Installation of CO2 sensor to Improve Indoor Air Quality (IAQ)

What is Carbon dioxide instrument ?

Carbon dioxide sensor (CO2) sensor is used to measures CO2 concentration within conditioned/ unconditioned or in outdoor environment. The measuring unit is ppm (parts per million). 

Properties of CO2:
- Invisible
- Odorless

Measuring principle: CO2 sensor works on 
- NDIR : Nondispersive Infrared (it is is a simple spectroscopic sensor often used a gas detector)
- Chemical CO2 Sensor 

Effect of CO2 sensor:
- Fatigue 
- Reduced concentration for humans.

Change in pressure and temperature affects the CO2 concentration. 

Most commonly, CO2 sensor is used to improve indoor air quality in air-conditioned spaces. CO2 sensor is installed in the return air duct to measure the concentration of CO2 and then based on measurement it controls the Outdoor Air Damper (supply of fresh air to maintain indoor IAQ level within the space). This is also called Demand Control Ventilation (DCV), as per demand ventilation is controlled with the help of Building Management System (BMS). Below Figure shows that CO2 is recorded and then fresh air intake is adjusted as per the level of CO2. 


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