Driving data center design: Sustainability, energy efficiency
In the information age, data centers can be the beating heart of not just a building, but an entire global corporation. Energy-efficient data centers are a core topic of discussion.
- Andrew Baxter, PE, Principal/MEP Engineering Director, Page, Austin, Texas
- Brandon Kingsley, PE, CxA, CEM Project Manager, Primary Integration Solutions Inc., Charlotte, N.C.
- Keith Lane, PE, RCDD, NTS, RTPM, LC, LEED AP BD+C, President/Chief Engineer, Lane Coburn & Associates LLC, Seattle
- Dwayne Miller, PE, RCDD, CEO, JBA Consulting Engineers, Hong Kong
CSE: Please share a success story in which you were able to deliver a highly sustainable project to a data center client.
Lane: Data centers take an enormous amount of resources to operate. Energy efficiency of the electrical and mechanical systems is critical. Electrical meters can be used at the service entrance, at the mechanical equipment and at the UPS systems to determine the amount of power used at various locations throughout the data center. On method utilized to determine the efficiency of the data center is PUE. PUE is essentially the amount of total power the data center consumed divided by actual power used by the servers. Older, less efficient data centers have PUEs above 2.0. Some very efficient data centers today can have PUEs in the 1.2 range. There are many design protocols that are used in today's data center that have greatly increased data center efficiency. These protocols include: more efficient UPS systems, outside air economizers, contained hot aisles, higher voltages, improved server efficiency, warmer cold aisle temperatures, more efficient transformers, controls, VFDs, and lighting. We have recently completed a number of data center build-outs for Sabey Data Center Properties in Quincy, Wash. One operating site at about 50% of the design load has seen an annual operating PUE of 1.18. Other fully commissioned Sabey sites in Quincy using fan carts for more accurate testing have measured numbers lower than 1.18. Sabey and the design team are continually striving to provide reliable and efficient data center facilities.
Baxter: The Chicago project noted in the first question achieved LEED Silver certification, and over a 10-year cycle it is anticipated to save upwards of 420 million kWh of electricity and 115-plus million gallons of water, have more than $35 million-plus in operational savings, and have a 250,000-plus tons of CO2 reduction over a traditional data center similar to the one it is replacing.
Kingsley: The idea of a "sustainable data center" may seem contradictory due to the large amount of electricity and water they will use. Many new data centers are being built on greenfield sites due to many factors, including security and the availability and cost of utilities. Typically, the building construction is fairly basic, so sustainability can be a challenge. Nevertheless, energy savings of 20% or more compared to an ASHRAE baseline building are not uncommon; PUEs of 1.5 or lower are not uncommon either, which is a big reduction from just a few years ago. Commissioning of a sustainable data center that is designed for LEED certification requires additional documentation. When an owner chooses to pursue Path 1, Option 2 for the Enhanced Commissioning Credit of LEED v4, in particular, the commissioning agent is also required to develop an energy measurement and verification plan to confirm that the data center is meeting its performance benchmarks or, if not, to identify possible reasons. We have recently completed a measurement and verification plan for a 6 MW co-location data center that is applying for LEED Silver certification.
CSE: What types of renewable energy systems have you recently specified in one of these projects? This may include photovoltaics, geothermal systems, wind turbines, etc.
Kingsley: We have observed that photovoltaic systems are the most common, but usually these can only provide a small percentage of the building power, so designers usually tie them into noncritical systems such as exterior lighting or office space.
Baxter: At this time we have not had any of our projects incorporate a renewable energy system directly into the design. We have investigated the use of photovoltaics, but to date, for one reason or another, they have not been implemented into the final project. As an alternative to including these in the design of their facilities, we have had several owners sign green power contracts with their utility provider to purchase power generated by renewable energy systems only.