As data centers grow and energy prices rise, the cost of mechanical cooling becomes an unwieldy operating expense.
If servers and other equipment run at elevated temperatures, green data center cooling strategies emerge that require little or no energy to remove heat. Many new data center builds, especially in remote locations, consider alternative cooling suitability. Greener cooling technologies, however, impose new challenges and risks.
Which green cooling methods meet the needs of every data center?
You can't simply select evaporative cooling for a data center in Miami or use free air cooling in Las Cruces, New Mexico. Green cooling technology will depend on the prevailing environmental conditions at your specific data center location:
- An extremely arid environment will benefit from evaporative cooling.
- A data center location near an ample cold water source could use water economizers.
- A site at higher latitudes might opt for air economizers or free air cooling.
Caveats for green data center adopters
Alternative cooling, and even conventional mechanical cooling, rarely works uniformly across the entire data center space. Some kind of containment will limit the amount of conditioned air required, for a lighter and more effective cooling workload.
Failures at elevated temperatures require a much shorter response time than problems at colder facilities. If a data center operating with Class A3 equipment experiences temperatures above 104 degrees Fahrenheit, it takes prompt detection, alerting and decisive action to avert disastrous system failures. Careful data center monitoring and management should include power, cooling and systems management.
Some organizations cool the data center by ventilating ambient air directly into the facility. Free air offers no humidity control; relative humidity will fall as air cools, so cold air drawn into the data center can be extremely dry. If too dry, the air will cause problems with electrostatic discharge. Too humid, and mold and corrosion threaten health and require maintenance stoppages.
Pollution is the more pernicious problem. Cold outside air brings pollen, dust and a myriad of other contaminants into the facility. These particles clog servers' air inlet filters and coat heat sinks and fan blades, reducing airflow and creating an insulating blanket that keeps the servers hot.
Depending on the location, a data center may allow in sulfur-based and other industrial contaminants that will corrode and damage fine electronic interconnections. In the atmosphere, these materials will eventually trigger premature system faults.
Do not introduce ambient air directly into the facility if contamination is possible. Instead, adopt a heat exchanger style of air economizer. It will circulate the inside air where it can be cooled by outside air, then recirculate the cooled inside air back to the equipment. Heat exchangers take advantage of the available environmental cooling but remain sealed against outside contaminants. The closed system approach also controls humidity better.
This was first published in May 2014