Can someone give me some cascade details?

[stockhatch]

I was wondering how long a tube-in-tube HX should be for one thing. Is there a formula? This will be an X800 VGA cooler, so relatively small loads will be applied. Also, are an accumulator and oil sep needed on a small vga cascade looking for temps in the 60s? It will be a 290/CO2 setup.

Thanks

[JSU]

There isnt a real formula. You should be fine with anything over 1ft :D if your only using CO2 (youd prolly have 275+ operating temps and 350~ startup). Though you should go alot longer than that ;)

[stockhatch]

Great. Thanks. How about the oil sep and exp tank? Im realistically looking at 40s-50s load temps. It may idle in the 60s, but I dont plan on letting it idle much anyways, so oil circulation shouldnt be an issue right?

Thanks again

[sandman]

oil circulation should be fine.

You don't need an EX tank, but they're pretty easy to add. If you need one PM me, I've got extra's.

[GuGaCoSa]

If your looking for -40/-50 you dont need to make a cascade and spend WAY more than just a normal single stage with r404a or r507 or r402a

[saratoga]

CO2 will get you quite a bit colder then that, even under load. Berkuit had his at -100C (unloaded of course). -40C would be a decient single stage system.

[stockhatch]

oil circulation should be fine.

You don't need an EX tank, but they're pretty easy to add. If you need one PM me, I've got extra's.

Thanks Sandman. As far as the ss vs cascade, I know I could probably build a single stage that would get almost as cold under load, but not with propane. Cost wise, I will have the expense of the copper tubing and the CO2 when I need it. I already have the rest of the parts. I am also wanting to build a cascade for the experience. If I can get some practice tuning with CO2, it will make an autocascade easier to tweak later on.

[stockhatch]

Can somebody tell me what the purpose of a receiver/accumulator is in a cascade? It looks like it would be for eliminating bubbles from the liquid line completely, is that correct? If this is its function, why is it necessary to completely eliminate the bubbles?

Thanks

[sandman]

it's for if you're using a TXV.

If you're using cap-tube, just build it like two single stages.

[stockhatch]

Ok, from some searching, I have found out that a receiver is used in TXV systems to ensure a bubble-free liquid feed. An accumlator is to ensure only vapor is returned to the compressor. Sorry if this is obvious, I am trying to clarify for myself as well as anyone else who is unsure of their functions.

[JSU]

thats cool, next time you might want to check out teampuss before posting ;) they have a ton of info on all those things.

[stockhatch]

Will do. I have actually been lurking about TP lately too since I started this project.