i'm not sure about all of the specific parameters.
sealing the volume seems kind of challenging but doable.
if the secondary radiator for dissipating heat from the glycol to air were oversized, maybe it would work?
seems like using a different architecture might be more cost effective and reliable
if you are still really intent on hacking, these copper tube aluminum radiators are like 100-200 usd for 1-4 square feet of radiator area
efficiency can be defined on many dimensions. i can see this being useful if stuck with a window shaker and wanted to make it quieter and able to set up a secondary radiator somewhere else.
context: I use a midea-U 8000 BTU/hr U-shaped "window shaker" looking unit. it's great and efficient. however, the condenser fan PWM is very annoying. maybe it's the PWM whine of the compressor. I would love to make it quieter, and it's possible to set it up in a non-standard configuration.
if i ever wanted to do this approach, i would probably use epoxy or something to seal the coolant enclosure. hehe. would want to do lots of leak testing.
maybe affix a
labyrinth structure to the faces of the
condenser coil, to force the water/glycol to move sequentially through all the condenser and get lots of heat exchange. maybe have the
water/glycol enter in at where the condenser input is. that's where it's
hottest. i'm not sure if trying to go for serial or parallel fluid flow is better, but my gut says trying to focus on the corner of the condenser coil that's hottest is worth it.
after watching the temperatures on the midea 8000 BTU/hr unit, the air outflow from the condenser coil does not regularly exceed 140 °F / 60 °C
these temperatures are normal to deal with in a PC water cooling setting, so I personally think it's something that could work, but would require extra attention to leak management, and maybe end up being a frustrating and ineffective endeavor.
there is also precedent for other fluids, for example:
good luck !