How Low Can You Go?

Setting Our Sights on Zero-Energy Buildings

Building designers carry significant responsibility for the future of climate-change emissions in the U.S. Domestically, buildings account for 40% of total energy and 75% of electricity use, and they contribute heavily to the generation of carbon dioxide and black carbon, the two leading drivers of climate change. In response, the building industry is moving toward higher energy performance, as codes become increasingly stringent and more owners opt for net-zero solutions. The Federal Government is providing leadership on this front: Executive Order 13514 and the Energy Independence and Security Act of 2007 mandate that all new federal buildings be designed for net-zero energy by 2020, and must achieve that goal by 2030. 

What Is Zero Energy?

Zero-energy buildings fall under one of the following four definitions:

  • Zero Site Energy: A zero-site-energy building produces at least as much energy as it uses in a year, accounted for at the site. 
  • Zero Source Energy: A zero-source-energy building produces at least as much energy as it uses in a year, accounting for the fossil fuels extracted to provide energy for buildings. 
  • Zero Carbon: A zero-carbon building uses either renewable-only energy sources or offsets its use of fossil fuel energy sources with renewables.
  • Zero Energy Cost: Plainly, these are buildings that realize an annual energy bill of $0 and are capable of producing enough renewable energy to offset utility-provided energy costs, depending on rates and net metering agreements.  

SMMA is embarking on a research project to develop a roadmap for zero-energy buildings in cold climates. We aim to identify specific challenges for military projects to achieve zero-energy performance, and evaluate life-cycle cost impacts to understand potential implications to construction and operational budgets.

Assessing Our Work

Our approach involves studying one of our existing military projects—a 51,000-square-foot, LEED-NC Silver-certified facility, completed in May 2011—and understanding the types of changes necessary to make a building zero-energy, rather than simply “efficient.”

The project we have chosen to study is our Armed Forces Reserve Center training building in White River Junction, Vermont. The actual building design will be treated as the project baseline, and upgrades to the building enclosure and systems will be evaluated to identify a feasible zero-energy design. The first costs of these upgrades will then be assessed, in a life-cycle cost analysis, against the operational energy savings.

Developing a package of net-zero-energy measures will follow these steps:

Establishing an Energy Budget

Estimating potential annual renewable energy generation on the site and establishing a target energy-use intensity (EUI), or energy use per square foot.

Minimizing Heating and Cooling Loads

Minimizing heating and cooling loads by enhancing the building enclosure through additional wall and roof insulation, as well as triple glazing.

Optimizing Lighting

Minimizing lighting-energy use through daylighting, efficient fixtures, controls, and reflective surfaces.

Addressing Plug Loads

Analyzing building equipment use patterns and potential controls to reduce effective equipment power density.

Maximizing Systems Efficiency

Evaluating alternate HVAC systems, including options that decouple thermal loads from ventilation.

Modeling Early and Often

Using energy modeling to evaluate packages of energy-efficiency measures that can meet the target EUI.  

Evaluating Cost

Evaluating the additional first cost and maintenance costs with operational savings over a 40-year life-cycle cost analysis.  

Although we are conducting this research specifically for White River Junction, the lessons learned can inform the design of any cold-climate building. This undertaking will prove critical in helping SMMA adhere to its AIA 2030 Commitment goals.

AIA 2030: Making a Commitment to the Future

Keep reading if you're interested in learning more about the AIA 2030 Commitment.

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