Control Strategy A critical factor in natural ventilation is the availability of windows that the occupants can open and close at their discretion. However, naturally ventilated buildings often incorporate either high-level windows or ventilators, which are under BEMS control.When under automatic control, the windows must be designed and operated such that:
- The air change rate is sufficient to provide satisfactory fresh air for occupant health and comfort.
- The flow of outside air should be evenly distributed throughout the occupied zone.
- To avoid drafts, local air velocities should be monitored and the windows should be opened/ closed accordingly.
- To avoid rain ingress, wind speed/ direction and rain should be monitored and the windows should be opened/ closed accordingly.
In order to accomplish the above criteria, wind speed/ direction and rain sensors can be monitored by the BMS along with room temperature/air quality sensors. The control algorithms will make a decision as to the window position.