Top design trends in data centers: sustainability
David Anderson, PE, LEED AP
Senior Mechanical Engineer, Principal
Drew Carré, PE
Senior Electrical Engineer
Terry G. Cleis Jr., PE, LEED AP
Matt Koukl, DCEP-G
Principal Project Manager, Mission Critical Market Leader
Brian Rener, PE, LEED AP
Saahil Tumber, PE, HBDP, LEED AP
CSE: Low power usage effectiveness numbers are frequently requested by data center owners and operators. What strategies have you employed in new data centers?
Carré: We have provided higher efficiency equipment (UPS and transformers) and work with HVAC designers to avoid over-cooling rooms. Transformer and electrical rooms generally can be warmer than other areas without affecting the reliability and life of the equipment.
Koukl: Our recent design of systems using a chiller-less cooling strategy will provide the lowest cost of operation. While we can’t take credit for the location of the facility nor the associated weather, we were able to work with the owner to push the envelope for high-density solutions to leverage a chiller-less cooling system design. Obviously, this solution isn’t applicable in all climates; however, we look to balance the operational objectives with the energy efficiency and climate to result in the most optimal facility design.
CSE: What types of renewable or alternative energy systems have you recently specified to provide power?
Tumber: I have worked on data center projects that used fuel cells as the primary source of power. The solid oxide fuel cells convert natural gas to electricity using an electrochemical process. The projects had unique requirements and fuel cells were selected after an exhaustive review of commercially available energy systems. One of the challenges was getting approval from the authority having jurisdiction and utility provider. They wanted the design team to comply with codes and standards applicable to combustion equipment such as boilers and generators. Fuel cells utilize combustion-free technology and we had to explain the technology and design to AHJ and utility provider to get them on board.
CSE: What are some of the challenges or issues when designing for water use in such facilities?
Anderson: One of our current client/developers was very firm about deploying air-cooled chillers and not water-cooled chillers. Their concern was the amount of water that would have to be stored on-site, should the utility water source be compromised. There was a slight efficiency trade-off for the reliability and redundancy of utility power and generator power being the only utility dependency, but with the advancement in air-cooled chiller technology, the integrated part load values are much improved in the last five years.
Tumber: The water requirements of data centers can be significant, especially for hyperscale projects, which typically rely on evaporative cooling technologies. The requirements can occasionally burden the public infrastructure, especially for small towns. Working with the AHJ and utilities during design can be challenging because they typically cannot keep pace with the project schedule.
In addition, emphasis is being given to water-efficient designs to cope with the increasingly strained water resources. A multipronged approach that takes into account facets such as water storage, equipment, treatment, recycling and energy interdependence has become critical.
CSE: What level of performance are you being asked to achieve, such as WELL Building Standards, LEED certification, net zero energy, Passive House or other guidelines? Describe a project and its goals, identifying the geographic location of the building.
Anderson: LEED certification. The owner is a developer constructing a 32 critical megawatt facility (phase 1), scalable to seven additional 36 critical megawatt buildings on the same site, just outside of Phoenix, in the city of Mesa. This desert project is respecting the scarce natural resource of water, by designing a cooling system with 24 high-efficiency 500-ton (nominal) air-cooled chillers, de-rated for the local environment, in an N+2 configuration. By achieving a LEED certified building, the owner/developer is able to obtain tax breaks for construction from cities interested in developments. This is a significant amount of investment that developers can save to make or break their return on investment. The project is currently in construction and projected to complete in April 2019, still targeting LEED Silver.
Tumber: From a sustainability perspective, a majority of our projects are being designed to achieve LEED certification, with LEED Gold being the preference. Few hyperscale providers are pursuing certifications via the LEED Volume Program. The program streamlines the process for large users and allows them to certify facilities throughout their portfolio. I recently worked on a 68 megawatt data center located in the Midwest, which is on track to achieve LEED Gold certification. From a risk-mitigation perspective, select projects also are being designed in accordance with certification programs such as UL 3223, which increases end-user transparency and provider accountability.