How do these components look for chiller?

Hi all. I will be setting up my chiller system over the next couple weeks and wanted to get some input. The chiller was built by i_jester, and ran an alcohol mixture at -27C (liquid temp).

Pump: Iwaki MD-20RZT
Tubing: Tygon chemical tubing rated to ~ -77C
Block: Swiftech MCW6002
Liquid: Wiper Fluid / Water (ratio to be determined)

Any obvious gaffes? And any suggestions on coolant ratios and or mixtures? I am obviously looking for the lowest possible load temperatures.

How thick do you think my insulation on the motherboard should be? Would 1/2 inch suffice?

Finally, would there be any reason to use an Ultra-D instead of an Expert?

Thanks in advance for your help!

Everything looks well in place to me. The 6002 is an excellent choice for chilling as well, since its very easy to insulate. Pure red windshield wiper fluid is the most cost effective coolant solution I've found. However, past -30C you should start adding alcohol.

Gautam said:

Everything looks well in place to me. The 6002 is an excellent choice for chilling as well, since its very easy to insulate. Pure red windshield wiper fluid is the most cost effective coolant solution I've found. However, past -30C you should start adding alcohol.

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Thanks for the feedback mate. I had one concern about pure wiper fluid. I couldn't find any info on its specific heat (or some equivalent measure). I guess my concern is, what good is it if it can cool down to absolute zero, but immediately wilts under load. That is to say, it needs to be able to hold those temps as well. That's why I was thinking it would be good to have as much water in there as possible. Any thoughts on this?

Water's specific heat is 4.18 J/(g*C), methanol (what ww fluid is) has specific heat 2.55 J/(g*C). Not enough of a difference to matter for our application. Sure water is superior technically, but methanol definitely won't "wilt" under load. I use a mix of ethyl alcohol and methanol, both around 2.5 J/(g*C), and my water temperature doesn't budge any more than half a degree under load, tops.

You don't want to add any water in the loop. It'll freeze very fast under the sorts of temps you'll have. That's a far, far bigger concern here than specific heat.

Quite right you are. Great info - especially regarding the idle/load temps. That alleviated my (naive) concerns. Gimme a week or so to get everything together and I'll post some results. Thanks again mate.

Np, I'll be looking forward to em. Looks like you've got a quite a quick array of procs as it is.

Gautam said:

Np, I'll be looking forward to em. Looks like you've got a quite a quick array of procs as it is.

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Word, pls post pics