Lessons Learned from the Labs21 Case Studies
November 11, 2003
Designers interested in building attractive, comfortable, energy-efficient laboratory buildings can now learn more about the most effective techniques, thanks to the Labs21 case studies. Labs21 has compiled numerous design options and energy-efficient systems in the program's published case studies of state-of-the-art labs.
These case studies show how–without compromising safety–actual laboratory buildings are saving 30 percent or more of the energy that similar, less efficient buildings would use. Many are conserving water as well. To date, six case studies have been published on various types of federal, state, and private-sector labs, and two more will be available later in 2003. These case studies are part of a suite of Labs21 tools developed to assist lab designers.
What has been learned from these case studies? First, variable-air-volume (VAV) supply and exhaust systems are a highly effective way to save energy. Almost all the case study buildings have VAV systems. Since ventilation loads are the dominant energy user in labs, VAV systems offer the greatest savings of all the strategies studied. To get an idea of the extent of these savings, note that one fume hood uses as much energy in one year as three typical houses, and lab buildings can contain several hundred fume hoods.
Second, designers should always consider some form of energy- or heat-recovery system. Using these systems helps reduce the size of the heating and cooling equipment needed in a large lab building, thus saving more energy. Heat recovery is used in five of the case study buildings: three labs use heat wheels, one uses heat pipes, and one includes a run-around coil.
The case studies also point out the importance of assessing and understanding plug loads. One of the buildings was designed for plug loads of 6 watts per net square foot; metering indicates that it is using only 2.7 watts per net square foot (peak). Another building designed for 12 watts per net square foot is also using only 2.7, according to the metering data.
One case study building made use of an energy savings performance contract (ESPC) to replace its aging HVAC system. The ESPC contractor was able to reduce annual energy costs by 60 percent and water consumption by 50 percent. The new systems use state-of-the-art digital controls and VAV supply and exhaust. They also include energy recovery on the exhaust air stream, absorption chillers and heaters, and a 200-kilowatt fuel cell.
The case studies also offer various approaches to providing daylighting and access to outdoor views. Three buildings have higher ceilings close to windows; this design allows natural light to reach farther into the space and reduces the amount of energy needed for electric lights.
The case studies also discuss commissioning, which involves making sure that all installed building equipment and systems are in full working order, according to specifications. Building commissioning and periodic recommissioning of energy-efficient equipment are both important to ensure continued savings. In three of the case studies, third-party commissioning is described. One study includes a good discussion of the importance of ongoing recommissioning of the building's systems.
Finally, because the people who work in labs are also key to efficient operations, one Labs21 case study discusses the importance of educating the staff about the building's efficiency measures. By educating the staff, they can be fully aware of the effects of their work habits and practices on energy and water use.
To learn more, review the case studies at http://labs21.lbl.gov/cs.html or please contact Nancy Carlisle at 303 384-7509 and firstname.lastname@example.org or Otto Van Geet at 303 384-7369 and Otto_VanGeet@nrel.gov, both at the National Renewable Energy Laboratory.