2023-03-03 05:26 PM - edited 2023-03-06 10:32 AM
In this article we want to give you an overview of the workflow with Energy Evaluation and EcoDesigner STAR. The article will not describe every step of the workflow in detail, but will focus on best practices and guidelines and aims to give the overall picture.
The aim of energy analysis is to help decision making in the early design phases of the projects by calculating the primary energy demand of the building. Energy analysis can be an integral part of the design process that helps architects to keep control of the building’s energy performance. It also helps architects see what impact design decisions have on the energy performance of the designed building. Early design choices, such as:
already mostly determine the future energy efficiency of the building. For this reason, it is crucial to use this workflow already in the schematic and early design development phases of the projects to support or challenge certain design decisions. Later project phases may require other methods of energy analysis calculations usually executed by energy expert engineers using a different software package.
Energy analysis focuses on and helps reduce the energy consumption of the building during its operational phase and does not deal with the energy consumption during raw material acquisition, manufacturing, construction, reconstruction, and demolition.
Life Cycle Assessment (LCA) calculations can also be part of the evaluation of the building’s environmental impact. The plugin for Archicad, named DesignLCA, developed by Graphisoft Center Danmark is a tool developed for Archicad users to help with LCA calculation. Read more about the plugin here.
Standards, legal regulations and building codes to consider during the evaluation vary from country to country.
In the European Union, Energy Performance of Buildings Directive (DIRECTIVE 2010/31/EU of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings; latest modification: 01/01/2021) is operative. From 2020, all new buildings must be nearly zero energy buildings (nZEB). The definitions of nZEB vary by member states.
Goals of the energy analysis workflow:
It is not the goal with the Archicad-based energy evaluation to execute or document calculations required by energy certificates or calculations of future, factual energy consumption of the designed building, because EcoDesigner STAR is not an energy audit tool.
Energy Evaluation and EcoDesigner STAR are the same add-on built into Archicad. Energy Evaluation is free, available to everyone who has an Archicad license but not offering all the functions. EcoDesigner STAR is the fully functional version of the add-on only available to Forward/SSA subscribers.
We want to give you guidelines and best practices for modelling and model checking in this section.
1. Set up Project Preferences
Set up the following as per the BEP (BIM Execution Plan) of the project (these should be set up in the project template first). See Location Settings.
2. Start a dedicated Archicad project file
Work in a separate Archicad model dedicated to energy analysis. We recommend this because several modelling guidelines are different from what is generally advised during the architectural design. It is best to separate a project file from the primary model of the project after all necessary, project specific parameters/settings have been added/adjusted in the main project file.
3. Prepare the file for the energy model
The dedicated Archicad project file needs to be prepared to help working with the energy model:
4. Follow the modelling guidelines
General Settings for Energy Evaluation
5. The Energy Model Review Palette
Start using the Energy Model Review Palette for model checking and the next steps of the workflow.
Design > Energy Evaluation > Energy Model Review
1 - Three tabs for the main components of the BEM (Building Energy Model): thermal blocks, structures and openings
2 - List of thermal blocks / structures / openings of the BEM
3 - Properties of the selected thermal block / structure / opening
4 - Energy model visualization and update options
5 - Data input
6 - Energy simulation and export
6. Model checking
Check your model by visualizing it. See Building Energy Model Visualization
Additional Data Assignment and Input
This step of the workflow means defining/setting up/checking/adjusting additional data that is relevant in the energy simulation:
Note: update the zones of the model after any changes applied to them. Also update the energy model after changes in the model or in the data added (discussed in the section above, in STEP 2).
Automatic Model Geometry and Material Property Analysis
1. Automatic BEM generation by Archicad
Archicad analyses the model, the building elements’ material properties, and all the other data that has been added in the previous step. As a result of this analysis, Archicad automatically generates the BEM with the space boundaries. The list of structures and openings are populated in the Energy Model Review Palette.
2. Check thermal properties
The task of the architect here is to check/adjust the thermal properties of the structures and the openings modelled in the previous step (doors, windows and curtain walls) and their thermal properties, such as internal and external heat transfer coefficients (check local standards), U-values, glazing type, shading devices (if any).
3. Solar analysis
Solar analysis should be run as a part of this step of the workflow (always before the energy simulation) to see the solar exposure of the glazed surfaces. Only 3D modelled elements’ shading effect will be shown on the charts.
The energy model and the data in it will be more accurate after running the thermal bridge simulation. (This is an EcoDesigner Star feature.) See the EcoDesigner Star User Manual for details.
The Thermal Bridge Simulation is based on the details of the project, the fills assigned to the Building Materials and their physical properties.
You can add the effect of the thermal bridges in the energy model (even without EcoDesigner Star) on the Structures and the Openings pages of the Energy Model Review Palette.
At this point one round of the analysis has been run. If there is a need for improvement in the energy efficiency, the conclusions, learnings, and suggestions for design changes can/should be implemented in the architectural model. The simulation should be repeated after each major design change and the results should be compared to the baseline building’s results. If there are multiple design options, a separate energy model should be developed for each of them, and the simulation should be run for each of them to see which option is best from the energy efficiency point of view. This way, the energy analysis becomes an integral part of the architectural design workflow and contributes to the quality of the final design. See the workflow diagram below. (Other impacts, such as the suggested changes as the results of the coordination with the structural or the MEP engineer are also signalled on the diagram.)
During later phases of the design development, more accurate calculations are usually needed to make sure that the building will comply with the local energy efficiency requirements. For this purpose, an energy analysis consultant should be involved who performs the analysis using an energy analysis software based on the data we extract from Archicad (in .gbxml format). This also requires the energy model to be updated with the changes to export the model and the data most accurately. If the client aims to build a building that will get one of the current green building ratings, (such as LEED, BREEAM or Passive House), the energy expert needs to be involved from the very early stages of the project.
To see the full list of features available in Energy Evaluation and EcoDesigner STAR, visit this section of the related article.