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

@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.).

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