# Presentation: 752790

## EnergyPlus:DOE’s Next Generation Simulation Program

- Drury B. Crawley
- U S Department of Energy

## EnergyPlus

- Fully integrated building, envelope, HVAC and renewables simulation program
- Originally based on BLAST and DOE-2.1E, now far exceeds their capabilities
- One of the most robust simulation tools available in the world today
- Enables integrated energy performance analysis of low-energy technologies in commercial and residential buildings including on-site generation and renewable energy sources
- Interfaces available from private sector developers as well as web interface
- Version 1.0 Launched April 2001
- Windows 2000/XP, Linux & Mac

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## EnergyPlus Team

- U.S. Department of Energy
- Lawrence Berkeley National Laboratory
- National Renewable Energy Laboratory
- Oak Ridge National Laboratory
- Florida Solar Energy Center
- GARD Analytics, IL
- DHL Consulting, CO
- University of Illinois at Urbana-Champaign
- COP Associates, MN
- Oklahoma State University

## Loads Features

- Time dependent conduction
- Conduction through building surfaces calculated with conduction transfer functions
- Heat storage and time lags
- Sub-hourly timesteps
- Default is four 15-minute timesteps per hour
- Room air models
- Default is “well-stirred” with uniform temperature
- Other options:  displacement vent, cross vent, UFAD, Mundt, user-defined temperature patterns

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## HVAC Features

- Flexible specification of HVAC equipment
- Components arranged on loops
- Not limited to predefined system configurations
- More than one system may serve a zone
- e.g. Dedicated outside air system plus fan coil units

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## Integrated Simulation Manager

- Simultaneous simulation of loads, systems and plant
- Air and water loops solved iteratively each time step
- Provides tighter coupling between the air- and water-side of the system and plant
- Allows capacity limits to be modeled more realistically
- Loads “not met” result in zone temperature and humidity changes

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## Current Version Status

- Current version 2.2.0.023, April 2008
- Dual-setpoint humidistat
- Enhanced economizer controls
- Greater flexibility in specifying internal gains (i.e., people, lights, equipment) and ventilation/infiltration
- Microturbine electric generator model, and
- Lots of new HVAC capabilities and data sets.
- Twice yearly updates—April and October
- Upcoming features (October 2008 and beyond):
- VRV
- Controls – EMS & Strategies
- Lots more low-energy building, HVAC and other technologies

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## Testing and Validation

- Regression test suite run for every build
- Hundreds of examples and test cases checked to ensure no changes in results (bugs) are introduced
- Standardized test suites run for every major build and before release
- ASHRAE
- Standard 140 (envelope loads BESTEST)
- 1052-RP (building fabric analytical load calculations)
- IEA BESTEST
- HVAC E100/200 (unitary space cooling equipment)
- HVAC E300/400/500 (unitary cooling with outside air)
- HVAC Furnace (fuel-fired furnaces)
- Ground-Coupling (heat transfer from slab on grade)
- Updated reports available on the EnergyPlus web site soon after each release

## ASHRAE Standard 140 Test Results

## Private Sector User Interfaces        

- Private Sector User Interfaces

**EP-Quick**

**BEE *****(Chinese)***
**TREAT Plus**
**COMFEN**
**ESP-r **
**EnergyGauge**
**EPlusInterface**
**HVAC Energy**
**SolarShoeBox**
**xEsoView**
**others, ....**

- PV modeling by EnergyPlus

**EFEN**

**ECOTECT**

## CADD to EnergyPlus

- Translate CADD to EnergyPlus
- International Alliance for Interoperability
- Any CADD software that supports interoperability.
- Available since 2001
- Limited  to what CADD tools export–typically only geometry
- Green Building Studio (now part of AutoDesk)
- Web-based conversion of  major CADD formats to energy simulation inputs
- Limited coverage
- Requires users to create their CADD drawings  in structured way (may not follow designer regular methods)
- Direct from CADD to EnergyPlus
- Graphisoft adding direct export from ArchiCAD to EnergyPlus, later in 2008
- Bentley recently purchased HEVACOMP and investigating direct link from Microstation
- Interoperability is a key to getting energy simulation mainstream.  Other key drivers are zero-energy buildings and green building rating systems.

## Web Interface

- Web interface for simple buildings
- Select:
- Location
- Standard (currently 90.1-1999, 2001, 2004, 2007 and AEDGs)
- Building types
- Floor area
- Number of floors
- Internal loads
- Shape/Aspect ratios
- Glazing percentage
- HVAC equipment/systems

## SketchUp

- Intuitive, easy-to-use 3-D drawing software
- Available from Google as free or pro versions
- Popular among architects
- Powerful API using Ruby programming language for plugins

## Energy Design Plugin

- Create/Edit EnergyPlus Input Files
- Run EnergyPlus and view results
- Automatically create building models

- Adds EnergyPlus functionality
- to the SketchUp 3-D environment

## Energy Design Plugin

- Developed by NREL
- Still in development
- Beta version released early April – now more than 2000 downloads
- Available for free at_ __[www.energyplus.gov](http://www.energyplus.gov/)_
- Works with free and pro versions of SketchUp
- Available for Windows initially (Mac later)

## SketchUp in the Design Process

- Conceptual Phase:
- Quickly create building form and massing
- Present design proposals to client
- Changes based on client feedback
- Design Development:
- Export from SketchUp to CAD tool
- Design refinement with CAD

## SketchUp in the Design Process

- Conceptual Phase:
- Quickly create building form and massing
- Present design proposals to client
- Changes based on client feedback
- Changes based on simulation feedback  
- Design Development:
- Export from SketchUp to CAD tool
- Design refinement with CAD

## Open/Edit an Input File

## Open/Edit an Input File

## Edit a Zone

## Info Tool

## Run Simulation

## Run Simulation

## Prototype Building Wizard

## Prototype Building Wizard

- Input
- Code standard
- Location
- Construction type
- Building type
- Total floor area
- Building shape:  Rect, H, L, U, T, Courtyard
- Other:  Window fractions, daylighting, overhangs, fins, HVAC system type, service hot water, PV
- Output
- EnergyPlus input file of prototype “starter” model

## Compliance Building Wizard

**Notes:**
For performance-based compliance checking.

## Compliance Building Wizard

- Input
- Code standard
- Location
- Construction type
- Building type
- Output
- EnergyPlus input file of compliance model

## Compliance Building Wizard

- What changes:
- Insulation levels
- Window performance
- Window-to-wall ratio
- Lighting power density
- HVAC system
- What does not change:
- Building form/geometry
- People and equipment loads (optional)

## EnergyPlus Plugin, Version 1.0

- Goals
- Make entering 3-D geometry _*easy*_
- Automatic prototype or compliance models
- Audience
- Current E+ users
- Prospective E+ adopters

## EnergyPlus Plugin, Version 2.0

- Goals
- Manage and edit most simulation inputs
- Audience
- Simulation experts
- Brave architects

## EnergyPlus Plugin, Version X.X

- Goals
- “Simulation for everyone”
- Appeal similar to Energy-10
- Audience
- Engineers
- Architects
- Homeowners

**Notes:**
SketchUp mantra is “SketchUp is 3D for everyone”.

- SketchUp / Energy Design Plugin Demo

## Who’s Using EnergyPlus?

- 68,000+ copies downloaded since Version 1.0 in April 2001 (all releases).
- 8,000+ copies per twice-yearly release.
- Nearly 15,000 in last 12 months alone.
- More than 120 countries.
- 1700 people on EnergyPlus_Support email list.
- And a few buildings where EnergyPlus was used...

## Buildings Designed Using EnergyPlus

- San Diego Supercomputer Center
- Thermal simulation
- Natural displacement ventilation analysis
- Climate analysis
- San Francisco Federal Building
- Natural cross ventilation system
- No mechanical cooling in high-rise portion
- Building management controls

## Buildings Designed Using EnergyPlus

- Freedom Tower
- Building energy simulation of alternatives
- Aggressive energy and environmental goals
- Code compliance
- New York Times
- Building energy simulation of alternatives
- Controls, peak demand, energy use impacts

## Buildings Designed Using EnergyPlus

- Evergreen Valley College Arts Center, San Jose, California
- Low energy cooling including natural ventilation and radiant floor systems
- Heritage Middle School, Minnesota
- 173,000 ft2 new school
- Load calculation and evaluation of energy efficiency measures

## Support Resources

- EnergyPlus Website (www.energyplus.gov)
- Free program download
- Documentation
- Weather data (more than 2100 locations worldwide)
- Testing and validation reports
- Developer & commercial distribution licenses

## Support Resources (cont’d)

- User Support Helpdesk
- _[energyplus.helpserve.com](http://energyplus.helpserve.com/)_
- Knowledgebase
- Downloads
- Submit questions
- via web: _[energyplus.helpserve.com](http://energyplus.helpserve.com/)_
- via e-mail: _[EnergyPlus-Support@gard.com](mailto:EnergyPlus-Support@gard.com)_
- Attach input files as needed

## Support Resources (cont’d)

- EnergyPlus Yahoo Technical Group
- User-to-user forum
- Join EnergyPlus-Support Yahoo Group_[http://groups.yahoo.com/group/EnergyPlus_Support](http://groups.yahoo.com/group/EnergyPlus_Support)_
- Subscribe by sending e-mail to_[EnergyPlus_Support-subscribe@yahoogroups.com](mailto:EnergyPlus_Support-subscribe@yahoogroups.com)_
- Post messages by sending e-mail to_[EnergyPlus_Support@yahoogroups.com](mailto:EnergyPlus_Support@yahoogroups.com)_

## EnergyPlus

- Designed for flexibility and expansion
- Many new low-energy technologies
- Sub-hourly calculations
- Many output metrics:  energy, water, emissions.
- Interfaces available including web file generator and SketchUp Energy Design Plugin
- Web site:  energyplus.gov
- Free download.
- 3500 pages of documentation and testing/validation reports.
- Weather data for 2100 locations worldwide            (Google Earth layer for the weather data)

## DOE Building Technologies Programbuildings.energy.govEnergyPlusenergyplus.gov

- Thanks!
- Drury.Crawley@ee.doe.gov