7/12 Schedules - Defined Using Profiles

General tab on Schedules Dialog.

 

7/12 Schedules reference Profiles of daily variation, one Profile for each day of the week and for each month of the year (hence 7/12).

 

You can select multiple rows (months) or columns (days) and edit the data by clicking on the Edit selected cells link in the Info Panel. Likewise, you can select individual profiles by clicking on the appropriate cell and clicking Edit selected cells.

Design days

Winter and summer design day simulations are carried out when required for autosizing heating and cooling equipment prior to a Compact HVAC simulation.

Design day definition method

With 7/12 Schedules there are 2 ways to define the schedule during these winter design day simulations, 1-End-use defaults or 2-Profiles:

1. End-use defaults

When the End use defaults option is selected you should define the intended use for the schedule using the options below and DesignBuilder controls whether the schedule is active during heating design using the options set on the Heating Design tab of the model options dialog:

 

It is also necessary to apply the behaviour for each category as defined on the Heating design tab of the Model options dialog.

 

Behaviour of the schedule during the Summer design day when autosizing cooling systems is simply taken from the profile for Wednesday, i.e. for any particular month, the schedule has the same behaviour during the cooling design day as it has for Wednesdays.

 

Note that if the schedule is to used for heating or cooling operation then it is especially important to select the appropriate setting.

Warning: This system of categories can be confusing and has been underlying cause of many queries on the DesignBuilder support desk related to undersized HVAC systems. We therefore now recommend that you to use either the 2-Profiles option where the schedule operation during heating and cooling are defined explicitly using a profile or use Compact schedules where again heating and cooling design operation is defined explicitly.

2. Profiles

In this option both heating and cooling design day operation are defined explicitly as a Profile. This is more flexible and clearer than End-use defaults and is the preferred choice.

 

Important Note: When setting up schedules that will be used in Compact or Detailed HVAC simulations it is important to consider whether the schedule will be active or inactive during the heating and cooling sizing simulations used for autosizing equipment. Generally internal gains must be excluded from heating sizing. So you should make sure to select the "Off" schedule for the Heating design day profile if the schedule is to be applied to internal gains, occupancy, lighting etc.

Tip: It is normally important to use different schedules for different types of schedule. For example don't try to use the same schedule to operate internal gains and the heating system because the gains need to active during the heating design day and the heating should not.

Weekly and monthly variations

Other tools are available for rapid selection/de-selection and setting of schedule data:

 

 

 

See also EnergyPlus Compact Schedules