As carbon dioxide levels rise, it indicates that the ventilating system is malfunctioning or the design occupancy
of the room is being exceeded.
oz-design] is determined by Equation 1 and using Pz at the design occupancy
This replaces the usual high flow based on maximum design occupancy
In addition, as it is costly and difficult (but not impossible) to estimate accurately the actual occupants in each space, the standard procedure is mostly based on the design occupancy
profile, leading to over-ventilate the spaces yielding less than design occupants and consequently waste of energy.
Relative to design occupancy
levels versus actual real-time occupancy, we have two observations.
In fact, the air flow required for design occupancy
is often supplied even when conference rooms are unoccupied, when no ventilation is needed because terminal box control does not commonly use even motion sensors to detect the presence and absence of occupants.
The airflow rate per square foot of building floor area is based on the design occupancy
density and the required flow rate per person, adjusted to reflect the air-distribution system used.
demand control ventilation (DCV): a ventilation system capability that provides the automatic reduction of outdoor air intake below design rates when the actual occupancy of spaces served by the system is less than design occupancy
For all DCV systems in this study design occupancy
was used to determine ventilation rates as the minimum OSA level, contrary to the theory of DCV.
An HW has appreciably greater value for a DOAS serving spaces with high design occupancy
levels than for spaces with lower design occupancy
levels because the higher OA volumes required for the high design occupancy
spaces have a greater potential to over-cool spaces at off-peak conditions.
The design occupancy
values are used strictly for determining the ventilation requirements discussed later in this paper.
Since the amount of outdoor air determined by MSE is based on the design occupancy
, this amount could be more than required based on the actual occupancy.