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# What is the Relations between Occupancy and Activity schedules

Could not find any documentary on the relations between Occupancy and Activity schedules. If there is any please direct me to the documents. I Find out the hard way that occupancy schedule must be a fractional schedule and I assume for load calculation OS uses the product of the zone multiplier, occupancy and activity schedules. In that case activity schedule should hold the max human load for different times? Is that correct?

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Since OpenStudio ultimately creates EnergyPlus files, it is best to read the EnergyPlus Input / Output Reference documentation regarding specific input fields. Occupancy schedule and activity schedule are both inputs for the People object. Occupancy schedule sets the portion of the peak occupant number that are within the zone for different times during a simulation. Activity schedule sets the heat generation from occupants in the zone in units of Watts per person. These are typically constant values, and you can see a table of acceptable values for different activity levels (standing, walking, etc.) in a table a little below the activity schedule input field.

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Hi Aaron thank you for this detailed reply. Does that mean the occupancy in the openstudio template is for calculate the maximum occupant number which is for load calc, terminal unit sizing like VAV; while the occupancy schedule is another daily varied diversity factors that will only be used when we do the large system sizing like chiller plant? If so, even we get another occupancy schedule profile, it won't be taken into energy modeling final results. I noticed that the default fraction some for occupancy schedule is like 0.5 which make a large difference if we enable this to do load calc

( 2021-03-23 12:59:23 -0500 )edit

@Brianna there's a peak occupant density you define as a people definition (people per area, e.g.) in the Loads tab. The occupant schedule is then multiplying that peak occupant density by different fraction values over the simulation to account for changes in the number of occupants. This certainly changes load calculations for zone units (VAV terminals) and central systems (chiller plant), as you mentioned. Note that there is a different occupancy schedule that can be applied to summer/winter design days for sizing HVAC equipment separately from the run period (annual simulation, e.g.).

( 2021-03-23 18:04:12 -0500 )edit

Thank you Aaron so if the diversity factor is 0.8 we will go to add a constant schedule of 0.8 fraction

( 2021-03-24 15:28:13 -0500 )edit