In most commercial occupied buildings, ventilation is provided to deal with two types of indoor pollution:
(1) odors from people
(2) off-gassing from building components and furniture
In addition to these, higher ventilation is also linked to higher cognitive abilities and productivity and showcase in this Harvard study.
For many types of medium to high-occupancy spaces, such as classrooms, multipurpose rooms, theaters, conference rooms, or lobbies have ventilation designed for a high peak occupancy that rarely occurs. As a result, ventilation can be reduced during the hours of operation when spaces are vacant or at lower than peak occupancy. When ventilation is reduced, building owners and operators save energy because it is not necessary to heat or cool as much outside air.
With Cove.tool, 3 types of ventilation control strategies can be simulated for the projects:
// 1 Demand Control Ventilation
Demand Control Ventilation (DCV) enables 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. The system is controlled by sensors measuring the number of people or indoor air parameters or adapted criteria (e.g. CO2, mixed gas or VOC sensors).
Typically In colder climates the heating for ventilation air is greater and DCV saves the most energy.
// 2 Always On
As suggested by the name, the ventilation will always be on with this option. The fan energy would be higher with this option as it is not adjusted based on the building occupants.
// 3 Off During Unoccupied Hours
With this option, the ventilation system will be 100% operational during the active occupancy hours of the building and it will be switched off when it is unoccupied. The ventilation rate would be a constant designed rate since it doesn't vary based on the occupants.
The impact of the control type on the air flow is calculated according to the standard EN 15242.
Picking the Always On or Off During Unoccupied Hours is expected to be better at coping with challenges created by COVID-19.