has crossed my mind, and i think it is good looking too.
What kind of lacquer did you use to finish the copper?

About the equal water flow you could be right but ill have to try it in practice to see if it's a problem.

Edwin

[jacco vermeulen]

Originally posted by GRollins
I'll probably install some sort of quick disconnect in order to make things easier.

Braided hydraulic hoses with pressed-on quick release connectors, works great coupling my automatic tranny to its ATF cooler.
Used the same hoses for watercooling the diesel engine in my boat.

Edwin,
there's a company in "de Spaanse Polder" that presses the connectors on the hoses while you wait. Nice picture.

[Nordic]

You can also get awesome chrome connectors from motorbike spares places.. I think it is used in some of the hoses on some bikes...

[quickshift]

It's really easy to make waterblocks.

I made one for my graphics card - just get a soft ally block, shape it to whatever size you need, mill out the channel for the water - make sure it's bigger than the diameter of the tube because the water shouldn't flow through too fast. Tap threads for threaded hose tails into the block, use a sheet of alumunium for the top (bottom) sealed with Sikaflex 921 or similar. Easy Maybe attach a copper sheet to the bottom of the waterblock if you are drawing heat from a small contact area.

I think you would need to use a peltier to enough variation in temperature for a decent flow of coolant - I haven't tried myself so I could be wrong.

Moped radiators are pretty cheap on ebay too

[GRollins]

We're having some really extreme network problems here, so the picture didn't come up--I'm lucky to have gotten the print portion of the page. The network guys are in and working on the problem, so hopefully things will get back to normal soon.
Granted, when I'm shooting a finish on a bass, I pull out the compressor and use a spray gun. Not for this. I just used a can of cheap stuff from the hardware store. A fairly light coat will do.
Now I get to press the "Submit Reply" button and see if this gets through.

Grey