Originally Posted by Locked88
Well would obviously need to have duct run from the AC outlet to the PC case and another duct from the PC case run back to the air inlet on the air conditioner itself. Sealing the case and allowing a 5% or so draw so it's not negatively pressurized in the case.
But it seems like the evap would ice up this way?
Its really hard to do. I've experimented with re-circulating the cold air and found that even with a VERY well insulated and conductive case/duct (i.e. insulation around thin Al or Cu metal), you'll reach a steady-state condition at around 6-8 degC. The steady-state condition occurs when your losses (due to efficiency degradation in the evap, limited thermal isolation of the duct and connection areas, etc.) equal any gains you make in the cooling circuit, i.e. heat or cold is escaping as fast as you produce it.
I'm sure there are improvements you can do to drop the re-circulated air temps a couple of degrees more, but by then you're basically already dealing with condensation in your vent/duct and air has its limitations. And yes, going any further your evap might lose some efficiency as some ice might build up on the surface. By then you might as well be cooling a liquid as it capacitates heat better aka a chiller).
The AC unit to drop in-case temps to 8-10 C in parallel with a liquid cooling solution (use of pumps, waterblocks, rads, etc.) is about the next best thing to a fully (oil or derivative) submerged solution where the fluid itself is recirculated through a chiller of some sort, along with the high flow waterblocks for the chips.
So yeah to answer your question: you can go ahead and recirculate to get your temps pretty low, but it won't be as effective as a chiller and you'll have to deal with condensation. With some sloppy recirculating or just a one-pass through the case, you'll get your temps down a lot without any condensation (in most environments), which is pretty nice if you've got any fans/air-cooling going on. With just AC blowing through my case(s) (not recirculating), I'm around 17C in the case at full load, 45C on the crossfire 5800s, and 45C on the 4.2 GHz.
The ductwork will also be heavy and generally ugly. I'm still thinking up ways to mod an acrylic duct with LEDs or something while not sacrificing too much insulation, or incorporating the AC unit into a case mod.Edited by Voksen - 6/22/10 at 9:08pm