autocascade refrigrants

[tim-]

Hi everyone.
i'm currently building a autocascade.
in sweden we have restrictions about refrigrants such as r12/r22 etc so those gases isn't a possibility for me.

I have been thinking about running r1150 as low stage as in this build.

my question is if r404 or r507 will work as high stage? otherwise what do you guys know about r1270? what I'm wory about if how it will be in the phase sep.. I need a high stage gas that don't mess up the r1150.

I'm not a chemist and have hard time to try understand how those refrigrants will work togheter.

I know straight gases is to prefer in auto but I would like to know if someone know anything?

this is going to be a serious build and r290/co2 isn't an option as I'm aiming for lower temptures then the co2 pt-chart will allow without risk of dry ice. I'm aiming for something like -80-85 @ 2x250watt.

regards
Tim

[Xeon th MG Pony]

Well R-290 is direct substitute for R-22

[[XC] gomeler]

r290/r1150 would work well.

[Freddie123]

I'm fairly sure LukeXE uses R290/R1150 without any problems

[tim-]

well I do want to avoid to use r290 if it's possible as it isn't as good as r404/r507 or r1270..

r1270 is propen, which is a same family as r1150 and r290 but with a boilingtemp of -48*c.

as I'm planning for huge load I do need a really strong first stage and I don't think r290 will make it.

main problem is how those gases will act in a phase sep.. what will work or not?

I'm pretty sure I in the end will stick with a non-blended first stage gas to avoid problems.. but want some input on what will work in first stage with r1150 as lowstage gas.

[Xeon th MG Pony]

Well avoid 404a, avoid the zeotrops as when they fractionalize it's a pain, stay with R-507.

[tim-]

yes I was thinking about that problem with r404.. but I wasn't sure how it was with r507..

well then it's about r507 or r1270.. any input about r1270 will work well together with r1150?

regards
Tim

[n00b 0f l337]

Read over whats been done, and see others failures and try and figure out why. Autocascades are not a game of boiling points.

[tim-]

no ofcourse it's not all about boiling temps but if It's possible to use a media that have higher capacity then another why not use it?

I know r507 have lower boiling temp but still.. it have more capacity. unfurtuntly I don't have 507 home at the moment only r404 which I know is useless.. therefor I'm going to buy either a new bottle of r507 or rent a r1270bottle (If I find any supplier). Ethylene is already requested and hopefully arrive this week. r290 is already in the workshop. It could be something to start play with and in the future be replaced by something better.

I have to accept that I'm good enough on my chemistry to do it.

If I'm not satisfy with results and gasmis I just make it a regular cascade, but that isn't as fun as a auto :(

regards
Tim

[n00b 0f l337]

R404a will not be useless, its r507a and r134a, and it might separate, but if both are condensed it will still run out the same phase sep.
Your pressures though with the mixes you are talking about will be quite extreme.

[tim-]

we will see.
I'm going for plate HX and 2kw rotary compressor so I think capacity is enough to keep temp on hx to ~-40 range.. which means that r1150 with a bit subcooling will be at 16-16,2bar(a). That's acceptable for me.

regards
Tim

[quintus]

too bad u cant use r11 r22 and r23...

[Moc]

R600(non A)/R290/R170 will gave you similar performance...

[n00b 0f l337]

The two people above me know a refrigerant blend that would work ;)