WASHINGTON - The U.S. Department of Energy (DOE) and its National Renewable Energy Laboratory (NREL) have released two technical reports that provide recommendations on how to achieve 50 percent energy savings in large office buildings and large hospitals. Conducted by NREL’s Commercial Buildings Group, under the direction of DOE’s Building Technologies Program, DOE said the studies support its goal of significantly improving the energy efficiency of new and existing commercial buildings across the United States.

Technical Support Document: Strategies for 50% Energy Savings in Large Office Buildingsevaluates the potential for new large office buildings to achieve a 50 percent net onsite energy savings compared to a baseline standard (as defined by ANSI/ASHRAE/IESNA Standard 90.1-2004). The report found 50 percent energy savings can be achieved in both low-rise and high-rise office buildings in a broad range of U.S. climates. The analysis was conducted in 16 cities that represented different climate zones, such as hot and humid, hot and dry, marine, cold and humid, and cold and dry. The following energy-efficiency measures helped researchers reach the 50 percent energy-savings target:

• High-efficiency boilers, chillers, air distribution units, and service water heating equipment was installed.

• Lighting power density was reduced in office spaces and occupancy sensors were used in infrequently occupied spaces.

• Plug loads were reduced by purchasing high-efficiency electronic equipment and using special controls that shut off equipment when not in use.

For a copy of the complete report, go to http://www.nrel.gov/docs/fy10osti/49213.pdf.

Large Hospital 50% Energy Savings: Technical Support Documentdetails the technical analysis performed and the resulting design guidance that will enable large hospitals to achieve whole-building energy savings of at least 50 percent over the above standard. The large hospitals report also documents the modeling methods used to demonstrate how the design recommendations will help institutions meet or exceed the 50 percent energy-savings goal. This report found 50 percent energy savings can be achieved in large hospitals across all eight U.S. climate zones. Energy savings range from 50.6 to 61.3 percent, with the smallest savings in humid climates and extremely cold climates. The highest energy savings were achieved in marine climates, with relatively high energy savings achieved in dry climates. In general, for each climate type (humid, marine, and arid), savings were seen to decrease as the climate became progressively colder.

For a copy of the complete report, go to http://www.nrel.gov/docs/fy10osti/47867.pdf.

DOE commissions technical support documents to describe the assumptions, methodologies, and analyses used to achieve certain levels of energy performance. In addition to the new documents, DOE has commissioned documents in the following categories of commercial buildings:

50% Energy Savings- General Merchandise, Grocery Stores, Highway Lodging, Medium Box Retail, Medium Office

30% Energy Savings- Highway Lodging, K–12 Schools, Small Hospitals and Healthcare Facilities, Small Office, Small Retail, Small Warehouse

The technical support documents are available on the NREL website at www.nrel.gov/publications.

In many cases, technical support documents are the basis for Advanced Energy Design Guides (AEDGs), which are how-to guides that show architects, engineers, and building designers how to achieve above-code energy efficient performance for buildings using existing technologies available today. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) works in collaboration with DOE, the American Institute of Architects, the Illuminating Engineering Society of North America, and the U.S. Green Building Council to develop and publish AEDGs.

In addition to the ASHRAE design guides, the results of these studies will be shared with DOE’s Commercial Building Energy Alliances. These alliances are public-private collaborations aimed at developing energy-efficient technologies and practices and sharing the information with commercial building owners and operators around the United States.

For more information, visit the DOE’s Building Technologies Program website at www1.eere.energy.gov/buildings.

Publication date:10/04/2010