Typical beginner Questions.

[Something Sexy]

As build date approachs, I have a few more typical beginner questions. I am builing a basic water chiller. The compressor I am using is a LG rotary compressor rated at 430W (roughly 1/2 HP right?). I am going to be using R22 for my first build, easy and cheap. The condensor I am using is a Chilly1 style condensor. Couple questions or just need some comments on what I am gonna do.


1. As far as cap tube, I believe I decided on 10 feet of .031, I know you can't get exact what I need until I try and test, but does this sound like a fairly good estimate?

2. As far as evaps go, I am going to be custom building one, most likely one coil, is there any specifc length the evap coil should be total? The most surface area the better, but is there a limit to this? And as far as the evap ID, should it be the same ID as the compressor lines or does that no matter?

3. Compressor fans, what kinda fans are you guys using? Just basic computer case fans or do you guys have some industrial beasts? I am looking for some in the 120mm range.

4. As far as coolant goes, I am thinking of just using 100% alcohol, is there anythiing better? And I would like to use Tygon for my tubing, does anyone know if the tygon is not compatible with alcohol?


Any input on anything would be awesome. Thanks guys.

[catkicker]

formula for determining size of compressor
EXAMPLE
amps X volts = watts
6.90 fla(full load amps) X115 volts = 793.5 watts

1 hp = 746 watts

793.5 divided by 746 = 1.06 hp


Cap tube sizing http://www.teampuss.com/forums/viewtopic.php?t=74

captube conversion chart
http://img477.imageshack.us/img477/9471/captube9ck.th.jpg (http://img477.imageshack.us/my.php?image=captube9ck.jpg)

Evap. 12 to 15 feet of 3/8s copper tubing seems to be the most common type made.

As far as fans I'm useing a 120mm panaflo
http://www.svc.com/fba12g12m1a.html

I'm going with denatured alcahol & glycol based antifreeze coolant mixture
of 70% denatured alcahol and 30% coolant

[Blaster]

Cat has answered most of ur questions :D


just to say that tygon tubbing works fine with alcool, oh and the fans are to cool the condensor not the compressor :p

[Something Sexy]

Thanks for the information guys...heh heh yea I meant condensor there.

[RussC]

10ft of cap seems long for R22 and 1/2hp compressor. The cap tube is a trade off of capacity vs temp. Whats the heat load? What temp are you looking for? That will determine the length. A 1/2hp compressor is good size, so a very restrictive cap tube seems like overkill, and will limit capacity, but the temp "may" be lower depending on load. R22 doesn't need alot of front side pressure to condense, like the more exotic refrigerants. If the the load is very high, then the long cap will restrict capacity so badly, it wont cool the load. If too short, then temps will be higher.

RussC

[Something Sexy]

How do we estimate load? I am running it on a San Diego 3700+, which has a 89w rating, but for overclocking I am not sure how much extra that adds.

[RussC]

Good question, you don't know, and really can't easily find out. Your stuck with trial and error, so changing cap tube length is the only way, then test each length.

The other way is to go TEV or CPEV.

RussC


How do we estimate load? I am running it on a San Diego 3700+, which has a 89w rating, but for overclocking I am not sure how much extra that adds.

[Stewie007]

Yeah, you get a TXV matched to your compressor size, and externally balanced and bam, yer set. No shortening bloody cap tube, and you can adjust it too.

[catkicker]

http://img398.imageshack.us/img398/3741/expansionvalve3sz.jpg (http://imageshack.us)

After doing some reading I decided to go with TXV, cap tubing would have been easier for me to setup and the valve has required me to do alot more research and alot of question asking LOL. I think I drove Chilly1 bonkers with all my questions. In the end I think it will be worth it.

[Something Sexy]

Yeah, you get a TXV matched to your compressor size, and externally balanced and bam, yer set. No shortening bloody cap tube, and you can adjust it too.


So I could get an expansion valve watched with the size of my compressor and I should be set? What is the difference bewteen and external and internal equalized one? And what would be easier and better?

[RussC]

Download the catalog from Parker/Hanofinn or Danfoss. It will have all the info you need.

RussC


So I could get an expansion valve watched with the size of my compressor and I should be set? What is the difference bewteen and external and internal equalized one? And what would be easier and better?

[Something Sexy]

Another quick question on reservoir types, what are you guys using for your reservoir, my first idea was just get a copper pipe, but pvc is cheaper and easier, do you know of any reaction problems with pvc and alcohol?

[Marvin]

the pvc reservoir can crack under very low temps.
Mine cracked.:(

[Something Sexy]

Interesting, have any other ideas for substitues?