Two Loops, One radiator

I'm planning on cooling CPU, NB and Gfx and seeing as many watercooling blocks, especially some of the best CPU blocks, are quite restrictive, wouldn't it be better to run 2 loops rather than one.

I'm gonna be using the Typhon III reservoir and from there run two loops like this:

Res -> Radiator -> Res
Res -> CPU -> NB -> Gfx -> Res

Depending on how restrictive the full Gfx block is that might go onto the radiator loop too.

My reason for doing this is that then there wouldn't be any flow restriction on the radiator loop, like there would be if for example the CPU was in the same loop, and this should result in maximum heat transfer.

Would there be any problems doing this? The only potentiel problem I can see is if the water doesn't get mixed well enough in the reservoir and alot of the warm water from the non-radiator loop would be send round and round. Considering that the Typhoon III is designed by a real enthuisiast and not some company clown i don't expect this to be the case though.

Since i don't think i've ever seen this before I'm kind of thinking I'm overlooking something here, enlighten me :D

Did you forget your pump? Keep it simple, res-pump- then whatever routing gives you the shortest runs of tubing.

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Originally Posted by hellcamino

Did you forget your pump? Keep it simple, res-pump- then whatever routing gives you the shortest runs of tubing.

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Pumps are mounted on the res with Typhoon III.

I guess this would work, it seems a less than optimal solution though as far as flow rates are concerned. You will have a really high flow rate through radiator and a really low flowrate through all the blocks which is exactly opposite of what you want. To an extent higher flow through blocks = lower temps, and lower flow through rad = lower temps.

It will be interesting to see though if you hookup a controller to each of the pumps the tuning options could make a significant difference finding optimal flow rate through the rad and optimal flow rate through the blocks seperately as long as you could get a decent flow through the blocks with just the one pump.

Edit: Giving it a second thought I'm not sure how well it would work with that particular res though because the inlet of the res is so close to the inlet of the pumps that the temps of water flowing through rad and water flowing through blocks on 2 seperate loops might never equalize or at least take an extremely long time to equalize which with the rad on a seperate loop would be really bad.

the first thing i thought when i read the topic is you have it completely backwards... how about one loop, two radiators!

but really, what youre doing is restricting the water's access to the radiator, which is the main point of having one. the water being restricted by the radiator happens because of the water being exposed to the maximum inner surface area of the radiator as possible, youre trying to create as much of an interface between the warm water and the cool walls of the radiator as possible.

if you only run some of the water through the radiator, youre submitting less of it to be dissipated into the outside air, while simultaneously submitting more of the water to the hot cpu block...

by using two radiators in one loop youre doing the opposite, all of the water sees more radiator time, instead of less water seeing less radiator time.

EDIT whether or not it's two 'loops' it is still one body of water. what youre setting up is a complicated version of a loop with two pumps, one radiator, and a crapload of water. which wouldnt be so bad, but attempting to separate the ever-warming cpu water and the near-ambient radiator water, only relying on the reservoir to mix these, is making it worse.

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Originally Posted by bluehaze

Pumps are mounted on the res with Typhoon III.

I guess this would work, it seems a less than optimal solution though as far as flow rates are concerned. You will have a really high flow rate through radiator and a really low flowrate through all the blocks which is exactly opposite of what you want. To an extent higher flow through blocks = lower temps, and lower flow through rad = lower temps.

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I forgot the typhoon III is a pump top, my bad.


I would just slpit the loops and use two radiators myself.

I didn't know that lower flow rates through the radiator will yield better temperatures. That just seems plain wrong to me. Can anyone explain why this is? I would think that the more water goes through the radiator the more cooling I get.

If i had it all in one loop i would have really low flow rate through the entire loop along with the radiator.

AndrewZorn: This way I wouldn't restrict the flowrate through the radiator, that's the whole point. This way with two loops more water would flow through the radiator, since the flow won't be restricted by the cooling blocks that are way more restrictive than the radiator.

Bluehaze: I'm only going to use one D5 pump. And i wouldn't have a "really low flowrate through all the blocks". I would have the exact same flowrate as i would if the radiator was in the same loop and i only ran one loop total.

Guess the two main questions are:
Will the water be mixed well enough in the reservoir?
Do radiators really benefit from lower flowrates compared to higher?

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Originally Posted by hellcamino

I forgot the typhoon III is a pump top, my bad.


I would just slpit the loops and use two radiators myself.

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Well i appreciate your input but that's not really what i asked about ;)

Edit: My two last replies sounded a bit pissy. It wasn't meant like that but english isn't my first language and sometime i come across a bit angry.

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Originally Posted by troelsm

I didn't know that lower flow rates through the radiator will yield better temperatures. That just seems plain wrong to me. Can anyone explain why this is? I would think that the more water goes through the radiator the more cooling I get.

If i had it all in one loop i would have really low flow rate through the entire loop along with the radiator.

Bluehaze: I'm only going to use one D5 pump. And i wouldn't have a "really low flowrate through all the blocks". I would have the exact same flowrate as i would if the radiator was in the same loop and i only ran one loop total.

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The water gets cooled while moving through the radiator, you need to find an optimal speed in which the water has time to cool yet doesn't sit in the rad after it's already cooled as much as it is realistically going to cool while moving. If the water just blasts through the rad the air doesnt have as much time to absorb the heat, if the water sits in the rad too long the air will absorb all the heat but the rest of the water will get hotter meaning the rad now has to remove more heat.

My point was with two pumps and two loops you could individually tune the speed of water through rad and speed through blocks. I think this would only work though with a bigger res and a fair distance from the inlet of res and inlet of pumps in order to have any chance at being effective as otherwise you will just end up recycling the same water through rad and the same water through blocks...I don't think the water temps would equalize.

And it's all a moot point if your only going to use one pump as it's impossible to run seperate loop through rad and seperate loop through the blocks with 1 pump.

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Originally Posted by troelsm

Well i appreciate your input but that's not really what i asked about ;)

Edit: My two last replies sounded a bit pissy. It wasn't meant like that but english isn't my first language and sometime i come across a bit angry.

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Thanks for the explanation or I wouldn't have responded again :P, a D5 running through only 3 blocks and a radiator will work just fine if the blocks are appropriately chosen for low restriction. Adding a second dummy loop running from the same pump won't help you out any and will actually hurt your temps. Water will take the path of least resistance so it would flow 90% through your rad and 10% through your blocks (a guess).

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Originally Posted by troelsm

Guess the two main questions are:
Will the water be mixed well enough in the reservoir?
Do radiators really benefit from lower flowrates compared to higher?

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You do have to remember the heat dissipates through the rad. You do need to allow the water some time in the rad for the heat to dissipate. Also though, if the flow rate is increased, the water would move faster, but would still spend same amount of total amount of time in the rad.

My biggest concern would be getting enough cooling with the fact that your loop is basically using the res as it rad.

If you are worried about flow, I would just get 2 220 rads and run 1 run rad CPU and the other MB GFX rad. I think that is the way the typhoon was designed to work, but I could be wrong. I think BoxGods or DB are the best people to put this question too. :up:

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Originally Posted by bluehaze

The water gets cooled while moving through the radiator, you need to find an optimal speed in which the water has time to cool yet doesn't sit in the rad after it's already cooled as much as it is realistically going to cool while moving. If the water just blasts through the rad the air doesnt have as much time to absorb the heat, if the water sits in the rad too long the air will absorb all the heat but the rest of the water will get hotter meaning the rad now has to remove more heat.

My point was with two pumps and two loops you could individually tune the speed of water through rad and speed through blocks. I think this would only work though with a bigger res and a fair distance from the inlet of res and inlet of pumps in order to have any chance at being effective as otherwise you will just end up recycling the same water through rad and the same water through blocks...I don't think the water temps would equalize.

And it's all a moot point if your only going to use one pump as it's impossible to run seperate loop through rad and seperate loop through the blocks with 1 pump.

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I would really like to see some sort of scientific data that shows the performance of a rad actually decreasing at some point where the flow gets too high. That really sounds bizare to me.

The thing about equalizing the temperature in the reservoir is what i'm most concerned with. Hopefully the guy (don't remember his nickname) who designed the typhoon III can comment on that.

How come i can't run two loops with only one pump out of the typhoon? Isn't both inlets and both outlets connected to the same "tank"?

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Originally Posted by troelsm

How come i can't run two loops with only one pump out of the typhoon? Isn't both inlets and both outlets connected to the same "tank"?

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The loops must match in terms of restriction or one will get much more flow than the other.

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Originally Posted by hellcamino

Thanks for the explanation or I wouldn't have responded again :P, a D5 running through only 3 blocks and a radiator will work just fine if the blocks are appropriately chosen for low restriction. Adding a second dummy loop running from the same pump won't help you out any and will actually hurt your temps. Water will take the path of least resistance so it would flow 90% through your rad and 10% through your blocks (a guess).

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That's a good point. I didn't really think about that but it's actually quite logical. Guess that pretty much settles it :)

A little side question: Say i were to run one loop with, CPU 350, Gigabyte ex-58 NB block, a full gfx block (probably the koolance gtx 295 block) and the swiftech mcr320. Would that be allright to run in one loop or is that too restrictive?

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Originally Posted by troelsm

I would really like to see some sort of scientific data that shows the performance of a rad actually decreasing at some point where the flow gets too high. That really sounds bizare to me.

The thing about equalizing the temperature in the reservoir is what i'm most concerned with. Hopefully the guy (don't remember his nickname) who designed the typhoon III can comment on that.

How come i can't run two loops with only one pump out of the typhoon? Isn't both inlets and both outlets connected to the same "tank"?

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It's physically possible to hook it up like that but it won't work.

As far as scientific data your on your own but just given the general nature of how a radiator works water passes through it and as it passes through it air blowing through the radiator absorbs the heat. So the faster the water moves through the radiator the less time their is for the air to dissapate that heat.

When everything is on one loop you have to find a happy medium within which the water moving through the blocks has doesn't have enough time to overheat and the water moving through the radiator has enough time to dissipate the heat.

With seperate loops you dont have this restriction and could individually tune the speed of water through the rad and the speed of water through the blocks.

Only reason I think this might work is because you would effectively have the loop being fed with water cooled via a different loop that has lower temperatures. Would be interested to see the results if anyone has ever tried this...probably doesn't work though or else the method would be all over the place by now :)

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Originally Posted by bluehaze

It's physically possible to hook it up like that but it won't work.

As far as scientific data your on your own but just given the general nature of how a radiator works water passes through it and as it passes through it air blowing through the radiator absorbs the heat. So the faster the water moves through the radiator the less time their is for the air to dissapate that heat.

When everything is on one loop you have to find a happy medium within which the water moving through the blocks has doesn't have enough time to overheat and the water moving through the radiator has enough time to dissipate the heat.

With seperate loops you dont have this restriction and could individually tune the speed of water through the rad and the speed of water through the blocks.

Only reason I think this might work is because you would effectively have the loop being fed with water cooled via a different loop that has lower temperatures. Would be interested to see the results if anyone has ever tried this...probably doesn't work though or else the method would be all over the place by now :)

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I see your point that the water needing to have some time to dissipate the heat, but isn't it kinda like saying that if you put your head out the window of a moving car, at some speed it will start to get less cold because the air hitting you dont have enough time to draw the heat off your face?

You could probably say that if you just look at a specific amount of water going through the radiator the water going very fast wouldn't be cooled very much, but that wouldn't matter since there are so much more going through.

Well the point about the water going through the least restrictive loop is valid so i guess it doesn't really matter :)

All I will say is with the T3 you want TWO LOOPS . . . .period. Anyone here who says otherwise . . .even someone like our senior people . . .are wrong if they say one loop with a T3 is better than two. What is on those loops is another matter.

I don't think you ever got over to that other theard Troelsm, but here you go from:

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Originally Posted by millertime359

Will all this talk over running seprate loops off of this, could you have a loop that is rad only and a loop with your CPU and GPU blocks only. I wouldn't think it would work, but the T3 isn't your standard res will it allow you to do that?

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Originally Posted by BoxGods

I would think that it WOULD work actually. Keep in mind that the water in the T3 is exchanged almost 16 times a minute. A larger rad would do better as its more restricted likely.

It is cool that people are starting to see the potential here. Even I have no idea what the limits are on the T3 because there are all these new variables. Build people cool tools and they will in turn build things you can't even imagine.

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Originally Posted by bluehaze

...If the water just blasts through the rad the air doesnt have as much time to absorb the heat, if the water sits in the rad too long the air will absorb all the heat but the rest of the water will get hotter meaning the rad now has to remove more heat.

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This could not be more incorrect. Please do some reading before blasting 'fantasy physics' on a public forum.

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Originally Posted by bluehaze

As far as scientific data your on your own but just given the general nature of how a radiator works water passes through it and as it passes through it air blowing through the radiator absorbs the heat. So the faster the water moves through the radiator the less time their is for the air to dissapate that heat.

When everything is on one loop you have to find a happy medium within which the water moving through the blocks has doesn't have enough time to overheat and the water moving through the radiator has enough time to dissipate the heat.

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So then you're just making all this up? This has been discussed to death for many years. I wish I knew how this false myth keeps getting perpetuated.

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Originally Posted by nikhsub1

I wish I knew how this false myth keeps getting perpetuated.

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This is the real $250,000,000,000 question. :yepp:

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Originally Posted by nikhsub1

This could not be more incorrect. Please do some reading before blasting 'fantasy physics' on a public forum.

So then you're just making all this up? This has been discussed to death for many years. I wish I knew how this false myth keeps getting perpetuated.

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:shrug: Where were you during all the discussion last night? :ROTF: So how does it work then? Because i'm still confused about why it wouldn't work if you have two seperate loops and are able to adjust flow through the rad seperately from flow through the blocks. And I have looked and haven't seen this discussed anywhere. Would love to read about it though if you happen to know where I might find some info :up:

Reason I am confused is if you raise your fan speed thus increasing air flow through the radiator your temps go down, so wouldnt lowering water flow through the rad have the same effect as increasing air speed as long as the water was flowing through the rad independently of the blocks? But I guess if this is the case then you now have increased volume of water flowing through the blocks as compared to volume of water flowing through the rad regardless if they are seperate loops because they are still sharing the same water source...

I don't know man...it's all pretty confusing.

Cheers

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Originally Posted by bluehaze

:shrug: Where were you during all the discussion last night? :ROTF: So how does it work then? Because i'm still confused about why it wouldn't work if you have two seperate loops and are able to adjust flow through the rad seperately from flow through the blocks. And I have looked and haven't seen this discussed anywhere. Would love to read about it though if you happen to know where I might find some info :up:

Reason I am confused is if you raise your fan speed thus increasing air flow through the radiator your temps go down, so wouldnt lowering water flow through the rad have the same effect as increasing air speed as long as the water was flowing through the rad independently of the blocks? But I guess if this is the case then you now have increased volume of water flowing through the blocks as compared to volume of water flowing through the rad regardless if they are seperate loops because they are still sharing the same water source...

I don't know man...it's all pretty confusing.

Cheers

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Im pretty sure nikhsub1's comment to you was regarding your theory about flow and not the loops of the T3. I posted the equation last night for you in the other thread but you didn't comment on it. Your logic "sounds" plausible in the sense that slowing the water through the rad should pull more heat but this isn't actually the case. It has been my whole point to you that slowing things down does NOT make things cooler. Look at the equation and you will see that amount of heat transferred is directly proportional to flow.

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Originally Posted by bluehaze

Reason I am confused is if you raise your fan speed thus increasing air flow through the radiator your temps go down, so wouldnt lowering water flow through the rad have the same effect as increasing air speed as long as the water was flowing through the rad independently of the blocks?

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So you acknowledge that more airflow = better temps but slower water flow should equal better temps? Does this theory not sound contradictory to you? You say that the more time the water spends in the rad will cool better correct? OK, lets look at it like this then. You have 2 identical loops except one is running 1GPM and the other is running at 2GPM. At 1GPM the water spends twice as long in the rad as compared to 2GPM, however, at 2GPM the water passes through the rad twice as often. So now answer me which loop spends more time in the rad?

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Originally Posted by Darth_Penguin

Im pretty sure nikhsub1's comment to you was regarding your theory about flow and not the loops of the T3.

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:yepp:

dunno nikhsub1, maybe if the pump was so crappy that it comes on and off, then water would sit in a loop and allow for better heat transfer?

:D

excuse my sillyness...

maybe bluehaze is looking at stationary water boiling in a pot...
bluehaze, the cooling system in your loop does not process in batches, it constantly flows and while if you look at how little amount of heat is absorbed in a block in a given time, you have to take into factor the flow rate...

dunno if this makes sense...

if the loop were to remove temp in batches, then i think the temp of your cpu will spike up and down... also, bigger volume capacity on the blocks would be needed.. no?

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Originally Posted by nikhsub1

So you acknowledge that more airflow = better temps but slower water flow should equal better temps? Does this theory not sound contradictory to you? You say that the more time the water spends in the rad will cool better correct? OK, lets look at it like this then. You have 2 identical loops except one is running 1GPM and the other is running at 2GPM. At 1GPM the water spends twice as long in the rad as compared to 2GPM, however, at 2GPM the water passes through the rad twice as often. So now answer me which loop spends more time in the rad?

:yepp:

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Well of course the 2gpm what confuses me is not that, what confuses me is that lowering the flow of the water by proportion increases the volume of air and vice versa. So if you are only capable of maintaining a certain volume of air wouldn't lowering the volume of water result in decreased temps?

not to be confused with that fact that many people do turn their pumps down from the max to get the best results, but this comes from the balancing of heat dump from the pump vs flow

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Originally Posted by bluehaze

Well of course the 2gpm what confuses me is not that, what confuses me is that lowering the flow of the water by proportion increases the volume of air and vice versa. So if you are only capable of maintaining a certain volume of air wouldn't lowering the volume of water result in decreased temps?

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I've read this 4 times and still don't know what you mean. How does water flow affect airflow? They are independent and don't directly affect one another although they must BOTH be taken into consideration for best performance.

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Originally Posted by kinghong1970

maybe bluehaze is looking at stationary water boiling in a pot...
bluehaze, the cooling system in your loop does not process in batches, it constantly flows and while if you look at how little amount of heat is absorbed in a block in a given time, you have to take into factor the flow rate...

dunno if this makes sense...

if the loop were to remove temp in batches, then i think the temp of your cpu will spike up and down... also, bigger volume capacity on the blocks would be needed.. no?

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No I understand that now because it is a closed loop system the volume of water passing through the rad is directly proportional to the volume of water passing through the blocks so lowering the volume of water through rad while increasing the volume of water through blocks would actually result in less water being cooled and more water being heated.

What I was thinking was that if you had seperate loops you could lower the volume of water passing through the rad thus increasing the volume of air to water.

I don't know though I don't have any education in engineering and only high school science so I am way behind on the learning curve here :yepp:

As far as the radiator is concerned, it is removing X wattage of heat from the water contained inside it over any given amount of time. Running the water through the radiator twice as fast, only means that you will take half the heat out of twice the volume of water... making the whole issue a wash.

Think of it this way... if you have a light bulb that needs 24 Watts of power to run, and it doesn't care what voltage it is given... Which is more efficient, 240v@0.1Amps or 120v@0.2Amps ? In a perfect world, there is no difference between the two, you are still using 24 Watts. In our less-than-perfect world, the 240v is more efficient since you lose less power in your transport (wires) due to resistance...

Comparing this to watercooling, that resistance is friction from the water running through your tubing and blocks. The more flow you have (much like voltage in a power line) the less effect your resistance will have on the total. No matter what, the radiator will still dissipate the same wattage of heat.

Another thing to consider is, radiators are more efficient the hotter they are. If you leave the water in the radiator too long, you reduce the radiator's efficiency because the water is already cooled by the time it gets to the outlet.

Basically, the difference between the two will be negligible unless you get to extremes, like slowing your flow rate to a crawl... but the higher flow will be slightly better in all cases, due to lower loss to friction in the tubing, and making the radiator operate at a higher efficiency part of it's curve.

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Originally Posted by bluehaze

No I understand that now because it is a closed loop system the volume of water passing through the rad is directly proportional to the volume of water passing through the blocks so lowering the volume of water through rad while increasing the volume of water through blocks would actually result in less water being cooled and more water being heated.

What I was thinking was that if you had seperate loops you could lower the volume of water passing through the rad thus increasing the volume of air to water.

I don't know though I don't have any education in engineering and only high school science so I am way behind on the learning curve here :yepp:

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bluehaze, correct me if i'm wrong... but i think what you're getting at is looking at figures to increase the efficiency of amount cooled by looking at amount of air flow vs amount of water...

but see, regardless of how much water you have, the loop requires a FIXED amount of water to have a continuous loop with no air bubbles in order to get it to work... if you have more water, it just sits in the reservoir and gets used as needed... if you have too little water, it is basically a T-Line... so there is only so much you can decrease the amount of water...

efficiency of your loop will be dictated more by your flow rate of water and air flow over your radiator...

now i don't know if i make any sense... lol

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Originally Posted by kinghong1970

bluehaze, correct me if i'm wrong... but i think what you're getting at is looking at figures to increase the efficiency of amount cooled by looking at amount of air flow vs amount of water...

but see, regardless of how much water you have, the loop requires a FIXED amount of water to have a continuous loop with no air bubbles in order to get it to work... if you have more water, it just sits in the reservoir and gets used as needed... if you have too little water, it is basically a T-Line... so there is only so much you can decrease the amount of water...

efficiency of your loop will be dictated more by your flow rate of water and air flow over your radiator...

now i don't know if i make any sense... lol

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LOL Yes you got it, that was the mistake I have been making, being the volume of water is fixed in a closed loop system you cant alter the proportion of air to the proportion of water without increasing or decreasing the air flow. Yay I think I got it now :ROTF:

I guess it's easy to get confused because natural tendency is to consider an open loop with unlimited water supply but when it is a closed loop and your dealing with a fixed volume of water everything changes.

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Originally Posted by 3Z3VH

As far as the radiator is concerned, it is removing X wattage of heat from the water contained inside it over any given amount of time. Running the water through the radiator twice as fast, only means that you will take half the heat out of twice the volume of water... making the whole issue a wash.

Think of it this way... if you have a light bulb that needs 24 Watts of power to run, and it doesn't care what voltage it is given... Which is more efficient, 240v@0.1Amps or 120v@0.2Amps ? In a perfect world, there is no difference between the two, you are still using 24 Watts. In our less-than-perfect world, the 240v is more efficient since you lose less power in your transport (wires) due to resistance...

Comparing this to watercooling, that resistance is friction from the water running through your tubing and blocks. The more flow you have (much like voltage in a power line) the less effect your resistance will have on the total. No matter what, the radiator will still dissipate the same wattage of heat.

Another thing to consider is, radiators are more efficient the hotter they are. If you leave the water in the radiator too long, you reduce the radiator's efficiency because the water is already cooled by the time it gets to the outlet.

Basically, the difference between the two will be negligible unless you get to extremes, like slowing your flow rate to a crawl... but the higher flow will be slightly better in all cases, due to lower loss to friction in the tubing, and making the radiator operate at a higher efficiency part of it's curve.

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Great description. :up:

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Originally Posted by bluehaze

LOL Yes you got it, that was the mistake I have been making, being the volume of water is fixed in a closed loop system you cant alter the proportion of air to the proportion of water without increasing or decreasing the air flow. Yay I think I got it now :ROTF:

I guess it's easy to get confused because natural tendency is to consider an open loop with unlimited water supply but when it is a closed loop and your dealing with a fixed volume of water everything changes.

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he he he...

1) hook up your loop to tap water and drain out your toilet...
2) fixed/closed loop

if the following is fixed:
a) temp of water
b) air flow over rad
c) flow rate in loop

then i think your resulting temp will be the same... except, choice 1 will give you bigger water bill...

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Originally Posted by kinghong1970

he he he...

1) hook up your loop to tap water and drain out your toilet...
2) fixed/closed loop

if the following is fixed:
a) temp of water
b) air flow over rad
c) flow rate in loop

then i think your resulting temp will be the same... except, choice 1 will give you bigger water bill...

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Right but see that's where the confusion came in, plan was to have 2 pumps so you could have lower flow through rad and higher flow through blocks. :rofl:

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Originally Posted by 3Z3VH

As far as the radiator is concerned, it is removing X wattage of heat from the water contained inside it over any given amount of time. Running the water through the radiator twice as fast, only means that you will take half the heat out of twice the volume of water... making the whole issue a wash.

Think of it this way... if you have a light bulb that needs 24 Watts of power to run, and it doesn't care what voltage it is given... Which is more efficient, 240v@0.1Amps or 120v@0.2Amps ? In a perfect world, there is no difference between the two, you are still using 24 Watts. In our less-than-perfect world, the 240v is more efficient since you lose less power in your transport (wires) due to resistance...

Comparing this to watercooling, that resistance is friction from the water running through your tubing and blocks. The more flow you have (much like voltage in a power line) the less effect your resistance will have on the total. No matter what, the radiator will still dissipate the same wattage of heat.

Another thing to consider is, radiators are more efficient the hotter they are. If you leave the water in the radiator too long, you reduce the radiator's efficiency because the water is already cooled by the time it gets to the outlet.

Basically, the difference between the two will be negligible unless you get to extremes, like slowing your flow rate to a crawl... but the higher flow will be slightly better in all cases, due to lower loss to friction in the tubing, and making the radiator operate at a higher efficiency part of it's curve.

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^Metaphor of the century^

And another way to look at it is:

If you increase flow, the water spends less time in the radiator getting cooled off, but it also spends less time in the CPU block getting heated up. If you decrease flow, your water will spend a lot of time in the radiator getting cooled off, but it will also spend even more time in the CPU block getting boiled! It all balances itself out for the most part.

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Originally Posted by 3Z3VH

As far as the radiator is concerned, it is removing X wattage of heat from the water contained inside it over any given amount of time. Running the water through the radiator twice as fast, only means that you will take half the heat out of twice the volume of water... making the whole issue a wash.

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Not really. The flow rate of the water and the air will determine how efficient the rad is, it will not be a wash, it will be very different at different flow rates.

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Originally Posted by 3Z3VH

Another thing to consider is, radiators are more efficient the hotter they are. If you leave the water in the radiator too long, you reduce the radiator's efficiency because the water is already cooled by the time it gets to the outlet.

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Your first sentence here is misleading. Radiators are most efficient when there is a large liquid to air temp differential. If the rad's water is at 50C and so is the air, the rad won't be efficient at all. If the air was 25C it would be. The second sentence makes no sense. This would apply to serial rads where the first rad in the loop would be more efficient than the second because the first rad already cooled the water some.

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Originally Posted by nikhsub1

Not really. The flow rate of the water and the air will determine how efficient the rad is, it will not be a wash, it will be very different at different flow rates.

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You're kidding right? It's a CLOSED loop, flow rate will have little affect outside of extreme highs and lows. To make it simple:

A train follows a circular track that loops in on itself - like many basic trainsets. Put the station at one point. If the train does 1 lap every 10 seconds, it'll spend 1 second travelling through the station each lap.

Now if the train does 1 lap every 20 seconds, it'll spend 2 seconds travelling through the station each lap.

But here's the rub, in the first instance if you increase the time measured to 20 seconds, then it spends exactly the same amount of time in the station as the second loop.

Numbers only:
1 lap every 20secs, 2 secs in station per 20sec
1 lap every 10secs, 2 secs in station per 20sec

Ultimately the flowrate doesn't make a major difference to the time water spends in the radiator, which is why flowrate doesn't make a difference.

Flowrate makes a difference with waterblocks, not radiators.

Lower flow doesn't help make a radiator perform better. The most important part of cooling is being ignored here, how the heat is transfered in the first place: Turbulence. Higher flow means more turbulence.

Can't use data from an actual loops, it'd have to be just a test loop where the only variable is the flow rate.

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Originally Posted by Adamantine

Lower flow doesn't help make a radiator perform better. The most important part of cooling is being ignored here, how the heat is transfered in the first place: Turbulence. Higher flow means more turbulence.

Can't use data from an actual loops, it'd have to be just a test loop where the only variable is the flow rate.

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I'd tend to think that too, more turbulence in the radiator translates into better transporting of heat to the radiator fins. If you stir a pot of water, does it come to a boil much faster than if you just leave it sit? I live in a Dorm and can't test this. :)

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Originally Posted by boogle

You're kidding right? It's a CLOSED loop, flow rate will have little affect outside of extreme highs and lows. To make it simple:

A train follows a circular track that loops in on itself - like many basic trainsets. Put the station at one point. If the train does 1 lap every 10 seconds, it'll spend 1 second travelling through the station each lap.

Now if the train does 1 lap every 20 seconds, it'll spend 2 seconds travelling through the station each lap.

But here's the rub, in the first instance if you increase the time measured to 20 seconds, then it spends exactly the same amount of time in the station as the second loop.

Numbers only:
1 lap every 20secs, 2 secs in station per 20sec
1 lap every 10secs, 2 secs in station per 20sec

Ultimately the flowrate doesn't make a major difference to the time water spends in the radiator, which is why flowrate doesn't make a difference.

Flowrate makes a difference with waterblocks, not radiators.

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I think you need to do some reading too. Step 1, reread what I wrote and what I was referring to. You asked me if I was kidding? Closed loop? Yes the assumption is a closed loop. And flow rate DOES make a difference in radiators. Please check your facts.

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Originally Posted by Kuntz

I'd tend to think that too, more turbulence in the radiator translates into better transporting of heat to the radiator fins. If you stir a pot of water, does it come to a boil much faster than if you just leave it sit? I live in a Dorm and can't test this. :)

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That is not easy to test that way. The reason (atleast thats what i think) why more turbulence = better heat transfer is because much more of the water is touching radiator.

I guess a good way to describe it is to try and look at the water from a molecular point of way and "travel distance".

Say we have two loops that both have a flow rate of 2 gpm. One has no turbulence (i know this is not possible but it's only to make the argument easier to understand) the other has a lot of turbulence.

Now they both have the same flowrate but the molecules in the one with turbulence would travel a much greater distance in one passing of the entire loop than one molecule in the non-torbulent loop would, since it would travel in a "straight" line. This means that the turbolent molecules would travel at a much greater velocity.

Therefore the molecules in the turbulent loop would touch the actual radiator more and thereby increase heat transfer.

I hope this is as understandable to people who read it as it is in my head :)

Edit2: Which in the end means that more flow = more torbulence = better heat transfer. This doesn't mean you can just add something to your loop to create torbulence and you'll see better numbers. The more torbuelence you got in the loop the more pumping power it takes to keep the same flow rate.

http://www.xtremesystems.org/forums/...d.php?t=226199

Bluehaze and everyone else that wonders. Read the above thread. Its a good one. It answers even more than you are asking.

First of all let's remember what the purpose of water cooling is: to move the heat from the hot parts of the computer to the outside of the case. We cannot destroy the heat, we can only move it. How is this accomplished? First we use a small amount of water to absorb the heat produced by the cpu in the cpu block. Then we move this quantum of water to the radiator where the heat is transferred through the fins of the radiator into the air. This cools the water back down. Now we send this same quantum of less hot water back to the cpu block to absorb more heat. And we do this over and over again. The faster we do it, the better. The more times per minute that you heat up the quantum of water and cool it off again the more cooling capacity your loop will have. Just like the fact that the faster the air is passing over the radiator the more heat will be transferred to the air. This situation is not analogous to trains, unless you have the trains loading and unloading passengers. Now the total passengers you load and unload over a full day, is a more analogous, if still inapt, to water cooling. Further the voltage in a light bulb is analogous to the head pressure of the pump, not the flow rate, which is analogous to the current in the wires. And finally, radiators do more work when there is more flow, and do less work when there is less flow. You would never want to slow the water down in a radiator, this would never provide you any benefit (in terms of cooling).

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Originally Posted by eth0s

First of all let's remember what the purpose of water cooling is: to move the heat from the hot parts of the computer to the outside of the case. We cannot destroy the heat, we can only move it. How is this accomplished? First we use a small amount of water to absorb the heat produced by the cpu in the cpu block. Then we move this quantum of water to the radiator where the heat is transferred through the fins of the radiator into the air. This cools the water back down. Now we send this same quantum of less hot water back to the cpu block to absorb more heat. And we do this over and over again. The faster we do it, the better. The more times per minute that you heat up the quantum of water and cool it off again the more cooling capacity your loop will have. Just like the fact that the faster the air is passing over the radiator the more heat will be transferred to the air. This situation is not analogous to trains, unless you have the trains loading and unloading passengers. Now the total passengers you load and unload over a full day, is a more analogous, if still inapt, to water cooling. Further the voltage in a light bulb is analogous to the head pressure of the pump, not the flow rate, which is analogous to the current in the wires. And finally, radiators do more work when there is more flow, and do less work when there is less flow. You would never want to slow the water down in a radiator, this would never provide you any benefit (in terms of cooling).

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I agree 100% with you that less flow will never achieve better temperatures. Though air over the radiator isn't a very good analogy to the water flowing through the radiator. This is because the air over radiator is an open system, and therefore it's all about how much air you can get over the radiator. In the case of the water, if it wasn't for the turbulence created by more flow the heat transfer curve would've flatten out at very low gpm because it's a closed system.

This is if we look away from turbulence for a second: I think the problem with your example is that (if i read it right) you seem to imply that more flow means that the blocks will heat up the quantum of water more times per minute. In a sense this is true but the problem in a closed system is that it wouldn't heat each quantum up as much as they would if the flow had been slower.. ie. the water goes through twice as fast but only moving half the heat each passing.

All this is cancelled by the turbulence the flow creates though. Just wanted to try and explain why you can't really compare it to fans on a radiator.

Quote:

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Originally Posted by [XC] riptide

http://www.xtremesystems.org/forums/...d.php?t=226199

Bluehaze and everyone else that wonders. Read the above thread. Its a good one. It answers even more than you are asking.

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Thanks for the link! Just briefly scanned the thread so far but it is easy to see why this all gets so confusing. Most everything with a closed loop system is so counter intuitive to the natural thought process. It seems to me if they are isolating temp drop accross the radiator only that it is not an accurate method of measurement as lower flow will definitely decrease temps in this measurement, that is what I was trying to say before with lowering the flow of water is equivalent to increasing the flow of the air accross the radiator only.

It would seem the best way to get realistic temp data would be to just plunk a meter in the res and measure during a certain time period of a sustained heat load. As if you try to measure at any 2 points you are eliminating a portion of the loop which plays a part in overall temps.

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Originally Posted by nikhsub1

Not really. The flow rate of the water and the air will determine how efficient the rad is, it will not be a wash, it will be very different at different flow rates.


Your first sentence here is misleading. Radiators are most efficient when there is a large liquid to air temp differential. If the rad's water is at 50C and so is the air, the rad won't be efficient at all. If the air was 25C it would be. The second sentence makes no sense. This would apply to serial rads where the first rad in the loop would be more efficient than the second because the first rad already cooled the water some.

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Stop worrying about the flow rate of the air. We are assuming the air flow rate is a constant, because no matter how fast/slow the water is passing through the loop, it will not make your fans spin faster. So the air flow rate is a constant.

Also, my sentence isn't misleading. I agree with you, they get more efficient as the delta between ambient and water temps increases. Now, when you are given a constant value as your ambient temperature, what is the only variable that will increase the delta between ambient and water temps ? That's right, the temperature of the water... meaning, the hotter the water, the more efficient the radiator will be, since the ambient is considered a constant (for the purposes of this conversation). Now read my sentence again, considering that the ambient temp is a constant.... The hotter the radiator is (due to water temps) the more efficient it is. Seems true to me !

Your radiator, with a constant air flow over it, using a constant ambient temp, will give a predictable cooling capacity, represented by wattage, which will look like a curve on a graph of liquid temp vs. heat dissipated. The higher the temp of the liquid, the more capacity your radiator has to dissipate it.

Thus, my oversimplified statement "The hotter the radiator is, the more efficient it is" is true for purposes of this conversation. And you only proved my point by your statement about the differential... if you let the water sit in the rad for, say, an hour it should get pretty close to ambient temp... do you think the radiator is still radiating warm air ? Nope. That is because it is no longer removing as much heat from the water. If you let the water temp get too close to ambient, the radiator will not be as efficient. Thus, the slower the water, the more time it has to get closer to ambient, thus, the less efficient your radiator will be. All the water that is waiting to get pumped through the radiator is getting hotter and hotter waiting for its turn to go through the radiator at such a slow rate.

Quote:

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Originally Posted by Kuntz

I'd tend to think that too, more turbulence in the radiator translates into better transporting of heat to the radiator fins. If you stir a pot of water, does it come to a boil much faster than if you just leave it sit? I live in a Dorm and can't test this. :)

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Actually if you stir a pot, it will boil slower, but it is not due to turbulence. It is because you are letting ambient air into the liquid, which cools down what you are stirring. A pot that is not being stirred, still has natural convection to spread the heat around to all the liquid quickly.

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Originally Posted by nikhsub1

I think you need to do some reading too. Step 1, reread what I wrote and what I was referring to. You asked me if I was kidding? Closed loop? Yes the assumption is a closed loop. And flow rate DOES make a difference in radiators. Please check your facts.

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Please show us a benchmark of how flowrate through a radiator affects temps in a closed system.

Quote:

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Originally Posted by 3Z3VH

Also, my sentence isn't misleading. I agree with you, they get more efficient as the delta between ambient and water temps increases. Now, when you are given a constant value as your ambient temperature, what is the only variable that will increase the delta between ambient and water temps ? That's right, the temperature of the water... meaning, the hotter the water, the more efficient the radiator will be, since the ambient is considered a constant (for the purposes of this conversation). Now read my sentence again, considering that the ambient temp is a constant.... The hotter the radiator is (due to water temps) the more efficient it is. Seems true to me !

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I knew what you meant, however when you say the hotter the rad is that could mean hot ambient with cool liquids or vice versa. No matter, we are just arguing semantics.

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Originally Posted by 3Z3VH

Please show us a benchmark of how flowrate through a radiator affects temps in a closed system.

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http://swiftnets.com/Technical/Asses...erformance.pdf

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Originally Posted by nikhsub1

I knew what you meant, however when you say the hotter the rad is that could mean hot ambient with cool liquids or vice versa. No matter, we are just arguing semantics.


http://swiftnets.com/Technical/Asses...erformance.pdf

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Except my semantics were relevant to the conversation, and yours were not.

Also, every graph in that link shows that the higher velocity of your water, the more heat gets dissipated. You'll even notice, that as the flow rate gets critically low, the heat dissipated becomes exponentially smaller. This supports my argument, not yours.

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Originally Posted by 3Z3VH

Except my semantics were relevant to the conversation, and yours were not.

Also, every graph in that link shows that the higher velocity of your water, the more heat gets dissipated. You'll even notice, that as the flow rate gets critically low, the heat dissipated becomes exponentially smaller. This supports my argument, not yours.

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Actually.

Quote:

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Originally Posted by 3Z3VH

Running the water through the radiator twice as fast, only means that you will take half the heat out of twice the volume of water... making the whole issue a wash.

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and

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Originally Posted by 3Z3VH

Basically, the difference between the two will be negligible unless you get to extremes

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is wrong. But you seem to have tried to turn the tables.

In nikhsub1 link the diff between .5 and 4gpm is about 40% increase and is hardly "negligible"

Thank you [XC] riptide, I was beginning to think I lost my mind for a second. He says that flow rates won't make a difference, I say otherwise. He then asks me for proof (as if I have no idea what I'm talking about :rolleyes: ), I provide it, then it proves my point and he says he is right and I am wrong. Wow.

My argument was that the higher the flow, the more heat a radiator dissipates. I was correct. I also stated that the hotter a radiator is, the more heat it dissipates, I am still correct, as shown by the graphs YOU presented.

Also, I said "unless you get to extremes"... as you will read from MANY sources, here and elsewhere, anything below 1.5GPM you should start worrying about how to increase flow rate... meaning 0.5GPM is an extreme.

Again, you have lost sight of the argument you were trying to make, and are now arguing semantics.

Show me proof that lower flow rates are more efficient in a radiator than higher flow rates, because you still have not done so.

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Originally Posted by 3Z3VH

Show me proof that lower flow rates are more efficient in a radiator than higher flow rates, because you still have not done so.

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There is none, higher flow rate will be more efficient (not considering pump heat to achieve this flow). When did I ever say lower flow rate was better? Please read my sig.