HVAC transmitters and sensor controllers
What is indoor air quality?
IAQ or Indoor air quality is the air quality within and around buildings and structures. It is not merely a matter of how the environment feels (temperature and humidity), indoor air has a direct impact on our health, comfort and wellbeing. Indoor workplaces are found in many working environments such as libraries, offices, sales spaces, hospitals, schools and kindergartens. At such workplaces, no tasks involving hazardous substances are performed. Nevertheless, occupants may feature symptoms belonging to the sick building syndrome (SBS) such as respiratory diseases (e.g. asthma), allergies, burning of the eyes, scratchy throat, blocked nose, and headaches. In the long term this may even cause lung cancer. These afflictions often cannot be attributed to a single cause, and require a comprehensive analysis besides the testing of the air quality. Poor indoor air quality also causes reduced productivity and impaired learning in schools. Common pollutants of indoor air include air pollutants from indoor combustion (cooking, heating), (second-hand) tobacco smoke, moulds, CO, VOC etc…
Why to monitor and control indoor air quality?
The World Health Organization (WHO) and IHME’s Global Burden of Disease study state that globally, about 7 million premature deaths per year are attributed to both indoor and outdoor pollution. Determination of IAQ involves the collection of air samples, monitoring human exposure to pollutants, collection of samples on building surfaces, and computer modelling of air flow inside buildings. Where outdoor air pollution is the subject of long political discussions and differing opinions, indoor air pollution can be tackled quickly.
Source control, filtration, and the use of ventilation to dilute contaminants are the primary methods for improving indoor air quality in most buildings. Modern ventilation systems regulate the indoor air quality based on different parameters, such as temperature, relative humidity, CO2, CO, NO2 and TVOC. These parameters change with the amount of people in the room, their time spent in a room, the outside temperature and the usage of certain pollutants. Together with the increased thermal insulation of our buildings, the importance of intelligent ventilation systems is rising in order to maintain a good indoor air quality and to minimize energy losses.
Avoid contamination via aerosols
The risk of becoming infected with a virus is higher in crowded and poorly ventilated spaces. Spread of a virus occurs often via airborne particles and droplets. Airborne transmission arises through the inhalation of aerosol droplets exhaled by an infected person (e.g. speaking, exercise, coughing, quiet breathing). Transmission of a virus via aerosols rarely occurs outdoors or in large enclosed spaces with low occupancy.
Ensuring proper ventilation can help reduce indoor airborne contaminants. One of the most effective ways to curb disease transmission indoors is to swap out most of the air in a room — replacing the stale, potentially germy air with fresh air from outside or running it through high-efficiency filters — as often as possible. Most ventilation systems are dimensioned to provide crowded spaces with sufficient fresh air. When the room is not occupied, the air volume flow rate can be reduced while still supplying sufficient fresh air. Circulating fresh air helps flush viruses out of vents so they do not build up indoors. However, there is a downside: higher cost and energy use, which increases the greenhouse gases fuelling climate change. Different authorities have different opinions regarding the best and most efficient form of ventilation. Common sense and weighing costs/benefits, both financially and for the climate, therefore remain of great importance.
Visualising IAQ with Sentera Controls
Our sensors offer a simple solution to monitor air quality and generate visual or auditory alerts in case extra ventilation is required. The LEDs provide a clear visual indication of the indoor air quality when measuring temperature, relative humidity, CO2 or TVOC. The green LED is active as long as the measurement stays within the predetermined range. When the measurement exceeds that range, a visual alert is given via the yellow LED. In case the measurement reaches the pre-set alarm level, the red LED is activated. In case the sensor also has a buzzer, the red LED and buzzer are activated simultaneously. The sensors are available with 24 V or 230 V power supply. This simplifies the installation in existing buildings. The measured values are transmitted via the analogue output(s) and via Modbus RTU. All settings can be adjusted via Modbus RTU.
Sentera also offers intelligent sensors. Their smart algorithm controls one single output based on the measured values. This 0-10V output can directly control an EC fan, an AC fan speed controller or a damper actuator. A typical application is a class room with CO2 sensor. The CO2 sensor directly controls a supply and / or extraction fan. In case the green LED is active, the indoor air quality is good and the ventilation system is active at the minimum level. When the classroom is occupied, CO2 levels increase. Soon the yellow LED will light up and the ventilation rate will increase. The red LED lights up in case the CO2 concentration reaches the alarm level. The ventilation rate will be maximum. The alarm level can be reached in case too many people occupy the classroom or in case of clogged filters.
Monitoring and logging IAQ with Sentera Controls
After having installed the Sentera HVAC sensors in the rooms that you want to monitor, you can connect them via the Sentera PoM concept. PoM or Power over Modbus simplifies wiring, minimises installation costs and makes installations in existing buildings possible. It means that Modbus RTU communication and power supply are transferred via one cable with RJ45 connector.
A Sentera internet gateway helps to simplify the setup of your installation. All devices will automatically receive their own unique Modbus RTU address. Personalise your installation by adding the location of each device. That will make it easier afterwards to distinguish the kitchen sensor from the bedroom sensor.
Once your installation is set up, you can choose between local visualisation or remote monitoring. For local visualisation only, the internet gateway can be removed. In case you keep the internet gateway installed, all measured values and alerts are remotely available via SenteraWeb. Hard to choose? Why don’t you combine both: local and remote monitoring of your indoor climate!
SenteraWeb - Monitor your indoor air quality online
In case you keep the internet gateway installed, you have access to SenteraWeb, our online HVAC-portal. It enables you to monitor and adjust parameters via your computer or mobile device. Also data logging during a longer period is possible. The logged data can be displayed in graphs allowing trends to be discovered. For each installation, you can define different users and configurators. The users can monitor data while the configurators can adjust settings.
Each sensor in the installation can be given a specific name and location. You can select the most relevant parameters and visualise these on your personal dashboard. Each installation can have a different dashboard. Monitor your indoor air quality whenever you want, wherever you want.
HMI display to visualise indoor air quality
No internet connection available? In that case you can add an HMI with 5" colour display to your installation and monitor your indoor air quality locally.
The location of each sensor can be modified for ease of use. The 4 most relevant parameters for each sensor will be visualised on the home screen. In case one of the parameters is out of range, the pictogram will be highlighted. As is the case with all of our solutions, we put the focus on the simplicity of installation and use.