In principal there are 2 options where to install the sensors.
In a room close to the occupants or in the ventilation system to detect the CO2 level on outflowing air. The choice is dependent on the nature of space.
Let’s take a hotel as an example.
In the restaurant or a big lobby, a sensor on one wall would most probably misread the other side of the room, a sensor in the outgoing air make more sense.
In a small conference or a regular hotel room a sensor on the wall is sufficient.
There is also a difference between CO2 and temperature sensing and control. You will find temperature being quite even throughout a room. CO2 on the other side can vary from 3000ppm on one end to 600ppm at the other.
When installing sensor controlled ventilation there are a variety of strategies and algorithms to choose from. Depending on who you are: a OEM developer, a system developer or a distributor we need to communicate what strategies you will apply.
A sensor will deliver a signal strength depending on CO2 variables. The frequency of measurements depends on your needs and energy savings (please see our Low Power Platform for wireless installations).
Most likely our sensors end up in PID (for more information on PID see below) controlled systems as they are suitable in multi zone buildings that have high variables and unpredicted patterns of occupancy.
Helpful links PID for dummies
CO2 controls the damper with a set point, when ventilation brings back the right level the sensor closes the damper. This strategy works well in applications like schools, theaters and conference rooms where the occupancy can vary extensively from one moment to the other.
This strategy works with the difference between outside and inside air. The setting point can for example be 100ppm over outside level. As the desired CO2 level is reached the control eases “the gas pedal”.