Yep, pretty much what several others have said. A good sized fan in the window that sucks out hot air (Preferably near the ceiling as hottest air is there). I have a lower half window that just lets cooler outside air get pulled in due to negative room pressure from the fan. Additional fans move the cooler air around at floor level to direct it at rigs.
https://imgur.com/orUWhfcTemperature settings in afterburner throttle the cards if I get above 72 degrees. Not really an issue that I have seen. I have the rigs set up on metal shelves and the floor level rigs stay several degrees cooler than the next shelf up. If I had to do again I would eliminate the upper level rigs and keep everything floor level.