Sorry about the title, but this chiller is really in response to how many times I see threads with guys going to extreme lengths to build chillers out of TECs.
This is what I think a chiller should look like that cools to sub-ambient temperatures, but above the dewpoint. This chiller has a controller that activates a hot gas bypass valve when the system load is too low and the water will get too cool
What I have here is very simple, it's a Copeland 1/6hp condensing unit, High temp, R-134a, low starting torque. I think maybe this model condensing unit was recently made obsolete by Copeland, so there have been tons of them for sale on ebay. I bought some from ebay, I bought a few from Grainger since they stopped selling condensing units a while back and had these on clearance.
OK, also I'm using all new parts, although some are new old stock.
Sporlan balanced port TXV
Alco Hot Gas Bypass Valve
Alco solenoid valve, 115VAC coil
Two 1/2ton SLHXs for the evaporator
A way cheap Chinese PID controller, that using in on/off mode
I did a lot of work on this concept using just one SLHX, I tried using different size HGBVs, and figuring out the best way to build this. I did a lot of load testing with just one SLHX, before I decided that two is better (worth the added cost and complexity), especially since it will allow for fairly low flow rates, i.e. a current watercooling setup might not need to add an extra pump to deal with the chiller.
I've only done some quick tests with a configuration similar to what's pictured, but so far I can say:
@ 60F water deliver temperature, 2GPM flowrate, the cooling capacity should be ~490 Watts
@70F ~600 Watts
Total Power consumption will be ~300 Watts
The compressor always runs, and the controller and HGBV control capacity so that water temperature remains +/- maybe 2 degrees F to the setting on the controller.
I'm still not sure about a case, so the controller is just sitting on the worktable for now. I also need to make a bracket for the evaporator end of the vibration absorber in the suction line, and insulate, but I think what I've done will be easier to understand without insulation.
Next I'm going to insulate and start testing to get the true performance numbers.
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