Occupancy

Activity tab in model data

The Occupancy model data defines the number people in the space and the times of occupancy. This data is used in Simulations and Cooling design calculations together with the Metabolic heat output of the occupants and Holidays to calculate the heat input to the building.

The Occupancy timing settings may also be used to control internal gains and/or HVAC systems depending on the Model option settings.

Occupancy density

When the Occupancy method is set to 1-Occupancy density you can set the number of people per unit floor area. It is usually most convenient to load this data from the Activity template.

Floor area per person

When the Occupancy method is set to 2-Area per person you can set the floor area per person, i.e. the reciprocal of the occupancy density above. You must check the Occupied checkbox first.

Number of people

When the Occupancy method is set to 3-Number of people you can enter the number of people in the zone directly. In this case note that the value entered at block and building level does not normally inherit very effectively, especially in buildings with zones of very different floor areas. In this case enter the number of people for the most common type of zone at building level. Unless you need to enter specific numbers of people in each zone this option is best avoided as it increases the amount of work involved due to the inheritance mechanism not working effectively for gains that are not normalised by floor area.

Timing

The way that Occupancy is scheduled depends on the Timing model data option as described below.

Typical workday timing model option

 

When the Typical workday Timing model option is set, the occupancy times are controlled by setting On and Off values and the number of days in the working week.

 

 

In above example there are 0.2 people per m2 between 8am and 6pm and there are no people outside these times and at weekends.

Note: The Occupancy Days / week is set at the building level only and is used for all other Typical workday schedules in the model apart from Mechanical ventilation, and Heating and Cooling operation which have their own Days / week data.

Schedule timing model option

 

When the Schedule Timing model option is set, the occupancy times are controlled by a Schedule . The metabolic gains for the zone are multiplied by the value of the Schedule at each time step in the simulation so you can define periods of part-occupancy using Schedule values less than 1. Use values of 0 to indicate that the space in unoccupied.

 

 

In above example number of people per m2 is calculated as 0.02 xSchedule value.

Latent fraction

Occupancy latent gains account for moisture from people in the building due to both perspiration (sweating) and from exhaled moisture. The way that latent gains are calculated depends on the Occupancy latent gains model option.

When this option is set to 2-Fixed fraction then you can enter the latent fraction here. A typical default value is 0.5. Alternatively if this setting is left as the default 1-Dynamic calculation option then the latent fraction is calculated within EnergyPlus at runtime based on internal temperatures and metabolic rate and no additional setting is required here.