Optimisation - Design Variables

Accessed from Parametric, Optimisation and UA/SA Analysis Settings dialog

 

Tip: The Edit Variables dialog should be used with caution because there is no Cancel button, so once the dialog is opened, any changes made cannot be undone and upon closing of the dialog, the variable will be saved, replacing the previous one, with the settings currently being shown on the screen. In the case where you have mistakenly added a variable (or made incorrect changes while editing an existing one) you can close the dialog and then delete the incorrect variable on the design variables tab on the main Edit Parametric, Optimisation and UA/SA Analysis Settings dialog. Alternatively if you haven't made any other changes since opening the main dialog , simply press Cancel on that dialog to lose all changes.

Design Variable

Variable type

Select a predefined or custom variable from the variables browse list.

Important Note: All variable options are listed for selection regardless of the state of the model so care must be taken to select variables that are appropriate. For example, if the Scheduled natural ventilation model option is used then changes in the % External window opens variable (which only applies to Calculated natural ventilation) won't affect results.

Min value

The lowest value that this numeric design variable can take on. This option is only visible when a numeric variable type has been selected (above).

Max value

The highest value that this numeric design variable can take on. This option is only visible when a numeric variable type has been selected (above).

Step (parametric)

Not used for optimisation.

Step (optimisation)

Enter the step between possible variable options. This option is only visible when a numeric variable type has been selected (above).

 

The possible values for the variables are Min value, Min value + Step, Min value + 2 x Step, ... MaxValue. For example if Min value is 16, Step (optimisation) is 2 and Max value is 24, then possible values for this numeric design variable are: 16, 18, 20, 22 and 24.

Options list

Click on the browse button to open a list of components or templates for selection. Items can be selected by checking the appropriate checkboxes. Each item selected will be an option that can be applied during the optimisation process.

 

When a template is selected as the variable type, one of the selected templates from the list are loaded in each iteration of the optimisation analysis.

 

This option is only visible when a list variable type has been selected (above).

 

After the list option selection process has been completed the Variable Option Order dialog is displayed. See below.

List Variable Option Ordering

During the process of using the Options list browse button for selecting discrete design variables, a Variable Option Order dialog appears after selecting the list options to use and closing Select design options dialog. In this Variable Option Order dialog, you can define the order in which the variable options are listed. Depending on the case it may or may not be important to list the options in the right order.

 

If the list of components or templates represents some sort of numerical sequence then it is generally important to set the order of those options in an ascending or descending order, otherwise it is not normally necessary.

 

Target

Target objects

This option allows you to select one or more object(s) to which the variations are to be applied. The object(s) you select here are the places in the model where the variations will actually be applied. Normal model data inheritance rules apply so if you set the building as the target then the change will set for the building but will also inherit down to block, zone, surface and opening levels where appropriate. In this case any hard set data at block or lower levels will prevent inheritance in the normal way.

Tip: For models imported via gbXML any construction or glazing assignments are set in the DesignBuilder model at surface level and so the normal inheritance paths used for construction and glazing will be overriden. Therefore in this case, if you need to parametrically adjust construction or glazing surface properties you may need to apply the changes to each surface individually by selecting the appropriate surfaces as targets.

Key

Variable key

This data is available for variables of the Custom IDF and Custom Script categories. Enter the name of the variable to be used in one or more corresponding DB Erl / EMS <Var, VarName, DefaultValue> statements. The variable key entered here corresponds with the VarName value in the DB Erl script.