I actually work in a data centre in Northern Norway. The problem with this solution is that it can't be done permanently. Unless you go way, way, way north (or south, I suppose), you still have a reasonably hot summertime and the environmental cooling would therefore only work during 3/4ths of the year. So the solution is to either have downtime for 3 months (not going to happen) or go with traditional cooling (you can't swap cooling methods every year, too much work and too much downtime). For us; most of our servers use a watercooling system that feeds cold water from a local spring, which is then heated up by the servers, and that hot water is then used to warm the air inside the buildings, and the water we use. This way we reduce costs for heating both the buildings themselves and the water we use for coffee and such. It's also essentially free cooling as water is virtually free here, there's only the initial piping and such that costs, there's no bill after that. For the rest of the servers, we use traditional high-airflow server fans, so ventilation still costs a non-zero amount.
