Commissioning commercial buildings: Electrical, power, and lighting
Ideally, all nonresidential buildings would be commissioned, and the team would start at the onset of the project. Because that’s not always the case, commissioning authorities and experts offer advice on building projects in various stages of commissioning, recommissioning, or retro-commissioning. Professionals discuss electrical and power systems, and lighting.
Mark A. Gelfo, PE, LEED Fellow, GGP, CxA, EMP, Principal/Vice President, TLC Engineering for Architecture, Jacksonville, Fla.
James I. Givens, CxA, EMP, Division Manager, Field Services, RMF Engineering Inc., Baltimore
Jim Huber, CEM, CDSM, CMVP, LEED AP, NEBB CP, President, Complete Commissioning, Annapolis, Md.
Brian Lindstrom, PE, DCEP, National Director of Commissioning, Burns & McDonnell, Kansas City, Mo.
Paul Meyer, PE, CBCP, LEED AP, CEM, GBE, Senior Vice President, WSP, New York City
CSE: Describe some recent electrical/power system challenges you encountered when commissioning a new building.
Meyer: Very often we find that the emergency-power systems fail on the first commissioning test, and sometimes fail twice before the systems work as designed. When you consider that these generators and transfer switches are usually connected to critical and/or life safety systems, it raises doubt in my mind about the installing contractors.
Lindstrom: Fortunately, because of standards like NFPA 70E: Standard for Electrical Safety in the Workplace, we now have practical safeguards for electrical commissioning that also allow productive work. A common challenge when planning and performing commissioning is misapplication of these safeguards, primarily due to a lack of understanding. For instance, an appropriate arc-flash-mitigation strategy is not just wearing Category 4 personal protective equipment for all work. Yet, we frequently hear of strategies like this. To overcome this challenge, we use our own health and safety executives to help plan our work, educate project teams long before gear is energized, and write safe plans of action that complement our test procedures.
CSE: What types of renewable energy systems have you recently commissioned in a nonresidential building? This may include photovoltaics, ground-source heat pumps, etc.
Meyer: We are seeing photovoltaics on warehouses and public schools. Both have extensive roof areas, usually with very little rooftop equipment. We have also commissioned ground-source heat-pump systems as large as 1,200 tons.
Lindstrom: We frequently encounter various fuel cell technologies (hydrogen, methanol, natural gas, etc.), wind turbines, photovoltaic arrays, geothermal heat pumps, and greywater systems in commercial, telecommunication, data center, military, and light industrial environments.
CSE: How do you work with the engineer, owner, and other project team members to make the electrical/power system both flexible and sustainable at the same time?
Huber: The key here is to get the design teams to think more vertically and less horizontally. Designing a robust infrastructure that allows for proper metering of HVAC, lights, and miscellaneous loads is not hard to do and is very cost-effective when done at the building level as opposed to only the tenant level.
CSE: What types of Smart Grid or microgrid capabilities are owners demanding, and how have you served these needs? Are there any unique commissioning issues?
Huber: Demand-control and distributed generation; most buildings now need to integrate their control subsystems, provide more sensors for the subsystems, and provide submetering. Many owners now require the connection of wind, thermal, and solar energy sources into the grid. There are many proprietary building control systems that are unable to communicate and interact with the grid without some gateway or middleware, and this is something that most owners want to avoid.
Meyer: We commissioned a few combined heat and power systems in the last 7 yr, but the number is dropping. There are many unique issues and only qualified CxAs with direct experience should be involved; but low bid/low cost is driving the customers, so many installations are not being used after start-up.
Lindstrom: Smart Grid and microgrid are distinctly different functions, both of which we see being integrated into more facilities. True Smart Grid functionality, with connectivity to the utility, has been limited thus far to demand-response features. We have, however, seen a dramatic increase in the number of intelligent power-distribution systems that can tell facility managers exactly what is happening in their electrical systems so they don’t have to wait for calls from occupants to learn about issues. On the microgrid front, we’ve designed, built, started up, and commissioned several of these advanced microgrids in the past 5 yr and expect this market to continue to grow. We have seen significant and increasing interest, especially for those that integrate renewable power resources such as solar photovoltaics (PV). In commissioning microgrids, one of the greatest challenges is being granted sufficient time operating as a power island to see the system respond to changes in the renewable assets.
CSE: What unique lighting or lighting-control commissioning projects have you completed?
Lindstrom: California Title 24 projects are usually unique due to the daylighting requirements. One especially unique project involved solar tubes with shades that were integrated with the dimming system. One of the scene settings not only dimmed the internal lights, but also closed the shades on the solar tubes.
Meyer: We have commissioned several daylight-harvesting systems.