##choosing##components##
 

Hello All...I'm new here:D

How do I choose the components I need to make a Phase Change System...????

If I choose to use R50((methane) assuming it's easy to get) as a refrigerant,would I need to match it with a suitably rated compressor..?? What are the rules..?


Are all compressors the same..?? If I took one out of a fridge- flushed and cleaned the old refrigerant out- used it to build a phase change cpu cooler - can I then load it(system)with any refrigerant I want..??

It seems to me the temperature you get is dependant mainly on the type of refrigerant you use and the design of the evaporator head...As long as the system being built can handle the refrigerants reqirements you should reach the temp. it's rated for..!(true OR false) IS IT POSSIBLE TO REACH -100 C OR LOWER using R50:shrug:

Re: ##choosing##components##
 

ok for one you won't be able to use r50 unless you build a cascade system.so move on to a easyer refridgerant like r290 r134a r404.
something that a single stage compressor can handle.

on a single compressor i would say -45 to -50 will be the best you can hope to obtain in reason.
now if you really wanted to it is possible to build a cascading system that uses r50and yes it will go way below -100f... -258f i believe ...but to begin i would say start of small system.

check out these places
http://phase-change.com/
http://www.overclockers.com/

Thanks Bowman1964

I've read alot about phase change,just asking questions to clarify what I don't know...

Read alot of posts you have made in other forums(BOWMAN)..followed links to other sites concerning phase change/compressors/freezers etc etc.... I've got the skill to "braze" "solder" "Weld" so I'm not worried on that score....just need the knowledge to bring together all the components needed for the system I want to build.

A cascade system - does this mean its a very high pressure system..? IS IT POSSIBLE TO BUILD ONE...HAS ANYONE BUILT ONE?:shrug: :D

Check these links out, they are great.
http://oberon.ark.com/~airekool/rb1.htm
http://www.howstuffworks.com/refrigerator.html

Cascade system uses one system to cool the condenser of the other.To put it simple, it lowers overall pressure on the system being cooled, to lower evaporating pressure/temperature.But a cascade system using a low boiling point refrigerant, cools the condneser so you may condense the refrigerant at respectable temperatures.For instance if you were using a refrigerant that condensed at 500psi at 75f, you could cool the condenser to -20f and condense it at a much lower pressure.I don't know the exact numbers, as I do not have a P/T chart or a phase diagram as of now.

Oh yeah, I have built a couple cascade systems, and plan on building another one shortly.

Good luck :)

Thanks aenigma :) for the input..

Would you or anyone know of any industrial refrigeration system that uses a cascade system...I need brand names/model number if possible


Or where to price up ready made cascade systems:D :shrug:

Well I believe some cryogenic freezers use an autocascade system(1 compressor 2 refrigerants 2 evaporators and 2 condensers).But I wouldn't count on finding a cascade system, have to build it yourself if you really want one.

mmm...I thought as much:D ...

I'm thinking keep it simple....have two seperate cooling systems..but one working on the other to achieve the ultra low temp. as explained earlier(cascade system)

How do you mate the Evaporator from system "A" to condensor from system "B"........ to allow "A"to super cool "B"....

Is it a matter of bolting evap.& condensor back to back...this does not sound very efficient...is there a commercial product that will allow two different refrigerants to condense/evaporate in one unit...?


cheers

ps...I hope this makes sense...lol:D :shrug:

Well if this is your first system, I would expirement with some basic systems first.But if you really want to do it, the best way is to make your own coaxial condenser like I used on my second cascade system(first was just a watercooled condenser cooled with chilled water).To do that, you take say 15 feet of 1/2 pipe and 15 feet of 1/4 pipe, run 15 feet of 1/4 through the 1/2 pipe.But cut the 1/2 pipe down so you have more 1/4 than 1/2.Now there is 1/4 of pipe in the 1/2 pipe, then 1/4 of empty area.Well use the empty area as the evaporator for the high stage(system a), and the 1/4 pipe as the condenser for low stage(system b)

WOW...what a good idea:)

Are there any problems with bending a tube within a tube..?

How/Why 15 feet of copper tube needed..?? is it overkill..or can you never have enough overkill...??:D

I was just giving an example, I used 15 feet becuase that is how much came in the roll.You can use less.But I warn you, it is a real pain to bend, but it can be done. :)
Air cooled condensers usually have alot more than 15 feet of pipe.But for a coaxial condenser you don't really need alot.

Hey aenigma.....:)


I wonder if you or anyone can answer the 2nd & 3rd question at the beginning of this thread..

bowman answered your R50 question.
Not all compressors are the same, they are differant in power and everything but yeah if you flush the compressor and use the oil the refrigerant you plan on using uses, then it will work.As long as you don't use R50 or anything like that :)
Just regular refrigerants.

:D hello all

Keeping in mind I'm still planning my Cascade system can anyone tell me how do you choose two refrigerants that compliment each other to get these ultra low temp.


The comprssors need to handle very high presssures,I can't find/choose the correct compressor to handle refrigerants like R14 or R50.....I have not got the knowledge to choose the right item...HELP!!


I plan to use R14 or R50 as the end refrigerant to cool the CPU..:drool: :D :rolleyes: :) :D

Well I already said you need to build a regular one before venturing into this, becuase it is not easy.Chosing the refrigerants is the easiest part in fact.I don't think you understand quite how a cascade system works, becuase you don't need a compressor to handle a high pressure if your using R14 R50 R23 etc. in a cascade low stage.Make a basic phase change system and learn alot about it before you even think of trying it.
I have thought about it too, using my 4-6hp a/c comrpessor and a 1.5hp(?) semihermetic copeland, but they are 220v so I changed my mind.

Hello

I am building a "regular"set up first....it just so happens to be two of them ganged together to make one monster.....

All I lack is knowledge....won't start the build till I understand the concepts you(aenigma) and others are trying to explain....so I keep asking "stupid" question, searching the net for answers.

"YOU DON'T GET, IF YOU DON'T ASK"



:rolleyes:

Is there anything better then a cascade system and what is the best feon for the cascade system.

Hey aenigma is there a better way to do it for even better temps.

There is also a 2 stage system, but cascade would be lower esspecially if you went all out(dont try this at home) and used low boiling point refrigerants.Like for instance a triple cascade system using R290 R170 and R50(propane ethane and methane).But don't count on making a system like that. ;)

No the coaxial condenser I just explained how to build is a very efficient condenser as refrigerant is directly boiling on the condenser of the other system.

So there is noway i chould build a triple cascade system.(That just makes me want to build it more:evilaugh: )

Well you could, but you probably won't get it right.To build a cascade system you need to know refrigeration pretty well.Start off with basic systems...

I rather make a super cooler on the frist project this way i would save time

No you won't save time becuase it isn't as easy as you think.You need to know refrigeration if your going to make a cascade system.You will waste a lot of time because it won't work right the first time, and you will probably waste money too.

I know it will take time but I have the time to do it.

I guess i should just build a 1 stage syste and i wanted to know if I shoud use R508B or R22 REFRIGERANT.If there something better then these 2 REFRIGERANTS can u plz tell me.

Do u think i can build a 3 stage system:D
I have no idea how 3 stage works tho:mad: