energy modeling training: introduction to openstudio · pdf fileenergy modeling training:...

Energy Modeling Training: Introduction to OpenStudio/E+

Yung Nguyen, EIT, BEMP, CEM

Celia King-Scott, PE, BEMP

Learning Objectives

• Understand where and how energy modeling is used

• Be able to run a simple model created from OpenStudio

• Have a basic understanding of work flow • Have an understanding of energy model

output

Module of the Day

• Introduction to Energy Modeling & Software • Workflow within OpenStudio & EnergyPlus Break • Model Practice 1: Templates • Model Practice 2: Geometry • LUNCH • Model Practice 3: Assign Attributes • Model Practice 4: HVAC Systems & Simulations Break • EnergyPlus Interface • Reporting & Self-Check

Introduction: What is an Energy Model? A computer simulation that calculates the energy usage of a building based on the principle of building science and vast amount of data inputs.

Thermal mass properties of walls, roof, floor, slab, interior walls

Thermal properties of windows, shading coefficient

Lighting intensities, heat emitted by lighting, cooling needed to offset the heat emitted

Plug load intensity per area type, plug load radiation fraction

Heating & Cooling: equipment size, part performance curve, fan size, fan performance curve, coil types, plant type, static pressure loss, control strategies including: outdoor reset, demand matching, demand control ventilation, etc.

Indoor Air Requirement: room types, air changes required

Space types, area, height, ceiling height/ plenum

Introduction: Why Do You Need a Model? • Interactive effects – modeling whole buildings

taking account of how a reduction in an end use would affect another end use.

• Example: What happens when you reduce the lighting load by 50%? What end uses are affected?

Introduction: When Do You Use a Model?

NEW CONSTRUCTION EXISTING BUILDINGS

NEW CONSTRUCTION EXISTING BUILDINGS

• To establish cost/benefits for design decision in high performance buildings

• Understand integration of complex systems

• Establish energy budgets for operation

• Permitting/LEED

• New Construction Whole Building Design Incentive

• To determine savings, cost, and benefits based on changing operation strategies

• Often used in major capital projects to determine the best life cycle cost options

• Used in Retro-commissioning, Monitoring Based Commissioning, ASHRAE Level 3 Audits, etc.

• Help facilities manager determine the ROI and plan projects internally

Introduction: When Do You Use a Model?

NEW CONSTRUCTION

Introduction: When Do You Use a Model?

Introduction: How Do You Model? • Evaluate the software of choice • Taking this training • Practice, practice, practice • Know what to look for • Become a master modeler!

Introduction: Software History

• DOE-2 engine was a plain program used to analyze energy usage. DOE-2 later supports eQuest, the graphic user interface.

• DOE stops supporting DOE-2 development and switches gears to EnergyPlus engine (meant to unite BLAST and DOE-2 best features together).

• Note: There’s a difference between ENGINE and

SOFTWARE INTERFACE (GUI).

Introduction: The Future

Introduction: Software Market

3D+

RES NON-RES

Introduction: Software Market

3D+

FREE NOT FREE

Introduction: Software Market

3D+

FORUM PAID TECH SUPPORT

Introduction: What is EnergyPlus?

IDF EDITOR

E+ ENGINE

INPUT

Input Data

Project.idf

Weather

File

Introduction: How Do You Work in E+?

NOTEPAD

IDF EDITOR

Introduction: EPlus Engine & GUIs

ENERGYPLUS is an ENGINE

NREL Developed

GUI for EnergyPlus

GUI for E+

California Compliance Software

Run on E+

THESE ARE THE GUIS

NotePad or IDF Editor

Introduction: Why OpenStudio?

vs

DRAG & DROP TEXT

Introduction: Why OpenStudio/ E+? • Capabilities Highlight

– Abilities to model many HVAC systems

– Data output for many variables at any intervals (cd vs hard drive)

– Special systems (refrigeration, electro chromatic windows)

– OpenStudio measures (automation of energy modeling tasks)

• Limitations – Rely on Unmet Hours Forum

– Very high learning curve for beginner

– Requires high troubleshooting skills

– Does not have component module offered by other software

– Long run time depend on model complexities

Icebreaker

Workflow: Building the Model

OpenStudio

MEASURES SKETCHUP

IDF Editor NOTEPAD

Workflow: Programs Set Up Time

OpenStudio

MEASURES SKETCHUP

MAKE 2017

IDF Editor NOTEPAD

OS 2.1.0

EnergyPlus v8.7

Workflow: Programs Set Up Time

Workflow: Tips & Tricks

1. Always save different versions 2. You may want to name your surfaces and

sub-surfaces (walls & windows) 3. Google your errors / Unmet Load Hours

Forum 4. Practice. Practice. Practice.

Workflow: OpenStudio Interface

REF: http://nrel.github.io/OpenStudio-user-documentation/img/pdfs/openstudio_interface_quickstart.pdf

Workflow: OpenStudio Interface

REF: http://nrel.github.io/OpenStudio-user-documentation/img/pdfs/openstudio_interface_quickstart.pdf

Workflow: OpenStudio Interface

REF: http://nrel.github.io/OpenStudio-user-documentation/img/pdfs/openstudio_interface_quickstart.pdf

Workflow: OpenStudio Interface

REF: http://nrel.github.io/OpenStudio-user-documentation/img/pdfs/openstudio_interface_quickstart.pdf

Workflow: Building the Model

OpenStudio

MEASURES SKETCHUP

IDF Editor NOTEPAD

1 WAY STREET

2 WAYS STREET

ADVANCE

BREAK

Practice Model Workflow

1. Make templates

2. Build geometry

3. Add refinements

4. Last resort

Practice 1: Templates

• OpenStudio uses templates for different building types. When you build geometry, you apply the space to a template as you go, so that if you need to change something later on, it can do a global change all at once.

• Approach to building model is SYSTEMATIC.

Practice 1: Templates Open OpenStudio. Go to File > Load Library

This will load ASHRAE 90.1 profiles and other standards’ general assumptions.

Practice 1: Construction Template

Materials •Insulation •Layers •Gypsum

Construction •Exterior Wall 1

•Roof Assembly 2

Construction Set

• Roof + Walls + Windows + All Other Surface

• Need Thermal Properties of Layer

• Need Assembly Properties

• Combination of Assembly

Practice 1: Construction Template

1. Materials – R30 Insulation

2. Construction Assembly

Practice 1: Construction Template 3. Construction Set

Practice 1: Schedule Template

Schedule •Design Days •Run Profile Priority / Default

•% , Fractional

Schedule Set

• People + Lighting + Operation Schedule + More

• Combination of Schedule

Practice 1: Schedule Template

Practice 1: Schedule Template

Practice 1: Internal Gains

Typical important ones Plug load is not really regulated, but there are typical values / reasonable assumptions suggested from ASHRAE 90.1 User Manual or other guiding documentation based on space types

Practice 1: Space Type Template

Template inception: Templates within a template.

Practice 1: Space Type Template

Template inception: Templates within a template.

Systems

Thermal Zones

Space Types

Schedule / Construction

/ Internal Gains

Practice 1*: Thermal Zone

Best Practices Tip •Thermal zones should follow HVAC Designer rule of thumb •Perimeter Zones and Interior Zones •Drastic different room loads will have different HVAC needs – separate them •Group similar zones and equipment together

BREAK

Practice 2: Geometry

30’

15’

10’

10’

10’

5’

5’

5’ 25’

Zone 1 Office

Zone 2 Office

Zone 3 Reception Zone 4

Corridor

Zone 5 Conference

30’

1st Floor 2nd Floor

North & South East & West

18’

4’ 6’

6’

4’ 2’ 4’ 2’ 2’

1st Floor

North & South 2nd Floor

18’

4’ 6’

2’

East & West

6’

4’ 7’ 2’

Practice 2: Geometry

Practice 2: Geometry

1

2 Double Click

3 Draw

4 Extrude OR

METHOD 1: Create Space by Hand

Practice 2: Geometry Useful default shortcuts in SketchUp:

P H

Space L M

Extrude Hand Select Line (Draw Pencil) Move

Practice 2: Geometry

METHOD 2: Create Space by “Create Spaces from Diagram”

1 Draw

2 Create Spaces from Diagram

Practice 2: Geometry

Practice 2: Geometry

Boundary Conditions Tan – Ground Blue - Air

Constructions Tan – Walls Red – Roof Transparent Blue - Windows

By Space By Thermal Zones By Construction

Example Practice 2: Geometry

Launch OS

Show Errors

Filter

Inspector

Create Spaces from Diagram

Attributes To Space

Surface Matching

Create Space

Most Useful Icons

Practice 2: Geometry Surface Matching & Intersect

• OpenStudio requires adjacent surfaces to have EXACT same area.

• Match and Intersect tool draws new geometry (for more complicated shapes).

LUNCH BREAK

Practice 3: Assign Attributes Definitions to Templates

Practice 3: Assign Attributes

Practice 3: Assign Attributes

• Inspector Tool • Can assign name, space type,

construction template, schedule template, thermal zone

• Can only edit one object at a time even if you select multiple objects

• Filter Tool • Can filter out 3D components with

criteria

Icebreaker

Practice 4: HVAC System

Zone 1 Office

Zone 2 Office

Zone 3 Reception Zone 4

Corridor

Zone 5 Conference

AC-1 AC-2

AC-3 AC-4

Packaged Rooftop Units • 3.5 COP • Economizer Dry Bulb

Practice 4: HVAC System

1. Assign Set Point in Thermal Template

2. Create Air-loop System

Practice 4: Before Simulation Download weather file from: https://energyplus.net/weather-region/north_and_central_america_wmo_region_4/USA/AZ

Phoenix (TMY3) •epw – Annual Weather Data •ddy – Design Day Data (for sizing)

Practice 4: Before Simulation

Practice 4: Simulate!

BREAK

When Export to EnergyPlus…

• It’s a one way street. Not easy going to back to OpenStudio.

• Only export to E+ to use the EnergyPlus Energy Management System (EMS) or things OpenStudio can’t do.

EnergyPlus Interface

Find and launch the program EP-launch.exe located in the main EnergyPlus directory Usually C:\EnergyPlusVXXX

EnergyPlus Interface

.IDF Input File

.epw Weather File

EnergyPlus Interface

• Click the ‘Simulate’ button to begin running the simulation

• EnergyPlus should appear in an MS-DOS window

EnergyPlus Interface

• ALWAYS look at the ERR file when the simulation has completed successfully!

• There are warnings that can help you troubleshoot results and are important to address!

Software reports: Parallel OPENSTUDIO ENERGYPLUS

Annual & Monthly Overview Annual Building Utility Performance Summary (ABUPS)

Air & Plant Loops Detail System Summary (shows unmet hour load)

Site and Source Summary Energy Cost by Fuel Source

HVAC Load Profiles Equipment Summary System Summary

Envelope Envelope Summary

Software Reports: Good & Bad OPENSTUDIO ENERGYPLUS

Nice graphs / visually pleasing Highly detailed, know the autosize values & user inputs values

Summarize key facts Harder to Navigate / Hunt Information

Lack details for a deep review Excel Friendly

Less friendly to export Map-able to custom reports

Overall useful for quick QC Overall useful for detailed QC

Self-Check Tips

• Organize your zones / system early on will serve you well

• Reduce # of spaces / surface areas for run time

• “All models are false, but some are useful” • Benchmark to see if your performance is in

the right ballpark • Refer to Unmet Load Hour forums for

questions or join your local energy modeling club

Self-Check Tips

• Verify that rule of thumb expectations • Take into account the differences in heating

and cooling loads between the baseline and proposed, based on implemented EEMs: – Increased insulation – High performance fenestration/shading – Thermal mass – Building Orientation

Self-Check Tips • Verify where the savings are coming from, i.e., which end-

use(s) has the greatest reduction in energy consumption • Focus on elements where energy savings don’t appear to be

justified • What end-use consumption holds more weight as far as %

of total consumption?

Key Takeaways

Learning Objectives: • Understand where and how energy modeling

are used

• Be able to run simple model created from OpenStudio

• Have a basic understanding of workflow

• Have an understanding of energy model output

Key Takeaways

• When you see the same error over and over again with over a thousand variables to change… chances are it’s somewhere in HVAC and secondly, keep sane by taking a walk.

THANK YOU!