MEMED right here…
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I remember ya’ll too, Im sure theres more of us here as well, good times.
Heres one of my inspirations for a recirculating chiller:Glycol Chiller | 1/5hp - Ss Brewtech
and cheapish pump: https://www.spxflow.com/en/johnson-pump-marine/pd-mp-marine-automotive-circulation-pumps-cm90bl/
I think I might just trial and error for the right evaporator size, and start with a 1/2ton expansion valve.(edit: not sure if the half ton is correct,)
also a good thread from a cpu modding forum on how to covert a window banger into a autocascade low temp chiller, which goes over the autocascade principals and such in a somewhat digestible manner.(note: my browser gave me a security warning for this site for some reason: https://www.xtremesystems.org/forums/showthread.php?144007-Morphing-Air-Conditioner-into-Autocascade-System
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Yo, you guys inspire me. This bitch has been in storage for years! Messed with her a bit tonight and got her working pretty good.
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so the flat-plate goes on the second loop…
thanks @pangea!!
https://www.mandtsystems.com/documents/Alcohol_Cold_Trap.pdf
probably the feds 
www.xtremesystems.org. The certificate is only valid for XtremesysServer.XTREMESYSTEMS.local
nah just a config error…
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You nailed the dx plater exchanger call, @The_Lone_Stiller
I chickened out last year on this project, again. Hoping to get it going for this year.
Check out the CHN series Plate Exchangers. http://s3.supplyhouse.com/product_files/FPN5X12-36-brochure.pdf
Main hold up is still not knowing how to size the expansion valve and evaporator properly and other minor things like the oil charging loading if it doesnt come so already.
Heres a link to the initially posted tecumseh unit for $1300.
CHN half ton plate exchanger - $435(they also have larger sizes)
https://www.hvacbrain.com/FlatPlate-CHN1-2A/
Capilary tube would cost under $50 or higher end expansion valves for more money.
- Filter
- Feed / suction lines
- Fittings
- Mounting and the like
- Refrigerant(and stuff needed to evacuate and charge the system)
= Inexpensive compared to commercial offerings
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I’ve uploaded a great resource for TXV sizing from sporlan. You can also just call them up , ask for an applications engineer, and they’ll size one for you (although honestly i’ve had them undersize me twice now lol so maybe go one side larger).
For very low temp, you face big issues with hunting if you use a mechanical TXV. The off-the-shelf superheat controllers only function down to -60C so that’s a problem as well. You can either mess with getting a mechanical valve to work or write your own logic on something like a Siemens Logo (which is pretty easy honestly).
For ye DIY’ers looking at big compressors for cheap, go get 'em but beware of compression ratios that are too high. Multi-stage will almost certainly be required but it’s not as difficult as it is daunting.
As you mentioned, oil management is a concern for sure, especially with compressors in series. Read up on discharge side oil separators. If you’re building your own skid, you can afford $400 for a spiral separator and a solenoid for oil return.
Overall, great thread everyone!
10-10.pdf (3.2 MB)
Also, there’s a big write up on this thread that would be relevant to picking a random compressor and finding out how much cold you can get out of it:
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Northern Lab/Breakover from icmag here… Hey guys!!!
I messed around with an ice machine and a immersed coil tank way back when:
We were lucky to have a txv to rob off existing equipment. I wish I knew more about refrigeration, I’d be elbow deep in this.
Why use refrigerant to chill a fluid that you’d need to pump around when you could just use the refrigerant directly?
Seems like chillers could be made much smaller and more efficient that way.
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Awesome work @Dannywarbucks! Nice to hear from you. I wish we could all collaborate and make some cool stuff! I’m soooo down.
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Rated plate evaporators are better than coils, 2464 is a 1.5P compressor, I can provide you some info about the expansion valve, condenser etc if you are interested.
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I am very interested!
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2464 is R404, -40C compressor.
We use #2 Spool Danfoss expansion valve or 1.8m of Φ2.5 capillary.
Fill 450~500g R404, depends on room temp and the low temp you need
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Condenser is 7.8 m2.
With regard to the rated plate evaporators, I am trying to get a drawing, will back to you soon
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Wow thanks for posting the design. I was going to build but trying to understand which diameter of capillaries tubing to use was not an easy answer to find.
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I came across this resource the other day for capillary sizing: Capillary Tubing Info | Refrigerative Supply
Ive seen some pretty mean deals on modern expansion valve too.
Thanks @EffisonAndy
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We use 2.5mm capillaries, 1.8m long.
But you have to test the machine to determine the length of the capillary.
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They are too good and too cheap to not use IMO. Other than the issues with hunting at VLT I mentioned they are just better than cap tubes.
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I found the ZZ series from Emerson for VLT. But I just want to figure out -40 with either r404a or r290, as a start.
EEV’s seem pretty advanced, probably overkill for a first timer.
Just doing last minute searching on other comparable condensing units before I order the awa2464.
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EEVs are like an easy button honestly. Very simple PID to control superheat. We use the Sporlan Kelvin II all the time but the temp transducer only works down to -60C. It wouldn’t be so bad except after that it commands the EEV full close and there’s not dry contact to command a compressor stop so yeah, guess what happens. Certainly makes you get your HPC logic down.
Other issue with the Kelvin II is that it’s pretty expensive. TBH it makes more sense to use a Siemens Logo or similar small PLC with a single PID loop and value chart to run the EEV. Next time I do one I’ll throw the program up on here and save everyone a couple hundred bucks.
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