Cascade 4

[bazx]

Parts:

1st and 2nd stages are cascade 3

http://www.xtremesystems.org/forums/showthread.php?t=117279

3rd stage:

little devil cascade case (same as cascade 3)
compressor: Danfoss SC21CLX
Hx: 12 plate
Oil sep: Temprite 900 series
vapo mini condencer
pressure releif valve 24 bar
danfoss pressure cut out KP5
pressure gauge
spun drier/filter
cold ice evap

refigerant R507/R23/R1150

[bazx]

i will be stacking one LD case on top of another for this unit

pic of the 1/2 stage

http://www.benchtec.co.uk/1/cascade4/1/DSC00363.jpg

[bazx]

http://www.benchtec.co.uk/1/cascade4/1/DSC00384.jpg

http://www.benchtec.co.uk/1/cascade4/1/DSC00386.jpg

[bazx]

http://www.benchtec.co.uk/1/cascade4/1/DSC00388.jpg

[bazx]

as the case is being shipped i have begun to put the 3rd stage together
on some 18mm mdf board which will fit straight into the case when it arives

[4Qman]

WOW baz this is going to be really something. I am glad you took this approach and decided to make a 3stage unit. The craftsmanship of the 1/2 stage is really something.

Are you simply going to put the other case on top and remove the roof on the 1/2 stage case , Or cut into the roof for the required space?

Good luck :)

[bazx]

Are you simply going to put the other case on top and remove the roof on the 1/2 stage case , Or cut into the roof for the required space?

yes on top

no need to take the roof off there is already a hole where the old suction return was


Are you hoping for around -75C condensing on the thrid stage?

should be around there was thinking of using a longer cap maybe 2,8m of 0.031

[cold_ice]

Good work!
I hope the SC21 is big enough in the first stage. I wasn't satisfied with the performance of my 4 stage, with SC21 in first stage. But maybe you have better luck.
What refrigerant will you use for the third stage? R14?

[LukeXE]

"refigerant R507/R23/R1150"

Maybe really go with R14, it will be better than R1150 in III stage...

[bazx]

"refigerant R507/R23/R1150"

Maybe really go with R14, it will be better than R1150 in III stage...

maybe better but i dont have it so for now it will be 1150:)


@ cold_ice why did you not like the sc21 1st stage on ya 4

it only has to condence r23 in this unit

[LukeXE]

maybe better but i dont have it so for now it will be 1150:)


@ cold_ice why did you not like the sc21 1st stage on ya 4

it only has to condence r23 in this unit


you should get nice temps, I with -60*C under load HX achieved -103*C@215W loaded with ethylene, you should get similar result :) I hope :toast:

I love your builds

[bazx]

you should get nice temps, I with -60*C under load HX achieved -103*C@215W loaded with ethylene, you should get similar result :) I hope :toast:

I love your builds


thanks luke that's what i was thinking with the extra cooling on the 3rd stage hx i will get the most from the R1150

[bazx]

brazed up the hx and some of the pipe work tonight

http://www.benchtec.co.uk/1/cascade4/1/DSC00390.jpg

[martinjon666]

Hey Bazx I love that little condenser you got on there, where did you get it from if you dont mind me askin?

[bazx]

Hey Bazx I love that little condenser you got on there, where did you get it from if you dont mind me askin?

cold_ice shop here

http://www.kaeltetechnik-shop.at/

[Pete]

Looking good Baz. So you giving up LN2? I might of just gotten my self an LN2 contanier!

[bazx]

Looking good Baz. So you giving up LN2? I might of just gotten my self an LN2 contanier!

havent given up just not much good at it:D

[Pete]

LOL Cascades for you and Ln2 for Thicky eh

[Brettbeck]

I was waiting for this thread to appear Baz :D! Looks great!
Maybe if you are unhappy with the performance of R507/R23/R1150, you could allways change the R23 to R1150 too, it might gain just a little bit. I'm sure FUGGER's 3-stage has R1150 in both the 2nd and 3rd stage.


Oh btw, to anyone in the UK wanting LN2... Try finding it at a decent price LOL! Here we can't transport it unless you have a specialised vehicle. I was quoted about £2.40 + VAT...PER LITRE! AND £35 delivery!! So for a typical 30/35 litre dewar, it would cost well over £100 in total. FAR FAR too much imo, which is why I didn't buy a dewar.
The thing is there isn't the demand for small amounts, which is why it's so expensive. Gas suppliers such as BOC & Energas only want to deal in huge quantities, around 240 litres or more...

[K404]

BOC only ship to non-residential addresses as well, at least thats what they told me, I didnt even get as far as prices. :(

[bazx]

2nd stage is done with an unloaded temp of -81

http://www.benchtec.co.uk/1/cascade4/1/2/DSC00448.jpg

[bazx]

http://www.benchtec.co.uk/1/cascade4/1/2/DSC00451.jpg

http://www.benchtec.co.uk/1/cascade4/1/2/DSC00452.jpg

[bazx]

also got the 3rd stage finised up brazing and some nitrogen in for leak testing

tomorrow i will put the R1150 in

[bazx]

thanks tom

i am a lil worried it is all going to easy

[LukeXE]

Nice, can`t wait to see results !

R23 on II stage, am I right ? I would try R1150 on II stage and III :)

[bazx]

With that temperature on the second stage i'm guessing that you've sized the second stage for pretty high capacity?


to be honest it was a shot in the dark 2.6m of 0.031 as i have not had much luck with captube and hx before i went for a length i have used before

also i think LD and clod_ice have used this length with there plated hx

and as i have never worked with r1150 before i dont no what kind of a hit the 2nd stage hx will take

[bazx]

Nice, can`t wait to see results !

R23 on II stage, am I right ? I would try R1150 on II stage and III :)


yes r23 on the 2nd

i will try both:)

[Brettbeck]

Good luck baz :D. When are you getting the 2nd case to mount on top?

[bazx]

Good luck baz :D. When are you getting the 2nd case to mount on top?

i have it now but i need the cascade for saturday so it will have to wait now

[expansionvalve]

That's quiet an impressive looking toy bazx, nice :)

[4Qman]

A masterpiece :toast:

[bazx]

been trying to tune the unit but have had a few problems

some how some oil got passed the danfoss oil sep on the 2nd stage
this lead to strip down of the unit

i have swaped out the second stage compressor and replaced it as i was not happy with it,cleaned out the oil cap tube re done some of the pipe work

just got the unit up and running again and am now trying to tune it again

this is much more difficalt then i thought

every time you make an adjustment at the r1150 there is a knock on with all the other comp and hx temps

i have been getting some nice temps tho 1st -38/2nd -80-/evap -102

i am going to shorten the evap cap a bit tomorrow

[kayl]

bazx do you use a section of capillary line on the return feed after the oil seperators? have seen cascades not run well when float opens.

[bazx]

bazx do you use a section of capillary line on the return feed after the oil seperators? have seen cascades not run well when float opens.


i use 1/4 copper return too the service port

do you think cap would be better?


i just dont now how the oil got past the sep but it is a worry

i might change it for the temprite same as 3rd stage dont have any problems with that unit

i must say i am enjoying the challenge of 3 gasses it might take me 2 months
to get the hang of this:D

[kayl]

i use 1/4 copper return too the service port

do you think cap would be better?


i just dont now how the oil got past the sep but it is a worry

i might change it for the temprite same as 3rd stage dont have any problems with that unit

i must say i am enjoying the challenge of 3 gasses it might take me 2 months
to get the hang of this:D


its worth a try, so dont loose too much suciton that way when open. i just used a few foot.
1st stage would be the hardest to tune i would imagine to tune

[bazx]

http://www.benchtec.co.uk/1/cascade4/1/3/DSC00464.jpg

http://www.benchtec.co.uk/1/cascade4/1/3/DSC00462.jpg

[bazx]

http://www.benchtec.co.uk/1/cascade4/1/3/DSC00466.jpg

http://www.benchtec.co.uk/1/cascade4/1/3/DSC00468.jpg

[bazx]

http://www.benchtec.co.uk/1/cascade4/1/3/DSC00469.jpg

half way through 06 with a QX6700 @4.2 vcore 1.7 for load all 4 cores with single 8800gtx on air the second stage hx had collapsed to -20

http://www.benchtec.co.uk/1/cascade4/1/3/100.jpg

http://www.benchtec.co.uk/1/cascade4/1/3/DSC00471.jpg

[bazx]

if you look at the DT200 on the left you can see the 3rd stage hx was up and down like a yoyo

this is the R23 stage and oil is getting in the cap tube but i am happy that i am just one oil sep away from a usable cascade

all the above temps were with the evap hooked up to a qx6700 running in the bios or windows


@kayl i would try it if the sep were a lil easyer to get too but as it is such a job to get in there i will just change the sep now

[Brettbeck]

Nice baz :), hope you get it all sorted.



half way through 06 with a QX6700 @4.2 vcore 1.7 for load all 4 cores with single 8800gtx on air the second stage hx had collapsed to -20


Are you sure? So it was condensing R1150 at only -20c?!

[bazx]

Nice baz :), hope you get it all sorted.



Are you sure? So it was condensing R1150 at only -20c?!


the thing with plate hx is you can only measure the temp at the suction return
or at the line in

that temp is at the suction return just as the refrigerant leaves the hx

so it will be colder in side the hx but not for long

[blind_ripper]

great 3stage bazx , good luck wit the benching there m8 :)

[Cupcake]

Wow, nice work

your gonna have some fun with that :D

[- Feedback]

the thing with plate hx is you can only measure the temp at the suction return
or at the line in

that temp is at the suction return just as the refrigerant leaves the hx

so it will be colder in side the hx but not for long

Is your second stage still cap tube? If so, how is your oil seperator holding up? I could see if enough oil got through it clogging the second stage and starving the 2nd-3rd stage HX. Cyclic refrigerant operation happens for other reasons too such as improper charging and sometimes more subtle roots. Hopefully it's easy to fix like the problem with cascade 3.

[Gray Mole]

Right, going to go over this for you, and anyone else who's listening as well.

Comparing performance of a linear HX and a parallel HX can ONLY be done via the outlet temp of the liquid, NOT the outlet temp of the HX's cooling stage.

If you look at the outlet temp of the cooling refrigerant (high stage) in a linear HX (such as tube in tube) you can use a similar formula to an evaporator to determine the oulet temp of the liquid being condensed. For example, if you have -35c as the outlet of the boiling refrigerant, you may have approx. -20 condensed liquid yeah?

Well in a plate HX or 'series' HX you have as many independant HX's as you have plate areas.

That is, if you have a 20 plate exchanger, you have 10 HX's.

So measuring the output of the high stage refrigerant boiling off is meaningless. It's entirely possible that you'll be colder on the liquid outlet than your returning gas.

So, you MUST measure the liquid of the HX outlet to determine both efficiency, pressure, and load response.

This makes a PT chart that much more important, as you need to be sure that the high pressure refrigerant, especially R1150, is condensing at the temp. and pressure you're targeting.

For Ethylene, you'll have 255psi (approx) at -20.

Is that so bad for a load pressure?

Not really, but anything you can improve on that is great.

Do you have -20 liquid Ethylene temp?

You don't know, because the HX gas outlet and the liquid outlet have NOTHING to do with each other in a series HX that is not fully flooded.

And to be honest, you DON'T NEED a full flood of refrigerant in a plate exchanger, and sometimes you don't want one either.

A plate exchanger is VASTLY more efficient than any coax/tube in tube setup. It can do more in the first couple inches than most tube in tube setups can do in their whole surface area.

So measure the liquid outlet, monitor THAT for the load response and capacity of the high stage, and you will know for sure where you stand.

If the liquid temp continues to increase, sure you need to change the capacity of the high stage.

If the liquid temp goes to say, -20, but remains there under high load, and you're happy with 250 or so PSI as your final stage's load pressure (and that cpu is a HIGH load cpu, as you probably know) then you need to change nothing.

I've got my 2 stage cascade nearly done with a 14 plate HX and I went through the SAME thing, wondering why I couldn't get a full flood without overcharging with captube.

When I started to monitor the liquid outlet I realised that I didn't need one.

So yeah, Hopefully I made sense there, but as more people are using Plate HX's it would be nice for them to know that a slightly different way of thinking about, and approaching it, is necessary as they behave in a slightly different manner to the HX's that most have been using for so long.

Cheers

Gray

[bazx]

hi gray i have just pulled out the hx on the 3rd stage and it is full of oil

what do you think will cause my 12 plate hx to be full of oil

[Gray Mole]

Dam, that is a pain, and something I've been finding myself.

I was thinking it may be the Danfoss oilsep's I've been using, but I think that the more likely cause is either the oilsep is having low temp issues with 'sticking', the oilsep could have failed completely (not that likely unless it was used and not new) and the most likely problem? Too small.

If the oilsep can't quite keep up with the oil flow, and in larger systems you CAN get a high rate of flow, then a larger oilsep designed to keep up with a high rate of flow is needed.

This is part of why the 'home made' oilseps can work really well. They're made incredibly large compared to the manufactured units. They can store huge amounts of oil and in some cases tend to separate better.

I'd say to check the operating temp of the oilsep first, to ensure the oil isn't either too hot or too cold to function as intended within the oilsep.

Checking for a completely 'stuck' oilsep is quite easy.

If your HX is filling though, it may also be an oil incompatibility problem but with ethylene it really shouldn't be. It drags oil around quite well.

It could also be an issue with too much oil in the system.

Compressors are overfilled when new. This is to allow for system size. The oil moves, so they allow for more than is needed to compensate for that, and normally our systems are WAY smaller than the size of the systems that compressors are really intended for.

I would be inclined (and have done so before) to dump the oil from the HX and put it back. That should get rid of the 'overflow' oil and still have enough for proper lubrication of the compressor itself.

A compressor will 'throw' FAR less oil around when it's not filled right up.

Otherwise, what oilseps are you using again? Size, and codes?

There is a chance you'll need to use larger ones to keep up with the oil flow but I think that the biggest problem is a small system with a large amount of oil, and if you remove some of the oil (not too much that you starve the compressor) then the oilseps will likely function in a way that keeps the oil out of the system.

There is ONE thing I would recommend though.

I've been switching to AB oil in all of my cascade Low Stages recently, and it's been saving me a lot of grief.

I have Fuchs AB synthetic, which is guaranteed miscible to -70, and they state that it's quite likely to work fine even lower in temp.

This can mean that on initial startup, most if not all oil will 'cycle out' before low temps can freeze it.

I've been having a lot less hassle on the 2 prototypes I've been working on (very little, but I'm almost done the 'customer stuff' so will be returning to the fun stuff very soon :D) due to this oil in the Low stages.

I've been using it exclusively in systems that require an oil change and it's been remarkable. I've seen a couple of degrees colder due to the oil flowing far better.

As far as oil level goes though, the NL11F is a good example.

It comes with 330ml new (roughly)

If you drain off to about 250ml and then install into a new system, you'll get far less oil issues even in a single stage, because the system is so small you don't need the 'extra' as you don't see nearly as much pipework in our systems as you do in a large Airco unit.

So yeah, I would try that first, lower your oil levels in both Low stages. You may find that cures a lot of oil problems as the 'flow' of oil will be reduced, so the oilsep's won't be fighting the oil nearly as much.

If you get oil issues regardless of your oilsep, switch to a low temp AB synthetic (it tends to be quite compatible with other oils as well) and the small amount that makes it past the oilseps will tend to make it through because it doesn't freeze nearly as badly.

Cheers

Gray

[bazx]

you may well be right about the amount of oil in a small system and the oil you mention sounds like a good idea

Danfoss OUB1 oilsperator is used on the 2nd stage and this is the one that is letting oil past and is well within its operating range

the good thing is i am use the oil sep from cascade 2 in the 3rd stage (1150)Temprite 900 series and it is working very well

but there are differances in there set up the danfoss did not require a pre fill of oil where as the temprite did

also the the temprite is a big sep (4 inch dia) which would fit in with your earlyer comment

so i am now going to get another temprite to replace the danfoss

[|RickY|]

good work bazx, one thing i'v thinked as 1 start thinking on my 3stager is an oil return cap on 3rd stage hx!, i open that valve betwen cascade working times, when i start 2nd stage or so, before hx becomes cold just becouse some oil that was not catched by separator needs to climb all the hx @extreme temps.

1st stage and 3rd stage have the gravity help

[bazx]

oil is the main fight with the 3 stage

i was talking to esdee and he surgested i use bigger dia cap tube on the 3rd stage hx

now i have 2.6m of 0.031

but i might try 0.042 what do you think


i may also fit a cap return as well for any oil that gets in the hx as it is a pain to remove once unit is compleat

[Brettbeck]

Damn it must be such a nightmare building a cascade like that, and then finding you have problems and it needs taking apart :(.

[bazx]

Damn it must be such a nightmare building a cascade like that, and then finding you have problems and it needs taking apart :(.

it is a pain for sure

well got the unit working and stable after fitting the new temprite 900 oil sep gased the 2nd with R507 and ran it for an hour just to make sure all the oil had returned back to the compressor

then vaced it down and regased with R23

just had the unit running for 2 hours without load on the evap just to make sure that all temps and pressures would sit stable before i moved it over to the bench
and hooked it up to the QX6700

load testing tomorrow now

some picks

http://www.benchtec.co.uk/1/cascade4/1/4/DSC00498.jpg

[bazx]

http://www.benchtec.co.uk/1/cascade4/1/4/DSC00502.jpg

http://www.benchtec.co.uk/1/cascade4/1/4/DSC00505.jpg

[bazx]

best unloaded temp

http://www.benchtec.co.uk/1/cascade4/1/4/DSC00496.jpg

[bazx]

He he, nice one Baz!

You broke half room normal temperature! (150K) :D

Did that cap tube length work out?

Tom

i did not have the time to try in the end as i want to do some benching before this ln2 evaps from last week:)

i have a pot reay to go on a 8800gtx

[Brettbeck]

i did not have the time to try in the end as i want to do some benching before this ln2 evaps from last week:)

i have a pot reay to go on a 8800gtx

Hey Baz, wher'd you get LN2 from in the UK :confused: ?


Nice to see your cascade up and running properly :D!

[bazx]

Hey Baz, wher'd you get LN2 from in the UK :confused: ?


Nice to see your cascade up and running properly :D!

B.O.C

[Brettbeck]

You mean the huge 240+ litre tanks? Or do they actually let you buy smaller quantities?

[bazx]

You mean the huge 240+ litre tanks? Or do they actually let you buy smaller quantities?

hehe 50L here

http://www.benchtec.co.uk/1/ln2/ln2.jpg

[Brettbeck]

Isn't that a 25litre dewar :p:? I could swear I saw that on eBay a while ago!

Rofl at some of those pictures baz, I liked the saussage roll experiment :D!

[wdrzal]

Great work, build it not only functional but make it look NOT like a crows nest and build it safe,all stages that require safety devices, You and your customer will both sleep better at night. Sign your work as a painter signs his creations. Be proud of a job well done.

Walt

[bazx]

i was looking at this unit last night and thought it could
do with finising off

things left

fit the case to the 3rd stage

fit an extractor fan to the 1st and 2nd stage same as the one below make up safty guard

fit switches/tempdisplay/gauge to the front pannel

new things

a water cooled DSH to the first stage same as the one on cascade 5

change refrigerant from R507/R23/R1150

to R507/R1150/R1150



here is the top case still with its cover

http://www.benchtec.co.uk/1/cascade4/1/c4update/stage3/IMGP0015.jpg

http://www.benchtec.co.uk/1/cascade4/1/c4update/stage3/IMGP0016.jpg

[kayl]

that is a very nice cascae there baxz, cant wait till tomorrow with QX6700 benching ;) good luck

[bazx]

that is a very nice cascae there baxz, cant wait till tomorrow with QX6700 benching ;) good luck


hehe thanks

just fitted the case and i wish i had done it earlier now

just got to make up the water cooled de-superheater coil for the first stage

after looking how tight it is for space in there i will be mounting it in the top case

http://www.benchtec.co.uk/1/cascade4/1/c4update/stage3/DSC00818.jpg

[theclash]

That's one impressive unit! Keep it up!

[bazx]

That's one impressive unit! Keep it up!


thanks clash:)

just made up the water cooled de-superheater coil 1/4 in 1/2 and fitted it

was quite tricky getting it in

just need to vac down and re gas

http://www.benchtec.co.uk/1/cascade4/1/c4update/stage1/water/DSC00822.jpg

[bazx]

http://www.benchtec.co.uk/1/cascade4/1/c4update/stage1/water/DSC00824.jpg

http://www.benchtec.co.uk/1/cascade4/1/c4update/stage1/water/DSC00832.jpg

[4Qman]

A master piece, i shall be finishing mine when i return from holiday in 2weeks Baz. Seeing this just makes me all excited.

[n00b 0f l337]

:drool:
Me want case.

[bazx]

A master piece, i shall be finishing mine when i return from holiday in 2weeks Baz. Seeing this just makes me all excited.


pauls coming over sunday with a gtx to get the mounting made for cascade 5
he can bring me upto date with your build:)

lol noob i have had this case for 9 months so its about time i put it on:D

[4Qman]

pauls coming over sunday with a gtx to get the mounting made for cascade 5
he can bring me upto date with your build:)

lol noob i have had this case for 9 months so its about time i put it on:D

Well not much on build l8ly due to work but it will start again now i have paid off 2 holidays. Its finished but 1st compressor is shabby. :shakes:

I would have certainly come along with paul sunday if i was here, a lads holiday taking 1st priority :yepp:

Again nice build mate and once mine and pauls cascade is done im sure ill be ing seeing you ;)

Dave