FEMP Studies Impacts of New Building Performance Standards on Laboratory Design
August 28, 2007
The Energy Policy Act of 2005 (EPAct 2005) has many energy goals and requirements that affect all federal buildings. This article focuses on Section 109, Federal Building Performance Standards. Section 109 requires new federal buildings to meet American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) Standard 90.1-2004. Section 109 also requires new federal buildings to be designed to achieve energy consumption levels that are at least 30 percent below the levels established in the ASHRAE 90.1-2004, if life cycle cost effective.
The energy performance improvements between ASHRAE 90.1-1989 and 90.1-2004 are significant, and a full description is well beyond the scope of this article. As an example, the lighting power density for an office space is 1.0 per square foot in the 2004 version; it was 1.3 watts per square foot in the 1999 version and 1.8 per square foot in the 1989 version.
ASHRAE standard 90.1-2004 has a new "Informative Appendix G Performance Rating Method" intended for use in rating the energy efficiency of building designs that exceed the minimum requirements. The energy performance must be calculated using simulation programs such as DOE-2, BLAST, or EnergyPlus. The improved performance of a proposed building is calculated using the following formula:
|Baseline Building Performance = Total Baseline Building Energy Costs (including ALL plus loads)|
Proposed Building Performance = Total Baseline Building Energy Costs (including ALL plug loads)
Including all end-use loads (such as receptacle and process loads) is a significant change from previous standards. Including all end-use loads will effect all calculations, but it is especially important for buildings with high process loads such as laboratories. For example it is not unusual to see laboratory buildings designed for process loads of 5 to 15 watts per square foot.
- Variable air volume (VAV) system capable of reducing exhaust air and make-up air volume to individual space by at least 50 percent of design values.
- Direct makeup air supply equal to at least 75 percent of the exhaust rate, heated no warmer than 2° Fahrenheit below room set point, cooled to no lower than 3° Fahrenheit above room set point, no humidification added, and no simultaneous heating and cooling used for dehumidification control. (Note that this option is rarely used in laboratory design.)
- Energy recovery systems to precondition makeup air from fume hood exhaust in accordance with 18.104.22.168 (Exhaust Air Energy Recovery) without using any exception.
The Laboratories for the 21st Century program (Labs21) has published draft Laboratory Modeling Guidelines using ASHRAE 90.1-1999 as well as Guidelines using ASHRAE 90.1-2004. These guidelines clarify and modify some of the requirements in ASHRAE 90.1 in order to make them more applicable to laboratory buildings.
In addition, the Department of Energy's (DOE) Departmental Energy Management Program funded a study at the National Renewable Energy Laboratory (NREL) to determine the impact of the EPAct 2005 building standards on new laboratory designs and major renovations. The recently completed NREL study modeled a laboratory building under ASHRAE 90.1-1999 and 2004 versions. The building incorporates many energy conservation measures (ECMs) beyond the baseline requirements of each standard, including daylighting with lighting controls, energy recovery (lab variable air volume was in the baseline), fan coils for each lab, high efficiency boilers and chillers, office under-floor air distribution, and several other ECMs. The laboratory is designed for a process load of 9 watts per square foot. Compared to the ASHRAE 90.1-1999 baseline, the proposed design had an expected savings of 38 percent (calculated excluding process loads). Compared to the ASHRAE 90.1-2004 baseline, the expected savings are 23 percent (calculated including process loads). Some of the difference is because 90.1-2004 will require more efficient heating, ventilation, and air conditioning equipment and heat recovery in the baseline building, but most of the difference is because process loads are included in the baseline for ASHRAE 90.1-2004.
ASHRAE 90.1-2004 is the energy standard that must be used for all new federal buildings. If the building owner chooses to pursue Leadership in Energy and Environmental Design (LEED™) certification, the latest version, LEED 2.2, uses ASHRAE 90.1-2004. It is a good goal to exceed the requirements of ASHRAE 90.1-2004. However, for buildings with high process or receptacle loads such as laboratory buildings, achieving consumption levels that are at least 30 percent below 90.1-2004 may not be practical or life-cycle cost effective.
For more information about Federal Building Performance Standards under EPAct 2005, please contact Otto Van Geet of the National Renewable Energy Laboratory..