Captain....she really is beautiful!!! :DQuote:
Isnt she beutiful.
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Captain....she really is beautiful!!! :DQuote:
Isnt she beutiful.
That thing will trip breakers if its all on the came circuit. I have to run extension cords across the house to get enough power into one room.
Takes a fork lift to move too, nice.
Mine fits in a 24x24 inch square area and its on wheels.
Truly a thing of beauty, captain. Nice torchwork, too. Ya done good. :D
its on wheels i just have it up so i can work on it easier. And as fer the power i wired in a couple buck boosts so i get a little more bang for my buck on voltage. she is big though. If i wanted to spend money and buy new stuff i supose i could make her alot smaller, but thats what i got so thats what i get.Quote:
Originally posted by FUGGER
That thing will trip breakers if its all on the came circuit. I have to run extension cords across the house to get enough power into one room.
Takes a fork lift to move too, nice.
Mine fits in a 24x24 inch square area and its on wheels.
thanks gary:) :) :)
What are you using the Buck/Boost trans for? From what voltage to what?
damm bud nice work....
sorry i missed your phone call yesterday.
you called my home....i was at work....next time remember call work..i am there most of the time anymore...LOL
later,and again...great work:toast:
Damn.... how do you remember which tube goes where?
Excellent work man!
hello,
+ My first question, is that I'm just wondering about the power of the two compressors :
- first stage
- second stage
+ And what about cap, how did you calculate the lenght ?
bowman was saying that you were lucky about that because generaly you have to try some different lenght. But it could exist a way to calculate it, couln't it ?
really impressive ;)
the buck boost is just a single phase general purpose transformer, it basicly .....adds voltage to system kinda..
as fer the cap tube...i just kinda knew;) ;)
aenigma has been helping me out with the system design and cap tube size, as of late.
Is it a 12/24 or a 16/32? I take it you are raising 208 to either 220 or if it is a 16/32 somewhere near 230v.
12/24 120v trust me, it needs it,. i may ad a conditioning board to monitor voltage conditions.:) :)
heres a dupont link to properties, aplications, pressures, and everything else on most new refrigerants....507,410a,404a, ect...
http://www.dupont.com/suva/emea/products/index.html
alright these stickys are a little excessive. you can unsticky mine if you want.
its come to my atention that many of you would like to build cascade systems. Aenigma and myself made a short list that hopefully answers some simple questions for the "newbs". please let me know if i forgot anything.
Rules of a cascade system.
1. you need 2 or more compressors
2. if not 2 compressors than at least 2 stages, if you dont know what i mean by stage, dont even think of building one
3. You cannot just mix 2 refrigerants to get to colder teperatures.
4. i am quit sure, between all of the teachers at my local refrigeration technical school, they could not build a autocascade.
5. You cannot just chill water as a first stage unless its -35c water.
6. the high stage uses high temperature gas that condenses to liquid at -35c. if you cant do that, you cant have a second stage
7. if you havent built a working normal refrigeration system with minimal problems, dont try cascade.
8. Always build and test the 1st stage before touching 2nd stage.
9. High pressure switches ar always a good idea. set to 300psi.
10. if you meet the qualifications/rules, then relief tanks are absolutely mandatory.
11. NEVER use high pressure gasses you arent 100% sure about.
12 Always research the refrigerant you think you can use, check its vapor pressure diagram and properties and make sure it is compatible with everything in your system (copper, steel etc.)
http://www.airliquide.com/en/busines.../gases/gasdata is a great place to research your refrigerant.Coolpack/refrigeration utilites (http://www.et.dtu.dk/Coolpack/UK/" is a great utility for researching your refrigerant.
captaincascade... you once said you couldnt do a autocascade (it didnt work properly) and you had 450+ psi head pressures. Did you find the cause of this problem or did you just waved your hand and said "go to hell" ?
i was depressed so i had my aprentice dismantle it. i will try again soon.
im asking you about this cascade beacause of technical problems with my full cascade - compressors...
max i can afford is 1 compressor so im stuck with a autocascade wich i find easy to do and calibrate, i havent decided on what expansion valve ill use on the HX, im thinking of using a injector, the same thing on the cpu's evaporator. The second best would be a TXV with a 00X orifice... + the system i designed would be very small, almost prommy like.... And i could pretest my system on my trusted SC10B and later exchange the compressor for a bigger unit, like a SC18 wich is quite affordable
Assuming you dont join up your lowside HX on an auto, whats to stop you loading the lowside with hot water and a water pump with the expected heatload to get the high side charge right.
Then add an expansion tank and connect up the evap to the lowside (instead of pumping hot water thru the HX) and vapor charging with the lowstage refrigerant.
Surely that would get your charges right, although you dont really want to run water thru the lowside HX it was the first heat transfer fluid I could think of!
I still dont see an autocascade being overly difficult, although I usually overlook a thing or 50 ;)
]JR[
arro
good luck with that berkut. You may not find this as easy as your cascade was
gant
Its not that i want - i have to :\ And the harder the beter... thats why i also make a Jet engine atm, made a part of the combustor assembly and tested it with mapp gas and torches ;]
Ill post some drawings in a sec...
Quote:
Originally posted by ]JR[
Assuming you dont join up your lowside HX on an auto, whats to stop you loading the lowside with hot water and a water pump with the expected heatload to get the high side charge right.
Then add an expansion tank and connect up the evap to the lowside (instead of pumping hot water thru the HX) and vapor charging with the lowstage refrigerant.
Surely that would get your charges right, although you dont really want to run water thru the lowside HX it was the first heat transfer fluid I could think of!
I still dont see an autocascade being overly difficult, although I usually overlook a thing or 50 ;)
]JR[
yeah, i knew anegma would mention the water thing, and he did. We both asumed you would mention it to:D :D .
the reason i say that, and in fact the reason i posted this, was because of all of the strange question and statements that all the beginers keep saying about cascades... like: I plan to use argon and 404a , and expect to see -130c. just an example. so lets keep water out of the picture as far as this goes for now.
its a little different... the only gases i can afford are R22 and R23 beacause both are cheap.
I expect it to work, thats all...
Ok, first the pic...
Nah the water point is just to get the charge right in the system, not a coolant for the condensor or anything. If I were to go for it. edit: to make the system into a single stage first, thus not trying to balance a multivariable equation.
I would likely use R290/C02 to start since ive got both of them, and maybe some ethylene if I can aquire some from work.
My biggest problem though is compressors since the only ones i can get are pifflingly small fridge efforts atm...
]JR[
What is everything for in the system... basicly i dont have to explain anything to you guys exept why is everything placed like that...
1. the filter is placed there so it filters R22 and R23 vapour, and its uninterrupted by anything. When placed after the condenser "bubles" of r23 would blow through R22 liquid interrupting the flow...
2. the soleneoid placed on the R23 line is there to seperate the R23 part of the heat exchanger (with the injector on the evaporator), this way i can seperate the R22 part of the system so its possible to charge the system according to SCT and SST and Garys magical values like a normal chiller.
I think i dont have to say that R22 is subcooled by the R22 returning from the HX and R23 is being subcooled in the suction line from the cpu evaporator.
Im thinking of making a kind of venturi system to increase the vacuum in the cpu evap (very slightly but there will be some effect) using the flow from the HX's R22 part...
First off, use 2 filters, one on each liquid line.
You dont "need" a solenoid on the 2nd stage discharge line, just charge the system with only r22 and test it thoroughly to make sure there are no leaks and to be sure it works well.But if you use one then you wont have any load on the interstage when adjusting superheat.It will help to test unloaded and loaded conditions(when open and feeding r22 into interstage), so it is favorable, though not mandatory.I would prefer leaving it open so I could test the system with the interstage being loaded by the r22 condensing in it.
Since it will use a txv you can do the real fine tuning once the 1st stage is working properly and you are ready for the 2nd stage.Txv's are very forgiving, and when it is charged correctly you wont run the risk of starving the evaporator like you would with capillary.My method would be to make sure the 1st stage is working perfectly then turn the system off and let it sit until it is at ambient and static charge the r23 to a low safe pressure(probably 80-125psi) and then start the system closely monitoring pressures so they dont get too high.If all goes well then you can monitor all your temperatures and start fine tuning.
Since youre using a txv then you dont need to subcool the liquid line unless you want to lower the temperature of the liquid entering the evaporator.But I see too many drawbacks to make it viable.The obvious drawbacks being more insulation and having to make a new tube in tube heat exchanger with very small returns.And it would increase superheat quite a bit depending on how efficient it is.I just dont think a suction/liquid heat exchanger is worth it on a txv system that is fed 100% liquid vs. capillary that feeds vapor/liquid and really benefits from subcooling.
<edit>
One more thing, why do you say you dont have enough compressors?It seems you have 3 of them, i'd say that is enough for a cascade system that only needs 2.You need to start small with a basic cascade system before trying autocascade.If I remember right you already tested your old cascade and it didnt work right with r22 on both stages.Now youre trying to go into a full blown r23 autocascade system, I would recomend against that.
Im extremelly happy for your input aenigma...
NotedQuote:
First off, use 2 filters, one on each liquid line.
I hope you understand my way of thinking:Quote:
You dont "need" a solenoid on the 2nd stage discharge line, just charge the system with only r22 and test it thoroughly to make sure there are no leaks and to be sure it works well.But if you use one then you wont have any load on the interstage when adjusting superheat.It will help to test unloaded and loaded conditions(when open and feeding r22 into interstage), so it is favorable, though not mandatory.I would prefer leaving it open so I could test the system with the interstage being loaded by the r22 condensing in it.
When the interstage is cutted off only the R22 part of the system works, cooling of the R23 stage to lets say -40C unloaded. Now, opening the soleneoid causes R22 (when theres no R23) to rush in a -40C area filling that part of system completelly (when the injector on the evap is closed), so theres a crazy heat load for a moment, no condensing in the condenser, just the hx, the hx fills up (acting as the cool side of a heatpipe) and nada, no heat load, just more R22 in the system.
If the injector on the evap is open i see a different problem. Beacause theres such a cold space R22 stops condensing in the condenser, now it has a colder space to do that. The system starts cycling, HX filled up, heats up, condenser starts to work, feeds R22 to the TXV, HX cools down, theres a much colder space in the system (thx hx), no freon to the txv, hx fills up and again, and again...
I cant see it acting as a subchiller, the TXV has a too high throughtput, the HX is to efficient, i dont thing it will work that way.
Thats what i planned... But i dont thing that the R23 static pressure will be that low...Quote:
Since it will use a txv you can do the real fine tuning once the 1st stage is working properly and you are ready for the 2nd stage.Txv's are very forgiving, and when it is charged correctly you wont run the risk of starving the evaporator like you would with capillary.My method would be to make sure the 1st stage is working perfectly then turn the system off and let it sit until it is at ambient and static charge the r23 to a low safe pressure(probably 80-125psi) and then start the system closely monitoring pressures so they dont get too high.If all goes well then you can monitor all your temperatures and start fine tuning.
NotedQuote:
Since youre using a txv then you dont need to subcool the liquid line unless you want to lower the temperature of the liquid entering the evaporator.But I see too many drawbacks to make it viable.The obvious drawbacks being more insulation and having to make a new tube in tube heat exchanger with very small returns.And it would increase superheat quite a bit depending on how efficient it is.I just dont think a suction/liquid heat exchanger is worth it on a txv system that is fed 100% liquid vs. capillary that feeds vapor/liquid and really benefits from subcooling.
The oil in those compressors is incompatabile with R23 (needs poe) and i need to change the oil. The problem is the fact that i can get only ~30-50ml out in the begening. When i added 300ml of mineral oil to one of the compressors - not even a drop came out. Any good ideas ? IF theres a nice way to get rid of all the oil in these compressors and change it nice and clean - full blown cascade here i come.Quote:
One more thing, why do you say you dont have enough compressors?It seems you have 3 of them, i'd say that is enough for a cascade system that only needs 2.
the latest news would be: "works fine, now i need to change the oil in the II stage compressor so its R23 commpatabile". Calibrating a system with injectors is dead easy, fill it up so the injector doesent starve and change the frequency / pulse lenghtsQuote:
You need to start small with a basic cascade system before trying autocascade.If I remember right you already tested your old cascade and it didnt work right with r22 on both stages.
I also dont like that idea, unless a miracle happends ill probably be left with no alternative...Quote:
Now youre trying to go into a full blown r23 autocascade system, I would recomend against that.
Maybe you wondered why i am so stubborn- i like doing such things, the harder the better... I have few other projects being completed exept this one, like finishing a gas turbine wich will be a jet engine in its first form, later im going to convert it to a turboshaft engine and power a diy gokart...
Quote:
Originally posted by berkut
Maybe you wondered why i am so stubborn-
i was going to say more like 1 big autocascade ?
Yeah I know how it is wanting it to the complicated way. :)
I think you misunderstood me.I was just pointing out that a 2nd stage discharge solenoid is not mandatory, but it is a nice thing to have.If it closed then your system will act as normal with no load.Open it and vapor r22 will feed into the 2nd stage heat exchanger condensing and boiling off refrigerant from the 1st stage heat exchanger.So basically it will work exactly like an autocascade should, only with r22.But it is a great way to test your 1st stage for load handling capability.Never underestimate the heatload of latent heat of condensation.Just remember when testing like this you may have to add extra r22 depending on how much your 2nd stage injector flows.You dont want to starve the txv just because the 2nd stage is working.Once youre done testing it that way you can recover the extra refrigerant and get ready to use the r23.Quote:
I hope you understand my way of thinking:
When the interstage is cutted off only the R22 part of the system works, cooling of the R23 stage to lets say -40C unloaded. Now, opening the soleneoid causes R22 (when theres no R23) to rush in a -40C area filling that part of system completelly (when the injector on the evap is closed), so theres a crazy heat load for a moment, no condensing in the condenser, just the hx, the hx fills up (acting as the cool side of a heatpipe) and nada, no heat load, just more R22 in the system....
Well lets hope it is, because that is already 100psi over the pressure of the system(up to 250psi).Just make sure to use a large relief tank and you should be just fine.Although using an injector that works best with a full liquid line means alot more r23.Quote:
Thats what i planned... But i dont thing that the R23 static pressure will be that low...
Well you could always try it with mineral oil and see how it works, I think the main reason for using poe is for oil return, you could add some propane and see how that works.Another option would be switching the compressors, use the danfoss for 2nd stage and the a/c compressor for 1st.Quote:
The oil in those compressors is incompatabile with R23 (needs poe) and i need to change the oil. The problem is the fact that i can get only ~30-50ml out in the begening. When i added 300ml of mineral oil to one of the compressors - not even a drop came out. Any good ideas ? IF theres a nice way to get rid of all the oil in these compressors and change it nice and clean - full blown cascade here i come.
Why havent you posted results?I would be interested in seeing a full set of temperatures and pressures for a 2 stage cascade with r22 in both stages.Brings back memories of mine.Quote:
the latest news would be: "works fine, now i need to change the oil in the II stage compressor so its R23 commpatabile". Calibrating a system with injectors is dead easy, fill it up so the injector doesent starve and change the frequency / pulse lenghts
I have no deal... if i offended you in anyway.... didnt know it and it wasnt intended... im sorry for whatever i did.. guess its not my place here... cuQuote:
i was going to say more like 1 big excuse. i admited my autocascade didnt work right. whats yer deal?
berkut,
You did nothing that you need apologise for. Either the Captain misunderstood your post, or he fell out of bed that morning?
He's a good guy. He will realize it soon. He always does. It's so easy to be misunderstood on these forums. :D
dudes right, i was just being an ass (aparently its a little hobby i have goin). Consider yourself lucky, im stuck with me 24 hours a day, you can just walk away. heh, anyway didnt mean it as harsh as it sounded, sorry man.
:D :thumbsup:
Im back ;]
Sorry i was kind off strange, my fault, hard days.
Anyway back to buisness
The results look like this (i remember only the II stage)Quote:
Why havent you posted results?I would be interested in seeing a full set of temperatures and pressures for a 2 stage cascade with r22 in both stages.Brings back memories of mine.
-SSt - unreadeble on my cheapo gauge, well below the -60C mark on it
-Evap temp - unreadeble on my cheapo thermometer, well below -50C
-Injector- working perfectly, closing and opening like a charm, didnt leak even with these temps
-SCT - somewhere in the -25 to -30C's, bad vacuum and very low condenser capacities didnt make it easy
-HX's outlet temps unknown
Using R22... Thats why i didnt post any, lack of hardware with wich i can measure the temps and low side pressures.
The full cascade project is probably back on track beacause i managed to drill (rather mill with a mill bit and dremel) a nice hole in the top of my tecumesh and the oil drips nicelly. Did you know that it has a 3 or 3.5mm thick shell ?
The biggest problem while performing that operation was drilling the hole in such a way so no metal bits get in to the compressor. The dremel has a wonderfull thing in it- you feel the surface, how deep are u inside, and just before you completelly go through the shell theres a slight difference in the way it goes through, you have to feel it to know it. Anyway, the layer of metal wich was left had about 0.1mm and i punctured it with a needle, ill make a pic of it how it looks if you want to see it.
I bought a mig welder to weld a piece of 4mm steel with a service valve on that hole for later servicing, unfourtenetly no CO2 so i cant weld.
Oh, yeah there is no information at all.I find it odd your gauges dont read that low, time to invest in some real gauges.
On the drilling issue, I have used compressors that have been drilled to empty oil and scrapped and they work perfectly even with metal shavings.I think I would have just filled the compressor with oil and then turned it upside down and clamped it so when I drill through it the oil rushing through the hole would carry metal shavings with it.
I use an oxy/acetylene torch so I can weld the holes, but welded joints are probe to leaking because it leaves pinholes, but you can braze it.Silver solder works perfectly to seal holes in the shell.Yeah those shells are quite thick, I have one here with a big cut in the side from my cutting torch, really shows how thick it is.
ok heres a start on what we talked about. modorators please move or whatever if you want..... if you have more sugjestions for threads that are useful please pm me. i dont want to load this thing up with spam
this is just the start......first 3 pages
stuff from people that are building cascade systems
pc ice
http://www.xtremesystems.org/forums/...threadid=25057
piping and recomended oil per refrigerant.
http://www.xtremesystems.org/forums/...5&pagenumber=1
parts
seal string
http://www.xtremesystems.org/forums/...threadid=25010
questions on subcooling
http://www.xtremesystems.org/forums/...threadid=24918
thread on charging refrigerant
http://www.xtremesystems.org/forums/...threadid=24797
guide on insulating your pc
http://www.vr-zone.com/?i=230&s=1
thread on upgrading your mach 1 or 2 from 134 to 404a,507
http://www.xtremesystems.org/forums/...threadid=24796
die electric grease
http://www.xtremesystems.org/forums/...threadid=25041
insulating gpu
http://www.xtremesystems.org/forums/...threadid=22957
thread on basic refrigeration
http://www.xtremesystems.org/forums/...threadid=24471
thread on autocascades
http://www.xtremesystems.org/forums/...threadid=24035
heres a good one on compressors as vacuum pumps.
http://www.belljar.net/refrig.htm
this site has alot of good info on general refrigeration and troubleshooting
http://www.hvacwebtech.com/HVACTechNotes.htm
so captain crunch what r ya workin on now? And I havent heard what system you are running. With -130 temps you should get an Athlon 1.4 JIUHB and see how far you could push it with DDR 533. Just a thought.
yeah, i was thinking about buying some k6 2s or durons and seeing how far i could push them. just because they are cheap and i can destroy them.
BTW: I would be careful about throwing Captain Crunchs name around like that. He is a real person and although "retired" now, someone you don't want pissed at you.;)
would you guys rather see me build a big ugly autocascade, or some complete single stage systems?
I can't decide wich is more important right now.
help me be decisive, please.
lollerskates...Quote:
Originally posted by TheDude
BTW: I would be careful about throwing Captain Crunchs name around like that. He is a real person and although "retired" now, someone you don't want pissed at you.;)
and capn'
You should make a wicked autocascade. THEN TORTURE SOME OLD DURONS WHICH ARE EXPENDABLE!!!!
Towards the middle of next month I'd like to see you build a few single stage systems. ;)
Right now though... whatever you(or someone willing to put up a little $$$) want.
my dilema is i now have the ability to build an autocascade, but i really need to finish up some systems. The only reason im in a hurry is that i feel pressure to be the first to build 1.
And by the way, its to late i have begun the building of the autocascade. this will be purly to show that i can build one. So it wont be pretty or suitable for pc use.
hey capn, how much would a 134a GPU cooler set me back? Danke.
wait to see one you want.Quote:
Originally posted by Slickthellama
hey capn, how much would a 134a GPU cooler set me back? Danke.
OK autocascade built. Lets see what she does. im putting it on the vac pump right now. only problem with her is shes a 3 phase scroll. A little overkill but i just want to get this overwith.
you know you gotta post a pic of that beast!
Good luck CC, hope it works like a wonder!
its not working, how depressing. ill give it another go tomorrow.
Could you share your problems with us ? This could be really helpfull
I don't know if this has been posted here, but I saw it somewhere and wow it is REALLY helpful:
http://www.jwharris.com/jwref/procs/
heres the autocascade. didnt work great but hey it was autocascading. not bad for a 2nd try. -60c in a positive pressure on suction.
hey guys check it out. www.captaincascade.com
You cool the compressor with a additional cooling loop ? I see it wrapped with some hose
Wow. Nice logo, CC. :DQuote:
here is my new toy. its much like charlies but alot bigger. and designed to chill liquid to -140c. Its got a big ass 3 phase bitzer in it:D. wich is something ive always wanted. Much like charlies it is empty of gas, and on the tag for refrigerant type it says "polycold".
Its fine by me, i didnt really plan on using it the way it is. i just wanted to gaze at its inards, and maybe steal that beutiful bitzer. 10$ on ebay. score!
$10? Damn! I bet shipping was a :banana::banana::banana::banana::banana:. Can you handle 3 phase power?
:toast:
it was local:D yeah i have 3 phase at the shop:D:D
cool! :thumbsup:
Nice system dude CC :)
Well, fit a nice evap to it and go for -150 ;)
autocascade completed. will have pics tomorrow. not working as well as i would like it to, but hey it works. ill start a thread about it since nobody looks at my poor old thread anymore.
Yep mine is completed too, and it isnt working as well as I would like either, but it is only a little 1/3hp copeland.So I cant expect too much.Also not real sure about the efficiency of the nitrous oxide.
They are interesting little beasts.
he did finish before me. but doesnt mean that he isnt wearing a sundress like a cute little girl
hahaha
Okay mr. barbie helmet. :D
We still read your thread Cappy....this is just what you need to perk it up! :D
that was an isolated insedent!Quote:
Originally posted by aenigma
hahaha
Okay mr. barbie helmet. :D
ok heres the top view. i got to -75c with 1 compressor. and it was autocascadeing because suction was in a positive pressure
Taking it to Lan parties?:D
CC, how much does cooling the compressor help you (not evap temp - compressor)
I believe the only reason he was doing that is because the compressor was hot enough to boil water, so he was worried about it.Those high compression ratios are murder.
I dont think there would be much of an improvement when cooling the compressor unless it cooled it enough to considerably drop discharge temps and pressure.The only improvement would probably be more life from the compressor and no burning the oil.Which in my opinion is a good improvement. :)
But you definately do not want to cool it too much(enough to cool discharge line/oil sep below SCT of 1st stage refrigerant) or else you will condense the 1st stage refrigerant in the oil seperator.That is why the oil seps are insulated in autocascades.
I just thought i would share an idea with those of you building your own systems.
For an enclosure for your system, you'd want something sized like a prommy right?
how about a 19' craftsman tool box? or even a u.s. mail box?
cut off each and and toss some perferated metal on there for ventalation. and there you go.
ok, as you may or may not know. my three stage is not working properly. And i think i have gotten to the bottom of it. This was something very stupid of me not to antisapate. In making my own heat exchangers, i have not asured the where equal in size. What is happening is my 2nd to 3rd stage heat exchanger is much larger than my 1st to 2nd. so, my2nd stage is picking up alot more heat than it can reject to my first stage. it kills my first stage innerstage. and the 2nd and 3rd stage pressures rise astronomicly. this also aplies to autocascades. they dont have to be exact, but the heat exchangers should be close in size. when using a multi stage system.
lmao......hold on a sec...........hmmm
The 3d stage picks up the heat load (device cooling + heat through insulation) and then adds heat of compression (25-50%), so the 2:3 HX needs to be large enough to handle this. The 2d stage picks up that heat load, adds more insulation heat load plus more heat of compression, so the 1:2 HX needs to be larger than the 2:3 HX in order to handle the increased load.
I'm not sure this is true for autocascades. It seems to me that autocascade HX's need to be about equal size.
my three stage hurts
I feel its pain. :(
Maybe you need to swap the two heat exchangers, so that the 1:2 is larger than the 2:3.
1st stage is cap tube, im gunna throw a txv on there. we'll see what happens
Ive been working on tons of information. Its not done yet, but its still a very useful resourse right now.
come check out my forum
http://www.captaincascade.com/forums/index.php?act=idx
I forgot to mention my forum is having a contest to see who can submit the most useful refrigration information.
the winner gets 2 1hp copeland low-temp cascade compressors!
just wanted to let you guys know, im not dead. And i am still working right along.
Heres a new one im almost done with.http://www.captaincascade.com/forums...1078263799.jpg
I have decided, that for every 200Btu/h of rated capacity (THR - including motor cooling and superheat) that 1' per 200btuh of (2 pieces) of 3/8" copper soldered together (side by side in a helix) should handle an interstage load at about a 110deg TD .... derived from what I did. ;)Quote:
Originally posted by captaincascade
ok, as you may or may not know. my three stage is not working properly. And i think i have gotten to the bottom of it. This was something very stupid of me not to antisapate. In making my own heat exchangers, i have not asured the where equal in size. What is happening is my 2nd to 3rd stage heat exchanger is much larger than my 1st to 2nd. so, my2nd stage is picking up alot more heat than it can reject to my first stage. it kills my first stage innerstage. and the 2nd and 3rd stage pressures rise astronomicly. this also aplies to autocascades. they dont have to be exact, but the heat exchangers should be close in size. when using a multi stage system.
lmao......hold on a sec...........hmmm
PS - the first stage load will be higher than the second stage load, and the second stage load will be higher than the third stage load. I think you would use a multiplier of about 1.25 to 1.35 to calculate the THR. The multiplier decreases as the evaporating temperature increases. Probably 1.5x for the third stage!
Cheers!
Take your lowest stage evap heat load (plus a little for insulation gain). Add heat of compression (25% or so). That is the heat load for its condenser, which is the heat load for the next stage's evaporator. Add heat of compression to determine that stage's condenser load, which is the evap load for the next stage up. Etc., etc., etc...
If I could figure out what you said, I would be happy to translate. :DQuote:
I have decided, that for every 200Btu/h of rated capacity (THR - including motor cooling and superheat) that 1' per 200btuh of (2 pieces) of 3/8" copper soldered together (side by side in a helix) should handle an interstage load at about a 110deg TD .... derived from what I did.
for every 200Btu/H of required THR in an interstage, 1' of copper (length) is required for the interstage heat exchanger (at 110degF TD)...
Is that better? :D:
PS... nice sig, Gary... :p:
Yep, it's pretty cool. You do nice work, Mark. Thanks. :DQuote:
PS... nice sig, Gary...
Okay, let's see if we can figure this out.Quote:
for every 200Btu/H of required THR in an interstage, 1' of copper (length) is required for the interstage heat exchanger (at 110degF TD)...
If we have an evap heat load of say 400btu, add 25% for heat of compression, for a total of 500btu, then we need about 2.5 feet of 3/8OD copper tubing for one side of the heat exchanger. Does that sound about right?
What do you mean by TD? Surely you can't be suggesting 110F difference between the two refrigerants?
Yes, that is what I was suggesting. If you wanted, say a 55deF TD, you would double the length. I propose that he relaitonship is proportional.Quote:
Originally posted by Gary Lloyd
What do you mean by TD? Surely you can't be suggesting 110F difference between the two refrigerants?
I was running a -10F suction temperature (not SST, but acutal) with an R-13 SCT of about.. OH! :eek: I take that back... the R-13 was at a saturation temperature of about 15degF... so about a 25degF TD...
Thanks, Gary...
Does that sound better?
Cheers!
That's much more like it. Now cut that in half (10-15F SCT/SST TD), and this is what we normally see in commercial systems.
Do you recall what the SST was?Quote:
I was running a -10F suction temperature (not SST, but acutal)
SST? of the first stage? or second stage? The 25degF TD was under a good load with my 160W water condensate heater, that I actrually think is more like 300watts, if you consider the total suface area of the pan, plus the heat output of the heater.
:D
In any case, I think any rule of thumb coming from this would only apply to tubes soldered in helix. Other types of heat exchangers would have different rates of heat exchange, contact surface area, wall thickness, etc.
Quote:
Originally posted by Gary Lloyd
In any case, I think any rule of thumb coming from this would only apply to tubes soldered in helix. Other types of heat exchangers would have different rates of heat exchange, contact surface area, wall thickness, etc.
Absolutely.. ;)
I am in full agreement....
Cheers!
man, im gone for five minutes.......you guys...
Time for Kommando to do alot of reading on cascade systems as he wants to try it some time next year :)
beware!
Theres a new creation lurking. I am calling her "captainCascades Revenge".
Tell you one thing, It aint energy efficient....:D:D:D:D
anxious to see THAT!!! :slobber:Quote:
Originally posted by captaincascade
beware!
Theres a new creation lurking. I am calling her "captainCascades Revenge".
Tell you one thing, It aint energy efficient....:D:D:D:D
C
Anyone got a pic of what the cascade thing cools the heat exchanger or something?
what?Quote:
Originally posted by kommando
Anyone got a pic of what the cascade thing cools the heat exchanger or something?
LMAO :rotf: :rotf:Quote:
Originally posted by captaincascade
what?
Imagines captaincascade reading that sentance and being just plain puzzled.
I really just dont understand. I read the sentence like 4 times, thats pretty much the way it happened russel lol.
pics dont work