Trends, changes in data center electrical system design

Respondents:

• Bill Kosik, PE, CEM, BEMP, Senior Energy Engineer, DNV, Oak Brook, Illinois
• Matt Koukl, DCEP, Principal, Market Leader Mission Critical, Affiliated Engineers Inc., Madison, Wisconsin
• Kenneth Kutsmeda, PE, LEED AP, Global Technology Leader – Mission Critical, Jacobs, Philadelphia
• Ben Olejniczak, PE, Senior Project Mechanical Engineer, Environmental Systems Design Inc., Chicago
• Brian Rener, PE, LEED AP, Mission Critical Leader, Smith Group, Chicago
• Jonathan Sajdak, PE, Senior Associate/Fire Protection Engineer, Page, Houston

Bill Kosik, PE, CEM, BEMP, Senior Energy Engineer, DNV, Oak Brook, Illinois – Matt Koukl, DCEP, Principal, Market Leader Mission Critical, Affiliated Engineers Inc., Madison, Wisconsin – Kenneth Kutsmeda, PE, LEED AP, Global Technology Leader – Mission Critical, Jacobs, Philadelphia – Ben Olejniczak, PE, Senior Project Mechanical Engineer, Environmental Systems Design Inc., Chicago – Brian Rener, PE, LEED AP, Mission Critical Leader, Smith Group, Chicago – Jonathan Sajdak, PE, Senior Associate/Fire Protection Engineer, Page, Houston

Are there any issues unique to designing electrical/power systems for these types of facilities?

Kenneth Kutsmeda: One of the unique aspects of designing electrical power systems for data centers is balancing redundancy and maintainability with efficiency. Data centers are considered mission critical with most requiring 24/7 operation with no down time. The electrical systems have to be designed with multiple power pathways to allow concurrent maintenance of each piece of equipment without shutting down the data center. Redundant equipment also must be provided to maintain reliability and fault tolerance. Most equipment, like uninterruptible power supply systems operate more efficiently at near full power. Having systems that run less than 50% loaded or not loaded at all can create a challenge when trying to be efficient and save energy.

What types of unusual standby, emergency or backup power systems have you specified for data centers?

Brian Rener: We are seeing more requests for consideration of large-scale (utility grade) battery and alternative fuel back up power supplies particularly with end use data center clients.

Kenneth Kutsmeda: Jacobs designed a hydrogen fuel cell pilot plant for a data center to replace the diesel generator for backup power. Hydrogen fuel cells produce electricity using an electrochemical process similar to a battery, but they do not need to be recharged. Comparable to a generator, the fuel cell will continue to operate as long as there is fuel. The fuel cell works by passing stored hydrogen through the anode and oxygen through the cathode. Hydrogen molecules are split into protons and electrons in the anode. The positive protons move from anode to the cathode through electrolyte. The negative electrons can’t pass though the electrolyte and flow from the anode to the cathode through and external circuit. The protons, electrons and oxygen then recombine in the cathode to produce water and heat. The waste heat was designed to be coupled with a combined heat and power system for heating or cooling applications. The fuel cell uses low pressure tanks of pure green hydrogen. Limited large-scale green hydrogen production, bulk storage and distribution of hydrogen were some of the current barriers.

Cloud Condo 5-megawatt data center building block. Courtesy: Jacobs

What are some key differences in electrical, lighting and power systems you might incorporate in this kind of facility, compared to other projects?

Brian Rener: Medium-voltage (5 to 35 kilovolt) power systems are typical in larger data centers and not seen in other types of non-mission critical facilities. The use of power switchgear, megawatt UPSs, 2 to 3 megawatt generators are also typical and not always seen in other projects.

How does your team work with the architect, owner’s rep and other project team members so the electrical/power systems are flexible and sustainable?

Brian Rener: Fundamentally we believe data centers should be an engineering led design because mechanical, electrical and plumbing systems are typically the most expensive and important systems for these projects. However, in those cases where an architect is leading the project, engineers must be involved very early in space programing and resilience and energy key performance indicators.

Resilient or resiliency is a buzzword when discussing data centers. What are owners requesting to make the building meet resiliency goals? How are you designing data centers to be more resilient?

Brian Rener: Historically resiliency was focused Uptime Institute tier ratings. While still used in many collocation projects, tier ratings are less stringently applied in other types of data centers. Instead, we are hearing more about flooding, severe storms and water availability as resiliency issues. In many ways data center energy efficiency and water usage go hand in hand. With that approach, however, water and access to it becomes critical to ongoing operations. Adding in some air-cooled or other cooling sources, while not as efficient, allows for continued operation with a loss of water. The approach can also reduce the overall size of the water-cooled system, allowing air-cooling to be trim for peak cooling loads.

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