How big is too big?

[SureFoot]

*They* have quite a lot of expericence:
http://www.overclockers.com/articles599/
Also this was the topic of a basic experiment at university. I won't set up a lab experiment just to convince 2 persons i don't even know, so try to get in touch with a local university and ask a local prof to show you... I know a few but you'll have to travel to Europe to see them

 

[matttheniceguy]

Not the reason. While what you say is correct, it dosn't apply here. The amount of heat dissipated is a constant. You will always dissipate the same amount of heat out of the cpu, always. The law of conservation of energy can't be broken either. It is the temperature that the dissipation takes place at, that is the concern. This depends on the radiator. The radiator is more efficient at high temperatures, less at cooler temperatures for the very reason you just gave. The cooling system will adjust temperature until the radiator disipates heat at the same rate as the cpu is producing it, which remember is CONSTANT.
I'm not adding anything to the flow debate. I can tell myself all day long that higher flow rates are better, which I believe, but I wouldn't argue it without experimental proof.

I was speaking more in the lines of, if you had a hot chunk of metal and wanted to cool it. Of course the amount of heat disipated is constant for a constant cpu load, and this is all about the thermal resistance leading to the temperature difference required to cause that heat transfer, but the principals are the same.

 

[uthungover]

matttheniceguy, I understand what you are talking about, It just dosn't apply. What you should have said is what you just said, "and this is all about the thermal resistance leading to the temperature difference required to cause that heat transfer". It is the thermal resistance through the entire system, i.e, from the cpu to the room air.

SureFoot, thanks for the article. I don't need a university, I'm almost setup to do the experiment myself. I have a fairly high flow pump in my system, here are the specs:

Little Giant 2-MDQ-SC Quarium Series 2, Magnetic Drive Pressure Pump for Marine Aquarium, Fresh-water or Marine Aquariums 90-140 gallons. 465 gph/3ft., 410 gph/6ft., 250 gph/12ft., 14.4ft. max head. 1/2" FNPT in & 1/2" MNPT out..

I'll have to dig up a motor control, flow meter, and an accurate thermometer. Doing the experiment on a computer wc system would be a pure experiment, all variables acounted for. I agree, doing this to win an argument would be point less and the experiment could be biased. I would do this for fun. I am a scientist, this is what I do.

 

[SureFoot]

For a good variable flow test setup, see Bill Adams setup or now, Phaestus one on Procooling. They do it, like it should be done by everyone, i.e. like it's done in R&D labs or scientific research, for the most unbiased results.

 

[snwman]

dont think of it as how fast the water is moving though the block, think of it as how fast the cooled water is replacing the warm water in the block thus effectively cooling the block more?

 

[Mike89]

Man what a good thread, even though a lot of this stuff is over my head.

I have a question. I was also under the false impression that the slower the water moved through the radiator, the cooler the system would be.

So. Is there an actual downside to the size of the radiator at some point? Like I would assume a radiator the size of 2 120 fans would cool better than one the size of 1 120 fan. Or one that would be the size of 4 120 fans would beat both.

Now I'm beginning to wonder.

 

[SureFoot]

Man what a good thread, even though a lot of this stuff is over my head.

I have a question. I was also under the false impression that the slower the water moved through the radiator, the cooler the system would be.

So. Is there an actual downside to the size of the radiator at some point? Like I would assume a radiator the size of 2 120 fans would cool better than one the size of 1 120 fan. Or one that would be the size of 4 120 fans would beat both.

Now I'm beginning to wonder.

Actually airflow is way more important for a rad, than water flow. What has been shown as well is that a 2x120mm is not much more restrictive than a 1x120mm rad, it depends on their construction, etc. And even in the case of identical construction (just longer channels) the increase in water flow restriction is so small, that it is way overcompensated by the increase in air flow. So yes a 4x120 would beat both. You'll hit the size limit when the water flow restriction becomes relevant enough (i.e. it represents half of the head of your pump, for example, just throwing a random figure).
Also consider than some bigger heater cores are single pass, as opposed to conventional double-pass smaller heater cores. The single pass flow restriction is of course way less than the double pass, hence a better overall efficiency. That's why the hardcore crowd is often looking for single-pass heatercores

 

[Mike89]

Thanks. I'm getting ready to build my own with the res, rad, and pump all external (on a platform outside the case). I was planning on getting the Danger Den 2x120 heater core being it's a lot cheaper than the Black Ice 2x120. Is there an actual advantage to using the Black Ice 2x120 over the 2x120 heater core being the Black Ice on is about 3 times the cost?

I've never heard of a 2x120 single pass rad. Is there such a thing?

 

[SureFoot]

Is there an actual advantage to using the Black Ice 2x120 over the 2x120 heater core being the Black Ice on is about 3 times the cost?

You'll get the sticker, and the brand name. Geeks at LANs will recognize it. And your wallet will feel lighter. Ah and it has a mounting system. Apart from that, nothing else. BlackIce is just a branded heater core.

I've never heard of a 2x120 single pass rad. Is there such a thing?

Ah good question, my new 2x120 is double pass indeed, and so is the one sold by DDen. Folks @ procooling have a big sticky thread with a lot of references though, and they list all single pass heater cores they find. Try there (i'm lazy) i'm sure i've seen pics of some so they *do* exist.

 

[greenman100]

I've never heard of a 2x120 single pass rad. Is there such a thing?

I have one, fedco 2-342, $28

 

[Mike89]

Care to provide a link where you got it?

 

[a c i d.f l y]

clocker2: You are incorrect. The reason the temps rise when you remove a thermostat is because a radiator isn't efficient enough to remove the continuous heatflow. A thermostat in a car sets a balance between cooling and heating of the engine. If you have a beefy radiator, and high-flow -- your cooling increases given you have enough airflow through the radiator. Not to mention if the heat from your radiator sits there -- your increased flow goes nowhere -- just back through the tubes, adding more and more heat to the radiator.

I think you lost your idea on the heating up by a fully removed thermostat -- I just explained why this is: you would need an increase in airflow through your radiator. Again, it goes back to where the heat is eventually being transferred: THE AIR. Increasing flow benefits you NONE, if your radiator doesn't have the air-flow cooling it down.

I actually finished reading this and have to give my respect to eXcess.

If your water flow is higher, your air-flow needs to be higher, and your radiator needs to be bigger. 'nuff said. Of course there is a peak on this -- ambient air. This is our alpha, or tangent. The peak with which watercooling by itself -- MAXES OUT.

If this doesn't explain things -- I feel all is lost.

Thanks,
-Frank

 

[clocker2]

clocker2: You are incorrect.

Acidfly, you are beating a dead horse.
For just a short while I shall join you.

I thought that it had been decided that the car-PC comparison was invalid.

If not,it doesn't matter anyway.

Still, you might want to take up your theory with SureFoot as I suspect that he would have to disagree.
All other factors remaining the same...."more flow=better heat transfer.ALWAYS."
This does not allow for (or require) increasing anything...not the radiator size, not the airflow....nothing.
More flow should result in better cooling.
Granted, optimising the other components to take advantage of the increased flow might increase the benefits even more, but the increased flow, in and of itself, should result in an improvement, however minimal.
You can try to square this with what you'll experience by removing the thermostat any way you wish.
I've given up.

Over and out.

 

[greenman100]

Mike89:

You should be able to do the legwork, but I am in a giving mood, so Autozone carries it, and it's from a '79 Surburban K10 truck afaik....the 2-342 is what matters.

Clocker2/Acidfly:

What you are failing to take into account is the boiling point of water. The reason a car may overheat when the thermostat is removed is the following:

1. Greater flow results in better engine block to coolant heat transfer
2. Coolant temps may rise past 100C/212F(or whatever the antifreeze/watermix is set at). If this happens, liquid turns to steam, and results in engne overheating.

if your computer's coolant turns to steam, your processor is long gone.

Other than that, the horse is beaten.

 

[greenman100]

clocker2:
If your water flow is higher, your air-flow needs to be higher, and your radiator needs to be bigger. 'nuff said. Of course there is a peak on this -- ambient air. This is our alpha, or tangent. The peak with which watercooling by itself -- MAXES OUT.

wrong, unless said coolant gets to boiling point

if waterflow is higher, water temps will be higher, resulting in a greater deltaT, resulting in better cooling

 

[Mike89]

You should be able to do the legwork, but I am in a giving mood, so Autozone carries it, and it's from a '79 Surburban K10 truck afaik....the 2-342 is what matters.

Well I'm glad you were in a giving mood dude, cause I sure don't know where I would have found that out. Thanks. I'm new into this water stuff and still trying to decide if I'm going to take the plunge. I am doing a lot of reading on it now, where before I wasn't.

On that rad. What size fittings are on it? (if you're in a giving mood still) heh heh.

Also, this is probably a dumb *** question but could you explain what is the difference between a single and double pass rad? Sounds like the double pass is making two loops between the intake and outtake (a lot more water travel), where the single pass is only making one?

 

[greenman100]

Well I'm glad you were in a giving mood dude, cause I sure don't know where I would have found that out. Thanks. I'm new into this water stuff and still trying to decide if I'm going to take the plunge. I am doing a lot of reading on it now, where before I wasn't.

On that rad. What size fittings are on it? (if you're in a giving mood still) heh heh.

Also, this is probably a dumb *** question but could you explain what is the difference between a single and double pass rad? Sounds like the double pass is making two loops between the intake and outtake (a lot more water travel), where the single pass is only making one?

The only dumb question is the one that goes unresearched.

First of all, let me explain the reasoning behind my post. If you go here and read, especially toward the end of the thread, you'll see what I'm talking about.

That said, I'm glad you're researching singlepass vs. dual pass, and that in itself makes me want to explain, because it means someone is attempting to explore something they do not understand fully.

a singlepass heatercore has an inlet on one side and an outlet across the heatercore on the other side.

a dualpass heatercore has the inlet and outlet ont he same side, and a tank directly across.

so, if you are still visualizing what is going on, a dualpass heatercore has 4 times the flow resistance of a singlepass. (think, twice the length for coolant to travel, and half the width.)

go to procooling.com's forums, check out the sticky on singlepass rads

a word or warning....billa, cathar, and phaetsus, along with others, are tired of seeing the same questions...so read and search before posting.

personally, I was vert tenative about watercooling...I spent about $130, and ended up with a setup that dropped temps about 17C at less noise than my aeroflow HSF.

I'm also a mechanical engineering major, so this is all very interesting to me. read up, and THEN post.