Examining government, state, municipal, federal, and military facilities: Sustainable buildings and energy efficiency
Government and military projects are among the toughest challenges an engineer can face. Demanding facility owners, tight budget limitations, safety concerns, and other factors all come into play. Here, engineers with experience in the field offer advice on how to succeed in regards to sustainable buildings and energy efficiency.
- Roger Chang, PE, LEED Fellow, Principal, DLR Group, Washington, D.C.
- Shem Heiple, PE, LEED AP, Associate Principal, Senior Mechanical Engineer, Interface Engineering, Portland, Ore.
- Dalrio Lewis, PE, Project Engineer, RTM Associates, Orlando, Fla.
- Spencer Morgenthau, CPSM, LEED AP, Director of Business Development, Southland Energy, a division of Southland Industries, Sterling, Va.
CSE: What unusual systems or features is the government requesting to make its facilities more efficient?
Morgenthau: Resiliency and energy security have become integral to clients’ efficiency needs. To meet this demand, onsite generation including solar, cogeneration, energy storage, and related technologies are becoming more prominent in our government projects.
CSE: What types of sustainable features or concerns might you encounter on such facilities that you wouldn’t on other projects?
Morgenthau: Under public-private partnerships, energy-savings performance contracts, design-build, and other alternative procurements, the government is often willing to look at full lifecycle value (20+ years) of technology solutions. This long view allows for the adoption of solutions that would be eliminated from first-cost-focused procurements.
Heiple: Eco-diplomacy is an important consideration in overseas government projects. Eco-diplomacy addresses the local societal impacts of the project, considering issues such as energy, deforestation, water shortages, and effects on a location’s unique ecology. Daylighting is typically a desirable feature in the U.S., but it must be considered in context with the location’s culture and climate as it may not be a desirable feature for hot locations with an overabundance of sunshine.
CSE: 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.
Chang: We have evaluated the use of PV and solar thermal hot-water heating systems on all of our major federal government work, to align with the goals of Executive Order 13514. The challenge is that the available roof area and location of buildings in urban locations do not always allow the most efficient production. The concept of district energy systems requires more consideration. Scale-jumping for renewable energy production appears to make the most sense, where the emphasis is on large utility-scale renewable energy production, with individual buildings being designed to a 70% reduction from a 2000-era average building.
Heiple: We have specified PV on many projects, with some systems capable of offsetting up to 30% of the total building energy use. For many developing countries with solar-rich resources and unreliable power utilities, PV is often chosen based on lifecycle cost analysis. It provides additional independence from unreliable power utilities and helps the local community by reducing already overburdened existing infrastructure. Solar thermal systems are a slam dunk for projects in developing countries with good solar resources where natural gas is not available for domestic hot-water heating. Wind turbines are often brought up in early design discussions, but locations with sufficient wind resources are rare and we have yet to be blessed with a project with adequate wind resources.
CSE: What are some of the challenges or issues when designing for water use in such facilities? What types of low-flow or other water-saving strategies have you incorporated?
Chang: We have incorporated HVAC cooling coil condensate-reclamation systems on projects where there is a high dehumidification demand and condensate can be used for cooling tower make-up water. On a recent project, the production estimate was 65% of the building’s potable water use for indoor plumbing fixtures. We have also started to account for the embodied energy associated with the production of potable water.
CSE: How has the demand for energy-recovery technology influenced the design for these kinds of projects?
Chang: Enthalpic core or enthalpy wheel energy-recovery systems are currently required to meet the 50% total energy-recovery effectiveness specified by ASHRAE 90.1. This technology requires close-coupled exhaust and ventilation airstreams, which require early spatial planning for units. An integrated design approach allows consideration of the impacts of these units on mechanical room sizing and placement earlier in the design process. Fan-power limits within the energy code require careful selection of air handling unit components, as well as duct system design.
CSE: High-performance design strategies have been shown to have an impact on the performance of the building and its occupants. What value-add items are you adding to government, state, municipal, federal, and military facilities to make the buildings perform at a higher level?
Chang: A mindset of resiliency impacts how our teams view design decisions. This embodies considerations of extreme climate, long-term system maintainability, cybersecurity, and utility disruptions.
CSE: What level of performance are you being asked to achieve, such as WELL Building Standards, LEED certification, net zero energy, Passive House, or other guidelines? Describe a project and its goals.
Heiple: All the above-mentioned standards except for the Passive House standard have been considered or have been implemented. LEED certification is usually either referenced or required. Currently, net zero energy/water and the 2030 Challenge are the most influential standards/goals.