I think cryo-tek has discussed over 2500watts of heat on multi-stage autocascades. :)
EDIT: What length capillary though for the wierd tube?
Printable View
I think cryo-tek has discussed over 2500watts of heat on multi-stage autocascades. :)
EDIT: What length capillary though for the wierd tube?
I've spoken to cryo-tek and he tells me it's possible to build a 5hp autocascade capable of removing (iirc) 1500W of heat the size of my polycold - basically the size of a large stereo cabinet :eek:Quote:
Originally Posted by Nyx
Nyx, The load is half of the question, the second half of the question gives the desired temperature.Quote:
Originally Posted by Nyx
500 watts at –100c could be done with about 3 hp compressor. But if you want –130, that could take a 5 hp compressor.
How big you asked. Do you want to build it with Tube in shell or flatplate heat exchangers? I think that a tube in shell, 3 stage autocascade for a 3 hp compressor could fit into a 2-foot cube with working room. A flatplate heatexchanger would fit in half that. Swep makes some nice flatplate heatexchangers if you want to spend the money.
There are companies that make 5 hp units that are the size of a home refrigerator. One company makes a system that is the size of a small refrigerator that uses 2 Copeland ZF33 scrolls. This thing can handle over 3500 watts. Did you ask your self the second half of the question? At what temperature? They do 3500 watts at around the –120c range. I know someone’s reading this and asking “is that at the inlet or outlet of the evaporator?” They tend to use an average of the inlet and the outlet with a maximum delta.
Choosing your refrigerant is a topic for its own thread. Am I rambling? Sorry, it’s cold here and there’s no one to talk cryo with.
I like wet jacket style exchangers personally :) remind me of the good ol camp days, but I definitely want to get a hold of a plat exchanger for experimenting purposes.
1 Word IMPRESSIVE :eek2: !!!!!
I am really lost for words. Except to say YOU ARE XTREME......
The evaporators we use on the systems we build here are rather small compared to the phase systems that the companies you mentioned use. As it has to fit the CPU head of the computer.Quote:
Originally Posted by cryo-tek
What are your thoughts about using such small evaps on Auto-Cs ?
Heres an example of a CPU evaporator :D
http://helderfonseca.planetaclix.pt/...ev3/vapo01.jpg
cryo-tek you really should show us some pics, i love autoC's.
their a pain to build though with smaller compressors.
Now that’s a nice piece. :) How big is this? Small evaporators are fine if there is enough surface area to remove the heat load. You have the same issues with a traditional cascade. Man that’s nice!!Quote:
Originally Posted by Blaster
I assume that there is another hole in the top for the return and a Cu sleeve.
ya that is definatly the best designed block I've seen, loads of surface area.
First I need to get the pictures from the camera to my computer then figuer out how to post them. DON’T LAUGH !:nono: I’m only an Autocascade Geek. Soon!Quote:
Originally Posted by kayl
kayl, I think I did it:banana: I started a thread and posted some pictures of a 2 stage autocascade that I'm putting in an old test chamber. I want to do some cryo treating of steel bits and blades.Quote:
Originally Posted by kayl
Theres many nice evap designs more or less like this one, i do try to increase surface area with the grooves.Quote:
Originally Posted by cryo-tek
cap tube is drilled from top till base and a Cu sleeve is brazed. Dimensions are 40mm diameter, 33mm height. So the surface are in contact with cpu head is about 12cm^2
Quote:
Originally Posted by cryo-tek
thanxs man. we love cold things here also:toast:
Block Assembly... Original..
Quote:
Originally Posted by chilly1
And there is the best one.
To add some clarification to what cryo-tek has proposed in his earlier piping schematic, I offer the following additional information:
Cap Tube Phase Separation Overview
http://www.xtremesystems.org/forums/...1&d=1168114066
In the diagram above, a method is presented by which partial phase separation is achieved through creating a "back-up" or restricted area immediately following a cap tube soldered into the discharge line within a tube-in-tube heat exchanger.
Cap Tube Separation Detail
http://www.xtremesystems.org/forums/...1&d=1168114197
When the two phase refrigerant flowing through the discharge line of the heat exchanger encounters the restricted area formed by a combination of the pinch point in the tubing, and the body of the cap tube. A back wash occurs as the liquid part of the refrigerant mix trys to squeeze through. Some of the liquid refrigerant bounces backwards and/or builds up, thus feeding the cap tube.
Advantages to such a system:
- Greatly simplified construction
- No phase separators required
- Single inner & outer tube creates multi-stage autocascade
- Heat exchanger can be used as interconnecting line between condensing unit and evaporator
- Lends itself to creating a very small package
By having the captube live within the suction side tube of the heat exchanger, the cap tube automatically gets sub-cooled by the expanding refrigerant returning from the evaporator and succeeding stages. To improve performance of the system, additional captube separators may be required as compared to a system that utilizes actual phase separators between heat exchangers.
This idea is based on an actual product that was produced in the 80's by a company called Polycold Systems, and utilized a mixture of R-11, R-13 (CFC's), and was later abandoned when they encountered difficulty in creating an HFC replacement charge. Although the design was patented, this has long since run out its 17 year period. The product was called a P-20, and utilized the "serial" heat exchanger as a bendable armaflex covered line connecting the condensing unit to the evaporator.
I was involved in the development of the original P-20 proto-type, and can attest that the system worked quite well, achieving temperatures down to about -80C (low load) and -65C under 200 watts. The P-20 was based on a 3 cap tube design similar to what cryo-tek showed in his last piping schematic.
I'm sure that with a little bit of experimentation, this design could be made to work with a combination of perhaps R-22, R-123, and R-23. And if oil problems are encountered, adding an oil separator to the condensing unit, or the addition of some propane would probably cure it.
Hi Mytek, you seem very knowledgeable as was Cryo-tek. I hope you like the forum here and stick around and hopefully are not scared off by any members of this forum. I hope to try the method you listed above when Cryo-tek first explained it to me, but i haven't gotten around to it just yet. The biggest problem i cannot figure out is proper length of capillary tubing for the design. Do you know of any formula's or methods to calculate the capillary length in a system like this?
Hi n00b,Quote:
Do you know of any formula's or methods to calculate the capillary length in a system like this?
Unfortunately I have been away from doing actual design on this stuff for so long now (20 years) that I don't recall the flow calculations that were used. Also I must admit that on several designs intuitive guesses were more the order of the day (I never was especially good with math). When I was deeply immersed in cryo system development, it almost seemed like I had a 6th sense about what would or would not work. Of course I am pretty certain that I wasn't the only one that approached this stuff in this way (just ask cryo-tek;) ).
Cryo-tek is still very much tuned into this stuff, so I'm sure he could give you some insight on this as well.
Sorry I couldn't provide a more specific answer to your question.
Cryo-tek unfortunately does not seem to visit XS anymore, he was scared away by some members on this forum.
Hmmm... That doesn't seem like him. To be scared away from sharing his knowledge that is (I worked with him back in the P-20 days and beyond... really great guy, went out of his way to help anyone).Quote:
Cryo-tek unfortunately does not seem to visit XS anymore, he was scared away by some members on this forum.
So what happened?
Eh its a bit unknown but can be seen in his threads that he was doubted and criticized heavily. Most likely this post even will be deleted for being off topic, but your private messaging function doesnt seem to be enabled. I'd really like to learn more of what you know though :)
Hey Michael,Quote:
Originally Posted by mytekcontrols
Welcome to Xtremesystems :toast: I think I'd only need one guess to figure out your relationship with Cryo-tek :p: Just a FYI....Cryo-tek was never "scared" off the forums. If you want to know the REAL story, drop me a PM (private message) and I'll be happy to explain. For obvious reasons, it's just better that we keep any personal info of his private. By the way, in case you haven't made the connection, it was my Polycold unit which he worked on ;) http://www.xtremesystems.org/forums/...ad.php?t=97265
Not really into IM's or PM's, but if you check out my profile, you'll see a link to my website, from there just click on Contact and send me a General Inquiry message. I'll respond from my personal email account, and we can continue this conversation (I probably won't respond today, got some stuff to do, but get back to you soon).
I,m the one who questioned cryo-tec knowledge, as he never posted anything but auto cascade designs, even that he was asked to post pictures or answerers to very specific questions. Those design drawings have been available for 15 years or more. He did post the above picture of his work, the one above using fiberglass insulation. That told me he knew very little about thermodynamics or cooling in general. As moisture will pass right thru the fiberglass insulation.A professional working in cryogenic cooling would not do work like that,especially since it would be so detrimental to the outcome,you would lose much of your capacity. It sure doesn't look like the work from a professional to me.
ps: where the crimp is,that would cause a Bernoulli effect, flow would temporally speed up,while the pressure would drop in that area.
He wasn't scared I'd wager royaly pi*sed at one who was scared to have a compeating knowledge to him self so acted like an A*s towards him. Rather then treating him on an equal level acted condecending (at least the un named member seems to be good at condicending)Quote:
Originally Posted by mytekcontrols
Or so How I viewed the whole drama.
As cryo-tek said in the other thread, the fiberglass was used as a *gasp* temporary insulation so that if he had to make any changes before it was finalized, he wouldnt have to deal with tearing apart something that was cast in foam.
Quote:
Originally Posted by Xeon th MG Pony
He was posting BS any you guys believed him.
wdrzal signed :Walt DrzalQuote:
( at least the un named member seems to be good at condescending)
ps so much for unnamed member,I have nothing to hide. "almost" any dummy could have figured that one out.:rolleyes:
Any time I see a severe safety violation or someone posting BS,yes I do challenge them,in public because many thousands will read these threads. There is already way to many "ideas" posted as they are tested working fact when they are mostly BS..
Nothing wrong with a public debate, the correct person can always prove what he is saying. I very rarely give a answer without a explanation of "why or how" Most is from memory ,so I may make a mistake or two ,but if I do ,I'll apologize for the mistake. I don't have the time to look up and verify every thing I post.
Many here just post but never say how they arrived to that conclusion.:fact:
I will say this again -
I hope you guys have gotten this out of your systems. It would much better for all if you could take care of your disagreements in private. I am asking each of you to please put and end to this public bickering. There is a place here for all of us. I don't want to see any empty seats.;)
thanks
To quote wdrzal:
First I would just like to say, I am a very new member to this forum, and have found it to be an incredible resource and an inspiration. I like cryo-tek, have 20+ years under my belt working with autocascade systems (more than half of which was in the R&D aspect). At the place I was doing this work, we would always use fiberglass insulation for the initial tests on a new cascade design, just to see if we were in the ball park, and to catch any accidentally plugged cap tubes. In order to avoid the inevitable intrusion of water vapor as was expressed in the wdrzal's comment above, the entire fiberglass insulated heat exchanger would be carefully wrapped and sealed in a plastic bag. In fact we got so good at this, that many times we would only see about a 5% to 10% reduction in performance, as compared to when the cascade was later polyurethane insulated.Quote:
He did post the above picture of his work, the one above using fiberglass insulation. That told me he knew very little about thermodynamics or cooling in general. As moisture will pass right thru the fiberglass insulation.
wdrzal it is good that you question things, and are not willing to accept something just because others do. This is where true innovation comes from. This is also what I had to do when working for Polycold, in order for the P-20 (as well as other designs) to become a reality. If I hadn't questioned and persisted in my desire to test out what my boss thought was an unworkable design, we wouldn't have achieved the break through that it was. However I also had my share of being too stubborn to see beyond what I had grown used to, and also found myself being critical of other peoples ways of doing things. Just remember that things are not always as they seem on the surface.
To quote wdrzal:
This is an easy one to answer. Cryo-tek's main experience has been in auto cascade design (30 years to the present). So this is the reason why he probably only feels comfortable to express knowledge in this area. As for posting pictures, cryo-tek himself admitted that he wasn't any where as good with computers as he was with auto cascade design, and was intitially struggling to figure out how to do this. Also I have known cryo-tek for many years, and know that he is an extremely busy guy, so much so, that I am amazed that he even found the time to participate as much as he did in this forum. I'm sure if he didn't answer specific questions, it was not that he didn't want to, but more that he had a billion other things going on in the background.Quote:
I,m the one who questioned cryo-tec knowledge, as he never posted anything but auto cascade designs, even that he was asked to post pictures or answerers to very specific questions.
To quote runmc:
I totally agree, and will say no more on this subject:clap:Quote:
I hope you guys have gotten this out of your systems. It would much better for all if you could take care of your disagreements in private. I am asking each of you to please put and end to this public bickering. There is a place here for all of us. I don't want to see any empty seats.
I think wdrzal, me and some other don't have a problem with cryo-tek at all we were just curious and ask him a lot of questions because we wan't to learn. If he doesn't have the time or the knowledge that's no problem. Some other members here made it a problem by saying we shouldn't bother him and were defending hem constantly, I don't know him but I think he is a grown man and can take care of himself. what happend is so exaggerated by some people, saying he is scared away without even knowing what happend etc. according to stephen this isn't what happend so.
Having a discussion is healthy and shouldn't be seen as scare tactics.
But it really creates a negative atmosphere around here(I come here less and less because of this), and I hope we can all act like grown ups and stop flaming and making stuff up. So we can all get allong with each other and get the good atmosphere back. Let's all have fun building awesome cooling systems and try to learn a lot in the process. Don't have bad feelings towards each other, it's bad for your blood pressure. :)
I'll give it one more try to expand my knowlegde by asking a question to mytekcontrols, not trying to scare him away :D (sorry I have to make a little bit fun about it)
@mytekcontrols: when cryo-tek was refilling the autocascade he had r14 and argon in the mixture, the argon couldn't condens according to a pt-chart but it gave a significant temperature drop. Do you know why this happens?
You are correct that the Argon will not condense at these temperatures and pressures. What it does do is to go into solution with the R-14. Or more correctly stated, some of the Argon gas goes into solution with the R-14 liquid. This creates a new refrigerant in a sense, something that when evaporated, will yield a temperature somewhere between R-14 and Argon. The colder, or more sub-cooled the R-14 is, the more Argon gas will be dissolved into it, and the colder will be the evaporated temperature. This also applys to almost any 2 or more refrigerants that are being sub-cooled within an auto cascade. Just to be clear... what I mean by sub-cooling is, when the conditions exist that are beyond that which is required to liquify a given refrigerant. So for instance if you have R-22 circulating in a part of a heat exchanger that is colder and higher in pressure than what is minimally required to 100% liquify the R-22, but not of the correct conditions to liquify R-23, you will see some of the R-23 go into solution with the sub-cooled R-22. Later when this is expanded downstream, you will achieve a temperature colder than R-22 alone.Quote:
when cryo-tek was refilling the autocascade he had r14 and argon in the mixture, the argon couldn't condens according to a pt-chart but it gave a significant temperature drop. Do you know why this happens?
This is what really makes auto cascades superior to multi-compressor systems.
I hope that answers the question :)
wow, thats a nice answer. i always wanted to know exactly this! thank you for that explaination :clap:Quote:
Originally Posted by mytekcontrols
Unknown_road, its the same with me. these endless OT debates make me so tired!
Can you answer me a question?Quote:
Originally Posted by mytekcontrols
How do you separate the liquid refrigerant and the gas (e.g. R22/R23)?
Do you build your own phase seperator (if yes, how?) or do you buy oil seperators and use them? I saw some Temprite 340 in Cyro-Teks pictures... so they work as a phase sep?
Next question:
Is a suction line heat exchanger really needed in front of the first phase separator?
Thank you VERY much!!
:clap: :woot:
PS: Sorry for my crappy english...
Moc your english is better then you think, we can understand you 90% of the time :)
thanks for that answer :)
mytekcontrols -
We welcome you to XtremeSystems.:welcome: I along with many others here are glad to have you here along with your brain. :D Thank you for helping us along with the auto-cascade. :surf:
few goot links i found.
I wish we could of seen more of his stuff.
http://www.xtremesystems.org/forums/...&postcount=282
http://www.xtremesystems.org/forums/...&postcount=273
http://www.xtremesystems.org/forums/...&postcount=248
http://www.xtremesystems.org/forums/...&postcount=205
the guy did give us some stuff :toast:
but i guess i understand some one whos not that much into computers not post regularly
im sure he has his reasons.
s7e9h3n i sure would love to see some pics of this benching
Ohhh...but you have....;)Quote:
Originally Posted by kayl
2 Intels tested = 2 World records:
http://www.xtremesystems.org/forums/...d.php?t=102900
http://www.xtremesystems.org/forums/...postcount=2260
1 AMD tested = 1 Frozen A$$ mobo:
No matter what I did, my DFI would always shut off @ -73C in bios. Never ended up booting into windows :( . IIRC, this is @ ~1.6-1.7V on a non-bugged AMD X2....
http://img90.imageshack.us/img90/3252/724mo.jpg
Some more mobo fun :p: :
http://www.xtremesystems.org/forums/...d.php?t=102026
And YES, I'll test it on a x6800 Conroe when a special "care package" arrives for me this week.....
And YES, I'm hoping to run a dually setup in the near future as soon as I get a pair (or two) of "new ;) " cpu's from AMD....
That autocascade of yours looks awesome s7e9h3n!
Can you give us some more details about the unit? I.e. compressor, condenser, final gas mix etc? I don't think they were ever posted in the build thread :rolleyes: .
I totally agree with ya! :)Quote:
Originally Posted by runmc
I'm rly one of the guys who are RLY happy that there is someone, who understands what he is doing @ autocascades, again! :D :)
@ mytekcontrols:
BIG THX to you for your "R14 + Argon" explanation! :clap: But it would be rly nice if you can apply your PM-function! If you dont want to, I have to respect your decision and I don't will aks again of course! :) I just would be rly thankful for a lil help @ building my own autocascade because I'm completely new in this business ... and unfortunaley I don't have any experiences in this yet! :( So I need someone to teach me! :D
Please let me know if you r willing to help some of us here @ XS @ building ur owns! :D But one thing for sure: BIG THX for your explanations 'til now ... you already gave us a big PLUS in our knowledge about auto-c's! :)
Thx a lot! ;)
regards
-404
Moc asked:
Basically what you need is:Quote:
How do you separate the liquid refrigerant and the gas (e.g. R22/R23)?
Do you build your own phase seperator (if yes, how?) or do you buy oil seperators and use them? I saw some Temprite 340 in Cyro-Teks pictures... so they work as a phase sep?
A small cylinder where the 2 phase (liquid/gas) mixture enters the side, preferably at an angle to impart a centrifugal effect (this last part aids in separation of the liquid from the gas), a gas exit out the top, and a liquid exit out the bottom. A Temprite will also work, assuming that it does not have a float valve for the liquid to exit (continuous flow), or if it does have a float, seal off the original liquid return and drill a hole centered in the bottom for your new return.
I have also seen people using old MAPP or Propane cylinders, however do be careful that you don't exceed the working pressure of these thin walled steel cylinders (remember you will be on the high pressure side of the system).
Adding steel or copper wool in the upper section will also improve the separation efficiency, as well as increasing the volume of the separator (the bigger the volume, the slower will be the velocity imparted, and the more readily the heavier liquid will tend to fall towards the bottom).
Moc also asked:
Yes it really helps decrease the temperature entering this first phase separator. Without it, you will be entering the phase separator at essentially room temperature. With it, and depending on your refrigerant mixture (and other factors), you can probably see a temperature of -25 to -30C. Since this first heat exchanger acts more like an economizer, you get this added cooling essentially for free, adding only a small amount of pressure drop in the process.Quote:
Is a suction line heat exchanger really needed in front of the first phase separator?
I hope that answers your questions Moc.
No offens but it looks like an alfabits soup factery exploded! rly, r, THX??Quote:
Originally Posted by 404Power
Some kind of new exchanger? I think it would be apt if one left the abreviations to the devices of which they belong to avoid confution. Thank you (Ps miss spell all you want, but for the love of mythology please use the word properly! So I and mycryocontrols can under stand you!)
It does! Thanks for your detailed answer!Quote:
Originally Posted by mytekcontrols
Here are some schematics I drew starting with a very basic auto cascade, and then evolving into a system capable of -160C (or colder).
Basic Auto Cascade
http://www.xtremesystems.org/forums/...1&d=1168279227
Two Cascade System
http://www.xtremesystems.org/forums/...1&d=1168279227
Three Cascade System
http://www.xtremesystems.org/forums/...1&d=1168279227
Three Cascade w/Sub-Cooler
http://www.xtremesystems.org/forums/...1&d=1168279227
This last system will work well with a R-22, R-123, Ethane, R-23, R-14, Argon mixture. The Sub-Cooler allows for the Argon to really do its stuff, dissolving into the sub cooled R-14.
Sub-Cooler description:
As can be seen in the diagram above, the outlet of the Sub-Cooler feeds 2 cap tubes. The flow ratio is 1/3 vs. 2/3, with the 2/3 flow feeding the evaporator, and the smaller 1/3 flow cap tube feeding back into the subcooler. Since the Sub-Cooler is bypassed on the return (suction side) return from the evaporator, it will run at a colder temperature than the final cascade under loaded conditions. I know this probably looks strange to some, but believe me when I say it really does do the trick.
Remember when experimenting with the sizing of the Sub-Cooler to keep it on the small side as compared to the final cascade. The suction volume requirements are going to be very small.
And thank you everyone for welcoming me to this forum:banana:
:D Yes that really is strange !Quote:
Originally Posted by mytekcontrols
Do you recommend plate heatexchanger or coax? I think if the size of the suction side have to be smal plate hx are better?
Do you think instead of R22 propane would also go?
Next important question:
Why do you use R-123? It boils @ around 27C... my room is always colder than that...:p:
open up a topic or ask your questions here so everybody can participate and make the knowledge public! else everybody ask questions one by one when you post it here everybody can read or use the search later to look up the info.Quote:
Originally Posted by 404Power
Thanks for the wonderful info mytek! Now, maybe people will begin to understand why Cryo-tek was such an asset to this community. Yes, there's quite a lot of information regarding autocascades to be found, but there are only a HANDFUL of people (such as yourself and Cryo-tek) who actually can APPLY this information. Get ready to be overwhelmed with questions :p: !Quote:
Originally Posted by mytekcontrols
Plate Heat Exchangers are very efficient, but for small systems can be very expensive. When building a system with 1-2hp or less, tube-in-tube construction is inexpensive and still works quite well.Quote:
Do you recommend plate heatexchanger or coax? I think if the size of the suction side have to be smal plate hx are better?
I don't recall the exact boiling points on these 2 refrigerants, but if my memory serves me correct, I do believe either one would do the trick. Just be carefull that your overall mixture doesn't get too heavy in flammable components for safety's sake. Also remember that a leak in the mid to upper stages could result in the flammable component being more pure, and separated from the non-flammable gases, there-by being explosive even when the mixture is not.Quote:
Do you think instead of R22 propane would also go?
R-123 aids the heat exchange in the air-cooled condesnser, improves compressor cooling, and acts as a very good sponge for some of the lower boiling refrigerants to dissolve into, which yields some colder temperatures in the first stages when evaporated. Remember this is the key to making auto cascades really do their stuff.Quote:
Why do you use R-123? It boils @ around 27C... my room is always colder than that...
You can't always base your refrigerant selections strictly on pressure vs. temperature charts when it come to auto cascades, there is a bit of magic, or should I say intuition derived from lots of trial and error experiments in order to finalize the mix. Basically any time you mix more then 2 refrigerants together, it becomes nearly impossible to calculate through mathamatical means what is really going to happen. Although I did know one guy that had somehow figured it out, wrote a program, and then wouldn't share the techinique (too bad for everyone else).
OK ... I'm sorry .... didn't know that words like rly, thx and so on are that unintelligible for the most of you! I'm sorry! ;) Will try to write in perfect English in future! :)Quote:
Originally Posted by Xeon th MG Pony
@ Unknown_road:
I totally agree with you! :)
But do you think that really all questions are that important and interesting for all people here @ XS.org? :) No offens but I just think that questions which only go hand in hand with only ONE specific auto-c, aren't that interessting for all of you ... but if I have further questions I will open a new thread, K? :)
regards
-404
Ya the R14+argon is as I suspected, but a confirmations nice.
Yep, I've tried to explain it before as Cryo-tek had explained it to me, but I just sounded dumb while doing that......:p:Quote:
Originally Posted by n00b 0f l337
I worked it out actually with a Chemistry professor I know, talked with Jinu as well when I figured it out and also told Ricky.
Doen't need perfect just understandable mate ;)Quote:
Originally Posted by 404Power
I'm interested in seeing how they've applied that knowledge.....Quote:
Originally Posted by n00b 0f l337
O.T. - Jin...when you catch this post -> CALL ME...
Jin doesnt have r14, and Ricky maybe using it in the third stage of his 3 staer.
If we :kissbutt: and give him a :buddies: do you think cryotek will visit us again? :D
Hmm those designs also look close to what I talked alot with LukeXE about, basically a aux condenser and a subcooler is needed with a very very low pressure refrigerant to work well.
I'll give him a call later ;)Quote:
Originally Posted by runmc
I see ... no problem! :D :)Quote:
Originally Posted by Xeon th MG Pony
Ummm....cryo-tek had already explained such an autocascade. Mytek just made it bit more clear :p:Quote:
Originally Posted by n00b 0f l337
Yeah but I'm stating that although cryo-tek is incredibly valuable, these designs are "basic" autocascades and are already pretty easy to figure out.
OK .. I'll post my design @ this thread for now! :) If this is not OK, please tell me and I will open a new thread! :) Just want to ask some general questions ... if I have some specific questions @ my auto-c, I'll open a new thread! K? :)
http://img412.imageshack.us/img412/1...lannew2cf6.png
1.) question I wanted to ask:
Do you think a oil-sep is needed in this unit? I already asked a few people ... 50% told me YES, 50% No! :D ... so don't know! Would like to here the opinion of an expert! :)
2.) Sorry to ask this "dumb" question but I really don't lnow what you mean by the term "Aux-condenser"!? :(
3.) ... to be continued ...
TIA for all your answers for now! :)
regards
-404
1) Yes, simply becuase phase seps wont capture all the oil with the first stage refrigerant.
2) An auxillary condenser is generally a refrigreant with a boiling point close to or a bit less than the ambient temperature, it acts almost as if its another condenser.
3) Go on ;)
As for your diagram, the first plate hx would be your auxillary condenser if you add an auxillary refrigerant, (like the r600 might work)
No dumb answers (unless you've already been given the answer multiple times:slapass: ). I use the term "Aux-Condenser" (short for Auxiliary-Condenser) mainly because this is the way it was taught to me. Although it does make sense in a way, since it follows the primary condenser (which is shown as air cooled in the diagram), and doesn't have any kind of cap tube or expansion valve feeding it (unlike the Cascade-Condensers). Essentially it continues the condensing process initiated by the primary condenser, by utilizing the cool gases returning from the upper stages. I know it is technically a heat exchanger.Quote:
Sorry to ask this "dumb" question but I really don't lnow what you mean by the term "Aux-condenser"!?
On face value I would say it does, assuming that R290 and R660a 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.Quote:
Do you think a oil-sep is needed in this unit? I already asked a few people ... 50% told me YES, 50% No!
Also be sure to use Zerol 150 or similar for your compressor oil, since this has a lower freezing point than conventional compressor oil.
BTW nice 3 cascade design with subcooler, and nice drawing to boot:clap:
Nice drawings there 404Power. What is the purpose for the second solenoid valve after the first phase separator and the second plated HX?
OK .. no more dumb questions! :D ... anyway Thanks a lot! :)
@ oil (-sep):
If I'm right know, I think that both, R290 and R600a, a really good oil-transporters! :D So ... if I understand your post correctly, you mean that if I use at least one refrigerant that is a great solvent for oil, I can leave out the oil-sep + the first solenoid valve and make a direct connection between bottom of the first phase-sep and the suction line? Am I correct? :)
... and ... Thanks for your nice words @ my design/drawing! :)
regards
-404
EDIT:Thanks! :) As I know, it really helps a lot to shorten the cool-down-process in the first minutes after starting the auto-c! :) First, you keep it closed! ... a few minutes after booting-up, you open it to disengage the way to the whole auto-c (sry, but I had a few problems now to explain this in English! :()Quote:
Originally Posted by marru
Yes, i kind of had that comming but i was not sure. I guess with a 3 stage autocascade that little valve is a must. It reduces the transitory period significantly. Thx.Quote:
Originally Posted by 404Power
Yes R-290 is a VERY good oil carrier!, to the point that to use it you usually need a slightly more viscus oil for good lubrication.
Thanks for your reply! ;) :) I'll edit my diagramm in a few minutes! :DQuote:
Originally Posted by Xeon th MG Pony
EDIT: POST UPDATED!
Hey Mytekcontrols!
1)What type of compressor do you recommend me? A nice rotary, a normal hermetic compressor like Danfoss SC** or a scroll?
2) If I would use R22 as my "first" refrigerant, is it possible to use a TXV? I think and saw in cyro-teks picture only captube...
Thanks for answer ;) !
Welcome to XS mytekcontrols!
I along with lots of other members, are very happy to have someone like you in the forums! It would be great if we could have cryo-tek back too :D!
I also have a question... what other refrigerants are there like R-123 that boil at room temperatures?
Thanks,
Brett
R-11 if I recall correctly banned through out most of the 1st world nations but still availible in the US.
I've got a pair of solenoids installed on my auto.....While they do help in "pull-down" times for the unit, the greatest benefit I get from them is the ability to switch each of the evaps on/off. I recently powered up the auto to see if it was still working well.....needless to say, it's still running perfect. After giving the unit about 20-30minutes to warm up, I hit the switch for the solenoid and temps go from ~+20C -> ~-110C in approx. 1 minute flat :cool:Quote:
Originally Posted by marru
Beautiful s7, yeah I like solenoids for that too.
@Xeon, I got a can of r11 (14 lbs) not a drum, a can. That I picked up just for Aux condenser purposes.
Ah well you're in the states, so It is I'm sure more availible, as far as I'm aware it is compleatly banned in Canada, UK, Europ in general.
Heh easy to find yes, but only in 100lb drums as far as I've seen.
When I do my autocascade I'm using a Danfoss sc12mlx, and running r11, r134a, co2, r1150 if I can get some ethylene and avoid co2 problems.
Won't it be quite difficult to go r134 -> r744?Quote:
Originally Posted by n00b 0f l337
OT: Spoke with Cryo-tek earlier today. He says he'll try his best to stop by and see the recent happenings. He's been swamped at work and it's sounding like he may even be MORE busy in the coming weeks. Good for him and his business :clap: , bad for us and our autocascades :(
Nope because they generally use r134a to condense r508a. And then the r508a will help as well.
Yes R-11 was good stuff:toast: Even better was R-114 (also banned). Heck back in the CFC days you could get by with 4 refrigerants and easily achieve -150C or better. The charge: R-114, R-13, R-14, Argon. The HCFC replacement was as I described earlier R-22, R-123 (replaces R-114) R-23, Ethane (replaces R-13) R-14, Argon. The HFC only version gets even more complicated, and also requires POE oil as well as a very good oil separator. Of course if you don't mind using flammable gases you can still get away with a less finicky oil, and probably eliminate the oil separator, since most flammables are also excellent solvents for oil.
404Power I think you can do away with the solenoid valve coming out of the 1st phase separator, and check out the attached diagram for an even better trick for accelerating the initial cool-down.
Diverting liquid from the 2nd phase separator for the first 10-15 minutes after a warm start-up should speed up the cooling of the entire cascade-evap circuit without putting too much oil downstream in the process.
Moc on your question about which compressor to use, Rotaries are usually best when size is an issue. As for other advantages I'm not certain since I have no actual hands-on experience with anything other than a conventional hermetic. Perhaps someone else can jump with their experiences. Cap tubes vs. TXV, I would stick with cap tubes, since most TXV's were really only intended for a single refrigerant, and probably would be difficult (but not impossible) to match up with an auto cascade system.
Very interesting post mytek !
You've confirm that I've supect about R14 / Ar.
Nice Schematics and very usefull information :).
Sub cooler is used to create a SLHX where there are "no" incindence of charge put @ Evap, you can also use the "cold return" in the succion to make better T :).
Welcome in XS and have fun !
Thanks Steven ;)Quote:
Originally Posted by s7e9h3n
Hi, nice to meet you mytekcontrols :toast:
At last we have someone with big knowledge about autocascades (so bad that cryo-tek isn`t with us now).
Thanks for your answer! :)Quote:
Originally Posted by mytekcontrols
One more question: What do you mean with the term "liquid diversion valve"? I'm sorry but I don't know any valves like this! :( Do you mean a normal solenoid valve @ this position, which is closed for the first 10-15mins and after that, I have to open it up?
TIA! :)
regards
Patrick aka 404
are there any good books you would recommend from which i can learn more about cascades.
I have some experience with autocascade and TXV, but it didn't work as I hoped, cappilairy is more efficient. Long ago, Redwolf posted some pictures of his autocascade on Teampuss, he also used a TXV and it worked rather well but I still think cappilairy is a lot easier, no hunting, no superheat screw adjustments everytime you change the charge etc.
On the issue of oil sep, they're pretty useless in most cases. The refrigerant speed is very low in the phase sep so oil can't nearly get "upstream" and the other (low pressure) gasses are bigger in amount and liquid so they will carry the oil very good.
@n00b: SC12 is too small for an autocascade if you ask me. I've tried building one with an electrolux MP14FB but suction pressures just went up too high (3barg wasn't uncommon).
404Power... yes the "liquid diversion valve" is simply a solenoid valve followed by a cap tube which is sized probably about twice the flow of the one feeding into the top of the 2nd cascade (no exact science on this one, experiment and see what works best). It would be "opened" during the first 10-15 minutes (nothing exact about this either... experiment). However be sure that the solenoid is rated for cryogenic temperatures, since you will be seeing close to -60C at this point (most conventional solenoid valves are not designed to go below -40C without leaking). Something like an ASCO LN2 valve, or a Sporlan XUJ would do the trick.
I also got your email on the subject of how to size cap tubes. Since I feel it is of interest to all, I will answer the question here...
Unfortunately I don't have a clear cut answer on this one. Back in my development days, the approach taken was to base cap tube flows for a new design on an existing working system. Take the percentage of CFM difference between the existing system, and the new design, and then apply this percentage of change to the flow rates of the existing system's cap tubes. Since I was never a part of the development process for the very first system created and perfected, I do not possess the knowledge and/or the calculations that were used to create it, and thus fine-tune its cap tube flows for a working system. I also don't have access at this time to the original design paperwork for any of the units that I helped develop, and it has been nearly 20 years since I was doing this. My brain no longer retains the information :with:
LukeXE thanks for the compliment, but I am also equally impressed by what you have been doing as well (checked out some of your projects). I also loved how you recycled the MAPP gas cylinders into phase separators (now that's a GREEN machine!!!).Quote:
Quoted from LukeXE... At last we have someone with big knowledge about autocascades (so bad that cryo-tek isn`t with us now).
I have a good feeling that cryo-tek will be back, and probably pretty soon (he better, before I give away all the goodies).
Hey mytekcontrols I also have a question :).
The AUX Condensers... are they made like heat exchangers? Or are they just an additional fanned condenser?
Thanks :)!
the aux condenser is like normal heat exchanger, so it`s just SLHX before phase separator.
Aux if you look are heat exchangers, they need to be to be a heat exchange between high and low sides.
Cheers guys :)!
What sorta size would a pipe-in-pipe SLHX be? For either an autocascade or just a standard cascade?
Personally I think the most economical from my own stand point is 3/8 in 1/2, of course you could do better and there are commercial ones. I think Ricky's five or six 1/8 in 1/2 or the like is great too, but a pain with all the little endings. All up to you. 3/8" in 1/2" is very tight though, tight enough to use 1/2" for a coupling sometimes (i do)
Really just need ot find a fitting combo without too much room inside the center pipe. 1/4" in 1/2" may leave to much room in the outside though.
What about in terms of total length?
Could a plate HX also be used?
I think that plate HX for aux condenser will be too big, no need for that efficent heat exchanger. For sure about 1,5 long HX (6mm in 12mm pipe) will be enough (IMHO).
@mytekcontrols, I just want to ask about R22/R290. I used both in normal autocascade, with CO2 or R23, and ALWAYS I got much better results with R290/R600 instead of R22. Why ? R22 should be better, but it`s not (in my case)
Thanks again for your reply! :)Quote:
Originally Posted by mytekcontrols
My problem is now that I don't have any source for "special" solenoid valves! :( So may I have to go for the first solution @ the first phase sep! 2nd problem @ your solution for me is, that it's a lil bit difficult to get 2 captubes inside the really small evap! ;) Of course it's no problem to do this @ "real" auto-c's with a big evap! But our evaps are really small (as you know we use it for CPUs ... and they ARE small! :D) ... We'll see! :)
@ captube lengths:
Sounds quite interessting! :) But ... may you have any parameters based on your experience for such a 3-stage auto-c? Would be great! ;) :)
I just would need roughly estimated lenghts ... after that, we will see and go for a shorter/longer captube @ each stage!
regards
-404
btw:Agree with that! ;) :)Quote:
Originally Posted by LukeXE
the flow through a cap tube is dependent on the length, the ID and the pressure difference across it (and the refrigerant). Since you can estimate what load is applied to all the heat exchangers and you kind off now the compression ratio you can quess the cap length within a nice margin of error. Use the cap tube sizing rule that Gary Lloyd posted here few years back as an extra help. Cap tube sizing doesn't have to be rocket science, as long as the length is in the ball park your ok.
@ Unknown_road:
I know what you mean! ;) :)
Anyway, I would be really thankful for any help from you, mytekcontrols and/or any other user here @ XS! :) Would be great! ;)
regards
-404
I really hope you're right, but I'm not sure how he'll find the time. He's trying to fill an order currently -> 16 x 10Hp autocascades "probably" can't be hammered out overnight...can they? :p:Quote:
Originally Posted by mytekcontrols
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.Quote:
Originally Posted by 404Power
If I understand the question right, my guess would be that you are getting superior oil return with the R290/R600 combination. If you look at the boiling points listed below, R22 and R290 are virtually the same. So like you mentioned there really shouldn't be a big difference in this regard. However due to the fact that R290 is probably far superior to R22 at returning oil, it doesn't surprise me that it would yield better performance (remember any oil left inside the heat exchangers, will tend to inhibit the heat exchange process, due to an insulating affect). R123 also has good oil returning properties, so when combined with R22, will probably produce similar results.Quote:
Quoted from LukeXE... I just want to ask about R22/R290. I used both in normal autocascade, with CO2 or R23, and ALWAYS I got much better results with R290/R600 instead of R22. Why ? R22 should be better, but it`s not (in my case)
R22 boils at -41F
R290 (propane) boils at -44F
R600 (butane) boils at +31F
R123 boils at +82F
(sorry that the temps are not in degrees C, not on the chart I am using)