Some waterchiller questions

[RuKK]

Ok, so I have a 1/5hp R12 compressor which appears to work good, a new capillary drier/filter, and about 5' of ancient cap tube I cut out of a dead fridge. I originally intended to build a direct die phase change system, but I've ditched the idea for a waterchiller :/

Now, seeing I cant get ahold of R12, whats the best thing to run in this compressor. I believe it has mineral oil in it, so that lets out r134a and r404a (I think). How well will r290 (propane) do in this system, and if I'm carefull and make sure I have no leaks and good ventilation in my room, is it safe to run it 24/7? Besides r290 what options are there that will perform well (r414? I heard a refridgeration guy talking about it but cant remember what it was a substitute for.. might have been r22/r12 though).

Ok, so exactly how much 1/4" copper tube should I use for the evaporator? And how long should the cap tube be? I'm going to try and get ahold of some new capillary tube, but I dont want to get too little.

As for the condensor, will a large heatcore with a 100+cfm of air going through it be enough, or do I need something larger?

Alright, now that I've asked all my n00b questions, heres my retard question. I had the compressor tested by a refridgeration shop. Now, when the guy filled her up, he put a copper valve thing on the end of the factory fill on the compressor. He put a little valve thing in that (like whats on bicycle tires and stuff.. so your gas can go in, but not ocme out), and then removed it when he was done. Now, I like this idea, and want to put one back in. What are the correct names for this and the tools for doing it, and how exactly is it done?

Thank you very much guys,

-RuKK

[bowman1964]

Originally posted by RuKK
Ok, so I have a 1/5hp R12 compressor which appears to work good, a new capillary drier/filter, and about 5' of ancient cap tube I cut out of a dead fridge. I originally intended to build a direct die phase change system, but I've ditched the idea for a waterchiller :/

Now, seeing I cant get ahold of R12, whats the best thing to run in this compressor. I believe it has mineral oil in it, so that lets out r134a and r404a (I think). How well will r290 (propane) do in this system, and if I'm carefull and make sure I have no leaks and good ventilation in my room, is it safe to run it 24/7? Besides r290 what options are there that will perform well (r414? I heard a refridgeration guy talking about it but cant remember what it was a substitute for.. might have been r22/r12 though).

Ok, so exactly how much 1/4" copper tube should I use for the evaporator? And how long should the cap tube be? I'm going to try and get ahold of some new capillary tube, but I dont want to get too little.

As for the condensor, will a large heatcore with a 100+cfm of air going through it be enough, or do I need something larger?

Alright, now that I've asked all my n00b questions, heres my retard question. I had the compressor tested by a refridgeration shop. Now, when the guy filled her up, he put a copper valve thing on the end of the factory fill on the compressor. He put a little valve thing in that (like whats on bicycle tires and stuff.. so your gas can go in, but not ocme out), and then removed it when he was done. Now, I like this idea, and want to put one back in. What are the correct names for this and the tools for doing it, and how exactly is it done?

Thank you very much guys,

-RuKK
Well first off.
the compressor will run r134a if you would rather use that.you will have to change the oil is all.or r290 propane will work with the oil you have.
evaperator will work fine made out of 10ft of 1/4 copper tubbing.
the heater core is a no no.you will have to find a condensor or something simerlar.a heater core will blow open from the pressure,they are desinged for 15psi max and a condensor will reach 250psi.
the shop installed a scrader vavle on the tubing to test it.it will have to be installed on the compressor to fill and check pressures.

since you are new to this.please take some time to study phase change some.you can get injured very easy.

you can learn alot from
here (http://www.phase-change.com/)

[RuKK]

Thanks for the reply bowman, I've been reading a up on phase change for a few months now. I believe I understand the principles fairly well, I just dont have much experience with the practical application.

Now, with a 10' evaporator, how much cap tube should I start with? That 5' I mentioned earlier?

I know that in a phase change setup the longer the cap tube the colder the evap, the hotter the compressor and the less heat it can move. Other variables, such as evap size effect the most desirable cap tube length, correct?

As for the refridgerant, I like the advantages of r290 (very cheap, mineral/ester oil doesnt matter and a lower boiling point than r134a). However, if its too dangerous to use safely 24/7 I'll have to go with something else. The thing is I would really like to get colder than r134a. What are my feasable alternatives, considering my the size of my compressor?

Exactly how big does the condensor have to be, and does it matter if its steel? Thanks

-RuKK

[bowman1964]

i need to know the size of the capillary.to anser your question.

r290 will work fine.just be careful and work outside if possable.

condensor can be steel.or can be made from copper tubbing and water cooled.lots of ways to make it work.easyest is to find a old evaperator and use it.

[RuKK]

By size you mean the inside width, yes?

I just measured the outside and I have 6'4" of it. Now, I have no idea the inside width is as I ripped it out of a junked fridge. If I was going to buy some new cap tube, what length and "size" should I get? I really appriciate you helping me out with this man :)

//edit: I just measured it and the outside is a hair over 1/16" wide.. and I mean a HAIR.

-RuKK

[bowman1964]

ok.check this link it will give you a capilary chart that will help you alot..
capillary chart (http://www.supco.com/images/20%20cap%20tubing.pdf)

[RuKK]

Using the capilary chart and this (http://www.danfoss.dk/pdf/installatorringbind/cn60f102.pdf) on using r290 as a refridgerant from danfoss, I have concluded that I need 70" of .031" cap tube because, according to danfoss:


For R 290 experience shows the need for a capillary flow rate almost similar to R 404A. At least this is a good starting point for optimization

Thank you very much for your help bowman, your making the impossible not only possible but downright easy. I'll post some pics and results when I get the whole system running :)

-RuKK

[RuKK]

Hmm.. I just did some research and my compressor turns out to be a 1/6hp tecumseh capable of 450 btu/hour. Now, when I look at the cap chart for r404a, it says that a 1/5hp compressor uses 70" of .031" ID cap tube. Now, a 1/6hp r404a compressor uses 95" of .071" ID cap tube.. Couldent you get away with just slightly more .031"? What is the reason for going to a longer, wider cap tube? Thanks

-RuKK

[bowman1964]

Originally posted by RuKK
Hmm.. I just did some research and my compressor turns out to be a 1/6hp tecumseh capable of 450 btu/hour. Now, when I look at the cap chart for r404a, it says that a 1/5hp compressor uses 70" of .031" ID cap tube. Now, a 1/6hp r404a compressor uses 95" of .071" ID cap tube.. Couldent you get away with just slightly more .031"? What is the reason for going to a longer, wider cap tube? Thanks

-RuKK

first of sorry i missed this reply.

now compressor size will make no differnace as long as the compressor will meet the min requirements of cooling btu displacement.
for instance i have a 1hp and a 1/5hp compressor.if i set the same capillary tubing (say set for 200 watt heat removal @ -20c)on each the same,the compressors will still only remove 200 watts of heat.both being the same.only differance is the 1 hp may have a stronger vacuum because of the larger displacement of the pistion.

the capillary is metering the amount of refrigerant the evap recieves.so of course a smaller diameter tube will cause less refrigerant to pass but...making the tube longer or shorter fine tunes the flow rate.this is done by the friction caused by a longer tube lenght.so longer less flow,shorter more...


i hope this helps you

[RuKK]

Ok, so depending on how far my processor goes, how much vcore it requires and on idle/load, it will be making 80-120 watts of heat.

Now, that cap chart you gave me specifies cap tube length by compressor size. Thats just a approximation of how many btu\hr a typical 1/6hp, 1/5hp etc compressor is capable of, correct?

My friend is apparently going to make me a evaporator block along the same lines of the vapochill blocks, but I want to have the system tested and working by the time he finishes it, so how much copper tube should I use to simulate the block? Is 10' still good?

So for a compressor capable of 450btu/hour, is that 95" of .071" ID cap tube good for, say -20C evap temps with 80-120Ws of heat? Should I shoot for lower temps? Is -30C or less even possible for a setup of this type?

Sorry for all the questions, and thank you very much for your help.

-RuKK

[bowman1964]

ok i ran this on my program and got this anser.
using a 404 compressor for flow rating .
it says you need .600mm x 1.75m of capillary.which you convert to std size.
i took a pic so you will see all the specs i get,super heat everything. i hope this helps.

[RuKK]

Thanks for the pic bowman, its helped me a great deal. However, the problem I am now encountering is that I cant find any smaller than .026" ID cap tube. 0.600mm is .0244", so the difference in diameter will change the whole thing alot, or is .0244 to .026 not that big a difference in a cap tube? Should I add another few inches?

-RuKK

[bowman1964]

add about 6 to 10 inches.you will be very close