Help for pump selection on oil-cooling.

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May 12, 2020
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Hello,


--Before starting, I won't answer to any details right now, in order to avoid off-topics, but I will post everything once my project is complete.--


The for-now details, my questions and my preliminary testing:

I want to liquid-cool my system WITHOUT water. I am using oil, and I need some expert advice on selecting mainly the pump, and a heat exchanger (if possible). The oil is @ 20 cst and I need a pump to push that oil through a cpu and gpu waterblock, be small (max size about as the pump below in my test) and silent. Second, I need a compact all copper heat exchanger, brazed, 10 plates max, 2kw max or the nearest) More on this later.

So far, I got an old P4 @ 2.6 to be the testbench, a simple single radiator (with 140mm fan), a basic generic waterblock (alluminium, 40x40), the head/waterblock from a faulty antec kuhler h2o 650 (yeah, the frankenstein AIO, just took the part that goes to the cpu) and a generic TMC-06301 noisy AF pump.

The P4 @ 2.66ghz has 66.1w tdp. Overclocking it @ 3ghz (that's the best the generic mobo could do), I linear project about 75w tdp, but I know that there is NO linerar corellation, so I hope that the tdp is higher than this.

At about 32c ambient temp (outdoors, shadow), using first the generic block I got 51c under load (using furmark's cpu burner, I know its "light" vs prime95, but whatever). Swapping the basic block with the antec one, I got 38c-41c !!! (core temp didnt show values between 38 and 41). Without the fan on the radiator I got max 48c. All readings for a period of half an hour.

I believe that the testing was success! Keep in mind that the oil in the test flows through the radiator. In my system I will have it pass through a heat exchanger and cool it via water. Also, the antec waterblock has huge restriction: 90deg for inlet, another 90 to turn right and pass through the microfins that are parallel to the inlet/outlet, another 90 to turn again right, and another 90 to go to the oulet. The flow of the antec block was very low compared to the basic block, but the results are beyond my expectations.

About the pump I used in the test, it has 378LPH flow rate. I have my thoughts for a D5 pump, that has 1350LPH flowrate, but here I need your thoughts.
 
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cdabc123

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I think a d5 would work just fine.

Any reason not to cool the oil below ambient with a phase change if you plan on cooling the oil with a intercooler anyways?
 
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I think a d5 would work just fine.

Any reason not to cool the oil below ambient with a phase change if you plan on cooling the oil with a intercooler anyways?
I don't want to go sub-ambient. The exchanger will cool the oil via water. I 'll explain this later on.
I have been running all sorts of Alphacool D5 pumps and reservoirs fur years with great success. Not the exact spec rez below, but that ought to get you started.

https://www.amazon.com/Alphacool-Eisbecher-Reservoir-Eispumpe-13307/dp/B076DG4R58/

The link has a VPP755 not d5. I only hear the best for the D5, but I don't know if it safe to assume that 1350lph (https://www.ekwb.com/blog/which-pump-should-you-use-d5-or-ddc/) is going to be good for my setup. I saw a dual D5 kit and think that if one D5 is not enough for classic water-cool then what I need for oil?
 

FrgMstr

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I don't want to go sub-ambient. The exchanger will cool the oil via water. I 'll explain this later on.


The link has a VPP755 not d5. I only hear the best for the D5, but I don't know if it safe to assume that 1350lph (https://www.ekwb.com/blog/which-pump-should-you-use-d5-or-ddc/) is going to be good for my setup. I saw a dual D5 kit and think that if one D5 is not enough for classic water-cool then what I need for oil?
Sorry, on my phone. Statement stands, ignore the link. :)
 

cdabc123

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I don't want to go sub-ambient. The exchanger will cool the oil via water. I 'll explain this later on.


The link has a VPP755 not d5. I only hear the best for the D5, but I don't know if it safe to assume that 1350lph (https://www.ekwb.com/blog/which-pump-should-you-use-d5-or-ddc/) is going to be good for my setup. I saw a dual D5 kit and think that if one D5 is not enough for classic water-cool then what I need for oil?
Please explain. Seems like alot of work for the same results as basic watercooling. And oil won't freeze ;)
 
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When I was testing, I stopped the pump to see the effect. The temps rose immediatelly, so I really gonna need redundacy or a killswitch, but with water you can work with very little flowrate. I don't know what happens if a pump stops in a waterloop, but water equalizes across the loop in no time.
 

cdabc123

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When I was testing, I stopped the pump to see the effect. The temps rose immediatelly, so I really gonna need redundacy or a killswitch, but with water you can work with very little flowrate. I don't know what happens if a pump stops in a waterloop, but water equalizes across the loop in no time.
If water stops in a loop the block will heatsoak until the processor hits its thermal limits.

You dont need much flow but you need some. There is little benifit to extra flow at a point
 

cdabc123

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True for water. For oil it needs to be a little more. So d5 all the way?
Yup if you dont care about noise a d5 can move plenty of fluid at max speed and tones down nicely. As a centrifuge pump abit of viscosity shouldn't pose much of a issue.

Why not use a small mercury loop instead?
 

Nobu

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I don't think most common water cooling parts are intended to be used with oil, let alone mercury. Seems like a lot of potential for a nasty spill / fire / toxic situation....
Yeah, the pump might be fine (alphacool's datasheet says water/gycol mix up to 50% is fine, "other media on request"), but you'd definitely want to ensure any plastics and orings in the loop won't react with the oil or otherwise break down on contact.
 
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Mercury in the loop, never thought of this, but of course it is out of the question (although it has good thermals, we have to give it on that). The oil I am using is not going to interact with any plastics and o-rings (for o-rings not so sure but if its good for plastics I suppose it is good for them too).
 

Axman

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Mercury is basically a solvent for electronics, I don't know why anyone would use it. Also, it's toxic. And expensive. And heavy.
 
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Been searching, but what about ddc pumps? It seems that most ppl just go for d5, but from what I read, ddc might be more suited for my "oily" setup as it has higher pressure..
 

DWolvin

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If the oil has higher viscosity than water the extra pressure of DDC pumps might help, but a pair of D5s will probably be fine and certainly move a decent amount of oil.

But 'oil' is about as specific as 'liquid'. What are you planning to use?
 
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