Modifiers

Modifiers allow water- and air-side component properties to alter based on a function or on a schedule.

For example, modifiers can be used to set a temperature reset option on a boiler. They can also be used to set up the partload efficiency of a chiller.

The modifiers can be found by double clicking on a component. There is a tab for each property that can be modified.

When an hourly modifier is applied to a property, it replaces the property’s value with a table of values based on day type and hour of the day.

When a yearly modifier is applied to a property, it replaces the property’s value with a table of values for each hour of the year.

When a schedule modifier is applied to a property, a schedule is applied which switches the property between its value and a setback value.

Table and curve modifiers can either be used to replace a property’s value (when set to “=”) or used to alter it (when set to the mathematic operations “+”, “*” and “/”).

Multiple “+”, “*” and “/” table and curve modifiers can be used on the same property.

Some components can only have “+”, “*” and “/” table and curve modifiers applied to them, such as the duty of a chiller.

A table modifier allows you to set the modifier as a function of parameters such as outdoor dry bulb temperature. The function is entered as a table. For example, the temperature reset on a heating circuit can be modelled by adding a “=” table modifier onto the setpoint of the boiler and setting the modifier to be a function of outdoor dry bulb temperature.

By clicking the “Axis” button in the table modifier dialog, you can have the modifier alter as a function of up to 3 parameters.

Curve modifiers allow you to set the modifier as a function of parameters such as outdoor dry bulb temperature. This function is entered as a polynomial and you can select the type of polynomial as well as the value of its constants.