Watercooling

Howell

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No.

If the water could absorb the heat instantly, you could put a pan of water on the stove, and as soon as you turned on the heat, the water would boil.

Water does absorb heat energy instantly. It just takes a lot of energy to heat water to a measurable degree. Unless its tired...then its nearly impossible to get water excited.

The goal isn't to heat water. The goal is to draw heat away from a source with water. The larger the temperature differential the larger the heat transfer/time. So you want the coldest water right at the heat source all the time. The longer the water is allowed to linger the more heat it will have absorbed and the less likely it is to be the coldest.
 

Bozo

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Yeah, but he's not trying to heat water, he's trying to cool the water block.

In effect, he is trying to heat the water, with the heat from the water block.

Howell:
"The longer the water is allowed to linger the more heat it will have absorbed and the less likely it is to be the coldest. Today 04:47 PM"

Exactly! The closer the water and the water block come to the same temperature, the slower the heat transfer. The idea is to regulate the flow to get the maximum heat transfer from the water block to the water.
If the water enters the water block at 50F and leaves at 55F, thats good. If the water enters at 50F and leaves at 60F, that's better. The idea is to regulate the flow to get the maximum heat transfer while still reducing the CPU temp. At some point the temperature differential will stop climbing and the CPU temp will stop dropping. He might even need to increase the water flow.
Hopefully the water from the radiator goes to the CPU first. Otherwise the CPU would be getting warm water from the other water blocks.
 

ddrueding

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If the water enters the water block at 50F and leaves at 55F, thats good. If the water enters at 50F and leaves at 60F, that's better.

That would be the flaw in the logic right there. I don't care about the temperature of the water, just the waterblock. Try to explain your position while only describing the temperature of the waterblock, not the water.

The bigger the differential, the more heat gets transferred. Therefore I want the biggest differential all the time. The biggest differential is when the water first hits the waterblock from the radiator. The longer the water sits at the waterblock, the smaller the differential, the warmer the waterblock will be.
 

ddrueding

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Hopefully the water from the radiator goes to the CPU first. Otherwise the CPU would be getting warm water from the other water blocks.

That is right. Flow is currently as follows:

Reservoir->Pump->Radiator->CPU->GPU->Reservoir

Once my new bits arrive, it will look like this:

Reservoir->Pump->Radiator->CPU->NB->GPU->SSD->Reservoir
 

Howell

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The primary objective is to transfer the heat energy away from the source as quickly as possible. That means keeping the temperature differential as large as possible for any given point in time. If you have proof that contradicts these fundamentals of physics you could be famous.you should start wih Fourier's law of conductivity.
 

ddrueding

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Dd, have you considered branching the source into parallel circuits.

I had, but considering the really small temperature differential between what is going into the radiator and what is coming out of the radiator, it didn't seem worthwhile.

I was, however, considering branching out to more radiators in parallel. This might allow me to cool the system passively. Shame those radiators are so expensive...
 

ddrueding

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It is a great experiment. And for those who build high-end systems but don't make changes regularly, or for those who are pursuing really quiet machines, this is a way to go.
 

Bozo

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That would be the flaw in the logic right there. I don't care about the temperature of the water, just the waterblock. Try to explain your position while only describing the temperature of the waterblock, not the water.

The bigger the differential, the more heat gets transferred. Therefore I want the biggest differential all the time. The biggest differential is when the water first hits the waterblock from the radiator. The longer the water sits at the waterblock, the smaller the differential, the warmer the waterblock will be.
The reason you monitor the water temperature into and out of the water block is to see how well the water block is working. The higher the temperature difference between the incoming water and the outgoing water the more heat you are removing from the water block.
 

ddrueding

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The reason you monitor the water temperature into and out of the water block is to see how well the water block is working. The higher the temperature difference between the incoming water and the outgoing water the more heat you are removing from the water block.

Nope, the difference in temperature times the amount of water is equal to the amount of heat removed.
 

Santilli

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Ever considered mixing 50% anti-freeze 50% water? Anti-freeze is MUCH better at absorbing heat then water.
 

sdbardwick

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Ever considered mixing 50% anti-freeze 50% water? Anti-freeze is MUCH better at absorbing heat then water.
I often hear that, but nobody seems to have any evidence. Got a link? I'm not saying it isn't true, but like so many other oft repeated watercooling maxims, there is a good possibility that this one might also be false.
 

Santilli

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Just car experience. With anti-freeze the temperature on my water-goes up to 50%, very quickly.
Likewise, as soon as the load is less, it drops to 20%, or less, quickly.

Pure water, the temperature will rarely go past 40%, but, once it gets up there, it stays there, longer....
 

Howell

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http://www.koolance.com/technical/cooling101/002.html
What do all of these numbers mean in a liquid cooling system?
The above thermal conductivity shows why copper is the preferred cold plate material for cooling systems. It is extremely close to silver in performance, but only 1/6 the cost. Like most metals however, copper doesn't hold heat for very long-- it needs to be absorbed by something else.
The specific heat capacities show water to be the best liquid for holding heat. Practically, it is also the best for transferring it.
This would indicate the ideal configuration is to use copper to transfer heat from the processor, and to use water to absorb and move away the heat. Although there are many other factors involved, here you have the basic foundation of a liquid cooling system.

One thing you could do to enhance the cooling is to make use of the energy transferred during evaporation and mist the radiator with water or maybe alcohol. That would likely get the radiator below ambient temperature. IIRC.
 

sdbardwick

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Just car experience. With anti-freeze the temperature on my water-goes up to 50%, very quickly.
Likewise, as soon as the load is less, it drops to 20%, or less, quickly.

Pure water, the temperature will rarely go past 40%, but, once it gets up there, it stays there, longer....

My take is that the observed behavior indicates that the antifreeze/water mix is less efficient at cooling than 100% water (BTW running 100% water for extended times in contemporary engines is a very bad idea - corrosion/rusting accelerates). Look at the data in Howell's post regarding thermal conductivity and specific heat capacity.
The mix gets hotter more quickly due to the reduced thermal conductivity and specific heat capacity respectively. The mix's temperature reduces faster due to the lower specific heat capacity.
 
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ddrueding

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Interesting lessons learned today.

1. Don't mess with the system while it is on.

2. A leak does not automatically mean system failure.

While poking and prodding with a temperature gauge, I slightly unscrewed one of the barbs on my GPU cooler. A trickle of water began running down the back of the card and into the PCIe slot. Went over to the keyboard and chose start->shutdown, system shut down just fine.

The new waterblock and barbs arrived today, so the system is torn apart awaiting re-assembly tomorrow. I've already torn apart the z-Drive to mount the waterblock and took some pictures while it was in pieces. It seems to be composed of a pair of 250GB SSDs that each contain a pair of Indilinx controllers and a really neat backplane that feeds both SSDs to the RAID card.
 

Chewy509

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Stupid question time? Why choose water cooling, over either Peltier coolers or Phase change cooling techniques?

Peltier coolers are slient and offer very good cooling properties at the expense of electricity usage.

And Phase change cooling will get temps on the CPU down to -15C with top end equipment even when overclocking and the component(s) are under extreme load.

And the upshot, is with both you don't have to worry about burst pipes dousing water over everything.

FYI: Peltier Effect and coolers see: http://en.wikipedia.org/wiki/Thermoelectric_effect and http://en.wikipedia.org/wiki/Peltier_cooler.
 

time

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My take is that the observed behavior indicates that the antifreeze/water mix is less efficient at cooling than 100% water

Fair enough. Coolant is added to increase the boiling point of water, but more particularly, to substantially decrease the freezing point. Pressurization increase the boiling point much further.

So, with an Internal Combustion Engine, cooling capacity is increased. However, with a PC and its much lower temperature, there's no benefit and as pointed out, you may even go backwards.

How about molten sodium? I hear it's good for nuclear reactors ...
 

ddrueding

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I've read that all the dyes will eventually decompose and gum up the works, so my final configuration will be distilled water with some silver in it to stop growth.

I've decided to mount the system to the wall. Motherboard, GPU, and Z-Drive on top, with the radiator, pump, and power supply in a cabinet under the desk. Ordered the last of the parts today, hope to have them Monday.
 

Sol

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Stupid question time? Why choose water cooling, over either Peltier coolers or Phase change cooling techniques?

Peltier coolers are slient and offer very good cooling properties at the expense of electricity usage.

And Phase change cooling will get temps on the CPU down to -15C with top end equipment even when overclocking and the component(s) are under extreme load.

And the upshot, is with both you don't have to worry about burst pipes dousing water over everything.

FYI: Peltier Effect and coolers see: http://en.wikipedia.org/wiki/Thermoelectric_effect and http://en.wikipedia.org/wiki/Peltier_cooler.

Both of those solutions would be much more expensive and have the potential to cause condensation on the motherboard which is a similar worry to a leak but, IMO, harder to guard against. Phase change uses a compressor which is louder than a pump and peltiers need either major air cooling (loud) or water cooling (leak risk).
 

ddrueding

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I had considered using a peltier in combination with my CPU waterblock, but I can always do that later if I need it. The condensation is a scary thing as well.
 

Bozo

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Why don't you just mount everything ( motherboard ) in a small refrigerator and just bring out the cables you need? :grin:
 

ddrueding

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Because a refrigerator lacks the capacity to deal with the amount of heat I'm generating. Building a giant TEC-cooled enclosure with the machine in it is a neat idea though. Perhaps that is next.
 

Santilli

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I had considered using a peltier in combination with my CPU waterblock, but I can always do that later if I need it. The condensation is a scary thing as well.
Since you don't use cases, just mount the motherboard as the bottom component in a chimney, with the board upside down. Any condensation can go into a 'drip bucket'.

Peltiers are WAY cooler then water cooling;0
 
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