energyplus university course

Introduction to Building Simulation and EnergyPlus

Undergraduate Course Curriculum Information July 31, 2003

Intent The intent of this document is to present a draft curriculum outline for an undergraduate course that teaches the student about the usage of EnergyPlus. While not all of the curriculum will necessarily be specific to the EnergyPlus program, the vast majority is intended to instruct the student on how EnergyPlus works and what information it needs as input and provides as output.

Assumptions Every university is slightly different in how it approaches courses, and every instructor will approach a course differently as well. Several assumptions will be made that will help focus the development of this course:

This course is intended to be taught primarily to upper-level undergraduate students at the (USA) university level but could also be taught at the graduate level.

The primary audience is a student in mechanical or architectural engineering who has had background courses in heat transfer and thermodynamics. Instructors in affiliated fields such as civil engineering, architecture, etc. may need to supplant some of the lecture material with more basic information on heat transfer, thermodynamics, engineering analysis, etc.

This course is designed for a university on the semester system where a semester lasts approximately 15 weeks.

The lectures will be designed for a traditional 50-minute lecture period and three class sessions per week will be assumed.

It is imperative that students spend supervised time in computer laboratories to gain more experience using the program and the input language. Thus, some of the class periods will be assumed to meet in a computer laboratory rather than a lecture hall.

Based on the assumptions of 15 weeks and 3-50minute class periods per week, a total of 45 class sessions are available for course introduction, lectures, laboratories, reviews, exams or presentations, etc.

Since there is currently no interface for EnergyPlus, the lectures will be developed without referring to any interface. The IDF Editor and EP-Launch can be used in computer laboratories as desired. Existing templates may also be utilized.

Complete expertise in EnergyPlus cannot be gained in a single semester. Thus, this course will strive to give the student a working knowledge of most features of

the program rather than expertise in a specific area. Again, no interface will be assumed (this affects what material must be covered in the lectures).

Lectures must also provide adequate enough background about what is being simulated so that the students understand what not just how.

General Breakdown of Class Sessions Based on the assumptions listed in the previous section, the following breakdown of the 45 class sessions can be made. The main focus of this project is to develop the lectures and example assignments. Course syllabi, exams, homework assignments, reviews, course evaluations, etc. are left to the discretion of the individual instructors who will have specific ideas, formats, etc. about what these should be and look like.

Course Syllabus and Class Overview1 Session Formal Lectures (PowerPoint Slide Shows Provided)26 Sessions Computer Laboratories (Example Exercises to be developed by Instructor, see

section later in this documents for more notes on this)14 to 15 Sessions, some of which may be used as semester project work sessions

Exams and/or Presentation of Semester Projects2 to 3 Sessions Final Review, Course Evaluations, Wrap-up1 Session

Class Outline/Schedule (With Semester Projects) In many cases, the lessons learned and knowledge gained by a course in EnergyPlus is best applied not only through application assignments but also a semester project that deals with using EnergyPlus. The main goal would be to demonstrate the use of EnergyPlus to model an existing building or a building design. Instructors could also require students to compare the results with measured building data and/or perform the analysis or retrofit or design options to improve the overall performance of the building. The following schedule is intended to work with a course that uses a project to test student comprehension rather than exams. Obviously, individual instructors are free to adapt the schedule and lecture material as they see fit. In some cases, instructors may wish to use the example assignments sparingly and focus more on student projects. Note that an accompanying spreadsheet contains the number of slides for each of the individual lectures. Note that some lectures are too long to cover in one hour and this may require an adjustment of the schedule. Lectures 4 and 14 are examples of lectures that may require two hours to cover. Again, discretion is left up to the individual instructor as to whether material will be skipped or lectures will be enhanced. Thus, the schedule is merely a starting point that will need to be customized. Computer laboratories may include activities other than input file creation (such as looking up and/or downloading weather data or documentation, research on materials or construction techniques, etc.) Week Class Type Description Week 1 General Class Overview and Discussion of Course

Syllabus

Week 1 Lecture 1 EnergyPlus Overview (Program History, Files Overview, Web Resources)

Week 1 Computer Laboratory 1 Intro to/Demo of IDF Editor/EP-Launch/Install Week 2 Lecture 2 Running EnergyPlus and Output Week 2 Lecture 3 Output Variables, Meters, Reports Week 2 Computer Laboratory 2 Introduction to Output Week 3 Lecture 4 Simulation control, weather, location, ground

temperature Week 3 Lecture 5 Materials, Constructions, Surfaces, Zones,

Buildings Week 3 Computer Laboratory 3 Run Control and Weather Information Exercise Week 4 Lecture 6 Materials, Constructions, Surfaces, Zones,

Buildings Week 4 Lecture 7 Building Modeling Questions Week 4 Computer Laboratory 4 Building Envelope Exercise Week 5 Lecture 8 Schedules, Internal Gains, Infiltration Week 5 Lecture 9 Windows, Daylighting Week 5 Computer Laboratory 5 Scheduled Heat Gains and Zone Controls

Exercise Week 6 Lecture 10 Zone and Modeling Controls, Purchased Air Week 6 Lecture 11 Simple Ventilation, Mixing/Cross Mixing,

COMIS Week 6 Computer Laboratory 6 Windows and Daylighting Exercise Week 7 Lecture 12 Green Input: Trombe Wall,

Movable/Transparent Insulation, Thermal Mass, etc.

Week 7 Lecture 13 Loops, Nodes, Branches, Connectors Week 7 Computer Laboratory 7 Air Movement and Green Features Exercise Week 8 Lecture 14 Air Loops and Zone Equipment Week 8 Lecture 15 Air Loops and Zone Equipment Week 8 Computer Laboratory 8 Semester Project Work Session Week 9 Lecture 16 Air Loops and Zone Equipment Week 9 Lecture 17 Air Loops and Zone Equipment Week 9 Computer Laboratory 9 Air Loops and Zone Equipment Exercise Week 10 Lecture 18 Templates and Autosizing Week 10 Lecture 19 Outside Air Week 10 Computer Laboratory 10 Semester Project Work Session Week 11 Lecture 20 Radiant Systems Week 11 Lecture 21 Plant/Condenser Loops and Equipment Week 11 Computer Laboratory 11 Radiant System Exercise Week 12 Lecture 22 Plant/Condenser Loops and Equipment Week 12 Lecture 23 Plant/Condenser Loops and Equipment Week 12 Computer Laboratory 12 Plant and Condenser Loop Exercise

Week 13 Lecture 24 Ground Heat Transfer Week 13 Lecture 25 TBD or Catch up/Lecture 4b Week 13 Lecture 26 TBD or Catch up/Lecture 14b Week 14 Computer Laboratory 13 Semester Project Work Session Week 14 Computer Laboratory 14 Semester Project Work Session Week 14 Computer Laboratory 15 Semester Project Work Session Week 15 Project Presentations In-Class Presentations By Students Week 15 Project Presentations In-Class Presentations By Students Week 15 General Final Review, Course Evaluations, Class Wrap-

up

Class Outline/Schedule (With Exams/Quizzes) The content and goals for this class are the same as for the project class except that exams are used to further and test student comprehension of EnergyPlus. However, the schedule is slightly altered to allow time for exams. Week Class Type Description Week 1 General Class Overview and Discussion of Course

Syllabus Week 1 Lecture 1 EnergyPlus Overview (Program History, Files

Overview, Web Resources) Week 1 Computer Laboratory 1 Intro to/Demo of IDF Editor/EP-Launch/Install Week 2 Lecture 2 Running EnergyPlus and Output Week 2 Lecture 3 Output Variables, Meters, Reports Week 2 Computer Laboratory 2 Introduction to Output Week 3 Lecture 4 Simulation control, weather, location, ground

temperature Week 3 Lecture 5 Materials, Constructions, Surfaces, Zones,

Buildings Week 3 Computer Laboratory 3 Run Control and Weather Information Exercise Week 4 Lecture 6 Materials, Constructions, Surfaces, Zones,

Buildings Week 4 Lecture 7 Building Modeling Questions Week 4 Computer Laboratory 4 Building Envelope Exercise Week 5 Lecture 8 Schedules, Internal Gains, Infiltration Week 5 Lecture 9 Windows, Daylighting Week 5 Exam 1 Week 6 Computer Laboratory 5 Scheduled Heat Gains and Zone Controls

Exercise Week 6 Lecture 10 Zone and Modeling Controls, Purchased Air Week 6 Lecture 11 Simple Ventilation, Mixing/Cross Mixing,

COMIS Week 7 Computer Laboratory 6 Windows and Daylighting Exercise

Week 7 Lecture 12 Green Input: Trombe Wall, Movable/Transparent Insulation, Thermal Mass, etc.

Week 7 Lecture 13 Loops, Nodes, Branches, Connectors Week 8 Computer Laboratory 7 Air Movement and Green Features Exercise Week 8 Lecture 14 Air Loops and Zone Equipment Week 8 Lecture 15 Air Loops and Zone Equipment Week 9 Computer Laboratory 8 Air Loops and Zone Equipment Exercise Week 9 Lecture 16 Air Loops and Zone Equipment Week 9 Lecture 17 Air Loops and Zone Equipment Week 10 Exam 2 Week 10 Computer Laboratory 9 Air Loops and Zone Equipment Exercise Week 10 Lecture 18 Templates and Autosizing Week 11 Lecture 19 Outside Air Week 11 Computer Laboratory 10 Air Loops, Templates, and Autosizing Exercise Week 11 Lecture 20 Radiant Systems Week 12 Lecture 21 Plant/Condenser Loops and Equipment Week 12 Computer Laboratory 11 Radiant System Exercise Week 12 Lecture 22 Plant/Condenser Loops and Equipment Week 13 Lecture 23 Plant/Condenser Loops and Equipment Week 13 Computer Laboratory 12 Plant and Condenser Loop Exercise Week 13 Lecture 24 Ground Heat Transfer Week 14 Lecture 25 TBD or Catch up/Lecture 4b Week 14 Exam 3 Week 14 Lecture 26 TBD or Catch up/Lecture 14b Week 15 Computer Laboratory 13 Independent Research Assignment Week 15 Computer Laboratory 14 Independent Research Assignment Week 15 General Final Review, Course Evaluations, Class Wrap-

up

Lecture Examples and Homework Assignments Examples and case studies have been used through the lectures to provide the students with some insight into the workings of EnergyPlus and also to initiate discussions between the instructor and the students. The lectures do not claim to be exhaustive in covering every detail that could potentially be investigated or discussed in class. Some examples might be overly complex for some of the students. Instructors may wish to replace examples and case studies with ones from their own course material or create new ones that focus on more specific topics or that allow a particular effect to be analyzed. Instructors may also wish to assign simpler examples or targeted case studies as homework assignmentsallowing the students to gain experience with the program and to take time outside of class to think through particular issues involved with simulating buildings.

In addition, while is some cases, instructors will have homework assignments and examples that used other simulation programs which they wish to convert to EnergyPlus examples, other instructors may not have a library of examples and homework assignments. The lectures developed for this university course were a part of a larger research project that also developed lectures for professionals. These professional series lectures also included workshops that could be used as homework assignments. Information on where to locate these workshops should be available at the NREL web site.

Concluding Comments We hope that you enjoy the lectures provided in this course and will find them useful in your teaching efforts. You may only use part of the material for an unrelated course, you may use the lectures as they are, or you may modify/enhance the lectures to suit the particular focus of your course. The authors of this lecture series hope that instructors using these materials will share their experiences and improvements with NREL so that others instructors and the students can benefit from the collective body of knowledge in this area.

Lecture 1: An Overview of Simulation and EnergyPlus

Material prepared by GARD Analytics, Inc. and University of Illinois at Urbana-Champaign under contract to the National Renewable Energy

Laboratory. All material Copyright 2002-2003 U.S.D.O.E. - All rights reserved

2

Purpose of this Lecture

Gain an understanding of Simulation as a Concept EnergyPlus as a Simulation Tool

Briefly review topics important to your understanding of building thermal simulations

3

What is Simulation?

Definition: the imitative representation of the functioning of one system or process by means of the functioning of another (Merriam-Webster Dictionary On-Line)

4

What is Building Thermal Simulation?

Approximate definition: a computer model of the energy processes within a building that are intended to provide a thermally comfortable environment for the occupants (or contents) of a building

Examples of building thermal simulation programs: EnergyPlus, Energy-10, BLAST, DOE-2, esp-R, TRNSYS, etc.

5

Goals of Building Thermal Simulation

Load Calculations Generally used for determining sizing of

equipment such as fans, chillers, boilers, etc.

Energy Analysis Helps evaluate the energy cost of the

building over longer periods of time

6

Why is Simulation Important?

Buildings consume roughly one-third of all the energy consumed nationally every year Much of this energy is consumed

maintaining the thermal conditions inside the building and lighting

Simulation can and has played a significant role in reducing the energy consumption of buildings

7

How does Simulation save Energy?

Building thermal simulation allows one to model a building before it is built or before renovations are started

Simulation allows various energy alternatives to be investigated and options compared to one another

Simulation can lead to an energy-optimized building or inform the design process

Simulation is much less expensive and less time consuming than experimentation (every building is different)

8

Quick Review of Important Background Concepts

Control Volumes and the Conservation of: Mass Energy (First Law of Thermodynamics)

Heat Transfer Mechanisms: Conductiontransfer of thermal energy through a

solid Convectionexchange of thermal energy between

a solid and a fluid that are in contact Radiationexchange of thermal energy via

electro-magnetic waves between bodies or surfaces

9

What is EnergyPlus?

Fully integrated building & HVAC simulation program

Based on best features of BLAST and DOE-2 plus new capabilities

Windows 95/98/NT/2000/XP & Linux Simulation engine only Interfaces available from private

software developers

10

EnergyPlus Concepts

Time dependent conduction Conduction through building surfaces calculated

with conduction transfer functions Heat storage and time lags

Migration between zones Approximates air exchange using a nodal model

Only models what is explicitly described Missing wall does not let air in Missing roof does not let sun in

11

EnergyPlus Concepts (contd)

Heat balance loads calculation (one of two load calculation methods recommended by ASHRAE)

Moisture balance calculation Simultaneous building/systems solution Sub-hourly time steps Modular HVAC system simulation WINDOW 5 methodology

12

EnergyPlus Concepts (contd)

Simple input/output file structures No surface, zone or system limits

Defaults to 50 coils per HVAC loop Can be increased

Links to other software COMIS, wind-induced airflow TRNYSYS, Photovoltaics

13

EnergyPlus Structure

14

Integrated Simulation Manager

Fully integrated simulation of loads, systems and plant Integrated simulation allows capacity limits

to be modeled more realistically Provides tighter coupling between the air-

and water-side of the system and plant

15

Integrated Simulation Manager (contd)

16

Input/Output Data

EnergyPlus input and output data files designed for easy maintenance and expansion

Will accept simulation input data from other sources such as CADD programs (AutoCAD, ArchiCAD, Visio), and preprocessors similar to those written for BLAST and DOE-2

An EnergyPlus input file is not intended to be the main interface for typical end-users

17

Input/Output Data (contd)

Most users will use EnergyPlus through an interface from a third-party developer

Utilities convert portions of BLAST and DOE-2 input to EnergyPlus input Materials and constructions Schedules Building envelope surfaces

18

Summary

EnergyPlus builds on the strengths of BLAST and DOE-2 and includes many new simulation capabilities: Integrated loads, system and plant calculations in

same time step. User-configurable HVAC system description. Modular structure to facilitate the addition of new

simulation modules. Simple input and output data formats to facilitate

graphical front-end development.

19

Basic Input and Output Issues

General Philosophy Input/Output Files

Overall File Structures Input Object Structure

Input Data Dictionary (IDD) Weather Files

20

General Philosophy of Input/Output/Weather

Simple, free-format text files SI units only Comma-separated Object-based Somewhat self-documenting Two partsdictionary and data or simulation

results Not user-friendly Interfaces will help Can become large

21

InputOutput Files

Input Data Dictionary This file is created by

EnergyPlus developers.

Input Data File

This file will be created

by User

Object,data,data,,data;

Object,data,data,,data;

Input Data Dictionary (IDD)

EnergyPlus Program Main Program

Module

Module

Module

Module

Module

Module

File Types: Standard Reports Standard Reports (Detail) Optional Reports Optional Reports (Detail) Initialization

Reports Overview of File Format:

Header Data Dictionary Data Note: These files will be

created by EnergyPlus.

Output Files

Out

put P

roce

ssor

Input Data Files (IDF)

22

Input Object Structure

Begin with object type followed by comma A (alpha) and N (numeric) fields in exact order Fields separated by commas Last field followed by semi-colon Commas are necessary placeholders BASEBOARD HEATER:Water:Convective, Zone1Baseboard, !- Baseboard Name FanAndCoilAvailSched, !- Available Schedule Zone 1 Reheat Water Inlet Node, !- Inlet_Node Zone 1 Reheat Water Outlet Node, !- Outlet_Node 500., !- UA {W/delK} 0.0013, !- Max Water Flow Rate {m3/s} 0.001; !- Convergence Tolerance

23

Input Object Structure (contd)

Alpha fields 60 characters maximum ! exclamation point begins comments IDF objects can be in any order

IDF Editor may rearrange the order !- IDF Editor automated comments IDF Editor cannot be used with HVAC Templates

BASEBOARD HEATER:Water:Convective, Zone1Baseboard, !- Baseboard Name FanAndCoilAvailSched, !- Available Schedule Zone 1 Reheat Water Inlet Node, !- Inlet_Node Zone 1 Reheat Water Outlet Node, !- Outlet_Node 500., !- UA {W/delK} 0.0013, !- Max Water Flow Rate {m3/s} 0.001; !- Convergence Tolerance

24

Input Object Structure (contd)

Not case-sensitive Input processor checks basic rules, A vs. N, number

of fields, valid object type, max/min, etc. IDF objects are generally retrieved by each

component simulation module BASEBOARD HEATER:Water:Convective, Zone1Baseboard, !- Baseboard Name FanAndCoilAvailSched, !- Available Schedule Zone 1 Reheat Water Inlet Node, !- Inlet_Node Zone 1 Reheat Water Outlet Node, !- Outlet_Node 500., !- UA {W/delK} 0.0013, !- Max Water Flow Rate {m3/s} 0.001; !- Convergence Tolerance

25

Input Data Dictionary (IDD File)

Energy+.idd Located in

EnergyPlus folder Conceptually simple

A (alpha) or N (Numeric)

BASEBOARD HEATER:Water:Convective, A1 , \field Baseboard Name \required-field A2 , \field Available Schedule \required-field \type object-list \object-list ScheduleNames . . . N1 , \field UA \required-field \autosizable \units W/delK . . . N3 ; \field Convergence Tolerance \type real \Minimum> 0.0 \Default 0.001

26

IDD File (contd)

Lists every available input object If it isnt in the IDD, then its not available IDD version must be consistent with exe

version IDD is the final word (even if other

documentation does not agree)

27

IDD File (contd)

\code Specifications Field descriptions Units Value ranges (minimum, maximum) Defaults Autosizing

28

IDD File (contd)

Get to know the IDD file Easy way to quickly check object syntax Refer to Input Output Reference for

detailed explanations of inputs

29

Allowable Ranges and Defaults

Allowable ranges Some max/min declared in IDD

Fatal error if outside of range Some max/min hidden in source code

May reset value and issue warning, may be fatal

Defaults Some defaults declared in IDD Some defaults hidden in source code Some values have no defaults

Alphas become blank Numerics become zero

30

Weather Data (epw file)

Weather year for energy use comparisons, similar to other programs

Hourly, can be subhourly Hourly data is linearly interpolated Data include temperature, humidity,

solar, wind, etc. Several included in standard install

31

Output Data Format

Same philosophy as for input; somewhat human readable output files

EnergyPlus can perform some output processing to help limit output size

User definable variable level reporting

32

Output Reporting Flexibility

User can select any variables available for output

User can specify output at time step, hourly, daily, monthly, or environment intervals

User can schedule each output variable User can select various meters by

resource and end-use

33

Questions

How long will my simulation take? Depends on size of input file, length of

simulation period (day vs. year), and speed of computer

Might range from a few seconds to several minutes (some detailed simulation modules may require even longer)

EnergyPlus will display progress in a window on the desktop so that the user knows where it is at

34

Questions (contd)

How do I know whether the program read my input correctly? Take a look at the .EIO file (EnergyPlus initialization

output)this may indicate that you have misinterpreted an input parameter

Check results output files and see if they are reasonable How will I know whether my simulation results are

reasonable or outrageous? See previous question Consider Load Check Figures available from sources such

as ASHRAE Compare to other simulations or consult your instructor Do some simple hand calculations (such as UAT) and see if

the numbers are in the ballpark

Computer Laboratory 1: Installing and Using EnergyPlus



2


Gain an understanding of How to Install EnergyPlus How to Use EnergyPlus Auxiliary Programs and Documentation for

EnergyPlus

3

Installing EnergyPlus

EnergyPlus Components EnergyPlus Folders

4

Installing EnergyPlus

Documentation 12759k EP-Launch 1819k IDFEditor 415k SampleFiles 29065k WeatherConvertor 2428k BLASTTranslator 4978k DOETranslator 663k

GroundHeatTransferPreProcessor 770k

IFCtoIDF 2910k Included in default installation

Select Components Menu

5

Installing EnergyPlus (contd)

After installation the EnergyPlus directory will contain the following subdirectories (if default components are selected):

BACKUP DataSets Documentation Example Files PostProcess

PreProcess Templates Trnsysspv WeatherData

6

EnergyPlus Folders

EnergyPlus Location selected during

install Default is c:\EnergyPlus Batch files Executables Readme

7

DataSets Folder

DataSets Predefined Objects Locations Design Days Materials Constructions Schedules and more

MacroDataSets ##if blocks for

parametric batch runs

8

Documentation Folder

Documentation User & Developer

Documentation Bookmarks to

Navigate Searchable PDF Format Requires Acrobat

Reader 5.0 or higher (www.adobe.com)

9

ExampleFiles Folder

ExampleFiles Dozens of example

inputs Named by key

feature e.g., CVBbRh.idf Many concepts are

best learned by example

10

WeatherData Folder

WeatherData User can download additional EPW weather files at

www.energyplus.gov

11

Start Menu Shortcuts

Start Programs EnergyPlus Vn-n-n Programs

DocMainMenu Docs Menu Page

EP-Launch Easy-to-Use Run Tool

IDFEditor Input File Editor

12

Start Menu Shortcuts (contd)

IFCtoIDF Convert IFC Files

WeatherConverter Process Weather

Data Create Weather

Reports

13

User Documentation

Eplus Main Menu EnergyPlus\Documentation\

EPlusMainMenu.pdf Start Programs

EnergyPlus Programs DocMainMenu

Getting Started Input Output Reference Output Details and Examples Engineering Reference Auxiliary Programs/Developer

Guides Frequently Asked Questions

14

Auxiliary Tools

Run-time Tools EP-Launch

Input/Output Tools IDF Editor WinEPDraw

15

EP-Launch

Assistance in running EnergyPlus Reads EPL-Run.bat file Creates RunEP.bat file and executes Displays run status (eplusout.end) Can view all input and output Files Several user options available

16

EP-Launch

Select and edit input file

Select weather file

View output files

Run EnergyPlus

Access EnergyPlus documentation

17

EP-Launch Setup

Select desired text editor program (defaults to .txt editor)

Select drawing viewer for DXF files (VoloView Express is free from www.autodesk.com)

Select desired spreadsheet program to view csv files

18

EP-Launch Options

Open only ERR and EIO output files

Pause batch file after EnergyPlus execution to read traceback if crash

Wide format for long path names

19

EP-Launch Alternate Layout

20

Results

ERR file contains warnings and errors (always look here!)

EIO file contains additional EnergyPlus results, including verification of location, environment, summary reports, etc.

View menu ERR/EIO only (F2) RDD file lists the output variables

available from the run

21

Results (contd)

ESO file contains the raw output from the run (users rarely look here)

CSV versions of ESO and MTR files can be opened by clicking on the Spreadsheet button Can be imported into any spreadsheet program

that accepts the CSV format

DXF file can be viewed by clicking on the Drawing File button Can be imported into any CAD program that

accepts the DXF format

22

IDF Editor

Not really an interface Reads IDD Structures data entry based on IDD Writes objects in IDD order

e.g. Run Period, Design Days, all Materials, all Constructions, all Zones, all Surfaces

Files generated by other means will be rearranged

CANNOT read IMF files (see EP-Macro)

23

IDF Editor

Select object type from class list

Objects shown here for selected class

Pull-down list of keywords or references when applicable

Description of entry, max and min when applicable

24

WinEPDraw

Creates dxf drawing Does not run simulation *.epderr file reports errors Run independently EP-Launch drawing button will run if

dxf file not present dxf file older than idf

25

Summary

EnergyPlus install includes documentation and example files

Various auxiliary programs can be used with EnergyPlus when a more sophisticated interface is not available, the most important utilities are: EP-Launch (launches EnergyPlus) IDF Editor (edits input files for EnergyPlus)

Lecture 2: Simulating Buildings and EnergyPlus Auxiliary Programs



2

Importance of this Lecture to the Simulation of Buildings

Simulation of buildings requires 3 main steps: Creation of Building Model (Input Definition) Utilizing a Simulation Program (Running/Debugging Input) Analysis of Simulation Results (Output)

Most of the lectures in this course focus on the first of the three steps since this is where most of your time will be spent

However, using a program and understanding its output is as critical to the proper use of simulation

This lecture focuses on the last two steps since they will be useful throughout the semester and will restrict the discussion to the program we are using this semester: EnergyPlus

3


Gain an understanding of the following EnergyPlus related issues Simulation Types EnergyPlus Files Auxiliary Programs EnergyPlus Output Handling Errors in Input

4

Simulation Types

Peak Thermal Load Calculation Simulation run for an extreme (design) day or several design

days Generally used for determining sizing of equipment such as

fans, chillers, boilers, etc.

Building Energy Analysis Simulation run for an extended period of time: a month,

season, year, or several years using weather files Includes the building response to the entire range of

conditions expected at a particular site Helps evaluate the energy cost of the building over longer

periods of time

5

EnergyPlus Files

Let EP-Launch or RunEPlus.bat worry about getting files into the right place

Simple, console app concept Energy+.idd constant Energy+.ini working file paths In.idf input data file In.epw weather data

Input files in working directory Execution from working directory

6

Files Overview

Simple ASCII files Simple input format (self-contained) User-defined output (comma separated

data) can be interpreted by many programs Spreadsheets Databases Custom Programs

Note: be advised that the use of some word processing programs to create input files may result in errors due to their use of non-simple carriage returns. Notepad works well if one is trying to create input files by hand.

7

EP-Launch

Assistance in running EnergyPlus Reads EPL-Run.bat file Creates RunEP.bat file and executes Displays run status (eplusout.end) Can view all input and output files Several user options available

8

EP-Launch

Select and edit input file

Select weather file

View output files

Run EnergyPlus

Access EnergyPlus documentation

9

EP-Launch Setup

Select desired text editor program (defaults to .txt editor)

Select drawing viewer for DXF files (VoloView Express is free from www.autodesk.com)

Select desired spreadsheet program to view csv files

10

EP-Launch Options

Open only ERR and EIO output files

Pause batch file after EnergyPlus execution to read traceback if crash

Wide format for long path names

11

EP-Launch Alternate Layout

12

IDF Editor

Not really an interface Reads IDD Structures data entry based on IDD Writes objects in IDD order

e.g. Run Period, Design Days, all Materials, all Constructions, all Zones, all Surfaces

Files generated by other means will be rearranged

CANNOT read IMF files (see EP-Macro) Some tasks must be done in text editor

13

IDF Editor

Select object type from class list

Objects shown here for selected class

Pull-down list of keywords or references when applicable

Description of entry, max and min when applicable

14

WinEPDraw

Creates dxf drawing Does not run simulation *.epderr file reports errors Run independently EP-Launch drawing button will run if

dxf file not present dxf file older than idf

15

Results

ERR file contains warnings and errors (always look here!)

EIO file contains additional EnergyPlus results, including verification of location, environment, summary reports, etc.

View menu ERR/EIO/BND only (F2) RDD file lists the output variables

available from the run

16

Results (contd)

ESO file contains the raw output from the run (users rarely look here)

CSV versions of ESO and MTR files can be opened by clicking on the Spreadsheet button Can be imported into any spreadsheet program

that accepts the CSV format

DXF file can be viewed by clicking on the Drawing File button Can be imported into any CAD program that

accepts the DXF format

17

Input Error Detection

Input Processor checks field type, max, min, required fields, based on IDD specifications

Inputs are not processed sequentially Simulation modules perform additional checks Certain errors will terminate program before

all input has been retrieved by simulation modules

Previously undetected errors may be reported after fixing other errors

18

Error Diagnostics

ERR file reports any errors that may have occurred during the simulation Error messages may be generated during

its input phase or during the simulation Error messages usually identify specific

object type and name related to the error Use search command to locate error in IDF file

19

Error Diagnostics (contd)

Four levels of error severity: Message Informative. No action

required. Warning Take note. Fix as applicable. Severe Should fix. Program may abort. Fatal Program will abort

20


Running EnergyPlus with CVBbRh.idf results in the following Err file:

Program Version,EnergyPlus, Version 1.1.1 ** Warning ** Version in IDF="1.1" not the same as expected="1.1.1" ** Warning ** World Coordinate System selected. Some Zone Origins are non-zero. ** ~~~ ** These will be used in Daylighting:Detailed calculations but not in normal geometry inputs. ************* Testing Individual Branch Integrity ************* All Branches passed integrity testing ************* Testing Individual Supply Air Path Integrity ************* All Supply Air Paths passed integrity testing ************* Testing Individual Return Air Path Integrity ************* All Return Air Paths passed integrity testing ************* No node connection errors were found. ** Warning ** The following lines are "Orphan Objects". These objects are in the idf ** ~~~ ** file but are never obtained by the simulation and therefore are NOT used. ** ~~~ ** See InputOutputReference document for more details. ************* Object=FLUIDNAMES=WATER ************* Object=FLUIDPROPERTYTEMPERATURES=GLYCOLTEMPERATURES ************* Object=FLUIDPROPERTYCONCENTRATION=WATER ************* EnergyPlus Completed Successfully-- 3 Warning; 0 Severe Errors; Elapsed Time=00hr 00min 06sec

Only messages and warningsEnergyPlus ran successfully

21


Typo in file BUILDING, NONE, !- Building Name 0.0000000E+00, !- North Axis {deg} Suburbs, !- Terrain 3.9999999E-02, !- Loads Convergence Tolerance Value {W} 0.4000000, !- Temperature Convergence Tolerance Value {deltaC} FullInteriorAndExterior; !- Solar Distribution abcdefg SOLUTION ALGORITHM, CTF; !- SolutionAlgo

Typo here

22


Err file error message

Program Version,EnergyPlus 1.1.0.018, 4/23/2003 9:40 AM ************* IDF Line=28 abcdefg ** Severe ** , or ; expected on this line

23


*.audit file for context Search for error flag

20 BUILDING, 21 NONE, !- Building Name 22 0.0000000E+00, !- North Axis {deg} 23 Suburbs, !- Terrain 24 3.9999999E-02, !- Loads Convergence Tolerance Value {W} 25 0.4000000, !- Temperature Convergence Tolerance Value {deltaC} 26 FullInteriorAndExterior; !- Solar Distribution 27 28 abcdefg ** Severe ** , or ; expected on this line 29

Typo here

Error message here

24


Crashes EP-Launch indicates that EnergyPlus crashed EP-LaunchView MenuPause During Simulation

- adds a pause to view traceback Name of failed routine may provide a clue to

where the problem lies, e.g., CalcSimple Cooling Coil

25


26


Reports Report, Surfaces, DXF

DXF file that will render the surfaces specified in the IDF file into something viewable

Report, Surfaces, Details Lists all surfaces with area, azimuth, tilt, construction

and surface type

Report Variable Dictionary Allows determination of all of the key strings to specify

report variables in the input files (produces RDD file)

Report, Construction Lists thermal properties of all construction types

27


Common Errors Missing comma or semicolon Inappropriate zero value Upside down roof or floor HVAC missing components HVAC misconnected nodes Empty objects in IDF Editor

28

Summary

Two main simulation categories: Thermal load calculations Energy analysis

Important input files for EnergyPlus: Energy+.idd and Energy+.ini In.idf and in.epw

EP-Launch used to select input files and weather as well as executing EnergyPlus

29

Summary (contd)

Output and error diagnostics: *.err (and *.audit) messages are not necessarily

problems Messages and warnings may or may not be

important to the simulation (informational in many cases)

Severe and fatal errors need to be addressed Other output files (*.eso, *.csv, *.dxf, *.eio) can

also aid in determining problems in user input

Lecture 3: OutputReports, Variables, and Meters



2


Running a simulation program results in the production of output data

Understanding the output data and its format can help avoid mistakes and save time

3


Gain an understanding of: Different output files of EnergyPlus Which output will be the most useful and

how to get it Define accumulation meters to save time

in processing and analyzing results

4

Keywords Covered in this Lecture

Report Report Variable Report Meter

5

Output Data Format

Same philosophy as for input; somewhat human readable output files

EnergyPlus can perform some output processing to help limit output size

User definable variable level reporting

6

Output Reporting Flexibility

User can select any variables available for output

User can specify output at time step, hourly, daily, monthly, or environment intervals

User can schedule each output variable User can select various meters by

resource and end-use

7

Types of Output

Report Variables Report Meters Default Reports Optional Reports

8

Output Files

Eplusout. Filename. eio Initialization Output environments,

constructions, global settings eso Standard Output numeric data csv csv spreadsheet of eso data err Errors Output always review this! rdd Report Data Dictionary list of valid

report variables for a particular run

9

Output Files (contd)

dxf dxf drawing of building surfaces mtr Meter output numeric data Meter.csv csv spreadsheet of meter data mtd Meter details lists which report

variables are on which meters cif Comis input file zsz Zone sizing report ssz System sizing report

Created using CVBbRh.idf

10

Output Files (contd)

bnd Branch and node details dbg Debug output trn Trnsys output sln Vertices of surface

For more details see Output Details and

Examples

11

Report Commands

Report Variable, EAST ZONE, Mean Air Temperature, Timestep;

Report Variable, *, Mean Air

Temperature, Daily, Report Schedule;

Report, Variable Dictionary; Report, Construction; Report, Surfaces, DXF; Report, Surfaces, Details;

MAT only for EAST ZONE every timestep

MAT for all zones, daily

average, only when Report Schedule equals 1

List all available variables *.rdd List material and construction

properties *.eio Produce drawing of surfaces

*.dxf List all surfaces with area, tilt,

construction, etc.

12

Report Commands (contd) Report Variable,,Outdoor Dry Bulb,monthly; Report Variable,Zone 1,Zone/Sys Sensible Cooling Energy,monthly; Report Variable,Zone 1,Zone/Sys Sensible Heating Energy,monthly; Report Variable,,Heating Coil Energy,monthly; Report Variable,,DX Coil Sensible Cooling Energy,monthly; Report Variable,,DX Coil Latent Cooling Energy,monthly; Report Variable,,DX Coil Total Cooling Energy,monthly; Report Variable,,DX Cooling Coil Electric Consumption,monthly; Report Variable,,Fan Electric Consumption,monthly; Report Variable,,Zone/Sys Air Temp,monthly; Report,Variable dictionary; Report,surfaces,dxf; Report,surfaces,details; Report,construction;

13

Output Data Dictionary (ESO File)

Data Dictionary - Beginning of Output Data File 1,5,Environment

Title[],Latitude[degrees],Longitude[degrees],Time Zone[],Elevation[m]

2,6,Day of Simulation[],Month[],Day of Month[],DST Indicator[1=yes 0=no],Hour[],StartMinute[],EndMinute[],DayType

3,3,Cumulative Day of Simulation[],Month[],Day of Month[],DST Indicator[1=yes 0=no],DayType ! When Daily Report Variables Requested

246,2,ZN001:FLR001,Surface Inside Temperature[C] !TimeStep

302,2,ZN002:FLR001,Surface Inside Temperature[C] !TimeStep

. . . End of Data Dictionary

14

Output Data (ESO File)

Output Data After the Data Dictionary 1,CHANUTE AFB ILLINOIS SUMMER, 40.30, -88.13, -6.00,

229.51 2, 1, 7,21, 0, 1, 0.00,10.00,Monday 246,33.3319029536235 302,31.7565160760406 . . .

15

ESO vs. CSV

ESO Raw data in comma separated format Stream of conscience reportvariables print as

they are determined Less convenient for viewing variables

CSV Organized data in comma separated format Each row contains data in columns for a particular

time step More convenient for viewing variables Requires an .rvi file and must run post-processing

program EP-Launch handles this automatically

16

CSV File Sample Date/Time Environment:Outdoor

Dry Bulb [C](Monthly)ZONE ONE:Zone/Sys Sensible Heating Energy[J](Monthly)

ZONE ONE:Zone/Sys Sensible Cooling Energy[J](Monthly)

ZONE ONE:Zone/Sys Air Temp[C](Monthly)

July 25.58495468 0.00E+00 19028775.23 24.4112152January -17.77778 253868837.1 0.00E+00 20.28659003January -4.63546707 4144370093 0.00E+00 20.43495965February -2.23312872 3151142586 0.00E+00 20.46221742March 1.603242608 2545318797 0.00E+00 20.54348182April 8.370677083 1431785319 324853.0522 21.20071107May 15.30398185 639305402.1 51404202.22 22.43806808June 21.09550347 164326207.4 145308752.2 23.40095162July 23.49973118 65628804.19 244539864.1 23.81873695August 21.75707325 96943677.86 103740404 23.32673507September 18.11458333 346023544.8 45088296.07 22.40959675October 11.73642473 1065565115 714539.5928 21.18788477November 4.232118056 2260965068 0.00E+00 20.49516327December -2.566599462 3853388966 0.00E+00 20.46126771

17

CSV File Sample (contd)

Part of the CSV file created when the CVBbRh.idf file is run in EnergyPlus:

Date/Time

RESISTIVE ZONE:Mean Air Temperature[C](Hourly:REPORTSCH)

EAST ZONE:Mean Air Temperature[C](Hourly:REPORTSCH)

NORTH ZONE:Mean Air Temperature[C](Hourly:REPORTSCH)

RESISTIVE ZONE:Zone/Sys Sensible Cooling Energy[J](Hourly:REPORTSCH)

EAST ZONE:Zone/Sys Sensible Cooling Energy[J](Hourly:REPORTSCH)

NORTH ZONE:Zone/Sys Sensible Cooling Energy[J](Hourly:REPORTSCH)

RESISTIVE ZONE:Zone/Sys Sensible Heating Energy[J](Hourly:REPORTSCH)

EAST ZONE:Zone/Sys Sensible Heating Energy[J](Hourly:REPORTSCH)

NORTH ZONE:Zone/Sys Sensible Heating Energy[J](Hourly:REPORTSCH)

ZONE1BASEBOARD:Baseboard Heating Rate[W](Hourly:REPORTSCH)



DETAILED COOLING COIL:Total Water Cooling Coil Rate[W](Hourly:REPORTSCH)

07/21 01:00 32.35558 31.84687 32.54195 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 07/21 02:00 31.81557 31.36997 31.94508 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 07/21 03:00 31.31389 30.93895 31.42794 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 07/21 04:00 30.84865 30.52358 30.96918 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 07/21 05:00 30.42387 30.11834 30.52752 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 07/21 06:00 30.03226 29.72461 30.09109 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 07/21 07:00 29.80721 29.84088 29.9142 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 07/21 08:00 24.12819 24.20936 24.22478 7969336 1.02E+07 1.20E+07 0.00E+00 0.00E+00 0.00E+00 4065.72 2024.82 2997.335 19442.14 07/21 09:00 24.00079 23.99989 23.99957 1.45E+07 1.33E+07 1.83E+07 0.00E+00 0.00E+00 0.00E+00 2190.512 1066.101 1132.316 18783.6 07/21 10:00 24.0007 24.0003 23.99982 1.51E+07 1.39E+07 1.89E+07 0.00E+00 0.00E+00 0.00E+00 1987.641 869.9992 944.2528 18799.07 07/21 11:00 23.99996 24.00012 24.00022 1.61E+07 1.48E+07 1.96E+07 0.00E+00 0.00E+00 0.00E+00 1708.771 635.6866 732.0659 18802.23 07/21 12:00 24.00028 24.00011 24.00003 1.72E+07 1.56E+07 2.04E+07 0.00E+00 0.00E+00 0.00E+00 1389.911 390.1691 516.0278 18803.26 07/21 13:00 23.99991 23.99997 24.00001 1.81E+07 1.62E+07 2.07E+07 0.00E+00 0.00E+00 0.00E+00 1196.966 270.4863 460.9324 18783.9 07/21 14:00 23.99956 24.01824 24.0001 1.92E+07 1.71E+07 2.17E+07 0.00E+00 0.00E+00 0.00E+00 879.5861 35.07354 196.6353 18781.08 07/21 15:00 23.99998 24.1879 24.0387 1.99E+07 1.73E+07 2.23E+07 0.00E+00 0.00E+00 0.00E+00 656.8229 0.00E+00 14.17869 18849.89 07/21 16:00 24.00017 24.35251 24.24059 2.03E+07 1.75E+07 2.26E+07 0.00E+00 0.00E+00 0.00E+00 516.8994 0.00E+00 0.00E+00 18973.62 07/21 17:00 24.00003 24.33324 24.34564 2.03E+07 1.75E+07 2.29E+07 0.00E+00 0.00E+00 0.00E+00 523.1177 0.00E+00 0.00E+00 19013.39 07/21 18:00 38.04053 35.66377 35.93962 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 07/21 19:00 36.46327 34.70622 35.23245 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 07/21 20:00 35.54667 33.74085 34.69495 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 07/21 21:00 35.21486 33.5262 34.64345 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 07/21 22:00 34.56882 33.18677 34.26335 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 07/21 23:00 33.78711 32.78502 33.74649 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 07/21 24:00 33.00431 32.36126 33.17585 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

18

RVI File

RVI: Report Variable Input List of variables to take from ESO file

and report to CSV file Example:

eplusout.eso eplusout.csv Outdoor Dry Bulb Zone/Sys Air Temp Zone/Sys Sensible Cooling Energy Zone/Sys Sensible Heating Energy FangerPMV PierceTSENS KsuTSV 0

Input file name for post-processor

Output file name for post-processor

Report Variables (see IDF or RDD file) to be taken from ESO file and reported in CSV file

End of file marker

19

Report Data Dictionary (RDD Files)

Var Type,Var Report Type,Variable Name [Units] Zone,Average,Outdoor Dry Bulb [C] Zone,Average,Outdoor Barometric Pressure [Pa] Zone,Average,Mean Air Temperature[C] HVAC,Sum,Zone/Sys Sensible Heating Energy[J] HVAC,Average,Zone/Sys Sensible Heating Rate[W]

Lists applicable output variables for a given input file

Must activate with report, variable dictionary; command

20

Meters

Accumulate multiple outputs of same form Appropriate variables are grouped onto meters for

reporting purposes May ease analysis of output Values are put onto the eplusout.mtr file Meter component details in eplusout.mtd file Meter names applicable for the simulation are shown

on the Report Data Dictionary file Meter names are of two forms:

: ::

21

Meters Resource Types

Electricity Gas Gasoline Diesel Coal FuelOil#1 FuelOil#2

Propane Water Steam PurchasedCooling PurchasedHeating EnergyTransfer (coil

& equipment loads)

22

Meters End Use Types

GeneralLights TaskLights ExteriorLights ZoneSource ExteriorEquipment Fans Pumps

Heating Cooling HeatRejection Humidifier HeatRecovery DHW Cogeneration Miscellaneous

23

Meters Meter Types

Facility (Master Meters) Submeters:

Zone (lights, plug loads, etc.) Building (all zones combined plus exterior) System (air handlers, terminal units) Plant (chillers, boilers, DHW, etc.)

24

Meters Meter Types

Zone Air loop

Plant Loop

Gas:HVAC

Elec:Plant Gas:Plant

Lights:Zone

Elec:HVAC Elec:Zone

Building System

25

Input for Meters

Report Meter, Electricity:*, Hourly;

Report Meter, Electricity:

Facility, monthly; Report Meter, Cooling:

Electricity, monthly;

All electric meters, for all end uses and all levels

Master electric meter Cooling equipment

26

Input for Meters (contd)

Report Meter,Fans:Electricity,monthly; Report Meter,Cooling:Electricity,monthly; Report Meter,Heating:Electricity,monthly; Report Meter,Electricity:HVAC,monthly; Report Meter,Electricity:Facility,monthly; Report Meter,Heating:Gas,monthly; Report Meter,Gas:HVAC,monthly; Report Meter,Gas:Facility,monthly;

27

Meter Details File

Lists exactly what is included in each meter

*.mtd output file For Meter=Electricity:Plant [J], contents are: LITTLE CHILLER:Chiller Electric Consumption [J] BIG CHILLER:Chiller Electric Consumption [J] CIRC PUMP:Pump Electric Consumption [J] COND CIRC PUMP:Pump Electric Consumption [J] HW CIRC PUMP:Pump Electric Consumption [J] BIG TOWER:Tower Fan Electric Consumption [J]

28

Output Files Summary

Simple ASCII files Simple input format (self-contained) User-defined output can be interpreted

by many programs Spreadsheets Databases Custom Programs

29

Summary

ESO (EnergyPlus Standard Output) file provides user with raw output data from EnergyPlus run

CSV file is a version of the ESO file that is in a format more readily usable in a spreadsheet program

Meters and meter output are convenient ways of grouping data for output analysis

Lecture 4: Simulation Control, Location, and Weather Input



2


Every building is different in many ways: Location and exterior thermal environment Construction HVAC system

Exterior thermal environment is a driving force that determines how a building will respond

Energy efficient design requires an understanding of and a response to the exterior thermal environment

Thermal simulation requires information on the exterior thermal environment to properly analyze the building from an energy perspective

3


Gain an understanding of how to control the exterior environment of the simulation Building Location Weather and Ground Temperature Data Length of Simulation Other General Features of the Input

4

Keywords Covered in this Lecture

Version Run Control Location DesignDay SpecialDayPeriod RunPeriod DaylightSavingPeriod GroundTemperature GroundReflectance Snow Ground Reflectance Modifiers

5

Quick Review of Relationship Between IDD and IDF Files

IDD: Input Data Dictionary File which defines what information should

be located in the user input file This file should NOT be modified

IDF: Input Data File User input file containing information about

the building and its primary and secondary systems

This file can be modified using a text editor or using the IDF Editor

6

Keyword: Version

IDD Description VERSION, \unique-object A1 ; \field Version Identifier \required-field

Notes \unique-object means only one of these

are allowed per IDF file \required-field means this field must be

present in the description

7

Keyword Example: Version

IDF Examples Version, 1.1; ! Shortened input format Version, 1.1; !- Version Identifier

Notes: The Version identifier refers to a version of the

EnergyPlus program Updates in the EnergyPlus program may result in

changes to the IDD An error message will result if the IDF file version

does not correspond to the version of EnergyPlus being run

This course is based on EnergyPlus Version 1.1

8

Keyword: Location

IDD Description (shortened)

IDD Description (detailed)

Location, A1 , \field Location Name N1 , \field Latitude N2 , \field Longitude N3 , \field TimeZone N4 ; \field Elevation

Location, \unique-object \min-fields 5 A1 , \field Location Name \required-field \type alpha

Only one per IDF file

All five fields are required

Information expected: a name

Field is a character string

9

Keyword: Location

IDD Description (detailed, continued) N1 , \field Latitude \units deg \minimum -90.0 \maximum +90.0 \default 0.0 \note + is North, - is South, degree minutes represented \note in decimal (i.e. 30 minutes is .5) \type real N2 , \field Longitude \units deg \minimum -180.0 \maximum +180.0 \default 0.0 \note - is West, + is East, degree minutes represented \note in decimal (i.e. 30 minutes is .5) \type real

Building site latitude (global position)

N1 in degrees

Limits (-90N1+90) and Default Value

Interpretation information Field is a decimal value

Building site longitude (global position)

10

Keyword: Location

IDD Description (detailed, continued) N3 , \field Time Zone \units hr \minimum -12.0 \maximum +12.0 \default 0.0 \note Time relative to GMT. Decimal hours. \type real N4 ; \field Elevation \units m \minimum -300.0 \maximum< 6096.0 \default 0.0 \type real

Political time zone

N3 in hours

Building site elevation

N4 in meters

Note

11

Keyword Example: Location

IDF Example or

Notes: Location affects the sun angles, air properties, etc.

that the building experiences

Location, DENVER, 39.750, -104.870, -7.0, 1610.26; Location, DENVER COLORADO, !- LocationName 39.750, !- Latitude {deg} -104.870, !- Longitude {deg} -7.0, !- TimeZone {hr (decimal)} 1610.26; !- Elevation {m}

12

Keyword: DesignDay

IDD Description (shortened) DesignDay, A1 , \field DesignDayName N1 , \field Maximum Dry-Bulb Temperature N2 , \field Daily Temperature Range N3 , \field Wet-Bulb Temperature At MaxTemp N4 , \field Barometric Pressure N5 , \field Wind Speed N6 , \field Wind Direction N7 , \field Sky Clearness N8 , \field Rain Indicator N9 , \field Snow Indicator N10, \field Day Of Month N11, \field Month A2 , \field Day Type N12; \field Daylight Saving Time Indicator

13

Keyword: DesignDay

Purpose: the DesignDay input syntax defines a single day of weather information

Design day simulations are often used for peak load or sizing calculations

Data required for this keyword can be found in a variety of places (see next slide)

14

DesignDay Sources

MacroDataSets folder US, Canada, and International 2001 ASHRAE data

Datasets US locations pre-1997 ASHRAE data, from BLAST library

*.ddy files Included in weather data zip files on web site 2001 ASHRAE data

15

Keyword: DesignDay

IDD Description (detailed) DesignDay, \min-fields 14 A1 , \field DesignDayName \type alpha \required-field \reference DesignDays N1 , \field Maximum Dry-Bulb Temperature \required-field \units C \minimum> -70 \maximum< 70 \note \type real

Keywordnote all one word

14 fields (all) required

Unique character string name for design day

Other references to a design day in the IDF will expect an existing design day name

N1 is the maximum dry bulb temperature experience for this design day in degrees Celsius

16

Keyword: DesignDay

IDD Description (detailed) N2 , \field Daily Temperature Range \required-field \units deltaC \minimum 0 \type real \note must still produce appropriate maximum dry bulb N3 , \field Wet-Bulb Temperature At MaxTemp \required-field \units C \minimum> -70 \maximum< 70 \type real

Range of temperatures expected

Units are C Must be zero or greater

Mean coincident wet-bulb temperature in C

17

Keyword: DesignDay

IDD Description (detailed) N4 , \field Barometric Pressure \required-field \units Pa \minimum> 70000 \maximum< 120000 \type real \ip-units inHg N5 , \field Wind Speed \required-field \units m/s \minimum 0 \maximum 40 \ip-units miles/hr \type real

Outdoor barometric pressure (assumed constant for entire day) in Pascals

IP Units if interface accepts these units

Wind speed (assumed constant for entire day) in meters per second

18

Keyword: DesignDay

IDD Description (detailed) N6 , \field Wind Direction \required-field \units deg \minimum 0 \maximum 359.9 \note North=0.0 East=90.0 \type real N7 , \field Sky Clearness \required-field \minimum 0.0 \maximum 1.2 \default 0.0 \note 0.0 is totally unclear, 1.0 is totally clear \type real

Wind direction (assumed constant for entire day) in degrees (assumes North is 0, East is 90, South is 180, etc.)

Sky clearness (assumed constant for entire day) Maximum allows for altitude adjustment

19

Keyword: DesignDay

IDD Description (detailed) N8 , \field Rain Indicator \minimum 0 \maximum 1 \default 0 \note 1 is raining, 0 is not \type integer N9 , \field Snow Indicator \minimum 0 \maximum 1 \default 0 \note 1 is Snow on Ground, 0 is no Snow on Ground \type integer

Rain flag (assumed constant for entire day) affects exterior convection coefficients

Rain flag (assumed constant for entire day) affects ground reflectance

Should be an integer value not a decimal number

20

Keyword: DesignDay

IDD Description (detailed) N10, \field Day Of Month \required-field \minimum 1 \maximum 31 \type integer \note must be valid for Month field N11, \field Month \required-field \minimum 1 \maximum 12 \type integer

Numerical day of month (must be valid for month chosen)

Numerical month of the year

21

Keyword: DesignDay

IDD Description (detailed) A2 , \field Day Type \required-field \note Day Type selects the schedules appropriate \note for this design day \type choice \key Sunday \key Monday \key Tuesday \key Wednesday \key Thursday \key Friday \key Saturday \key Holiday \key SummerDesignDay \key WinterDesignDay \key CustomDay1 \key CustomDay2

Type of day/day of the week for design day (may affect schedule values)

This field must equal one of these choices of keywords (note that none of these keywords has spaces)

This field is a choice of one of the options listed as \key

22

Keyword: DesignDay

IDD Description (detailed) N12; \field Daylight Saving Time Indicator \minimum 0 \maximum 1 \default 0 \note 1=Yes, 0=No \type integer

Whether daylight savings time should be in effect for this design day

23

Keyword Example: DesignDay

IDF Example DesignDay, DENVER COLORADO SUMMER, !- DesignDayName 32.8, !- Maximum Dry-Bulb Temperature {C} 17.8, !- Daily Temperature Range {C} 15.0, !- Wet-Bulb Temperature At MaxTemp {C} 84060.0, !- Barometric Pressure {Pa} 3.97, !- Wind Speed {m/s} 146.0, !- Wind Direction {deg} 1.10, !- Sky Clearness 0, !- Rain Indicator 0, !- Snow Indicator 21, !- Day Of Month 7, !- Month Monday, !- Day Type 0; !- Daylight Saving Time Indicator

24

Keyword: DaylightSavingPeriod


Purpose: define the time frame during which daylight savings rules should apply

Note that this can be specific to location (not all sites use daylight savings time in the summer)

DaylightSavingPeriod, A1, \field StartDate A2; \field EndDate

25


IDD Description (detailed) DaylightSavingPeriod, \unique-object \min-fields 2 \memo This object sets up the daylight saving period \memo for any RunPeriod. \memo Ignores any daylightsavingperiod values on the \memo weather file and uses this definition. \memo (These are not used with DesignDay objects.) A1, \field StartDate \required-field


Note: not used for design days and will override any information found on the weather file Date when daylight savings goes into effect

(details on format on next slide)

26


IDD Description (detailed) A2; \field EndDate \required-field \memo Dates can be several formats: \memo / (month/day) \memo \memo \memo in

27

Keyword Example: DaylightSavingPeriod

IDF Examples

or

DaylightSavingPeriod, 1st Sunday in April, !- Start Date Last Sunday in October; !- End Date

DaylightSavingPeriod, 4/1, !- Start Date 31 October; !- End Date

28

Keyword: SpecialDayPeriod


Purpose: to set up the occurrence of special days throughout the year or to override the values set in a weather file

Note: this information does not apply to design days

SpecialDayPeriod, A1, \field Holiday Name A2, \field StartDate N1, \field duration (number of days) A3; \field SpecialDayType

29


IDD Description (detailed) SpecialDayPeriod, \min-fields 4 \memo This object sets up holidays/special days to be \memo used during weather file run periods. \memo (These are not used with DesignDay objects.) \memo Depending on the value in the run period, days \memo on the weather file may also be used. However, \memo the weather file specification will take \memo precedence over any specification shown here. \memo (No error message on duplicate days or \memo overlapping days). A1, \field Holiday Name \required-field


Unique identifying name

30


IDD Description (detailed) A2, \field StartDate \required-field \memo Dates can be several formats: \memo / (month/day) \memo \memo \memo in

31


IDD Description (detailed) A3; \field SpecialDayType \required-field \note SpecialDayType selects the schedules \note appropriate for each day so labeled \type choice \key Holiday \key SummerDesignDay \key WinterDesignDay \key CustomDay1 \key CustomDay2 \default Holiday

Type of day (see choices given in the \key list) this should be considered

Note the impact on schedules

32

Keyword Example: SpecialDayPeriod

IDF Example SpecialDayPeriod, Memorial Day, !- Holiday Name Last Monday in May, !- Start Date 1, !- duration (number of days) Holiday; !- SpecialDayType

33

Keyword: RunPeriod


Purpose: to define the simulation period for EnergyPlus (program does not assume entire year simulation)

RunPeriod, N1 , \field Begin Month N2 , \field Begin Day Of Month N3 , \field End Month N4 , \field End Day Of Month A1 , \field Day Of Week For Start Day A2, \field Use WeatherFile Holidays/Special Days A3, \field Use WeatherFile DaylightSavingPeriod A4, \field Apply Weekend Holiday Rule A5, \field Use WeatherFile Rain Indicators A6; \field Use WeatherFile Snow Indicators

34

Keyword: RunPeriod

IDD Description (detailed) RunPeriod, \min-fields 10 N1 , \field Begin Month \required-field \minimum 1 \maximum 12 \type integer N2 , \field Begin Day Of Month \required-field \minimum 1 \maximum 31 \type integer


Starting date for period to be simulated; entered as two separate fields, both integer values

35

Keyword: RunPeriod

IDD Description (detailed, continued) N3 , \field End Month \required-field \minimum 1 \maximum 12 \type integer N4 , \field End Day Of Month \required-field \minimum 1 \maximum 31 \type integer

Ending date for period to be simulated; entered as two separate fields, both integer values

36

Keyword: RunPeriod

IDD Description (detailed, continued) A1 , \field Day Of Week For Start Day \note = \default UseWeatherFile \type choice \key Sunday \key Monday \key Tuesday \key Wednesday \key Thursday \key Friday \key Saturday \key UseWeatherFile

Day of week for starting date; can be used to override day of week specified on the weather file

Options for day of week for starting date

Note that this is not a required field due to the lack of the line that says \required-field; all fields after this point are also optional

37

Keyword: RunPeriod

IDD Description (detailed, continued) A2, \field Use WeatherFile Holidays/Special Days \note If yes or blank, use holidays on Weatherfile. \note If no, do not use the holidays on Weatherfile. \note Note: You can still specify holidays/special days \note using the SpecialDayPeriod object(s). \type choice \default Yes \key Yes \key No A3, \field Use WeatherFile DaylightSavingPeriod \note If yes or blank, use period specified on Weatherfile. \note If no, do not use period as specified on Weatherfile. \type choice \default Yes \key Yes \key No

These two input fields are used to override the definition of holidays and daylight savings time period from the weather file.

The choices for these fields are simply a yes or a no.

38

Keyword: RunPeriod

IDD Description (detailed, continued) A4, \field Apply Weekend Holiday Rule \note if yes and single day holiday falls on weekend, \note "holiday" occurs on following Monday \type choice \key Yes \key No \default No A5, \field Use WeatherFile Rain Indicators \type choice \key Yes \key No \default Yes A6; \field Use WeatherFile Snow Indicators \type choice \key Yes \key No \default Yes

These three input fields are used to override the definition of holiday weekend rules, presence of rain indicators, and presence of snow indicators from the weather file.

The choices for these fields are simply a yes or a no.

39

Keyword Example: RunPeriod

IDF Example

or

RunPeriod, 1, !- Begin Month 1, !- Begin Day Of Month 3, !- End Month 31; !- End Day Of Month

RunPeriod, 1, !- Begin Month 1, !- Begin Day Of Month 3, !- End Month 31, !- End Day Of Month Tuesday, !- Day of Week for Start Day Yes, Yes, Yes, Yes, Yes; !- Special Weather File Flags

40

Keyword: Run Control


Purpose: overall control of what the user wants EnergyPlus to simulate (design days and/or weather file runs, perform auto-sizing)

RUN CONTROL, A1, \field Do the zone sizing calculation A2, \field Do the system sizing calculation A3, \field Do the plant sizing calculation A4, \field Do the design day simulations A5; \field Do the weather file simulation

41


IDD Description (detailed) RUN CONTROL, \unique-object A1, \field Do the zone sizing calculation \type choice \key Yes \key No \default No A2, \field Do the system sizing calculation \type choice \key Yes \key No \default No A3, \field Do the plant sizing calculation \type choice \key Yes \key No \default No

Keywordnote that there IS a space between the two words

These will be discussed later in the semester

42


IDD Description (detailed, continued) A4, \field Do the design day simulations \type choice \key Yes \key No \default Yes A5; \field Do the weather file simulation \type choice \key Yes \key No \default Yes

Fields define whether or not to simulate design days (defined by the DesignDay input line) or an attached weather file (see RunPeriod input line)

Choices for both fields are simply yes or no

43

Keyword Example: Run Control

IDF Example or

RUN CONTROL, No, No, No, No, Yes;

RUN CONTROL, No, !- Do the zone sizing calculation No, !- Do the system sizing calculation No, !- Do the plant sizing calculation No, !- Do the design day simulations Yes; !- Do the weather file simulation

44

Keyword: GroundTemperatures


Purpose: to set the ground temperatures experienced at the building location (impact on places where the ground is in contact with the building)

GroundTemperatures, N1 , \field January Ground Temperature N2 , \field February Ground Temperature N3 , \field March Ground Temperature . . . etc . . . N12; \field December Ground Temperature

45

Keyword: GroundTemperatures

IDD Description (detailed) GroundTemperatures, \unique-object \min-fields 12 N1 , \field January Ground Temperature \required-field \units C \type real \default 13


12 values, one per month

Repeated for each month of the year

Temperatures in Celsius; note that these are temperatures at the outside surface not deep ground temperatures

46

Keyword Example: GroundTemperatures

GroundTemperatures, 20.03, !- January Ground Temperature {C} 20.03, !- February Ground Temperature {C} 20.13, !- March Ground Temperature {C} 20.30, !- April Ground Temperature {C} 20.43, !- May Ground Temperature {C} 20.52, !- June Ground Temperature {C} 20.62, !- July Ground Temperature {C} 20.77, !- August Ground Temperature {C} 20.78, !- September Ground Temperature {C} 20.55, !- October Ground Temperature {C} 20.44, !- November Ground Temperature {C} 20.20; !- December Ground Temperature {C}

IDF Example or

GroundTemperatures, 20.03, 20.03, 20.13, 20.30, 20.43, 20.52, 20.62, 20.77, 20.78, 20.55, 20.44, 20.20;

47

Keyword: GroundReflectances


Purpose: to set the reflectance of the ground surrounding the building (affects radiation incident on building surfaces)

GroundReflectances, N1 , \field January Ground Reflectance N2 , \field February Ground Reflectance N3 , \field March Ground Reflectance . . . etc . . . N12; \field December Ground Reflectance

48

Keyword: GroundReflectances

IDD Description (detailed) GroundReflectances, \unique-object \min-fields 12 N1 , \field January Ground Reflectance \default 0.2 \type real \minimum 0.0 \maximum 1.0 \units dimensionless


12 values, one per month

Repeated for each month of the year

Note: values for reflectance are highly dependent on the type of ground cover around the buildinggrass, dirt, concrete, asphalt, etc.

49

Keyword Example: GroundReflectances

IDF Example or

GroundReflectances, 0.2, !- January Ground Reflectance 0.2, !- February Ground Reflectance 0.2, !- March Ground Reflectance 0.2, !- April Ground Reflectance 0.2, !- May Ground Reflectance 0.2, !- June Ground Reflectance 0.2, !- July Ground Reflectance 0.2, !- August Ground Reflectance 0.2, !- September Ground Reflectance 0.2, !- October Ground Reflectance 0.2, !- November Ground Reflectance 0.2; !- December Ground Reflectance

GroundReflectances, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2;

50

Keyword: Snow Ground Reflectance Modifiers


Purpose: to account for the presence of snow and how that impacts the ground reflectance (weather files will indicate whether or not there is snow on the ground)

Snow Ground Reflectance Modifiers, N1, \field Ground Reflected Solar Modifier \minimum 0.0 \default 1.0 N2; \field Daylighting Ground Reflected Solar Modifier \minimum 0.0 \default 1.0

51


IDD Description (detailed) Snow Ground Reflectance Modifiers, N1, \field Ground Reflected Solar Modifier \minimum 0.0 \default 1.0 \note Value for modifying the "normal" ground reflectance \note when Snow is on ground when calculating the \note "Ground Reflected Solar Radiation Value a value of \note 1.0 here uses the "normal" ground reflectance \note Ground Reflected Solar = (BeamSolar*CosSunZenith \note + DiffuseSolar)*GroundReflectance \note This would be further modified by the Snow Ground \note Reflectance Modifier when Snow was on the ground \note When Snow on ground, effective GroundReflectance is \note GroundReflectance*"Ground Reflectance Snow Modifier" \note Ground Reflectance achieved in this manner will be \note restricted to [0.0,1.0]

52


IDD Description (detailed) N2; \field Daylighting Ground Reflected Solar Modifier \minimum 0.0 \default 1.0 \note Value for modifying the "normal daylighting \note ground reflectance when Snow is on ground \note When calculating the "Ground Reflected Solar \note Radiation Value a value of 1.0 here uses the \note normal ground reflectance \note Ground Reflected Solar = (BeamSolar*CosSunZenith \note + DiffuseSolar)*GroundReflectance \note This would be further modified by the Snow Ground \note Reflectance Modifier when Snow was on the ground \note When Snow on ground, effective GroundReflectance is \note GroundReflectance*"Ground Reflectance Snow Modifier" \note Ground Reflectance achieved in this manner will be \note restricted to [0.0,1.0]

53

Keyword Example: Snow Ground Reflectance Modifiers

IDF Example or Snow Ground Reflectance Modifiers, 1.5, !- Ground Reflected Solar Modifier 2.0; !- Daylighting Ground Reflected Solar Modifier

Snow Ground Reflectance Modifiers, 1.5, 2.0;

54

Summary

Location and exterior thermal environment play a critical role in determine the thermal loads/energy consumption of a building

Many input keywords in EnergyPlus control what is being simulated For example: Version, Run Control, Location,

DesignDay, SpecialDayPeriod, RunPeriod, DaylightSavingPeriod, GroundTemperature, GroundReflectance, Snow Ground Reflectance Modifiers

EnergyPlus flexibility also results in user responsibility (having to define various parameters in the input file)

Lecture 5: Building Envelope Description (Part I)



2


Every building is different in many ways: Location/exterior environment Construction/building envelope HVAC system

Building envelope/construction determines how a building will respond to the exterior environment

Thermal simulation requires information about the physical make-up of the building, where various constructions are located and how they are oriented, how the building is subdivided into zones, etc.

Thermal simulation requires information on the building envelope to properly analyze the building from an energy perspective

3


Gain an understanding of how to specify the building construction Groups of Surfaces (Zones) and Overall

Building Characteristics Walls, Roofs, Ceilings, Floors, Partitions,

etc. Materials and Groups of Materials

(Constructions)

4

Keywords Covered in this and next Lecture

Building Zone SurfaceGeometry Surface (all types) Construction Material:Regular Material:Regular-R Material:Air

5

Definitions and Connections

Building: Entire collection of interior and exterior features of

the structure Buildings may consist of one or more zones

Zones: Group of surfaces that can interact with each

other thermally and have a common air mass at roughly the same temperature

One or more rooms within a building Zones may consist of one or more surfaces

6

Definitions and Connections (contd)

Surfaces: Walls, Roofs, Ceilings, Floors, Partitions, Windows, Shading

Devices One or more surfaces make up a zone Surfaces consist of a series of materials called a

construction

Construction: Group of homogeneous one-dimensional material layers Each surface must have a single construction definition Each construction is made up of one or more materials

7

Definitions and Connections (continued)

Materials: Define the thermal properties for layers

that are used to put together a construction

One or more material layers make a construction

8

Envelope Hierarchy

Building

Zone Zone Zone more zones

Surface Surface Surface Surface more surfaces

Construction

Material Material Material Material more materials

only one construction per surface

9

More on Zones

Thermal zone definition very generic and does not answer the following questions: How many surfaces to a zone? How many zones should be defined for a

particular building? Should each room be a zone? Can the entire building be a zone?

10

Defining Thermal Zones by Objective

Objectives of a study can dictate the size and number of thermal zones Air flow study: sizing fans and ducts Several rooms per zone Zone per system type

Block loads or central plant study: sizing of heating and cooling producers Minimize number of zones (maybe only 1)

11

Ft. Monmouth Education Center

12

Defining Thermal Zones by Design Conditions

T test: if there is an air temperature difference between adjacent spaces, separate thermal zones are needed Might also be seen in different control

types

13

Defining Thermal Zones by Design Conditions (contd)

Space usage/internal gains test: Differences in internal gains may result in

different conditioning requirements or distribution Office vs. gymnasium

Space usage differences may alter the ventilation or exhaust requirements of a space Office vs. kitchen vs. chemistry laboratory

14

Defining Thermal Zones by Design Conditions (contd)

Environmental conditions test: exposure to different thermal surroundings/quantifying the effect Different space orientationssolar gains Exposure to the ground Exposure to the outdoor environment

15

Ft. Monmouth Education Center

T test: loading dock

Space use: kitchen, dining area

Outdoor exposure: west wing solar

16

Loads Features and Capabilities

How does EnergyPlus calculate what it will take to keep a zone at the desired thermal conditions? EnergyPlus contains the heat balance engine from

IBLAST, a research version of BLAST with integrated loads and HVAC calculation. The major enhancements of the IBLAST heat balance

engine include mass transfer and radiant heating and cooling

Essentially identical in functionality to the Loads Toolkit developed under ASHRAE Research Project (RP-987)

17

Loads Features and Capabilities (contd)

Heat balance engine models room air as well-stirred with uniform temperature throughout.

Room surfaces are assumed to have: Uniform surface temperatures Uniform long and short wave irradiation Diffuse radiating and reflecting surfaces Internal heat conduction

18

EnergyPlus Model For Building Loads

Heat Transfer (Diffusion and Storage)

Internal Radiation

Tair

Solar Beam

Infiltration (Sensible & Latent)

Diffuse Solar

Reflected Solar

Internal Radiation Convection

Conditioned Air

Return Air

Heat & Moisture

Source (People & Equipment)

19

Equipment & People Loads

EquipmentOccupant

energyplus university course

Documents

course introduction

course syllabus

course syllabi

course evaluations

energyplus program

minute class periods

usage of energyplus

computer laboratories