Single-stage auto-cascade build [Archive]

tiborrr

08-14-2009, 01:03 PM

So, it has finally begun. Phase separator was already build few months ago:
http://www.shrani.si/t/3w/BG/1OEqNboA/dscn1290.jpg (http://www.shrani.si/?3w/BG/1OEqNboA/dscn1290.jpg)

Today I coiled one of the two coaxial heat-exchangers and braze it to the phase sep:
http://www.shrani.si/t/3z/77/GELcwRl/dscn1306.jpg (http://www.shrani.si/?3z/77/GELcwRl/dscn1306.jpg)

Second (cascade) HX, waiting to be coiled :p::
http://www.shrani.si/t/3j/gI/1UvTFz6B/dscn1303.jpg (http://www.shrani.si/?3j/gI/1UvTFz6B/dscn1303.jpg)

Compressor for test run - Danfoss FR7.5, scrapped from a working freezer. Already grinded down some rust, now it just need some primer + coat love:
http://www.shrani.si/t/o/3r/3tP6HR3F/dscn1304.jpg (http://www.shrani.si/?o/3r/3tP6HR3F/dscn1304.jpg)

I'm going out for a beer or two now!
Best Regards,
N. :up:

-EC-UnRockStar

08-14-2009, 02:08 PM

i think the Compressor is to small to handle a load ~200W

Gases?

Subcooler?

tiborrr

08-15-2009, 07:39 AM

[XC] gomeler

08-15-2009, 12:22 PM

Best of luck with this, I hope it works :)

[486]

08-15-2009, 02:16 PM

You purge the lines so far? I gave up on my auto mostly because of that, the HX and phase sep has so much oxide in it...

Why not mix in a little propane for the high temp stage, it'll help cool off the co2 in the second. Or are you hoping to avoid dry ice by having a higher HX temp. It has been a while since I've been into this stuff, so sorry if my questions seem dumb...

captaincascade

08-16-2009, 12:32 AM

Hi,

Compressor is just for first run to test out everything. There are some rotaries standing by :) Subcooler is seen on the second picture, the gases will be n-butane R-600 & R-744.

Best Regards,
N.

If you have the compressor your planning to use, then use it. these things are finicky enough without tuning them to work, then changing a part and tuning again

tiborrr

08-16-2009, 07:42 AM

@Gomeler: Thank you, buddy. I try to keep my expectations low, but still I'm excited as the project is about to enter the 'charging phase' :up:

@[ 486 ]: Yeah, I purged the lines with nitrogen shielding gas. Used about 1/5 of the 10kg tank just for purging and pressure testing. I'll try to avoid R-290 in the charge as it will 'contaminate' the CO2 charge, making the final CPU evaporator temperatures warmer. I think Mytekcontrol's topic explains this the best (http://www.xtremesystems.org/forums/showthread.php?t=144007).

See, almost emptied my N2 tank :):
http://www.shrani.si/t/W/12c/2CqFvqrY/dscn1313.jpg (http://www.shrani.si/?W/12c/2CqFvqrY/dscn1313.jpg)

@captaincascade: I'll keep that in mind, sir! :yepp:

Here is the final auto-cascade HX assembly with SLHX (refered as 'auxillary' HX by Mytekcontrols), main cascade HX and a liquid/gas phase separator. Had a few leaks at the T-joints, repaired them quickly and now the assembly appears to be leak-proof (still under nitrogen charge):

http://www.shrani.si/t/44/XT/2h2TsQes/dscn1309.jpg (http://www.shrani.si/?44/XT/2h2TsQes/dscn1309.jpg) http://www.shrani.si/t/3V/c8/5S5KY8/dscn1310.jpg (http://www.shrani.si/?3V/c8/5S5KY8/dscn1310.jpg) http://www.shrani.si/t/u/y9/4zcpbxZ/dscn1311.jpg (http://www.shrani.si/?u/y9/4zcpbxZ/dscn1311.jpg) http://www.shrani.si/t/3p/P2/1yPay0fs/dscn1312.jpg (http://www.shrani.si/?3p/P2/1yPay0fs/dscn1312.jpg) http://www.shrani.si/t/5/CZ/3bobSQtc/dscn1314.jpg (http://www.shrani.si/?5/CZ/3bobSQtc/dscn1314.jpg)

The long horizontal lines are compressor discharge (condenser) and compressor suction. The port, which is at the moment brazed shut, coming from phase separator's gaseous line is for the direct bypass (of gaseous refrigerant directly to expansion tank).

Best Regards,
Niko :up:

[486]

08-16-2009, 12:55 PM

@[ 486 ]: Yeah, I purged the lines with nitrogen shielding gas. Used about 1/5 of the 10kg tank just for purging and pressure testing. I'll try to avoid R-290 in the charge as it will 'contaminate' the CO2 charge, making the final CPU evaporator temperatures warmer. I think Mytekcontrol's topic explains this the best (http://www.xtremesystems.org/forums/showthread.php?t=144007).

I mean R290 in the first stage rather than the butane. Or is it that dry ice problems can be avoided if you keep the co2 closer to it's critical temperature, dropping it in temperature just enough to allow it to condense with reasonable pressures.

If your nitrogen tank runs empty, I always use propane, there isn't enough air in the lines at any time for it to ignite, so it is pretty safe, so long as you are outside. It also gives a nice visual indicator of how fast the purge gas is going through the tube, I keep the flame at the outlet end around 3" tall, good amount of gas going through, but not so much as to waste it.

tiborrr

08-16-2009, 01:02 PM

R-600 is probably more suitable than R-290 because butane will absorb more CO2 in the newly formed solution. Can't explain it properly since English isn't my native language, but this is the post that will probably explain this a tad better - link! (http://www.xtremesystems.org/forums/showpost.php?p=2185946&postcount=8).

I tend to avoid purging with propane, I can recharge the Nitrogen tank for less amount of money than buying a 5kg propane tank. But thanks for your input, [ 486 ]! :up:

[486]

08-16-2009, 04:10 PM

R-600 is probably more suitable than R-290 because butane will absorb more CO2 in the newly formed solution. Can't explain it properly since English isn't my native language, but this is the post that will probably explain this a tad better - link! (http://www.xtremesystems.org/forums/showpost.php?p=2185946&postcount=8).

Oops! I forgot you were talking about an autocascade, I was trying to figure out why the refrigerants would be mixed in a 2 stage cascade! Sorry for any confusion I caused!

tiborrr

08-17-2009, 02:51 AM

No harm done, [486]! :up:

Just ordered a single-row 0.72kW condenser with 230mm fan /w 10W Papst motor. Hope it will do well with 9400BTU/h L'Unite Hermetique R-22 rotary I will use (I am skipping the Danfoss FR7.5 as per captaincascade's advice). Rotary uses AB oil, R-600 is compatible with mineral and AB so no issues there I think.

:cheer2:

tiborrr

08-18-2009, 08:05 AM

Pipeline finished, but I ran out of both fuel & oxygen for my brazing torch. Will have to wait until Thursday but in the meanwhile I will manufacture the base plate, the HX housing and bolt down all the components.

http://www.shrani.si/f/x/12q/26M2rJLr/dscn1315.jpg

http://www.shrani.si/f/14/11a/4vk9cObd/dscn1316.jpg

Best Regards,
N. :up:

Turrican

08-18-2009, 08:08 AM

wow, looks awesome bro
would be great if mine could be tuned a bit if possible. :D

Patrickclouds

08-18-2009, 09:14 AM

hast this flex pipe pvc in it?
or is this only stainless steel?

tiborrr

08-18-2009, 11:49 AM

Ofcourse stainless steel, I have never used PVC tubing before.

tiborrr

08-22-2009, 03:22 PM

Auto-cascade assembled, currently pressure tested. Tommorow - if no leaks are to be found - I will vacuum the system using the standard triple-vacuum method and charge it with R-600/R-744 for the first time. I may need to charge a bit of R-507 to blend with the CO2 and help flushing dry ice.

http://www.shrani.si/f/q/3V/1d4oqpaQ/dsc1031.jpg

Brazed shut port is the so-called wdrzal safety expansion port :lol: It will be used for HPCO.
http://www.shrani.si/f/1F/ph/2HDWjs0g/dsc1032.jpg

http://www.shrani.si/f/g/Cz/16radtEm/dsc1033.jpg

Gas (CO2) line bypass with ball valve connected to expansion device:
http://www.shrani.si/f/1F/as/4T8MZnNA/dsc1034.jpg

tiborrr

08-23-2009, 04:21 AM

Update: The rest of the piping appears to be leak-free during the night, will leave it another day just to be sure! :up:

Turrican

08-23-2009, 12:13 PM

wow, looks very nice.:up:

trust me guys, i've seen it myself live.:D

SAE

08-24-2009, 09:48 AM

Wow, eager to see how it performs. :up:

K404

08-24-2009, 03:44 PM

IM an outsider to phase change but its good to see an autoc again :D

Hope it goes right first time tiborr :D

ruffus

08-24-2009, 05:48 PM

looks real nice man can't wait to see how it works out as i got my self a real big scroll compressor to make mine from when or if i ever get that far as i still have to get this cascade out that i have been building for the last 9 months

tiborrr

08-25-2009, 12:55 PM

Thanks, guys! :up:

First charging went well, although I already ran out of butane. Damn can, two charges and it's over... I'll get re-stashed on thursday, but in the meanwhile I'll insulate the whole auto-cascade, especially the HX stack. I think I can get another 10-15°C just by adding insulation.

http://www.shrani.si/f/D/RP/2OCGwdLa/dsc1035.jpg

First charge - too much of R-600:
http://www.shrani.si/f/12/sY/2NX4toCr/dsc1041.jpg

Uninsulated auto-c @ R-600/shot of R-507/R-744:
http://www.shrani.si/f/p/sT/3BkTTaNJ/dsc1047.jpg

Best Regards,
Niko

quintus

08-25-2009, 01:03 PM

Hell yeah! you go men;)

bartx

08-25-2009, 01:05 PM

Nice bulid. Looks very neat :up:

[XC] gomeler

08-25-2009, 01:47 PM

Very nice start. Can't read the gauges too well when blowing up the image, what pressures are you running? Looks like 2 bar suction and 11 bar discharge?

bartx

08-25-2009, 01:54 PM

I think that's 0,5 bar suction and 11 discharge :)

[XC] gomeler

08-25-2009, 02:09 PM

Right you are, I just saw the 5 atm per tick scale on the high-side and applied it to the low-side without thinking. Need my gauges to read in PSI :p:

tiborrr

08-25-2009, 04:05 PM

Thanks guys. I ran out of R-600 at the moment so the charge at the moment is consisting mainly of R-507 & R-744 with what ever I could scrap out of the butane bottle. Pressures are 1.2barg & 15barg, uninsulated. One more proof of how good of a high boiler butane is. I noticed a drop of 1bar on high side just by putting a cardboard in front of the HX stack (so the condenser fan doesn't blow air directly over it) for 10-15 seconds. I think insulation will help a lot.

Too bad I shoot the first two charges like it's no tommorrow :shrug: :D And oh, Gomeler - the pressure readings on the gauges are PSI aswell - the closest to the circle center, black labeling.

Best Regards,
Niko :up:

tiborrr

08-26-2009, 04:44 PM

Pour-foamed HX stack, take two. Will need another can to fill everything up and then cut away anything wider than the base board.

http://www.shrani.si/f/2w/WR/4fX8Mh8h/1/dsc1049.jpg

SAE

08-26-2009, 05:01 PM

Looks like there was an ugly huge insect that built its homely nest in there, lol :lol:

EliTE22

08-26-2009, 10:18 PM

nice, clean build :clap:
but why not use cardboard or wood as a mold for the foam? just wondering would have been nice and square:D

hope it performs great btw

Postal Dude

08-27-2009, 04:58 AM

Hey Niko.

Im considering doing something along these lines, straying from the usual AC to SS conversion. I got slightly deterred by reading that auto-c's are a pain to tune and more importantly, have trouble holding high loads.

What load are you expecting this to hold?

Can you post the gas mix you are using once you have it all sorted. Cheers

tiborrr

08-27-2009, 10:25 AM

Thank you guys! Don't know yet what load will it handle, but I think 200W shouldn't cause no trouble. I'm still in the 'optimal charging' phase, haven't hooked up my computer yet.

Here's a fresh charge of R-600/R-507/R-744. At the moment I have great issues with dry ice forming, but will a little patience I think I can get it to -75°C.

http://www.shrani.si/f/1D/7O/3fgtNju0/dsc1050.jpg

http://www.shrani.si/f/1G/BA/3JZa5B72/dsc1058.jpg

Best Regards,
N. :up:

-EC-UnRockStar

08-27-2009, 11:28 AM

R507 Doesn´t work in a Auto-cascade

use R290 or R134a

Ozzfest05

08-27-2009, 01:52 PM

Tiborr you know way more then me and are far more experienced in building these units, but, If you can get it R22 is a mixture of R600 and R290 instead of what your using it would make tunning it a hell of a lot easier, take out that 507, R22 and C02 mix I think would give you less headache and better results. I have had good luck with r22. Good Work!

tiborrr

08-27-2009, 03:55 PM

@UnRockStar: R-507 is azeotrope, that's why I decided to take it. Plus it doesn't carry AB oil (neiter does CO2) so the evaporator cannot get clogged. I used it only as a dry ice solvent / flusher. You think it might be better to try with R-290? :up:

I've tried new charge with less R-600 and more R-507 instead. The results are as followed:
http://www.shrani.si/f/29/3f/4aUdnzVV/dsc1077.jpg

Low side -0.1barg (5" Hg) in slight vacuum, High side 6barg (90psi).

http://www.shrani.si/f/1f/12j/4XlJAynt/dsc1066.jpg

Gaseous line leading from the phase separator:
http://www.shrani.si/f/1O/Ag/t6EbMen/dsc1071.jpg

@Ozzfest05: Thanks buddy, but I would like to correct you. R-22 is not R-290 + R-600 mix. It's a HCFC refrigerant. What you are talking about is a classic cooking gas (~ 70% propane / ~ 30% isobutane). Will try that tommorrow, just have to manufacture the the appropriate left-turn flare with SAE G1/4 hose adapter.

Best Regards guys,
Niko

tiborrr

08-28-2009, 06:05 AM

Just made myself an adapter to charge propane or propane/butane blend (cooking gas) so I can experiment even more. As per advices I will dump the R-507 and rather stick to R-290/R-600 blend:

http://www.shrani.si/f/2B/GP/JPccfUj/dsc1078.jpg

Perhaps I can reach -80°C soon enough :P

sdumper

08-28-2009, 08:49 AM

Very nice job!!!!!

teyber

08-28-2009, 09:22 AM

you can get it! your close! :D

[XC] gomeler

08-28-2009, 03:34 PM

Now we need to see how this system handles a load :p: Know when you'll load it up? Any chance of acquiring R170 to charge with?

quintus

08-28-2009, 03:56 PM

gomeler;3984267']Now we need to see how this system handles a load :p: Know when you'll load it up? Any chance of acquiring R170 to charge with?

I would go for r23 as r170 likes oil too much.

tiborrr

08-28-2009, 04:53 PM

Hi fellas! No load until sunday I think. Gotta get pour-foamed the rest of the stack. I made a brand new charge today, -72.5°C with solid 0.1bar LP / 8bar HP, avoided the R-507 as I only charged R-290/R-600 cooking gas blend and CO2. Eco friendly gas charge and it's very cheap too :D. The ambient temperature was well above 31°C :) It was a really hot day!

http://www.shrani.si/f/1H/4J/2DInfEC8/dsc1080.jpg

http://www.shrani.si/f/2m/IY/4S6dn9ET/dsc1081.jpg

http://www.shrani.si/f/2P/qu/3ctYcz72/dsc1082.jpg

Any chance of acquiring R170 to charge with?
Don't know, but do you think If I rather go a bit easier on the CO2 charge and add some R-1150? I think I could get into -85°C league with some positive back pressure, what are your thoughts on this charge?

Best Regards and thanks for your nice thoughts and enthusiasm,
Niko :up:

piotres

08-28-2009, 04:54 PM

I'm very interested how that will perform with load ...

Good luck :)

PS. You're right about insulation (which You wrote in mine topic about suction lines) ;-P

Peter

tiborrr

08-28-2009, 04:56 PM

Thank Pieter! Yeah, would sure need an helping hand with insulation :yepp:

Regards to Poland,
N. :up:

teyber

08-28-2009, 07:03 PM

lol it was 43c here in socal today :(

sdumper

08-29-2009, 08:22 AM

Tiborrr someday im going to need to have a talk with you on how you designed your phase separator because I have looked at it over and over and am still not able to trace all the pipes :) Very well done keep up the great work!!!!

tiborrr

08-30-2009, 12:38 PM

I think i'll need another 500mL can of polyurethane foam since there are still few gaps left to be filled :lol:

http://www.shrani.si/f/0/5e/e1QRRwX/1/dsc1086.jpg

http://www.shrani.si/f/1U/EM/2EWpVMKT/1/dsc1087.jpg

http://www.shrani.si/f/3c/4R/2GD06Y7w/1/dsc1088.jpg

Added a bit of R-290/R-600 and got -79°C at 1bar LP/7.2bar HP:
http://www.shrani.si/f/18/KE/42l7gxLU/dsc0005.jpg

Re-quoting myself:

Don't know, but do you think If I rather go a bit easier on the CO2 charge and add some R-1150? I think I could get into -85°C league with some positive back pressure, what are your thoughts on this charge?

@Pieter: Thanks bro, more about load holding abilities tommorrow! :up:
@Sdumper: No problems buddy, i'll draw schematics of it, just remember to remind me about doing that from time to time :D

Best Regards,
N.

teyber

08-30-2009, 10:11 PM

jesus christ mate!

this is so good, so compact and so clean!

tiborrr

09-03-2009, 07:07 AM

First tests are here, I have a bit too much of propane R-290 in the system, that's why I'm recharging it now. I reckon I can get another 5°C under load.

http://www.shrani.si/f/33/TV/3zkcreAc/dsc0033.jpg

http://www.shrani.si/f/a/Pb/4oybd6d2/dsc0034.jpg

Results:
125W = -56.2°C
160W = -53.6°C
190W = -52.8°C
210W = -52.1°C
225W = -50.7°C

T ambient = 29°C
Power consumption = 490-560W (idle/load)

Best Regards,
N. :up:

tiborrr

09-03-2009, 09:01 AM

Brand new (final) charge, same :banana::banana::banana::banana:ty me! :ROTF:

http://www.shrani.si/f/v/WO/4gjiSaHn/dsc0050.jpg

Not 5°C but 9°C better temperatures at same load! -60°C @ 225W load :cool: I charged less propane (which was contaminating the CO2 charge) and a tad more CO2.

New results:
125W = - 63.5 ~ -64°C
http://www.shrani.si/t/1p/Wh/3Dl08ywW/dsc0051.jpg (http://www.shrani.si/?1p/Wh/3Dl08ywW/dsc0051.jpg)
...
225W = -59.5 ~ -60°C
http://www.shrani.si/t/z/uN/4gCbUAkT/dsc0068.jpg (http://www.shrani.si/?z/uN/4gCbUAkT/dsc0068.jpg)

Tambient = 27°C

Pressure readings - 11.2bar HP (off / discalibrated by about 0.5bar) / 0.6bar LP & power consumption ~ 480W @ load
http://www.shrani.si/t/3N/2I/3LU6R3Hr/dsc0063.jpg (http://www.shrani.si/?3N/2I/3LU6R3Hr/dsc0063.jpg) http://www.shrani.si/t/3H/Cm/189vhU2d/dsc0060.jpg (http://www.shrani.si/?3H/Cm/189vhU2d/dsc0060.jpg) http://www.shrani.si/t/a/7f/3hAhVNGf/dsc0064.jpg (http://www.shrani.si/?a/7f/3hAhVNGf/dsc0064.jpg)

I think that's about the best I can get out of R-600/R-290/R-744 combo. Next stop - ethylene & hopefully 10°C better temperatures at load! :up:

Best Regards,
Niko

Dualist

09-03-2009, 09:16 AM

Bloody awesome work there mate :up:

I feel inspired to something similar :D

tiborrr

09-03-2009, 12:58 PM

Thank you, buddy! :up: I think I'm gonna try to see how it does with my HD4890 :)

SAE

09-03-2009, 01:07 PM

Don't forget to post results. :D :up:

[XC] gomeler

09-03-2009, 01:56 PM

Nicely done. Looking forward to seeing what you can manage with R1150. How long is the pulldown on this thing and do you have a way to combat the initial high-side pressure spike?

piotres

09-03-2009, 02:31 PM

Do You have dummyload ? :rolleyes:

teyber

09-03-2009, 02:43 PM

holy smokes complete success!!!

tiborrr

09-03-2009, 03:16 PM

gomeler;3993635']Nicely done. Looking forward to seeing what you can manage with R1150. How long is the pulldown on this thing and do you have a way to combat the initial high-side pressure spike?
Thank you buddy. No, no issues with this refrigerant combo. Highest peak is at 15.5bar, I have never used bypass to date. Static @ 25°C is 7.5bar, goes to 9bar instantly and then creeps to 15-15.5bar for the next 15 minutes. Then it need around 10 minutes to pull back to ~ 8-10bar (depends on ambient temperature). So, pulldown takes about 20-25 minutes from the warm start I think.

@Pieter: No sorry, I don't cool resistors! :cool: But, for the sake of easier tuning I have to persuade my electrical buddies to assemble one for me. No need to drag the computer around.

@teyber: Thanks buddy! I'm quite satisfied, but another 10°C lower full load temperature (courtesy of ethylene R-1150) will make me a happy camper! :yepp:

Best Regards,
Niko

Postal Dude

09-03-2009, 03:50 PM

Very happy to see all your hard work come into fruition. Very nice job. Good to see any shadows of doubt regarding load holding have been well and truley discounted.

I think i need to go shopping :D

tiborrr

09-06-2009, 09:28 AM

Thanks Postal Dude for your kind words! At the moment I am a bit jammed with the faculty related study/work (I'm away from home during this and upcoming weeks) so the ethylene experiment will have to wait another weekend.

Thanks for your support guys! :up:

Best Regards,
niko

clear cmos

09-22-2009, 09:50 PM

hi tiborrr can u pm me your autocascade diagram :)

and what is the black tank near phase separator

tiborrr

10-02-2009, 06:12 PM

Hi clear cmos,

will draw schematics of it tommorrow. The black tank is the expansion tank for the refrigerant which helps reducing the static pressure and start-up spikes when the unit is turned off.

Best Regards,
N.

mytekcontrols

03-10-2010, 08:22 AM

Very very COOL!!! (sorry I'm a little late getting into the game)

Simple, elegant, compact, fantastic execution. I can't wait to see your future test results with additional gases such as R1150.

BTW; At some point you may wish to "water seal" the outside of your poly foam insulation. I know its closed cell, but believe it or not, water will find its way in, eventually. Keep in mind that you have over 100 C difference in temperature from the outside world as compared to the coldest part of the HXC stack. This has substantial "drawing" power on any moisture in the surrounding air. On the Polycold units that I work with, we have had tremendous problems with the poly foam becoming water saturated over time. Even 3-5mil plastic sheeting is not enough (plastics are slightly porous). Of course all this assumes that the unit will be run for extended periods of time (months-years). Probably the best water seal is like what they do on refrigerators, using welded metal sheeting. Although any paintable product designed to keep moisture from leaking through roofs or into basements would work fine.

[486]

07-01-2010, 01:11 AM

Don't know, but do you think If I rather go a bit easier on the CO2 charge and add some R-1150? I think I could get into -85°C league with some positive back pressure, what are your thoughts on this charge?

I know, replying to an old post, thread necromancy and all that :nono: But anyways...

If you have R1150, why not go with a charge of R290 and R1150? No worries about dry ice, and pressures shouldn't be a problem. Remembering stuff I read a while ago some refrigerants will dissolve into others and lower the boiling point of the higher boiling one. One would think that 1150 and 290 would do this well, being that both are hydrocarbon refrigerants. The SLHX might even condense a portion of the 1150 into it's liquid state before the phase sep and then it'll be in the "1st stage" half of the auto, cooling off the rest of the 1150 in the "second stage" half.

You've probably moved on from this build by now though...

n00b 0f l337

07-01-2010, 01:15 AM

Would work well with R600 or R600a in the mix, as that will further sponge.

cdolphin

07-01-2010, 03:07 AM

ultralo1

07-01-2010, 04:34 AM

NOL, not to thread crap, but what does it mean for a gas to 'sponge'?
Anyone know any good reading sources on auto-cascades in general? I am not planning to build one obviously, just trying to understand...
Cheers guys, and great thread, OP.

The only comprehensive guide to autoC on the net is the sticky here at XS. Its Mytekcontrols thread about converting a window unit into an AutoC.

sdumper

07-01-2010, 05:25 AM

;4452759']
You've probably moved on from this build by now though...

This was completed and sold already...

It was a very slick project and turned out beautiful.

cdolphin

07-01-2010, 09:51 AM

The only comprehensive guide to autoC on the net is the sticky here at XS. Its Mytekcontrols thread about converting a window unit into an AutoC.
Brilliant,
Thanks!
/Cory.

[486]

07-01-2010, 11:10 AM

NOL, not to thread crap, but what does it mean for a gas to 'sponge'?
The gasses sort of dissolve into each other, like CO2 into a can of soda. When a low boiling point gas dissolves into a higher boiling one it lowers the boiling point of the higher one without raising pressures much.
I wish more people on the 'net worked on autocascades, they're awfully interesting.

This was completed and sold already...
Oh...

n00b 0f l337

07-01-2010, 12:13 PM

Part of the issue has been securing the gases. Even amongst the r600a/r290/r1150 build idea, the isobutane is not easy to get in a compatible form to be put into a refrigeration unit. That liquid charge amount has to be fairly on target, so a scale is also required.

ultralo1

07-01-2010, 01:28 PM

;4453297']I wish more people on the 'net worked on autocascades, they're awfully interesting.

Oh...

In the refirgeration world, Cascades are considered the formula one level of refrigeration. Autocascades are considered Apollo moon missions in comparison to the cascades. There are very few individuals that can service the commercial autoCs, and even fewer that understand what is happening inside the system. As an example my bosses boss is a registared Proffesional engineer in HVAC/R. He cannot understand how an AutoC works. He just accepts that it does and that I am not pulling his leg when I explain the theory of operation.

[486]

07-01-2010, 03:38 PM

So we're ahead of the curve in the fact that we have multiple people here that understand them? :lol: Dangit, I'm getting the urge to either finish my unfinished one [unlikely as it has been sitting open for a while now, it's mineral oil, but still...], or build a new one from the broken dehumidifier I've happened into [it had a leaky evaporator]. I just gotta find a use for one so that I can justify the cost.

ultralo1

07-01-2010, 03:45 PM

So we're ahead of the curve in the fact that we have multiple people here that understand them

You want find better info any where else.

I just gotta find a use for one so that I can justify the cost.

Build it then find a use for it. :D

tiborrr

05-28-2011, 02:40 PM

I've recieved this autocascade back into my hands therefore I quickly did a recharge job. Straight R-600a & R-1150. A bit risky on paper but it works wonderfully. First charge contained a bit too much R-600a which had a warming effect on my final temperatures. I've vented some of the gas and recharged some more R-1150. Final charge of ~ -90°C (7.5barg HP/0.4barg LP) was achieved eventually.

Pulldown time from warm idle to -90°C is about 12-12 minutes. I've also added some pour-foam insulation which will need to be cut with wire tomorrow.

-90°C on a single-stage auto-cascade ain't too bad I think! :up:

Charging:
http://www.shrani.si/f/3F/j/4aIQDbHP/dsc0397.jpg

First tuning on R-600a/R-1150. Added too much isobutane:
http://www.shrani.si/f/2Z/FT/25oQxxzH/dsc0400.jpg

Final charge later that day:
http://www.shrani.si/f/q/92/78gty4F/dsc0408.jpg

New super compact auto-cascade in the making! :D
http://www.shrani.si/f/1w/Gs/19Rr6LXx/dsc0401.jpg

Best regards,
Niko :up:

n00b 0f l337

05-28-2011, 02:56 PM

Very nice sir, hows the load?
Good to see the r600a/r1150 in action. It's incredible to watch if you have a pile of thermocouples on the stack :)

K404

05-28-2011, 03:16 PM

Full respect for the AutoC, tiborr :)

Also interested in what kinda load it can hold :)

Sometimes I *do* wish phase units didn't have tuning points

sdumper

05-28-2011, 05:58 PM

Tibor did you buy this unit back or are you upgrading it for the owner?

tiborrr

05-29-2011, 02:32 AM

It will probably hold the same load as before, when it was charged with R-600a/R-290/R-744/few shots of R-1150, around 250-270W. Will try to load it later in the afternoon.

The owner of the unit is a dear friend of mine hence I'm just doing him a favor :up: I'll do another auto-cascade in the upcoming weeks, HXs are almost ready :)

Regards,
Niko