Single-stage auto-cascade build

[tiborrr]

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]

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

Gases?

Subcooler?

[tiborrr]

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.

[[XC] gomeler]

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

[[486]]

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]

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]

@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]]

@[ 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]

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]]

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]

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]

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]

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

[Patrickclouds]

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

[tiborrr]

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

[tiborrr]

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]

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]

wow, looks very nice.:up:

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

[SAE]

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

[K404]

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

Hope it goes right first time tiborr :D

[ruffus]

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]

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]

Hell yeah! you go men;)

[bartx]

Nice bulid. Looks very neat :up:

[[XC] gomeler]

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]

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

[[XC] gomeler]

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]

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]

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]

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

[EliTE22]

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]

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]

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]

R507 Doesn´t work in a Auto-cascade

use R290 or R134a

[Ozzfest05]

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]

@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]

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]

Very nice job!!!!!

[teyber]

you can get it! your close! :D

[[XC] gomeler]

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]

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]

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]

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]

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

Regards to Poland,
N. :up:

[teyber]

lol it was 43c here in socal today :(

[sdumper]

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]

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]

jesus christ mate!

this is so good, so compact and so clean!

[tiborrr]

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]

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]

Bloody awesome work there mate :up:

I feel inspired to something similar :D

[tiborrr]

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

[SAE]

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

[[XC] gomeler]

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]

Do You have dummyload ? :rolleyes:

[teyber]

holy smokes complete success!!!

[tiborrr]

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]

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]

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]

hi tiborrr can u pm me your autocascade diagram :)

and what is the black tank near phase separator

[tiborrr]

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]

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.