A detailed analysis of all power saving opportunities should be performed to ensure that the total cost of operating the data center is kept to a minimum.
Due to their specialized function (hosting power-hungry IT equipment and 24/7 operations), data center facilities often consume more than 100 times the amount of electricity of a large commercial office space. similar. With such electricity consumption, implementing effective energy conservation measures in data centers can significantly reduce energy consumption and associated utility costs. A thorough and detailed analysis of all power saving opportunities should be performed to ensure that the total cost of operating the data center is minimized.
As the designs and operational standards of energy efficient data centers continue to evolve rapidly within the industry, existing data center operators need guidance on best practices to consider in order to maximize efficiency. energy of their facilities.
To improve the energy efficiency of data centers, a benchmark of current energy efficiency must be determined to measure future performance. Energy Use Efficiency (PUE) is a measure, originally developed by The Green Grid, which is an industry-accepted measure of data center efficiency. To determine the PUE, a facility manager divides the total power consumption of their data center by the power consumption of IT equipment.
Direct monitoring / metering of electrical current and voltage at various critical locations in the data center will provide the data used to calculate the PUE. Since the IT equipment and total power consumption of the facility will vary depending on the power demand of the IT equipment as well as the cooling load due to local weather conditions, the PUE should be calculated at frequent intervals. . The PUE values can then be integrated to provide a measure of the “average” energy performance of the data center over a defined period of time. Changes in energy performance can then be tracked to monitor the impact of implemented energy saving measures.
Opportunities for existing data centers
While industry guidelines and standards identify opportunities to implement energy saving measures in newly constructed data centers or those under design, what measures a data center operator existing can explore to achieve greater energy efficiency of facilities? While this is not an exhaustive list, the opportunities to consider include the following:
1. Install the energy consumption monitoring equipment
Existing data centers may not have the robust power consumption monitoring instrumentation and sensors necessary to comply with ASHRAE standards and to collect metrics to calculate the data center PUE. Installing energy monitoring components and systems to measure the energy efficiency of the data center is critical to effectively implementing all other energy conservation measures.
2. Optimize supply air temperatures
Adjust (increase) HVAC supply air temperatures to create an IT equipment environment compatible with the upper end of the recommended temperature ranges noted in the ASHRAE thermal guidelines for data processing environments. Higher supply air temperatures will increase the efficiency of the compressor if a DX type unit is used for cooling or increase the efficiency of the cooling plant if chilled water air handling units are used. used for cooling.
3. Optimize CRAC controls
Stand-alone computer room air conditioning units (CRACs) used in existing data centers often have individual controls and set points that cause the units to over-run due to the ‘struggle’ between them for temperature settings and humidity. Widening the dead zone for temperature and humidity settings will reduce the tendency for these units to behave in this manner. More sophisticated control scenarios can be considered to provide additional energy savings.
4. Separate the plug and the cold air
Create a hot aisle / cold aisle layout for IT equipment to maximize cold air flow to equipment inlets and removal of hot discharge air from equipment racks. The creation of hot or cold aisles can be achieved by adding partitions or ceilings to eliminate the mixture of hot and cold air.
5. Improve the management of the air pressure under the floor
For data centers with raised floor plenums, ensuring that the raised floor system is properly sealed and unnecessary blockages under the floor are removed will improve energy efficiency. Uncontrolled air leaks from the raised floor can result in insufficient amounts of cooled air reaching IT equipment. Blockages and obstructions under the floor can also cause insufficient cold air flow to the equipment. These conditions require higher HVAC supply air temperatures and additional fan energy to handle equipment cooling loads.
6. Improve the efficiency of the CRAC unit
Energy efficiency improvements of CRAC units, including the use of variable speed control for supply air fans and the use of electronically commutated (EC) motors, are standard features of the new units. CRAC. Upgrading existing CRAC units or replacing older CRAC units with these features will result in energy savings.
7. Improve the efficiency of transformers
For data center installations that contain older power distribution components that are nearing the end of their expected useful life, cost-effective energy savings can be achieved by replacing existing standard efficiency electrical transformers with transformers. high efficiency. In addition to generating lower internal electrical losses, high efficiency transformers produce less waste heat which must be mechanically cooled. At the time of replacement, reconfiguring the installation’s electrical distribution system to reduce the number of transformers required, if possible, can also generate energy savings.
8. Improve lighting efficiency
For installations that are currently lit by fluorescent lighting fixtures, replacing or upgrading LED-type fixtures will result in significant energy savings. Installing improved lighting controls such as occupancy / motion detectors or additional manual controls to allow lights to be turned off when spaces are vacant can also be cost-effective energy saving measures.
Existing data center operators can reduce the total cost of operating their facilities by incorporating one of these energy saving opportunities. The savings and projected costs for each opportunity must be carefully assessed to determine which measures are the most cost-effective, with financial resources allocated accordingly. As with all modernization projects, considerations should include flexibility to adapt to possible future technological changes as well as business operating conditions.
Keith Madigan, PE, BEAP, BCxP, LEED AP (BD + C, O + M) is Vice President and Regional Head of Forensic Engineering and Architecture Practice at JS Held, LLC. His professional experience includes detailed energy assessments of over 150 million square feet of commercial, industrial and government facilities, including data centers, in the United States and the Caribbean.
Box: Resources on energy efficiency in industry
ASHRAE Technical Committee 9.9 – Mission Critical Facilities, Data Centers, Technology Spaces and Electronic Equipment produces, as part of the ASHRAE Datacom series, several regularly updated publications that detail current industry practices on a variety of data center design, operation and maintenance issues. . ASHRAE publications of particular interest to data center operators in energy efficiency include Datacom’s energy efficiency best practices and green advice for data centers.
ASHRAE also produces the 90.4 – Energy Standard for Data Centers, which details the energy efficiency requirements for the design, construction, operation and maintenance of data centers. This standard was developed to be code ready and for adoption by local jurisdictions to establish guidelines for the design and construction of new data center facilities.