One of the biggest mistakes you can make after implementing an air quality monitoring system is underutilizing your data. Beyond just using air quality data for spot checks, you can employ your air quality data in your building automation system to promote efficiency and good indoor air quality.
What Is Building Automation?
Building automation systems (BAS) are sets of interconnected sensors and actuators designed to control, monitor, and regulate buildings and building equipment. Building automation systems can manage all of the systems below and more:
- Emergency response
- Humidity control
When implemented correctly, these systems can reduce energy consumption, lower maintenance costs, extend the lifecycle of utilities, and ensure the safety and comfort of building occupants. In fact, in one study by PNNL, commercial buildings that correctly employed BAS reduced energy consumption by an average of 29% without sacrificing indoor environmental quality.
IAQ Sensors and BAS
As we mentioned above, sensors make up a crucial component of any building automation system. Sensors collect the data inputs used to control output devices like ventilation systems, and indoor air quality sensors are some of the primary sensors used in these building automation networks.
Occupancy, carbon dioxide (CO2) sensors, and DCV
One established application of indoor air quality sensors is through demand-controlled ventilation (DCV).
Demand-controlled ventilation is a feedback system designed to optimize ventilation rates based on occupancy. Indoor air pollution can be broken down into two types: air pollution originating from humans and air pollution for off-gassing unrelated to occupancy. During low-occupancy periods, there are fewer sources of indoor air pollution, so ventilation rates do not need to be as high to maintain the same air quality.
Occupancy can be measured in four ways:
- Carbon dioxide sensing - CO2 sensors are the most common way of regulating DCV systems. Carbon dioxide levels directly correlate with occupancy, so some DCV systems will adjust ventilation rates in response to changes in CO2 concentrations.
- Occupancy counting - Occupancy can be measured or estimated through counts using ticket sales, turnstiles, or security swipes, and as is the case with CO2 sensors, ventilation rates will vary based on occupancy counts.
- Occupancy sensing - Lighting or occupancy sensors can likewise estimate occupancy. DCV systems with occupancy sensing typically only have two modes; ventilation rates will be the same whether there is one person or twenty people in a space.
- Scheduling - Occupancy can be estimated based on scheduled use. For example, ventilation rates for a meeting room can be maximized when the meeting room is booked and reduced when nothing is planned in it.
As the leading way to estimate occupancy, CO2 sensors play an essential role in demand-controlled ventilation systems. Additional inputs from TVOC sensors can also help measure occupancy and ensure IAQ remains good during occupancy periods, as volatile organic compounds (VOCs) are a major indoor air pollutant. However, due to many factors unrelated to occupancy that create VOCs, carbon dioxide is usually a better input for DCV.
Particulate matter sensing and HVAC systems
Unlike carbon dioxide, particulate matter is a concern for both indoors and outdoors, and high levels of outdoor particulate matter can adversely impact indoor environmental quality, or IEQ.
In cases where a building is located in an area with high levels of air pollution, or during pollution events or wildfires, outdoor and indoor particulate matter sensors can help automate air filtration and ventilation to optimize indoor air quality. For example, when levels of outdoor particulate matter are higher than indoor levels, then a higher percentage of air should be recirculated to minimize the intrusion of air pollution. Likewise, if indoor levels are higher, the reverse should occur.
Measuring particulate matter can also help you manage your air filtration system. Increasing the efficiency of your air filters will help clear out more particles but can also increase energy costs and restrict airflow. Indoor particulate matter readings will help you know if your current air filters are suitable, and high indoor particulate matter readings could be used as an alert to check that your air filtration system is in good working order.
Thus, utilizing particulate matter sensors alongside CO2 sensors can help you minimize energy costs through DCV while simultaneously ensuring that indoor air pollution is under control.
Ozone sensing and secondary air pollutants
Another air pollutant to use as an input in building automation is ozone.
Most indoor ozone comes from the outdoors, either by seeping in through doors and windows or the ventilation of outdoor air. While the ozone levels typically found indoors may not be dangerous to building occupants, ozone can contribute to the formation of secondary air pollutants. For example, the O3 oxidation of monoterpenes (found in essential oils) can create particulate matter, and the O3 oxidation of skin oils can produce VOCs.
While increasing ventilation will dilute VOCs and carbon dioxide, ozone readings may increase with the increase of outdoor air. Incorporating ozone sensing into your building automation system will, much like particulate matter, ensure that the ventilation controlled by a DCV system maintains healthy indoor air quality.
Thermal comfort and climate controls
The final parameters we will discuss aren’t strictly indoor air quality parameters, but they do closely connect to building comfort and automation. Some air quality monitors that measure particulate matter and carbon dioxide will also measure temperature and relative humidity, so you get extra bang for your buck.
Temperature and humidity both contribute to the overall thermal comfort of a space, and data from temperature and humidity sensors can be integrated into building automation systems to regulate indoor climate controls. Incorporating temperature and relative humidity readings can also help you preempt seasonal weather changes. This data is critical during the COVID-19 pandemic, as both factors have been shown to impact viral transmission rates.
Indoor air quality monitoring can have an array of applications in building automation systems. To learn more about how to find the perfect commercial air quality monitoring system, check out our detailed course below!