Software   RESFEN 3.0| WINDOW 4.1 | THERM 2.0 | DOE-2.1E

RESFEN 3.0

Today's energy-efficient windows can dramatically lower the heating and cooling costs associated with windows while increasing occupant comfort and minimizing window surface condensation problems. However, consumers are often confused about how to pick the most efficient window for their residence. They are typically given window properties such as U-factors or R-values, Solar Heat Gain Coefficients or Shading Coefficients, and air leakage rates. However, the relative importance of these properties depends on the site and building specific conditions. Furthermore, these properties are based on static evaluation conditions that are very different from the real situation the window will be used in. Knowing the energy and associated cost implications of different windows will help consumers and builders make the best decision for their particular application, whether it is a new home, an addition, or a window replacement. 

A computer tool such as RESFEN 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. 

RESFEN 3.0 is a major improvement over previous versions of RESFEN because it performs hourly calculations using a version of the DOE 2.1E energy analysis simulation program. RESFEN is currently being evaluated for possible use as part of an annual energy window rating system being developed by the National Fenestration Rating Council (NFRC). RESFEN supplements NFRC Heating Rating (HR) and Cooling Rating (CR) indices (still under development) which are intended to provide relative guidelines on window energy impacts. The input assumptions are being reviewed and may be refined in future versions to more accurately reflect typical building configurations and operation. In addition, the user interface is being redesigned to be even more user-friendly and easy to use.

System Requirements:

OPERATING SYSTEM: Windows 95[tm] or Windows NT[tm]
CPU TYPE: Pentium (a 133 MHz pentium will take about 40 seconds to perform a simulation), 100% IBM compatible 
MEMORY: At least 16 MB of random access memory (RAM), configured as extended memory. 32 MB of RAM is preferred for optimum operation.
HARD DRIVE: Hard disk drive with at least 10 megabytes of available disk space. 
PRINTER: Printer supported by Windows 95[tm] or Windows NT[tm] (serial, parallel, or shared over a network).
OTHER: Monitor and mouse 


Obtaining RESFEN 3.0
To obtain a copy of RESFEN 3.0 please fax a request to:

RESFEN request

Windows and Daylighting Group, 90-3111
Lawrence Berkeley National Laboratory
Berkeley, CA 94720

FAX: 510-486-4089

RESFEN 3.0 | WINDOW 4.1 | THERM 2.0 | DOE-2.1E

WINDOW 4.1

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.

Program Cabalilities
WINDOW 4.1 offers the following features:

  • An analysis methodology consistent with that developed by the National Fenestration Rating Council for the calculation of total fenestration product U-values and Solar Heat Gain Coefficient;
  • The ability to analyze products made from any combination of glazing layers, gas layers, frames, spacers, and dividers under any environmental conditions and at any tilt;
  • Directly accessible libraries of window system components, (glazing systems, glazing layers, gas fills, frame and divider elements), and environmental conditions;
  • The choice of working in English (IP), or Systeme International (SI) units;
  • Help Screens and a manual;
  • A print feature which generates detailed results for a window, window component, or library;
  • The ability to specify the dimensions and thermal properties of each frame element (header, sills, jamb, mullion) in a window;
  • New heat transfer correlations for common muntins and divided lites (dividers);
  • A link with the FRAME 4 program;
  • A multi-band (wavelength-by-wavelength) spectral model;
  • A Glass Library which can access spectral data files for many common glazing materials; 
  • A night-sky radiative model;
  • A link with the DOE-2.1E building energy analysis program.


Performance Indices and Other Results
For a user-defined fenestration system and user-defined environmental conditions, WINDOW calculates:

  • The U-value, solar heat gain coefficient, shading coefficient, and visible transmittance for the complete window system;
  • The U-value, solar heat gain coefficient, shading coefficient, and visible transmittance for the glazing system (center -of-glass values);
  • The U-values of the frame and divider elements and corresponding edge-of-glass areas (based on generic correlations);
  • The total solar and visible transmittance and reflectances of the glazing system;
  • Color properties, i.e. L*, a*, and b* color coordinates, dominant wavelength, and purity for transmitted and reflected (outdoor) solar radiation;
  • The damage-weighted transmittance of the glazing system between 0.3 and 0.38 microns;
  • The angular dependence of the solar and visible transmittances, solar and visible reflectances, solar absorptance, and solar heat gain coefficient of the glazing system;
  • The percent relative humidity of the inside and outside air for which condensation will occur on the interior and exterior glazing surfaces respectively;
  • The center-of-glass temperature distribution.
System Requirements:
OPERATING SYSTEM: DOS, Windows[tm] 3.1, Windows 95[tm] or Windows NT[tm]
CPU TYPE: IBM-compatible 80386 or higher with a math coprocessor, 100% IBM compatible.
MEMORY: At least 8 MB of random access memory (RAM), configured as extended memory.
HARD DRIVE: Hard disk drive with at least 5 megabytes of available disk space.
PRINTER: Printer supported by DOS, Microsoft Windows 95[tm] or Windows NT[tm] (serial, parallel, or shared over a network).
OTHER: Monitor and mouse 


Obtaining WINDOW 4.1
To obtain a copy of WINDOW 4.1 please fax a request to:

WINDOW 4.1 request

Windows and Daylighting Group, 90-3111
Lawrence Berkeley National Laboratory
Berkeley, CA 94720

FAX: 510-486-4089

RESFEN 3.0 | WINDOW 4.1 | THERM 2.0 | DOE-2.1E

THERM 2.0
Two-Dimensional Building Heat-Transfer Modeling

THERM is a state-of-the-art, Microsoft Windows[tm]-based computer program developed at Lawrence Berkeley National Laboratory (LBNL) for use by building component manufacturers, engineers, educators, students, architects, and others interested in heat transfer. Using THERM, you 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 you to evaluate 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.

THERM is a module of the WINDOW+5 program under development by LBNL. WINDOW+5 is the next generation of the WINDOW software series and is being developed for the Microsoft Windows[tm] operating environment. THERM's results can be used with WINDOW's center-of-glass optical and thermal models to determine total window product U-factors and Solar Heat Gain Coefficients. These values can be used, in turn, with the RESFEN program, which calculates total annual energy requirements in typical residences throughout the United States.

System Requirements:

OPERATING SYSTEM: Windows 95[tm] or Windows NT[tm]
CPU TYPE: IBM-compatible 80486 or higher with a math coprocessor, 100% IBM compatible. A Pentium-class computer is preferable for speed. 
MEMORY: At least 16 MB of random access memory (RAM), configured as extended memory. 32 MB of RAM is preferred for optimum operation.
HARD DRIVE: Hard disk drive with at least 5 megabytes of available disk space. 
PRINTER: Printer supported by Windows 95[tm] or Windows NT[tm] (serial, parallel, or shared over a network).
OTHER: Monitor and mouse 
Obtaining THERM
To obtain a copy of THERM please fax a request to: 
THERM request

Windows and Daylighting Group, 90-3111
Lawrence Berkeley National Laboratory
Berkeley, CA 94720

FAX: 510-486-4089

For technical questions about THERM please e-mail Elizabeth Finlayson: 
[email protected]
RESFEN 3.0 | WINDOW 4.1 | THERM 2.0 | DOE-2.1E

DOE-2.1E

An hourly, whole-building energy analysis program for calculating energy performance and life-cycle cost of operation. Commercial PC versions are available. Request a copy of the latest User News from Kathy Ellington for an up-to-date list.
 
Fax: (510) 486-4089
RESFEN 3.0 | WINDOW 4.1 | THERM 2.0 | DOE-2.1E