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 the variable type from the browse list.

 

ClosedView the full list of variable types.

 

Natural ventilation/infiltration

Glazing/shading

Activity/occupancy/comfort setpoints

Constructions

Internal gains/lighting

HVAC systems

Location/weather/orientation

Renewables

Other

Custom EMS

Custom IDF

Custom Script

 

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

Not used yet. This option is only visible when a numeric variable type has been selected (above).

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

After clicking on the Options list browse button to select a list of discreet variable options selecting the options to use and closing the Select design options dialog, you will be presented with a further Variable Option Order dialog where you can define the order in which the variables are listed. Depending on the case it may or may not be important to list the options in the right order. Generally if the list of components or templates represents some sort of numerical sequence then it is important to set the order up correctly, otherwise it generally is not.

 

An example where the options should be listed in the right order is the case where a variable consists of a list of glazing components of incrementally varying U-value. For example the list might consist of 4 glazing systems having U-values 1.0, 1.5, 2.0 and 2.5 W/m2-K respectively. In this case it will help the optimiser to efficiently identify solutions best meeting objectives if you order the list in sequence of the U-values (ascending or descending order).

 

An example of a case where it is less important to list variable options in a particular order is a set of 4 completely different HVAC system templates such as Fan coil units, Hot water radiators with nat vent, VAV and reversible chilled/heated floor. In this case there is no clear sequence and ordering the list is not so important for efficient optimisation analysis.

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.

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.