The above post is SPAM.
It's been done a lot! Seen many pics and results of a window AC unit with a duct made of many materials to reduce the size to a 4" dryer duct exhaust hose. You can buy the hose at even Wallmart. Then you connect it directly to the input of a 120mm fan somewhere on the case with a custom ghetto adaptor. You can do great on AC air.
Don't expect CPU temp depending on your CPU to be 15C-20C under load, but you will get lower CPU temps for sure. It can only help these GPU monsters too.
Biggest issue is have the PC on before you turn on the AC, it will help with any issue of condensation. Understand/learn dew points and the nature of condensation. Just find rigs and info where others have done it. If your room is at 95% humidity when you turn the AC on, the interior of the PC should be plenty warm to prevent any condensation. But few houses interior is above 60% humidity with central air, so your okay.
A window AC unit is a LOT louder than a normal PC, and pulls a lot of power. Expect your electric bill to be higher.
Been done tho, kinda neat.