So a year or two ago I was inquiring about hvac help, as I was building a diy chiller for my rotovap and other projects. People have been since asking for pics and details and finally got around to it. So here goes. Note; I’m no where near as smart as you guys so I can’t break down cooling power etc.
This set up brings a 55 gallon drum of glycol down to -25c in about 3 hours. Once chilled, I can run my 5l BVV r1005 rotovap non stop, and it never goes under -22c. Roto heat bath is set at 114f. I believe this can probably handle a much bigger load or rotovap, but alas, I’m no smarty. Cool thing is with so much insulation, once I shut things down. This thing barely loses and temp even over a week. I left it unused once for almost 2 weeks, and the temp of the glycol was still in the negatives.
I don’t have a ton of build pics, but the build itself is pretty self explanatory.
Materials-
—Used 30,000 btu window ac- $300
—2 sheets plywood- I had, but pretty cheap
—About 10 bags of that foam insulation that comes as liquid in a bag, you pop a seam, mix the 2 fluids in the bag and it starts turning into foam. Very simple.
—55 gallon plastic drum
—55 gallons of glycol
—cheap submersible pond pump
The build is simple as seen in pics. I simply built a plywood box that can hold the 55 gallon drum, with ample room around it for insulation. I then built a second box/shelf to hood the ac up high.
Here comes the ONLY complicated part. The idea is to submerge the radiator of the ac in the liquid. On a smaller scale you can slowly bend the pipes to get the radiator to sit in a cooler or tub. For this, I found and paid an hvac guy to simply drain the coolant from the ac lines, cut the line attached to the radiator, plumbed a new pipe going into the barrel, and reattached the radiator in a way that it’s submerged inside the barrel. Then he recharged the lines with coolant.
Filled the barrel with glycol, submerged a cheap pond pump in it, and ran 2 vinyl hoses coming out of it for my in and out flow.
That’s about it. My build details probably aren’t the best, but just looking at the pics you can see exactly what I did. As I said the only rough part was having to re-plumb the ac pipe going to the radiator so I can submerge it in the barrel. That cost 200. It’s been great not relying on the piece of shit chiller they give you with “turn key” systems. Any questions feel free to ask! I think for about 500$ (and can probably do cheaper) this was a great solution for my recovery. I kind of want to test it on other things like cooling solvent tanks and stuff.