Refrigeration?

Has this been done?
What are the lowest temp desireable?
Is there a limit to how cool to cool?

 

Wait so you want to put your pc in a refrigerator?

 

Lol. Not really. But being a HVAC/R tech it wouldn't be that hard to for me to build a cooling setup . Refrigerant gases to me would be better than water cooled around such delicate devices. Is cooler better? Or is there a point that it doesnt matter?

 

I never really thought about that, since you are an expert, what is the highest average cool temp for a frig?

 

That depends on refrigerants. i.e. I could built a very small system that would cool to -10 dF using 406A or 414b. I guess what I really need to know is there a cutoff point to too much cooling as in at what point does cooling stop being efficient and necessary. Obviously a refrigerant style cooling system might not be very practicat to normal use. But might be viable for bigger systems and/or ppl who over clock and such.

 

It might be useful, if you can maintain the temp of the frig around 30 C, but wont the frig gases harm the pc?

 

Now I must do the math of CtoF. But I imagine either 1 of 2 things the rfrigerant would be from coils and have no direct contact to components. I.E. no moisture.

 

So is 30c the desirable temp to run systems?

 

Ok 86.8dF to maintain. Not practical then would cooling it more be better? And how much more?

 

Well moisture from a frig can ruin a system, thats why no one has made an attempt to use frigs to cool systems. good temps for a pc normally range from 30C to 55C. but if you can maintain a constant temp without moisture, it might actually work.

 

You can get cooler, 20C should be no sweat, since that is only slightly below room temp. Condensation would be the key for me, but in general, baring condensation, you could go even lower. As a general rule of thumb electronics works better even cooler. When I worked in a cleanroom as a tech I tried liquid nitrogen (understand I was just playing around), and that was too much, but previous hitting the low point most of the stuff kept working better and better.

It would definately extend the life of your electronics. For a while I was thinking of using a monster TEC, the kind used in coolers for refrigeration. I might yet still.

If it works you might have a new product on your hands. Some guys are nuts for estitoric hardware, anything new, and refrigerant seems safer than water by a long ways to me.

 

I was thinking maybe integrating TEV with system controlled VVT. With a push pull evap coil would keep most of the moisture away then add a dehumidifyer would be A++. I might be on to somthing here. I guess I better start a mock up. I think I can use a R-22 water fountain compressor(120v) and bulid or find some suitable coils. 9/5 x dC + 32= dF. 69dF so maybe to maintain a range of 63dF to 73dF should'nt be too hard to accomplish w/o a dehumidifyer. Hmmmm

 

If you do manage to get a frig cooler runnin make sure to make me one, ill buy it

 

Sounds cool but inneficient. The difference in heat transfer rate between room temperature air and cooled air is not going to be too significant. Water cooled is definately a more effecient means to acheive that same goal.

 

Keywords you need to google are:

Phase Change Cooling
&
Cascade Cooling

It has been done to the extreme but we are talking about getting CPU's temp down to -20C and further. Go for it look around for these key words and you may even find appropiate tech specs for build and design.

 

The Peltier Junction/Thermal Electric junction is massively inefficient at this writing all though it's efficiency has dramatically improved over the last five years. The inherent problem is getting rid of the "HEAT" from the junction, larger cooling fins than are already present. One simple solution is 99% Isopropyl Alcohol/Rubbing Alcohol and a small pump and cap tube to spray the solution on the CPU heat sink (obviously a sealed system) and the boiled alcohol re-condenses in an Evaporator with the pump picking up the liquid to recirculate. When and if I get the time to get my CC RC lathe and milling machines up I have the plans to build one, only problem is that the darn chip manufactors keep coming out with faster cheaper chips. Thats my $0.02 worth

 

TECs are inefficient, but you can get them quite large, and the primary ingredient is already in abundance, low voltage high current DC. The unit I have (cost was $20) takes 12VDC at 4Amps. My thought was to pull the heat out of the case and dump it in the house.

If you ever want a truely inefficient but fun gadget, try a vortex tube. People keep trying to say it is a modified venturie tube, but it's not. It is a completely different effect. Feed a vortex tube 150PSI and you get air at 100+PSI at 100C on one end and air out the other end at 30PSI at -40C. They are used a lot in machine shops to cool the work, many materials cut better cold (or hot, depending).

 

Anytime you have a <good> cooling system condensation is a issue. It was something we fought a lot in the clean room, where we had several pieces of equipment that used chilled water. The one that gave us the most trouble was a degreaser, because all the chilled water coils were out in the open. We wound up building a thermal transfer unit that recirculated the water in the degreaser chilled water system and exchanged the temp with the house chilled water. This allowed for precision control on the degreaser chilled water temperature. It was pretty simple to build a temperature controller on that arrangement.

Dealing with condensation a better measurement than relative humidity is dew point. They are the same thing, but dew point is the temperature that water begins to condense at. While the statement that water only condenses on surfaces colder than ambient is generally true, there are exceptions, and it doesn't have to be a lot colder either. Fog is the case when air is at dew point temperature, you did mention being outside. I think most people think in terms of indoor cooling though, and 5 Degrees difference can cause condensation. People get used to their air conditioned houses, where the air is dried. Add enough cooling inside any case and condensation will be a problem, temperature and humidity being the main controlling variables.

BTW, love the avitar!

 

Thanks for the responses. My first idea was to force conditioned air in to the case. But after reasearching the subject I'm in the process of building a direct die phase changer cooler. I have it all assembled and working on the die design. I have 1 design that works well but I think with more tinkerin I can get at least a 12% improvement in temperature and heat exchange.

 

Like I said before, you might think about marketing something like that. Heat, especially in certain climates, is always a problem for certain computers.

 

is it possible you could post pics? sounds like its coming along quite well, keep it up

 

As soon as I can replace my digital camera (it's some where in the Colorado River ) I'll post some pics. And some specs. Basically I'm using a water cooler compressor,condensor coil and fan, that has been fitted into a chopped compaq presario case. The controls are of my own design using off the shelf HVAC/R controls. The die is where I'm not happy I can replicate those seen on commercial units (not too fond of) and have copied some custom home builts (that work better than the commercial ones) but I think I could do better in design and/or using other metals (not copper). I have yet to test it on a PC. Mainly cause all I have is this stupid DELL. But my intended use if for a Pen D 805 which will be my budget build. If they can get 4.1ghz on water I wonder what it'll get on phase change. Funny I can build a phase change for next to nothing but have nothing to use it on (yet). I'll keep y'all updated. PPPMD

 

This is too funny! I was actually thinking of cooling my computer by taking it outside... it's well below freezing out there now. (-6C or about 25F) It might be too cold to type though. But it is something to think about. For those of us illiterate to cooling systems and think our problems may be due to overheating... worth a try to find the culprit?

 

According to the AMD site, colder is better until you hit freezing (zero degrees centegrade). Below that the CPU is in danger of cracking because of the differential expansion rates of the silicon substrate vs. the metal circuit traces.

AMD has an AMAZING pdf white paper about all this and I wish I had the URL. I was just fascinating and I recommend everyone read it.

BTW, it's virtually impossible to freeze a running CPU because it's generating a lot of heat in a very small area. When I left mine outside, I deliberately kept it running all the time because I was worried about the chip getting too cold and cracking if I turned it off.