Please find holes in these ideas

EbolaZaire

n00b
Joined
Aug 16, 2004
Messages
40
I've been toying around with the idea of actively cooling the water in the water-cooled setup that I'm going to build, there's several ways I could go about cooling the water but let's assume for the moment that I have something cooling the water to such a point that condensation would be present on the lines.

Idea 1 - What if I used some material other than tygon as the tubing? Suppose there was some sort of unobtanium tubing that had a heat conductance of 0, that is to say that the tubing conducts no heat. Wouldn't this prevent condensation from building up on the tubing as the tubing wouldn't "sweat" at all?
Does such unobtanium tubing exist, and if it does exist could one use it for an application such as this? I figure there must be something like this or else it'd be impossible to run liquid nitrogen through a tube without heat transfer destroying the tube via expansion of the liquid nitrogen.


Idea 2 - What if I completely sealed the computer case so that there was only one hole through which air could enter and only one hole through which air could exit with a moisture trap placed inline? Suppose that such a task of sealing was feasible (which I'm not too certain of at the moment) and I essentially had a closed loop environment where all the air entering the case was air that had exited the case and passed through the moisture trap.
The moisture trap I have in mind is like those used in hospitals; a cylinder filled with moisture trapping beads (in the OR version the beads turn from blue to red as they become hydrated and can be recharged by microwaving them).
So in this situation I would run the air loop until all the moisture had been removed and then I'd start the computer with the chilled water in normal tygon tubes. As there'd be no moisture in the loop (and any moisture that entered the system would hypothetically be removed via the moisture trap) would there be any concern with condensation forming on the tubes of the water loop? Would any condensation that did form be sucked up into the moisture trap before it dripped off the line and wrecked havoc on the electronics?


Or am I going about this all wrong? Is there a simple way to run a chilled water system that I've overlooked? Or is it just an effort in futility to run a water chilled setup because of better alternatives/complexity and danger?

What was conveyed to me is that a chilled water setup is not worth the effort because you have to insulate the lines against condensation as well as the blocks and that I'd be better off running peltiers between the water blocks and then just insulating them.

How does one go about insulating a peltier, is there a diagram/mspaint image that would make the simplicity of such a task self-evident? Are you insulating the borders of the interface between the peltier and the chip just around the edges or do you need a layer of insulation between the peltier and the chip which seems stupid to me...?
 
Your ideas on the tubing and the moisture are all valid in theory. However, there is no material with a thermal conductivity of zero, and you'd be hard-pressed to find an alternative to a polymer tubing such as Tygon without resorting to something insanely expensive. As far as the moisture trap goes, the cost and difficulty of implementation are probably going to make it not worth the effort.
Sometimes the simplest ideas are in fact the best. Go to Lowe's, get some pipe insulation, and wrap those tubes :D
 
So all I'd need to do is wrap the tubes? Wouldn't there be condensation on the blocks as well, or will the heat that they're conducting take care of any condensation problems on the blocks?
 
I have been thinking about making a water chiller setup using an inexpensive window A/C unit.

I have done alot of research on the subject and the performance of such a system is far better than peltier equiped waterblocks. Also the price is far cheaper at about 80-90 dollars for a small A/C unit and the use of all your normal W/C gear, assuming you have a setup already and the skillz/tools to mod the A/C unit.

The only way I have seen chilled water used when coolant temps were well below ambient requires insulating the lines and the W/B's and M/B-V/C.

I recently had an idea I thought would be fun to try, although many power users might not like it for it will make hardware changes to the system more difficult. I still have a few questions myself about how well it would work and if it is even possible without ruining hardware, but here goes.

I would like to seal the entire case practically air tight. This would still require insulation of the lines leading up to the case. Once the lines enter the case insulation would no longer be required and in addition to the usual water blocks on CPU/GPU/NB install a single 120mm size heatercore with fan inside the case to act as an evaporator and circulate cold air inside the case to cool components not in contact with the waterblocks such as mosfets, memory, powersupply, etc. Dessicant could be placed inside the case to handle existing moisture and any small, probably inevitable outside air leaks.

I'm not sure how the optical drives would be able to handle this situation since they would obliously be exposed to the ambient outside air and have thier metal casing inside the case be in contact with the cool air most likley causing condensation inside the drives themselves. This could be remedied by using a USB2 or Firewire drive and Alcohol 120%.

Also depending on how cool the case will get your case itself will probably sweat.

All things considered it should be doable, however I'm far away from having either the time or the money to start such a project. :( Rest assured some form of this idea will be my next cooling mod.
 
It depends on how far below ambient your temps are. In most cases, you have to insulate the block and tubes. Sometimes you have to insulate the bottom of the motherboard (underneath the CPU) too.
 
I was actually replying to the guy above you. As far a water chiller goes, I think they're a great idea. I built a direct die phase change for myself, but you can't beat a chiller for versatility (you can cool both your video card and CPU with it) It's not that hard to insulate properly. Just use that armalite stuff on the hoses. The tricky part is the CPU/Heatsink area, but it should be easier to insulate a waterblock than a direct die evaporator.
I assure you just insulating the hoses and waterblock is far easier than making an air tight case. :)
 
adding dessicant beads in-line will drop the dew point of water a lot. Not sure if you can reach the -20C mark though...I will check my steam tables at work tomorrow. I think you will have to achieve <5% RH to get the dew point that low, and that won't be feasible.
 
Well, I was really close. Ambient air at 70F and 1 atm has a dew point of -20C at 4% relative humidity. That's tough to achieve with dessicant typically designed for 10-40% RH. Also, note that thin layers of water lubricate moving metal parts and extreme dehydration has led to problems on space stations without water lubrication...
 
If you're using an AC unit to chill your water - just divert a bit of the AC air through your case. AC air by definition is very dry, and should prevent condensation very nicely. As for getting your case completely enclosed - your problem zone will always be your powersupply. Unless you spend $250 on a watercooled PS you cannot just close the case.
 
whitewale said:
If you're using an AC unit to chill your water - just divert a bit of the AC air through your case. AC air by definition is very dry, and should prevent condensation very nicely. As for getting your case completely enclosed - your problem zone will always be your powersupply. Unless you spend $250 on a watercooled PS you cannot just close the case.
A/C air is actually 100% saturated with water. Only when air conditioned air heats up is it considered "dry." Also, no one uses AC air to chill water, allowing a small amount of AC air to be diverted. The whole evaporator is immersed in the cooling water, so there is no "air" to divert.
 
Oops it seems I have hijacked this thread. Oh well it seemed like an appropriate subject title for my ideas.

To clarify things I doubt even with -20c coolant temps after cooling the GPU and CPU that the case temp in a sealed case would get below 0c. Also I live in the desert southwest so relative humidity averages 25%-35% to start with.

Also the idea of sealing the case and cooling the air inside would for the purpose of providing cooling air to all the components that would be difficult to cool with chilled waterblocks, such as system memory, power supply, mosfets, etc.
 
A/C air is actually 100% saturated with water
Yep, at the temperature of the cooling elements, something like -20 C. What means the dew point is way lower then your average room air.
 
You may have also overlooked the other problem with -20c water based coolant - how do you prevent it from freezing? - your choices, for water are limited...theres anti-freeze mixture (technically it should be called anti-boil as thats its primary purpose)...or theres a mixture such as methanol.

Anti-freeze mixture would need to be at least 50/50 - resulting in a very sludgy, extremely hard to pump, significantly poorer thermal property coolant. Flow rates will be right down, less than a 1/4 of your original rate.....the heat absorption properties are also severely hindered. Anti-freeze/water combinations make a terrible coolant.

Methanol 50/50 mixture has much better thermal properties - not too far from just water alone....it also has a very high flow rate. But it has some major draw backs

-Its flammable, even in a 50/50 mixture the whole liquid is flammable.
-It evaporates very easily, it has a very high viscosity - requiring very good seals
-You may need alternative tubing to PVC as i think it may attack/permeate throught it
-Finally, its toxic - it permeates the skin easily, the fumes given off are toxic.

Thats the night mare with a water chiller - until recently its either been anti-boil...or methanol. However the best solution is a preflurocarbon liquid such as inertx - thermal properties close to that of water, totally inert (no corrosion), -90c freezing points.....only problem is its very expensive - 550ml costs £50 - about $90
 
How do you relate evaporation with viscosity? A high viscosity fluid (one that resists flowing) would seem to reduce leaks, not increase them. Did you mean LOW viscosity?
 
froudeg said:
Anti-freeze mixture would need to be at least 50/50 - resulting in a very sludgy, extremely hard to pump, significantly poorer thermal property coolant. Flow rates will be right down, less than a 1/4 of your original rate.....the heat absorption properties are also severely hindered. Anti-freeze/water combinations make a terrible coolant.
50/50 EG:water is not sludgy or extremely hard to pump by any stretch of the imagination. 50/50 has about double the viscosity and about 80% of the heat capacity of water, but it's freezing point has been depressed to -37F. Flow rates won't drop to 1/4 original, especially not in 0.5" tubing. They may be more like 60% design. Antifreeze/water is a great coolant.

froudeg said:
-It evaporates very easily, it has a very high viscosity - requiring very good seals
Methanol is fairly inviscid. For the record, surface tension properties (not viscosity) determines "leakability" in liquids. For gasses, it's molecular weight.
 
froudeg said:
You may have also overlooked the other problem with -20c water based coolant - how do you prevent it from freezing? - your choices, for water are limited...theres anti-freeze mixture (technically it should be called anti-boil as thats its primary purpose)...or theres a mixture such as methanol.

Actually Ethylene Glycol or your common "Antifreeze" primary purpose is antifreeze not anti-boil. Ethylene Glycol does not raise the boiling point of water. The pressure at which the coolant is under is what raises the boiling point. For each PSI the system is raised, the boiling point goes up 3 degree F. Thus a 15PSI system would have a boiling point of 257 F or 125C@ sea level.

A 50/50 mix of Ethylene Glycol and water would yield a -34F or -36C antifreeze protection. It also provides corrosion protection. Up to a 70/30 mix can be used for even colder purposes. It also would not be sludgy or "hard to pump". If that were the case it would not be used in automobiles or industrial purposes.

Also the post about A/C being "100% saturated" Where did you get that information? Just curious because the basic theory on air conditioning "removes humidity". Ever see a car in the hot summer dripping water from underneath it? That is water removed from the incoming hot, humid summer air. Also home HVAC's do the same thing. Now I know it doesn't remove 100% of RH but air coming out past an evaporator has significantly less humidity than the air going in. Removing humidity is a by product of air conditioning.
 
whitewale said:
If you're using an AC unit to chill your water - just divert a bit of the AC air through your case. AC air by definition is very dry, and should prevent condensation very nicely. As for getting your case completely enclosed - your problem zone will always be your powersupply. Unless you spend $250 on a watercooled PS you cannot just close the case.


Just house the power supply outside of the main box. $250 saved.
 
100% saturated means that the cold air leaving the cooler has as much water in it as that temperature of air can hold. The air leaving the evaporator is in equilbrium with the water dripping out the bottom.

A dehumidifier incorporates a heater (it's actually the condenser). So it works like this:

Air 85% Humid 70F -----> cooler ---> 100% humid 35F -----> heater -----> 25% humid 75F

Removing humidity isn't a "byproduct" of air conditioning. Cooling air increases the relative humidity of the air. It is when that air heats back up without a new source of water near by that the relative humidity drops. Hotter air has the capacity to hold more water, but without more water to evaporate, humidity gets lower.
 
froudeg said:
You may have also overlooked the other problem with -20c water based coolant - how do you prevent it from freezing? - your choices, for water are limited...theres anti-freeze mixture (technically it should be called anti-boil as thats its primary purpose)...or theres a mixture such as methanol.
Ethyl aclohol can work. It's thermal properties and viscosity aren't as good as methanol, but it isn't toxic, and has better thermal properties than freakin' Ethylene Glycol, and it is cheap and readily avaliable (albeit with additives in most states).

If I were using a sub-zero chiller, I would use ethyl. Methanol is toxic, too much of a risk to be handling.
 
You could fill the system with Everclear, and install a tap in the reserve for those late night gaming sessions...
 
Use regular pipe insulation on your lines. It will be all right, just take your time sealing the ends. As for the residue condensation I've got your ticket. I use Chemtronics KonForm SR from http://www.action-electronics.com It's a silicon based spray-on application just for electronic's. I used simular products in the Air Force. B-52's @ 50,000 ft = frozen black boxes. It''s about $25 for a 10 oz. spray can. 1 can will spray down all your parts, just tape up the contact's (use dielectric grease on the contacts). I have a computer mounted in a deep freezer thats been running for over a year now. I use 50/50 anti-freeze and water with a DangerDen electric pump (around $75). It works great. Don't use a submersable pump as they generate heat.
 
EbolaZaire said:
I've been toying around with the idea of actively cooling the water in the water-cooled setup that I'm going to build, there's several ways I could go about cooling the water but let's assume for the moment that I have something cooling the water to such a point that condensation would be present on the lines.

Idea 1 - What if I used some material other than tygon as the tubing? Suppose there was some sort of unobtanium tubing that had a heat conductance of 0, that is to say that the tubing conducts no heat. Wouldn't this prevent condensation from building up on the tubing as the tubing wouldn't "sweat" at all?
Does such unobtanium tubing exist, and if it does exist could one use it for an application such as this? I figure there must be something like this or else it'd be impossible to run liquid nitrogen through a tube without heat transfer destroying the tube via expansion of the liquid nitrogen.


Idea 2 - What if I completely sealed the computer case so that there was only one hole through which air could enter and only one hole through which air could exit with a moisture trap placed inline? Suppose that such a task of sealing was feasible (which I'm not too certain of at the moment) and I essentially had a closed loop environment where all the air entering the case was air that had exited the case and passed through the moisture trap.
The moisture trap I have in mind is like those used in hospitals; a cylinder filled with moisture trapping beads (in the OR version the beads turn from blue to red as they become hydrated and can be recharged by microwaving them).
So in this situation I would run the air loop until all the moisture had been removed and then I'd start the computer with the chilled water in normal tygon tubes. As there'd be no moisture in the loop (and any moisture that entered the system would hypothetically be removed via the moisture trap) would there be any concern with condensation forming on the tubes of the water loop? Would any condensation that did form be sucked up into the moisture trap before it dripped off the line and wrecked havoc on the electronics?


Or am I going about this all wrong? Is there a simple way to run a chilled water system that I've overlooked? Or is it just an effort in futility to run a water chilled setup because of better alternatives/complexity and danger?

What was conveyed to me is that a chilled water setup is not worth the effort because you have to insulate the lines against condensation as well as the blocks and that I'd be better off running peltiers between the water blocks and then just insulating them.

How does one go about insulating a peltier, is there a diagram/mspaint image that would make the simplicity of such a task self-evident? Are you insulating the borders of the interface between the peltier and the chip just around the edges or do you need a layer of insulation between the peltier and the chip which seems stupid to me...?



Here...just actively cool the water with the AC unit blowing directly into the case, that way the air temperature inside the case would be lower than the water temperature in the tubing...see, no sweat.
 
I just registered to post a note on this subject since a few people seem to be heading into dangerous territory.

Based on the little I can remember due to alcohol killing off brain cells, the last thing you want to do is make your PC case a low humidty zone.

If you drop the humidty to very low relative values in the case then you are running much much greater risks of static electricity. I think the only viable solution is lagging the cold spots (pipes and blocks) and getting the heat out the case. You do not want very low relative humidities (or very high ones) around electronics.... :eek:
 
peteb said:
I just registered to post a note on this subject since a few people seem to be heading into dangerous territory.

Based on the little I can remember due to alcohol killing off brain cells, the last thing you want to do is make your PC case a low humidty zone.

If you drop the humidty to very low relative values in the case then you are running much much greater risks of static electricity. I think the only viable solution is lagging the cold spots (pipes and blocks) and getting the heat out the case. You do not want very low relative humidities (or very high ones) around electronics.... :eek:


I don't think static electricity is going to be a problem inside a PC case, unless you go in there and rub everything with pieces of carpet. Static charges do build up more easily in arid environments, but they are not caused by it.
 
zer0signal667 said:
I don't think static electricity is going to be a problem inside a PC case, unless you go in there and rub everything with pieces of carpet. Static charges do build up more easily in arid environments, but they are not caused by it.
Well, and not only that, but Methanol and Ethanol are polar enough like water to transmit charge from location to location. No static potential build up unless you are pumping something completely non-polar like gasoline (ethanol-free gas, of course).
 
zer0signal667 said:
I don't think static electricity is going to be a problem inside a PC case, unless you go in there and rub everything with pieces of carpet. Static charges do build up more easily in arid environments, but they are not caused by it.

So those fans spinning in the PSU, GPU and case, optical drives spinning discs of plastic in plastic trays and of course people's taste to mod previously earthed/shielded steel cases with nice static friendly acrylic windows aren't a potential source of static...?
 
thrashd said:
You could fill the system with Everclear, and install a tap in the reserve for those late night gaming sessions...
All kidding aside, Everclear would be a great, cheap solution for 99% Ethyl, but it is regulated in many states. For example, it is banned in California.

Now, if you make a run to Tijuana, like I did in my fraternity days for our special punch (aka, Red Death), well, you could pick some up. ;)

Seriously, methanol is nasty, toxic shit if you don't know what you are doing. It can be absorbed through the skin and actually make you blind with enough exposure, making it hard to operate clockgen and CPU-Z. Please avoid unless you have proper training and precautions. :eek: And I have never filled my watercooling system without some spillage, which is why I always do it outside of my case and in the bathtub.
 
peteb said:
So those fans spinning in the PSU, GPU and case, optical drives spinning discs of plastic in plastic trays and of course people's taste to mod previously earthed/shielded steel cases with nice static friendly acrylic windows aren't a potential source of static...?
plastic spinning vs. air does build up static...but not much really. Helicopters neet to worry about static build up, but not 60mm fans. Understand that "static electricity" is only dangerous if 1. you have a method of building it AND 2. You don't have a method of dissapating it.

For example, walking across the floor in wool socks, your body's kinetic motion is changed into electrical potential on your body. No wires or anything ground you, so you don't have any way of dissapating charge until you touch something that does (a grounded PC for instance)

A moving non-polar liquid also converts kinetic energy into static (a potential exists between, say, the rad and the waterblock) and without grounding both, the charge will build until it can spark to a ground point.

So what does an acrylic wall do? pretty much nothing to build static. It is grounded on all edges and doesn't move. What do fans do? Pretty much nothing; they too are bonded to a metal fan armature and like I mentioned already, air/plastic doesn't really build charge.
 
SuperCricket, I and some other GhettoLanparty members built a crazy computer for QuakeCon. We dealt with many of the issues you were talking about and ended up with an incredably complex, hard to maintain beast of a machine.

An airconditonder actively cools a dexcool water solution which is pumped through some water blocks with peltiers underneath them. Motherboard and most of the cooling lines float in mineral oil which prevents condensation. The rest of the tubes are insulated with average pipe insulation. The crazy thing is... it works, and it works well. SC is till running that beast as his main machine today.

fishtank_final1.jpg
 
That "unobtainium" that you were talking about using to move such liquids as nitrogen, etc i believe are all vacum-sealed. a pipe inside another pipe, with a vacum between them. the inner pipe then carries the liquid and cannot transfer the heat (or lack there of) bc there is no medium for it to go thru. not sure if that helps :confused: good luck with whatever you end up doing with this project of yours!
 
_drk_ said:
]awesomeness ensued, ghettolanparty for life!

yeah, till he left the AC off, and it got to 180degrees and water was sprouting everywhere... ;)

huzzah for ghettolan! i've been twice, might go on the 18th
 
Back
Top