A fresh air contains approximately 400 ppm of CO2 and in an average room a concentration of CO2 reaches a double value already within an hour. This is valid at residing of 1 person in rest. If there are more people in a room, who moreover do some physical activity, then to keep an air quality it is necessary to exchange an air volume in a room even a few times per hour. 1000 ppm is considered to be a maximum acceptable value for a long-term residing, while 700 ppm is a limit for a fresh air feeling. At higher concentrations, a lassitude and sleepiness appears and a high CO2 concentration can lead to chronical difficulties. From the above-mentioned example, it´s easy to imagine how quickly can be the air unhealthy, for example in a poorly ventilated office. Naturally, the biggest enemy of a sufficient ventilation is increasing of expenses for heating and air conditioning.
Advantages / Features:
The ready-made module Figaro CDM4161a is very suitable for monitoring of indoor CO2 concentrations. It is able to measure the CO2 concentration in a 400-4000 ppm range, what responds to an output voltage of 0.4 to 4 V. At the same time, the module has a „Control“ output, which changes its status to High after exceeding of 1000 ppm and it is suitable for example for a direct ventilation control. CDM4161a is maintenance free, pre-calibrated from production, but it also has a possibility of „recalibration“ – after applying a High level on the Reset input (setting of 400 ppm).
CDM4161a can be used for ventilation control, but even for a visual inspection – in conjunction with an indicator or similar. At the end, such a solution brings savings of expenses for energies (heating/ air conditioning) and mainly it increases the indoor air quality.