Single-stage auto-cascade build

[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

[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 And oh, Gomeler - the pressure readings on the gauges are PSI aswell - the closest to the circle center, black labeling.

Best Regards,
Niko

[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.

[SAE]

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

[EliTE22]

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

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.






Best Regards,
N.

[-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?

I've tried new charge with less R-600 and more R-507 instead. The results are as followed:


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



Gaseous line leading from the phase separator:


@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:



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

[sdumper]

Very nice job!!!!!

[teyber]

you can get it! your close!

[[XC] gomeler]

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

[quintus]

Now we need to see how this system handles a load 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 . The ambient temperature was well above 31°C It was a really hot day!

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

[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

Regards to Poland,
N.

[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







Added a bit of R-290/R-600 and got -79°C at 1bar LP/7.2bar HP:


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!
@Sdumper: No problems buddy, i'll draw schematics of it, just remember to remind me about doing that from time to time

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.





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.

[tiborrr]

Brand new (final) charge, same ty me!



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

New results:
125W = - 63.5 ~ -64°C

...
225W = -59.5 ~ -60°C


Tambient = 27°C

Pressure readings - 11.2bar HP (off / discalibrated by about 0.5bar) / 0.6bar LP & power consumption ~ 480W @ load


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!

Best Regards,
Niko