EcoDesigner

Graphisoft’s New Building Information Modeling Tool Brings Energy Efficiency to Forefront of Architectural

Design

By: Miklos Sved

Architect

GRAPHISOFT EcoDesigner Product Manager

Budapest, June 28th, 2009

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Contents:

Text: 1. Let ”Green” Become an Organic Part of the Architectural Design Workflow ..................... 3 2. Putting the Virtual Building at the Heart of Energy Analysis .............................................. 4 3. Real-Time Evaluation of Design Alternatives in the Conceptual Design Phase ................ 5 4. BIM Geometry Analysis ...................................................................................................... 6 5. Discussion Between Architect and Project Energetics - the EcoDesigner Dialog ............. 7 5.1. Project Location and Function............................................................................................ 7 5.2. Relevant Building Structures .............................................................................................. 9 5.3. Openings on the Building Shell ........................................................................................ 10 5.4. MEP Systems And Energy Settings ................................................................................. 11 6. The Calculation Engine .................................................................................................... 12 7. Energy Balance Evaluation Report .................................................................................. 12 8. The EcoDesigner Advantage............................................................................................ 14

Illustrations: Picture 1.: Decision-making during the architectural design process ......................................... 3 Picture 2.: Intelligent “BIM” model of office building.................................................................... 4 Picture 3.: Design variations of single family house.................................................................... 5 Picture 4.: Color-coded marking of relevant building structures ................................................. 6 Picture 5.: Internal temperature and heat gain profiles of different building functions................ 8 Picture 6.: The Structures tab page of the EcoDesigner main dialog......................................... 9 Picture 7.: EcoDesigner’s built in Openings Catalog ................................................................ 11 Picture 8.: Project Key Values and Energy Consumption evaluation ....................................... 13 Picture 9.: Carbon Footprint information and the Monthly Energy Balance bar chart .............. 14

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1. Let ”Green” Become an Organic Part of the Architectural Design Workflow

Approximately 80% of the design decisions that influence a building's energy performance are

made by the architect in the early design phase; the remaining 20% are made by engineers at the

later phases of design.

Earlier energy modeler software programs were targeted exclusively at energy experts who

typically joined the design process at the end of the development phase. By that point, most

important design decisions – including zoning, orientation, floor plan layout, lighting, MEP system

types - were already made. Thus, the results of the energy experts’ evaluation had limited effect

on the project. Apart from some minor adjustments, the original design concept remained intact

whether it was ecologically suitable or not.

80% OF MAJOR DECISIONS

EXISTING GREEN SOLUTIONS

2.DESIGN

DEVELOPMENT

1.SCHEMATIC

DESIGN

3.CONSTRUCTION

DOCUMENTATION

ECODESIGNER

Picture 1.: Decision-making during the architectural design process

Today, increasing ecological awareness in every sphere of human activity, including the

construction industry, has spurred the development of a more effective design tool: one that can

be applied on projects of any size at the schematic design phase, enabling design concepts that

are ecologically sound from their very foundations, not just as an additional feature.

Investors worldwide appreciate the value and financial sense of developing a truly green design,

and architects who actively make 'green' decisions early on are saving their clients real money, in

both the short and long term. Research on contemporary architectural design practices confirms

that architects need a quick, reliable energy performance evaluation tool at the earliest stages of

the design process.

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2. Putting the Virtual Building at the Heart of Energy Analysis

Traditionally, building energy modeling software programs could be used effectively only by

experts in building services. This expert-level energy evaluation was carried out as an isolated

process that was not integrated into the rest of the design activity. Such software solutions

demanded input of detailed data that was typically unavailable at the schematic design phase.

Another major disadvantage of these programs was that gathering and inputting the massive

amounts of volume and surface data was an extremely tedious and time-consuming activity. If

done without the aid of automation, the process was bound to be rife with errors, and the

accuracy of the resulting database did not meet the standards set by the rest of the application.

The Graphisoft Custom Solutions team embarked upon developing a whole new approach to

energy evaluation. Our top priorities were to break free from these ineffective conventions, to

minimize and simplify user input, and to provide a continuous, highly automated workflow.

The result of our work is Graphisoft EcoDesigner, an application that allows architects to perform

reliable energy evaluation of their Virtual Building within ArchiCAD. Due to the automatic structure

geometry analysis algorithm, the evaluation process requires relatively few, simple and

straightforward user inputs. A certified calculation engine performs dynamic building energy

evaluation, providing information on the project’s yearly energy consumption, carbon footprint and

monthly energy balance.

Picture 2.: Intelligent “BIM” model of office building

With EcoDesigner, the ArchiCAD Virtual Building becomes an even more intelligent "BIM" model.

The program provides easy access to much-needed energy information concerning architectural

projects in the early design phase, when changes are easy to effectuate, as opposed to detailed

analysis at a stage when the design is well advanced and decisions have already been made.

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This product is not a high-end energy calculation software; it does not produce accredited energy

analysis output suitable for official documentation according to local codes and code ratings. The

Export function button, available within EcoDesigner, activates the Export to VIP Energy dialog

box, which enables the user to save all calculation input data in VIP Energy input file format. The

saved file can then be opened using the StruSoft VIP-Energy software for detailed energy

analysis of the designed building.

EcoDesigner is available for two platforms:

• Windows version for computers running Windows XP or Vista, and

• MacOS version for MacIntel computers running Mac OSX 10.4 or higher.

3. Real-Time Evaluation of Design Alternatives in the Conceptual Design Phase

"Sustainable architecture" is the practice of designing, constructing and maintaining buildings in a

way that minimizes their environmental impact. A key aspect of sustainable design is energy

efficiency: the attempt to reduce the amount of energy a building consumes over its life-span.

Relationships between building volumes, proposed area and orientation of glazed surfaces, as

well as the properties of shading, all greatly influence energy consumption. Selecting the right

alternative, which delivers better energy performance, is vital for developing a successful project

that lives up to current and future standards.

Picture 3.: Design variations of single family house

EcoDesigner is optimized to help architects evaluate energy efficiency and compare early design

variations based on yearly energy consumption, carbon footprint and monthly energy balance.

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To bring the energy evaluation module closer to the CAD modeler software, EcoDesigner has

been developed as a direct add-on application to the popular Graphisoft ArchiCAD 12. The

simple yet effective three-step workflow of the program (Analyze > Calculate > Results) makes

energy evaluation a task that is as easy as generating a section or a 3D view from the Virtual

Building model.

4. BIM Geometry Analysis

The basis of the energy evaluation is the Virtual Building model created by the architect in

ArchiCAD for the usual purposes: client presentations or design documentation. However, while

the aforementioned conventional methods of energy evaluation usually require some sort of data

export or mapping, EcoDesigner works directly within the CAD software – this minimizes data

loss or distortion along the way, and maximizes calculation accuracy. Energy balance evaluation

can be carried out on the full model, or only a selected part of it – just select the desired area

using the marquee tool.

Picture 4.: Color-coded marking of relevant building structures

When launched, EcoDesigner activates the automatic structure mark-up function that selects and

groups structures based on their relevance in energy calculations. For easier identification, the

marked-up structures are differentiated by color on the floor plans and in the 3D view according to

their types: internal structures, roofs, external walls, floors on ground, basement walls and

basement floors.

Since such analysis and grouping of building structures is often a complex and intricate task,

human judgment may override the computer-generated selection sets: the analysis can be

adjusted manually. EcoDesigner’s user-friendly floating palette enables the user to fine-tune the

structure markup made by the program.

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After the selection sets are approved by the user, the necessary geometric data of the marked up

structures (orientation, CAD element type and fill, surface area, volume and thickness) and the

building itself (building volume and tempered floor area) are acquired by the computer and

displayed on the Building shell elements list of the Structures tab page of EcoDesigner.

5. Discussion Between Architect and Project Energetics - the EcoDesigner Dialog

The EcoDesigner four-tab-page dialog box serves two purposes: it allows users to provide input

needed to complete the energy evaluation; and it displays the lists of data obtained by the model

analysis described above, enabling the user to attach further relevant parameters to the list

entries.

5.1. Project Location and Function

On the first tab page, entitled Location and Function, project location is given by geographical

coordinates and a custom name. Using the geographical coordinates and the time zone provided,

the program obtains relevant weather data (air temperature, relative humidity, wind speed and

solar radiance hourly values for one reference year) from an online weather database, or, in case

of cities present in ArchiCAD by default, from the database within EcoDesigner. Once the

weather data has been downloaded, it is stored within the application, so internet connection is

only needed the first time a certain project is evaluated.

The editable project orientation provides direct access to the Project North settings of the BIM

model from within the energy evaluation application. Based on the Project North defined here,

EcoDesigner recognizes eight different orientations (North-West, West, South-West etc.) and

uses these to evaluate the building structure.

The numeric input entered at the Grade level to project zero setting, together with the

Underground insulation settings provided at the Structures tab page, enable the program to

correctly evaluate linear thermal currents. Building structures that are in direct contact with the

ground are evaluated using a different algorithm, since linear heat loss is far more significant than

surface-related heat loss in these structures.

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While other energetic modeler programs require numeric input, EcoDesigner prefers linking

numeric data to easily understandable terms, to enhance usability. Settings such as wind

protection and the rate of solar reflection from surrounding surfaces illustrate this approach: the

user just selects a predefined option from the dropdown menus.

There are two different ways to define shading properties of the Virtual Building within

EcoDesigner.

• Vertical and horizontal edges of external objects, or projecting parts of the building

envelope itself, cast shadows on the elevations. For each building orientation, the user

chooses applicable Shading and Complexity settings, under the Façade shading option

of the Location and Function tab page.

• The user may assign various shading devices to openings on the building shell. This is

done on the Openings tab page.

Picture 5.: Internal temperature and heat gain profiles of different building functions

In order to carry out a successful energy evaluation, building function must be defined. Required

hourly internal temperature data and internal heat gains (from humans, lighting, equipment and

hot water generation) are linked to each predefined building activity type (offices, residential

buildings, schools, hospitals, food services, retail, various industries, performance spaces and

parking/service areas) within EcoDesigner. The program enables the evaluation of multi-

functional buildings as well: it is possible to combine up to three different building functions within

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a single project quickly. The matching package of extensive background information is attached

to each activity, and graphs illustrate the performance data in a user-friendly manner.

5.2. Relevant Building Structures

The Structures tab page displays geometric data - obtained by the BIM Geometry Analysis - for

the whole building (tempered volume and floor area), as well as data for selected structures.

Besides orientation, CAD element type, fill type, surface area and skin thickness, the Building

shell elements list contains additional relevant physical properties (heat transmission coefficient,

surface type and infiltration rate). These properties must be assigned by the architect using the U-

value calculator, which can be accessed from the Building shell elements list.

Picture 6.: The Structures tab page of the EcoDesigner main dialog

The U-value calculator enables the user to ‘build up’ composite structures by selecting items from

the material catalog included in the program. This catalog lists numerous building materials with

their thermal conductivity, density and heat capacity values. Static heat transmission coefficients

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of external building envelope structures, after being further modified according to the thermal

bridge effect of construction details, are automatically displayed on the U-value calculator panel.

The calculation engine eventually uses the geometry data and the assigned physical properties of

the composite skin orders for dynamic temperature drop calculation and determines the resultant

U-values for every hour of the year.

Depending on local convention, some users may prefer to use the R value (Thermal Resistance

Coefficient), which is the inverse of the U value, therefore listing and displaying R values instead

of U values is possible both on the dialog and in the final Evaluation Report.

The Structures tab page also contains the Internal heat storage mass (heavy, medium or

lightweight) and Underground insulation settings needed to evaluate linear thermal currents in

building structures that are in direct contact with the ground.

The Model review function button enables the architect to leave EcoDesigner temporarily, without

closing it, to change the building model or to alter the previously defined structure markups, and

thus to modify the structure selection sets.

5.3. Openings on the Building Shell

This tab page lists geometric data of openings (orientation, CAD opening type and surface area)

obtained by the BIM Geometry Analysis. Additional relevant physical properties (glazing

percentage, U-value, solar transmittance and infiltration rate) are assigned by the user by

selecting products from the built-in Opening catalog. Manual data entry is also possible, if specific

product properties are already available at the time of the evaluation.

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Picture 7.: EcoDesigner’s built in Openings Catalog

Shading devices may also be attached to each entry of the list separately, by selecting one of the

predefined types: curtains, venetian blinds, roller blinds, awnings, external blinds, external

adjustable louvers, or shutters. EcoDesigner’s dynamic evaluation takes into account the fact that

some shading devices are only activated when needed, that is, when the temperature and/or

solar radiation inside become too high. Furthermore, external shading devices become ineffective

if the windspeed exceeds the threshold value specified for the applied product.

5.4. MEP Systems And Energy Settings

The energy balance evaluation requires some basic user input concerning the MEP systems to

be installed in the planned building. On this tab page, the user must define the proposed cooling

and ventilation type, and may also define additional devices such as air-to-air energy recovery

systems, heat pumps and solar panels.

If the user enters additional local data such as currency and used energy type into the Energy

sources and costs dialog box, then EcoDesigner also estimates the project’s carbon footprint and

energy costs.

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6. The Calculation Engine

Once all necessary input data is obtained, EcoDesigner provides it to the VIPCore Calculation

Engine as an XML file. The engine then performs the dynamic energy evaluation and sends the

results back to EcoDesigner in XML format.

The calculation engine relies entirely on dynamic models, in which every model is broken down to

a level at which facts and behavior are known. The calculation is repeated every hour. The

accuracy of each model has been validated and verified against real buildings.

When calculating a building’s energy consumption, the program utilizes known or measured facts

about all parts of the energy flow. The energy flow is calculated taking climate factors

(temperature, sun, humidity and wind) into consideration. Other factors in the calculation include

the varying room temperature requirements, air exchange, internal heat gains, and the use of

solar panels, ventilation units, heat pumps and cooling systems. The program calculates the

energy balance of the building by comparing the emitted energy (cooling,ventilation, infiltration,

transmission) with the supplied energy (heating, solar irradiation, heat recovery, internal heat gain

and electricity).

EcoDesigner uses the same simulation kernel as the VIP Energy product, which is validated with

the following tests (listed in order of complexity):

• EN-15265: The test method for European standard for energy calculations according to

EN-13790.

• IEA-BESTEST: The original for all tests for basic functions of the most important factors

in energy calculations.

• ASHRAE-BESTEST (ANSI/ASHRAE Standard 140-2001): Similar to IEA-BESTEST, with

additional free floating test procedures.

• StruSoft-BESTEST: An in-depth validation method inspired by HVAC-BESTEST,

developed for passive buildings.

7. Energy Balance Evaluation Report

The EcoDesigner Energy Balance Evaluation sheet may be printed or saved in PDF format.

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Picture 8.: Project Key Values and Energy Consumption evaluation

The Evaluation sheet’s Key Values section displays the evaluation date, and basic information

such as project name, location and activity type, as specified by the user on the first tab page of

the EcoDesigner dialog box. The total tempered floor area and ventilated building volume values

are also listed here, along with the outer heat capacity of the building shell. Outer heat capacity

measures the capacity of building structures to store heat against changing outside air

temperature: that is, the resistance close to the surface that helps to reduces energy fluctuations

through the structure. Also in the Key Values section, the minimum and maximum average heat

transfer coefficient values of roofs, external walls, basement walls and openings are displayed, as

determined by the U-value calculator.

The Energy Consumption pie chart graphically displays the percentages of used energy sources

(gas, propane, oil, wood, coal or electricity), alongside a table listing the annual total and specific

quantity and price of each energy source consumed.

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Picture 9.: Carbon Footprint information and the Monthly Energy Balance bar chart

The Carbon Footprint index provides information on the carbon dioxide emissions resulting from

operating the building over the course of a year. The area of tropical forest required to absorb this

carbon dioxide quantity is also displayed for comparison.

The Monthly Energy Balance bar chart is a graphical display of the amount of energy the building

emits (top part of chart), as well as the amount of energy it absorbs from the environment and its

own internal heat sources (bottom part of chart). The Emitted energy and Supplied energy bars

must be equal every month. The vertical axis of the chart shows an energy scale, while the

horizontal axis shows the months of the year. To the right of the diagram, the components that

make up the bars of the chart are listed. The number and type of these components depend on

the data entered for the building’s MEP systems.

8. The EcoDesigner Advantage

EcoDesigner enables architects to differentiate themselves from the competition by offering their

clients:

• sustainable designs that employ ecological thinking from the very beginning of the design

process

• better prepared and better supported design proposals

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• eventually, low energy-use buildings that optimize operational costs by minimizing energy

consumption.

These can be key factors in winning new jobs in both the private and public sectors. At the same

time, the “carbon footprint” consequences of designs highlight the importance of conserving

nature’s resources.

For more information about the Graphisoft EcoDesigner solution, including tutorial movies

explaining the workflow, visit the official website at:

http://www.graphisoft.com/products/archicad/solutions/ecodesigner.html

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