By Kevin Stockton
From the June 2023 Issue
From sick building syndrome to the COVID-19 pandemic to overall workplace wellness, concerns around indoor air quality (IAQ) have evolved. The good news is that heating, ventilation, and air conditioning (HVAC) technology has evolved, too. Whether a building needs a new HVAC system or a retrofit for a legacy system, these changes can help building managers ensure occupant health and safety, without sacrificing operational efficiency.
Since the late 1970s, IAQ has been increasingly recognized as having a direct effect on the health and well-being of building occupants. Recently, the impact of HVAC systems in the fight against airborne virus transmission has generated a renewed focus on air quality. In fact, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Standard 62.1 provides ventilation guidelines to help make sure proper indoor air quality levels are maintained.
Health and wellness have become a focal point in the workplace, even as new challenges emerge. In fact, 96% of employees agree that a healthy work environment is necessary for productivity, and research suggests IAQ can play a role in creating a healthier work environment. However, the introduction of fresh air, improved filtration, humidity control, and other air treatment methods can raise concerns about the potential for higher system loads—and the increased energy use that can result. The issues around energy use are increasingly important, as many organizations now have sustainability and carbon reduction goals, making emissions reductions and energy savings a priority.
Improved ventilation is often a fundamental way to improve IAQ, but ventilation alone can result in loss of efficiency as untreated warm or cool air is introduced into the system. Fortunately, there are solutions. Energy recovery wheels (ERWs), or counter-flow heat exchangers, can increase the amount of fresh air brought into a building while minimizing energy loss. This cost-effective method transfers energy between an exhaust (indoor) airstream and an incoming fresh airstream to precondition the incoming air, making it closer to the desired indoor temperature and humidity conditions.
The introduction of fresh air provides immediate benefits—but it’s energy-intensive. Therefore, increasing ventilation alone won’t solve every air quality challenge. The EPA estimates the concentrations of some pollutants are 2-5 times higher in outdoor air than indoor air, which means dust, dirt, pollen, and other irritants can cause or otherwise exacerbate existing respiratory issues, allergies, asthma, headaches, and other illnesses.
Innovative Strategies To Improve IAQ
Proper application of modern HVAC technologies can go a long way toward improving IAQ.
Fortunately, proper application of modern HVAC technologies can go a long way toward improving IAQ. These technologies can clean indoor air and maintain ideal humidity levels to help reduce irritations and improve occupant well-being while minimizing losses in operational efficiencies.
Germicidal UV-C Lights: This fast-evolving technology uses ultraviolet germicidal irradiation (UVGI) to kill or inactivate mold, mildew, dander, bacteria, and viruses. By using UV-C light (short-wave; 280 to 200 nm) to damage the nucleic acids and proteins of pathogens, it provides disinfection qualities. These devices can be mounted in ductwork or air-handling units (AHUs) so they stay cleaner longer and run more efficiently. In high-condensation areas of system components, like indoor coils, UV-C lights also help combat mold and bacteria. These germicidal lights are easy to retrofit and have become a popular option for engineers and building owners to help them meet ASHRAE requirements, particularly in high-density locations.
Pre-Filters and Final Filters: In a multi-filter system, a pre-filter catches large contaminants to help improve IAQ and protect the more expensive final filter. Pre-filters and final filters can be made of a variety of materials, including:
- Electrostatic Filters: With microscopic cotton and paper fibers that generate a charge when in use, these filters attract more contaminants than less-expensive options.
- Fiberglass Filters: Spun fiberglass filters are among the most common filters found in AC and furnace units and are primarily used to catch large airborne contaminants. Fiberglass filters are an easy-to-find, cost-effective solution, though they lack some capabilities found in other filter types.
- HEPA Filters: Often used in healthcare settings to reduce the spread of infection, high-efficiency particulate air (HEPA) filters tested to be at least 99.97% effective at removing particulates as small as 0.3 microns.
- Pleated Filters: Pleated filters—among the more reasonably priced options—are more tightly woven than fiberglass, making them a better choice for catching contaminants like dust mites.
Humidification/Dehumidification: It is well understood that higher indoor humidity levels can make a room feel too hot, while lower levels can make a room feel too cold. However, comfort levels are only part of the humidity story. An imbalance in humidity levels can also allow mold, bacteria, and viruses to grow. In fact, research is indicating proper humidity control may play a role in combating the COVID-19 virus. In its April 2020 report, the ASHRAE Epidemic Task Force indicated that “maintaining indoor relative humidity >40% will significantly reduce the infectivity of aerosolized virus” and midrange humidity levels may likewise be associated with improved respiratory immunity. Modern humidification control systems can help maintain optimal humidity for improved IAQ.
Smart Technology: The Internet of Things (IoT) can do more than help buildings and systems stay connected and run more efficiently—smart technology can also improve health and comfort. For example, technology can schedule changes and send notifications when a room is over- or undercooled. Smart controls like fault detection and diagnostics (FDD) use multiple sensors to continuously monitor economizer operation, as well as outdoor factors, like humidity and temperature. FDD algorithms then process the data and deliver detailed alerts when needed to help ensure equipment is performing as specified.
Proactive monitoring allows building managers to respond to issues before they first arise, taking a proactive approach to HVAC management and maximizing the life cycle of an HVAC system.
Making The Most Of Modern HVAC Technology
Better indoor air quality directly impacts the health and comfort of its occupants—and it doesn’t have to come at the cost of energy efficiency. Newer disinfecting and virus-deactivating technologies should be considered as part of a holistic approach to occupant health and well-being. By identifying the best solution for each unique application, modern HVAC technologies can balance the needs of occupants, operators, and owners to improve building air quality while maintaining a high degree of operational efficiency.
Stockton is Director of Large RTU Product Management at Johnson Controls. He has a bachelor’s in industrial engineering from Ohio State University.
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