The winder was a breeze, I punched through the wall to an abandoned 6 floo elevator shaft. I pump the heat into the shaft, then bring in cold air from the shaft (Shaft is not insulated). Beautiful temps all winter.

Now that it's summer, I simply only vent into the shaft, that air is replaced with cool air from the HVAC. The HVAC is set up to create positive pressure in the server room, thus the exhaust of the hot air balances nicely.