Tools for Building Designers
Operating residential and commercial buildings in the U.S. costs $326 billion annually. Constructing better, more energy-efficient buildings requires sophisticated computer tools. In the late 1970s, Berkeley Lab led the effort to develop DOE-2, the computer program that has since been the standard in the U.S. and in common use internationally. DOE-2 calculates hourly building energy use and cost from information about the building's construction, climate, operation, utility rate schedule, and heating, ventilating, and air-conditioning systems. Berkeley Lab has recently led the development of a next-generation energy-simulation program for buildings called EnergyPlus.
EnergyPlus Building Energy Software
Released in April 2001, EnergyPlus builds on and extends the popular features and capabilities of both the DOE-2 and BLAST programs (BLAST was a Department of Defense funded whole building energy analysis program). A number of institutions worked with Berkeley Lab in developing EnergyPlus, including the U.S. Army Construction Engineering Research Laboratory, the University of Illinois, Oklahoma State University, the University of Wisconsin, Penn State University, the Florida Solar Energy Center, and GARD Analytics. Since its release, there have been more than a hundred thousand downloads of EnergyPlus as of September 2010. EnergyPlus features many innovative simulation capabilities including multizone airflow, thermal comfort, radiant heating and cooling, moisture absorption/desorption in building materials, photovoltaic systems, green roofs, phase-change material simulation, and integration of modular systems and plant with a heat-balanced loads calculation. EnergyPlus was a winner of the R&D 100 award.
- Download EnergyPlus
- "Berkeley Lab Wins "R&D 100" Awards for EnergyPlus Software"
- Available for licensing: EnergyPlus: Energy Simulation Software for Buildings
DOE-2 Building Energy Software
In 1975 the U.S. Energy Research and Development Administration (ERDA, which later became the Department of Energy) and the California Energy Commission (CEC) agreed that a comprehensive building energy analysis computer program was needed to develop and support energy efficiency standards. In response, Berkeley Lab collaborated with Los Alamos National Laboratory and Argonne National Laboratory to create the Cal-ERDA code, which was followed by DOE-1, and finally by DOE-2.
Berkeley Lab was in charge of overall coordination and development of the basic user interface and simulation code. Argonne wrote the user documentation and Los Alamos added active and passive solar simulation capabilities, and developed the engineering documentation. A private company, Consultants Computation Bureau, assisted in developing the interface (Building Description Language) and with the programming.
Examples of well-known buildings designed or retrofitted for increased energy efficiency using EnergyPlus:
- Freedom Tower, New York City, NY
- California Academy of Sciences, San Franciscos, CA
- San Diego Children's Museum, San Diego, CA
- NOAA Pacific Region Center, Ford Island, Hawaii
- New York Times Headquarters, New York City, NY
- San Francisco Federal Building, San Francisco, CA [design award winner]
- National Museum of New Zealand — Te Papa Tongarewa
- World Trade Center PATH Transportation Hub, New York City, NY
- Los Angeles Federal Courthouse, Los Angeles, CA
- San Diego SuperComputer Center, San Diego, CA
- 740 Bel Air Avenue (the "Green Giant"), Montreal, Canada
A steering committee with representatives from DOE, the California Energy Commission, and industry guided the development effort. With the goal of creating an unbiased and well-documented program, Berkeley Lab scientists based DOE-2 on algorithms developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), a respected industry organization. They also used methods from earlier programs including NASA's Energy Cost Analysis program and Two-Zone, a program developed at Berkeley Lab for residential buildings.
The first version of DOE-2 was released in 1978. DOE-2 simulations have formed the basis for a number of building energy-efficiency standards and design manuals. The national voluntary energy-efficiency standard for commercial buildings, ASHRAE 90.1, is based on thousands of DOE-2 analyses of different building types and climates. ASHRAE-90.1 is mandatory for new federal buildings and has been adopted by many states. DOE-2 was also used to develop ASHRAE-90.2, the voluntary residential energy-efficiency standard.
California's energy-efficiency standard (Title 24) for commercial buildings, considered the most advanced in the U.S., is based on DOE-2. The California Energy Commission estimates that this standard saved California consumers $12 billion in electricity costs through 2002 (in year-2000 dollars), and will save $30 billion through 2015.
DOE-2 has also been used to develop energy standards in Saudi Arabia, Egypt, Kuwait, Vietnam, Singapore, Malaysia, the Philippines, Indonesia, Thailand, Canada, Brazil, Australia, Mexico, and Switzerland. Researchers and government officials are currently using it to develop energy standards for buildings in China.
Architecture and engineering firms throughout the U.S. and other countries use DOE-2 to create energy-efficient and cost-effective building designs. A number of the buildings built using DOE-2 have won energy awards from ASHRAE. Users of the program report that it routinely results in a 10 to 30% reduction in energy use and peak electrical demand compared to energy consumed by buildings for which no DOE-2 simulation was done.
Examples of Well-known Buildings Designed or Retrofitted for Increased Energy Efficiency using DOE-2:
- The White House
- The Pentagon
- U.S. State Department headquarters
- U.S. Embassy in Berlin
- The Monterey Bay Aquarium
- San Francisco Airport
- Intel and American Express corporate headquarters
- Numerous federal courthouses
- Frank Lloyd Wright Museum, Wisconsin
- Sears Tower
- Smithsonian Institution's Hirschhorn Museum
- Boston City Hall
- 4 Times Square
- New York State Capitol
- Texas State Capitol
- Ronald Reagan Library
- National Renewable Energy Laboratory buildings
- Bank of Boston
- Pacific Museum of Flight
- Peachtree Place
- One Magnificent Mile
- National Library (France)
- New Parliament House (Australia)
- Berlin Holocaust Center
- Nestle Headquarters (Switzerland)
- DOW Europe (Switzerland)
- Renault Technocenter (France)
- Citibank Plaza (Hong Kong)
Energy-efficient Design Guides Developed with DOE-2 Assistance:
Other Building Energy Software
Berkeley Lab has developed a range of software to help architects, engineers, and researchers design energy-efficient, comfortable, healthy building environments. Many of these software products are available free or under low-cost licensing agreements.
RESFEN helps consumers and builders pick the most energy-efficient and cost-effective window for an application such as a new home, an addition to an existing home, or a window replacement. The software calculates heating and cooling energy use and associated costs as well as peak heating and cooling demand for specific window products.
WINDOW 5.0 calculates total window thermal performance indices (i.e., U-values, solar heat-gain coefficients, shading coefficients, and visible transmittance). This Berkeley Lab program can be used to design and develop new products, to assist educators in teaching about heat transfer through windows, and to help public officials develop building energy codes.
THERM is a computer program for modeling two-dimensional heat-transfer effects in building components (windows, walls, foundations, roofs, and doors), appliances, and other products where thermal bridges are of concern. THERM's heat-transfer analysis allows the user to evaluate a product's energy efficiency and local temperature patterns, which may relate directly to condensation, moisture damage, and structural integrity problems.
RADIANCE is a highly accurate ray-tracing program that is licensed at no cost for non-commercial use. Architects and engineers use it to predict illumination, visual quality, and appearance of innovative design spaces, and researchers use it to evaluate new lighting and daylighting technologies
GenOpt allows multidimensional optimization of an objective function that is computed by a simulation program. The optimization is done by systematic variation of specified design parameters in order to minimize or maximize the objective function. The main purpose of the optimization tool is to avoid the time-consuming process of determining the best values of design parameters. GenOpt is general in its interface and operating structure. The interface is easy to use, and the program can be coupled to any simulation program (such as SPARK or EnergyPlus) that reads its input from a text file and writes its output to a text file. GenOpt, written entirely in Java, is completely platform independent.
VisualSPARK 2.0 is an equation-based simulation environment with graphical interface that allows the user to build customized models of complex physical processes by connecting calculation objects that represent system components such as walls, fans, heat exchangers, chillers, and ducts. This program is useful for simulation of innovative and complex building systems that are beyond the scope of whole-building programs like DOE-2 and EnergyPlus.
The Design Intent Tool offers a structured approach to documenting design decisions that affect a facility's performance in areas such as energy efficiency. Using this database tool, owners and designers can define a building's intended performance and then monitor and verify that the design intent is being met during each stage of the design process. Additionally, the tool gives commissioning agents, facility operators, and future owners and renovators an understanding of how the building and its subsystems are intended to operate, so interested parties can track and benchmark performance.
The Labs21 Tool Kit supports the design, construction, and operation of high-performance laboratories. The tools in the kit include design guides, case studies, and a performance-rating system.
Cal-ARCH is a web-based tool for benchmarking whole-building energy use in California commercial buildings. Its main data source is CEUS, a population-based survey representing the major utility service areas in California.