New to phase-change

[yngndrw]

Hey,
Well first off, I’m totally new to phase-change cooling so my experience is only the hours of looking up resources on the internet. A little about me: My name is Andrew, I’m 17 and in college in the UK studying Physics, Computing, ICT, and Electronics.

I would like to get into phase-change on a hobby basis, but I’m unsure where exactly to start. I thought a small unloaded phase-change system would be a nice place to start, and then I could move onto cooling some old PC using direct die methods, and then maybe even building a 24/7 phase-change cooler for my main rig when I get more experienced.

So I set to work finding out about the basics of phase-change, and then moved onto ways that I could source parts, so I set off using my good old friend, Google. I found many suppliers, but the main problem that I found is sourcing the gas it's self.

I have noticed that the gas R134a is quite east to get hold of, as it's used in car A/C systems. However, from looking around the internet, I think R22 would be easiest for me to use, as it can get nice temperatures, and it doesn’t matter which oil you use it with. So my first question is do you think that R22 would be a good gas for me to start with ?

Also, I have noticed in some places that licences for handling refrigerants are needed. So if somebody could go through the implications of these licences and how they would affect me sourcing and using gasses such as R22, then that would be great.

Safety, an important subject. Now I am not planning on looking into cascaded systems until I have some good experience with phase-change, however I would like to know what would happen if one of my joints was not up to standard on say the liquid line of a single stage system, would the pressure just make it leak all over me, or would it blow up and take my face off ? :x :stick:

Something that I have seen very little on is gas recovery, I was wondering if there is a cheap way of doing this instead of having to pay for expensive equipment, as my budget is not massive.

Umm I think that just about covers everything I wanted to ask for now ..

Thanks in advance. :)

[Evil_Spork]

im relativly new to phsae change but ill give you a start.

r22 would be a good idea.

recovering gas: use a vacuum pump with a recovery chamber(thats not the proper term i dont think, but you get the idea.)

too much pressure? the compressor will fail-safe shut off for you! most at 400psi, they will kick off, so anything breaking a seal or exploding.. i doubt it!

best advice i can give is to get GOOD braze. it will make your life SOOOO much easier being a noob to brazing. i have a helluva time using cheap braze. aint easy.

phase change is very fun and not too hard! :)
you did your basic homework, so expect to get many more and more helpful responces.

welcome to XS too!

[yngndrw]

Thanks for the help and welcome. :)

Would I need to buy a special recovery chamber, or would it be acceptable to just make one out of a copper tank with a valve on ? Also is it acceptable to just let out the gas in the gauge set and charging pipes, or is there some special way to empty these ?

Ah and before I forget, I have found a local store where I can get cheap filter / dryers, however they say that they are for R134a, would it be okay to use R22 on these or is there something that is specificly for R134a in them ?

[jinu117]

Thanks for the help and welcome. :)

Would I need to buy a special recovery chamber, or would it be acceptable to just make one out of a copper tank with a valve on ? Also is it acceptable to just let out the gas in the gauge set and charging pipes, or is there some special way to empty these ?

Ah and before I forget, I have found a local store where I can get cheap filter / dryers, however they say that they are for R134a, would it be okay to use R22 on these or is there something that is specificly for R134a in them ?

Get a recovery machine, recovery tank. Do it the right way :)

[yngndrw]

Well I just had a look at some recovery machines online and I cant afford the kind of prices that they are, however i have just noticed this (http://www.xtremesystems.org/forums/showthread.php?t=70652&highlight=recovery) thread which has helped that until I can afford a proper recovery machine. :)

Any ideas on the other questions ?

[chilly1]

OK There is a thing called a recovery bag. It is a large bag and covers the part of the law called passive recover from nonworking appliances, but it still needs to be reused or brought into a shop to be moved into a larger tank..

[yngndrw]

Ah okay, i've been looking around these forums more about recovery and seen some useful stuff, however i'm not too sure what exactly should be done with the refrigerant after it's been collected. Can it just be taken to a refrigeration place and they will remove it ? Also does anybody know a refrigeration shop in the northwest of the UK (Southport / Preston area, maybe Liverpool or Manchester area also) who would be willing to help me out with this ?

Also what are the requirements of getting refrigerants in the UK ? Is there some kind of licence that I need like in the US ? If so how would I go about getting this and where could I then source gases like R22 here ?

And any idea on my filter / dryers question in post #3 ?

Thanks.

[jinu117]

Not sure in UK but in US, you pay them to dispose of recovered gas. (I've seen one place that buys "dirty" gas but not sure how it works...) I would suggest getting a recovery tank and do disposal at one shot if you can. Would be cheaper. Recovery tank can hold so much (in terms of single stage) really that you probably won't worry about having to dispose it for quite some time. Check e-bay for recovery machines. Got mine under $300. That two compressor method might work good too. Only thing I would worry about is the pulling compressor will have so much moisture and what not (hopefully not acid) in them over time that recovered gas will be totally not reusable.

[yngndrw]

Ah okay, thanks for the heads up on that. Does anybody know about the UK specific stuff though ? Including what licences I need to have.

[targ]

there is a licence for the 'better' gasses, but i beleive that r134a, r22 and r290 can be obtained without it.

but if anyone knows better lmk :p:

targ

[gkiing]

OK There is a thing called a recovery bag. It is a large bag and covers the part of the law called passive recover from nonworking appliances, but it still needs to be reused or brought into a shop to be moved into a larger tank..

Yes.. another method is to pull the refrigerant out and through a charcoal canister, where it is absorbed. You would be surprised how much they can hold.

[yngndrw]

Oh right, how would the charcoal canister then be disposed of ? Is the refrigerant stored in it reusable or is it absorbed by the charcoal ?

targ: Yea I PM'd johann about sourcing refrigerant in the UK before and he said that the licensing is abit vague currently over here, but some refrigerants can be just bought over the counter. He suggested the company Dean&Wood if that helps anybody else. :)

[epion2985]

Yes.. another method is to pull the refrigerant out and through a charcoal canister, where it is absorbed. You would be surprised how much they can hold.

hmmm :cool: