NREL Buildings and Energy Efficiency Program
"Building researchers at NREL support the U.S. Department of Energy's goal to create the technology and knowledge base for cost-effective zero-energy buildings by 2025. A zero energy building produces as much energy on-site as it consumes on an annual basis, primarily through energy efficiency with any small remaining loads met by photovoltaics and other solar energy technologies."
"However, DOE's zero energy buildings goal cannot be met solely through research to improve energy performance of individual building components (e.g., windows, appliances, heating and cooling equipment, lighting). It also requires a revolutionary approach to building design and operation that can achieve 70%-80% reductions in load coupled with careful integration with onsite renewable energy supplies as well as thermal and electrical storage."
"A revolutionary design, in turn, requires a powerful energy simulation tool that supports evaluation of new zero energy building demand-reduction and energy-supply technologies. The simulation tool must also support various decision points throughout the life cycle of building design and operation. These new software tools calculate the behavior of building control systems and the resultant impact on energy use, peak demand, equipment sizing and occupant comfort to provide performance insights that were previously unavailable to the building industry."
"Energy simulation software tools for evaluation of energy efficiency, renewable energy, and sustainability in buildings are being developed by researchers at NREL. The energy analysis tools listed below include energy analysis software used for both residential and commercial energy performance simulation."
"BEopt is a computer program designed to find optimal building designs along the path to zero energy. In addition to an optimization search, BEopt includes: 1) a main input screen that allows the user to select from many predefined options, those to be used in the optimization, 2) an output screen that allows the user to display detailed results for many optimal and near-optimal building designs, and 3) an options library spreadsheet that allows a user to review and modify detailed information on all available options. For more information, read "BEopt: Software for Identifying Optimal Building Designs on the Path to Zero Net Energy." (PDF 476 KB) Download Adobe Reader.
BESTEST "NREL researchers created this method for testing and diagnosing the simulation capabilities of the exterior envelope portions of building energy simulation programs. BESTEST (Building Energy Simulation Test) evaluates design and analysis tools relative to their ability to adequately model the envelope dynamics of buildings. It has been adapted for certifying tools for Home Energy Rating Systems and by other organizations. Three versions of BESTEST are currently available: IEA BESTEST (detailed hourly (or shorter) time-step simulation programs), HERS BESTEST (detailed and simplified programs with an emphasis on modeling houses), and Florida BESTEST (hot-humid climates). For more information, visit the DOE BESTEST Web page."
ENERGY-10 "A software tool developed at NREL for conceptual design focused on making whole-building tradeoffs during early design phases for buildings that are less than 10,000 ft2 floor area, or buildings which can be treated as one or two-zone increments. Energy-10 performs whole-building energy analysis for 8,760 hours/year, including dynamic thermal and daylighting calculations. It's specifically designed to facilitate the evaluation of energy-efficient building features in the very early stages of the design process. For more information, visit the Energy-10 Web page. The software has been licensed to the Sustainable Buildings Industries Council."
Energy Codes and Standards "NREL works with DOE's Building Energy Codes Program to provide a national model for energy codes. The program works with other government agencies, state and local jurisdictions, national code organizations, and industry to promote stronger building energy codes and help states adopt, implement, and enforce those codes. The Program recognizes that energy codes maximize energy efficiency only when they are fully embraced by users and supported through education, implementation, and enforcement. For more information, visit DOE's Energy Codes Web site."
ENERGYPLUS "EnergyPlus is now the primary software tool used for energy performance analysis of commercial buildings by DOE's Building Technologies Program. Developed in 1996 by DOE, EnergyPlus is a new generation building energy simulation program that builds on the most popular features and capabilities of BLAST and DOE-2. EnergyPlus includes innovative simulation capabilities including time steps of less than an hour, modular systems simulation modules that are integrated with a heat balance-based zone simulation, and input and output data structures tailored to facilitate third party interface development. Other planned simulation capabilities include multizone airflow, and electric power simulation including fuel cells and other distributed energy systems. NREL continues to incorporate new modules and capabilities that cover current technologies, systems, and controls as well as develops new capabilities that support standards development and evaluation of low- and zero energy buildings. For more information, visit DOE's EnergyPlus Web site."
EnergyPlus Example File Generator "A program designed by NREL to help EnergyPlus create sample files."
Home Energy Ratings/Energy-Efficient Mortgages "NREL has published numerous research papers on home energy ratings and energy-efficient mortgages."
LCI DATABASE "NREL and its partners created the U.S. Life-Cycle Inventory (LCI) Database to help life-cycle assessment (LCA) experts answer their questions about the environmental impact of materials used in building industry and other industries. The database provides a cradle-to-grave accounting of the energy and material flows into and out of the environment that are associated with producing a material, component, or assembly. It's an online storeroom of data collected on commonly used materials, products, and processes. For more information, visit NREL's LCI Database."
OPTI-PLUS "Building optimization is essential to achieving zero energy buildings. However, building energy simulations are often used for trial-and-error evaluation of "what-if" technology options in building design-a limited search for an optimal solution. With today's computer power, the bottleneck is no longer simulation run time, but rather the human time to handle input and output. Human-driven methods are inefficient; require skills, experience, and time. Computerized optimization has the potential to automate the input and output, evaluate many options, and perform enough simulations to account for the complex interactions among combinations of options. NREL is developing a computerized optimization tool that can manage thousands of EnergyPlus simulations. This energy analysis tool allows researchers to do a large amounts of calculations with supercomputers that tells them how a building will respond to energy consumption for various building design and technology option sets, including cost. At this time, the building optimization software is primarily for use by researchers. However, NREL plans to eventually provide a user interface for public use. For more information, see "Automated Multivariate Optimization Tool for Energy Analysis." (PDF 1.1 MB) Download Adobe Reader.
SUNREL "NREL developed SUNREL to aid in the design of single- or multizone energy-efficient buildings where the loads are dominated by the dynamic interactions between the building's envelope, its environment, and its occupants. SUNREL is especially well suited for passive solar buildings and includes algorithms for Trombe walls, advanced glazings, schedulable window shading, active-charge/passive-discharge thermal storage, and natural ventilation. The program uses an energy balance method to provide true dynamics of mass in the building using time steps of one hour or less. The model representation of the building is a thermal network solved with forward finite differencing among other techniques. In addition, a simple graphical interface aids in creating input and viewing output. It's relatively easy to learn and review precisely what inputs went into each simulation run. SUNREL is an upgrade of SERI-RES, which was released in the early 1980s by the Solar Energy Research Institute (now known as NREL). The program has been used by researchers around the world and is the underlying building physics and mathematics package in TREAT, an award-winning program offered to all New York State energy auditors by the New York State Energy Research and Development Authority (NYSERDA). For more information, visit NREL's SUNREL Web site."
Weather File Generator for Energy Modeling "A weather modeling program was written by NREL for collecting and providing real-time weather data for energy analysis."