Autocascade Drawings

Thanks for answer ! I understand all now.

For example, when I used R22/CO2 I can achieve really hard about -60*c idle, with R290/CO2 I can got easly -75*C @ 0bar without any problems. I don`t have to write, that with R290/CO2 I` ve got much better load results (about -65*C @ 160W), with R22/CO2 only ~ -55*C or more with that same load.

BTW, loaded temps on HX with R22 or R290 are very similar, but evap temp is different, so idea with oil, which is lowering heat transfer in HX, is really on place in that case

Cheers

mytekcontrols, can you write to me pm with you msn account name ?

Hmmm good point on oil being an insulator. I was going to avoid the propane due to the flammability but I may rethink that and use a bit for oil movement.

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Originally Posted by Unknown_road

ok, I assume it is for the autocascade you posted a drawing off a few posts back? Why are there so many (high pressure?)cut-off valves? also the solenoids seem to be placed wrong, can you explain the reasoning behind these, I'll calculate something up when I now if these have any effect.

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Thanks a lot! :) would be great!!

@ cut-off valves: I'm sorry, but since my mothertongue is German, I meant some shut-off valves like these ones for example:

http://www.kaeltetechnik-shop.at/ima...ges/1254_0.jpg

The idea behind those was to be more flexible @ the captube lengths after building the unit! ;) New problem: I didn't think of the air which will be inside those captubes after changing its length! --> no more shut-off valves in my auto-c ... I'll edit mydrawing soon! :)

@ the solenoid valves:

The first one @ the direct connection between the bottom of the first phase-sep and the suction line was first plazed after a oilsep directly behind the desuperheater! But mytekcontrols gave me his advice to build it this way because a rotary with ~ > 2HP like this (2,5) should have no problems with a direct connection between HD and ND for about 5sec's per 2/3 minutes! Do you understand? :)

Second one will be used for a faster cool-down @ boot-up! :) It will we kept closed during the first 10-15 minutes and after that, I will open it to get the auto-c's full cooling-power! :D :) Right? ^^

btw.: Thx again for your help too! :)

regards
Patrick aka 404

shut off valves shouldn't be used in autocascade piping imo. too dangerous, forget one is closed and the high pressure gas will build up very fast with no where to go. Same goes for solenoids in high pressure gas piping, the one you placed there is very very dangerous!!

the other one below the phase sep; I still don't get it's function, seems to me like your routing liquid refrigerant directly in your suction, which is bad.

the solenoid for faster pull down should be placed from a liquid point (earlier phase sep) to the cpu evap,with some cap tube offcourse.

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Originally Posted by Unknown_road

shut off valves shouldn't be used in autocascade piping imo. too dangerous, forget one is closed and the high pressure gas will build up very fast with no where to go.

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Hmm .... OK! .. I agree! Didn't think of this! :rolleyes:

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Same goes for solenoids in high pressure gas piping, the one you placed there is very very dangerous!!

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A few people already told me that a solenoid @ this position would be the best solution! :) Except this one:

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the solenoid for faster pull down should be placed from a liquid point (earlier phase sep) to the cpu evap,with some cap tube offcourse.

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I know what you mean! ;) But my problem is (as mytekcontrols already wrote some posts above!), that I don't have any source for solenoid valves with an operation temp. below -40°C! :( So I'm afreiad of a leaking solenoid valve @ this position because of the temperature there! :( 2nd problem is, that it's a little bit difficult to reach the inside of the evap with 2 cap-tubes! (But I think finding a good solution shouldn't be too difficult! :))

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the other one below the phase sep; I still don't get it's function, seems to me like your routing liquid refrigerant directly in your suction, which is bad.

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Please read this Quote here first! :) :

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Originally Posted by mytekcontrols

On face value I would say it does, assuming that R290 and R600a are not good solvents for oil (I don't have this information available, so I am guessing on this part). If you can use at least 1 high boiling point refrigerant that is a great solvent for oil, then you can rely on the 1st phase separator to return it to the compressor for you without causing problems in the colder stages. If not, then a full flow oil separator is your best bet. [...]

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(... as you know: R600a and ESPECIALLY R290 are VERY good solvents for oil! :))

regards
-404

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Originally Posted by 404Power

Hmm .... OK! .. I agree! Didn't think of this! :rolleyes:



A few people already told me that a solenoid @ this position would be the best solution! :) Except this one:

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lots of people here talk without thinking(or even worse, they think they know it but it's actually total crap) , they are a danger for a whole lot off people. A solenoid there is very dangerous and doesn't help pull down. I have seen a few people here whining that walt talks to much about safety but walt is soooo right about this subject. Not enough people here grasp the dangers of high pressure gasses.
Hope I didn't offend to much people but the solenoid over there is uberdangerous.

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I know what you mean! ;) But my problem is (as mytekcontrols already wrote some posts above!), that I don't have any source for solenoid valves with an operation temp. below -40°C! :( So I'm afreiad of a leaking solenoid valve @ this position because of the temperature there! :( 2nd problem is, that it's a little bit difficult to reach the inside of the evap with 2 cap-tubes! (But I think finding a good solution shouldn't be too difficult! :))

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then use the solenoid for liquid propane which isn't -40. It's all about some pre-cooling of the heat exchangers. Problem is that the propane carries oil through the whole system.

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Please read this Quote here first! :) :

(... as you know: R600a and ESPECIALLY R290 are VERY good solvents for oil! :))

regards
-404

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and that's why you don't need a solenoid for the oil return, the propane will carry the oil back to the compressor after it has evaporated in the HX.

Ok ... I see! :)
So your advice is to LEAVE OUT the solenoid @ the bottom of the 1. phasesep. because propane carries the oil trough the whole unit back to the compressor?! ^^

2nd advice is to use the solenoid valve for a direct connection between the bottom of the 1st phasesep. (--> liquid propane) and the evap (with a captube of course! ^^) to get a good precooling? After 10-15mins this solenoid will be closed! Am I correct? :)
(SRY again for my "dumbness" @ undertsanding some of these things! :( Sometimes I just have problems to understand it since English isn't my mothertongue! :()
TIA!

regards
-404

EDIT: New Version! :D :)

http://img376.imageshack.us/img376/3...lannew3ug2.png

EDIT 2:
New problem??? Liquid propane goes through the captube to the evap --> as we know: propane carries oil --> "clogged" (right word?) captube?
Hmm .. don't know what to do now! :D :(

My german isn't that good unfortunatly, you don't speak Dutch by any change do you? mein Deutsch ist sehr slecht.

yes the propane and butane carry the oil through the r600a/r290/r23 HX so that it doesn't get in the lower temperature parts of the system. Problem with the solenoid positioned like this is that the propane carries the oil into the whole system, but since it's only for few minutes I geuss it'll be ok.

@ Unknown_road:

I see! :) OK ... I will do it that way then! :)
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I'm sorry, but I can't speak Dutch at all! :D :( I think we'll have to keep everything in English! ;)

btw: YGPM! :)

R022- NBP: -40.8C; Ct:096.2C; Cp:600psi; BTU/Lb:0,946
R290- NBP: -42.2c; Ct:096.7C; Cp:616psi; BTU/Lb:21,625

Ct = Critical Temperature
Cp = Critical Pressure
NBP = Normal Boiling Point

Aperantly R290 kicks R-22s ass just as I have all ways said, you can't beat nature!

Xeon, your forgetting an INSANELY large factor.
Latent heat of vaporization.

eh have to find that data again, but as I recall R-290 out performed R-22 in actual field tests and cycle energy over life time, For AC aplications it performs excelently, I'm going to do a 6,000BTU test run with it in a heat pump aplication. still awaiting parts to arrive though.


R-290 enthropy of vapourization @ -25C in Kj/Kg: 406
R-022 enthropy of vapourization @ -25C in Kj/Kg: 223

Sorry there it is.

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Originally Posted by Unknown_road

lots of people here talk without thinking(or even worse, they think they know it but it's actually total crap) , they are a danger for a whole lot off people. A solenoid there is very dangerous and doesn't help pull down. I have seen a few people here whining that walt talks to much about safety but walt is soooo right about this subject. Not enough people here grasp the dangers of high pressure gasses.
Hope I didn't offend to much people but the solenoid over there is uberdangerous.


then use the solenoid for liquid propane which isn't -40. It's all about some pre-cooling of the heat exchangers. Problem is that the propane carries oil through the whole system.



and that's why you don't need a solenoid for the oil return, the propane will carry the oil back to the compressor after it has evaporated in the HX.

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Thanks unknown,I appreciate the support it seems to me most skipped basic physics. Walt

Something as simple as a closed valve or closing one when it should not can cause a catastrophic failure, from a pressure rupture, to the meltdown of of nuclear reactor core like at three mile island ,all because a valve was closed supplying cooling water to the core. I know the difference between the outcome of the two situations, but in commercial operations certain places valves are not allowed to be placed,and if needed,a complete failsafe safety circuit must be designed. As we all know no matter how fail safe a design is, We don't trust our machines enough to take complete control from humans. With humans, comes Human ERROR.

AS unknown eluded too some of what is being posted is made up as a thread s progresses by some members ,and that can be dangerous.

I going to stay out of this auto cascade thread unless I see someone doing something way to dangerous, but I don't have time to follow every post.

Mytekcontrols, I'm going to ask the same basic question as I did to cryotek, these drawings been around for many years, may I ask why technical engineering information is not added to the drawings,Even, basic cap tube sizes,tube lengths and diameters ,separator volumes,pressures and mass flows don't accompany them? Most guys here are DIY type and between them all tens of thousands of dollars will be wasted trying to figure out a working circuit from scratch.

Is you reason here to teach other members how to build auto-cascades? as by your stated resume you are the man after 30 years R & D, and if so why not give above mentioned data as patents to original models have expired long ago. that would sure help a lot and save these guys funds from failures & possible dangers from experimenting.

Also As far as I know, a zero O.D.P. replacement charge has not been found for the older polycolds,could you comment on that also.

I'm sure the guys here would be thrilled with specfic information.

Boy does this stuff get out of hand, or out of context very easily. Just to be clear on this, I was not familiar with the refrigerants specified when I was first asked about utilizing R290 and R600 as refrigerants (never used these before). After looking up the information on these (thanks to an additional observation and question by LukeXE), it became readily apparent that these were excellent oil carriers, which as many of you know, is a good thing to have in an auto cascade system.

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Quoting 404Power... The first one @ the direct connection between the bottom of the first phase-sep and the suction line was first plazed after a oilsep directly behind the desuperheater! But mytekcontrols gave me his advice to build it this way...

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As for the additional valves that 404Power showed in his first drawing... these were not based on any of my ideas. My suggestion (which has been both proven and patented), was to add a "time or temperature controlled" solenoid valve (what I called a "liquid diversion valve") with a serially connected cap tube from the bottom of the 2nd phase separator, to the entrance of the evaporator. This valve would only be opened for a very short period of time on start-up, in order to initially pre-cool the upper stages, and thereby speed up the ability for the upper stages to decrease to a working temperature.

The way this works is based on the fact, that condesates that initially form directly following a warm start-up, will most likely be separated from the gas stream predominately in the 1st and 2nd phase separators. It takes a while longer until substantial condensates are available for use in the upper stages. If we take some of the condensate formed in the 2nd phase separator and feed it to the top (via the liquid diversion valve and associatted cap tube), we will jump start the cooling of the upper stages. Since the diversion valve's source is being taken from the 2nd phase separator, and assuming the oil has been virtually eliminated through separation in the 1st phase separator (as well as other good oil control practices like a temprite oil separator, and a good oil carrying refrigerant such as R290), there should be no problem with oil contamination of the upper cooling stages. In fact a system of this design was proven to work reliably, and has the added benefit of being a variable capacity system, through precise cyclic control of the liquid diversion valve (e.g.; warmer temperature operation with higher wattage capability v.s. colder temperature operation with lower wattage loads). You could also think of this as being akin to a transmission in a car, where you can shift gears to suit the load requirements.

If anyone is interested, I can probably find a copy of the liquid diversion patent for all to see.

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Quoted from Wdrzal... Mytekcontrols, I'm going to ask the same basic question as I did to cryotek, these drawings been around for many years, may I ask why technical engineering information is not added to the drawings,Even, basic cap tube sizes,tube lengths and diameters ,separator volumes,pressures and mass flows don't accompany them? Most guys here are DIY type and between them all tens of thousands of dollars will be wasted trying to figure out a working circuit from scratch.

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I have a simple answer to this. I don't have this information to give, and it is never something that was ever part of a public disclosure such as a patent. In fact to this day, much of this information is considered to be a trade secret, and I can't speak for cryo-tek, but I am still obligated to keep this secret for another 2 years because of a signed non-disclosure agreement I made with a previous employer (sorry). As for the statement that these drawings have been around for years, all I can really say is that this particular part of the forum was labeled as "Auto Cascade Drawings", and I didn't see anything posted here that remotely looked like the drawings that I posted, so I presumed that this would be of interest to someone. I figure any information given on this subject should be usefull to someone first starting out, even if it isn't useful to a veteran such as your self.

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Quoted from Wdrzal... Also As far as I know, a zero O.D.P. replacement charge has not been found for the older polycolds,could you comment on that also.

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A zero O.D.P. charge is used on their 552, 662, and 1102 models, but to use it in an older series unit would require that POE oil be substituted for the original Zerol 150, as well as installing dual serial fed full-flow oil separators directly following the compressor discharge (standard in the 552, 662, and 1102 models). It would also require flushing out the system to get rid of the remaining Zerol 150 which is not compatible with the new refrigerants. This can be done, but it is costly.

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Have you used methane in any of your autocascaded systems? If so, what (if any) problems did you have?

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Yes Methane was used in a now discontinued model that Polycold use to sell called the PFC-100. It was found to be very beneficial at bridging the gap between refigerants being used in the upper stage, and thus provided more load capacity. However just to be clear, the improvement in performance was small, but it was enough to warrant the addition. Also it was found that whereas a small percentage of the charge being made up from Methane yielded good results, trying to increase its ratio substantially actually ended up degrading the coldest temperature obtainable.

@ mytekcontrols:

Thanks for your answer! :)

One more question @ newest diagramm:

http://img376.imageshack.us/img376/3...lannew3ug2.png

New problem (:D): Since I don't have any source for solenoid valves which can operate in a temp range BELOW ~ -40°C, I think I'll have to do it this way and connect a "liquid diversion valve" with the bottom of the FIRST phase-sep (since liquid propane + R600a aren't that cold as liquid R23!) ... so .. what to do now with oil? Go back to the roots and build in a third temprite 340 (I will use these oil-seps also as phaseseps ;)) directly behind the desuperheater and connect it to the suction with a 2nd solenoid which opens every (let's say) 5-10mins for about 5secs? Or what would be the best solution in your opinion? :)

regards
-404

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Quoted from 404Power... Since I don't have any source for solenoid valves which can operate in a temp range BELOW ~ -40°C, I think I'll have to do it this way and connect a "liquid diversion valve" with the bottom of the FIRST phase-sep (since liquid propane + R600a aren't that cold as liquid R23!) ... so .. what to do now with oil? Go back to the roots and build in a third temprite 340 (I will use these oil-seps also as phaseseps ) directly behind the desuperheater and connect it to the suction with a 2nd solenoid which opens every (let's say) 5-10mins for about 5secs? Or what would be the best solution in your opinion?

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Yes a Temprite used for oil separation should improve your chances for success considerably, if diverting liquid from the 1st Phase Separator, instead of the recommended 2nd Phase Separator is your only viable option. I'm assuming that the Temprite 340 does not have an internal float valve to regulate oil return (unlike a Temprite 900 series), so that is the reason you are suggesting the use of a second valve. This seems reasonable, although you could also get by with a very small (low flow) cap tube to keep it simple.

Ok, I've got to ask... what does SLHX stand for? I know it's being used as what I called the Sub-Cooler, but cannot figure out specifically what the SL part stands for (the HX part is obviously Heat Exchanger). Please excuse my dumb question, because I have seen others use this term also.

Opps!! I think I just figured it out. Is it Subcooled Liquid Heat Exchanger?

Ya ... You are right! :) The temprite 340's don't have an internal floating valve ....
But I REALLY like your idea of using a captube for oil-return ... I'll think about this! :)

"SLHX" stands for suction line heat exchanger! :)
As you already told me ... there are no "dumb" questions! ;) :)

404Power, Thanks for the heads up on the question (now I get it :rolleyes: ).

Just curious, but what kind of temperatures and watt capacity are you after? I noticed that your system is a 2 cascade system, which is quite capable of very low temperature operation (assuming the load is small). So for instance, I'm guessing hypothetically that a 1hp 2 cascade system with Sub-Cooler, should be able to do -150C at around 30-50 watts. However as the wattage increases, a third cascade would probably be needed to maintain such temperatures.

:fact: Just so someone doesn't jump all over me, I do not consider myself an expert , let me repeat that, I am not an expert when it comes to auto cascade system design. Now that I have cleared that up, I'll go on to say that yes I do have many years experience in this field, and yes many of those years were spent doing Research and Development on these kind of systems (although much larger). However I never went to college, and instead learned on the job, mostly through empirical methods. I will offer my advice, but I don't want anyone to think that my answers are absolute truths. I would always hope that everyone here would also apply their own experience and education, and sort through the information available, before making any firm decisions on the approach that they will take in designing such systems.

Bottomline... I agree with wdrzal and Unknown_road, that this stuff can be very dangerous, so always get a 2nd or 3rd opinion, and if it still doesn't seem clear, then hold off until it does. Don't ever accept something as gospel just because some one tells you so (like weapons of mass destruction :woot: ).

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Originally Posted by mytekcontrols

404Power, Thanks for the heads up on the question (now I get it :rolleyes: ).

Just curious, but what kind of temperatures and watt capacity are you after? I noticed that your system is a 2 cascade system, which is quite capable of very low temperature operation (assuming the load is small). So for instance, I'm guessing hypothetically that a 1hp 2 cascade system with Sub-Cooler, should be able to do -150C at around 30-50 watts. However as the wattage increases, a third cascade would probably be needed to maintain such temperatures.

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No problem! :)
Hmm ... I'm after lowest temps @ about 150-180watts I would say! :D :)
But ... as you can see @ my diagramm ... I'm NOT using a 1HP comp or something like this! ;) My Mitsubishi rotary here is somewhere between 2,5 and 3 HP! :cool: :) So ... which temps @ about 150-180W's should be possible in your oppinion? :)

regards
-404

use a seperate HX for the r600a and the r290, I don't really know if this works well since r290 might be tempted to condens in the condensor but in my experience with autocascades I'd say lots of the r290 will condens in the other HX (dependent on temperatures offcourse)

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404Power said... Hmm ... I'm after lowest temps @ about 150-180watts I would say!

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Silly me, of course you want lowest temps (this is XtremeSystems afer all).

3hp should get you 200-240 watts, but only if you use 3 cascades (with 3 phase separators). I'm basing this on a 10hp 37cfm system (Polycold PFC-1100LT) that will do about 800 watts at around -150C. So proportionally speaking a 3hp compressor should do approximately 30% as well. This also assumes that your 3hp compressor is close to 11cfm. If it is less, then of course either you will get less watts, or a warmer temperature (depending upon how you want to look at it). This is because it's really all about cfm, and not strickly related to a compressor's horsepower.

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Originally Posted by mytekcontrols

Silly me, of course you want lowest temps (this is XtremeSystems afer all).

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dito! :D

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3hp should get you 200-240 watts, but only if you use 3 cascades (with 3 phase separators). I'm basing this on a 10hp 37cfm system (Polycold PFC-1100LT) that will do about 800 watts at around -150C. So proportionally speaking a 3hp compressor should do approximately 30% as well. This also assumes that your 3hp compressor is close to 11cfm. If it is less, then of course either you will get less watts, or a warmer temperature (depending upon how you want to look at it). This is because it's really all about cfm, and not strickly related to a compressor's horsepower.

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Ah .. OK .. I see! :) ... So ... which other gasses would you add to get to a 3rd stage? :)

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Ah .. OK .. I see! ... So ... which other gasses would you add to get to a 3rd stage?

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R14 and Argon, with the subcooler running at around -125 to -135C (final strainer temperature before refrigerant is expanded into the evaporater). This is where the subcooler really kicks A*s! Allowing an appreciable amount of the Argon to dissolve into the R14 for an obviously lower expanded temperature then what R14 could ever do alone, especially at the suction side pressure you will most likely be operating at (probably 20-30 psi under full load).

Opps! gotta get to work, chat with you later :)

@ mytekcontrols:

Hmm ... but as you know ... I already (want to) use R14 + Argon! ;)
But you talked about a 3rd stage ... so .. what do you mean? :( Sry don't understand what the subcooler has to do with a 3rd stage! :(

@ Chating: I would like to ... but ... unfortunaly it's 1h before midnight here atm! :D ;)

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Originally Posted by 404Power

@ mytekcontrols:

Hmm ... but as you know ... I already (want to) use R14 + Argon! ;)
But you talked about a 3rd stage ... so .. what do you mean? :( Sry don't understand what the subcooler has to do with a 3rd stage! :(

@ Chating: I would like to ... but ... unfortunaly it's 1h before midnight here atm! :D ;)

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As subcooler mytekcontrols mean slhx on 3 stage, if I understand well.

@ LukeXE:

There already IS a sub-cooler! ;) :)
UPDATE @ diagramm (oilsep):

edit runmc - It is much more convient for everyone if you size you pictures. thanks

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Originally Posted by mytekcontrols

As for the statement that these drawings have been around for years, all I can really say is that this particular part of the forum was labeled as "Auto Cascade Drawings", and I didn't see anything posted here that remotely looked like the drawings that I posted, so I presumed that this would be of interest to someone......

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+1 -> Mytekcontrols :clap:

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Just curious, but what kind of temperatures and watt capacity are you after? I noticed that your system is a 2 cascade system, which is quite capable of very low temperature operation (assuming the load is small). So for instance, I'm guessing hypothetically that a 1hp 2 cascade system with Sub-Cooler, should be able to do -150C at around 30-50 watts. However as the wattage increases, a third cascade would probably be needed to maintain such temperatures

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For what it's worth, Cryotek had told me that if I wanted more capacity out of my P-100, he'd actually have to BYPASS one of the stages (of course it would also bring temperatures up). I may be wrong since it was awhile back.....I'll give a Cryo-tek a call and see what he says.....

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But you talked about a 3rd stage ... so .. what do you mean? Sry don't understand what the subcooler has to do with a 3rd stage!

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Check out this diagram and compare it to your own.
3 cascade drawing with subcooler (SLHX)

Notice that this has 1 more stage (cascade #3) preceeding the Sub-Cooler (yes as LukeXE pointed out, SLHX in your terminology), and a 3rd phase separator preceeding it.

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I already (want to) use R14 + Argon!

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Yes in order to go much colder then -120C you will have to (unless you like running your compressor suction in a vacuum, which I would not recommend). It is irrelevant to how many stages your cascade has, but mainly related to the lowest temperature you wish to achieve.

It is possible to use the R-14/Argon combination in even the most basic single stage auto cascade. However don't expect to handle much more than just a couple of watts of evaporator heat load. It will also require running your compressor at a very high compressor discharge pressure vs. a very low suction pressure (high compression ratio), as well as taking much... much longer to pull down to operating temperature. What I am really trying to say here, is that using less stages with very low boiling point refrigerants, requires making the compressor do more work.

Or yet another way to describe it...
Having additional stages when using low boiling point refrigerants, creates a more efficient system, thereby requiring less work from the compressor. Of course this does have its limitations. At a certain point, and dependant on the number and types of refrigerants being used, adding additional stages will become redundant, and may actually hurt your performance. I guess a good rule of thumb would be to pay close attention to your compression ratio. If it requires considerably more then a 15-to-1 compression ratio to achieve your desired temperature (with a suction pressure in the range of 20-35 psi), or you are forced to run the compressor suction in a vacuum, then adding another phase separator and cascade should help. Assuming that your compressor is also of a high enough cfm for the task at hand (adding additional stages and lower boiling point refrigerants, will also impact on the required cfm needed to prevent the suction pressure from getting too high).

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For what it's worth, Cryotek had told me that if I wanted more capacity out of my P-100, he'd actually have to BYPASS one of the stages (of course it would also bring temperatures up). I may be wrong since it was awhile back.....I'll give a Cryo-tek a call and see what he says.....

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Yes he is correct. Of course you would also have to reduce the amount of Argon when doing so, and probably would not get nearly as cold. Although you would gain in the ability to handle more watts of heat load, while still maintaining a reasonable compression ratio. However If you didn't want to lose out on ultimate temperature, and still gain in system capacity (more watts), upping the compressor size would be a better way to go. Although this can only be taken so far until you would also be required to increase the flow capability (diameter increase) of your heat exchangers and cap tubes.

@ mytekcontrols:

Thx for your answer! :)
I just didn't know what the 3rd stage has to do with the sub-coller (/ SLHX)!
Anyway .... depending on my datasheet I have here, the successor of my Rotary, the NE-41Y, has a "flow-power" of 7,11m³/h! Don't know if that's enough! :( elec. power is around 2,20 kW! ^^

Which temps can you think of with 3rd cascade/stage with this comp? and which other gasses would you add? :)
TIA!

EDIT: WTF is this nice little thing? :D :) *KLICK*

regards
Patrick

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I just didn't know what the 3rd stage has to do with the sub-cooler (/ SLHX)!

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The 3rd stage has nothing to do with the SLHX. The SLHX can be used on even a single stage auto cascade. As I talked about earlier in this thread, the SLHX (Sub-Cooler) is most benificial whenever you have a refrigerant in the mix, that due to temperature/pressure conditions, will never be liquidfied. The SLHX promotes the absorption of this unliquidfiable (is that a real word?) component into any liquid refrigerant passing through the SLHX. In our case Argon would be the unliquidfiable component, and R14 would be the predominate liquid passing through the SLHX. End result: R14/Argon (in solution) condensate boils off at considerably below -120C.

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Anyway .... depending on my datasheet I have here, the successor of my Rotary, the NE-41Y, has a "flow-power" of 7,11m³/h! Don't know if that's enough!

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If I calculated this right, this would be the equivalent to 4.1 cfm. For -150C operation, I would suspect 100 watts would be the absolute best you could expect for heat load capacity (and that might be pushing it).

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Which temps can you think of with 3rd cascade/stage with this comp? and which other gasses would you add?

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If I understand the first part of the question, I think I already answered it. As to the 2nd part about which gases... R23, R14, and Argon are going to be essential. As for the higher boiling components, as I have also mentioned, my favorites would be R123, R22, Ethane. I say this because I know for a fact that this combination works quite well. However if you would like to avoid the HCFC constituents, then substitute R600 for the R123, and R290 for the R22. I can't vouch for the performance utilizing these substitutes, but I would imagine you'll do ok. There are other ways to go in order to create a non-flammable zero ODP blend, but I really prefer to not say what this would be, since once again I am treading on trade secret information. And in this case specifically, I would be revealing information I was given concerning a patent that is still in effect.

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WTF is this nice little thing?

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This is the condensing unit from Polycold's now obsolete product called a P-20.
This was a partially separated 2 stage auto cascade design that cryo-tek was trying to share towards the beginning of this thread.

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Originally Posted by mytekcontrols

The 3rd stage has nothing to do with the SLHX. The SLHX can be used on even a single stage auto cascade. As I talked about earlier in this thread, the SLHX (Sub-Cooler) is most benificial whenever you have a refrigerant in the mix, that due to temperature/pressure conditions, will never be liquidfied. The SLHX promotes the absorption of this unliquidfiable (is that a real word?) component into any liquid refrigerant passing through the SLHX. In our case Argon would be the unliquidfiable component, and R14 would be the predominate liquid passing through the SLHX. End result: R14/Argon (in solution) condensate boils off at considerably below -120C.

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Thanks for this very detailed answer! :) I think I got it now! :D ;)

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If I calculated this right, this would be the equivalent to 4.1 cfm. For -150C operation, I would suspect 100 watts would be the absolute best you could expect for heat load capacity (and that might be pushing it).
If I understand the first part of the question, I think I already answered it.

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Ah OK ... I see! :) SO I think I'll go for ... let's say: -140°C @ 150watts! :)

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As to the 2nd part about which gases... R23, R14, and Argon are going to be essential. As for the higher boiling components, as I have also mentioned, my favorites would be R123, R22, Ethane. I say this because I know for a fact that this combination works quite well. However if you would like to avoid the HCFC constituents, then substitute R600 for the R123, and R290 for the R22. I can't vouch for the performance utilizing these substitutes, but I would imagine you'll do ok. There are other ways to go in order to create a non-flammable zero ODP blend, but I really prefer to not say what this would be, since once again I am treading on trade secret information. And in this case specifically, I would be revealing information I was given concerning a patent that is still in effect.

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I'll HAVE TO use R600(a) + R290 because R-22 and also R-123 are forbidden around here / very difficult to get! :( ... so ... what about: R600(a) + R290 + Thane + R23 + R14 + Argon (R740)? I think this should give a nice mix! :D :)

Quote:

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This is the condensing unit from Polycold's now obsolete product called a P-20.
This was a partially separated 2 stage auto cascade design that cryo-tek was trying to share towards the beginning of this thread.

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Thanks for your come back! :)

One more thing: I also have a Copeland Scroll air-conditioning comp around here! :) The problem is that this scroll comp has an internal bypass valve which opens @ a HD/ND ratio of 1:10! --> 1bar @ suction / above 10bar @ discharge --> bypass valve opens! :(
Is this comp also useful for me? Don't think so! :( What's your opinion? ^^

regards
Patrick

404Power... Yes a blend of R600(a) + R290 + ethane + R23 + R14 + Argon (R740) should work:idea: And I think -140C @150 watts just might be achievable with the first compressor you mentioned (don't forget that the line connecting your chiller to the evap will probably account for at least 10 watts of this due to insulation losses).

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One more thing: I also have a Copeland Scroll air-conditioning comp around here! The problem is that this scroll comp has an internal bypass valve which opens @ a HD/ND ratio of 1:10! --> 1bar @ suction / above 10bar @ discharge --> bypass valve opens!
Is this comp also useful for me? Don't think so! What's your opinion?

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I don't think so either :nono:

In the USA at least 110volt is the norm though and I'm not one to spend alot on anything, I constantly ebay. If your only aiming for a -100C range what sort of load might be plausible with a 1hp range compressor (Reciprocating preferably.)

I'd say the compressor is worth some thing to you! Make a heat pump! :)

FYI Noob, higher voltage motors are more efficient and less costly to run in the long term, hence why most ACs and large equipment are 240- 660. The last company I was with had 1Kv starters and motors running at 760V massive Hp in the 3 zerro range if I recall, ran a massive hydrulic system.

Yeah but being in the USA its very hard to get 220volt, at least for me.

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Originally Posted by n00b 0f l337

Yeah but being in the USA its very hard to get 220volt, at least for me.

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http://cgi.ebay.com/NEW-TECUMSEH-1hp...QQcmdZViewItem
That should make one helluva unit....

Ah I meant not 220volt compressors, thats incredibly easy. But 220volt power.

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Originally Posted by n00b 0f l337

Ah I meant not 220volt compressors, thats incredibly easy. But 220volt power.

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Do as I do....bench in the laundry room :woot:

OT: It's about time Fugger gets these forums on an Opteron setup...Obviously, his Clovertowns suck...

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Originally Posted by n00b 0f l337

In the USA at least 110volt is the norm though and I'm not one to spend alot on anything, I constantly ebay. If your only aiming for a -100C range what sort of load might be plausible with a 1hp range compressor (Reciprocating preferably.)

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is this a respons to another post?

Well he's talking about 1+ hp compressors, and I'm just chatting about not having 220v to use these. The laundry room is always good and dandy though but a pain at least for me.

extension cord?

Hmmm now I'm thinking on that, but the hole premise of plugging into my drier room makes both the idea of using, OR selling, a complication.

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Originally Posted by n00b 0f l337

Yeah but being in the USA its very hard to get 220volt, at least for me.

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Every home in the USA has a 120/240 volt entrance. Now if you have natural gas also for major appliances such as gas dryer,gas water heater,gas stove you may not have 240 volt outlets. but the there is 240 volt in the main panel,phase to phase=240 volt............. phase to ground=120v........if your major appliances are electric they are 240v.


single phase service(entrance) panels have 3 wires.......... 2 hot & 1 neutral, plus a solid copper wire going to a least 1 ground rod......most residential services are 100 amp or 200 amp. A apartment building may have a larger entrance broken down into individual meters or large building say in a city is a different story they will have 3 phase power but still only wire 120/240 to apartments, the third leg(wire) or high leg along with the 2 low legs are used to power industrial equipment.

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Originally Posted by n00b 0f l337

Hmmm now I'm thinking on that, but the hole premise of plugging into my drier room makes both the idea of using, OR selling, a complication.

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Wire a electrical outlet with 240 volt to your room or where ever you want 240 volt. Do it like a pro,cut hole in wall ,run wire,install receptacle & cover,install breaker, Turn On:D . 12 gage wire is 20 amp breaker,10 gage wire is 30 amp breaker.you need double pole breakers and be sure to catch each phase when installing. The older boxes you could install a double pole breaker and have both poles on the same phase.Be sure to catch each phase.Newer boxes are made so a double pole can't be installed incorrectly.

I have to laugh :) because I started looking at some of cryo-tek's posts after the following question was directed at both him and I:

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... may I ask why technical engineering information is not added to the drawings,Even, basic cap tube sizes...

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:fact: Well this drawing seems to have cap tube sizes clearly written on it:

http://www.xtremesystems.org/forums/...1&d=1148929119
This was posted at:http://www.xtremesystems.org/forums/...d.php?t=101204

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n00b 0f l337 asked... If your only aiming for a -100C range what sort of load might be plausible with a 1hp range compressor

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I think s7e9h3n is more qualified to answer this question, since he owns a working 1hp auto cascade system, and has been testing it under real world conditions.

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Originally Posted by mytekcontrols

I think s7e9h3n is more qualified to answer this question, since he owns a working 1hp auto cascade system, and has been testing it under real world conditions.

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These numbers are from Cryo-tek's testing:

Load, Inlet, head, out, suc/dis
0 w, -123c, -123c, -123c, 13/145
50 w, -121c, -121c, -121c, 15/175
100 w, -121c, -120c, -120c, 18/185
150 w, -119c, -117c, -116c, 20/200
200 w, 116c, -100c, - 112c, 23/225

Remember, though, this is a 3 stager ;)


OT: By the way mytek....I've been trying to get ahold of cryo-tek for the couple of days so we could discuss starbucks :p: but it seems he's been occupied in meetings and other business stuff...expect an email from me as soon as I get in touch with him :toast:

Ya when I had my counter top stove installed I got them to leave an additional 3 feet of wire slack and picked up a 60amp disconnect 2*30 duble pole, or in other words 30Amp per phase or what ever fuse you put in up to a max of 30Amp per phase. That box will controll a standerd 240V socket and the third phase will be to power a NEMA 20 socket.

Bit of planning and you can have a very capable and safe to code install that suplies you 240 and 120 @ 20Amp. I personaly over size the wire for the breaker to ensure a very safe loading capacity, if the breaker is for 20amp use wire capable of 30amp and this gurentees the wire under full load will never be near its max capacity.

Following the NEC is sufficient,but of course you may have to add wire gage for very long runs, usually between 150 and 200 feet or longer(depending on actual load) you need to add for line losses & be sure your under the maximum rated temperature.All is covered in the NEC.

#12 wire is sufficient for 20 amps,.....#10 for 30 amps

but of course it never hurts to have it slightly over sized, gives you head room should the breaker ever fuse in the on possition (Have seen it happen on odd inductive loads) this way either the breaker melts or the machine does but not the wire inbetween. never too safe when it comes to electricity.

@ mytekcontrols:

What about the amounts of the gasses?
How much kg's of R14 for example do you think will I need for this unit? :) Because exspecially R14 is REALLY expensive! :(

As far as I've seen, its an equal amount of gas, 1:1:1:1.

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Originally Posted by 404Power

@ mytekcontrols:

What about the amounts of the gasses?
How much kg's of R14 for example do you think will I need for this unit? :) Because exspecially R14 is REALLY expensive! :(

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In the UK I think the problem we have is finding 'small quantities' of certain gases / liquified gases. Most companies only want to sell you large amounts! It may be different where you live though.

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Originally Posted by 404Power

@ mytekcontrols:

What about the amounts of the gasses?
How much kg's of R14 for example do you think will I need for this unit? :) Because exspecially R14 is REALLY expensive! :(

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I have a feeling I know the answer to this and it goes something like....."The charge is going to vary from system to system. It will all be dependant on the exact specifications of your particular unit. :p: "

I've watched Cryo-tek charge my Polycold a couple of times and he doesn't seem to use a "set formula" for charging it. Basically, we put the autocascade onto a scale and he charges/releases various gases until the charge "feels" right to him. I can almost definately say though, the ratio of gases was not 1:1:1:1 ;)

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Originally Posted by n00b 0f l337

As far as I've seen, its an equal amount of gas, 1:1:1:1.

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not to be an *ss but from this answer I have to conclude that either your blind or you know nothing about autocascades/refrigeration or you just say something to get a higher post count :lol:

edit: I almost forgot, stephen is right, there is no way to determine the charge on just a scematic. However I think 404power just wanted a rough figure. I can't help you on that though since I never worked with r14

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Originally Posted by s7e9h3n

I have a feeling I know the answer to this and it goes something like....."The charge is going to vary from system to system. It will all be dependant on the exact specifications of your particular unit. :p: "

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That is absolutely correct Steven :D. Anyone who knows what they are doing will most likely give that answer :p:.

404Power... most often single stages and cascades have been said to use around 50-100g as an estimate, but I don't know about R14.

I gave a ratio because I know theres different charges for all, but by searching patent information on these forms of coolers, and its easy to find, they are often listing like 20oz for first gas, 19 for 2nd, 18 for 3rd, 17 for 14th.

Just saying what I've seen.

FOUND IT; http://www.xtremesystems.org/forums/...d.php?t=114671

Thanks @ all for your answers! :)

As Unknown_road already said, I just want(ed) some "rough numbers" and no exact numbers! ;)

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Originally Posted by Brettbeck

In the UK I think the problem we have is finding 'small quantities' of certain gases / liquified gases. Most companies only want to sell you large amounts! It may be different where you live though.

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Yeah .. I know what you mean! :D But I don't have problems with this because cold-ice is really a nice guy and is willed to sell my really small amounts of R23, R14 and Ethane maybe! R600(a), R290 and Argon are already here @ my place! :)

@ n00b: Thanks for this link! :)

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Originally Posted by n00b 0f l337

I gave a ratio because I know theres different charges for all, but by searching patent information on these forms of coolers, and its easy to find, they are often listing like 20oz for first gas, 19 for 2nd, 18 for 3rd, 17 for 14th.

Just saying what I've seen.

FOUND IT; http://www.xtremesystems.org/forums/...d.php?t=114671

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the ratio is offcourse also completly dependent on the system.

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Originally Posted by Unknown_road

the ratio is offcourse also completly dependent on the system.

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especially on the volume ratio of high and low side of the stages.

Right but take this into consideration that with whatever design they had, which if you read the long long sentences is the same, you need only start to work around with that 1:1:1:1

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404Power asked... What about the amounts of the gasses?
How much kg's of R14 for example do you think will I need for this unit?

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Hmmm... very good question, and not an easy answer. I'll base my estimate on the unit that s7e9h3n has, which is a P-100. Now please keep in mind that I'll be using American units of measure.

The method that I use on charging this unit is based on both weight (for liquids), and pressure (for gases). Basically any of the refrigerants that are able to be a liquid under room temperature conditions when contained within a presure vessel, will be charged into the system based on their weight. Everything else is charged based on additive pressure as a gas.

Normally I would charge everything into a recovery tank (which is easy to weigh with an electronic scale), but if your unit is small enough, and presuming your scale can read high enough, you could weigh the unit directly as you add the refrigerants. If you use the external tank method of charging, everything can be charged into the tank and then later transfered into the evacuated unit, using the unit's own compressor to suck out the contents of the tank (front seat suction valve). This later method is nice, since you can create premixes for your unit, and in the event of a leak and subsequent repair, a field recharge could be easily done.

Anyway... after the liquids are charged into the evacuated system (or tank) based on weight, you will end up with some amount of positive pressure in the system (or tank) which I'll call the "balance pressure" for the sake of giving it a name. This balance pressure (B.P.) will be the combined partial pressure of the liquids as charged. With the refrigerants I would use (R123 & R22) this ends up being approximately 15 psi in a P-100 (approximately 14 ounces of liquid by weight). Using the 15 psi as your starting point, you would add the following gases in the ratios shown below.

As charged into unit: (Unit Volume = 0.55 cubic feet)
Total desired unit B.P. = 115 psi - 15 psi = 100 psi = total pressure of gases to be added.

R23 30% (add 30 psi to 15 psi liquid partial pressure = 45 psi B.P.)
R14 50% (add 50 psi to 45 psi previous B.P. = 95 psi B.P.)
Argon 20% (add 20 psi to 95 psi previous B.P. = 115 psi B.P.)

Note: Due to soak-in, when adding a given refrigerant gas, allow 5 minutes to pass between gas additions, and top up before preceeding to the next one.

As charged into Recovery Tank: (Tank volume = 0.78 cubic feet)
Total desired tank B.P. = 80 psi - 15 psi = 65 psi = total pressure of gases to be added.

R23 30% (add 19.5 psi to 15 psi liquid partial pressure = 34.5 psi B.P.)
R14 50% (add 32.5 psi to 34.5 psi previous B.P. = 67 psi B.P.)
Argon 20% (add 13 psi to 67 psi previous B.P. = 80 psi B.P.)

Note: Due to soak-in, when adding a given refrigerant gas, shake tank between gas additions, and top up before preceeding to the next one.


!!! IMPORTANT !!! remember to always charge liquids into the discharge (high pressure circuit) only. So if you are using the premix tank method of charging, invert the tank (or use the dip-tube valve if it has one), and charge everything intially into the discharge side of the unit. When the pressure on both the high and low sides of the system have balanced, close off the hi-side valve on your charging manifold, open the low-side valve, front seat the compressor suction valve, and activate the compressor to draw in the remaining gases from the premix tank. CAUTION... Do not run the compressor in a vacuum for more than 4-5 minutes, since heat build up in the motor windings will not have a way to escape in the rarified atmosphere.

:fact:
The information given above, is only an approximation of the actual refrigerant charge amounts, is based on a particular blend of refrigerants, and a particular type of unit. You will of course have to make adjustments dependant on the refrigerants chosen, and the target temperature/capacity desired.

EDIT: Leaving out the Argon and substituting with proportional amounts of R23 and R14 will increase system heat load capacity considerably, although at the expense of coldest temperature achievable. Also keep in mind that including Argon in the charge blend, will very quickly raise the high-side running pressure of the system. So caution would be in order when doing so.

I hope this helps :D But please don't ask me for anything more specific beyond what I have already given on charge amounts in this post, since I am already treading on a thin line to disclose what I have.

maybe you should mention the size of the recovery tank mytekcontrols, pressure alone says nothing about the amount of gas unless you know the volume.

the autocascade 404power wants to build is that much different from a p100 that these figures could be 500% off, keep that in mind 404power. The only way to charge an autocascade imo is to look at the temperatures of heat exchangers, liquid lines and pressures. We use such small evaporators that the amount off r14 is lower then the amount you would expect in a "tube" evaporator. You can't build a car by only knowing that it has four tires. :D

for a real rough estimate of how much r14 you need, calculate how much liquid r14 would fit in the evaporator and buy that times 10 or something. :D

Thanks @ mytekcontrols & Unknown_road! :)

Anyway, as Unknown already said, my unit is totally different, I think your "rough" numbers help a lot! :D :) But unfortunaely I think that I will have to go fo r the way as Unknown explained:

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The only way to charge an autocascade imo is to look at the temperatures of heat exchangers, liquid lines and pressures.

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I hope that I can do it that way good enough! :)

@ mytekcontrols: Looking at my newest drawing (still aux + 2 stages + SLHX) ... which temps can you think of without Ethane (since it's still a 2-stager :))?
Because I don't know if that's good for me to try to build a 3 stager with so many gasses .... atm I'm already thinking of builing a smaller 2-stage auto-C with pipe-in-pipe HXs and a 1HP rotary first! :)

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Originally Posted by mytekcontrols

CAUTION... Do not run the compressor in a vacuum for more than 4-5 minutes, since heat build up in the motor windings will not have a way to escape in the rarified atmosphere.

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As you read about most of the builds here, you'll find that a majority of people tend to run their low-side pressures in vacuum. Cryo-tek was amazed by how many builds he saw which utilized this technique to achieve lower temps...although it seems to be common practice on the units phase units built for computers, it definately isn't ideal for the compressors :p:

we really push everything to it's maximum I geuss. :D

404power, I'll think about the cap tube sizing some more but some questions you can only really answer by building it and analyse the results.

Quote:

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Originally Posted by Unknown_road

maybe you should mention the size of the recovery tank mytekcontrols, pressure alone says nothing about the amount of gas unless you know the volume.

the autocascade 404power wants to build is that much different from a p100 that these figures could be 500% off, keep that in mind 404power. The only way to charge an autocascade imo is to look at the temperatures of heat exchangers, liquid lines and pressures. We use such small evaporators that the amount off r14 is lower then the amount you would expect in a "tube" evaporator. You can't build a car by only knowing that it has four tires. :D

for a real rough estimate of how much r14 you need, calculate how much liquid r14 would fit in the evaporator and buy that times 10 or something. :D

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Here...let me help you guys out with the info regarding my modified P100 ;) :

Charge: r123, r22, r23, r14.
#1 = 81" x .055
#2 = 90" x .042
#3 = 90" x .042
sub = 30" x .026
evap = 72"� x .031 x 2
(one captube per head)
Exp. tank= 30" x .026

Load, Inlet, head, out, suc/dis
0 w, -123c, -123c, -123c, 13/145
50 w, -121c, -121c, -121c, 15/175
100 w, -121c, -120c, -120c, 18/185
150 w, -119c, -117c, -116c, 20/200
200 w, 116c, -100c, - 112c, 23/225

Of course it's been tweaked from then, but at the time, the numbers were correct.....

Edit: By the way, this particular charge was done with NO ARGON ;)

@ s7e9h3n:

Thanks a lot! :) I think I will build 3/4 - 1HP rotary auto-c first and try to use these captube lengths! ;) I will go for one gigantic HX I think! :D ;)

EDIT: Drawing of my HX's (SRY but this is REALLY difficult to "paint" :D :():
http://img383.imageshack.us/img383/337/hxsbc1.th.png
(If really NOBODY is able to understand this strnage drawing, just ask! :))

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As Unknown_road suggested... maybe you should mention the size of the recovery tank mytekcontrols, pressure alone says nothing about the amount of gas unless you know the volume.

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I edited my original post, and have added both the Unit and Recovery Tank volumes. I also added a note about the judicious use of Argon.

s7e9h3n nice info on the cap tube sizes (better you then me on posting this information, since you never worked for Polycold ;) ) I forget what the CFM rating is on the P-100 compressor, but if I find it I'll be sure to post it, since I think this would be very beneficial in sizing 3 cascade system captubes based on the information you have already given.

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s7e9h3n stated... As you read about most of the builds here, you'll find that a majority of people tend to run their low-side pressures in vacuum. Cryo-tek was amazed by how many builds he saw which utilized this technique to achieve lower temps...although it seems to be common practice on the units phase units built for computers, it definately isn't ideal for the compressors

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Aside from the lack of compressor cooling this creates, it can also have a detrimental affect on system safety if even the smallest leak exists on the suction side circuit, especially considering the flammable nature of the refrigerants involved. Compression + Heat + Air (as in oxygen) is not a good mix with R290 or R600 :explode2:

Even if these conditions don't add up to an explosion, the combination of Compression + Heat + Air + Refrigerants = Acid = Compressor Burn-out = A Big Mess to clean up. This is also the reason that a good system design utilizes a low pressure electrical cut-out switch, in the event a leak is created down-the-road.

Although I understand that running in a vacuum may be necessary in traditional multi-compressor cascades, it is completely unnecessary when dealing with properly designed auto cascade systems that are sized appropriately for the load vs. temperature requirements.

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As I originally posted... CAUTION... Do not run the compressor in a vacuum for more than 4-5 minutes, since heat build up in the motor windings will not have a way to escape in the rarified atmosphere.

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I think it is important to note that this statement refers to using the compressor as a transfer pump, with the compressor suction valve front-seated, so as to cut it off from the normal flow coming back from the heat exchanger circuit. In this condition, and assuming that most of the gases have been pumped out of the attached Recovery Tank, we run the risk of having absolutely no mass flow through the compressor, and no gases surrounding the compressor's internal motor. Under these conditions (neither convection or conduction exist within this vacuum), the heat will build-up in the motor windings with no place to go , and eventually melt-down.

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404Power asked... Looking at my newest drawing (still aux + 2 stages + SLHX) ... which temps can you think of without Ethane (since it's still a 2-stager )?

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A 2 stager (auxiliary condenser + 2 cascades) should comfortably do -90C with only R23 and R14 as the low boiling components, and probably -100C with a Sub-Cooler (SLHX) attached. Of course heat load vs. system size will greatly influence your results. And one more thing that I haven't mentioned, but is oh so important, your performance will suffer if inadequate insulation is used (armaflex around the heat exchanger package will have tremendous losses as compared to polyurethane foam). Understandably you will want to prototype with an easily removed insulation, but in the final package you will need to commit to a closed cell hard foam insulation.

officially polyurethane is only rated down to -40 (celcius or farenheit doesn't matter in this case ). never had problems with that?

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Unknown_road asked... officially polyurethane is only rated down to -40 (celcius or farenheit doesn't matter in this case ). never had problems with that?

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The polyurethane foam I speak of has been used for years to insulate Polycold auto cascades which commonly operate down to -150C. I don't recall the company name or product number, but I'll see if I can dig up some info on it and post it later. I know at one time Polycold sold it in 1 gallon metal cans (Part A & B), which could be mixed together by hand, and then poured into the enclosure or cavity. Perhaps they still sell this re-foaming kit. If they do, this may be more economical then buying it direct from the source, which probably comes in much larger quantities only.

The self-expanding foam that they sell in the hardware and home improvement stores now-a-days doesn't work very well, and I've noticed that it wont cure properly in a sealed enclosure.

Mytek, do you think r1150 can be used if cold enough to let argon saturate?

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n00b 0f l337 asked... Mytek, do you think r1150 can be used if cold enough to let argon saturate?

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R1150 (Ethylene) with an atmospheric boiling point of -104C, places it 1/2 way between R23 (-82C) and R14 (-128C). It would seem logical that this might yield some improvement in heat load capacity for a system using these three low temperature components (R23, R1150, R14) at -120 to -125C.

As for your actual question, I really don't think I understand exactly what it is you are trying to say. As I stated, it would seem like there would be some benefit of using R1150, but this is not limited by having, or not having Argon in the system. Can you re-state your question in a different way that perhaps will make what you are after more clear?

Here is a thread discussing both Zeon and R1150 use: http://www.xtremesystems.org/forums/...ad.php?t=66141

Argon is normally said to begin saturating liquids at around -115C as far as I've read. R1150 boils at -104C, do you know if argon will still saturate even a little bit into a liquid in the -90C range. Ethylene is a much better gas for some to use because its much cheaper and easier to find then r14 which is incredibly expensive.

I'm also still trying to find a decent gas for around -70 to -80C that isnt incredibly pricey if anyone has any ideas.

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Originally Posted by n00b 0f l337

I'm also still trying to find a decent gas for around -70 to -80C that isnt incredibly pricey if anyone has any ideas.

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-70°C = Co2 = R744
-80°C = R23

Here in Germany 8,0kg R23 costs only 250€ . Whats your price in the USA?

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Originally Posted by mytekcontrols

The polyurethane foam I speak of has been used for years to insulate Polycold auto cascades which commonly operate down to -150C. I don't recall the company name or product number, but I'll see if I can dig up some info on it and post it later. I know at one time Polycold sold it in 1 gallon metal cans (Part A & B), which could be mixed together by hand, and then poured into the enclosure or cavity. Perhaps they still sell this re-foaming kit. If they do, this may be more economical then buying it direct from the source, which probably comes in much larger quantities only.

The self-expanding foam that they sell in the hardware and home improvement stores now-a-days doesn't work very well, and I've noticed that it wont cure properly in a sealed enclosure.

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You should see Cryo-tek's "foamer"....no hand mixing required if I remember correctly....the machine does the mixing for you :woot:

Co2 = dry ice
r23 = pricey

What about Ethane NoL, or is that too expensive? I was told in the UK it's a similar price to Ethylene :( .

Hmmm around here its $35 a lb but I need to find a place to get it, it might be a very good alternative after all.

here in austria:

R23: 8kg - 260€
R170: 10L bottle, 200bar, 99.5% - 260€
R744: 10kg - 23€

Yeah and you can never buy a small quantity sadly :(

yes i hate that too! otherwise i would get hold of 2kg R23 and a bit R14!

I think this is the main problem with these designs. Who is going to whip out 500 euros to buy 3 tanks of quite pricey refrigerants to experiment with?

Im just about to try an autocascade but Im using what I have here, R23 + Propane. I have R402, R404a and R22 also but hear from Luke that he finds Propane works the best in a normal 2 stager.

Any suggestions on what I have? Compressor is 1hp R410a Rotary with matching condensor.

Noob, luckilly R23 is pretty cheap over here. Jin tells me that in the US its the most expensive. Over here R116 is rediculously expensive. Over in the US R116 is cheap.

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Originally Posted by n00b 0f l337

Co2 = dry ice
r23 = pricey

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No Dry ice problems while using Co2 when you will have good amount of co2/propane inside system.

another way to prevent dry ice problems is using second captube to evap, with liquid propane. It will flush dry ice from evap.

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Originally Posted by johann

I think this is the main problem with these designs. Who is going to whip out 500 euros to buy 3 tanks of quite pricey refrigerants to experiment with?

Im just about to try an autocascade but Im using what I have here, R23 + Propane. I have R402, R404a and R22 also but hear from Luke that he finds Propane works the best in a normal 2 stager.

Any suggestions on what I have? Compressor is 1hp R410a Rotary with matching condensor.

Noob, luckilly R23 is pretty cheap over here. Jin tells me that in the US its the most expensive. Over here R116 is rediculously expensive. Over in the US R116 is cheap.

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add a stage with r600 or something to "purify" the r290 from the r23 before it condenses.

@godmod, r170 is a liquid in the bottle so it isn't 200bar. (might be helpfull to calculate how much ethane really is in the bottle.)

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Over in the US R116 is cheap.

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At first glance R116 looks like a good substitute for R23:

R116 boiling point = -79C
R23 boiling point = -82C

However its freezing point needs to be taken into consideration if you plan on building a system to run much colder then -90C:

R116 feezes at -94C
R23 freezes at -155C

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Argon is normally said to begin saturating liquids at around -115C as far as I've read. R1150 boils at -104C, do you know if argon will still saturate even a little bit into a liquid in the -90C range. Ethylene is a much better gas for some to use because its much cheaper and easier to find then r14 which is incredibly expensive.

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Very good question. I suspect that some argon would dissolve into R1150 at the temperatures you described, but it wont be much, and therefore the percentage used as part of your charge should be very small. Adding too much will simply raise your compressor's discharge pressure, without adding any appreciable performance benefit.

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You should see Cryo-tek's "foamer"....no hand mixing required if I remember correctly....the machine does the mixing for you

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If it's what I think it is, it certainly wouldn't be in the price range for the occasional user :eek: But if a person is doing a lot of chiller production, having a spray foam machine is the only way to go.

At the place I occasionally do contract repair work on used Polycold units, they have a system as you described which is provided by a company called InstaPak.

So r116 has similar problems to that of co2, hmmmm...
I wish these suppliers would sell smaller quantities!

Hi there @ all! ;)

New drawing of my first auto-c .... I hope it'll work! :D
A few parts are already here @ my place, others will be here in the next weeks! :)

http://img179.imageshack.us/img179/5949/planyo1.png

regards
-404

EDIT: Can I also use a SMALL shot of R740? What do you think? :)

As far as I know the AE1420Z has only 1/2HP

And why not run the subcooler inline with the evap to receive flow in an inline fashion?

You will got problems with that compressor, for sure rotarys are the best for autocascades...

With that aspera it could not hold any load

@ cold_ice: CAE2420Z (as far as I know = same model) : motor power = 547W
That would be more than 1/2 HP I think! ^^ :)

@ noob: I don't know what you mean for sure but I THINK you mean it that way? :D

http://img120.imageshack.us/img120/6770/planww0.png

(cap @ sub-cooler is wrong!!)

@ LukeXE: Why do you think so? In s7e's auto-C, there is also a L'Unité comp used (NO rotary!) ^^ :)
But I can also get small R134a rotarys with ~ 1/2HP @ 50Euros each! ^^ :)

I think that because I tried two times with that kind of compressors (more than 1/2HP) and still no succes. Idle temperature was OK, but load...better results on normal SS...

But try, try, maybe your unit will finally work, I hope !

for autocascades big displacement compressors are a big plus it doesn't really matter what kind of compressor it is.

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(cap @ sub-cooler is wrong!!)

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Yes I agree with this observation. Basically you need to reverse the orientation of the "Evap Return" connection and the subcooler captube. So... in other words, you need the subcooler captube to feed into the suction side at the top of the subcooler heat exchanger, and the "Evap Return" to tee into the suction between the bottom of the subcooler, and the top of the cascade. Remember the subcooler only works if it is isolated and doesn't directly see the heated gases returning from the Evap.

you could also just cancel the subcooler cap tube and make the cap tube to the evap a little shorter so that you get floodback from the evap into the subcooler.

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Originally Posted by mytekcontrols

Remember the subcooler only works if it is isolated and doesn't directly see the heated gases returning from the Evap.

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can you explain a bit more? i got a bit comfused :)

@ mytek:

Do you mean it that way? :)

http://img179.imageshack.us/img179/5949/planyo1.png

Yeah he does I didnt even think of that it might want to avoid heated gas from the evap, but that seems 100% logical!

Actually I was thinking of something like this.