Mini-Box Cascade

[Gray Mole]

I was supposed to be wiring and testing the controller today, but I just couldn't resist getting started on one of 2 cascades I'm putting together.

The other one will have a TEV/CPEV setup, but this one is going to be 'old school' with captube and home brew oilsep with a handvalve. Mainly because of the space issues. You'll see what I mean...

Got ahold of a cool little condensing unit, though I had to get rid of the barrel fan, it was too loud and got in the way of the small size. The curved condensor is awesome though, and I already have a couple of ideas for fan setups. We'll see how that happens. Only the first stage is set up, and it's R290 for testing until I'm back at work and have access to 404a or 402a. I'm thinking colder though, since the condensor is ideal for that kind of thing.

Specs

1 x Toshiba 12cc Rotary 1st stage
1 x LG 12cc Rotary 2nd stage
12000 btu curved condensor
18 plate HX
6' .040 captube 1st stage

6' braided flex is sitting there for the 2nd stage, planning 6.5' or so of .031 captube, though I may adjust that.

Likely 402a 1st and either R23, Ethane or Ethylene for 2nd, depending what I get first. I don't have any gasses here, not even Co2, so I'll have to be patient. Hoping to have one of them before the end of the week, but we'll see. Only gas my suppliers use for HVAC here is 508 and that's 4k+ for 5 kg so it's not going to happen.

Found a good supplier but need to set up an account and all that. Hope it goes quick.

That's about it for now, running a little overcharged and terrible condensor cooling now, but it's about -43c on the HX, around 0psig. 402a will be far better and once the shroud is made up for the fans it should bring my head pressure down, and temps along with it.

With R290 and terrible fan power it's running 160psig/0psig sitting there, no load other than being uninsulated.

So I'm happy and leak free so far

Hope to get it mostly done by the weekend if gas allows, and make the case into something pretty afterwards.

The chassis frame is about 1' Square. Everything fits though, just barely, with room for insulation and wiring, and I'm hoping to get the oilsep into that little empty space next to the HX. Should be a perfect fit. Already have the pipes ready for it, but I need to braze it tomorrow if I can. All being well, I'll have the second stage finished and ready for gas tomorrow.

I have a few evaps here, but I'm not sure what to use. Probably either the Kayl or the other stepper that's here. Not sure, but probably the Kayl will be used. I like 'em.

Once the workings are done and the fan shroud ready, I've got exterior panels in mind, perspex will do nicely, since the fan/exhaust will be strong enough to prevent the heat fading and staining. I may go with a white panel setup, but I'm not sure. White/blue LED kind of motif sounds nice.

Gray

[sdumper]

That looks frosty
Love compact builds!!

[Buckeye]

Hey Gray that is looking real good man. Nice !

[Sn0wm@n]

ohh so frosty


gotta love phase change builds

[Gray Mole]

Thanks

Decided to adapt the barrel fan back on, since it's already set up for it (big hole on the top) and it works pretty nice so I think I'll use it.

It adds around 5" on top but it's not too awkward and I can set up the panels to pretty it up. I figured out the low fan setting on it, and it's around 200 cfm, but less noisy than the compressor at that speed so I'm happy enough with it.

High pressure came WAY down with that, still frosting about 1" from the compressor, or just after the accumulator. 110psi high and -8psi low with the fan at low speed. -50ish HX temp.

I just need to cut off the fan shaft upper, it used to run a dual fan for the air evap. There's 3 posts up top, which I can use for the top panel, should make it pretty sturdy. 110v fan means no extra psu or fan costs too, that's a plus. Comes out a small hole so if a person wanted to, they could put an A/C window kit (like on a portable A/C unit) on there to get the hot air out of the room. I actually have one here I think, may just build that into it.

Only down side is that the fan blows out above where it's taking air in so I'll have to louvre the exhaust upwards so it's not taking in hot air. Using a hose and window kit takes care of that, but it's nice not to 'need' that to use it.

I had to give up on the 'guts' being that pretty with the space being so confined, but the panels will make it look nice on the outside, and being a 'sealed' box environment it should keep a lot of the compressor noise inside too. Fan is quiet enough, so maybe under 40db if I'm really lucky. We'll just see how well I can soundproof it. Not expecting miracles, but cascades are noisy creatures by nature, not a lot you can do about it.


Gray

[Gray Mole]

Oh yeah

I'm thinking I'd like to automate the stages, never liked having to switch on the 2nd stage manually.

I have a couple of old mach1 controllers and while they really did suck for a SS, I think it should work to switch the 2nd stage when it reaches temp on the 1st. Been a long time since I reprogrammed one of those so I don't know if I can or can even figure it out but I have a pdf on the Carel, so we'll see if it's doable.

Unless I can score a really cheap Oilsep fast, it'll just have a home made one with a handvalve so it still won't be 'plug and play' really, though I'm toying with the idea of a captube return, restrictive enough that it doesn't affect the capacity. I don't know if I'll use it that way or not, but I've been looking at that, and maybe I should use the system I was thinking of before, maybe 10' of .031 captube, and a decent charge of something like butane to autocascade the oil out of the evap circuit. I think the oil would partially plug the captube, and run it so slow that it would have virtually no effect on the evap.

More I think of it, that seems the logical way. No valves/headaches. Only question is whether the oil would move enough with .031. Would a longer run of .040 or even bigger be a better idea? I do think I'll test it that way, but braze in a valve anyway, just in case.

Gray

[sdumper]

PIDs work nicely for automating and they are cheap...

[Gray Mole]

What a letdown.

Got the oilsep in, and I chickened out and just used 1/8 pipe and a valve. It's a basic one, 2" tube and copper wool.

Did a pressure test and fixed the one small leak on the tube, then noticed a leak on the flex I didn't worry about it, since I'd made it up ages ago but the line inside the braid is cracked in 2 places must have gotten mangled when I moved.

So I've got to get another flexline together. Only had the one cascade line, and if it's that bad it's not worth stripping and fixing, though I'll keep the braid when I tear it apart.

So she's on hold until I get more line, but I still haven't heard if I can get Ethylene here on not. Canada's funny about flammable refrigerants so it may be back to the old standby, R23. Shame, the 1st stage should have some pull with 402a, but even R23 should get me back in the -100c club again and with a little luck be around -85 to -90 with high load. The compressors are solid, and the first stage should hold -40 or better with 23 on it. I'm hoping to see -40 actual condensing temp if it holds up well.

The whole thing is just a refresher course for me, since I've been working in refrigeration but it's the boring day in day out repairs and installs. Not really the glamour and fame that I was led to believe


So we'll see what I can get by the weekend. I've got a short (3') line I could use, but that's pretty short for a cascade

Tomorrow's a big cleanup in the shop though. Getting some dirty looks from the roomies, since they appear to consider my 'work' to be ill conceived abominations, or something like that. Plebs.

Most of the fun is actually going through it all though, whether it even runs or not or ever sees a cpu isn't what get's me. The challenges, the problems, the smell of brazing rods.


Gray

[Gray Mole]

Well I Just checked the guages and it's held a full 200psi test overnight.

That's AFTER I removed and brazed shut the evap flex and captube of course, and since I did a cap in tube setup this time (why is it that EVERY time I do that, something like that happens?) I'll probably just do up a full new line and head for this. Once I have a flex line that is

So once I clean up the shop and insulated the lines and HX I'll throw up the pics of it. Hoping to get some panels today too if all goes well, and get a start on the exterior.

Gray

[lesstutrey]

love small builds like this. Very nice work.

[runmc]

Lots of fun here Gray

[sdumper]

Give Ruffus a ring he has a source for r1150 in Ontario somewhere.

[Gray Mole]

Thanks

This one's just a bit of fun before the 'real' cascade later on, but it's fun I get to refresh myself of the details. Captube cascades can be pretty good to work with though, if you're lucky or skilled enough to get just the right lengths, sizing, etc for what you need. Hopefully I'm lucky

I even found a length of flex to match some SS braid I have, and I have the flexline done and tested. I even went out to the Garage in my housecoat to check if it passed the pressure test overnight. Hairy legs are so attractive

So I just need to braze on the head, and the line into the 2nd stage, and I'm ready for gas.

I MAY have hit lucky with another supplier here for Ethylene, hopefully that pans out. Would be nice to deal locally with the supplier. They said it would come from Ontario though probably just where the main plant is where it's produced here.

If I can't get anything before the weekend I'll see about picking up a small Q of co2 so I can run some testing. Probably better to do that anyway, in case there are any issues, since co2 is dirt cheap and handy to have around I suppose.

Oh, on another note I was talking to the guys about pressure lines, and they said that the copper/bronze flex with matching overbraid has a 500psi working pressure limit. That's interesting since it's so easy to braze. Said that the smaller pipes (1/4 id) have that rating.

I'm thinking I'll try that out on the next one. 200psi is the max static I ever use, +/- a couple, and 500psi is a long way up. Seems ideal. I made a bunch of units with copper flex way back when and not one of the lines ever failed. More than I can say for the SS flex. May not be as strong, but seems to be less likely to crack being softer I suppose.


Gray

[Gray Mole]

Well it's all brazed up and seems to work

I ran 290 in both stages and watched the HX and it was doing it's job. Low side in at -40 High side out at -33. Couldn't get the head about 70psi (which is understandable) but At least now I now it's together and working.

Ready for the gasses that are going in, and of course the insulation. I need to pick up some larger tube, more tape, and I want to replace both high side access valves.

I did get great news on my Ethylene, it's ordered and should be here in 1-3 weeks, hopefully the sooner. They have stock of the big bottles but not the 5kg size. I'm happy enough to wait as long as I know it's coming.

I have most of what I need for the next cascade too, so if it goes well I'll be able to gas both up at the same time. I also have a bunch of little projects on the go too, and I should really finish them.

I'll update after I've insulated and made up panels, there's nothing exciting to see just yet and it's a wait for the gas so no point in taking pics that don't look a lo different than the last ones. I'm just happy to see it coming together, Sort of wish I had co2 for a test though


Gray

[DFI pit bull]

Nice to see you are building again Gray.

[sdumper]

House this puppy coming along?

[Gray Mole]

House this puppy coming along?

Well unfortunately she's on hold pending the arrival of Ethylene. I'm not so paitently waiting

I got word back that my application was approved at the supplier which is pretty awesome, since they supply R23, R14, and any and all other gasses I may need in the future. Very cool.

But the small bottle of Ethylene they didn't stock so I had to wait for a shipment from out east. That's a week to 3 and I expect it'll be closer to 3. Not too long though, and as soon as it's here I'll be giving it a real run.

The oversize condensor and airflow should make all the difference I hope. Having a consistent and low condensing temperature makes it so much easier to tune.

I'm finishing up another unit at the moment, should have everything wired by tomorrow and I'll post that up. Dual condensors with independent air intake, small SLHX tube setup. Working at ambient for condensing temp which is great, though I have to cut some air exhaust in the case sides. Thing absolutely eats load though. The 260w dummy runs 6psi low. I did a blowtorch torture test up to 16psi low, and it ran -24 at the back of the evap. Wish I could know what load that is, but I bet on 450w. Pretty cool to see in person but I don't know about posting pics. Last thing you need is a bunch of people playing copycat and accidentally having an evap bursting on them.

So yeah, another week, maybe 2 and I'll be back on the cascade. Everything's mostly insulated though I need to chop the HX insulation down a little to make sure the panels will go on. Just used a box and filled with foam to be wrapped in armaflex tape. I can grind it to a shape that works before I wrap it so it's all good

Gray

[sdumper]

Sounds good!!

[Gray Mole]

Well I can finally dredge up this thread, I got the call today and just went to pick up the Ethylene I ordered


It's got an odd fitting on it, and none of the regulator adapters I have here fit. They're looking to see if they have any in stock but it's here so I can soon get back to it

Just did a quick check and the first stage is still charged and ready, so no leaks, and there's still 250psi of nitrogen in the 2nd stage, so leak free and ready for some testing right away.

I just called and there's one guy that can get the adapter for my regulator, but it'll be tomorrow before it's there. No biggie, I'm going to finish up another one first since it's on the bench and then look at that.

Finally I can get back to the fun stuff though, single stage is good but the -100c stuff us pretty cool too.


Gray

[Gray Mole]

Couple of preliminary results




So she's running nice

Still loads of work to do though, tons of insulating, running a full set of probes, etc.

Good to see that -100 again though

Gray

[Fhqwhgads6680]

Man, nice cascade Gray!

Gotta love the Hyrdocarbons they make such excellent refrigerants

[Gray Mole]

Well I'm getting pretty close to done now

The insulating is all there, found a basic HP cutoff switch to throw one for 375psi (highest I could find in the range I was after) and I have a probe on the HX now too, so it's all more or less there, waiting for final wiring.




MAN it's tight in there! I had to shave the HX insulation down just a hair to fit, since the foam expanded the cardboard 'form' I made. I usually use foam tape for the wrap afterwards, but I don't have the 1.5mm to spare so the black duct tape is fine. Not really a big difference, I didn't need any more insulating, just the tape's not as pretty but whatever. It's sealed and the insulation is very good. Wish I could find non-expanding insulating foam.



When I finalised the charge and took off the lines, I gave the second stage a slight boost of gas, so I'm around -107 or so, might get to -110 eventually if I wait long enough but that's not really that big a deal. I'm good to 350+ watts and that's the more important part.

Final tests saw -93 at 350w even with the boost in gas, so the insulating gave a bit, and the extra gas took it away but that's fine with me.

I could get a lot better temps tuning it for 300w, but really I think that to be sure about 6 core load, especially with the temps of a cascade and the extra OC you 'should' get, you'd likely be ramping up to 350w or close. SS temps I think would only see more like 320w or so, but I've been starting to tune them to 350 as well for 6 core prep.

I got that final frame piece in after reworking the HX box, and made up a couple of 'dummy panels' out of styro so I could seal the chamber. The air is pulled through the condensor, into the box, then out the top, so the panels have to be on for the air to cool the condensor. Works very well actually, but means that they've got to be there, so I've been using a cloth 'tarp' to wrap it in tuning so I could access things until it was tuned, then the panels on I can see the result of real airflow, since the cloth wrap isn't that great.

It's great though, the 'guts' are all done, just need to clean up the wiring, mount the capacitors, install the switches, etc.

There's no pressure guages on this one, and in a way I've never really seen a critical need for them. I mean, if it's not working it's easier to diagnose, but most guys using them don't need or often really understand what they mean.

The temperatures, if followed for use, are more of a 'user' necessity. Some might disagree, and the guages do look pretty cool, but if you have temps for use, and pressure safeties for misuse, then the guages aren't what I would call a requirement.

So that as it is, I'm just setting it up with plugs for a K type meter to work with it. I don't have any displays left really to put on it, though I am considering using a Carel controller for the switching of the second stage. The probes will give real accuracy but the controller would be nice so that a person can just switch it on, and it would take care of the second stage. Would make sure someone didn't switch it on before it's ready too. So I probably will do if I can work out the programming on it. I have a couple Carel controllers, and I remember them being pretty odd to program.

So the final results look like the 'no load' temp of around -107, maybe a touch colder. HX temp unloaded around -45.


350w is giving a result of -93c evap, and the HX is pulling up to -32 after a long while on that load.



So I'm pretty happy with that. I'll do another 'full range' of tests on the unit when I have the wiring and panels and stuff done. This was just to give me an idea of what the last insulation job would do, and where I'd stand on final results, from 0w up to 350w. Probably good to closer to 375w with the extra gas, but I'll test that out when it's a lot prettier

Funny, it's not a lot bigger than the Xmas box project, but it's SO heavy. 50+Kg in a pretty compact setup, kind of tricks you when you go to pick it up.

I'm thinking it's gone a lot better than I'd expected, being my first cascade in a long time (been around 4 or 5 years now?) and the first with R1150, so I'm pretty stoked that it's working 100%.

I'm even happier that it's got that high load I was hoping for. I really want to see in the hands of someone with a 6 core CPU to see if I'm close in my thinking of 6 core load. Now that I'll have a good temp/load database off this unit, when it does see a 6 core full load test I'll know what load it's at based on the comparison. Would help everyone I think, if a really clear comparison was available.

If I can get the panels and wiring done over the weekend, might see an update soon


Gray

[Gray Mole]

Had a quick read, and the Carel IR32z I've got here will read to -99c so if I calibrate the second sensor to read around 10c warmer than the actual temp, I can do a full display. The K probe will be there for accurate measurement, but the display would work if a person didn't have a meter or just didn't want to have to hook it up.

So I guess I'll be working on the programming on it. I've dealt with quite a few, but the Carel's are a pretty advanced controller, considering, so I'm sure it'll be 'fun'.

Says it's actually capable of controlling a 3 compressor system with the 2 probes, so would actually work on a 3 stager pretty cool really.



Gray

[Gray Mole]

Oh, in case anyone missed the fine print

Those styrofoam panels are just a temporary thing. Wouldn't be trying to ship it with those on, they 'might' break

I was kind of curious too, about whether they'd be enough to keep it quieter in use. Unfortunately with the condensor fins being a bit wider and pretty much open for noise they don't really do enough to warrant being there under the panels when they go on.

The LG compressor is actually pretty quiet when it's running at 0-5psi but the other compressor, the Toshiba, it's a much louder compressor. I found on the other bencher I built though, that the Toshiba pulled a lot harder on the Low side pressure.

So I'm happy I ended up with that one on the second stage, it's doing a nice job of keeping the load temp pretty low considering it's tuned for closer to 400w instead of the 300 that's pretty standard at the moment.

I'm trying to read through the programming of the Carel controller but it's not easy first thing in the morning they've really overcomplicated things with it, though it is capable of doing WAY more than most controllers I've used before. Nothing like the 'set it and forget it' mentality of the Dixell's and Eliwell's, that's for sure

But it's back to work, I hope. Not too much left on the 'Garden Tractor conversion' I've been doing for my neice for Xmas, so I hope I can focus on this today

Gray

[Gray Mole]

I was opening up the HX box, just enough to figure out why the HX output temp wasn't working, and found out it was the evap probe that wasn't working and not the one measuring condensing temp

so I'm actually at around -32 condensing, which is great I figured the probe that worked was the evap temp, since it's R290 and I didn't expect any great result, as long as it was cold enough and consistent, but a -32c result for the 1150 is actually pretty good, and better than I'd thought. With a -32c evap at the HX, I thought maybe -25 to -28 or so at best.

Knowing it's under -30 I'm a lot happier, especially with it at 350w.

Thought I'd share that, for no particular reason.

I got the basics on the Carel though, looks like while it'll read 2 temps and work 3 outputs well, it won't work the outputs on the individual temps in a way I can make it work.

So I'll have a display for the lower temp, but only be switching the 2nd stage from the 1st stage temp.

Just need a better NTC probe that'll read as low as possible. NTC's aren't great under -50 so I'll see what I can find.

Even something rated to -70 would be better, if it slows down after that and isn't 'correct' it's not really any issue to me, it's only a reference and the K probe will be there for a person to get an accurate read if they want it.

I have a few here, but nothing that's rated very low. I'll have to hunt and see if there is one that'll get closer to the -100 rating, but I don't know. PT100 and PTC1000's are better for that.

Edit: looks like it just won't work for the lower temp, -62c or something like that is what it reads at 0ohms, so that's the absolute limit.

I'll have to see if I can pick up a PTC1000 probe locally and just stick in the second display for the -100 display.

At least I've got it programmed so it should work for the 1-2 stage switching so it's sort of an automated setup. I liked the idea of that.

I know now that if I wanted to be able to work a 3 stager with one of these, it'd have to be the models with PT100, K/J, or the voltage input using a 1v/6v probe setup.

Gray