In a controlled experiment, Intel realized a 74% reduction in power consumption using free-air cooling. Two trailers packed with servers, one cooled using traditional chillers and the other using a combination of chillers and outside air with large-particle filtering, were run for 10 months. The free-air trailer was able to use air cooling exclusively 91% of the time. Intel also discovered a significant layer of dust inside the free-air-cooled server, reinforcing the need for effective fine-particle filtration. You'll likely have to change filters frequently, so factor in the cost of cleanable, reusable filters.
Despite significant dust and wide changes in humidity, Intel found no increase in failure rate for the free-air cooled trailer. Extrapolated to a data center consuming 10 megawatts, this translates to nearly $3 million in annual cooling cost savings, along with 76 million fewer gallons of water, which is itself an expensive commodity in some regions.
Radical energy savings method 4: Use data center heat to warm office spaces You can double your energy savings by using data center BTUs to heat office spaces, which is the same thing as saying you'll use relatively cool office air to chill down the data center. In cold climes, you could conceivably get all the heat you need to keep people warm and manage any additional cooling requirements with pure outside air.
Unlike free-air cooling, you may never need your existing heating system again; by definition, when it's warm out you won't require a people-space furnace. And forget worries of chemical contamination from fumes emanating from server room electronics. Modern Restriction of Hazardous Substances (RoHS)-compliant servers have eliminated environmentally unfriendly contaminants -- such as cadmium, lead, mercury, and polybromides -- from their construction.
As with free-air cooling, the only tech you need to pull this off is good old HVAC know-how: fans, ducts, and thermostats. You'll likely find that your data center puts out more than enough therms to replace traditional heating systems. IBM's data center in Uitikon, Switzerland, was able to heat the town pool for free, saving energy equal to that for heating 80 homes. TelecityGroup Paris even uses server waste heat to warm year-around greenhouses for climate change research.
Reconfiguring your furnace system may entail more than a weekend project, but the costs are likely low enough that you can reap savings in a year or less.