Small Phase change build R600a

[DashApple]

Hi All .

This was my first attempt at building a small phase change system and want to share the results

There was no real gain to be made from this on the CPU other than for the building experience : ) .
Specs are -

Secop 30AA 3cc R600a compressor
2.8m 0.8mm Capillary tube .
120mm 13W AC fan and 120x120x50mm condenser .
CPU is a i5 3470 ( around 85 - 90W Load )


The evaporator is a copper plate with 1/4" copper pipe coiled and brazed to it .  Under no load evap is -6C , Low side is 1PSI ( -10C Boiling point on R600a ) , Suction line 6" from compressor is -1 to -2 C so superheat is around 8C under no load .


Loaded 100% the temperatures are -1C to 0C evap and 18C reported by the CPU .


PCB is full coated in varnish on both side around and under the CPU socket , Then filled with silicone grease and lined around it with armaflex insulation ( still need to do some more insulating ) .


Not the best looking but i am happy with the results for a first attempt : ) .

IMG_20190805_132413 by TwirlyWhirly555, on Flickr

[Hydron]

Wow, missed this thread before - looks like quite a fun and successful first build! I'd love to have the knowledge and time to build something like this - I remember reading some very interesting threads years ago (on Xtreme systems or something) about people building multi stage phase change systems, so it seems the rabbit hole goes a bit deeper yet.

[DashApple]

Thanks : ) , There was a few issues to get through but in the end it turned out well .

Xtreme systems was and still is a very good place to go for phase change , there is a massive section full of builds and info threads , alot of what i learned was from there : ) .


Some of the cascade and auto cascades on there are crazy , I too would love to be able to do that but for now the simple single stage is where i will probably stay .

[klugesmith]

Very nice.
Is "Phase change" a buzz word these days, for a way to cool overclocked CPU's?  Does pressurized refrigerant circulate inside heat-sink parts and boil right there?

[Mads Barnkob]

Very nice.
Is "Phase change" a buzz word these days, for a way to cool overclocked CPU's?  Does pressurized refrigerant circulate inside heat-sink parts and boil right there?

Seems to be a buzz word for a vapor compression cycle that is carried out by a refrigerant system: https://www.es.aau.dk/sections-labs/Automation-and-Control/Laboratory+facilities/refrigeration/refrigeration-cycle/

[klugesmith]

This old thread seems like a place to discuss flammable hydrocarbon refrigerants, like R-600a (isobutane) above.
They're getting plenty of use these days in freezer chests for retail stores, since US EPA changed the limit from 57 grams to 150 grams per system. I saw one that says "flammable refrigerant" and another one that says it's got R-290 (pure propane).




Does anyone here know if fuel-gas odorants (mercaptans) are compatible with refrigerant applications?

Forgot to mention: I have successfully used "LP gas" as a freezing bath.  Drew liquid from an inverted 9-kg BBQ tank, with a simple pipe adapter that vented gas while letting the liquid drip into a glass Thermos bottle. Outdoors, of course! Reported at 4hv back then.   
https://4hv.org/e107_plugins/forum/forum_viewtopic.php?p=1&id=180082