Pump heat - Page 2

Sled_Dog · 08-12-2002, 09:44 PM

yeah I know that is way wrong but thats what it said. files must be messed. Hmm MBM still says 95. The block is warmer as is the line at its outlet. fan back on see if it changes

ambient · 08-13-2002, 12:01 PM

here's the dl for radiate
http://www.overclockers.com/articles430/
but it is jacked and doesn't let you specifiy Vcore less than 2v
http://www.benchtest.com/calc.html
above site has a page you input data to.

bigben2k · 08-13-2002, 12:15 PM

Ok, I ran the numbers, and they say that the heat output of that CPU would be 94 Watts max, with 88% of that (expected max heat output from typical high priority burn in) being at 83 Watts.

I don't know about ya'll but me thinks this CPU is toasting.

nexxo · 08-13-2002, 02:29 PM

Look guys, we can go on forever like this.

Bigben2k: I'm NOT saying it's just convection at work here. It is about warming water expanding and displacing cooler water from the rad; this pours into the reservoir. Because the reservoir is above the waterblock in the circuit, the law of communicating vessels dictates that water coming out of the res outlet will gravitate down to the pump and then push up again toward the waterblock, as water in the tube and res try to level out. This pushes the expanding warming water in the block further upwards into the rad, and so on...

Want to test whether I'm right or not? Just move that res to the lowest point in the circuit (say, at pump level). Watch that temperature climb.

P.S. before we get on that bandwagon: I'm NOT saying it is just the law of communicating vessels at work here either; it is a combination of both.

bigben2k · 08-13-2002, 03:07 PM

Quote:

Originally posted by nexxo
Look guys, we can go on forever like this.

Bigben2k: I'm NOT saying it's just convection at work here. It is about warming water expanding and displacing cooler water from the rad; this pours into the reservoir. Because the reservoir is above the waterblock in the circuit, the law of communicating vessels dictates that water coming out of the res outlet will gravitate down to the pump and then push up again toward the waterblock, as water in the tube and res try to level out. This pushes the expanding warming water in the block further upwards into the rad, and so on...

Want to test whether I'm right or not? Just move that res to the lowest point in the circuit (say, at pump level). Watch that temperature climb.

P.S. before we get on that bandwagon: I'm NOT saying it is just the law of communicating vessels at work here either; it is a combination of both.

I think that it is only convection. Your "warm water expanding" theory doesn't hold, well... water! Water will increase in volume by about 0.2%, over a 20 deg C temp range. It's just not enough to account for any kind of flow.

As for the gravity, since the system is a closed loop, the gravity factor is non-existant, because what has to go up one side, must come down the other, thereby cancelling the gravity effect. The res could be 50 ft up, on the roof of the house, it doesn't matter. (I think/hope that this is clear to everyone already)

I agree that warm water will flow upwards though, and I think that it's been demonstrated here. Moving the res will have no effect whatsoever: the warm water enters the rad (albeit very slowly), and is cooled. Period. As long as the loop is closed, it will work.

I still maintain however that the CPU temp is very high, as the block temp indicates. The load on the CPU might not be as high as to output 85 watts though.

We'll have to wait and see the water temp readings. The block should be a few degrees hotter than the water. (and the core should be hotter than the block).

JimS · 08-13-2002, 03:22 PM

From the picture, it looks like the output from the radiator fan is causing just enough air circulation around the CPU socket to keep the system up. Probably cooling off the waterblock to some extent and making it into a makeshift heatsink. I would not bet on it running very long though. This is assuming that the radiator fan is on. If the rad. fan is off, then I have no clue.

nexxo · 08-14-2002, 01:33 PM

Quote:

by bigben2k:
I think that it is only convection. Your "warm water expanding" theory doesn't hold, well... water! Water will increase in volume by about 0.2%, over a 20 deg C temp range. It's just not enough to account for any kind of flow.

True, but only a little bit of water has to be pushed out of the rad and into the res, for water coming up the circuit to replace it, and thus maintain circulation.

Quote:

As for the gravity, since the system is a closed loop, the gravity factor is non-existant, because what has to go up one side, must come down the other, thereby cancelling the gravity effect. The res could be 50 ft up, on the roof of the house, it doesn't matter. (I think/hope that this is clear to everyone already)

Err... my point is that what goes down (from the res) must come up again (towards the block/rad). The water level in the tube will "attempt" to level itself out with the water level inside the res. You think that putting a res up high makes no difference? Explain home water tanks in the loft, and the idea behind water towers then.

(sorry, don't mean this to sound like a bitch-slapping contest...

)

bigben2k · 08-14-2002, 02:02 PM

No problem. It's only through discussion that we'll get to the bottom of this.

First off, the water heater tank: this is not a closed loop setup, because the water comes in from the city main, through the hot tank, then out to the faucet. The placement is important, because what goes out does not come back in. This is a big issue in skyscrapers, because the pressure at the bottom of a pipe (1st floor) would be tremendous (threatening the integrity of the pipe), just from the sheer weight of the water running all the way up to the top floor. That's why they use water tanks on multiple levels (that was a side note, and has nothing to do with anything!).

In this particular case, the water DOES return, as it does in a closed loop, so what goes up must come down. I will admit though that there may be a slight bit of flow induced because the hot water has a lesser density, and so the system would balance itself out by flowing in a (favorable) direction, until the density of the water on each side would be equal, but again, since the volume of water affected is so small, and the density change of that small volume may be in the order of 0.2%, this would be infinitesimal.

The other effect, where if you had a mass of hot water in the middle of a cold tank, would create a small flow where the hot water would rise to the top, but again, this is a density issue, as described above. That's convection.

As insignificant as this effect is, it does appear to work, at least sufficiently enough for the hot water to reach the rad, then be cooled.

To answer the water tower question: as I've described above, a city's waterworks is not a closed loop, where the water exiting one way is forced back in the system. The loop is broken by the drain (among other places): when you run the water, it is free to accumulate in a tub/sink, or flow right down the drain. The water that you are running will not be affected by the amount of water being drained. In a closed loop, that's not the case.

To answer the density issue: once the system is balanced, where the hottest of the water is cooled steadily by the rad, the volume of the water no longer increases: the system has reached a steady state. The amount of water being heated is the same as the amount of water being cooled, negating the volume change effect. The overall volume will change, but that'll only show up in the res as a level increase. Once the level has risen to where the system is in solid-state, there is no more expansion. That's why the volume change theory doesn't work.

Just to clarify, the water level in the res should be above the res intake: otherwise the system is not closed (which I'm assuming it is).

Skulemate · 08-14-2002, 06:49 PM

I just wanted to add something about whether or not a system is closed. In any system, "closed" or not, you're going to have a point where there's zero pressure. The only difference between an "open" system and a "closed" one is the fact that in the open system you are forcing this point to occur at a specific point in your loop, due to the presence of the resevior, and the water level in it.

Oh, and about the res on the 50 ft. high roof thing... you can get a siphon effect in any system, whether it is "open" or "closed", provided that the system is primed first... I've played around with this in my system, which is a so called open system. All you'll do is cause a spot in the elevated location with lower pressure (i.e. when the tubing rises above the piezometric head line of your system... in a "real" watersystem this can potentially cause problems).

Sled_Dog · 08-14-2002, 08:31 PM

yeah my thermal probe must be messed. Turned the pump back on and the temp went down 2 degrees. Before that I turned the fan off and ran it at full load and the temp didn't budge from 95 degrees so. Oh well new board, chip, ram will fix that

nexxo · 08-15-2002, 01:24 PM

@ bigben2k:

I think I begin to get where you're coming from. I am assuming that the res inlet is above water level in the res. The outlet of course comes out the bottom. Are you thinking of a setup where the res inlet is just below the water level in the res?

Anyway, it looks like the whole thing was academic after all. Back to pumping :sigh:

bigben2k · 08-15-2002, 01:41 PM

Quote:

Originally posted by nexxo
@ bigben2k:

I think I begin to get where you're coming from. I am assuming that the res inlet is above water level in the res. The outlet of course comes out the bottom. Are you thinking of a setup where the res inlet is just below the water level in the res?

Anyway, it looks like the whole thing was academic after all. Back to pumping :sigh:

Academic it was... oh well.

I was thinking about a setup where the res inlet and outlet were below the waterline. That's why we discussed it so extensively...

Thanks to Skulemate, I've learned a new word today: "piezometric"! Right on, Skulemate...

Sled_Dog · 08-15-2002, 01:57 PM

my inlet and outlet are both below the waterline. I don't understand what you are saying I guess. My res is filled all the way to the top and the res inlet is below that water. My next system(if I decide to spend the money) will have the inlet and outlet on equal planes(same level) both below waterline.

nexxo · 08-16-2002, 02:44 PM

OK. Your temp probe and CPU are just screwed. Tough luck, dude.

Sled_Dog · 08-16-2002, 02:47 PM

nothing wrong with the CPU and I don't care about the probe. CPU still ocs and runs perfectly.

08-12-2002, 09:44 PM	#26
Sled_Dog Cooling Savant Join Date: Jul 2001 Location: Snowyland(not Alaska) Posts: 238	yeah I know that is way wrong but thats what it said. files must be messed. Hmm MBM still says 95. The block is warmer as is the line at its outlet. fan back on see if it changes __________________ pro/chat has a website now? wow

08-13-2002, 12:01 PM	#27
ambient Cooling Savant Join Date: Jan 2002 Location: Planet Earth Posts: 312	here's the dl for radiate http://www.overclockers.com/articles430/ but it is jacked and doesn't let you specifiy Vcore less than 2v http://www.benchtest.com/calc.html above site has a page you input data to. __________________ water cooled 1.4 tbird @ 1580 143x11 vcore 1.88 vio 3.55

08-13-2002, 12:15 PM	#28
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	Ok, I ran the numbers, and they say that the heat output of that CPU would be 94 Watts max, with 88% of that (expected max heat output from typical high priority burn in) being at 83 Watts. I don't know about ya'll but me thinks this CPU is toasting. __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

08-13-2002, 02:29 PM	#29
nexxo Cooling Savant Join Date: Jul 2002 Location: Brimingham, UK Posts: 385	Look guys, we can go on forever like this. Bigben2k: I'm NOT saying it's just convection at work here. It is about warming water expanding and displacing cooler water from the rad; this pours into the reservoir. Because the reservoir is above the waterblock in the circuit, the law of communicating vessels dictates that water coming out of the res outlet will gravitate down to the pump and then push up again toward the waterblock, as water in the tube and res try to level out. This pushes the expanding warming water in the block further upwards into the rad, and so on... Want to test whether I'm right or not? Just move that res to the lowest point in the circuit (say, at pump level). Watch that temperature climb. P.S. before we get on that bandwagon: I'm NOT saying it is just the law of communicating vessels at work here either; it is a combination of both. __________________ "There is a thin line between magic and madness" Last edited by nexxo; 08-13-2002 at 02:32 PM.

08-14-2002, 02:02 PM	#33
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	No problem. It's only through discussion that we'll get to the bottom of this. First off, the water heater tank: this is not a closed loop setup, because the water comes in from the city main, through the hot tank, then out to the faucet. The placement is important, because what goes out does not come back in. This is a big issue in skyscrapers, because the pressure at the bottom of a pipe (1st floor) would be tremendous (threatening the integrity of the pipe), just from the sheer weight of the water running all the way up to the top floor. That's why they use water tanks on multiple levels (that was a side note, and has nothing to do with anything!). In this particular case, the water DOES return, as it does in a closed loop, so what goes up must come down. I will admit though that there may be a slight bit of flow induced because the hot water has a lesser density, and so the system would balance itself out by flowing in a (favorable) direction, until the density of the water on each side would be equal, but again, since the volume of water affected is so small, and the density change of that small volume may be in the order of 0.2%, this would be infinitesimal. The other effect, where if you had a mass of hot water in the middle of a cold tank, would create a small flow where the hot water would rise to the top, but again, this is a density issue, as described above. That's convection. As insignificant as this effect is, it does appear to work, at least sufficiently enough for the hot water to reach the rad, then be cooled. To answer the water tower question: as I've described above, a city's waterworks is not a closed loop, where the water exiting one way is forced back in the system. The loop is broken by the drain (among other places): when you run the water, it is free to accumulate in a tub/sink, or flow right down the drain. The water that you are running will not be affected by the amount of water being drained. In a closed loop, that's not the case. To answer the density issue: once the system is balanced, where the hottest of the water is cooled steadily by the rad, the volume of the water no longer increases: the system has reached a steady state. The amount of water being heated is the same as the amount of water being cooled, negating the volume change effect. The overall volume will change, but that'll only show up in the res as a level increase. Once the level has risen to where the system is in solid-state, there is no more expansion. That's why the volume change theory doesn't work. Just to clarify, the water level in the res should be above the res intake: otherwise the system is not closed (which I'm assuming it is). __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101 Last edited by bigben2k; 08-14-2002 at 02:07 PM.

08-13-2002, 03:22 PM	#31
JimS Cooling Savant Join Date: Jun 2001 Location: Connecticut Posts: 140	From the picture, it looks like the output from the radiator fan is causing just enough air circulation around the CPU socket to keep the system up. Probably cooling off the waterblock to some extent and making it into a makeshift heatsink. I would not bet on it running very long though. This is assuming that the radiator fan is on. If the rad. fan is off, then I have no clue.

08-14-2002, 06:49 PM	#34
Skulemate Cooling Savant Join Date: Jul 2002 Location: Toronto, Canada Posts: 381	I just wanted to add something about whether or not a system is closed. In any system, "closed" or not, you're going to have a point where there's zero pressure. The only difference between an "open" system and a "closed" one is the fact that in the open system you are forcing this point to occur at a specific point in your loop, due to the presence of the resevior, and the water level in it. Oh, and about the res on the 50 ft. high roof thing... you can get a siphon effect in any system, whether it is "open" or "closed", provided that the system is primed first... I've played around with this in my system, which is a so called open system. All you'll do is cause a spot in the elevated location with lower pressure (i.e. when the tubing rises above the piezometric head line of your system... in a "real" watersystem this can potentially cause problems). __________________ Michael E. Robbins M.A.Sc. Candidate, University of Toronto 12.1 GHz of AMD's finest (17.7 GHz total) crunching proudly for the AMDMB.com Killer Frogs SETI BOINC: Dual Opteron 246s (Iwill DK8N) \| XP2800+ (Shuttle SN41G2) \| 3x XP2400+ (ASUS A7N266-vm) SETI BOINC: 2x P4 2.8E (ASUS P4R800-vm) \| Crunching 24/7

08-14-2002, 08:31 PM	#35
Sled_Dog Cooling Savant Join Date: Jul 2001 Location: Snowyland(not Alaska) Posts: 238	yeah my thermal probe must be messed. Turned the pump back on and the temp went down 2 degrees. Before that I turned the fan off and ran it at full load and the temp didn't budge from 95 degrees so. Oh well new board, chip, ram will fix that __________________ pro/chat has a website now? wow

08-15-2002, 01:24 PM	#36
nexxo Cooling Savant Join Date: Jul 2002 Location: Brimingham, UK Posts: 385	@ bigben2k: I think I begin to get where you're coming from. I am assuming that the res inlet is above water level in the res. The outlet of course comes out the bottom. Are you thinking of a setup where the res inlet is just below the water level in the res? Anyway, it looks like the whole thing was academic after all. Back to pumping :sigh: __________________ "There is a thin line between magic and madness"

08-15-2002, 01:57 PM	#38
Sled_Dog Cooling Savant Join Date: Jul 2001 Location: Snowyland(not Alaska) Posts: 238	my inlet and outlet are both below the waterline. I don't understand what you are saying I guess. My res is filled all the way to the top and the res inlet is below that water. My next system(if I decide to spend the money) will have the inlet and outlet on equal planes(same level) both below waterline. __________________ pro/chat has a website now? wow

08-16-2002, 02:44 PM	#39
nexxo Cooling Savant Join Date: Jul 2002 Location: Brimingham, UK Posts: 385	OK. Your temp probe and CPU are just screwed. Tough luck, dude. __________________ "There is a thin line between magic and madness"

08-16-2002, 02:47 PM	#40
Sled_Dog Cooling Savant Join Date: Jul 2001 Location: Snowyland(not Alaska) Posts: 238	nothing wrong with the CPU and I don't care about the probe. CPU still ocs and runs perfectly. __________________ pro/chat has a website now? wow

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