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To start: Ethylene can not be used in an autocascade with that compressor. That's much to weak.Quote:
Originally Posted by Frozen_Neko
If you have never build a single stage system, the odds are that your autocascade will never run beforce you made one. Try a single stage system first ;)
Your hx needs to be able to hold -20C to condense CO2 at ~ 300psi. Less than 225psi would be ideal with a hx temp around -35 or so. Ethylene requires your hx to hold -40c for safe pressures and would not be doable with a small compressor, but maybe with >1hp.
I may end up cascading now instead of an autocascade because the compressor i picked up isn't all it was made out to be. Though i'll find a use for it anyway.
I have some thoughts but they are unrelated see post titeled theories and questions.
I'm going to pick up a UEI DT200 thermometer for $154 and a 9L tank of CO2 for $165 plus a regulator for $121 (USD).. this co2 stuff is adding up. I thought it was supposed to make this autocascade competition affordable ? :(
edit: I HATE air liquide for their pricy cylinders! I cant find used ones anywhere.
Maybe e-bay? In Poland we have a internet auction, like a e-bay, and there CO2
bottles (large, 5-10kg with valve, used) costs something around 65$
i saw some 10lb tanks for 82$us on ebay that will ship to canada but after taxes brokaerage an all it will end up being about the same price as I would pay at airliquide which is $175cdn for a new 5.9kg (9l) tank, not including regulator or fill.
BBQ gas and co2
not bad hey anyone can get those gases
http://www.xtremesystems.org/forums/...id=24086&stc=1
http://www.xtremesystems.org/forums/...id=24087&stc=1
http://www.xtremesystems.org/forums/...id=23905&stc=1
Wow.. getting up there kayl!
I built my hx today for a test autocascade (with only a ~1/4hp compressor, its about 1' long). I'm going to build a larger hx if this one works well..
edit: forgot to ask what's your hx temp?
secrete, at -66c hx is -33c it its a little warmer though at -72.2c, actual temp is avator
My ice bath wont go below 0.5c, maybe i need to insulate it or crush the ice smaller. Is this close eneough?
Mine is off a small amount also, but it's close enough for the girls I go with.. :slobber:
I know there is an adjustment screw on the back of the thermometers, but I really don't want to jack with mine.
AFAIK there is no adjustment screw on the DT200's and they must be opened and digitally calibrated. I think mine is .5 off and its brand new :(. Anyone know how much calibration costs, or is it free or something (UEI's office is really close to where I live).
i wouldnt be worried about that, its only if you have like a -5c offset or something.
try crushing heaps of ice and adding just a tad of water. should go -0.2c to 0.2c.
Made a phase separator today. I hope the pipe is large eneough to slow down the gas.liquid, I use 1 1/8".
Some changes to my participation to this contest.
I scored 2 SC18C's today and you can calculate what 1+1= ;)
What do you think about R290+R744+R1150 cooler. Autocascading first stage and ethylene in the second;)
there is a lwoer capcoty on a autocascade, you would be better off having a single for the first stage. auto cascading the second is plausible though. If you feel you want to do 744+1150 you have to realize your vacuum is controlled by the 744 condensing the r1150 so your temps woudlnt be any better condensing at -70c as apposed to -40.
No I will try to use R290+R744 for first stage and R1150 rot the second:P If it wont work I will change it to R404A.
i was saying that first compressor will not hold the load of r1150 if its autocascaded.
Have you tried it? I will try it and if it wont work I can easily cange it to 404A:)
o your saying the whole first stage not just the r290 :) oops.
Wow...I'm getting pretty intoxicated at this time...(23.57...) I'm not used to friday nights at home after full week of work... The cascade will be R290+R744 if that goes well or if it won't Then I Will use R404A in the first stage:)
Pc :slobber: Ice has his autocascade running with r290 + r1150, apparantly around -80C
im thinking of trying something similar, i dunno if it would be able to hold temps under load at all tho :(.... would a 1hp compressor be strong enough?Quote:
Originally Posted by gkiing
I think a 1hp compressor would be plenty, I bet even a 1/2hp sc12xxx or rotary could pull it off. I can condense CO2 with a 1/4hp compressor in my test autocascade.
i think he used r22/1150.Quote:
Originally Posted by gkiing
i think he should start a post for it.
hatemi i agree with jsu a autocascade would be very hard to build to hold a hx floded at cold temps as 1st in a cascade.
i like plan 2 though r404a / 1150 autocascade
even test it with 744 then switch to 1150.
then entering 2 comps.
whats the pressure needed to condense 1150 at -35c?