#230072 - 07/08/2004 15:21
Water Cooling (I lost control)
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carpal tunnel
Registered: 06/10/1999
Posts: 2591
Loc: Seattle, WA, U.S.A.
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OK, so I woke up last Sunday AM and found an order confirmation on my screen. It looks like during a late-night lapse in judgement I inadverdently ordered a Tyan K8W S2875 and a pair of Opterons. Oh, well, water under the bridge. In for a penny, in for a pound.
Not only do I want to water cool this thing to reduce noise at my desk, but I would actually like to route the plumbing outdoors, to a deck next to my desk as that room is already warm. I am looking at using 2 Danger Den TDX water blocks with 1/2" tubing, but I don't have any sense of how much pump is needed to push coolant the 3 meters or so needed to get out to the deck. Any hydrodynamic experts out there or has anyone experimented with this?
A couple of other things I am thinking of:
One is to use a home-brew radiator and fan built with an automotive heater core and make my own reservoir. One other option was just to use a length of residential water heating baseboard (with some of the trim removed) and have the radiator be completely passive. Am I nuts?
I am thinking that during the winter I would want to have some sort of thermistor-controlled variable flow rate -- don't let water get so cold that it creates a condensation problem inside the room/PC. Am I nuts?
Can anyone offer comments on a 12V DC or 115V AC pump that would do the job and a speed control circuit (I am think 12V DC would be most feasible) that might work? Am I nuts?
There are lots of cooling forums out there, but I have looked at them and just don't find the commentary to be of the same quality and reliability as found here.
_________________________
Jim
'Tis the exceptional fellow who lies awake at night thinking of his successes.
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#230073 - 07/08/2004 16:55
Re: Water Cooling (I lost control)
[Re: jimhogan]
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old hand
Registered: 15/02/2002
Posts: 1049
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Well, here's my $.02. I'm a mechanical engineer, but I'm not a thermal or hydraulic specialist, so others may have more appropriate comments.
Pumps are rated by pressure and flow rate. You don't need a very heavy duty pump, because you won't need a high flow rate, and you will not be lifting the water very far (maybe just a couple of feet, if that). The horizontal run of the coolant doesn't matter (within reason, with a really long run you start to factor in pressure losses due to the run), what matters is whether you are *lifting* the water -- that means pressure is required. You are just moving water in this application, with a relatively short run and without lifiting it much (if at all).
If you are going to roll your own, I would recommend the quietest fish tank pump you can find. Get a pump for a larger fish tank, as it will probably have lines that are easily adapted to the size you will be using on your computer.
When you are dealing with cooling, the thing you want to do is dissipate *power*. Knowing how many watts your CPU(s) consumes (when overclocked) can give you an upper limit of how much heat you need to dissipate (to be conservative, assume that all the electrical power is turned into heat). Convert the watts into something you can use to size your radiator pipe, like BTU/hour.
What you want is a system that dissipates heat at at least the same rate (or faster) than the CPU generates it. In my humble opinion, since CPUs are generally just fine to +50C, there is no reason to use active cooling. If you can cool it to room temperature, that is plenty good enough. If you can keep the cooling block to room temperature, or even somewhat above, you're fine. This eliminates the need for active cooling and prevents any condensation/dew point issues.
You *will*, however, need to move coolant through the system fast enough to keep the cooling block cool. You will also need to cool the coolant, which is where the radiator business comes in.
You pretty much have 3 options for cooling the coolant: passive convection, active convection (using a fan), and some kind of refrigeration. Its really a question of surface area. Those 3 options are arranged in decreasing surface area requirement. Completely passive is just fine, doesn't require any additional power, and is silent, but it is going to require a lot more surface area than if you blow a fan over it, or if you use some kind of refrigerant.
So, for cheap, easy and silent, I would use a long length of tubing with fins on it (like the home heating radiator you suggested). To test things, stick your little CPU cooler on a bright, halogen light bulb (100W+) and measure the temperature of the coolant. You need enough radiator and fast enough flow rate to dissipate the heat.
So, that's my $.02. Cooling is a function of coolant flow rate and the size of the radiator. Of course, the heat transfer rate of the little thing you stick on the CPU is a factor, but I'm assuming this is a constant. From a practical point of view, it would be really easy to build a radiator that is "overkill" for the application. Then, the faster you pump the water, the closer to room temperature you'll be, limited only by the CPU cooler's ability to conduct heat away from the CPU.
FWIW,
Jim
Edited by TigerJimmy (07/08/2004 17:00)
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#230074 - 08/08/2004 13:24
Re: Water Cooling (I lost control)
[Re: TigerJimmy]
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carpal tunnel
Registered: 06/10/1999
Posts: 2591
Loc: Seattle, WA, U.S.A.
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Thanks.
Quote:
The horizontal run of the coolant doesn't matter (within reason, with a really long run you start to factor in pressure losses due to the run), what matters is whether you are *lifting* the water -- that means pressure is required. You are just moving water in this application, with a relatively short run and without lifiting it much (if at all).
Almost no lift at all. I didn't know at what point resistance of the hose walls would factor in, but I won't worry about it. I saw one setup that used corrugated hose -- would make bends nicely without crimping/collapsing -- but I thought that would both flex more under pressure and would present more sidewall resistance. I'm thinking of using the type of polyester cord-reinforced PVC tube used in the water system on my boat -- about a dollar per foot.
Quote:
If you are going to roll your own, I would recommend the quietest fish tank pump you can find. Get a pump for a larger fish tank, as it will probably have lines that are easily adapted to the size you will be using on your computer.
I looked at several of these, but they were all AC-powered. If I have some ambition of variable flow rate, not sure how I would govern them.
Quote:
When you are dealing with cooling, the thing you want to do is dissipate *power*. Knowing how many watts your CPU(s) consumes (when overclocked) can give you an upper limit of how much heat you need to dissipate (to be conservative, assume that all the electrical power is turned into heat). Convert the watts into something you can use to size your radiator pipe, like BTU/hour.
I won't overclock, but I have a clampmeter and a broken-out IEC power cord, so I may just put some fans on the CPUs initially, run a stress test and see how many amps I can chew up.
Quote:
What you want is a system that dissipates heat at at least the same rate (or faster) than the CPU generates it. In my humble opinion, since CPUs are generally just fine to +50C, there is no reason to use active cooling. If you can cool it to room temperature, that is plenty good enough. If you can keep the cooling block to room temperature, or even somewhat above, you're fine. This eliminates the need for active cooling and prevents any condensation/dew point issues.
Yes, I want as few moving/noisy parts as I can get away with, so if I can get by with just a pump using something like the baseboard radiator or a Zalman Resorator, that's the plan.
Even without active cooling, though, I was concerned about dew point/condensation issues. Average winter temperatiures here are pretty mild, but it can dip into 20s-30s Fahrenheit and I was concerned that if if the pump ran at a constant speed, I might start circulating coolant cold enough to create condensation. My thinking would be to slow circulation down a bit, let CPUs keep coolant warmer. There's probably a flaw in my logic there re: coolant then spends more time in the loop out of doors (getting colder).
Quote:
You *will*, however, need to move coolant through the system fast enough to keep the cooling block cool. You will also need to cool the coolant, which is where the radiator business comes in.
You pretty much have 3 options for cooling the coolant: passive convection, active convection (using a fan), and some kind of refrigeration. Its really a question of surface area. Those 3 options are arranged in decreasing surface area requirement. Completely passive is just fine, doesn't require any additional power, and is silent, but it is going to require a lot more surface area than if you blow a fan over it, or if you use some kind of refrigerant.
I am thinking that there are more reasons to go the heater core route with, say, a constant flow rate but a fan on the core that switches on and off depending on coolant temperature coming into the PC.
Quote:
So, for cheap, easy and silent, I would use a long length of tubing with fins on it (like the home heating radiator you suggested). To test things, stick your little CPU cooler on a bright, halogen light bulb (100W+) and measure the temperature of the coolant. You need enough radiator and fast enough flow rate to dissipate the heat.
So, that's my $.02. Cooling is a function of coolant flow rate and the size of the radiator. Of course, the heat transfer rate of the little thing you stick on the CPU is a factor, but I'm assuming this is a constant. From a practical point of view, it would be really easy to build a radiator that is "overkill" for the application. Then, the faster you pump the water, the closer to room temperature you'll be, limited only by the CPU cooler's ability to conduct heat away from the CPU.
If my concern about cold weather condensation is legit even with a passive system, the more I thought about it the more variables seemed to come into play -- CPU temp, coolant temp, pump speed -- if I wanted to control coolant flow in a passive system. Unless I started programming a PIC now to manage all of that, I figured I would build something that could have a really bad see-saw feedback effect -- speed pump up, slow pump down. Sooooo, I am thinking now of that heater core approach that would probably function passively during colder weather but with a big fan that would switch on when/if CPU temps hit a certain threshold.
One thing that surprises me a bit: I would have expected to see some of these water blocks have coolant temperature sensors on the block or the outlet. Haven't seen that yet.
Thanks again!
_________________________
Jim
'Tis the exceptional fellow who lies awake at night thinking of his successes.
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#230075 - 08/08/2004 15:31
Re: Water Cooling (I lost control)
[Re: jimhogan]
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carpal tunnel
Registered: 06/10/1999
Posts: 2591
Loc: Seattle, WA, U.S.A.
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Note to self: Maxim 6655/6
_________________________
Jim
'Tis the exceptional fellow who lies awake at night thinking of his successes.
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#230076 - 08/08/2004 20:28
Re: Water Cooling (I lost control)
[Re: jimhogan]
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Carpal Tunnel
Registered: 08/02/2002
Posts: 3411
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Does that room remain hot in winter? You might want to consider an inside radiator for the winter. This would prevent condensation issues, and also a potential pipe burst if you should turn the PC off and the radiator froze.
Another option to consider is radiating to another (cooler) room or basement.
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Mk2a 60GB Blue. Serial 030102962
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#230077 - 08/08/2004 20:59
Re: Water Cooling (I lost control)
[Re: genixia]
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carpal tunnel
Registered: 17/12/2000
Posts: 2665
Loc: Manteca, California
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Speaking of Basements. Isn't pressure head only a problem when, the loop is not closed, or there is a big bubble in some part of the system?
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Glenn
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#230078 - 08/08/2004 22:12
Re: Water Cooling (I lost control)
[Re: jimhogan]
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old hand
Registered: 01/10/2002
Posts: 1039
Loc: Fullerton, Calif.
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Quote:
I looked at several of these, but they were all AC-powered. If I have some ambition of variable flow rate, not sure how I would govern them.
Most of these little pump motors are either shaded pole or permanent split capacitor, and both can be speed controlled by a chopping type light dimmer (mosy any cheap dimmer is this type).
I'd put a pressure switch on the discharge and monitor pump life, these cheap little pumps just love to die.
L
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#230079 - 08/08/2004 22:42
Re: Water Cooling (I lost control)
[Re: larry818]
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carpal tunnel
Registered: 17/12/2000
Posts: 2665
Loc: Manteca, California
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An X-10 dimmer? Just curious.
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Glenn
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#230080 - 08/08/2004 22:47
Re: Water Cooling (I lost control)
[Re: jimhogan]
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carpal tunnel
Registered: 29/08/2000
Posts: 14493
Loc: Canada
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Since it's a closed loop system, I think any lift that may be done will be cancelled out by a corresponding drop on the way back in -- net effort to lift is nil in such a system with no leaks.
Cheers
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#230081 - 09/08/2004 02:19
Re: Water Cooling (I lost control)
[Re: genixia]
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carpal tunnel
Registered: 06/10/1999
Posts: 2591
Loc: Seattle, WA, U.S.A.
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Quote:
Does that room remain hot in winter? You might want to consider an inside radiator for the winter.
Maybe! Seeing as I ripped out the electic baseboard heater in this room to make room for...stuff. I see valves...lots of valves.
Quote:
This would prevent condensation issues, and also a potential pipe burst if you should turn the PC off and the radiator froze.
Subject to a reality check, I hoped to put enough antifreeze in the mix to keep it moving through the mild Seattle winters...
Thinking about it...I'm betting...if I take some effort to insulated the tubing inside my "office" that the issue of condensation inside the PC itself will be zilch if I keep reasonable airflow through it. Boat liver I have been, I should know more about this!
Quote:
Another option to consider is radiating to another (cooler) room or basement.
Condo-minimum. I'm glad I have the deck!!
_________________________
Jim
'Tis the exceptional fellow who lies awake at night thinking of his successes.
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#230082 - 09/08/2004 02:26
Re: Water Cooling (I lost control)
[Re: gbeer]
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carpal tunnel
Registered: 06/10/1999
Posts: 2591
Loc: Seattle, WA, U.S.A.
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Quote:
An X-10 dimmer? Just curious.
Ha! I am actually sitting here tonight setting up a mini-ATX system to run BigSister, MisterHouse and ZoneMinder. I can see it now: thermistor on desktop CPU sends "I'm too cold!" temperature SNMP trap to BigSister...MisterHouse sends X10 "slow-down!" message to aquarium pump.
Rube, we hardly knew ye!
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Jim
'Tis the exceptional fellow who lies awake at night thinking of his successes.
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#230083 - 09/08/2004 02:33
Re: Water Cooling (I lost control)
[Re: jimhogan]
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Carpal Tunnel
Registered: 08/02/2002
Posts: 3411
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Quote:
Condo-minimum. I'm glad I have the deck!!
Hmm. Maybe your upstairs neighbors want underfloor heating?
_________________________
Mk2a 60GB Blue. Serial 030102962
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#230084 - 09/08/2004 17:41
Re: Water Cooling (I lost control)
[Re: jimhogan]
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old hand
Registered: 15/02/2002
Posts: 1049
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I think you should just have the radiator inside. Then you don't have to worry about freezing or condensation, or anything else. Simpler. If you get the CPU to something close to room temperature, that should be plenty good enough.
Jim
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#230085 - 09/08/2004 18:03
Re: Water Cooling (I lost control)
[Re: jimhogan]
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Carpal Tunnel
Registered: 08/02/2002
Posts: 3411
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Another thought - what lighting do you use in that room? I'm guessing that the heat from a PC wont be more than that of 2 lightbulbs. Maybe halogen bulbs could help mitigate your heat problem to the point where radiating your PC there won't be an issue.
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Mk2a 60GB Blue. Serial 030102962
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#230086 - 10/08/2004 02:24
Re: Water Cooling (I lost control)
[Re: gbeer]
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old hand
Registered: 01/10/2002
Posts: 1039
Loc: Fullerton, Calif.
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Quote:
An X-10 dimmer? Just curious.
Yep, any X-10 dimmer should be ok. Acutally, the only dimmer that would cause problems are those huge old wirewound reostat type, which are hard to find and expensive these days.
L
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#230087 - 27/12/2004 19:07
Re: Water Cooling (I lost control)
[Re: TigerJimmy]
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carpal tunnel
Registered: 06/10/1999
Posts: 2591
Loc: Seattle, WA, U.S.A.
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Well,
It is not finished, but all of this talk of AMD CPUs got me to pull a couple pictures off my camera. I did go with a radiator out on my deck, currently running a water/isopropyl mix.
The pics are on the big side (kept them that way for a detail-interested friend)
Inside the Computer
Out on the Deck
I have a couple quarts of methanol and am going to flush and refill with H2O/methanol and add some fittings at that time. I found a stopcock to put on the drain, I am making an in-line temp sensor and am looking to somehow get one of these.
Right now I am hard pressed to get either CPU over 35C with cpuburn, but I expect I will hook those radiator fans up before summer. The Eheim 1260 pump moves lots of water and is quiet (mounted it on double rubber dampers which I am going to improve further still....)
Just install FC3 x86_64 last week. All is fast and very quiet.
_________________________
Jim
'Tis the exceptional fellow who lies awake at night thinking of his successes.
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#230088 - 27/12/2004 19:22
Re: Water Cooling (I lost control)
[Re: jimhogan]
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pooh-bah
Registered: 31/08/1999
Posts: 1649
Loc: San Carlos, CA
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Wow, how much have you been able to overclock with that setup or are you just using it to eliminate noise?
Edited by mcomb (27/12/2004 19:24)
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#230089 - 27/12/2004 19:47
Re: Water Cooling (I lost control)
[Re: mcomb]
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carpal tunnel
Registered: 06/10/1999
Posts: 2591
Loc: Seattle, WA, U.S.A.
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Quote:
or are you just using it to eliminate noise?
Mostly to have a dual-CPU box that doesn't howl. Running grip/cdparanoia/lame convinced me that having a dual-CPU box was worthwhile, but a dual PIII I used to have sounded like a 747 on takeoff.
The Tyan K8W 2875 didn't look very overclock-friendly, but that was OK. My first K8W died and needed RMA, so I will be careful anyhow. Maybe once I have all of the sensor/shutdown improvements done, I can experiment!
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Jim
'Tis the exceptional fellow who lies awake at night thinking of his successes.
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#230090 - 27/12/2004 20:03
Re: Water Cooling (I lost control)
[Re: jimhogan]
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carpal tunnel
Registered: 08/03/2000
Posts: 12338
Loc: Sterling, VA
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I must congratulate you. I've always admired water cooled systems, but never had the courage to do it myself. Yours is extra impressive!  My friend tried going with a water cooling system with the very first machine he ever built. Not a great idea. Apparently the machine was very loud, which is not good considering it was water cooled. He used it for almost half an hour before the smoke started to appear 
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Matt
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#230091 - 28/12/2004 16:45
Re: Water Cooling (I lost control)
[Re: jimhogan]
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addict
Registered: 24/08/1999
Posts: 564
Loc: TX
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Jim,
Could you let us know what parts you used for this?
I too have always wanted a home brewed water cooled system but have never ahd the confidence to try it.
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the chewtoy for the dog of Life
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#230092 - 28/12/2004 17:41
Re: Water Cooling (I lost control)
[Re: jimhogan]
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old hand
Registered: 15/02/2002
Posts: 1049
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Nice Job!
How do you keep the disk drives quiet?
Jim
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#230093 - 28/12/2004 19:09
Re: Water Cooling (I lost control)
[Re: Dignan]
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carpal tunnel
Registered: 06/10/1999
Posts: 2591
Loc: Seattle, WA, U.S.A.
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Dignan Quote:
Yours is extra impressive!
Why thanks. Not done yet!
ashmoore:Quote:
Could you let us know what parts you used for this?
Let's see:
CPU water blocks: Dangen Den TDX
GPU water block: Danger Den Maze4
radiator: Danger Den double (with a pair of 120mm fans)
pump: Eheim 1260 from ???
reservoir: a kitchen storage bin from Storables (pretty generic, but nice lid)
hose: 1/2-inch ID polyester-reinforced PVC from West Marine (and a bit of 3/4" and 1" ID)
reservoir fittings: too-expensive Marelon through-hull fittings from West Marine (bedded with polyurethane caulk).
clamps: stainless hose clamps from hardware and marine stores
pump/radiator enclosure: from IKEA, doubles as end table
PC case: Lian-Li PC60 (nice open spot to make holes for the hose bibs)
Various other nylon and brass fittings: marine stores, Lowe's and ???
Eheim pump isolation mounts from frozencpu.com
DIY #2 pump isolation mounts (big-ass rubber stoppers): Lowe's
Impressed with the fit and finish on the Danger Den stuff. I used the fiber-reinfornced hose because of tight bend radii between CPUs/GPU and am glad I did. Went all 1/2" ID for more flow. Did not trust plastic hose clamps so went stainless.
TigerJimmy Quote:
How do you keep the disk drives quiet?
No special care yet. They are a pair of Seagate 200GB SATA on a 3Ware controller. Seem darned quiet. The case is one that I had previously enhanced with some sound-deadening butyl sheet and some lead-foil-foam insulating sheet, so that helps, too
(edit: fixed Eheim typo)
Edited by jimhogan (28/12/2004 23:01)
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Jim
'Tis the exceptional fellow who lies awake at night thinking of his successes.
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#230094 - 28/12/2004 19:24
Re: Water Cooling (I lost control)
[Re: jimhogan]
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addict
Registered: 24/08/1999
Posts: 564
Loc: TX
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Thanks Jim, I am starting on my new PC project in january and I want it super quiet. One new water cooled system coming right up, I just hope it looks as cool as yours
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