EcoDesigner

Isler House in New Zealand. Architect: Dave Chisholm

Isler House in New Zealand. Architect: Dave Chisholm

EcoDesigner

EcoDesigner is an add-on to ArchiCAD that enables the leveraging of data from a building information model for a topic of current interest: evaluation of the energy consumption and energy conservation of a building. This article first discusses the work process used with the program and then comments on a trial run.

With EcoDesigner, architects are now able to assess the energy economy of a building in a feasible way. The program quickly performs an analysis on an ArchiCAD building information model, yielding a variety of valuable data that tell the designer how his design solutions affect the building’s energy consumption, overall costs and carbon footprint.

The best thing about EcoDesigner is how broad its analysis is. The program looks at the design as a single object which is affected not only by the building components but also by the location of the building, local weather conditions, how the energy it uses is produced and many other parameters that can be set for the analysis. Rapid testing of a design makes it easier to tweak the design to make it more ecological; the impact of any change can be instantly viewed in EcoDesigner.

The program is built on the VIPCore calculation engine from Strusoft of Sweden, based on certified analysis standards in the field. The calculation is so quick because certain parameters are calculated on the basis of default values. EcoDesigner thus does not purport to replace or even compete with more detailed analysis programs, which have their uses. For the architect, however, the benefits of this program are clear; its ease of use makes it a useful tool for anyone who needs to evaluate the energy economy of a design.

Operating process

The use of EcoDesigner is divided into three phases: analysis, calculation and reporting. First, of course, we need a source for the analysis – a model of the building being investigated. A normally diligent and systematic approach in building the data model is sufficient for an EcoDesigner analysis. Here are some self-evident rules: the building components must be made with the tools intended for them: walls with the wall tool, slabs with the slab tool, etc; structure types must be consistently chosen and the joins between structures must be modelled accurately, leaving no cracks between walls or any other structures.

Analysis

design menu

EcoDesigner is accessible under Design Extras in the Design menu

EcoDesigner is accessible under Design Extras in the Design menu; when selected, the program automatically performs an analysis on the structures and divides them into exterior and interior structures. It is then recommended to select Model Review in the Structures tab; the colour coding will show you whether the analysis has been correctly performed. At this point, you can change the classification of building components by selecting a component and changing its colour. Once the analysis is correct, enter the data required for calculation.

analysis_house

The building shell elements and the interior structures are analysed.

Entering the calculation parameters

The program requires a wide range of inputs during its first run; however, once this is done, making the changes required to get results from a model is quick.

Location and purpose definition

The location and purpose of the building are defined on the first tab.

First, determine the location and purpose of the building. Select a city from the list or enter the longitude and latitude of the site. The program retrieves weather data from the Internet on the basis of these parameters. You also need to determine the orientation and height of the building, wind shielding, the nature of surrounding surfaces and shading against the sun. These may be provided as numerical values or by choosing from a number of preset parameters.

Select the heating profile by selecting a purpose for the building in the list provided. You can create a new purpose if a suitable one is not available or if the building has several purposes. The preset purposes include housing, teaching premises, office premises, hospital premises, commercial premises and a variety of industrial premises.

structure values before fine-tuning

Structure values before fine-tuning. The program assigned certain values which had to be tweaked for all structures. A yellow triangle denotes a struc- ture to which the program could not assign a value. A 3D view of the analysis is available by clicking on the Model Review button.

The appropriate U-values and other values can be assigned to the structures on the Structures tab. Structures are divided according to orientation. If the model has consistently selected structure types, this phase is relatively simple due to ease of identification and the reasonable number of structure types involved.

u-value_override

The U-value calculator window opens from the button next to the U-value field. If you choose ‘override’ the U-value of the whole structure can be assigned directly.

To reassign U-values, open the U-value calculator window, where you need to enter the thermal conductivity, density and heat capacity of the structure or filling. These parameters may be found in the technical specs provided by the manufacturer or in generally available tables. If the calculator returns a result that does not look right, you can further tweak it by adjusting the heat transfer coefficients and thermal bridge effect at the bottom of the calculator window.

Next, you need to specify the properties of the openings: shading device, glass % of surface area, U-value, total solar transmission (TST) and infiltration. Openings, like structures, are divided according to orientation. The parameters for each type of opening can be adjusted separately. Parameters can also be imported from preset building component lists in the library. The shading device is selected from a list of presets for various blinds and external shadings.

Finally, the MEP systems and energy sources need to be specified. Select an appropriate type for cooling, ventilation and heat recovery from the presets. Numeric values for capacity or efficiency can be entered to fine-tune the selection. If the building has a heat pump or solar panel(s), their properties must be separately specified.

Heating and other energy consumption must be entered as percentages and costed according to local energy costs.

Analysing the building

EcoDesigner automatically analyses the building, dividing the building components into exterior and interior structures.The colour coding makes it easier to verify the analysis. You can change the classification of building components using the functions on the Model Review palette.

openings U-values

The U-values for openings can be entered directly in the relevant column. Shading devices are also selected here for each opening type.

mep_systems

The properties of MEP systems and energy sources have a huge impact on overall energy consumption and the carbon footprint.

green_energy

Values for solar collector, air to air recovery and heat pump are now under the Green Energy tab.

Report

Once all values have been entered, click Start Evaluation. The program performs the calculations in a few seconds and generates a report. The basic data included in the report are the floor area and volume of the building, its heat capacity and the U-values of the external shell structures.

Under energy consumption, the report itemises the percentages and costs of the various energy sources, as annual value totals and per square metre. The carbon footprint is calculated as tonnes per year; this is determined according to the energy sources selected.

The final table in the report is the monthly energy balance, showing heat generation and heat loss in different colours.

The report is saved in PDF format. The impact of changes made during the design process can be quickly evaluated by generating a new report after each change. It is worth saving the various options explored in combined layers in the model, which makes it very simple to replace a layer combination and then recalculate. Logical naming of the reports generated for each option makes it easier to compare versions of the design.

EcoDesigner Report

EcoDesigner can generate a report on the model in a matter of seconds. The tables and graphics make the data easy to read.

Testing experiences

In writing this article, I tested EcoDesigner using a model of a simple four-storey office building which I made for this purpose. The building was a rectangular twin-corridor office block whose external dimensions were 53 m by 17 m. The building was equipped with mechanical intake and exhaust ventilation.

The most laborious part of the process is entering the values and structural parameters required for the calculation; but once this has been done, changing the model and immediately evaluating the changes with EcoDesigner is easy and quick. Entering the values is simplified by the fact that the program offers simple presets for about half of the values required. Every value entered affects the end result. The U-values and infiltration of the structures are of course important, but properties of the environment such as shading and wind shielding also affect the results. The MEP systems used in the building have a significant impact.

Entering U-values for the walls is something of a challenge, since the program uses a U-value calculator requiring entry values that need to be found from the appropriate sources. In this case, I used specs provided by insulation manufacturers and found the remaining values in the tables in the local builders’ calendar.

Using values consistent with current regulations, the average energy consumption of my sample building was about 150 kWh/m2.

Changing the orientation of the building from east–west to north–south added 3 kWh/m2 to the energy consumption. Shading windows on the outside and inside each reduced the energy consumption by 1 kWh/m2.

Energy sources have a huge impact on the carbon footprint of a building. Even if energy consumption within the building is radically cut, the building will still have a considerable carbon footprint if the energy used is generated using fossil fuels. The carbon footprint can be reduced to zero in this program, for instance by heating with electricity generated by nuclear power. The downside is that electricity makes this heating option more expensive which shows in the energy costs.

The principal impression gained from using the program is that the evaluation of changes made to the model was quick and easy. In regular use, a designer will most probably quickly acquire a library of the most commonly used structure types and defining new ones poses no problem if the information is to hand.

In the latest version of the EcoDesigner there is a good practical improvement. Earlier the structure’s U-value was calculated from the structural layers. The calculator is still in use, but it can be overridden by putting the U-value directly in the U-value field. U-values are commonly given for the entire structure in the case of external shell structures such as walls and roofs; input with this logic is now possible.

ECODESIGNER

Further information about EcoDesigner:
Sved, Miklos (2009) Advanced GRAPHISOFT EcoDesigner User Guide.
Available at the ArchiCADWiki

Thoo, Sid (2010) Graphisoft EcoDesigner. AECbytes
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This article was originally published in ArchiMAG 1/2010 and was written by Vesa Putkonen

Written by Vesa Putkonen

Comments
3 Responses to “EcoDesigner”
  1. Gopi says:

    Hola, te agradeceria me cmneotes si sabes algo sobre la salida del plugin para poder usar maxwell render 2.5 en archicad 15.saludos.CDA.ami tambien me intresa saber algo sobre el plugin para maxwel render 2.5, saludos y graciasSaludos a ambos, CDAXXX y Luis Mario, he estado buscando alguna noticia sobre maxwell render y ArchiCAD 15 pero no encuentro nada al respecto. La pe1gina oficila de Maxwell Render habla de la compatibilidad de su producto hasta ArchiCAD 14 sobre Mac, Windows a 32 y 64 bits, pero nada sobre ArchiCAD 15

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