TEC Waterblock question

Quick question

Sandwich a TEC between waterblocks... For the hot side, it's almost a no-brainer, just get a (cheap) CPU waterblock: an HK, or Supreme or Apogee.
Since the microfin/pin baseplate design is probably the best to get rid of the watts at the TEC hot side. No need to re-invent the wheel here.

sample




However, i'm not so sure if slapping a similar CPU Waterblock on the cold side is such a good idea.
To me it feels that the microfin/pin design could dramatically increase the chances of icing if you allow the TEC cold side to drop too low (eg idle load)


So, i'm wondering what would be the best "design" for the cold side waterblock base to minimise the freezing chance while still provinding good flow & thermal transfer ("cold" pickup)?

Diamond like the Apogee GT ?



Piramid studs like the old Koolance blocks?


Crosscut like micropins, but with large/normal pins?



Channelled like the old DD Maze?



Just "flat" would work also of course, but it would be also be the "lowest performance" and i'ld like to do somewhat better.


I can ask the metalshop around the corner to mill me a (couple of) full copper custom waterblock(s), but i need to come up with a design for the baseplate. And my head is slightly spinning

(And yes, having them mill "channels" would probably be cheaper as "diamonds")


But... am i not overthinking it all?


Might it not just be easier to buy 8 CPU blocks?
And stop worrying?

How cold are you planning on running the loop?
You'll probably want some form of active control on the TEC, and if you're doing that already you can use it to prevent the cold side block from getting cold enough to ice up.

its all a bit "pie in the sky" in the sense that no clear defined "plan" or agenda -except for "this year"- exists

The goal:
-a chilled loop and/or chillbox (a well sealed chillbox wil avoid condensation issues on blocks/hoses)
-has to deal with +500 Watts (upto maybe 800 W) load (peak)
-TEC Hot side cooling/dissipation: one (or more) MO-RA or NOVA
-a "bank" of 4 or 8 parallel TECs (depends on availability, block design, power requirements, etc)
-all in a custom build cabinet -probably a nice wooden/stainless finish- with a (mini)fridge at the core (will be "slightly" bigger as a normal PC case) 1!
-subzero is NOT a goal
-subambient is definitely on the books (not wanted, but inevitable i fear)

Control: well yeah, i fear that "Krows TEC controller" will be a bit "lacking" for this. So, dont know where to go there...
i had in mind a contraption to be able to manually switch on/off each TEC in the bank individually. Except maybe one TEC where the input can be regulated to allow "for quitely meandering away around ambient" while idle.

And manually flip the switch to ON for the other TECs as required.

Waterflows remain constant; and with large enough reservoirs on the "hot" and the "cold" loops, i should have a large enough thermal buffer to minimise "overshoot".
Imagine 3 or 4 switches: idle, load, game, CrazyOC/Bench

As for power to TECs themselves.. probably 24v ones and feeding them 12v. (i need to look some more at numbers/charts for that and probably ask some more questions also)

Briefly considered going for larger "banks" of 10 TECs or more in series and feeding them mains power, but building a bridge rectifier for that could be a bit of challenge.

Fully automated switching/control (PWM) would be nice, but most commercially available (industrial) controllers that can handle the banks current can't even do that while still going for $1k (at least as far as i know/have found).

So, to finally answer the question, as cold as i can without getting into too much trouble. Subzero would only be for showoff reasons, and i dont need subzero. Subambient is inevitable on the few days when its +30°C at +60 humidity. ...And on the winter days when its freezing outside while i sit comfortably in hawai shirt & shorts in front of my PC with the room thermostat at +25°C


NOTE: dont get fooled by the "fridge",
I'm not using the "PC in a fridge" idea to cool anything, i dont like blown up compressors...
The idea to use a (mini)fridge or (mini)freezer at the core is... because it already IS an insulated box, so i dont have to custom build a double walled case to house MB, CPU, GPU, PSU, et al I only need to build a nice looking cabinet -which houses the MO-RA(s) & PSU(s) & "hot" loop- AROUND the fridge... much easier


PS: While typing this my system draw is 100Watts, but i blame Windows Aero for that.

So what you're after is an insulated box you can toss your whole computer into and cool down below ambient, but not below freezing?

I'd put good money on modifying a small window AC unit being cheaper and more effective, as well as much cheaper to run.

If you want to move 500w of heat effectively you're looking at TECs drawing 750-1000w, and you having to get rid of 1250-1500w of heat.

Bobnova said:

So what you're after is an insulated box you can toss your whole computer into and cool down below ambient, but not below freezing?

Click to expand...

Basically yes... but looking like it actually belongs next to my desk, maybe looking a bit like a filing cabinet

Bobnova said:

I'd put good money on modifying a small window AC unit being cheaper and more effective, as well as much cheaper to run.

Click to expand...

Oh yes, no doubt about that.. except... two things:

1. This country where i currently live in doesn't believe in cheap window/thru-wall units. You either have to go for those horrible 9k BTU things on wheels; or full sing & dance professionally installed split-units. Closest thing i could find to a window unit is some kind of expensive 4k BTU mini split-unit which you hang out the window of your camper/caravan.
While at a snap these things look as if they might work, they basically only have an on/off switch, and if you would put the evap in the "chillbox" it wouldn't be long before it seizes up.. and the condenser end is "quite loud for its size" So much so that you become very unpopular at campsites.

2. they make noise... too much noise


The Mecca of A/C units in all sizes & capacities is Tokyo, a shop on each street corner, no doubt i could find a window/thru-wall variant there, probably exactly what i need.. but shipping could be excessive and trying "hand-luggage" will probably be frowned upon.
Alternative would be some (2nd hand) Wall-mart variant for a kick & a dime, but again .... shipping. Maybe i should try aliexpress "free shipping" from China?

Bobnova said:

If you want to move 500w of heat effectively you're looking at TECs drawing 750-1000w, and you having to get rid of 1250-1500w of heat.

Click to expand...

Yeah, i know... hence MO-RA(s) or NOVA(s) for the hot loop.

At least that i can run that without too much noise

With TECs the power draw would be "above average"; but most likely, by the time the electricy provider catches up to this penthouse drawing as much power as all of the other appartments in the building combined and suspects me of mining, and thus adjusts the monthy bill, i would probably have moved out
Ok, i'm slightly exagerating a bit on the power draw, i'm on the roof of a 7 floor large building, and there are quite few appartments in it

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