Cooling a CPU, or a GPU.

[Straight_Man]

The funny thing about cooling a CPU too much, is the metals get less conductive unless you run more wattage though the CPU to excite the conductor metals and make them more conductive because they are at ideal temp. Heat them too much, the conductive metal traces melt, heat them too little, they do not conduct well and you get slower electron flow-- to a degree. So, each CPU has an ideal temp operating range because of the metals and the ability of the non-conductive insulating materials to not conduct, and those materails have good operating temp ranges also.

Thrax's article on putting a computer in a very efficient cooler shows something interesting-- you can oc more that way because the cooling is so effective that the insulation materials are kept cold, and even the lowest temp melting materials do not melt while the conductive materials are run at ideal inner conductive trace temps for ideal conductivity. The bath was so effective that the computer could be OC'd more-- I do not know if he tried to see how much he could OC the computer, but the bath effect plus a cooling of bath material woudl have given the best results possibly for pure OCing.

Water cooling has limits mostly due to dew point of surroundign material and propagation of water molecules through the tubing causing condensation, but the biggest casue fo condensation in a water cooling system is contact of humid or damp air against cold things causing a localized dew point effect-- water droplets appear to cather on tube, but most moisture is coming from surrounding damp air, not the coolant flowing in the block.

So, how do you get past this???

Here's an idea--- take your blocks, insulate them except for your contact surface.

Encapsulate the metal cooling core in nylon, tyvek, or for a lower temp difference cooling, even liquid electrical tape, EXCEPT for the contact surface, and insulate all the INCOMING tubes to each block also. For REAL extreme cooling, you get to insulate ALL of the tubes. Now you have air against surfaces that are not cold, much less condensation, but the contact surface is cold. Ceramique will not conduct much water at all.

To control, you need a circuit that senses external CPU temp, and maintains it in a range by controlling the coolant temp so things neither get too cold in CPU nor too hot. A 12 V control circuit can be used, to flip a switch for a compressor. AC control cirucits use about 24 volts, a closed 24 volt circuit could also be used, but the temp sensors for computers that are commonly available use 12 V or lower typically as you get good thermal to voltage level responses, or inverse resistance effects, in the 7-14 V range. (Thermistors used for fans respond in this voltage flow range, inversely, and most thermal sense devices can work in this range also).

I'll give you a couple ideas-- My Prescott best likes a 60 C internal temp, for whatever reason. At 68 C it is about 90-93% efficient. So, we need to keep CPU CORE in the 58-62 C range ideally. You can do two things to cool-- secondary cooling, or primary cooling. Secondary cooling always is inefficient versus primary (direct contact) cooling. Thrax's bath proved that. Period. Excellent point made, well done experiment.

So, how do we get more primary cooling?? By doing pinpoint, direct contact applied cooling at the things that heat up, guaged to the cooling demand of those things. so, temp reactive cooling is needed, and if you want to cool everything, you need pinpoint zonal cooling. More flow of cold against hot cools more, lower temp flow cools more. So, what if we were to use zoned flow control and overall temp control of a cooling system, insulate piping to keep the surronding atmosphere from warming the coolant in the pipe, and also to prevent condensation as much as possible???

The combo of the three is what we want. Flow control (more pinpoint than the computer coolant systems now have, using temp change feedback and flow control), coolant temp control, using temp feedback circuits to control cooling and zone flows to demand based on temp rise control, PLUS direct pinpoint uninsulated contact points with insulation of all the rest except the compressor or vacuum pump (which needs to be Externally EXOTHERMIC and needs to have drainage and evaporation below it) as you will get some condensation around it ought to let us get a more effective cooling system.

Make sense??? If yes, let's discuss howto. With a cold fluid flow cooling system in mind.

[MediaMan]

What John_D is saying in a nutshell is to have a water cooling system that reacts based on temperature on die (or at the source that needs to be cooled.) This could be a programmable system much like your thermostat in your home. You could set the "ideal" temperature.

Interesting idea.

The challenges with present watercooling/peltier systems is that they are "on" or "off". The simpler the circuit; the less expensive the entire unit is. Also the size factor.

To have a system that reacts to temperature you would have to have some sort of setup similar to the normal fridge. When the temperature reaches a certain point the pump kicks in and lowers it. The problem is space. You could end up with a second case housing the entire cooling unit.

The system would also be time reactive to a point without peltier assistance. If it were only water cooled then there would be the time elapsed from the first point in time where the sensor on the processor sends a signal asking for more cooling...to the time where the system could "cool" the fluid down and circulate the cooler fluid to the processor. This would obviously be longer than a minute.

A peltier device with on/off control may provide the more immediate response until the system cooled the fluid.

The processor thermistor/sensor sends the signal that it needs more cooling. The peltier turns on and provides an immediate response until such time that a sensor in the fluid line registered that the fluid was cool enough to do the rest of the job. At that time the peltier would turn off.

The peltier and fluid temps could be programmable as to when they turned on/off. That way you don't have the peltier cooling "too much" before it turns off and, vice versa, the fluid getting "too cold" before the cooling pumps should turn off.



I sitll would like to see if a cube of Space Shuttle tile (Silica/Ceramic) would be a good heatsink. Problem is...the cost of prodution is so high. $1000 to $4000 for a single tile. Unknown how big a tile is at that price range and how many heatsinks it would make. But if a $1000 piece of tile could be cut into 10 heatsink cubes..that's $100 USD a piece.

Imagine...a heatsink that looks like a sugar cube strapped to the socket. No cooling fan required.

Now where's Thrax to shoot my theory down? :)

[Missileman]

Sorry to throw the proverbial monkey wrench on your party MM, but shuttle tiles do not conduct heat at all. They are a heat shield. They block heat transfer to the shuttles internal structures. When heat gets through - well we know what happened.

[TheBaron]

well you could use it as some form of superinsulation between different parts of your case. it'd still help i'd think

[Missileman]

Possible, but to insulate in this instance I would think being in close contact to an irregular surface would be a prerequisite. Shuttle tiles are like rigid bricks. They are very hard and very brittle. Machining them to fit would be dang near impossible.

I didn't work directly on the shuttle, but I have been in the VAB several times and have handled pieces of tiles.

I would think that using a silicone based rubber cement would work best. We used to use something we called "Red Death" on the missile launchers to protect cable points, Blast surfaces and such. It would protect the metals from melting when hit by the missile exhaust during launches. We called it "Red Death" because if anybody opened a can of it anywhere in the building, everybody would have some on their clothes by the end of the day. Any stain from this stuff was forever. It mixed like a 2 part epoxy, applied like rubber cement, and set to a dense rubber consistency. It would hug the surface and not conduct heat either.

[MediaMan]

Well

If there's anyone who would know about thermal heat shields it would be you Missleman. You're right about the the tiles. I got caught up in that demo of handling a tile while its core was still red hot. Got my physics backwards when it came to using it as a heat dissapating device.

I keep coming back to the problem of condensation. If you have something cold in a warm enviroment eventually there's going to be condensation. Without insulating the surrounding areas in a gunky mess of silicon or other such similar material...there is going to be the potential for problems. (By "cold" I mean near to the point of freezing.)

Hmmm....

Help me out here. Am I right in thinking that fluid that has a lower boiling point would be more efficient at carrying away heat providing that fluid eventually had some place to dissipate the heat to?

EG: A mercury filled system.

Or should I go back to school and take a few refresher chem and physics classes?

[csimon]

mercury is an excellent fluid to use theoretically but it's not practical. It is expensive ...clings to the tubing enough to hamper flow ...and is a health hazard.

Still ...the concepts are layed out in John's original post and it could either fly or take an alternate route ...but it is workable.

Interesting concept John_D and thanks for the explanation MM!!

[Missileman]

Well the biggest thing is the condensation point of the air. It might be good to look at lowering the humidity inside the case.

People in Arizona would have a lot less condensation trouble than us in Florida. The high amount of moisture in the air makes condensation on almost anything even cool. Our humidity is near 100% all the time and that's with a temp in the 90's.

When I was living at White Sands it was considered humid at 18% humidty. Never saw a drop of condensation while there. Even on the car air conditioners.

It might be an easier approach to the problem by removing the airs moisture.

We used to keep moisture out of Radar domes and the like to prevent arcing by filling them with a dry inert gas like nitrogen.

Dry air would work good enough in this instance. Maybe a de-humidifier on the air intake.

Just a thought for your perusal.

[MediaMan]

Well a PC case is a very porous object. I wonder if a mini-dehumidifier would do any good plus using an inert gas is out for same reason. Don't know if many airtight PC cases on the market. :)

The question stands. Is there a fluid readiliy available and affordable (and also not a bio-hazard) that has a lower boiling point than water? Fluid additives such as Red Line Oil's Water Wetter are debatable as to their effectiveness.

Glycol?

(like this discussion has NEVER taken place before. ;D )

[Missileman]

Your right about the "holey" nature of PC Cases, but one thing that comes to mind is what the military does for chemical/bio protection. They use positive air pressure to keep agents out. All that requires is that most of the holes be plugged and you keep more air going in than coming out so you maintain a slightly higher internal pressure. This would keep the moisture from getting in to the case. The inert gas couldn't be done, but positive pressure might be pulled off. Especially if all the components were being water cooled so airflow wouldn't actually be demanded. You might have to off board the PSU, but that wouldn't be hard to do.

Just thinking :beer:

[Thrax]

What about closed loop ethanol? It evaporates at room temperature, but there's no evaporation space, so methinks it would condense back into a liquid immediately.

[MediaMan]

What about closed loop ethanol?

spark BOOM[

Or we'd have a buncha drunk Short-Medians because they finally figured out they could use their watercooling setup as a still.

[Thrax]

As fun as the opticool immersion system was, the problem is that opticool fluid is too viscous to be used in a looped system (It's an HCFC, a thicker one.. See below). Its cooling properties are pretty good, but water is better in the sence that it wouldn't clog up your pump.

I'm trying to think of various fluids that cool rapidly, toxic fluids have been included too:

Ethanol (Toxic)
Amonia (Toxic)
R12 Refrigerant (Non-toxic, non-flammable, non-corrosive)
R11 Refrigerant (Non-toxic, non-flammable, non-corrosive)
R22 Refrigerant (This one is specifically designed for compact cooling units) (Non-toxic, non-flammable, non-corrosive)

And any non-toxic synthetic HCFC might be applicable.

But really, closed-loop Ethanol is no more dangerous than running a skyy vodka cooling bong, or a micro-droplet vodka evaporative unit.

[Missileman]

This needs further investigation :)

Use your computer for as an "alternate fuel" source producer.

We could market it like folding@home. Use the excess heat produced by folding/SETI to ease the local fuel/alcohol shortage.

We could make up and sell kits. We will be bigger than M$.

Who's in?

MM do you look good in Bill Gates glasses?

[MediaMan]

Ethylene Glycol closed loop would only allow for a lower freezing point to be attained. EG: A 30% mixture with water would mean the mixture would freeze at 2 degrees F or -16 C.

Pretty good for keeping fluid viscous at a colder temperature but think of the frost.

[MediaMan]

MM do you look good in Bill Gates glasses?

How do I respond to that? lol.

You're the rocket scientist here. Don't you have a gizmo kicking around that you put into a rocket to cool the circuitry? I know you probably do...knowing you'd want it quiet too so it doesn't drown out the rocket motors.

/me applies for government grant program for a research fund.

[Thrax]

Ethylene glycol is toxic, and has the unfortunate property of being an epidermally absorptive neurotoxin.

[MediaMan]

/me senses wild googling

[Thrax]

No, it's not.

I had to research HCFCs and anti-coagulants for my submersion project. :)

I had to find something that wouldn't kill me. ;D

[MediaMan]

And ethanol couldn't? ;D

Okay. lowest cost per unit of cooling is a stamped heatsink. The typical chunk o metal. The highest is watercooling and/or heatpipe based.

Any chilled watercooling setup runs the risk of condensation dependant upon the temperature. The cheapest form of a waterblock is naked machined metal.

What about reducing the overall size of the metal waterblock and encasing it within a good insulator of at least 1 cm thick? The only exposed metal would be what was in contact with the processor core.

[mmonnin]

Then you could rub some non-conductive goo all over the socket like some phase change systems require.

[Thrax]

You'd have to neoprene the socket center and board underside, and you'd have to smear dialectic grease in the socket.

There's something very cool working to the surface in this thread. hmm.

[MediaMan]

What I'm trying to ignore is the sheer amount of grease. We all know that you can goop up a waterblock into gloppy mess to keep condenstation in check.

But who wants the mess?

So what's the thinest material that insulates against the cold extremely well? Neoprene "could" be a possibility. Better suited for the hoses.

What's a plastic material that, say, the waterblock could be dipped into to form a thicker barrier? The amount of grease could then be kept to near thermal paste amounts.

/me starting to cook in his room due to 2 other PCs churning away on benchmarks.

[Thrax]

Plastic chills easily, and could form water condensate almost as quickly as the metal could.

[MediaMan]

Brainfart!

Okay...we get a waterblock...that technology has been taken care of. Anyone here work with insulating materials. Specfically vats o' insulating type stuff?

/me marvels at his own stunning grasp of technical jargon.

[Thrax]

Wool. ;D

//EDIT:

Silicate, maybe? That's an anti-condensate...

[MediaMan]

Plastic chills easily, and could form water condensate almost as quickly as the metal could.

I"m not saying plastic...but what material can be shaped around a waterblock or cut to have the waterblock fit inside? The waterblock would simply have to be custom made to have a sugar cube sized protusion on the bottom. That would be what would come in contact with the processor core. The insulating material would be flush with that.


Thrax?

wool?



EDIT/

Silicate. Now we are back to the space shuttle tile talk. Plus its known to produce sandy debris like sanding a piece of wood. And HIGHLY expensive. But we are onto something.


EDIT EDIT/

Think Man...think! Insulating material that is thin and can be machined. Two halves: top and bottom. Bottom has a square hole to receive the CPU contact plate which is also machined onto the metal waterblock as a "bump". Top has hole(s) to allow for the hoses. The two are screwed together with a silicon rubber seal between. No mess. Small tube of dielectric grease supplied in kit.

IDEA copyright Thrax and MM 2004.

[Thrax]

Whoa.. Instead of an insulation material to encase the block, what if the encasing was just a thin channel of air between plastic and the block, and all moisture condensed in there and was channeled away via a tube to an evaporative reservoir?

[MediaMan]

See above.

Proper condensation requires more evaporation/condenstation space than a tiny channel. The "waterdom" idea has more legs. Err..."blocksleeve"?

[Thrax]

My idea in a picture!

The red part is where water would condense and drain off.

Draw yours for me, MM.

[MediaMan]

hmm...Interesting.


The waterblock would be machined with a protusion. That protusion would then be flush with the bottom of the insulating package which would come in a top half and bottom half. The seal between the two would be a rubber/silicon gasket and the cross section is shown thusly.

[MediaMan]

Thrax?

So you've thought of a water jacket concept. Have I got it right? An outside condensation jacket to assist with cooling the inner core which itself is a waterblock with its own in/out feed?

[Thrax]

The water jacket itself I think would mainly deal with condensate.

The block would have to be designed with an ultra-slick coating. Teflon maybe.

When condensate formed on the block, it would immediately bead and drain down the water channel into runoff tubes which simply drain into a small reservoir which is free to let water evaporate. Or hell, it could have a small dehumidifer built into it which would accelerate the evaporation process.

The water condensation jacket would allow the block to condensate all it wanted without harming components.

[mmonnin]

You have to remember the motherboard might be verticle so the water wont run towards the motherboard but it might rather drip on your video card.

[Thrax]

Aye, which makes it even easier to drain. Because then all one must do is make the structure of the block such that it slopes off to the sides in spots where water could pool. Mind you that the shell would encompass the WHOLE block and drain to that valve. It would be sealed with silicone at the in/outlets, and it would be sealed with a temperature-resistant material where it came up against the core-contact. Basically, a hermetically-sealed shell around everything but the contact.

All water would be downhill.

[mmonnin]

You have to make it so that the water wouldnt drip at the left corner. That sharp edge could make it deattach from the surface. IT would be better off to have something on the left and right to drop off of or gather.

[MediaMan]

So Thrax and I have very similar ideas. He proposes to have the waterblock within a container of sorts. The dead airspace prevents the condensation from getting to the components. This "jacket" also acts like a channel for that moisture to accumulate and run off.

I, however, proposed that the jacket be made of a material with a higher thermal insulating value. The jacket/container would a) prevent moisture from getting to the surrounding components. While the waterblock itself may get cold...the insulating barrier would prevent that cold from every reaching the visible surface.

Much like wrapping the waterblock in neoprene as an example. The fact that the container is an insulator would actually make the waterblock more efficient. (a very small % more efficient but more efficient nonetheless).

Actually...the dead airspace around Thrax's waterblock would aid in efficiency as well.

The two could be easily blended. My original design had the waterblock fitting into the jacket with no airspace. Adding a standoff design to the design would give the channels/dead airspace required by Thrax's design. The jacket would be made in two halves and the inner surface could be coated with Teflon.

The inner waterblock would have the raised processor core surface. That would fit into a hole at on the bottom half of the container. That hole on the inner surface would have a slight raised lip (the same "height" as the standoffs for the rest of the waterblock.)

The hole and waterblock raised core surface would be mated for size thus a tight fit. Simply apply a small bead of silicon around that hole on the inner top surface and when the waterblock slides in...squish and thus a seal.

Same again with the two halves...a gasket would be better. Four screws holds the two halves together and a threaded drain hole on 2 of the sides provides for draining at either orientation.

Now who here knows of a material that is a very good insulator, can be machined via a programmable router and is fairly cost effective? (No space shuttle tiles here)

The cost of the waterblock essentially does not change. The technology is proven. It wouldn't have to be as big or as thick either. Only enough to be durable against the pressure of the clip and stand up to the force of the hose nipple assembly over time.

[Thrax]

Good brainstorming MM!

It's a pity we're a country away. ;D


//EDIT:

To see if I have this right, you're basically thinking of taking a standard water block, then encasing it in a shell comprised of two halves?

As in, you set the block in the bottom half, seal it properly and affix it to the board. Then you bring the other half down on top of the block, seal it, and wrench it down to form the seal?

[MediaMan]

To see if I have this right, you're basically thinking of taking a standard water block, then encasing it in a shell comprised of two halves?

Bang on. The inner side to the two halves would have round standoffs (5mm. in diameter). At least four per half. 6 would be better. and two on each inner "side". This would provide for your airspace and a firm seat for the inner waterblock.


As in, you set the block in the bottom half, seal it properly and affix it to the board. Then you bring the other half down on top of the block, seal it, and wrench it down to form the seal?

Could do it that way but it woud be handier to assemble the unit out of the PC case. Four screws through the unit to hold it together. This may present a problem though four mounting. The most cost effective way would be to have the four screws holding the unit together double as the mounting screws.

That in itself is a problem. You want more torque on the screws to hold the two halves together but not as much torque through the PCB. It would probably be better to go with an eight screw pattern. The four corners would align to the mounting holes in the mobo. Those would be our pressure screws for adjusting waterblock to PCB/Processor core.

The other four screws could be Alan keyed screws inset (not on the corners) for holding the waterblock jacket together. It would probably be better to use hex head bolts with a locking washer.


EDIT: Okay...Thrax and I have done our job. Whose the material expert here?

EDIT EDIT: DAMN If I had access to an Autocad driven machining router I could have a prototype made out of Aluminum within a couple of hours. It'd be a simple job..really.

My neighbour is a machinist...maybe I could...hmmm.

/me thinks of ordering a waterblock...hell...custom design that too.

[Thrax]

I was thinking mostly of a double-step installation akin to the mounting of the SLK-947.

Flush hex nuts would be most adequate to make a firm seal, I agree.

[MediaMan]

I think it would be better to torque the two halves together in your hand rather than mounting it on the motherboard then getting into an awkward area to do that.

Quick release hoses? Or good ol' slide on the tube and use a collar? I think the latter would be more watertight and cheaper.

Putting it all together outside of the case would make changing a processor easier and attaching hoses easier.



EDIT:

Okay...machining the waterblock is easy. Two 3" square chunks of copper 1 inch thick. Piece one: Side A: machine down the surface leaving a postage stamp sized "bump" equal to the thickness of the container jacket plus the height of the standoff. Hell...you could do it as a circle...makes for easier maching in later steps.

Piece one Side B: router a "S" channel for the water flow.

Piece two Side B: mirror of the "S" channel. Piece two side B: Drill in/out holes at either end of the "S" channel and tap them for the hose nipples to screw into. Apply machine sealant grease and torque in the nipples.

Weld the two halves together and buff whole unit and finish the heatsink contact area. Waterblock is done.

The two halves would be mirrors of each other. Side A would get a square (or round) hole equal to the waterblock postage stamp contact area. Side B would get two holes of sufficient diameter to accommodate the nipples.

You could get fancy and tap those holes to screw in a threaded collar. A metal Slide a metal sleeve over the hose followed by a gasket. Attach hose with crush collar for watertight-ed-ness. <---whoa...that's a new word.

Anyway slide gasket and metal sleeve over nipple assembly and screw hand tight.

Unit is now watertight. The only exposed surface of the waterblock is the postage stamp sized core area which get's cold as it should do.

[Thrax]

I think you'd be better off using standard barbs and hoseclamps. It's cheaper AND more effective, which you can't beat.

But as for your waterblock's interior, you must remember that the more turbulent the flow is, the more effective it is at dissipating heat. You might recall Swiftech's diamond pin matrix on the interior of their blocks, which is one of the most effective cooling interiors in the industry.

I understand the ease of an S-channel, but something a little more advanced, lending itself to a turbulent flow (More surface area too) would be keen.

[MediaMan]

So ya want turbulence do ya?

I looked at the Swiftech pin pattern and I don't think it's a matter of turbulence. It's a matter of maximum surface area. Heat comes up through the base and goes into all those pins. All those pins are surrounded by fluid so there is a heckuva lot more surface area for dissipating the heat.

Cheap Solution: Fine bit router drill to cut a checkerboard patter into one half of the waterblock. Like a tic-tac-toe box except a lot more of them. Surface area to fluid is thus increased.

Not so cheap solution.

The two halves are router'd out to form a box. One half has fins tacked onto the inner side. Heat transfers up the fins and this has even more surface area to fluid.

[Thrax]

Let me put it this way:

Imagine that heat is a water-soluble powder. Which gets the powder mixed into the water faster:

Sitting there, or being stirred (turbulence)?

We all know that surface area helps in shedding heat from the sink, however now you have to contend with the dynamics of a fluid arriving in a finite amount, upon which you must rely to carry heat away. Instead of an unlimited volume of ever-circulating air, you need to maximize the amount of heat taken away per cubic centimetre of water. That takes turbulence.

[MediaMan]

Okay...that makes sense.

Swiftech's waterblock design seems to be a variation of their pin heatsink. It's like they encased the pin heatsink. Makes sense for production technology as the equipment/design exists already.

I think turbulence as churning river water. I keep forgetting to downscale it to low flow rates. :)

Hmmm...low flow but still able to "churn" up the water and have maximum surface area...and be able to be routered out.

"S" channel = Minimum effectiveness.

"Checkboard" pattern = better effectiveness

What about a waffle style? Fluid is force up then down then up and so on.
Cheaper to machine than mounting pins individually or tack welding fins? The waffle pattern could be at a 45 degree angle to the square of the waterblock. Fluid enters at a "corner" then broadens out to center and then narrows back to outlet. Double churning effect?

[Thrax]

What about an expensive combination of Swiftech's diamond pin matrix, and dtek's spiral channeling?

[MediaMan]

Well hell,

If ya got money to burn then sure. ANYTHING is possible. I'm thinking cost effective here as you know us modder types. We'll bitch about the cost of anything...but usually end up spending 3 x as much. ;D

[Thrax]

I was keeping that very "3x as much" concept in mind. ;D

We might as well admit it to ourselves. :D

[edcentric]

There are a bunch of solvents that are not too flamable that are possible to use. There are a bunch of thin oils also. The question is how do you want the system to run. Do you want phase change at the CPU or not?

I saw the ultimate phase change cooling system at HP once. The took a big RISC chip and removed the heat spreader. Then they took an old inkjet plotter print head, as I recall it had 120x240 jets. The print head and the chip were almost exactly the same size. They figured out how much heat was generated at each point in the CPU. Then they set the print head to shoot micro drops of water at each location so that the water just evaported when the next droplet hit. They were able to keep the actual die temp 102C under any load. I wanted to see them do it with alcohol and run cooler.

If you used a "water cooling" system with a fluid that had a low boiling point then you could use the phase change to absorb the heat, return the vapor, condense it and repeat. This would remove heat much more efficently that water cooling. These don't need to be refrigeration systems. You could do it without compresors and such if you selected a liquid that boiled at 80-100F.

What is wrong with Pelts? They can be water cooled, there is no cold surface exposed that isn't in contact with the CPU, you can use water to dump the excess heat and the are easy to control. Ok, so they are expensive and power hogs. Do you want everything at once?

I would love to bring home a couple of Vortec tubes and hook them to my compressed air system in the basement. Blow very cold air against the CPU, vent the hot side out of the case. Loud as hell but cool.

[Thrax]

Ah, you're talking about direct-die evaporative cooling. A DIYer, whose name and project I've forgotten, did that a while back. I think he did it with a Barton, if anyone wants to combine "Barton" and "Direct die" in google.

The problem with pelts is condensation and frost. You actually have to contend with ice on your motherboard.

[MediaMan]

Thrax,

Crude first rendering of what I was thinking for the inner waterblock.

[Thrax]

Hmmm... A very intriguing design. Simple interior, yet water would be sloshing around like crazy.

/me grins

Just remember that the barbs should be pointing in opposite directions from one another, to facilitate avoiding kinks in the tubing.

Bloody hell, if we actually made something of this, we could actually market it as "The first waterblock specifically designed for chilled-water applications!" or somesuch. :D

[mmonnin]

What would be great for cooling is hacing fins like thermal rights SLK HSs. Make the water flow across all those fins. That or something like swiftech has for their HSs. The coils. That has a lot of surface area and would create a lot of turbulence if the solution was forced thru the coils.

Neither of those solutions could be done in one step tho and this cost a lot more. I was just trying to apply the best of air cooling to the interior of a water block.

[Thrax]

I'm thinking though that maybe having such thin fins on a waterblock would create significant back pressure?

[mmonnin]

A decent pump would be in order for the Swifty style block.

[edcentric]

Fins do help heat transfer. The size of the fin is dictated by the thermal properties of the working fluid. Air=large fins, water=very small fins. If you tooled the inside of the flow passages in a pattern like a knurl it would be fine. In industrial power plants finned tubing has fins that are only ~0.025" tall.
Turbulance helps heat transfer, and eat power. You need to be careful. You also want the coldest water at the outside edges, and the warmest in the hotest area. This is called counterflow and it will increase the total heat transfer.
You could also look at making the contact face out of silver, no bigger than needed and only 3mm thick. Then make the block out of stainless steel. It has very poor heat transfer, it would help cut you losses. It would be easy to solder the two together.