Study: Granular Fan Control Lowers Cooling Energy Costs

Looking to lower cooling costs? A new study highlights how granular control of fans on air handlers can significantly lower cooling costs. A joint study from Digital Realty Trust, Vigilent Corporation, and Lawrence Berkeley National Laboratory (LBNL) resulted in a 66 percent decrease of cooling energy usage in a California data center.

The project focused on replacing constant speed scroll fans with variable speed electronically commutated motor (ECM) fans and deploying the Vigilent Intelligent Energy Management system to control fan speeds and computer room air handler (CRAH) output. The result was a 66 percent decrease in cooling energy usage.

"The goal of the study was to assess whether the fan speed control system was a viable solution for commercial data centers," said Jim Smith, Chief Technology Officer at Digital Realty. "We found that upgrading fans and adding fan speed controls in our data centers allow us to cool them more effectively and efficiently. In addition, the facility's electrical energy usage was reduced, as was the average and peak electric power demand, resulting in a more energy efficient and sustainable data center environment."

The facility used for the study was Digital Realty’s 135,000 square foot data center located in El Segundo. LBNL monitored the overall effort, creating the baseline and result metrics, and acted as project manager for the energy efficiency grant awarded by the California Energy Commission’s PIER Program.

The results of this project, which were presented at the Silicon Valley Leadership's Data Center Summit last fall, puts some numbers on the energy savings potential brought by granular control of fans on air handlers, and the automation of that function. The study makes a case for granular controls, and for the additional investment of installing variable speed drives in CRAH units. Since they used software from Vigilent to automate these controls, it’s also a good advertisement for that company.