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Software Roundup

Many of the U.S. Department of Energy's Office of Building Technology, State and Community Program (BTS) programs develop software tools to help researchers, designers, architects, engineers, builders, code officials, and others involved in the building life-cycle in evaluating and ranking potential energy-efficiency in new or existing buildings. A few of these tools are featured in this Newsletter. The following list provides information about additional buildings-related energy tools available to the buildings industry developed by Lawrence Berkeley National Laboratory's Environmental Energy Technologies Division.

The energy tools include databases, spreadsheets, component and systems analyses, and whole-building energy performance simulation programs.


ADELINE is an integrated lighting design computer tool developed by an international research team within the framework of the International Energy Agency (IEA) Solar Heating and Cooling Programme Task 12 and 21. It provides architects and engineers with accurate information about the behavior and the performance of indoor lighting systems. Both daylight and electrical lighting problems can be solved, in simple rooms or the complex spaces.

ADELINE produces innovative and reliable lighting design results by processing a variety of data (including: geometric, photometric, climatic, optic and human response) to perform light simulations and to produce comprehensive numeric and graphic information. ADELINE is available for purchase from LBNL at $450.00 per site license.


COMIS (Conjunction Of Multizone Infiltration Specialists) models the air flow and contaminant distributions in buildings. The program can simulate several key components influencing air flow: cracks, ducts, duct fittings, fans, flow controllers, vertical large openings (windows, doors, or both), kitchen hoods, passive stacks, and "user-defined components."

COMIS allows the user to define schedules describing changes in the indoor temperature distribution, fan operation, pollutant concentration in the zones, pollutant sources and sinks, opening of windows and doors, and the weather data. The flexible time step implemented in COMIS enables the modeling of events independent of the frequency with which the weather data are provided. The COMIS air flow calculation is based on the assumption that indoor air flows reach steady-state at each time step. The contaminant transport is based on a dynamic model and has its own time step, based on the time constant of the most critical zone. The two models are coupled. Results for air flows and contaminant levels are reported in terms of tables by COMIS and in graphical form by some of the user-interfaces.

COMIS was developed in 1988-89 by ten scientists from nine countries, during a twelve-month workshop hosted by the Lawrence Berkeley National Laboratory.


The DOE-2 program for building energy use analysis provides the building construction and research communities with an up-todate, unbiased, well-documented public-domain computer program for building energy analysis. DOE-2 is a portable FORTRAN program that can be used on a large variety of computers, including PC's. Using DOE-2, designers can quickly determine the choice of building parameters which improve energy efficiency while maintaining thermal comfort. A user can provide a simple or increasingly detailed description of a building design or alternative design options and obtain an accurate estimate of the proposed building's energy consumption, interior environmental conditions and energy operation cost.


EnergyPlus is a new-generation building energy simulation program based on DOE-2 and BLAST, with numerous added capabilities. It is being written in Fortran 90 with structured, modular code that is easy to maintain, update, and extend. EnergyPlus' developers are the Simulation Research Group at Berkeley Lab, the Building Systems Laboratory at the University of Illinois, the U.S. Army Construction Engineering Research Laboratory, and the U.S. Department of Energy.

Diagram of GenOpt


GenOpt® is a generic optimization program developed by the Swiss Academy of Engineering Sciences, the Swiss National Science foundation, and the Simulation Research Group at Berkeley Lab. It is designed for minimization of a so-called objective function, such as annual energy use, that is calculated by an external simulation program. GenOpt determines the values of the system parameters that lead to optimal operation. It can identify unknown parameters in a data-fitting process. The software also offers an interface for implementing its own optimization algorithms in its library.

Home Energy Saver

The Home Energy Saver (HES) is designed to help consumers identify the best ways to save energy in their homes and find the resources to make the savings happen. The HES was the first Internet-based tool for calculating energy use in residential buildings. The HES quickly computes a home's energy use on-line. By changing one or more features of the modeled home, users can estimate how much energy and money can be saved and how much pollution prevented by implementing energy-0efficiency improvements. All end uses (heating, cooling, major appliances, lighting, and miscellaneous uses) are included.

Screenshot of the Home Energy Saver web site

Users begin by inputting their ZIP code into the Energy Advisor, which begins their interaction with the Home Energy Saver.

The HES's Energy Advisor calculates energy use and savings opportunities, based on a detailed description of the home provided by the user. Users can begin the process by simply entering their ZIP code and in turn receive instant initial estimated for about 250 locations. By providing more information about the home, the user receives increasingly customized results along with energy-saving upgrade recommendations.


RESEM, the Retrofit Energy Savings Estimation Model, is a PC-based tool designed to allow Department of Energy Institutional Conservation Program (ICP) staff and participants to reliably determine the energy savings directly caused by ICP-supported retrofit measures implemented in a building. RESEM incorporates several innovative techniques into an interactive tool designed to ease completion of this demanding analytical task. For maximum accuracy and validity, energy savings are calculated directly from actual utility data, with sophisticated corrections for weather and use variations between the pre-retrofit and post-retrofit utility data collection periods.


RESFEN is a computer tool that can help consumers and builders pick the most energy-efficient and cost-effective window for a given application. It calculates the heating and cooling energy use and associated costs as well as the peak heating and cooling demand for specific window products. Users define a problem by specifying the house type (single-story or two-story), geographic location, orientation, electricity and gas cost, and building configuration details (such as wall type, floor type, and HVAC systems). Window options are defined by specifying the window's size, shading, and thermal properties: U-factor, solar heat gain coefficient, and air leakage rate. RESFEN calculates the energy and cost implications of the windows compared to insulated walls. The relative energy and cost impacts of two different windows can be compared against each other.


SPARK (Simulation Problem Analysis and Research Kernel) is an equation-based, object-oriented simulation environment for building models of complex systems. It allows you to quickly build models of complex physical processes by connecting calculation objects.

SPARK is available in two versions with different interfaces: WinSPARK and VisualSPARK. Both have graphical user interfaces that simplify building and running SPARK models. WinSPARK runs under Windows 95/98/NT and is available from Ayres Sowell Associates. VisualSPARK runs under Windows 95/98/NT and UNIX and is available for beta testing from Berkeley Lab. SPARK was developed by the Simulation Research Group at Berkeley Lab and Ayres Sowell Associates with support from the Office of Building Technology, State and Community Programs, Office of Building Systems of the U.S. Department of Energy.


SUPERLITE 2.0 is a powerful lighting analysis program designed to accurately predict interior illuminance in complex building spaces due to daylight and electric lighting systems. It enables a user to model interior daylight levels for any sun and sky condition in spaces having windows, skylights or other standard fenestration systems. The principle new feature of Version 2.0 is the capability to calculate electric lighting levels in addition to the daylighting prediction. This allows lighting performance simulation for integrated lighting systems. Daylighting and electric lighting systems can also be modeled separately. The program calculates lighting levels on all interior surfaces, as well as on planes that can be arbitrarily positioned to represent work surfaces or other locations of interest to the user. SUPERLITE 2.0 is intended to be used by researchers and lighting designers, who require detailed analysis of the illuminance distribution in architecturally complex spaces. SUPERLITE continues to be enhanced to address current program limitations.


THERM is a state-of-the-art, Microsoft WindowsTM-based computer program developed at Berkeley Lab for use by building component manufacturers, engineers, educators, students, architects, and others interested in heat transfer. Using THERM, one can model two- dimensional heat-transfer effects in building components such as windows, walls, foundations, roofs, and doors; appliances; and other products where thermal bridges are of concern. THERM's heat-transfer analysis allows evaluation of a product's energy efficiency and local temperature patterns, which may relate directly to problems with condensation, moisture damage, and structural integrity. THERM's two-dimensional conduction heat-transfer analysis is based on the finite-element method, which can model the complicated geometries of building products.


WINDOW 4.1 is a publicly available IBM PC-compatible computer program for calculating total window thermal performance indices (i.e., U-values, solar heat gain coefficients, shading coefficients, and visible transmittances). WINDOW 4.1 provides a versatile heat transfer analysis method consistent with the rating procedure developed by the National Fenestration Rating Council (NFRC). The program can be used to design and develop new products, to assist educators in teaching heat transfer through windows, and to help public officials in developing building energy codes.

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