Weather data is required to produce an accurate simulation.  The weather data for a location consists of hourly values of outside dry-bulb temperature, wet-bulb temperature, atmospheric pressure, wind speed and direction, cloud cover, and (in some cases) solar radiation. Weather data suitable for use in DOE-2 is produced by running the DOE-2 weather processor on raw weather files provided by the U.S. National Weather Service and other organizations.

Weather data can be found in a number of places on the Internet as follows:

• FTI's Weather File Library - This library is provided free of charge to any FTIDOE or DOE-2 user.  We post all files that are donated to us in this library so we always appreciate you sending us any weather data files that you have. 
  
• National Climatic Data Center - You can purchase data files here.
• Australian Weather Data
  
• Lawrence Berkeley Weather Data information page
  

The Economics module computes the life-cycle costs of various building components and generates investment statistics for economic comparison of alternative projects. The methodology used is similar to that recommended by the U.S. Department of Energy for evaluation of proposed energy conservation projects.

This module is used primarily for cost benefit analysis but can also be used to project the operational costs of a building over the design life of the structure.

The HVAC module consists of two main computational  engines: The Systems module that handles secondary systems and the Plant module that handles primary systems.

The Systems module simulates performance of the secondary HVAC equipment used to control the temperature and humidity of each zone within the building. The Systems module uses the output information from the Loads module and a list of user-defined system characteristics (e.g., air flow rates, thermostat settings, schedules of equipment operation, or temperature setback schedules) to calculate the hour-by-hour energy requirements of the secondary HVAC system. The Systems module calculates thermal loads based on variable temperature conditions for each zone.

The Plant module calculates the behavior of boilers, chillers, cooling towers, storage tanks, etc., in satisfying the secondary system's heating and cooling coil loads. It takes into account the part-load characteristics of the primary equipment in order to calculate the fuel and electrical demands of the building.

The Loads simulation module calculates the sensible and latent components of the hourly heating or cooling load for each user-designated space in the building, assuming that each space is kept at a constant user-specified temperature.  This module is responsive to weather and solar conditions, to schedules of people, lighting and equipment, to infiltration, to heat transfer through walls, roofs, and windows and to the effect of building shades on solar radiation. 

Loads are determined using primarily the algorithms described in "Procedure for Determining Heating and Cooling Loads for Computerizing Energy Calculations, Algorithms for Building Heat Transfer Subroutines," available from the American Society of Heating, Refrigerating, and Air Conditioning Engineers, Inc. (ASHRAE).

The Building Description Language (BDL) is used to describe the structure to the simulation engine. The BDL is an intuitive language developed to describe buildings in terms of the operational and construction components.

The BDL processor sequentially checks each BDL instruction for proper form, syntax, and content. The BDL processor also checks for values that are beyond the expected range for the input variables and assigns a default value if one is not specified.

The BDL processor prepares the input data files for use by the Loads, Systems, Plant, or Economics (LSPE) simulators. Each of the LSPE simulators can run repeatedly, to study the effect of design variations. Superior energy-efficient building design can result in greatly reduced energy consumption and significantly lower life-cycle cost.

FTIDOE models are still built using the BDL rather than an Graphical User Interface (GUI).  This type of model description has been retained because of the incredible flexibilty of the BDL.  Years of experience have taught us that us that using the BDL opens up modeling to the limits of the engineers capabilites and not the GUI designers.  We do proivde an excellent context sensitive editor and extensive on-line documention to make this process as simple as typing a letter once you become familar with BDL.

Some examples of BDL input files are as follows:

• Simple Structure - Box with no windows or internal loads.  This is a progressive example that increase the complexity of the stucture in the same simulation run.  This is an excellent training example.
• Single Family Residence with attached sunspace.
• Small Bar/Lounge
• Medical Office Building
• 31 Story Office Building
  

FTIDOE is commercial version of the DOE-2 software that maintains 100% compatibility with the parent software project.  DOE-2 software has been validated by comparing its results with thermal and energy use measurements on actual buildings and with calculations.  Detailed information on some of the DOE-2 program validation efforts may be found in the following reports (available from the National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161):

• Comparison of DOE-2 with Measurements in the Pala Test Houses. Lawrence Berkeley National Laboratory, Report No. LBL-37979, 1995.
• DOE-2 Verification Project, Phase 1, Final Report. Los Alamos National Laboratory, Report No. LA-10649-MS, 1986.
• DOE-2 Verification Project, Phase 1, Interim Report. Los Alamos National Laboratory, Report No. LA-8295-MS, 1981

And from the Following reports from the Simulation Research Group at Lawrence Berkeley Laboratories.

• A Validation Suite for Fuel-Fired Furnace Models
  This e-mail address is being protected from spam bots, you need JavaScript enabled to view it and This e-mail address is being protected from spam bots, you need JavaScript enabled to view it , CANMET Energy Technology Center, NRC, Ottawa, Canada.
  Proc. Building Simulation 2003, 8th Int'l IBPSA Conference, Eindhoven, Netherlands, August 11-14, 2003.
• Validation Studies of the DOE-2 Building Engery Simulation Program -- Final Report
• Comparison of DOE-2 with Measurements in the PALA Test Houses
• Daylighting Simulation in DOE-2: Theory, Validation and Applications

 Additional validation reports and information can be found here.

The following utilites are available for manipulating weather files.  The utilities are provided as is and are not supported by Finite Technologies.  Please review the tools carefully before using.

Convert a formatted ASCII weather file to packed binary file.

• FMTWTH2.EXE - Complied Binary
• FMTWTH2.F - Source Code (FORTRAN)
• FMTWTH2.BAT - DOS batch file to make it work.

Convert a packed binary weather file to a formatted ASCII file.

• WTHFMT2.EXE - Compiled Binary
• WTHFMT2.F - Source Code (FORTRAN)
• WTHFMT2.BAT - DOS batch file to make it work

Perl script to convert a IWEC formated file to TMY2.