Phase Change

I don't really know much about phase cahnge, but I know you have to use a coolant like propane or freon. Both of these are flamable and I really don't like the idea of a flamable gas in my room. There is an alternative called r-134a that isn't flamable. I would like to know how it will perform compared to propane. Thanks.

134-a is okay, and will freeze your coolant along with the best of 'em. Not quite as cold, but it will freeze.

One question though, did you know there's more butane in your can of deodorant than you could fit in some phase change systems? Try lighting shaving cream once (over the sink). Ever see a Pop-Tart get stuck in the toaster? Just adding to your flammable fobias....I'm kindof sick that way.

Lol. Do you have any temps? I am getting a friend to show me how to build it? He just said it is a lot better than water cooling, so I am wondering about what are the temps with propane and then what are they with r134-a?

Temps for refrigeration would be impossible to guess.

You could go by boiling temps of the r-xxx you use, but even that can be changed simply by running a vacuum on the low pressure (evaporator) side of the system to get even lower still. There's heat load, coolant, capillary tube size, evaporator size, r-xxx ammount, condensor size, condenser cooling, compressor size, litterally dozens of factors to consider.
All told, you can make it difficult to keep the coolant from freezing.

I do think there's a point of diminishing returns, where the temperatures you're trying to reach are more for bragging than for overclocking, because you'll still hit the chip's limit (both in speed, and the (-)temps it'll survive long term).

Personally, I'd be happy at +10C full load.

I would be happy with 20C. Can r134-a do that? I am a real newbie here.

a properly constructed system with r-134a should easily keep your load temps under 20c, but matching cap tubes to a compressor and refredgerant can sometimes be challenging. But if you planning on going with phasechange you should try to hit a goal of about -5c full load. Just make sure you do your homework and read up alot about it.

Yeah I tihnk avg. temps for R134a are around -20c.
R134a is a waste,I use R290(propane) in all of my systems,I was weary of it at first.But now I am not at all.Refrigerants like R12 and R22 arent flammable,but they create a poisenous gas in an open flame....
I think R134a boils at around -20c or so,I am not sure.Propane boils at -43c I believe.Just search for boiling points on google.Really depends on the system you build....

Thanks for the info. I am not building this, my friend is building it for me and he was set on using propane. I am just a litte worried about it being flamable. If I were to use propane and lets say it leaked and I lit a match what would happen, cuz it is only a small amount?

I don't think there's an explosion concern. If memory serves you need 80 to 20 air propane mix to explode, and it's actually hard to make it explode.
Turn on your propane stove, and light a match a few feet away...nothing, and that's with much more gas.
You'd get a flame for a few seconds if the match were close to the stream of gas, and the fact that the system is pressurized and venting outward, no flame would go inside and make it explode. Even when the leak stopped, there's still no oxygen inside the system to support combustion.

Propane is popular in Europe where they don't have PAC committees with members like DOW chemical and the automaker's and such to push money under the noses of congressmen. This lets them sell refills for $15 a can instead of $3 bucks like propane that you can get anywhere, and service for car A/C is astronomical vs. filling your own with cheap propane.
I'll bet you thought the government did all that refrigerant control for our safety, or the environment?

Just for the record bongs are phase change coolers, too. At
least if they are working correctly.

Tecumseh said:

Just for the record bongs are phase change coolers, too. At
least if they are working correctly.

Click to expand...

Ya basically,but refrigeration systems are in a loop,and changes phase more than water does in a bong
If you want to get technical

But what exactly does that have to do with this?

aenigma said:

Ya basically,but refrigeration systems are in a loop,and changes phase more than water does in a bong
If you want to get technical

But what exactly does that have to do with this?

Click to expand...

Not Jack that I know ! In the old Freon systems you can
use propane and it's nearly as efficient. IF you are retro'ing
an old system this is the way to go.

About the bong...just wanted to broaden the discussion and
add completeness.

Tecumseh said:

Not Jack that I know ! In the old Freon systems you can
use propane and it's nearly as efficient. IF you are retro'ing
an old system this is the way to go.

About the bong...just wanted to broaden the discussion and
add completeness.

Click to expand...

Yep R290 works ok,alot better than R134a thats for sure....

ok guys here is the link to a wondeful page with boiling points for freons and lots of good stuff.i have been where you are now so i know this will help.there is not many of us out here with working freon systems that are working properly so remember this is not as easy as it looks.but with time anyone can do it. http://www.hvacwebtech.com/freons.htm#P/T Chart