Smart CO2 measurement improves the indoor climate in everyday office life 

One of the com­pe­tence lead­ers in the field of secu­ri­ty around heat­ing and tank sys­tems is the fam­i­ly-owned com­pa­ny AFRISO. In this tra­di­tion, the smart home sen­sors ensure more safe­ty, liv­ing com­fort and a good indoor cli­mate in build­ings. The com­pa­ny offers a wide port­fo­lio of sen­sors and actu­a­tors for this pur­pose. How easy it is to mon­i­tor and specif­i­cal­ly improve the indoor cli­mate in office build­ings is shown by the lat­est appli­ca­tion exam­ple of a com­pa­ny in the Heil­bronn district. 

CO2 sen­sors can be ide­al­ly used for tar­get­ed ven­ti­la­tion mea­sures. In view of the Coro­na pan­dem­ic, this wish was also expressed by a com­pa­ny in the dis­trict of Heil­bronn in Baden-Würt­tem­berg. The goal of those respon­si­ble for occu­pa­tion­al safe­ty and build­ing ser­vices was to con­tin­u­ous­ly mea­sure the CO2 con­cen­tra­tion in the indi­vid­ual rooms and, if thresh­old val­ues were exceed­ed, to inform the employ­ees and at the same time encour­age them to take suit­able ven­ti­la­tion mea­sures. With the effi­cient sys­tem, an effec­tive solu­tion could be imple­ment­ed with­out fur­ther ado, which also gives oth­er respon­si­ble per­sons in the com­pa­ny insight into the cur­rent situation. 

For this pur­pose, a CO2 sen­sor was sim­ply installed in the exist­ing sock­ets at sight lev­el in each of the indi­vid­ual office and meet­ing rooms. Since the CO2 con­cen­tra­tion is dis­played direct­ly on the sen­sor with an easy-to-under­stand LED traf­fic light and the sen­sor is already in stand-alone oper­a­tion, the employ­ees were imme­di­ate­ly able to imple­ment the ven­ti­la­tion rec­om­men­da­tions. If the LED is green, the car­bon diox­ide con­cen­tra­tion is less than 1,000 ppm (parts per mil­lion, equiv­a­lent to 0.1 per­cent). When yel­low, this rec­om­mend­ed lim­it is exceed­ed. A red LED indi­cates a con­cen­tra­tion of over 1,500 ppm, then it is high time to ven­ti­late. As soon as the traf­fic light returns to green, enough fresh air has flowed in and the win­dows can be closed. 

To ensure the best pos­si­ble wire­less con­nec­tion in the smart home sys­tem, the appro­pri­ate ranges in the build­ing were mea­sured in advance. This allowed the home gate­ways to be installed and inter­con­nect­ed at defined points. Thanks to EnO­cean® wire­less tech­nol­o­gy and the “device-in-device” func­tion of the AFRISO­home app, no cables had to be laid or oth­er struc­tur­al changes made. 

Using the autho­riza­tion con­cept avail­able in the app, pro­grams could be cre­at­ed for indi­vid­ual users that send a push mes­sage to their smart­phone or — for PC users — to the AFRISO­home web app when the thresh­old val­ue of 1,000 ppm CO2 is reached. As a result, employ­ees are now prompt­ed to ven­ti­late with a push mes­sage in addi­tion to the orange LED. 

In this project, approx­i­mate­ly 20 gate­ways and over 100 CO2 sen­sors were installed. By link­ing the gate­ways to a mas­ter gate­way, addi­tion­al thresh­olds with push mes­sages to super­vi­sors were imple­ment­ed. All mea­sured CO2 val­ues are stored in the respec­tive gate­way for about four weeks and then over­writ­ten by the new data.