Government facility design: Sustainability
Jody W. Baldwin, LEED AP, CEM
Branch Manager, Mid Atlantic Division
Envise, a wholly owned subsidiary of Southland Industries
Christopher Carter, EIT
Associate/Graduate Electrical Engineer
Mark Chrisman, PE, MS
Vice President/Healthcare Practice Director
Gary Krueger, PE, LEED AP BD+C, CM
Vice President and Executive Director
TLC Engineering Solutions
Joshua Meinig, PE
Senior Mechanical Engineer
Brian Pak, PE, LEED AP, BEMP
Senior Mechanical Engineer, Department Lead
CSE: 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.
Pak: Our firm was recently involved in designing the mechanical, electrical and plumbing systems for a 450,000-square-foot, eight-level, built-to-suit office building in the Washington, D.C., metropolitan area for a classified federal government tenant. The project sustainability requirement and goal was LEED Silver certification. The project team ended up delivering LEED Platinum certification contributed by achieving all 21 LEED points for Optimize Energy Performance Credit (EA Credit 1) on the 21-point scale. The cost premium to go from LEED Silver to Platinum was relatively small for the project and was well within the project’s contingency allowance.
Meinig: Typically, LEED certification. Lately I have seen clients ask that the building be designed to LEED certified level but does not want to pursue the certification.
Krueger: Interest in full LEED v4 Certification (which formerly dominated sustainable criteria) has waned in favor of Green Globes and the Federal Guiding Principles program adopted for Federal Department of Defense projects. Increased interest in net-zero or at least net-zero ready facility design. TLC Engineering Solutions recently completed net-zero municipal building for Orlando and are pursuing the Living Building Challenge (includes net-zero energy and water) for a Health Food/Fitness/Restaurant in Daytona, Florida.
CSE: What unusual systems or features are being requested to make their government, state, municipal, federal, correctional and military projects more energy efficient?
Meinig: Nothing unusual, but I have had numerous projects where natural gas was not available close to the site. These projects have been supplied with large propane tanks for winter design, based on the energy requirements.
CSE: What types of sustainable features or concerns might you encounter for these buildings that you wouldn’t on other projects?
Krueger: Federal projects mandate consideration of geothermal, photovoltaic and solar hot water to be incorporated in project designs if determined to be life cycle cost effective. We tend to use this same approach (or recommendation) for all projects.
Pak: Actually, our design philosophy does not vary significantly between government projects and private commercial projects as long as building type, occupancy profile, load profile and operating schedules are comparable.
The following energy conservation measures are considered and applied on most of our office category projects: low temperature, wide differential air/water systems, air-to-air heat recovery, waterside economizer, series-counterflow chiller arrangement, premium efficiency motors, electronically commutated motors, demand control ventilation, temperature reset control, static pressure reset control, chilled water differential pressure reset control, variable speed fans/pumps, dynamic fan speed on terminal device fans, LED lighting with advanced controls, condensing hot water boilers, low-flow domestic hot water system and robust energy management/control system.
Meinig: A lot of the process building on a wastewater treatment require continuous ventilation per NFPA 820. There are ways to reduce the ventilation rates based on the outside temperature but the spaces still require continuous ventilation in the winter regardless of the temperature. These systems use a tremendous amount of energy. These systems are very difficult to provide with energy recovery type equipment due to the nature of the exhaust air.
CSE: What types of renewable or alternative energy systems have you recently specified to provide power?
Krueger: We have specified PV and wind turbines on multiple projects. PV is considered for all federal projects and several municipalities have expressed interest. Department of Defense Education Activity mandates use of demonstration wind turbines on new school design. General challenge is that typical payback analysis for PV is 15 to 20 years, which cause PV to be considered a less desirable project priority.
Our primary solution is to advocate a net-zero ready approach by designing roof structure for a future array and providing the minimal electrical infrastructure to accommodate a future array. The expectation is that PV costs will continue to drop and that the economics will eventually justify the initial PV investment.
CSE: What are some of the challenges or issues when designing for water use in such facilities?
Krueger: Sustainable design often includes water conservation strategies that are still considered unconventional or unfamiliar to code officials. Rainwater capture including cisterns require maintenance and upkeep, which many owners are not accustomed to. Living Building Challenge requires minimal water use or release, which is often difficult for building departments of local health officials to understand or accept.
CSE: How has the demand for energy recovery technology influenced the design for these kinds of projects?
Pak: Energy recovery system has long been part of our standard design practice using air-to-air enthalpy wheels. If applied correctly in office type buildings, enthalpy wheel energy recovery system can lower the cooling load by 10% to 15% and reduce the chiller, cooling tower, pump, piping and electrical sizes accordingly. Typically, the added cost of energy recovery system is offset by the combined lower cost of chillers, cooling towers, pumps, piping, heating system and electrical system. This is one of rare systems or equipment that yields “zero” payback period, meaning this is something that reduces first cost and saves energy at the same time.
CSE: What value-add items are you adding these kinds of facilities to make the buildings perform at a higher and more efficient level?
Meinig: Instantaneous water heaters are a great example of equipment that can make a building more energy-efficient. They use little to no power when not used compared to storage type water heater.
Baldwin: One area of opportunity will be to find the best way to take full advantage of wind energy generation that exceeds real-time need. At certain cases the excess can be sold to the grid, but in low load conditions or circumstances where the wind energy is not connected to a macro-scale grid, battery storage is not always going to be the safest or least expensive answer.
Thermal storage is not in widespread use but that may just be the opportunity. This can take many forms from ice manufacture and storage to potential energy created by pumped water storage facilities. We maximize the return on investment of sustainability initiatives when we maximize their efficiencies.
Pak: The following energy conservation measures are applied on most of our office category projects: low temperature, wide differential air/water systems, air-to-air heat recovery, waterside economizer, series-counterflow chiller arrangement, premium efficiency motors, electronically commutated motors, demand control ventilation, temperature reset control, static pressure reset control, chilled water differential pressure reset control, variable speed fans/pumps, dynamic fan speed on terminal device fans, LED lighting with advanced controls, condensing hot water boilers, low-flow domestic hot water system and robust energy management/control system.