How to design government buildings sustainably
In this Q&A with multiple experts, learn how to design energy-efficient systems in government, state, municipal, federal, correctional and military buildings
- Steve C. Davis, PE, electrical discipline lead, LEO A DALY, Atlanta
- Raymond Krick III, PE, CxA, LEED AP, project manager, RMF Engineering Inc., Baltimore
- Allen Poppe, PE, principal mechanical engineer, Stanley Consultants, Muscatine, Iowa
- Andrew Stanton, PE, mechanical engineer | senior associate, DLR Group, Cleveland.
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?
Raymond Krick III: Federal, state and local governments have required LEED certification at the silver level when there is a mandate for green building performance. RMF recently worked on a design-build project for the Delaware Army National Guard Combined Support Maintenance Shop in New Castle where LEED Silver certification was required. The project was registered under the LEED v4 rating system. To achieve certification, throughout the design there was a focus on the MEP systems for efficiency to maximize points in the optimize energy performance credit and for metering so that the energy and utility usage could be quantified.
Andrew Stanton: As part of the P100 standard, LEED Gold is required as the part of all designs.
What unusual systems or features are being requested to make government, state, federal, correctional and military projects more energy efficient?
Andrew Stanton: Photovoltaic generation is something that has been increasingly more sought after in designs as energy standards improve and net zero energy becomes more popular.
What types of sustainable features or concerns might you encounter for these buildings that you wouldn’t on other projects?
Andrew Stanton: The majority of government projects include portfolio guidelines with energy and other resource performance targets. These are often augmented with requirements for energy analysis, at key milestones of projects, including life cycle cost analysis.
What types of renewable or alternative energy systems have you recently specified to provide power?
Raymond Krick III: The most common form of renewable energy systems that RMF specifies to provide power are photovoltaic systems. The main challenge in providing a PV design is finding adequate space to locate enough PV panels to generate a significant amount of power. Typically, these systems are located on the roof, so careful coordination with other disciplines is required since much of the equipment for the building systems is also located at the roof level.
Andrew Stanton: We are seeing a primary emphasis on photovoltaics, due to market acceptance, price competitiveness to grid energy and an increasing interest in net zero energy building targets. For existing facilities, a detailed evaluation of roof compatibility for PV is needed, including weight, mounting and shading considerations. Requirements for walkway access to meet between PV panels will impact layouts.
What are some of the challenges or issues when designing for water use in such facilities?
Andrew Stanton: We are seeing a greater interest in rainwater harvesting systems, due to reduce demand on stormwater systems. These systems incorporate components not typical to most facilities, so early collaboration and buy-in from the building operator is needed, to ensure sufficient longer-term resources for maintenance.
How has the demand for energy recovery technology influenced the design for these kinds of projects?
Raymond Krick III: Due to the requirements in ASHRAE Standard 90.1, there is an increasing demand for energy recovery. The challenge in implementation is designing so that it saves energy. Since energy is often used in the form of fan and pumping power to apply the heat recovery, any losses must be minimized. The consequence of limiting pressure drops and including energy recovery is that the equipment gets physically larger and coordination becomes more challenging.
Andrew Stanton: Model energy codes drive demand for airside energy recovery for a greater number of applications. Due to the larger size of air-handling unit systems with energy recovery, such as enthalpy wheels or enthalpic heat exchangers, early planning is required to ensure sufficient space allocations for both equipment and ductwork systems.
What value-add items are you adding these kinds of facilities to make the buildings perform at a higher and more efficient level?
Raymond Krick III: It is important to design for flexibility to add value to these kinds of facilities. Some clients require spare capacity for the MEP systems. Other means for adding flexibility to the systems have been as simple as adding extra valves and connections in piping systems to minimize future shutdowns and tapping into existing systems.
How have energy recovery products evolved to better assist in designing energy-efficient government, state, federal, correctional and military projects?
Raymond Krick III: Several manufacturers now have hydronic modules that offer optimization of the system and combine components such as the heating and energy recovery coils on the airside. These systems also provide continuous monitoring to provide comprehensive real-time information on the system performance. RMF has implemented several of these systems on federal laboratories that our team designed with great success. Although they have a higher first cost than traditional energy recovery systems, the hydronic modules added value by condensing the systems and by offering greater performance.