Creating Multiple Scenarios

In case users need to create customized modifications to the properties generated by CEA Toolbox with the statistical archetype database, this section will provide the required instructions.

In this topic:


Modifying building properties

In this section, the user will learn how to change the properties of the simulation model. As an example, we will use the age.shp shape file, however, other properties e.g. occupancy, supply systems can be changed in the exact same fashion.

To see how changing properties work, follow this example:

  • Locate age.shp under the building-properties folder within inputs
 
  • Drag age.shp into the viewer to open it
  • In the table of contents, it appears the scene layer age
  • Right click on it and select ”Open attribute table”. The following window will appear, which shows the age of the inauguration of each building, as well as the age of retrofitting of each of its components.
  • Find this “3D editor” in the toolbar located at the top side of the window. If you cannot find this "3D editor", right click on anywhere of the toolbar at the top and select "3D editor".

  • Click on “3D editor” and select ”Start Editing” in the dropdown list.

 
  • Now, the user can double-click on any of the emission type that needs to be modified.

  • When finish editing, click on “3D editor” again and select ”Stop editing” in the dropdown list. Modifications will be automatically saved after "Stop editing".

  • After making all the modifications, the user can start running the simulation again, using the Data helper as a starting point.


Creating a new geometry

In case you would like to add your own geometry. The following steps need to be followed:

Draw urban area on CAD

  • Draw your buildings cluster or urban area on a CAD software, such as AutoCAD. The footprint of each building should be drawn individually, as a closed polyline, with no overlapping lines between buildings.

Note: In case you have any building with varying heights inside its footprint, the building should be drawn as a group of buildings of different heights, as in the following example:

Convert CAD file to a shapefile using ArcCatalog

  • Connect to the folder containing your CAD file, right click on your file and select Export > To Shapefile (multiple), as follows:
  • Select which features you would like to use (e.g. for building shapes, select Polygon), select an output folder and click Ok. A similar image to the following should appear:

Check shapefiles

  • Open shapefiles using ArcScene and check if they have been modeled correctly.

Note: you still need to create a shapefile for each required CEA input file and input your data into the corresponding attribute tables.


Scenario modification examples

Scenario 1: Changing building age

By changing some of the data in the attribute table of 'age.shp', the user can simulate a scenario of retrofitting a group of or all the buildings.

  • Same as at the beginning of this chapter - open the attribute table of 'age.shp'. The following window will appear:
  • Start editing.

  • Modify the year of “envelope” or “roof” or “windows” or “partitions” or “HVAC” as needed.

  • Stop editing and run the simulation again.

Scenario 2: Changing building occupancy

By changing some of the data in the attribute table of “occupancy.shp”, the user can simulate a scenario of changing the occupancy of some or all buildings.

  • Same as at the beginning of this chapter - open the attribute table of “occupancy.shp”. The following window will appear:
  • Start editing.

  • Modify the percentage of each function(s) of each building as needed. If the building only has one function, then put "1"; if the building is mixed-use, type in the share of each function. Please note that the sum of the shares of all the functon of a buildng should be equal to 1.

Scenario 3: Changing building supply systems

By changing some of the data in the attribute table of "supply_systems.shp”, the user can simulate a scenario of changing the supply systems of some or all the buildings.

  • Same as at the beginning of this chapter - open the attribute table of “supply_systems.shp”. The following window will appear:
  • Start editing.

  • Modify the type of “type_hs” or “type_cs” or “type_el” or “type_dhw” as needed. hs=supply of heating system; cs=supply of cooling system; el=electricity supply; dhw=domestic hot water supply.

Scenario 4: Changing building components' U-values

By changing some of the data in the attribute table of 'thermal_properties.shp', the user can simulate a scenario of changing the U-values of some or all the buildings.

  • Same as at the beginning of this chapter - open the attribute table of “thermal_properties.shp”. The following window will appear:
  • Start editing.

  • Modify the "U_base" or "U_roof" or "U_win" or "U_wall" as needed.

Scenario 5: Changing building HVAC systems

By changing some of the data in the attribute table of “technical_systems.shp”, the user can simulate a scenario of changing the emission systems of some or all buildings.

  • Same as at the beginning of this chapter - open the attribute table of “technical_systems.shp”. The following window will appear:
  • Start editing.

  • Modify the type of “type_cs” or “type_hs” or “type_dhw” or “type_ctrl” as needed.

Scenario 6: Changing weather files

  • In order to add another .epw weather file, first, you would have to locate the main CEA folder on your PC/laptop. To do so, right-click on the CEA Toolbox plugin on the catalog panel, then choose Properties:
  • The following window should appear:
  • Copy the location of the file, but make sure to only copy the location without choosing the file name, as shown in the following example:
  • Paste this link in your windows explorer. Then a similar window to the following should appear:
  • Find the Weather folder. To do so, go to cea > databases > CH > Weather, you should land in a folder with a number of weather files, such as follows:
  • Paste in this folder the desired weather files, and they should be automatically added to the list. To make sure they are added correctly, make sure ArcScene is closed while you are copying the files.