DOE-2

 

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Overview of DOE-2 Introduction What is DOE-2? Structure of DOE-2 BDL Processor LOADS HVAC ECON Weather Data Library Uses for DOE-2 Energy Conservation Studies Building Design Studies Validation of DOE-2 Documentation Machine Requirements Impacts of DOE-2 Developers

Introduction

The DOE-2 program for building energy use analysis provides the building construction and research communities with an up-to-date, unbiased, well-documented 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.

What Is DOE-2?

DOE-2 is an up-to-date, unbiased computer program that predicts the hourly energy use and energy cost of a building given hourly weather information and a description of the building and its HVAC equipment and utility rate structure. Using DOE-2, designers can determine the choice of building parameters that improve energy efficiency while maintaining thermal comfort and cost-effectiveness. The purpose of DOE-2 is to aid in the analysis of energy usage in buildings; it is not intended to be the sole source of information relied upon for the design of buildings: The judgment and experience of the architect/engineer still remain the most important elements of building design. Structure of DOE-2 The figure shows a flowchart of DOE-2. Basically, DOE-2 has one subprogram for translation of your input (BDL Processor), and four simulation subprograms (LOADS, SYSTEMS, PLANT and ECON). LOADS, SYSTEMS and PLANT are executed in sequence, with the output of LOADS becoming the input of SYSTEMS, etc. The output then becomes the input to ECON. Each of the simulation subprograms also produces printed reports of the results of its calculations.

DOE-2 Flow

The elements of DOE-2 shown in the figure are as follows:

BDL Processor

The Building Description Language (BDL) processor reads the flexibly formatted input data that you supply and translates it into computer recognizable form. It also calculates response factors for the transient heat flow in walls and weighting factors for the thermal response of building spaces.

LOADS

The LOADS simulation subprogram 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. LOADS 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.

HVAC

The SYSTEMS subprogram handles secondary systems; PLANT handles primary systems. SYSTEMS calculates the performance of air-side equipment (fans, coils, and ducts); it corrects the constant-temperature loads calculated by the LOADS subprogram by taking into account outside air requirements, hours of equipment operation, equipment control strategies, and thermostat set points. The output of SYSTEMS is air flow and coil loads. PLANT calculates the behavior of boilers, chillers, cooling towers, storage tanks, etc., in satisfying the secondary systems 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.

ECON

The ECONOMICS subprogram calculates the cost of energy. It can also be used to compare the cost-benefits of different building designs or to calculate savings for retrofits to an existing building.

Weather Data

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.

Library

DOE-2 comes with a library of building input elements, including wall materials, layered wall constructions, and windows.

Uses for DOE-2
Because of the scope and flexibility of its input, DOE-2 can be used in many applications, especially those involving design of the building envelope and HVAC systems, and selection of energy conserving or peak demand reduction alternatives.

      Energy Conservation Studies

Effect of the thickness, order, type of materials, and orientation of exterior walls and roofs;

Effect of thermal storage in walls and floors, and in energy storage tanks coupled to HVAC systems;

Effect of occupant, lighting, and equipment schedules;

Effect of intermittent operation, such as the shutdown of HVAC systems during the night, on weekends, holidays, or for any hour;

Effect of reduction in minimum outside air requirements and the scheduled use of outside air for cooling;

Effect of internal and external shading, tinted and reflective glass, and use of daylighting.

      Building Design Studies

Initial design selection of the basic elements of the building, primary and secondary HVAC systems, and energy source;

During the design stage, evaluating specific design concepts such as system zoning, control strategies, and systems selection;

During construction, evaluating contractor proposals for deviations from the construction plans and specifications;

A base of comparison for monitoring the operation and maintenance of the finished building and systems;

Analysis of existing buildings for cost-effective retrofits.

Validation of DOE-2
DOE-2 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

Documentation
DOE-2.1E has the following manuals:

• The DOE-2.1E Basics Manual is an introduction to DOE-2 for new users.
• The DOE-2.1E Supplement to the DOE-2.1A Reference Manual (parts I and II)
• The DOE-2.1E Sample Run Book.

Machine Requirements
DOE-2 versions are available for most computer platforms and operating systems. Hardware requirements vary, but generally 32 Mb of RAM and 200 Mb of hard disk space is required.

Impacts of DOE-2
Following is a summary of the applications and impacts of the DOE-2 building energy simulation program.

DOE-2 is the most widely-used government-developed program for building energy analysis in the US and 40+ other countries. It is used to achieve energy-efficient, cost-effective building designs. Users report an average 22% reduction in energy use through use of DOE-2. In the U.S., this has led to a savings of approximately $11B in energy costs through 1998 (an estimate approved by the U.S. Government Accounting Office).

Building Energy Efficiency Standards:  Because it is scientifically rigorous and open to inspection, DOE-2 has been chosen to develop state, national, federal, and international building energy efficiency standards, including:

• The ASHRAE-90.1 standard for commercial buildings, which is based on thousands of DOE-2 analyses for different building types and climates. The standard is mandatory for new federal buildings, and has been adopted by many states for non-federal buildings.
• The ASHRAE-90.2 standard for residential buildings, which is based on 10,000 DOE-2 analyses.
• The State of California standard for commercial buildings (Title 24).
• Standards for other countries, such as Hong Kong, Saudi Arabia, Kuwait, Singapore, Malaysia, Philippines, Indonesia, Thailand, Switzerland, Brazil, Canada, Mexico and Australia.

DOE-2 has been used in the design or retrofit of thousands of well-known buildings.

Some examples in the U.S. are: The White House World Trade Center Sears Tower Hirschhorn Museum Boston City Hall New York State Capitol Texas State Capitol Ronald Reagan Library U.S. State Department NREL Laboratory Bank of Boston Pacific Museum of Flight Peachtree Place One Magnificent Mile

Examples in other countries are: National Library (France) New Parliament House (Australia) Berlin Holocaust Center Nestle' Headquarters (Switzerland) U.S. Embassy (Berlin) DOW Europe (Switzerland) Renault Technocenter (France) Citibank Plaza (Hong Kong)

DOE-2 is the basis of books and design guides on energy-efficient buildings. These include:

Small Office Building Design Handbook

Skylight Design Handbook

Foundation Handbook

Energy and Economics: Strategies for Office Building Design Atrium Handbook

PWC Daylighting Manual and Microcomputer Spreadsheet.

DOE-2 is the source of algorithms, calculation techniques, and correlations for many widely-used simplified methods. These include:

ASEAM-2 simplified energy analysis program

ADM-2 simplified energy analysis program

TrakLoad and LoadShaper simplified energy analysis programs

RESEM program for retrofit analysis

EEDO (Energy Economics of Design Options)

Daylighting Nomographs

Energy Nomographs

AAMA-SKY program for skylight design

ENVSTD program for ASHRAE Standard 90.1

PEAR program for residential analysis

RESFEN (Residential Fenestration Performance Design Tool)

COMFEN (Commercial Fenestration Performance Design Tool)

The private sector has adapted DOE-2 by adding interfaces that make the program easier to use. Some examples are these:

ADM-DOE2 CBIP (Canada> Compare-IT CoolTools COMPLY-24 DesiCalc

DOE-Plus DOE2Parm DrawBDL Energy Gauge USA EnergyPro EZ-DOE

FTI/DOE2 Home Energy Saver (LBNL) Home Improvement Tool (LBNL) Perform 2001 PRC-DOE2 PRC-Tools RIUSKA

RESFEN 3.1 VisualDOE 3.1 Visualize-IT

 
DOE-2 has been incorporated in commercial building design software environments such as COMBINE (European Community) and RIUSKA (Finland).
 
DOE-2 results on the energy-efficiency potential of different building types has been incorporated by Pacific Northwest National Laboratory in the U.S. Energy Information Administration's National Energy Modeling System for predicting future energy demand.
 
DOE-2 is used by professional societies and industry groups for research, development, and impact analysis. For example, ASHRAE used DOE-2 for standards development and the Gas Research Institute (GRI) used DOE-2 to assess the energy economics of, and thereby determine future R+D and marketing efforts for new gas technologies, including gas-engine-driven chillers, desiccant cooling systems, direct-fired absorption cooling, and cogeneration.
 
Many utility companies use DOE-2 as a key element in their demand-side management programs to encourage energy-efficiency as an alternative to building new power plants. For example: Northeast Utilities, Pacific Gas & Electric and Southern California Edison offer DOE-2 analysis to architects and engineers as an incentive to designing energy-efficient buildings. The Bonneville Power Authority (BPA) in its Energy Edge program used DOE-2 to show the practicality of buildings that use 30% less energy than its existing standard. Pacific Gas and Electric (PG&E), the largest investor-owned utility in the U.S., used DOE-2 in its ACT2 (Advanced Customer Technology Test) project to select advanced energy efficiency retrofit measures in residential and commercial buildings. Many States use DOE-2 to determine the potential for energy savings. For example, New York State used DOE-2 to show that adoption of cost-effective conservation measures would reduce statewide electricity consumption by 38%.
 
States and the federal government use DOE-2 to forecast the long-range cost and energy savings of building energy efficiency programs.
 
The National Fenestration Council (NFRC) has used DOE-2 to develop window energy efficiency labels.

Because of its accuracy, DOE-2 is used as a reference standard program. Two examples of this are:

1. ASHRAE validated its widely-used simplified energy calculation method (the TC 4.7 bin method) by comparing its results with DOE-2. This comparison also led to improvements to the TC 4.7 method.
2. The California Energy Commission certifies computer programs for use in Title 24 compliance by requiring that they agree with DOE-2 to within a certain percentage on a set of test buildings.

 
DOE-2 is used in 60+ universities in the U.S. for building science research and for teaching.
 
DOE-2 has been used by national labs, universities, and industry for hundreds of studies of products and strategies for energy efficiency and electric demand limiting. Examples include advanced insulating materials, evaporative cooling, low-E windows, switchable glazing, daylighting, desiccant cooling, cogeneration, gas-engine-driven cooling, cool storage, effect of increased ventilation, sizing of thermal energy storage systems, gas heat pumps, thermal bridges, thermal mass, variable exterior solar and IR absorptance, and window performance labeling.
 
DOE-2 has undergone validation by Los Alamos National Laboratory, Lawrence Berkeley National laboratory and universities to show that that the program can accurately predict energy use in real buildings. Such validation gives users confidence that the DOE-2 results are reliable for well-described buildings.

Developers
DOE-2 was developed by Lawrence Berkeley National Laboratory, Hirsch & Associates, Consultants Computation Bureau, Los Alamos National Laboratory, Argonne National Laboratory and University of Paris. Major support was provided by the U.S. Department of Energy; additional support was provided by the Gas Research Institute, Pacific Gas & Electric Company, Southern California Edison Company, Electric Power Research Institute, California Energy Commission and others.