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2011 Results Presentation 11 September 2011 ASHRAE Standard 90.1 and Building Energy Simulation

- Key concepts of building energy simulation

- Building energy software

Dr. JIANG Wei, LEED AP, BEAM Pro 14 June 2012

1

1. Fundamentals of Building Energy Simulation

2. Best Practices for High Quality Building Energy Simulation

3. Modeling to Inform Design

4. A Guide to Energy Simulation Software

5. Energy Simulation for BEAM Plus and LEED Certification

6. Available Resources

Introduction

2

2011 Results Presentation 11 September 2011

3

Fundamentals of Building Energy Simulation

Building Modeling

Source: Godfried Augenbroe, 2010. Energy Modeling and Simulation.

To use a (computer) model (= virtual building) to predict

what will happen in the real world 4

Buildings is a Complex Thermodynamic Object

Source: Hui, S, 2011. MEBS6016 Energy Performance of Buildings

5

What is Energy Simulation?

Also called as “Energy Modeling”, “Energy Analysis”

Simple definition - creating a computer model of a building and its systems to predict annual energy consumption

6

2

Building Energy Simulation is Used for

月耗电费用比较

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

RM

B 设计模型

节能模型

ASHRAE基准模型

Building energy performance and energy cost evaluation

Performance verification: compare performance of a proposed design to a particular standard (EMSD PBEC, ASHRAE 90.1)

Decision making and design optimization：comparing design alternatives

Energy conservation measures evaluation (i.e. payback)

Green building certification (BEAM Plus, LEED® ) – driver for fast growing group of energy modelers

Tax credits requirements (US Revenue Service (IRS) Code 179D Tax Credits)

7

Four Main Modules

Building Loads

Solar gains

Heat Transfer through envelope

Heat from people , lights and internal equipment

Infiltration, fresh air

Interaction of the building with its climate

HVAC Systems

Simulates interaction of equipment with loads

Source: Hensen et. al. 2004. Building performance simulation for better design: some issues and solutions.

The 21th Conference on Passive and Low Energy Architecture. Eindhoven, The Netherlands, 19 – 22 September 2004.

Plant

Primary equipment (chillers, boilers, heat exchangers, etc.)

Economics

Utility rate structures Life cycle analysis

8

Energy Simulation vs. HVAC Sizing

Sizing programs are primarily designed to calculate peak demand/loads during the heating and cooling seasons. Almost all buildings of any complexity have a sizing analysis of some kind run by a design engineer, or mechanical contractor.

Energy programs are primarily designed to predict the annual energy consumed by a building in terms of energy, cost or carbon emission. These tools are normally run by an energy engineer.

Energy simulation typically includes equipment sizing, and most energy simulation software can handle both tasks.

Source: http://wbdg.org/resources/energyanalysis.php?r=secondary

9

Energy Simulation Tools

Simple / manual methods

Analytical methods (spreadsheet bin analysis etc.)

Single evaluation use / specialized tools

Complex integrated tools

Computer-based

Consists of four main modules: Loads, Systems, Plants,

Economics

Performs hourly simulations to predict annual energy use of a

building

The best way to assess the interactions among various building

components

10

Modeling Process

Weather data

Building geometry

Construction type

Occupancy

Lighting

Equipment

HVAC System

Plant

Economics Info

Load

System

Plant

Economics

Space conditions

Heating and cooling loads

System energy

Plant energy

Energy cost

Lo

ad

s n

ot

me

t

Lo

ad

s n

ot

me

t

Inte

rac

tio

n

BUILD A MODEL RUN A SIMULATION ANALYZE RESULTS

11

Build A Model

Input geometry

(CAD data) Determine space

classification Define

thermal blocks

Input zone properties

(construction, temp, RH,

internal heat gains)

Assign HVAC systems to

thermal zones

Create plants Input

economics/carbon

information 12

3

13

Model Geometry

Rules of Thumb For Simplification

Simplify

REALITY ENERGY MODEL

14

Model Geometry (Cont’d)

Thermodynamically, only (3) things matter for modeling heat transfer Surfaces Area Orientation Tilt

Total volume matters IF infiltration is specified in ACH

SketchUp Plugins

• Open Studio for EnergyPlus

• IES Virtual Environment

CAD (dwg files)

• 2-D CAD plans may be imported into energy modeling programs

• gbXML streamlines the transfer of building information to and from engineering models

15

Model Geometry (Cont’d) Modeling Geometry Data Hierarchy

Site

Building a

Block a

Zone a Zone b

Surface a Surface b

Opening a Opening b

Block b

Zone c Zone d

Surface c Surface d

Opening c Opening d

Source: Diego Ibarra and Christoph Reinhart, DesignBuilder / EnergyPlus ‘Tutorial #1’ Getting Started, 2009

16

Define Thermal Block

Thermal Block --- A collection of one or more HVAC zones grouped together for simulation purposed. Spaces need not be contiguous to combined within a single thermal block.

Concepts

Required engineering judgment

Simplified model without compromising accuracy – shortened simulation

time

Combine thermally similar zones into a single block

Similar load density

Similar time-dependent

thermal behavior

Source: Energy Modeling for the LEED® Energy & Atmosphere Credit 1, Carrier Corp.

17

Number of zones is proportional to

complexity of energy model

Aggregation of rooms into zones: significant impact on energy use

and overheat prediction

Especially with large multi-zone

systems

Zoning in simulation models

can differ from actual HVAC

zoning

# of model zones < # of HVAC

zones

Energy model zones are abstract

18

Define Thermal Block (Cont’d)

4

Usage • All rooms should have similar internal loads and usage

schedules

Temperature Control • All rooms should have the same Tstat schedules Solar Gains • Perimeter zones with windows: Min. one zone for each

compass direction

• Unglazed exterior zones can be combined

• Consider shading! Perimeter or Interior Location • 3.5~4.5m perimeter zones often require winter heating

• Core spaces can require year round cooling

Distribution System Type • Combine rooms served by the same type of distribution

system (i.e. fan coil units) 19


Energy Modeling

Typical one zone for each space

Hourly loads are calculated based on an energy balance of the space.

At the thermal zone level, the loads from the spaces are considered in

conjunction with the temperature set-point and HVAC operating schedules to

determine the zone load.

Thermal Zone = area controlled by

a single thermostat

20


Conditioned

• Space is heated or cooled

Unconditioned

• Space is neither heated nor cooled

• Examples are false ceiling spaces not used as return air plenums, attics, crawl spaces and garages

Plenum

• Return air space

• Atrium as return plenum

• Heat transfer within plenums

21

Define Thermal Block (Cont’d) General Rules for Defining Thermal Block

Separate thermal blocks should be created for:

Zones with different space uses and functions

Perimeter and interior spaces (rule of thumb for open plan: 4~5m from exterior wall)

Corner zones

Zones with glazed exterior walls with orientation differing by ≥ 45°

Ground floor, intermediate floors, top floor

Zones served by different types of HVAC systems

One plenum zone (if plenum returns) for each air handler


22

Example: Defining Thermal Blocks for an Office Building

152 Zones 27 Blocks 80% Reduction!


23

Weather Data

Weather is one of the primary determinants of indoor thermal conditions and space conditioning energy use. Typical Meteorological Year (TMY) data is often used to predict annual energy simulation.

A typical meteorological year (TMY) is a collation of selected weather data for a specific location, generated from a data bank much longer than a year in duration. It is specially selected so that it presents the range of weather conditions for a location, while still giving annual averages that are consistent with the long-term averages for the location.

Because TMY data represents typical rather than extreme conditions, they are not suited for designing systems to meet the worst-case conditions occurring at a location.

24

5

TEMPERATURES AND DEW POINTS

-20

-10

0

10

20

30

40

1 2 3 4 5 6 7 8 9 10 11 12

MONTH

CE

LS

IUS

5

15

25

35

45

55

65

75

FA

RE

NH

EIT

Average Dry Bulb Temperature C Average Dew Point Average Dry Bulb Temp F

Design Conditions

ASHRAE Handbook of Fundamentals

Weather Statistics & Observations

International Weather Data

DOE-2 Website (TMY, WYEC, etc)

EnergyPlus Website (EPW, CSV)

more than 2100 locations throughout the world

Wind Direction Frequency

Typical Meteorological Year

0

5

10

15

20

25

30

35

40

45

360

345

330

315

300

285

270

255

240

225

210

195

180

165

150

135

120

105

90

75

60

45

30

15

`

N

W

S

E

25

Weather Data (Cont’d)

• Fixed fee for providing energy services

Monthly Charge

• Unit cost for total quantity of energy consumed

Energy Charge

• Fee for highest or peak amount of energy used Demand Charge

• Penalty for lower than optimum power factor

Power Factor Charge

• Unit charge based on different blocks of energy use or demand

Block Charge

• Prices change during peak and off-peak times

Time of Use Rate

0–350 kWh $0.06 per kWh

350–700 kWh $0.04 per kWh

700+ kWh $0.02 per kWh

$0.40 per KVAR

$0.06 per kWh

$35 per month

$7.53 per kW

Peak Time $0.24 per kWh

Off Peak Time $0.06 per kWh

26

Utility Rate


27

Best Practices for High Quality

Building Energy Simulation

Are They Accurate?

Source: New Building Institutes “Energy Performance of LEED for New Constructed Buildings”

28

Destination

The art in energy modeling is to create a model

that is as simple as possible while still providing

reasonably accurate results. This requires good

judgment and experience.

Modeling best practices are methods incorporated into everyday practice that support:

Consistency in methods

Reduction in input errors

Generation of reasonable performance values

29

Modeling Best Practices

Source: From Michael Donn. “Quality Assurance – Simulation and the Real World” , 1999 IBPSA Proceedings . See

www.ibpsa.org/proceedings/BS1999/BS99_P-05.pdf

• Education of industry

• Robust scope of work

• Example modeling Statement of Requirements

Model preparation time limits

• Experience

• Sensitivity studies

• Published case studies

No clear guidance as to the important features of a building that should be modeled well

• Available metrics

• Systems for making comparisons Minimum QC systems to help ensure relevance of results/recommendations

• Reduce input errors

• Model represents design

• Library of similar project results

Lack of quality assurance tools in the simulation

Challenges Strategies

30

Challenges

http://doe2.com/index_Wth.html



http://apps1.eere.energy.gov/buildings/energyplus/cfm/weather_data.cfm



http://www.ibpsa.org/proceedings/BS1999/BS99_P-05.pdf



6

Key Conditions for a High Quality Energy Model

The Energy Modeler (A skilled tool user is not same as a good energy modeler)

Proficient with HVAC engineering/building physics, know how to choose

modeling software

Procedures required to achieve objectives ,good understanding with energy

codes/standards, evaluation protocols (for performance verification and

green building certification)

Knowledgeable of the inner workings of the simulation tool

Knowledgeable of the technologies being modeled

31

Key Conditions for a High Quality Energy Model

The Modeling Tool

Appropriate, robust tools matched to objectives

The Available Information

Complete information of modeled buildings – integrated approach

Actual weather data and building operation information

32

Prioritize Efforts

33

• Climate impact

• Building size, massing, process loads, ventilation

Focus on most important building details

• Characterize in detail components that change between runs

Focus on inputs that will affect the evaluation

• Aggregate HVAC zones

• Zones may be discontinuous Minimize number of

spaces/zones

• Relevant for daylighting, thermal mass, heat transfer between zones of different temperatures

Minimize interior walls

• SAT, CHW, HW resets

• Outside air flow control – occupied/unoccupied

• Part-load curves

Properly characterize HVAC and controls

Document assumptions and input values

Use pre-processing tools/spreadsheets to convert component descriptions into modeling input values

Import input file segments for complex components modeled often in projects

Make design changes incrementally in the model

34

Checking Inputs

Vetting the Output

Energy use benchmarks for typical buildings of the same use in a similar climate

Seasonal and daily energy use profiles and load profiles

Use check figures:

Total annual energy use per square meter;

Percentage of annual energy use per end-uses (heating, cooling, lighting,

equipment, fan, service hot water)

Square meter per ton of cooling

Metrics, back-of-the-envelope calculations, hourly data

Error checking and model debugging, read carefully the error/diagnostic messages

35

Input Output

Climate zone Zone and plant loads met

Weather data file Building EUI

Effective underground R-value Building plugs W/m2

Overall window U-value Building lighting W/ft2

Plug loads Building occupant density

System type, plant type Cooling - design m2/ton, kW/ton, loading

Baseline fan Cooling loop – l/s/ton

VAV - min box turn down, central heating coil Heating – W/m2, average efficiency, loading

Outside air - fixed, % supply or l/s/person, DCV;

off at night

Supply air - design l/s/m2

Controls – SAT reset, humidity, loop temp resets Ventilation air - % design flow, l/s/m2

36

Vetting the Output- Partial Checklist

7

Use Simulation Results with Caution!

Building systems are very complex! Modeling generally involves making many assumptions and simplifications.

Because of the complexity of the system, the predictions of the simulation software may not reflect the energy use of the actual building if the actual operating conditions are significantly different from those used in the model (i.e. weather, occupancy etc.).

Source: David Mather, Introduction to Computer Assisted Energy Design, 2005

37

The use of these tools should generally be restricted to comparing the performance of design alternatives given similar operating conditions, rather than predicting actual performance.

Performance verification and model calibration are important for predicting actual energy use and savings during retrofits.


38

Modeling to Inform Design

Energy Use in Buildings and Building Energy Code

Buildings account for 58% of overall energy consumption in 2008

Buildings account for 90% of electricity consumption in 2008

Most cost-effective way to reduce GHG emission.

Source: EMSD

The Bill for mandatory implementation of the Building Energy Code was passed by the Legislative Council on 24 Nov 2010.

Two subsidiary regulations under the Ordinance, namely Buildings Energy Efficiency (Fees) Regulation (Cap. 610A) and Buildings Energy Efficiency (Registered Energy Assessors) Regulation (Cap. 610B) had also been enacted in March 2011.

The Ordinance will come into full operation on 21 September 2012. The core parts (Parts 2 to 6) of the Ordinance are now within the grace period.

39

Used to Analyze Various Design Issues

Building shape and orientation

Building envelope

Thermal performance and comfort

Daylighting and artificial lighting

Natural and mechanical ventilation

Energy consumption

Microclimate, solar shading and overshadowing

Life cycle cost

1

2 3

4 5

6

8

9

1

0 7

40

Building Energy Simulation Application at Different Project Stages

• Evaluate building site selection

• Optimize building basic features such

as orientation, shape

• Evaluate HVAC system options

• Ensure building

energy code

compliance

• Evaluate energy

efficiency

measures

• Prioritize

investment in

technologies

• Finalize construction documents design

with a complete energy model

• Model change orders and examine life cycle

cost

• Ensure building operates optimally

• Verify building energy savings above

benchmark building using post-occupancy

building performance data

41

Example 1: Optimization of External Shading

97.5%

98.0%

98.5%

99.0%

99.5%

100.0%

100.

99.8 99.7

99.6 99.7

99.5

99.7 99.8

99.9

Base

Design

0+1’ fin at

5’ interval on NE, NW

0+1’ fin at 5’

int+21” ext light shelf

on NE, NW

0+1’ fin on

NE, NW+20” ext light

shelf on SE,

SW

0+1’ fin on NE,

NW+30” ext light shelf on

SE, SW

0+1’ fin+int LS

on NE, NW+ 30” ext light

shelf on SE,SW

0+2’ fin at 5’

interval

0+2’fin at 10’

interval

0+2’fin at 20’

interval

0+2’fin at 20’

interval

99.7

42

8

Example 2: Optimization of HVAC Systems

Envelope

and

Lighting

Cumulativ

e

Premium

Motors and

Improved

Fan

Efficiency

Improve

d Chiller

Efficienc

y

Energy

Recovery

VFD on

Cooling

Tower

Evap

Cooling

Underfloor

Air

75.0%

85.0%

90.0%

95.0%

100.0%

80.0%

100 99.6 99.5

97.0

99.9 99.6

89.9

43

Show a path to a desired goal – communicate to the owner/architect early

on that this is important! 44

Example 3: Supporting the Business Case

The most efficient, cost effective building designs can be achieved by integrating whole building energy analysis into the design process as early as possible—preferably at the concept/schematic design phase.

45

Integrated Design Process – Cost Comparison

Typical Integrated

Design

Development

Construction

Documents

Schematic

Design

Construction

Admin Project Closeout

Pre-design

Design

Development

Construction

Documents

Schematic

Design

Construction

Admin

Pre-design

Project Closeout

46

Integrated Design Process – Time Comparison

Align team around energy-related goals

Make design recommendations EARLY to increase potential for impact

Identify where efforts should be focused to maximize energy savings and equipment downsizing

Maximize opportunity for energy efficiency

Goal Setting Technical Potential

“Right Steps” Energy

Modeling

Modeling Objectives

47

Integrated Design Process

(1) Define Needs

(2) Identify Appropriate Measures

(3) Reduce Loads

(4) Select Appropriate & Efficient Technology

(5) Plan System Layouts

(6) Optimize Operation

(7) Seek Synergies

(8) Explore Alternative Power

Most people start

here!

48

Integrated Design Process – The Right Steps in The Right Order

9

Integrative Design Process – Iterative Analysis Procedure

Optimize Load Reduction Strategies

Resize and Reselect

Mechanical Equipment

Compare Metrics to Benchmarks

and Goals

Use LCCA to Evaluate Options

49 Current

Energy Use

An

nu

al

En

erg

y U

se

1

2

What is the maximum level of energy savings for this building

given today’s technology?

Co

olin

g E

nerg

y U

se

Raise Cooling

Setpoint Envelope & OA

Savings Reduce Internal

Gains Cooling Efficiency

Cooling T-Min Existing Cooling

65% Savings 300 kWh/m2/yr

50

Example: Technical Potential Exercise

Source: Building Energy Modeling Training Workshop at AEE’s 2010 conference

Current

Energy Use

An

nu

al

En

erg

y U

se

1

2

Technical

Potential

3

4

Implementable

Minimum

5

What is the maximum level of energy savings for this building

given today’s technology?

300

kWh/m2/yr

51



Technical Potential:

100 kWh/m2/yr

Baseline: 300 kWh/m2/yr

67

% S

avin

gs

Implementable Minimum:

185 kWh/m2/yr

52



Energy and CO2 savings result from 8 key projects.

9% 6%

5% 5%

5% 3% 3% 2%

0

100,000

200,000

300,000

Ann

ual E

nerg

y U

se (

kWh)

Annual Energy Savings by Measure

38%

Reduction

53

Example: Implementable Minimum



54

A Guide to Energy Simulation Software

10

Building Energy Software Tools

Whole Building Analysis

• Energy Simulation

• Load Calculation

• Renewable Energy

• Retrofit Analysis

• Sustainability/Green Buildings

Codes & Standards

Materials, Components, Equipment, & Systems

• Envelope Systems

• HVAC Equipment and Systems

• Lighting Systems

Other Applications

• Atmospheric Pollution

• Energy Economics

• Indoor Air Quality

• Multi-building Facilities

• Solar/Climate Analysis

• Training

• Utility Evaluation

• Validation Tools

• Ventilation/Airflow

• Water Conservation

• Misc. Applications

Source: http://apps1.eere.energy.gov/buildings/tools_directory/subjects_sub.cfm

55

Simulation Software = GUI + Simulation Engine

Most building energy simulation programs come with a graphical user interface (GUI) as well as the actual simulation engine. The former is used to prepare simulation input files for the latter and to display simulation results once a simulation is complete.

The developers of simulation engines and GUIs often work for different companies with the engine being developed at public organizations (government lab & universities) whereas GUIs are more often developed by commercial vendors. As a result there can be several GUIs for the same simulation engine.

While the choice of GUI determines the ease of use if a simulation program, it is ultimately the engine that determines how reliable simulation results are. A great GUI with a weak engine cannot yield reliable results!

VisualDOE

(DOE2.1)

eQUEST

(DOE2.2)

Green Building

Studio

(DOE2.2)

DesignBuilder

(EnergyPlus)

IES

(Apache)

Source: Diego Ibarra and Christoph Reinhart, DesignBuilder / EnergyPlus ‘Tutorial #1’ Getting Started, 2009

56

Building Energy Simulation Software Tools

There are hundreds of building energy simulation programs available. The US. Department of Energy website provides a directory containing information on 395 building software tools.

http://apps1.eere.energy.gov/buildings/tools_directory/

57

Source: Hui, S, 2011. MEBS6016 Energy Performance of Buildings

Building Energy Simulation Software Tools(Cont’d)

58

History

DOE-2

BLAST

ESP-r

Trace

HAP

TAS

eQuest

EnergyPlus

IES-VE

1970 1980 1990 2000

59

Most Widely Used Hourly Simulation Software Tools

Energy10

– Good for small, 1-2 zone buildings

– Conceptual design tool

– SBIC Non-Member Price: $375, for Student/ Faculty discount

HAP

– Bestested to DOE-2

– Compares energy consumption and operating costs of design alternatives

– Limited ability to calculate interactions between some strategies

– Typically used for HVAC system sizing

– HK$12,000 (Basic) plus $5,000 (approx) for each software upgrade (single and

up to 10 concurrent users per site)

TRACE

– Simplified input methods

– Models more than 25 types of air distribution systems

– Typically used for HVAC system sizing, requires TRACE 700 to perform energy

and cost analyses

60

http://apps1.eere.energy.gov/buildings/tools_directory/

11

Most Widely Used Hourly Simulation Software Tools (Cont’d)

DOE-2 based

– VisualDOE, an interface to DOE2.1E; cost is $980 + tax for a single commercial

license

– eQuest, an interface to DOE2.2 (further developed based on DOE-2.1E), free

– eQuest is most widely used for LEED assessment

TRNSYS

– Modular system that makes it very flexible

– Consists of a graphical interface, simulation engine and a library of components

– Building input s are object-oriented, non-geometrical.

– Difficult interface, very detailed modeling options

– Educational: $2250, Commercial: $4740

EnergyPlus

– More advanced modeling capabilities

– Modular programming structure

– Interfaces currently in development, some third-parties interfaces are available

– Difficult and time consuming to use in practice to model a complex building

– Free for EnergyPlus, various costs for interfaces

61


ESP-r

– Open source program

– Transient energy simulation based on finite volume technique

– Has a strong research heritage

– Free

Tas

– Simulates the thermal performance of buidings

– A suite of software products consists of Tas Building Designer, Tas Systems, Tas

Ambiens

– £5250 for a single perpetual license (including mandatory one year maintenance

and support) ; Second and subsequent perpetual licenses are sold at 50% of the

original cost

62


IES <VE>

– A range of design-oriented building analysis within a single software environment

– Capabilities include thermal analysis, daylighting, HVAC, CFD, solar geometry, an

integrated modeling environment

– Uses ApacheSim for thermal simulation, ApacheHVAC for HVAC system

simulation

– Recently enhanced chiller modeling in ApacheHVAC

– Quite expensive

Ecotect

– More user friendly and better for complex geometries, nice visualization

– Great for passive design analysis

– Good for schematic, conceptual design (no real HVAC analysis)

– Export to powerful simulation tools (EnergyPlus)

63

Contrasting the Capabilities of Building Energy Performance Simulation

A report provides detailed comparison of 20 major building energy simulation programs (Crawley, D. B., Hand, J. W., Kummert, M. and Griffith, B. T., 2005).

64

General Modeling Features

Table 1 General Modeling Features

Ene

rgyP

lus

eQ

UES

T

IES

<VE>

Tas

Simulation solution

Simultaneous loads, system and plant solution X X X X

Iterative non-linear systems solution X X X

Coupled loads, systems, plant calculations X X X

Space temperature based on loads-systems feedback

X X X

Floating room temperatures X X X X

Time step approach

User-selected for zone/environment interaction X X

Variable time intervals for zone air/HVAC system interaction X X

User-selected for both building and systems X

Dynamically varying based on solution transients X

Full Geometric Description

Walls, roofs, floors X X X X

Windows, skylights, doors, and external shading X X X X

Multi-sided polygons X X X X

Import building geometry from CAD programs X X X X

Export building geometry to CAD programs X X X

Import/export model to other simulation programs X

Number of surfaces, zones, systems, and equipment unlimited X X X X

Simple building models for HVAC system simulation

Import calculated or measured loads X X

Source: Crawley, D. B., Hand, J. W., Kummert, M. and Griffith, B. T., Contrasting the Capabilities of Building Energy Performance Simulation, 2005.

65


Zone Loads

Table 2 Zone Loads

Ene

rgyP

lus

eQU

EST

IES

<VE>

Tas

Heat balance calculation X X X X

Building material moisture adsorption/desorption X X X

Element conduction solution method Frequency domain (admittance method) X Time response factor (transfer functions) X X X Finite difference / volume method X

Interior surface convection Dependent on temperature X X X Dependent on air flow X X Dependent on CFD-based surface heat coefficient X User-defined coefficients X X X

Internal thermal mass X X X X

Human thermal comfort Fanger X X X Kansas State University X X Pierce two-node X MRT (Mean Radiant Temperature) X X X Radiant discomfort X X

Automatic design day sizing calculations Dry bulb temperature X X X X Dew point temperature or relative humidity X X X X User-specified X X X X

66

12

Building Envelope, Daylighting and Solar


Table 3 Building Envelope, Daylighting and Solar

Ene

rgyP

lus

eQU

EST

IES

<VE>

Tas

Solar analysis

Beam solar radiation reflection from outside and inside window reveals X

Solar gain through blinds accounts for different transmittances for sky and ground diffuse solar

X X X

Solar gain and daylighting calculations account for inter-reflections from external building components and other buildings

X X X

Shading surface transmittance X X X X

Shading device scheduling X X X X

User-specified shading control X X X

Bi-directional shading devices X X X

Shading of sky IR by obstructions X X X X

Advanced fenestration

Controllable window blinds X X X X

Between-glass shades and blinds X X X X

Electrochromic glazing X X

Datasets of window types X X X X

WINDOW 5 calculations X X

WINDOW 4.1 data import X

Dirt correction factor for glass solar and visible transmittance X

Movable storm windows X X X

Bi-directional shading devices X X X

Window blind model X X X

User-specified daylighting control X X X

Window gas fill as single gas or gas mixture X X X

67

Table 4 Infiltration, Ventilation, Room Air and Multizone Airflow

Ene

rgyP

lus

eQ

UES

T

IES

<VE>

Tas

Single zone infiltration X X X X

Automatic calculation of wind pressure coefficients X X

Natural ventilation X X X

Hybrid natural and mechanical ventilation X X

Window opening for natural ventilation controllable X X X

Multizone airflow (via pressure network model) X X X

Displacement ventilation X X X

Infiltration, Ventilation, Room Air and Multizone Airflow


68

Table 5 Renewable Energy Systems

Ene

rgyP

lus

eQ

UES

T

IES

<VE>

Tas

Trombe wall X X X X

Solar thermal collectors

Glazed flat plate X X X

Unglazed transpired solar collector X

Photovoltaic power X X X

Renewable Energy Systems


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Table 6 Electrical Systems and Equipment

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T

IES

<VE>

Tas

Electric load distribution and management

On-site generation and utility electricity management including demand X X

Power generators

Internal combustion engine generator X X

Combustion turbine X X

Grid connection X

Electric conductors X

Building power loads X X X X

Electrical Systems and Equipment


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Table 7 HVAC Systems

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lus

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EST

IES

<VE>

Tas

Discrete HVAC components X X X

Idealized HVAC systems X X

User-configurable HVAC systems X X X X

Air loops X X X

Fluid loops X X X X

Run-around, primary and secondary fluid loops with independent pumps and controls X X

Fluid loop pumping power X

Air distribution system X X X

Multiple supply air plenums X X

Simplified demand-controlled ventilation

Ventilation rate per occupant and floor area X X X X

Ventilation air flow schedule X X X X

User-defined ventilation control strategy X X

CO2 modeling

CO2 zone concentrations, mechanical and natural air path transport X

CO2 based demand-controlled ventilation X

Automatic sizing

HVAC components X X X X

Air loop flow, outside air, zone airflow X X X

Hot, cold, and condenser water loops X X X X

HVAC Systems


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Table 9 Environmental Emissions

Ene

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lus

eQ

UES

T

IES

<VE>

Tas

Power plant energy emissions X X X X

On-site energy emissions X X X X

Major greenhouse gases (CO2, CO, CH4, NOx) X X X X

Carbon equivalent of greenhouse gases X X X

Criteria pollutants (CO, NOx, SO2, PM, Pb) X X

Ozone precursors (CH4, NMVOC, NH3) X

Hazardous pollutants (Pb, Hg) X

Water use in power generation X

High- and low-level nuclear waste X

Pollutant emissions factors X

Environmental Emissions


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13

Table 10 Climate Data Availability

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lus

eQU

EST

IES

<VE>

Tas

Weather data provided

With the program X X X X

Separately downloadable X X X X

Generate hourly data from monthly averages X

Estimate diffuse radiation from global radiation X X X

Weather data processing and editing X X X

Weather data formats directly read by program

Any user-specified format X X

EnergyPlus/ESP-r X X

Typical Meteorological Year X X

Typical Meteorological Year 2 X X X

Solar and Wind Energy Resource Assessment X

Weather Year for Energy Calculations 2 X X

Solar and Meteorological Surface Observation Network X

International Weather for Energy Calculations X

DOE-2 text format X X

BLAST text format X

ESP-r text format X

ECOTECT WEA format X

Climate Data Availability


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Table 11 Economic Evaluation

Ene

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lus

eQ

UES

T

IES

<VE>

Tas

Energy Costs

Simple energy and demand charges X X X X

Complex energy tariffs X X X

Scheduled variation in all rate components X X X X

User selectable billing dates X X

Life-cycle costs

Component and equipment cost estimating X X X

Standard life-cycle costing X X

Economic Evaluation


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Table 12 Results Reporting

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Tas

Meters

Energy end-uses X X X X

Peak demand X X X X

Peak demand period user-selectable X X X X

Consumption by energy source X X X X

Components user-assignable to any meter X X X Multiple levels of sub-metering X

Auto-sizing report X X X X Automatic generation of energy balance checks X X X Visual surface output (walls, windows, floors, roofs) X X X X HVAC system/flow network diagramming X X X Graphical definition of simulated system X X

Results Reporting


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eQUEST — the Quick Energy Simulation Tool

eQUEST was designed to allow users to perform detailed analysis of today’s state-of-the-art building design technologies using today’s most sophisticated building energy use simulation techniques but without requiring extensive experience in the "art" of building performance modeling.

The principal focus of eQUEST is to make detailed hour-by-hour simulation more reliable and affordable for a broader base of design and buildings professionals

eQUEST is developed by James J. Hirsch & Associates (JJH), supported as a part of the Energy Design Resources program which is funded by California utility customers.

Source: http://www.doe2.com

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eQUEST=DOE-2+Wizards+Graphics

an enhanced

DOE-2-derived building energy

use simulation program

building model

creation wizards, energy

efficiency measure wizard

a graphical

results display module

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eQUEST was developed around the simulation program of DOE-2.2.

DOE-2.2 was further developed and upgraded from DOE-2.1E. DOE-2.1E was developed by James J. Hirsch & Associates (JJH) in collaboration with Lawrence Berkeley National Laboratory (LBNL).

DOE-2.2 extends and expands DOE-2.1E's capabilities in interactive operation, dynamic/intelligent defaults, and improvements to numerous long-standing shortcomings in DOE-2.1E. Most of the extensive changes are in the HVAC area - particularly in the central plant descriptions.

eQUEST’s engine is “DOE-2.2”

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14


Building Creation Wizards

Schematic Design Wizard (SD Wizard)

Describe the building’s architectural features and its HVAC.

Designed to support the earliest design phase when information is most

limited.

Design Development Wizard (DD Wizard)

Designed for later, more detailed design, when more detailed information

is available.

Energy Efficiency Measure Wizard (EEM Wizard)

Describe up to 9 design alternatives to building description; help to easily

weigh the energy impacts and tradeoffs of the design options.

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Visualize the results through a number of graphical formats after simulation

• Overall building estimated energy use can been displayed on an annual or monthly basis.

• Detailed performance of individual building components may be examined.

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Simulation Methods

Heat transmission through opaque exterior surfaces

• “delayed” method via conduction transfer functions;

• “quick” method via steady-state UAΔT calculations.

Heat transmission through transparent surfaces

• Shading coefficient method;

• A predefined glass library;

• Layer-by-layer method.

Interior sunlight/daylight modeling

• Detailed tracking of the “direct” daylight component;

• Uses the “split-flux” method for “indirect” component: predicts average reflected daylight levels and neglects internal obstruction of complex fenestration/spatial configurations

Source: www.doe2.com/download/equest/eQUESTv3-Overview.pdf

81

Space Loads

• DOE-2’s standard and /or custom weighting factors methods

Coil Loads

• Coupled in DOE-2.2 with water-side calculations into the same time step.

Water-Side

• Based on temperature and flow and very modular (i.e. allows for flexible coupling or assignment of primary and secondary equipment).

Simulation Methods (Cont’d)

Source: www.doe2.com/download/equest/eQUESTv3-Overview.pdf

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Systems Available in Building Creation Wizards

Cooling Source Heating Source System Type

No cooling No heating Unit Ventilator

No cooling Furnace/Elec Resist/HW Coils

Gas/Fuel/Electric/Hot Water Furnace with/without zone ventilation

No cooling Baseboards Electric Baseboards with/without zone ventilation

DX coils No heating/ Furnace/ Elec Resist/ DX coils

Packaged Single Zone DX / Split system Single Zone DX / Packaged Terminal AC / Packaged VAV

DX coils HW coils Packaged VAV with Hot Water Reheat

CHW coils No heating/ HW coils

Standard VAV/ Parallel Fan-Powered VAV/ Series Fan-Powered VAV/ Air Handler/ FCU

Evap cool No heating/ Furnace/ Elec Resist

Indirect/Direct Evaporative Cooler

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Dual-fuel cooling plants

Primary/Secondary chilled water distribution systems

Variable flow primary distribution systems

Dual-fan dual duct and multi-zone VAV systems

Natural ventilation

Water-loop and ground-source heat pumps

Thermal energy storage

Cogeneration

Ice sinks and industrial refrigeration systems

Custom performance curves

Underfloor air distribution (requires significant user judgment and some advanced design features)

Photovoltaic

Systems Available in Detailed Mode

84

15

Utility Rates

Inclined or declining block rates

Hours use rates

Time-of-use rates

Ratchets

Rate limiters

Customer service/meter charges

Taxes/surcharges

Fuel adjustments

85

Installing eQUEST

Visit www.DOE2.com/eQUEST

Download the latest version of eQUEST.

eQUEST is FREE.

86


87

Energy Simulation for BEAM Plus

and LEED Certification

BEAM Plus EU Credit 1 Reduction of CO2 Emissions

The number of credits (1 to 15) to be awarded will be determined wrt % reduction of CO2 emissions or annual energy consumption of the assessed building relative to the respective benchmark (zero-credit) criteria evaluated from the Baseline Building model.

Methodology of energy simulation shall make reference to Performance-based Building Energy Code (PBEC) or Appendix G of ASHRAE 90.1-2007 or equivalent.

88

LEED EA Credit 1 Optimized Energy Performance

Demonstrate a percentage improvement in the proposed building performance rating compared with the baseline building performance rating. Calculate the baseline building performance according to Appendix G of ANSI/ASHRAE/IESNA Standard 90.1-2007 (with errata but without addenda1) using a computer simulation model for the whole building project.

89

48%

46%

44%

42%

40%

38%

36%

34%

32%

30%

28%

26%

24%

22%

20%

18%

16%

14%

12%

Energy cost saving

1 point 19 points

Performance-based Building Energy Code (PBEC)

Source: Guidelines on Performance-based Building Energy Code 2007

90

http://www.doe2.com/eQUEST

16

91

Performance Rating Method Appendix G of ASHRAE 90.1

Purpose

• Intended to show relative performance compared against a minimally compliant ASHRAE 90.1 building that represents standard practice

Not Code Compliance

• Not intended to show minimum code

compliance

Function

• Credits or penalizes many measures

that are held constant for minimum

code compliance

92

Performance Rating Method Appendix G of ASHRAE 90.1(Cont’d)

The use of an hour-by-hour, full-year, multiple-zone numerical analysis for modelling and simulating the building energy performance is required

A design model is built in accordance with actual design and guidelines in Appendix G of ASHRAE 90.1 or PEBC

If energy cost saving of the design building does not meet the targeted value, energy efficiency measures can be introduced in the design model to assess their feasibility and cost-effectiveness.

Build a Design Model

93

Build a Design Model (Cont’d)

Weather data

Envelope as actual design

MEP as actual

design

Utility Same as baseline design

Occupancy and plug loads same as baseline design Lighting as actual design

High efficiency HVAC system, Heat recovery …

Better glazing, Shading devices, …

Daylighting, Energy-efficient appliances …

94

BEAM Plus EU Credit 1 Reduction of CO2 Emissions Example Inputs


95


96

BEAM Plus EU Credit 1 Reduction of CO2 Emissions Example Inputs (Cont’d)

17


97



98


Energy Model Example

99

Energy Model Example (Cont’d)

Monthly Electricity Consumption of Assessed Building Model

Monthly Electricity Consumption of Baseline Building Model

100


101

Available Resources

Available Resources

BLDG-SIM — A free e-mail list for all building energy simulation program users to ask questions to other users.

EnergyPlus Support Group on Yahoo - A user-to-user email list where you can ask questions of other users.

TRNSYS-users -- TRNSYS users mailing list at the Solar Energy Lab, UW-Madison

Building Energy Simulation User News — Bi-monthly newsletter for users of DOE-2, BLAST, EnergyPlus, Genopt, SPARK, Energy-10, and Building Design Advisor

102

18

Available Resources (Cont’d)

http://www.arch.hku.hk/research/beer/best.htm – a website of HKU Architecture that introduces concept, principles and tools of building energy simulation

International Building Performance Simulation Association — A not-for-profit international society dedicated to improving the built environment.

ASHRAE Technical Committee 4.7 Energy Calculations — TC 4.7's Goal: Accurate energy models at every engineer's fingertips

103

The BEAM Plus Standards (NB and EB)

BEAM circular letters and FAQ for BEAM Plus

Frequently Asked Questions

Circular Letter

For information of BEAM Plus

project certification, BEAM

Professional, and BEAM Faculty,

visit

http://www.hkgbc.org.hk/eng/Gr

eenBuildingLabelling.aspx


Provides guidance on how to prepare the review documentation for EA Credit for LEED NC v2.2, LEED CS v2.0 and LEED for Schools rating systems.

Provides technical guidance for the performance compliance path (whole energy simulation) based on based on the primary energy standards and codes: ASHRAE Standard 90.1-2004, California Title 24-2005, and Oregon Energy Code 2005.

Purchase from the USGBC website http://www.usgbc.org/Store/PublicationsList_new.aspx?CMSPageID=1518

Source: Advanced Energy Modeling for LEED Technical Manual v1.0

105

Advanced Energy Modeling for LEED Technical Manual v1.0


1/F Jockey Club Environmental Building,

77 Tat Chee Road, Kowloon, Hong Kong

香港九龍塘達之路77號賽馬會環保樓1樓

T +852 3610 5700

F +852 3996 9108

www.beamsociety.org.hk

1/F Jockey Club Environmental Building,

77 Tat Chee Road, Kowloon, Hong Kong

香港九龍塘達之路77號賽馬會環保樓1樓

T +852 3610 5700

F +852 3996 9108

www.beamsociety.org.hk

106

http://www.ibpsa.org/

http://www.ibpsa.org/

http://tc47.ashraetcs.org/

http://www.hkgbc.org.hk/eng/GreenBuildingLabelling.aspx

http://www.hkgbc.org.hk/eng/GreenBuildingLabelling.aspx