Demand Control Ventilation Q & A
How many sensors are required in a typical installation? Where should they be located?
The number of zones with different occupancy patterns should dictate the number of sensors. In a small office application for example, it would be ideal to have a sensor in the office space and one in the conference area. Carbon dioxide distribution in a space is influenced by the same factors that influence temperature distribution. These factors include convection, diffusion and mechanical air movement. Much like temperature sensors, placement of CO2 sensors should be based on the zone to be controlled and anticipated loads (e.g. common occupancy density and patterns). For optimum control, there should be a CO2 sensor placed in every location where temperature controls are used. If an HVAC system is serving a series of zones with similar occupancy patterns, sensors placed in the return air ducting may be appropriate.