Modding Water Cooling Closed Circuit (Waterfall)

Me again

Objective to reuse old modding parts to create something I thought of on the train.

Principle of cheap air conditioning units.

Parts to Hand:
320w TEC (27amps on 12v needed)
500w PSU (33amps on 12v)
3x CPU Water blocks (same make/model)
2x CPU HS
3 water pumps
1/2 inch clear piping
Car Radiator
Lots of barbs and extras
Fish Tank (Only thing to buy)

Basic plan run;
pump 1 > CPU > Top of Waterfall > Bottom of Waterfall > pump 1

HS with fan and cold TEC side > blow air past waterfall > HS with fan and cold TEC side

Hot TEC side > Car Radiator > pump 2 > Hot TEC side


Reason it has three circuits is so I have complete control without the need of TEC controllers or annoying circuitry. Also I wanted to do the waterfall effect with an actual purpose and directly using the TEC without the falls I'm not doing again (destroyed previous PC) has no control over temperature without controllers.

First, just pumps water from the water pooled at the bottom of the tank to CPU and then to top of the fall.

Second, blows cold air from the frozen CPU HS past/through the water going down mesh.

Third, just keeps the hot side of the TEC cool by passing it through the car radiator.


Sister of science has already warned me once the tank reaches max humidity the efficiency shall decrease but not completely. Introduction of the TEC shall keep the water cool even though humidity is to high for evaporation to accure.

Pic of testing TEC;


When the fan runs all the frozen condensation melts.

 

Remember to keep the waterfall section sealed: otherwise the loop will slowly drain due to evaporation. If you wanted to eliminate the TEC entirely, you could make an evaporative cooler, and just keep topping up the loop.
Or you could replace the waterfall with an intercooler (submerge the 'cold' heatsink in the tank directly). That way you're cooling the water directly, rather than cooling the air that cools the water.

 

Has to be sealed as my UPS is very fussy on air conditions.

Which one would produce better result since I was relying on the principle of cheap air conditioning units, I know they use evaporative cooling but thought cold air blowing past would be more effective as there be greater surface area than submerged under water.

Correct me if I'm wrong

 

Isn't this just bong cooling?

 

Not really. Bong (evaporative) cooling won't work if it's sealed. IIRC, anyways.

 

New addition to my modding parts family!

800x400x300mm with lamp ready for cleaning


All important crucial test
Scenario - Just torrenting and go to bed, whilst asleep the TEC gives out and the water slowly gets hotter and hotter up to 65C. Will the tank hold out water tight???

 

Quick back-of-the-napkin calculation:
800mmx400mmx300mm = 96l
Say 60l for 2/3 full.
to heat 60l of water from room temp (25°C, a hot day) to 65°C:
Specific heat capacity of water 4186 J/(kg·K)
60 kg * 40°C * 4186 J/(kg·K) = 10,046,400 J
That's around 3 kilowatt-hours. If your computer us consuming 250 watts while idle/torrenting (a HUGE overestimate) it will take 12 hours to heat the water in your tank after a peltier failure. That assumes the tank is a perfect insulator, the and the peltier never cools the water below ambient.

That sounds like a pretty good safety margin to me.

 

Thanks for the calcs.

Haven't seen maths like that since my sis demonstrated that 2 parallel lines will meet up LOL.

So its safe to say that this amount of water is prob big enough to never get "hot".

Test passed by the way so after cleaning the tank tonight, I get to play with different methods of cooling the water. (submerged TEC direct, air cooling, non submerged TEC direct)

 

Not enough piping, solution; buy garden hose now can have tank on other side of room.

After edzieba calcs I wanted to do a real test, 1/3 full after one night (9 hours) with PC at idle what would the damage be.

Ambient temperature 25C.

Starting:
Tank 21C
PC 19C

Ending:
Tank 25C
PC 25C

What I found this morning, no repeat of history NO EXPLOSION OF WATER


Also went shopping and have finally have more than just a drill!
- 610w jigsaw
- Work Bench
- 6-20mm cone drill bit
- 1-10mm Drill set (0.5 increments)

and a few supplies;
- 2x Alu sheets (0.5x500x1000)
- 2x Alu corner (1x20x20x1000)
- Bathroom sealant (always handy)

Next stage: build waterfall outa the Alu
Stuck on whether to have a fall verticle or it flow down angled alu to reduce noise.

 

@OP:
Just curious, what CPU are you trying to cool with that TEC? Also, is that 320W QMax or just plain 320W? Or are you just chilling the water?

 

CPU is that in my sig E6700 2.6Ghz @ 3.5Ghz, very old CPU.

TEC to be honest I have no idea as was bought years ago in the P4 HT generation but most likely just a standard TEC (50x50mm).

Currently due to time constraints of international travel the CPU is just getting circulated 30 litres of water from the tank with no extra cooling. Plan is to use the TEC to cool the water in the tank via submerged heat sink.

 

Chilling water hasen't worked out that well over the past tries by many over at OCF. You may want to post it here: http://www.overclockers.com/forums/forumdisplay.php?f=71
There's a lot of people there who know a lot more than me about TECs and water cooling, so check it out.

Also check out: http://www.overclockers.com/forums/showthread.php?t=309722

For optimal performance, mount the TEC on the waterblock (will need insulation).

 

Thanks for the links took a while to read through.

Finally back home after Christmas with 3 break downs, 2 spins and one traffic jam in the snow for 8 hours in France. Total time: 14 hours for a 4 hour journey. Lifes good

Currently having doubts on how to finish this project due to above links ?...

 

You can still do it, it's just there is no real point to have the TEC any more. It's proabbly going to end up something like this: http://www.pugetsystems.com/submerged.php
Except it's not entirely submerged.

 

Use TEC because you can, no because it works ^_^

In all fairness if you limit the TEC to a certain voltage that doesn't let it go sub-zero, you should be fine without all that insulating crap, I'd be careful about using it submerged though, as the TEC itself might not be insulated and have problems with water getting in... then you're knackered, as cold air sinks and hot air rises it might be worth putting it atop your res and having a (damn big) heatsink cooling it... or a mosfet block cooling it before it hits your rad and after the CPU (no idea if it'll work, but it's an idea)

 

Be very careful doing this. The issue is not with sub-zero but with dropping below the dew point. Dropping below the dew point causes condensation to form, and unlike freezing, it doesn't happen at a certain temperature, rather a combination of temperatures and relative humidity. If you are going sub-ambient, always insulate.