Senior Project Design (active submersion / Internal cooling device)

two quick questions

Anyone know an easy way to estimate the BTUs produced by a certain computer?

Since you have discussed this alot even before i decided to try it, what kind of liquid would be best?
 
ShinySwords said:
two quick questions

Anyone know an easy way to estimate the BTUs produced by a certain computer?

Since you have discussed this alot even before i decided to try it, what kind of liquid would be best?
Click to expand...
use the wattage ratings of your key components, or better yet, work out the power draw from the wall with an amp meter and the PSU's efficiency, and then crack out your handy scientific calculator with unit conversions, and off you go. the conversion factors should be in any good thermo, engineering or physics text, if your calc can't do it for you.

acetone is great stuff, because it has about the viscosity of water even down to low temperatures. using it means that you need to seal the container reasonably well. mineral oil is non-conductive, and has reasonable heat transfer properties, however its viscosity varies more depending on temperature and formulation.
 
acetone would be a nice idea, alcohol's are the best for these situations, people with chilled water run stuff like denatured alcohol instead of water because water would freeze only possible issue is make sure you have everything dunked including maybe psu before you plug it in, you certainly dont want a spark :eek:

for wattage to dissipate, measure power consumption and treat that as the heat generated, with a air conditioner i bet your still gonna be sub 0 even with cooling the psu with it, and hey, super cooling your psus only gonna make it work better :D that is unless you intend to break the prescott speed record, any other cpu and you would be fine, man my prescott was hot stuff... calculated thermal output to be at about 160 watts(power consumption so high i burned out my max3's voltage regulator) now i have no gaming system :( ohwell taking the chance to build myself a dothan system
 
For the liquid im looking more for a flourocarbon equal, acetone would be too dangerous i think (just too volitile), im looking for a specialty liquid to submerge it in, non corrosive, non conducting, has a good heat transfer, can withstand big temp drops, nonflamable, doesnt react or damage the main parts of a motherboard (and all thats attached)

I know theres something better and by brother owns a business so i might be able to get controlled substances for a discount haha

Acetone would eat through everything haha, ive seen it since ive used it to remove paint and such from a car
 
ShinySwords said:
For the liquid im looking more for a flourocarbon equal, acetone would be too dangerous i think (just too volitile), im looking for a specialty liquid to submerge it in, non corrosive, non conducting, has a good heat transfer, can withstand big temp drops, nonflamable, doesnt react or damage the main parts of a motherboard (and all thats attached)

I know theres something better and by brother owns a business so i might be able to get controlled substances for a discount haha

Acetone would eat through everything haha, ive seen it since ive used it to remove paint and such from a car
Click to expand...
Yeah I think that might have been a joke about the acetone. Acetone is what is in nail polish remover. Umm yeah....

Have you looked at documenation from old supercomputer projects? IIRC some of the Crays and other big boys used immersion cooling systems.
 
Just for reference:
X2 3800+ 1.71-1.73v v-core running 3ghz dual priming with 2x1gb ballistix around 270mhz, 7800gtx overclocked, DVD, 2 HDD, etc do eat up about 350Watt from outlet. Considering efficiency of PSU, it probably is using about 260-280 watt amongst components. Out of this, about 150-160watt is purely cpu while rest is GPU, hdd, memory, etc, etc.
If it is tuned for 300 Watt (about 1200 btu/h I think) I think with some good 1/3hp compressor ones you should be able to see evaporator temperature (in this case coil that gets dunked inside cooler) below -25c. You might not get this cold evap with off the shelf air conditioning unit with even more BTU rating as it wasn't tuned for that temp (they were designed with above 0c in mind after all they usually were designed with more capacity in mind than cold temperature). Now that -25c might not translate to your oil temp for obvious reason (does your temp of water equal radiator air outlet temp? Obviously not.
What you need to find is oil that can really transmit heat well. Figure out best way to direct the flow of oil, and how to maximize heat transfer from oil to evaporator so that you get best temp over all to your components.
 
jinu117 said:
You might not get this cold evap with off the shelf air conditioning unit with even more BTU rating as it wasn't tuned for that temp (they were designed with above 0c in mind after all they usually were designed with more capacity in mind than cold temperature).
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This is just fine, if i could operate around 0c, it would be plenty good enough for what im goin for with my funds and goal.

What would you suggest for a liquid to use that has a really high and really low temp range while also being able to transfer heat quickly?

Lastly, anyone have a web page or such that they found that kinda demonstates the formulas for the heat, or better yet, that links it to the heat produced by a computer?
 
ShinySwords said:
This is just fine, if i could operate around 0c, it would be plenty good enough for what im goin for with my funds and goal.

What would you suggest for a liquid to use that has a really high and really low temp range while also being able to transfer heat quickly?

Lastly, anyone have a web page or such that they found that kinda demonstates the formulas for the heat, or better yet, that links it to the heat produced by a computer?
Click to expand...
You're making me repeat myself:

Technical Mumbo Jumbo
 
OK so im ganna either order an ac unit off the net or buy one from walmart. If anyone has an idea of a good one from ebay, or just online, please post it here. Im hoping for an efficent, smaller, easier to mod one, but give me some idea if you want. If i get one from walmart it will just be a cheaper one, but if you guys want some input in this then tell me what you would suggest.

The next step in my project is to order an AC unit so that i can figure out demensions for either a custom made case or a modefied fish tank, lol. I need to do this so that the rest of the project can be planned accordingly.

Also, once i get this info and specs, one thing i want to take into consideration is the fact that I want to over clock the processor and or the video card ( 2600+ amd, geforce 5600 256mb) in order to demonstate one of the advantages and kinda impress my professors. Can i over clock the Processor and or video card whithout damaging the motherboard. Basically, im ganna probally buy a few processors (since there cheap) and or a few video cards so that i can play around and lastly demonstarte the over clocking in the final presentation. If i can over clock and not damage the mother board it will be easier but i need to know if i can fry a chip and or a video card without damaging the mother board for demonstation purposes.
 
ok havent posted in a while but still workin on it. Im ganna go with a fishtank with a custome made chiller in the bottom of it, then a hollowed top to put the moving parts in. The top will have the submerged parts fascined to the bottom of it so i can pull the motherboard and submerged parts out just by taking the top off in a sense.

what fluid is suggested by this forum that wouldnt cost a fortune but has a nice temp range (also, would some of the liquids be too heavy for a fishtank?)

If the moving parts (hard drives, cd rom, etc) are not submerged but close to the submerged liquid that is very cold (seperated and sealed from the liquid), would they be ok since they might be running at a lower temp that the normal room temp?
 
Law of conservation of energy remains. Too keep liquid cooler, it would be better to keep only essential parts in the chamber with liquid (mobo, video, etc)
The rest should have different path with some aircooling (if that). Only thing I would worry about in temp would be HDD and even passive cooling works good on HDD to be honest.
Maybe you can think of dividing the tank up where some parts have airflow through it while the other parts are totally insulated and submerged.
In related note to forum members:
#1. liquid that can handle -25c or so while acceptable for submerging.
#2. Pump recommendation for such liquid slugging around at above mentioned temperature.
Do you guys have any pointers?
 
Whatever you go with you should put a big [H] on the side of the "case". After all, I think we have done most of the work for you now. :p
 
ryuji said:
vegtable oil's prob fine, unless you intend to go past -20C
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That is the iffy part. Get the feeling it might just go tad below that with properly insulated system and especially when system is under idle. Maybe it won't go that low under loaded condition but it is possibility nevertheless.
 
Anyone have any good ideas for a pump for high viscosities at low temp. Would just like a norm pond type pump be good enough?
 
Swords,

Well, I wasn't going to post any of my new findings until the new project was finished, but this is for your education, so here it goes.

First off, a fishtank isn't going to work very well. You'll get some cooling, but the condensation off the glass sucks, and the heat loss is immense. Here's why:

100_0166.jpg


This was the first iteration of an active cooling submersion project I've been working on for the last year. You'll find according to the fluid discussion thread (http://www.hardforum.com/showthread.php?t=851060) that I was working with a new submersion fluid called Luminol TR-i. Not much was known about the product for a while, but thanks to the work of BrainEater and myself, we now know a great deal about it. I've been working with a system submerged in it for about a year now. I really think that for your project, you should be contacting the company mentioned in the fluids discussion thread. It's cheap, and works very well up to about -20 Celcius. Anyway, here are my findings:

The fishtank worked OK, but would only cool the fluid to a few degrees above freezing. The picture above shows some of the 'worst case' testing I was doing. The air conditioning unit is located behind the motherboard. It was an 8000 BTU unit using R22. I would start the motherboard up, fire up the A/C, and measure the time it would take to lower temperatures over a time period while the system was generating heat. Generally, the best way to get low temps was to fire up the A/C for 20 minutes, then start the system. However, all things will always come to a thermal equalibrium, which I found to be at about 15 degrees Celcius. This was with a 1.0Ghz T-bird cranked up to 1.5Ghz. System ran fine at a 50% overclock, and would have gone further if my motherboard hadn't limited it. The pump I was running was an Eheim. Luminol gets a little thicker around freezing, but it's nothing the pump can't handle. You'll notice in this pic, I wasn't even running a water block on the CPU yet, just having the pump shoot the Luminol over an old Aluminum heat sink. The pump was drawing fluid from the back side of the evaporator.

So, with all these findings and a few weeks of thermal tests under my belt, I designed another system. This time, I used a cooler (5 gallon cooler, like the ones you find at Wal-Mart they are very well insulated), and some Neoprene fittings. I drilled two holes in the top of the cooler, underneath the cover, and ran all the electrical and A/C lines through it, surrounded with Neoprene. (I don't have picutres of this yet, I was waiting for my next interation) This created a near air-tight seal for the system to function in. This becomes important later, as Luminol is reactive to U/V and Oxygen, and the new system protects it from both. This allowed me to get coolant temps in the -10 Celcius range, at which point my 20 year old A/C compressor took a crap on me.

So, I'm in the process of designing system number three. System three is using a 5200 Haier A/C (with analog controls, which you will find very helpful in your design), and an Athlon 4000+. I'm going all out on this, so this should help you a bit. I also found that if you combine a Peltier into this mix, you can easily attain -40 degrees celcius on your CPU without affecting any of your motherboard components. Capacitors and the like don't really like going below -20 degrees celcius. This new design allows you to get the best of all worlds. You can cool every component on your system to -20, and cool your CPU to -40. The only drawbacks to a system like this are the weight and power consumption. However, if you work hard, you can cut these down to managable levels. Working two ATX power supplies into the system seems to be the way to go. One for the Peltier system (not the most efficent way to go, but cheap and it can work when paired with the right Pelt), and one for the rest of the box. Keep all your drives and power supplies away from the immersed fluid. Power supply components do not like to be kept at -20 Celcius for long periods of time.

For the sake of not writing any more of a book than I already have, I've left some things out. If you have any questions, please ask, and I wish you the best on your school project. Good luck.

Thanks,
Matt.
 
ShinySwords said:
two quick questions

Anyone know an easy way to estimate the BTUs produced by a certain computer?

Since you have discussed this alot even before i decided to try it, what kind of liquid would be best?
Click to expand...

The way I solved this was to take the Wattage output of all your submerged components, and convert it to BTU's. I found it took almost three times the cooling capacity the rid the system of the heat. So, if your system uses generates 300 Watts of thermal output, you convert that to BTU's using the forumla: Watts X 3.413. This gives you a little over 1000 BTU's. Using the rough 3 to 1 idea, you find that you need at least 3000 BTU's of cooling capacity to efficently cool 1000 BTUs of heat generation. As a rule of thumb, a 5 to 1 ratio seems to work very well, hence the mention of the 5200 BTU A/C in my last post. This will keep the compressor from working at 100% capacity, and with it cycling on and off, you can reduce your power consumption of the system.

Matt.
 
One other thing. I found that the fan on the A/C was insanely loud, so my last design got rid of the large fan (which sucked quite a bit of power on it's own), and converted the condensor to use six 120MM fans. This allows the fans to be triggered and controlled by your motherboard/power supply, and cuts down on noise significantly. If you want to get really crazy, you can write a program to use the thermal probes on your motherboard and use either a serial or other output to trigger a relay which will turn the A/C compressor on and off. This allows you pinpoint control over your coolant temperature. Taking it one step further, you can set what temperature you want the system to cool to, and overclock the system using Clockgen based on CPU temperature.

Matt.
 
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