Best practices for engineering government buildings: Energy efficiency

Participants:

• Michelle Blake, PEng, Vice President, Industrial Buildings, Stantec, Vancouver, B.C.
• Jeremy Cooan, PE, LEED AP BD+C, Senior Electrical Engineer, Stanley Consultants, Minneapolis
• Michael J. Rossini, PE, Associate, Senior Electrical Engineer, Bala Consulting Engineers, Boston
• Ciarán Smyth, PE, CEng, PMP, Vice President, WSP, New York City
• John Gregory Williams, PE, CEng, Vice President, Harris, Oakland
• Matthew Williamson, PE, Associate Principal, Arup, San Francisco

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What level of performance are you being asked to achieve, such as WELL Building Standards, U.S. Green Building Council LEED certification, net zero energy, Passive House or other guidelines? Describe a project and its goals, identifying the geographic location of the building.

Matthew Williamson: The bus station project is part of the larger Sacramento Valley Station masterplan project that is targeting net zero energy. The masterplan project includes connectivity between light rail, long-distance rail and commercial and residential development in addition to the bus station itself. The goal is to explore the full potential for community-oriented development incorporating net zero energy, net zero water, LEED certification and Living Community challenge.

Michelle Blake: The most common level of performance for maintenance facilities over the past five years has been LEED Silver. However, most recent projects have revised their target to LEED Gold as the additional effort and cost is not significant. Clients are starting to become more interested in WELL Building standards, Passive House, Green Globes and Envision. Sound Transit’s Operations and Maintenance Facility East targeted LEED Silver but will potentially achieve LEED Gold.

Ciarán Smyth: We have seen a big push toward LEED certification at airports within the U.S. and globally. These include LEED certifications at new airports and major additions in New York, San Francisco, Denver, Seattle, Portland, Indianapolis, Boston, Chicago and more. The U.S. Green Building Council has also worked to make LEED more applicable to airports by addressing the unique space types and conditions that you find in airports and major transit hubs. We are also seeing a ton of interest in health and safety in response to COVID-19 and growing interest in renewable energy and demand management solution to support more resilient operations.

What value-add items are you adding these kinds of facilities to make the buildings perform at a higher and more efficient level?

Ciarán Smyth: WSP has developed customized modeling and analytics tools that allow us to optimize the ongoing energy performance of airports and large transit hubs. We have developed a computational design process that provides designers with real-time data during the design process about the impacts and risks of decisions they are evaluating. These tools focus on the relationship between and integration of, building systems to improve resiliency and long-term building performance.

Michelle Blake: Items added to these types of facilities include highly efficient building envelope systems — like integrated exhaust, heat recovery and supply systems — that continuously monitor the air to reduce outdoor air and heating/cooling requirements while maintaining air quality. These facilities may also use rainwater capture for vehicle wash systems and stormwater retention ponds that also provide outdoor green space for wildlife and staff.

What types of renewable or alternative energy systems have you recently specified to provide power? This may include photovoltaics, wind turbines, etc.

Michael J. Rossini: Bala has specified solar PV systems to provide a portion of the electricity for projects as a renewable energy component of the building infrastructure design. PV system design not only requires a proper layout of the panels, but pathways for accessibility to the PV systems and other equipment that may be on the roof. Coordination with the building MEP systems is also important particularly if rooftop HVAC equipment is used. Equipment must be located to avoid shading portions of the PV array when the sun is at lower angles. The location of plumbing vents must also be considered. The location and space for the inverters is also important including space allowance for future expansion of the system which provides added value to the system design.

How has the demand for energy recovery technology influenced the design for these kinds of projects?

Michael J. Rossini: Energy recovery is applied on almost every project. Energy codes now require the application of energy recovery for smaller systems. The push toward lower and lower energy consumption for net zero buildings and buildings in general has demanded that these systems be as efficient as possible. It is no longer acceptable to design an enthalpy wheel heat recovery system that has a 1-inch air pressure drop across the wheel. Rather, systems should be designed for 0.5-inch drop or lower. This will result in lower fan energy consumption and lead to a more efficient energy recovery wheel with lower face velocity.

What unusual systems or features are being requested to make utilities, public works or transportation projects more energy efficient?

Jeremy Cooan: Many of the charging equipment manufacturers are deploying updated software for their chargers to allow for managed charging activities. These updates allow for added flexibility in off-peak charging activities. While this doesn’t necessarily increase the overall energy efficiency, this does help manage the overall load on the electrical grid by adding heavier electrical loads to the system during off-peak hours rather than during on-peak hours.

John Gregory Williams: Our St. Paul, Minn., construction team is working alongside Weston Engineering, on the process piping installation for an innovative wastewater treatment plant in Village of Roberts, Wis, Wastewater Treatment Facility Upgrade. To reduce the problematic high levels of phosphorus contamination, the system uses a patented Advanced Biological Nutrient Recovery System. Modelled after a traditional activated sludge solution, excess nutrients are consumed in photobioreactors, a kind of algae green house, so that carbon dioxide is consumed too. Following filtration, high quality water can be released. Further advantages are no chemical by-products, reducing disposal fees for the client and the opportunity to use excess algae for the production of bio-plastics, an opportunity for a sustainable future where biodegrade plastics can replace those made from fossil fuels.

Ciarán Smyth: Energy use and resilient operations rely on a detailed understanding of how people are using and moving through your facility. Our Smart Buildings team is developing interesting approaches to smart technology integration to completely change the passenger experience within these facilities. When done well, passengers get the information they need and facility managers are able to optimize their procedures based on the actual real-time use of the airport or transit hub.

Michelle Blake: Alternative energy supply such as photovoltaic systems, solar walls, natural ventilation and waste heat capture systems have all been incorporated into our projects.

What types of sustainable features or concerns might you encounter for these buildings that you wouldn’t on other projects? What do government buildings do differently from civilian facilities?

Michelle Blake: Many of these projects lead the way for sustainable features and designs if government funding is contingent upon sustainability initiatives being achieved such as energy efficiency, reduced water consumptions and reduced GHG emissions. Many also consider the life cycle costs of sustainable features with a payback period of 8 to 12 years rather than just focusing on initial capital costs.

Ciarán Smyth: We are seeing a huge focus on increasing resilience and reliability, which changes the calculus for some types of sustainability solutions. More projects are developing and designing around 50+ year climate risk plans that tend to increase the priority of renewable energy systems, battery and thermal storage solutions and very smart building systems.

Matthew Williamson: Government projects tend to look at longer time scales for projects rather than short-term investments, as government buildings are expected to last 50 or more years. They recognize that public funding creates the expectation that projects reflect community values. As such, they are better able to justify sustainable design elements into projects.

What types of renewable or alternative energy systems have you recently specified to provide power? This may include photovoltaics, wind turbines, etc. Describe the challenges and solutions.

Ciarán Smyth: Airports tend to be cautious about installing solar PV system because of potential glare issues and Federal Aviation Administration regulations. We have used a report developed by the National Renewable Energy Lab to evaluate and identify opportunities for solar power and renewable energy. We are currently evaluating solar installations at four airport projects in the U.S.

Matthew Williamson: The primary renewable power system we evaluated for the Sacramento Valley Station bus station was solar PV. The larger masterplan project considered the mandates for solar thermal systems for residential hot water generation, but these systems are not part of the Sacramento Valley Station bus station project.

How has the demand for energy recovery technology influenced the design for these kinds of projects?

Ciarán Smyth: This will depend on the type of energy recovery systems adopted. Energy codes now require more recovery, particularly on large projects, which transportation hubs tend to be. It’s all about the planning. As energy and MEP designers we are required to provide systems that meet and exceed code adopting LEED, WELL, etc. Once we coordinate and collaborate with the architects, structural engineers, owners, etc., at the early stages of projects, the system design inclusive of energy recovery should not prove to be an issue. Once again, proper planning is key.

How have energy recovery products evolved to better assist in designing energy-efficient utilities, public works or transportation projects?

Ciarán Smyth: Energy efficiency products are not specific to one building type, be it a transportation hub or an office building. They have, however, become more efficient over the years and newer technology has also been developed. Each project is different and using one form of energy recovery product may suit one project but not another. Again, energy and MEP designers using should work in close collaboration with architects and clients to determine the best fit for their building

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