Hawkeye Energy Solutions’ proprietary utility metering system, Hawkeye Talon UMS, was installed and customized to collect operating information from multiple sources, including the existing cooling equipment, server power strips and the UPS systems. Hawkeye Talon UMS also collected information from new meters installed on main electrical input power, HVAC air handlers and chilled-water systems. Some of the items the meters helped to uncover include the following:
- Significant fluctuations in cooling energy usage during the day; most data centers have consistent usage during the day.
- On a typical day, about half of the existing 10 CRAH units would be in cooling mode while the other half would be in heating mode (see the room layout above).
- “Hot spots”—locations in which IT equipment draws more power—were located in the data center. Knowing the location of hot spots helped the team determine how to optimize the airflow distribution throughout the data center.
- Actual power use of the UPS system. Comparing this information to the input power helped the team determine the actual operating efficiency.
Step 3: Cooling System Upgrades
The third step in the energy-efficiency plan addressed the data-center cooling systems and controls. Hawkeye Energy Solutions’ engineers used data from the monitoring system to provide an extremely accurate cooling load analysis. The system data showed the actual space’s cooling load was much lower than the existing cooling equipment capacity. These findings resulted in the following changes to the cooling system:
- Upgraded controls were added to rotate three of 10 units into service at any given time, lock out heating and monitor discharge air temperature from the CRAH units into the IT equipment.
- Variable speed drives were added to reduce CRAH fan speed to 60 percent.
- Room temperature and humidity set points were increased to the latest recommendations by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Atlanta.
After these upgrades, the energy use of the CRAH units was reduced by more than 85 percent. Chilled-water use dropped by more than 60 percent. The Data Center Energy Reduction Graph on this page shows the energy savings in real-time using the monitoring system. The data demonstrated to ComEd that the efficiency upgrades were working and also validated the incentive payout.