3 stage cascade

[cold_ice]

Last week I started to build a three stager. I had most of the parts laying arround, some are from my first cascade

The parts
First Stage:
Elextrolux MS26TB compressor 1 3/8HP
1,1kw condenser
Castel 4308/2 filter
3,6m TC-36 captube
5m HX 6mm in 15mm tubing
Carrier suction accumulator
R507a
Dixell XR10C Thermostat (PTC probe)

Second stage
L'unite CAJ4476Y 1 1/6HP
Desuperheater
ESK oilseparator
Castel 4308/2 filter
CPEV or TC-36 cap tube
5m HX 6mm in 12mm tubing
manometers high and low side
R1150

Third stage
L'unite CAJ2432Z 4/5HP
Desuperheater
Henry S5180 Oilseparator
Danfoss DLX052 filter
CPEV or TC-36 cap tube
chilly1 evap Rev.3
manometers high and low side
R14 or maybe Krypton

This is how I placed all the parts last week.



Then I made the heatexchangers, after that I mounted the first parts on my plate.











Next step was insulating the heat exchangers. They got really big...







Working on the first stage









Today I finsihed the first stage
















I'm not sure whether I should use R14 or I should try Krypton in the third stage. Anybody tested Krypton? I heard that it should be expensive, but I dind't find much information about it.
Here is the pressure chart, maybe a three stager is not enough to condense it at reasonable pressures...



Furthermore I'm not sure if I should use captube or a CPEV in the second and third stage. In my last two cascades I used captube and I had very good results. I never had any luck with any kind of valves

[Fhqwhgads6680]

wow great work! I really would like to do a cascade in the future once I gain enough knowledge (and money lol)...Can't Wait to see finished product!

[Gray Mole]

Well first of all, nice setup I like the progress, and the HX's look great. Bit big but should do the job for you.

I am preferring the captube myself, I've struggled using TEV's myself and my best cascade has always been plain old captube so far.

For the Krypton though I just don't know.

Working it out to a -85 HX best case scenario, that lines up with 30bar vapor and I'm assuming that's not even dew, but bubble for condensing pressure, and that's awfully high. I have no idea what kind of gas it is for cascading but the mass at 83.8 seems ideal. I just think the temps you'll get one the HX won't be enough to get the condensing pressure down far enough.

Looks like a 4th stage gas to me.

R14 is more ideal with a mass of 88 or so, though even that is going to need -80 or better to condense safely as at -80 your looking at 15bar or more to get it to condense.

I don't know what kind of HX temps you'll get with R1150 as it's pretty light for mass and might not get you the HX temps you're looking for, but hopefully someone with experience on 3-4stagers can help you out with that.

Nice so far though.

I've been considering the 3stage option, thinking about 404a/R23/1150 for the gasses, seems that the mass of R23 would be decent for keeping the HX temps stable from 2-3 but I'll be looking at that later on in the year.

Cheers

Gray

[Cpt Twitchy]

Gray, could possibly getting a 1/2hp compressor and using that in the first stage and then the 3/8 on second stage help for better HX temps if that fits his budget? I don't know alot about cascades but they seems like it would help some.

Man you are going to get some cold ice on that evap hehe Looking very clean and well put together. And from my little knowledge of Cascades I would say go cap tube. As for Gases I say Shoot runmc a PM as he has built a few 3 stage cascades.

[the_new_guy]

amazing dude, i love it!!

[cold_ice]

@Gray: I hope I can get the second HX down to -90° loaded, the compressors are real monsters, so it shouldn't lack of compressor power. -90° would be a condensing pressure of about 23bar with krypton, still a bit high. Don't know if it would work. But nevertheless I must check out the price for kyrypton, as it seems it is a really rare gas.

[Gray Mole]

@Gray: I hope I can get the second HX down to -90° loaded, the compressors are real monsters, so it shouldn't lack of compressor power. -90° would be a condensing pressure of about 23bar with krypton, still a bit high. Don't know if it would work. But nevertheless I must check out the price for kyrypton, as it seems it is a really rare gas.

hehe with your second stage coming in at over 1hp you're certainly not lacking the power

There's certainly Krypton available and if it's a reasonable price then it could be considered, I suppose it just depends how low you can get that secondstage to maintain for temps.

At least unloaded and running I could see it working to get a very cold 'screenshot' but under any load it's very difficult to say if the pressure of the Krypton could be kept low enough.

At -90, if that's possible to maintain, R14 would be a breeze to condense. So at least there's that to fall back on for the 3rd stage. I suppose if it looks good for Krypton price wise, you've still got a lot of room at looking at a fourth stage later. My R23 cascade only runs a 1/3HP 2nd stage compressor and does a fine job with 150w heatload at -75 or so, so a fourth stage at around 3/4HP or even 1/2HP would give excellent results I would think.

It's a heck of a project though for the power of the compressors you're using. I hope they all work and do the job, as I really struggled with the 2HP compressor in my Autocascade with compressor temps, and kicking out due to them getting too high.

Even with R14 you're looking at a very usable -125c or so, quite possibly loaded. If you added a fourth stage so that you could be certain about Krypton being safe in the final stage, I would imagine that -150c temps would be possible. The only real quiestion mark about Krypton is how it works as a refrigerant gas. What oil? Are their any other issues with it? Does it react badly with oil carrier gasses, or make certain oils break down?

Big compressors and frosty temps Just what we want to see around here

Gray

[cold_ice]

Yes you're right, I found no information on using Krypton as a refrigerant. Maybe the experienced here can tell us something about it.
But anyway when I use R14 I have to think about the oil separator, I read that it might be a problem because the R14 "takes out" the oil of the separator.

[the_new_guy]

i heard R14 is really bad at load, huge variation in loaded and unloaded temps.

Krypton's atomic structure is very stable. It has just enough electrons to fill its outer 'shell', so it doesn't tend to combine with other elements. Since it doesn't combine with other elements, it doesn't take part in chemical reactions, so it will not burn, cause corrosion, or do other chemical-like things.--http://education.jlab.org/qa/krypton_01.html

[johann]

Hi,

@ Cold Ice. I think you have the compressor ratings wrong.

I pulled up specsheets of all of them....

Elextrolux MS26TB compressor 1 3/8HP

This compressor is not 1 3/8HP, its 3/4hp 26cc

L'unite CAJ4476Y 1 1/6HP

This compressor is not 1 1/6HP, its just over 6000btu, I would say around 1/2HP

L'unite CAJ2432Z 4/5HP

This compressor is not 4/5hp, its only 2700BTU maybe 1/4 or 1/3 hp

Just thought this would be good to know before you build it so that you can replan the system.

Also I have a similar CAJ 5000btu lunite compressor and its extremely loud and performs really bad, its 3/8hp

[cold_ice]

Sorry but your spec sheets are wrong.
Here's the list from electrolux, the MS26TB is 1 3/8HP



And the CAJ2432Z should be 1/4HP? Lol thats a joke isn't it, thsi baby weights about 18kg and it pulls about 2,5amps at load.
Where did you get these spec sheets, link?

[Unknown_road]

@gray mole: bubble and dew point are the same for pure gasses...

krypton, don't know much about it either but I think it is really expensive.

@ johann: the MS26FB(LBP) is 3/4hp the MS26TB(HMBP) is 1 3/8

[johann]

Perhaps my specsheet on the electrolux is wrong but the l'unites are not what you think.

The CAJ4476Y IS 5/8HP

http://www.frigorafen.it/Catalogo/Tav-A5.pdf

http://www.ecr-ref.com/paulus_fr/tel...182_s215_f.pdf

@cold ice - I was trying to provide helpful info, then you come with that attitude.

Please when you are wrong then admit it.

You think your compressor is 1 1/6 HP and its not. And that could make the cascade not work so I was just thinking of helping.

Good luck I cant wait to see the results!

[skirms_fr]

cold_ice why dont you make a 4 stage ?

metane in the fourth stage

[Comp-Freak]

johann is right. You can see the BTU rating in the l'unites part number.

CAJ4476Y = 7600 BTU and CAJ2432Z = 3200 BTU

[cold_ice]

Perhaps my specsheet on the electrolux is wrong but the l'unites are not what you think.

The CAJ4476Y IS 5/8HP

http://www.frigorafen.it/Catalogo/Tav-A5.pdf

http://www.ecr-ref.com/paulus_fr/tel...182_s215_f.pdf

@cold ice - I was trying to provide helpful info, then you come with that attitude.

Please when you are wrong then admit it.

You think your compressor is 1 1/6 HP and its not. And that could make the cascade not work so I was just thinking of helping.

Good luck I cant wait to see the results!

I didn't want to be rude to you, I appreciate when somebody want to correct me if I have the wrong information.
The Electrolux compressor has 1 3/8HP, thats solved now.
The CAJ2432 should has 3/4HP as your catalog says. I did the calculations on this compressor one more time and now my result is 3/4HP too. So actually more power than my first calculation
The only thing is the CAJ 4476, my spec shet says it pulls more than 800w, and your sheet says that is hat only 5/8HP? Weird...


But I'm very happy when I get information to do a better job, thanks for this.

@skirms_fr: Good idea. I might get some plate heat exchangers to make it a little bit smaller, so maybe I can fit a fourth compressor on the plate. I have a Danfoss SC21CLX, a Danfoss SC18CLX and two SC15CLX here.
Maybe the Electrolux for the first stage, SC21CLX for second, SC18CLX for third and SC15CLX for the fourth stage?
Man I'm getting happy when I think about four stages
More input to replan the thing is welcome

[wdrzal]

how are you calculating the hp?

[skirms_fr]

go for 4 stages

[johann]

@ cold ice

Great I hope you find the rigth info so your cascade works good. Go for 4 stages it would be great

[Unknown_road]

I would try to prevent the use of r134a compressors, r404a compressor can withstand much higher pressures.

Leistungsaufnahme isn't exactly the same as motor power

[Unknown_road]

cold_ice, I did some calculations for krypton and these show that you'll need about twice the displacement as with a normal refrigerant to get the same suction pressure.

[cold_ice]

Thanks for that. But I'll go for 4 stages now, R14 in the third and Methane in the fourth stage. Hope I have time to work on it tomorrow.

[wdrzal]

I hope your installing pressure releif valves, pressures can get away from you pretty quickly, Set a good example and work safe.

Nice work guys !!!!!!!

[cold_ice]

I will install pressure gauges and pressure cut out in all stages except the first. I have to get pressure relief valves, I only have one here.