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General Liquid/Water Cooling Discussion For discussion about Full Cooling System kits, or general cooling topics. Keep specific cooling items like pumps, radiators, etc... in their specific forums. |
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#1 |
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Following this link I've decided to let ya'll know that I will no longer recommend windshield wiper fluid as a coolant.
It's clear that this type of coolant/fluid is really not meant for indoor use: it is volatile, very toxic, flamable (to a certain extent), and that it must be kept in a sealed environment, as much as possible, even outdoors. I'm sorry if any of you have decided to go that route, based on my advice. I would advise you to switch to a glycol (ethylene or propylene), with all the precautions that these fluids require. In the mean time, I will continue to look into other coolants. Be safe! ![]() |
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#2 |
Cooling Savant
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I wouldn't read too much into this. Given the temperatures at which extreme cooling systems operate, an open system is not a realistic alternative. Extreme cooling should not be taken lightly and I'd encourage everyone to do their homework prior to beginning. However, with the right system setup, the methanol/water mixture is very tough to beat. The mixture also does not have nearly the toxicity/flammability concerns of straight methanol.
In short, yeah there are definite precautions to take, but the windshield wiper mix is about as good as it gets for operation down to -40°C. |
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#3 |
Cooling Savant
Join Date: Dec 2001
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Nough said.
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#4 |
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Join Date: Aug 2001
Location: KS
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oh crap, you werent supposed to drink it?
j/k
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#5 |
Cooling Neophyte
Join Date: Jul 2002
Location: TX
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If your making a sealed system for water chilling how do do these 2 things with it?
1. dissassemble moderately easily (to change pumps, or move it when needed) 2. Has direct contact with the cooling fluid (if it doesn't you generally won't get as good temperatures) Even if it didn't meet those 2 requirements I'd be curious how you would go about making an air tight sealed water chilled system? I'd really like to seal my system but I'd lose alot of flexibility by sealing it. (Unless there's some really great way to seal it air tight but yet be able to easily open it and close it) |
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#6 |
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Join Date: Aug 2002
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I have a gallon of straight methanol sitting on the shelf downstairs...
But the blue windshield washer fluid is purtier ![]() |
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#7 |
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Thanks to everyone for their comments.
Still, I will no longer recommend it: there are too many variables for a newbie to get into something like that. ********** Windshield wiper fluid is an EXPERT/ADVANCED solution, only for those that understand the safety precautions that are required. ********** to 000: there are many ways to seal a system. If you have an intake in your rig, and you cap it off, then you can easily refill it. Also, as I've suggested before, if you put a T at the pump inlet, and put a ball valve on it, you can let the coolant out of the system through a hole at the bottom of the case. All you have to do, is prop up your computer, and turn the valve. To answer your questions, if you're going to modify your rig, you should drain it first, and rinse it out, then you can take it apart any which way you want. I'm not sure what you mean by "direct contact". If pressure buildup is a concern, then you can add a flexible component to your res (like a balloon). To myv65: I'm not going to minimize the risk here. I know better than to go against typical industrial applications. If they condone it, then I'm not going to recommend it. (not to say that I wouldn't consider using it myself ![]() |
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#8 |
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The problem with sealing my system is that I can't seem to figure out a good way to get the evaporator inside the reservoir and be sealed (which is what I meant by direct contact, the water/antifreeze is in direct contact with the evaporator from the dehumidifier).
In my setup I have the dehumidifier evaporator inside of a plastic ice chest (which is inside a bigger styrofoam ice chest with polyurethane spray foam inbetween), with the pump in there also. So I have the tubing for the pump coming out of the top of the reservoir and I also have the evaporator's capillary tube going into the reservoir and the return tube coming out, and also the power cable for the pump. I've attempted sealing it the best I can by putting the ice chest's lid over the reservoir and stuffing some foam inbetween the lid and the reservoir (and then some 2 10lb weights on top to keep it compressed down). But I still wouldn't call it air tight, small gaps form around all the various tubes going in and coming out. I'm not sure how you would make the reservoir air tight with a dehumidifier. You could make it air tight fairly easily if maybe you were constructing the whole thing from scratch (in other words you bought a compressor and some tubing and soldered/welded the stuff together and filled it full of freon yourself). Although any air tight situation seems to mean that your evaporator is permanently where ever your going to put it (which isn't very much fun for tinkering). |
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#9 |
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I think a couple of pictures might explain better than I did above here's my setup:
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#10 |
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Here's the top of the reservoir with the lid off(without the evaporator in it)
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#11 |
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Hum... that could get complicated.
First, I like your setup. The plastic ice chest inside the styrofoam ice chest, with foam in between, that's a good idea. I've used the can stuff before: it's got some quirky limitations, but otherwise works well (i.e. it won't turn solid if it's applied thicker than 2 or 3 inches away from air). I'd consider using a silicon sealant. If you still have the lid, you should be able to fit it (with a little carving), and seal it with silicone. It might not be pretty, but it'll be safe. |
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#12 |
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Yeah I lucked out with that weird property of the foam stuff, apparently you're supposed to do it in layers if you want it thick, and I just happened to do it in layers (purely accidental) since a bottle of the stuff didn't cover as much as I thought it would (took about 4 bottles to do what's in the picture), and I bought a bottle at a time so auto layers
![]() With the sealant I'd be a bit worried about the vibration from the compressor eventually wearing away that seal (it vibrates pretty powerfully), and then not realizing it was worn away. I'm not really sure how much vapor it takes to cause you damage from methanol (I know they say in the specs, but ppm doesn't mean a whole bunch to me). I sure wish stuff like flouroinert or hydrofluoroether wasn't so expensive ($200+ a gallon is out of my range, especially since I'd need 4 gallons of it ![]() |
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#13 |
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I hear you about the vibration.
In the old days, the engineering philosophy was to stop it from vibrating. Today, it's more like "let it vibrate". If you can attach some kind of rubber gasket, then seal the gasket to the foam box, the pipes could vibrate as much as they want. You have to get a little creative. |
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#14 | |
Cooling Savant
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![]() Actually, there's a number of methods for dealing with vibration. The two most common are isolation and a tuned absorber. Isolation is nothing more than eliminating rigid structural members that come between the source and that which you seek to keep still. Conveyence of vibratory energy relies on frequency of the forcing function and natural frequency of the relevent material. If the natural frequency is well below the forcing frequency, you won't get significant transmittal. This is why you'll see rubber mounts on a lot of rotating machinery. Your compressor should be affixed to a baseplate that also holds the motor. Between the baseplate and "box", you should have generous foam pads. The foam pads decouple the baseplate from the rest of your box. The other biggie is the tuned absorber, which is really nothing more than a spring-mass system tuned to the frequency of the forcing function. The two vibrate out of phase with one another such that the energy of motion is continuously travelling between the two rather than getting out. You'll find this sort of thing in electric hair trimmers, for example, to prevent fatigue from holding what would otherwise be a gigantic joy buzzer. Best bet for you is to soften up the system as Ben mentioned. You can find weatherstrip foam at most hardware stores. Look for some nice fat profile like 1" square and put it beneath the compressor assembly. It'll have a finite life and would eventually need to be replaced, but ought to last at least a year or so. The other thing I would add on this whole topic is the concern for chemical attack. You can get sealing strips in a variety of materials that will make your system essentially air tight. Each material, however, has its own regions of susceptibility. Neoprene, for example, does not work well when chlorine is present. Places like DuPont and Parker have online chemical resistance guides that can help with material selection for sealing materials. @ Ben, I don't want you to think I am flat-out disagreeing with your assessment on windshield washer fluid. Bringing up the subject for discussion so folks understand fully what they're dealing with is an excellent idea. The main point I would make is that with proper knowledge and preparation, windshield washer fluid remains the logical choice for those that want extreme cooling. Not recommending it altogether seems a little harsh to me. I'd side more with the "understand the risks and proceed only with due caution" approach. |
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#15 |
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I think I may have found a much safer (health wise anyway) alternative that's still cheap. Is there anything bad about acetone? It seems to have very similiar properties as methanol, but it doesn't seem to be anywhere near as big as a health risk and it also has better viscosity (from what I've found so far anyhow, it's hard to find viscosity charts for cold temperatures)
You can also find it fairly easy (nail polish remover). So is there any bad properties of it? (I'm trying to figure this out, but feel free to let me know so I don't have to keep on looking) |
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#16 | |
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I agree. I have to remind myself (daily, multiple times) that there are a lot of people reading this, most of which won't care one bit about safety. As for the engineering philosophy, I'm just glad that the availability of new materials has made new options available. While I was working for the airline, some people would freak out at the sight of the Airbus 340's wings, because they visibly droop down. I have to explain to them that it's part of the new engineering, where they don't try to make the wing stiffer anymore (which adds weight), they instead work the materials so that they are utilised at the best of their properties: a wing becomes stiffer as a load is applied on it, i.e. when it's in flight. A credit to engineers ![]() |
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#17 |
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More specifically to your sealing problem, you can do better, but it'll take some work. IMHO, ideally what you would have are bulkhead fittings for the stuff that needs to cross the boundary of the ice chest. For the tubing, you place a closed-cell foam between the bulkhead fitting and wall. Then you connect your tubing to the bulkhead fitting and clamp it on each side of the wall.
For the wiring and evaporator lines, you run them through a clearance hole and then seal both ends of the hole with an RTV sealant like silicone. This stuff isn't exactly permanent, but might as well be. If the thought of encasing stuff semi-permanently in silicone isn't appealing you can also get fittings for running the electric cord through the wall and sealing it. Options abound, each with its own advantages and disadvantages. For the final lid, you should also have a closed-cell strip that you clamp down with ~5 lbf/in of seal length. Having a nice smooth surface for this strip is important. The way things are now you've got a highly variable surface from the polyurethane foam. |
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#18 | |
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I don't know the heat transfer properties of Acetone. Anyone? |
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#19 | |
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Also cracks me up when people on planes get nervous because they see the engines rolling around a little during flight. They don't realize that if things were stiffer, the reaction forces would also be significantly higher. LOL, I'm a geek, but I'm glad for the education I've got and wouldn't trade it for anything. |
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#20 |
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I'm not sure about the heat transfer properties, but I can tell you an additional sore point besides the "eating your tubes" comment from Ben. It's got a low vapor pressure meaning it'll evaporate readily if given the opportunity.
As for eating the tubes, check into those chemical resistance guides I mentioned. It'll tell you what polymers can get along with acetone and what ones can't. In the meantime, I'll check my books for any thermal data. As a pre-warning, most thermal data (viscosity, c_sub_p, k, etc.) I have is for a single temperature unless it's a common heat transfer fluid. |
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#21 | |
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He he, I know what you mean, about those engines, wavering around in flight... |
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#22 |
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I think my tubes may be ok (tygon r3603, have to check though to make sure), I'm a bit worried about whether my pump casing will be ok or not (can't remember exactly what that stuff is they use to encase it), and I'm not sure about my propylene barbs.
Would acetone affect the metal's any (aluminum & copper)? |
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#23 | |
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[edit] Isee this was already mentioned ![]() |
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#24 | |
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You could get Tygon SE-200, though, that would work. (don't ask me where you'd get it!) |
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#25 |
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Hmm yeah I see that now, might be ok with only a 33% concentration though. I'll do a little test and see if it's eating into stuff tonight (put a drop of acetone on the various plastics to see if it starts dissolving it)
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