Polycold Modded Autocascade Rev.3!

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04-24-2006, 10:32 PM
kayl

Quote:

Originally Posted by Nyx

I might be wrong. But from his last post, the designs are not far from what we have. I think it is the type of refrigerant he uses for his autocascades.which most of us could not have access to, or do not have enough knowledge on the purpose of it. For example R123 was used in most of his autoc but most of the autoc in XS do not use such refrigerant.Maybe because we do not know its properties enough.
But still i would like to know how far his designs are from those in XS but i would be more interested to know the use of some of his unusual refrigerant like R123.

im interested in direction of flow on the hxs.
ie cc1 cc2 and coaxial hx
ie evap bottom up with high stage entering top exit bottom.
i cant confirm but it looks like one of the cc's flows high stage entering bottom??
04-24-2006, 11:28 PM
s7e9h3n

Ummm, I'm not sure that everyone understands that this unit wasn't built by Cryo-tek (although he can and does build units of his own). This particular unit was built by Polycold and therefore the schematic would be under NDA. Here's a basic diagram of a 3 stage autocascade. If you can't figure it out, then you shouldn't be building an autocascade yourself :p:

http://img114.imageshack.us/img114/7808/cryo11nv.jpg
04-24-2006, 11:45 PM
Jack

i always thought it was called a metering device,
cuz i've never seen a captube expanding :p:

But the schematic looks reasonable, 4 metering devices, 4 evap+suction / liquidline HX, 3 phase seperators :)
I'm just amazed that it actually works :D
04-25-2006, 12:02 AM
Unknown_road

we need to find out what is happening with the argon, now it just doesn't make sense. The pressure/temperature just isn't the way it should be with argon. When we understand what is going on with the argon, we might be able to build cascades that will hold a load at -140*C or something. wish I had those gasses.

btw cryo-tek, any idea what kind of oil is in the system? Since you got r14 in it succesfully and people here had oil issues between r14 and POE. Could you please answer a few of our questions?
04-25-2006, 12:06 AM
Jack

Quote:

Originally Posted by Unknown_road

we need to find out what is happening with the argon, now it just doesn't make sense. The pressure/temperature just isn't the way it should be with argon.

At that evap temp you should be having a pressure of about 45 bar! :eek:
04-25-2006, 12:07 AM
jinu117

Well have all gases except... R123... I just can't bring myself to buy 100lbs of it... anyone in US care to split (with proper license?)? It's pretty cheap per pound but only thing I see is 100lbs and 200lbs drums... bleh.
I do have r22, R23, R116, obviously nitrogen and argon handy... :P Just need to learn exact purposes and what happens to really get to it.
04-25-2006, 12:09 AM
s7e9h3n

Quote:

Originally Posted by Unknown_road

we need to find out what is happening with the argon, now it just doesn't make sense. The pressure/temperature just isn't the way it should be with argon. When we understand what is going on with the argon, we might be able to build cascades that will hold a load at -140*C or something. wish I had those gasses.

Argon helps lower the partial pressure of the r14 allowing it to evaporate @ lower temps. However, one of the drawbacks of adding argon is that it will increase discharge pressures. Argon is cheap and readily available - as you probably know already, it's a sheilding gas.......*How was that Cryo-tek? I'm sounding smarter already :p: *

EDIT - Forgot to add: The argon itself doesn't condense....
04-25-2006, 12:11 AM
s7e9h3n

Quote:

Originally Posted by Jack

At that evap temp you should be having a pressure of about 45 bar! :eek:

Evap temp @ -162C = 180psi discharge ;)
04-25-2006, 12:35 AM
Unknown_road

Quote:

Originally Posted by s7e9h3n

Argon helps lower the partial pressure of the r14 allowing it to evaporate @ lower temps. However, one of the drawbacks of adding argon is that it will increase discharge pressures. Argon is cheap and readily available - as you probably know already, it's a sheilding gas.......*How was that Cryo-tek? I'm sounding smarter already :p: *

EDIT - Forgot to add: The argon itself doesn't condense....

Sorry but I don't buy that, partitial pressure doesn't reach anything in the range of -140 with r14. just look at a PT-chart of it.
04-25-2006, 12:46 AM
s7e9h3n

Quote:

Originally Posted by Unknown_road

Sorry but I don't buy that, partitial pressure doesn't reach anything in the range of -140 with r14. just look at a PT-chart of it.

Ok...well, I'm just repeating what cryo-tek's told me. What is your theory to what is happening here? It would be interesting to hear :toast:
04-25-2006, 01:02 AM
boostedevo

Wow! I hate this smilie, but this is the thread it was put here for :)

:eek2:
04-25-2006, 01:35 AM
kayl

Quote:

Originally Posted by s7e9h3n

Evap temp @ -162C = 180psi discharge ;)

that is just amazing:slobber:
04-25-2006, 01:50 AM
jinu117

Lemme think clearly for a moment at 3:36 AM in the morning.... (had a customer unit i had to finish... he was here :))
So...
Argon takes volume in chamber... but doesn't condense or evaporates...
it certainly doesn't condense anywhere in loop, and is non condensable.
Obviously high side pressure do go up with this. With the artificially developed high side pressure, we see higher pressure differential than normally would have seen considering we still have same amount of gas without argon. All the evaporating happens same thus as in amount of refrigerant but the differential aids in creating more flow of liquid...or I think it should within reason. But as restriction didn't really change -captubing- we have condition in evap which refrigerant can expand better (well argon doesn't really expand unlike refrigerant obviously around temp we are dealing with)...? better temp is always lower suction pressure after all. so it must also translate the other way in this case... (gotta love how gas laws always goes hand in hand).
I think I am rambling off...
Now care to explain why nitrogen (other than it's boiling and melting point) is not a good candidate for this reason? Or is it...?
04-25-2006, 02:41 AM
wdrzal

better temp is always lower suction pressure after all.

wrong.
04-25-2006, 03:04 AM
jinu117

Quote:

Originally Posted by wdrzal

better temp is always lower suction pressure after all.

wrong.

Yeah... hmmm
I just thought about it and, realized... what is SUCTION pressure in this case... lol.
after what stage? I think that 20psi is combined suction pressure right before or inside compressor.... so it might be running well into vacuum for evap stage.
04-25-2006, 04:21 AM
esdee

Quote:

Originally Posted by s7e9h3n

Ummm, I'm not sure that everyone understands that this unit wasn't built by Cryo-tek (although he can and does build units of his own). This particular unit was built by Polycold and therefore the schematic would be under NDA. Here's a basic diagram of a 3 stage autocascade. If you can't figure it out, then you shouldn't be building an autocascade yourself :p:

http://img114.imageshack.us/img114/7808/cryo11nv.jpg

thats a nice diagram, anyone wanna trial and error captube length on such a system?? :slap: :D
04-25-2006, 05:23 AM
Unknown_road

Quote:

Originally Posted by jinu117

Yeah... hmmm
I just thought about it and, realized... what is SUCTION pressure in this case... lol.
after what stage? I think that 20psi is combined suction pressure right before or inside compressor.... so it might be running well into vacuum for evap stage.

NO! suction pressure is almost the same everywhere as long as you don't have restrictions along the way.

cryo-tek: trow some methane in the system!
04-25-2006, 06:07 AM
Nyx

How much argon would be required to drive the pressures up to 700 PSI at -120C which argon could turn partly liquid. If the charge is correct i believe that it will not drive the pressure up astronomically and might still help in maintaining the ultra low temps. And there is still an expansion tank, it could help slowly release the extra mix into the system if a captube is used. so this could also be a crucial point.
04-25-2006, 06:19 AM
Unknown_road

you want the system to work at 700psi??:slap:
04-25-2006, 06:29 AM
cryo-tek

Quote:

Originally Posted by jinu117

Well have all gases except... R123... I just can't bring myself to buy 100lbs of it... anyone in US care to split (with proper license?)? It's pretty cheap per pound but only thing I see is 100lbs and 200lbs drums... bleh.
I do have r22, R23, R116, obviously nitrogen and argon handy... :P Just need to learn exact purposes and what happens to really get to it.

No 123? try 11 or 114
04-25-2006, 06:36 AM
404Power

Well ... first of all ... cryo-tek: Your units go LIKE HELL! :eek: :slobber:
I'm a fan of autocascades .... but your's beat everything I knew til now! :banana:
REEAALLLLLLY NICE! ;) :)

Short question:
How long does this nice unit need to come down to ... let's say .... -100°C? :)

regards
404Power

PS: PLZ check your PMs! ;) :) (I only wrote one ... not 3 or so! :D :nono:)
04-25-2006, 06:45 AM
Nyx

lol cyro all of us want to know how does the argon work in your system without having sky rocket pressures. pls explain.
04-25-2006, 06:56 AM
Waus-mod

Let the guy dont get 1000 pm's in an hour guys like stephen said... this will work not in our favor!
04-25-2006, 08:08 AM
cryo-tek

Quote:

Originally Posted by Unknown_road

Sorry but I don't buy that, partitial pressure doesn't reach anything in the range of -140 with r14. just look at a PT-chart of it.

I need to get some work done but here is a quick bit. These are ROUGH ROUND NUMBERS !! Please don’t beat me up over a small % of error.

Argon works best in the three stage units. (3 seps, 3 CCs)

Two or is this three theories on the argon:

1) Argon lowers the partial pressure of the R-14 in the evaporator allowing it to evaporate at lower temp.
Evap pressure: 25psia (10.3 psig) R-14 Evap temp = -120c.
Add the argon: 50% by pressure.
Evap pressure: 25psia = 12.5 psia R-14 and 12.5 psia argon. Evap temp = -130c. (see your PT chart) More argon = lower temps.

2) Argon dissolves into the liquid R-14 and lowers its evaporating temperature. (i.e. Glycol and water).
3) All of the above.

You guys are keeping me awake at night. CAFFINE !! I need a another Dew:eek:
04-25-2006, 08:54 AM
cryo-tek

I’m trying to answer questions and work for a living, this was in a PM so I’m posting for all to see.
#1 behavior of r123:

The R-123 condenses easily in the condenser and will dump large amounts of heat. The R-123 also helps with oil management in the #1 Phase Separator and compressor cooling.

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