Geoffrey C. Bell, PE, Lawrence Berkeley National Laboratory- US Dept. of Energy
The data center in LBNL’s Building 50, Room 1275 has a long and interesting history that stretches back several decades. The center originally housed large, air-cooled IBM computers. It was later reconfigured to support LBNLs’ payroll and other miscellaneous computing needs. In 1996, the National Energy Research Scientific Computing Center (NERSC) was located in this center that used water-cooled Cray C-90 computers. In 1999, the Cray computers were replaced with new air-cooled computers. By July of 2007, the data center had two types of datacom equipment: approximately 250kW of high density research computing clusters and approximately 90kW of “back-of-house” IT equipment.
A baseline energy-use assessment, and subsequent energy-efficiency retrofit analyses, began in July 2007. This assessment confirmed a baseline IT load approximate of 330 kW. With a cooling system capacity of 140 tons (nominal), it only just kept the servers cool. However, during the assessment period while some retrofit measures were being installed, the facility operators added approximately 100 kW of IT load. To further complicate matters, the IT staff was contemplating installing an additional 120 kW of IT load in the near future that would bring the total connected IT load to 550 kW.
With chiller capacity “maxed out” and no additional space to locate additional cooling system capacity, installing efficiency measures (EEMs) to increase the center’s effective cooling capacity were the only option for the LBNL staff. Three main EEM upgrades were identified that resulted in reduced energy waste in the data center, effectively increasing the existing system’s cooling capacity as follows:
Retrofit Tune-up Summary
1. Airflow Optimization
2. Wireless temperature sensors
3. Server rear-door heat exchangers