Mechanical Upgrades in Nashville Reduces O&M Costs

Enabled Energy (EE) was asked to provide an assessment of two data centers in Nashville, TN. Several improvements were recommended to improve their energy efficiency and reduce the overall O&M costs for both data centers.

One of the locations had existing motors on their CRACs that were using a large amount of power. EC fans use significantly less energy than OEM fans which are belt driven from induction motors. The use of EC Fans also eliminates the need for belt maintenance. They are variable speed which allows the airflow to be reduced to what is required to keep the racks within the desired temperature range. A total of 7 units were retrofit with EC fans. EE installed their logic board that interfaces and provides a pathway for the existing BMS controls to modulate the speed of the new EC motors to the desired set point necessary to keep the IT equipment at the optimal temperature.

It was also recommended to retrofit existing Leibert CRAC unit fan motors with variable frequency drives to provide an opportunity for energy savings by reducing fan speed to the upflow CRACs. A total of 9 units were retrofitted between the two facilities.

To increase the efficiency of airflow, CRAC return hoods were installed on all 10 units.

The air distribution systems at both locations were recommissioned to ensure the air supply matched the needs of the IT equipment. The CRACs fans were reduced to an average of 60% speed for optimum energy conservation while providing satisfactory and reliable cooling.

In addition to the project being completed on time and on budget, the client is expected to reduce annual energy use by an estimated total of 54 kW or 478,732 kWh. This equates to an ongoing O&M savings of approximately $43,000 per year across both facilities. The total payback for the combined projects is 3.0 years.

Enabled Energy, Inc. completed both projects over a 2-week period in March 2021. Rosenberg provided the EC Fans and ABB provided the VFDs for these projects.