Intelligent air filters monitor and analyse indoor air quality in real time

According to Ravi Kaushik, CEO and Founder, AIRTH, air curtains offer a cost-effective and efficient solution for preserving indoor air quality, curbing energy consumption, and elevating thermal comfort within buildings.

What is the purpose of an air curtain in the HVAC industry, and how does it contribute to energy savings and thermal comfort in a building?
The purpose of an air curtain is to achieve several key objectives. Its primary function is to prevent the exchange of indoor and outdoor air when doors or entrances are open. By expelling forceful airflow in a top-to-bottom manner, it creates a barrier between the indoor and outdoor environment. It functions as an unseen barrier, containing conditioned indoor air while barring external air, along with dust, insects, and pollutants, from infiltrating the indoor space.

Air curtains provide thermal comfort. They significantly contribute to maintaining consistent indoor temperatures by reducing air infiltration. They curtail the influx of external cold or hot air, thus stabilising the indoor environment and enhancing occupants’ thermal comfort.

An important purpose of air curtain is – it plays a pivotal part in enhancing HVAC system energy efficiency and improving indoor air quality. Through lessening air infiltration, the strain on heating and cooling equipment diminishes. This results in decreased reliance on the HVAC system to counter outdoor temperature fluctuations, leading to energy savings and reduced utility costs.

Air curtains also maintain superior indoor air quality by obstructing the entry of outdoor pollutants and contaminants. This is especially advantageous in urban areas with elevated pollution levels or locations near industrial zones.

In essence, air curtains offer a cost-effective and efficient solution for preserving indoor air quality, curbing energy consumption, and elevating thermal comfort within buildings. They find wide application in various settings, including commercial spaces, retail establishments, restaurants, warehouses, and manufacturing plants, where frequent door openings are common and energy conservation is imperative.

What effective air filter technologies are available?
The fundamental principle of air filtration remains unchanged. The particulate matter is captured between the filtering media as well as the gases are absorbed by the media. The microorganisms therein get deactivated by rupturing their outer membranes.

In the midst of technological progress, we are observing thrilling strides in air filtration, propelled by the possibilities of nanoscience – driven structural changes and innovative developments in filter media.
The field of nanotechnology has unlocked opportunities to rethink filtration frameworks, optimising surface areas and enhancing the capacity to capture particles. At the core of air filtration, the essence resides within the filter media. Continuous exploration and advancements have led to the emergence of increasingly effective and customised materials designed to address specific pollutants. Here are several emerging filters that are currently undergoing extensive research and development.

Antimicrobial air filtration systems: These filters are engineered to actively combat and eradicate bacteria, viruses, and other microorganisms present in the air. They utilise advanced materials or coatings with antimicrobial properties to minimise the risk of airborne infections.

Filters utilising graphene: Graphene, a thin layer of carbon atoms, possesses unique characteristics that render it an exceptional material for air filtration purposes. Filters incorporating graphene can adeptly capture ultrafine particles, thereby enhancing filtration efficiency.

Filters based on (MOF) Metal Organic Frameworks: MOFs, a category of highly porous materials, have the capacity to capture and store substantial amounts of gases and volatile organic compounds (VOCs). MOFs hold promising potential for eliminating harmful pollutants from the air.

Bio-air filters: These inventive filters harness living organisms, such as bacteria or algae, to metabolise and disintegrate airborne pollutants. Bio-air filters are environmentally friendly and provide a sustainable approach to air purification.

Electrospun filters: Electrospinning, a manufacturing process, produces nanofibers with significant surface area, enhancing their ability to trap ultrafine particles more effectively. Filters crafted using electrospinning technology exhibit superior capabilities in capturing particles.

Intelligent air filtration systems: Infused with Internet of Things (IoT) technology, intelligent air filters can continually monitor and analyse indoor air quality in real time. They can adjust their filtration levels based on identified pollutants, ensuring efficient and personalised air cleansing.

Eco-friendly filters: Addressing ecological concerns, eco-friendly air filters are engineered to naturally degrade over time, lessening their impact on waste generation and environmental pollution from landfills.

Electrochemical air filters: These filters employ redox reactions to eliminate specific airborne pollutants. Electrochemical air filters can target gases and volatile organic compounds, offering a customised approach to air purification.

Photo Electro Catalytic (PEC) air filters: By merging photocatalytic and electrochemical processes, PEC filters can proficiently degrade pollutants and transform them into harmless substances using light and electricity.

What are the different types of air filters commonly used in the HVAC industry, their applications and efficiency?
Each air filtration technology caters to distinct scenarios, depending upon particular requirements and prevailing environmental circumstances. The subsequent filters are the most prevalent ones utilised within the industry:

High-Efficiency Particulate Air (HEPA) Filters: These are unmatched in their ability to capture minute particles, allergens, and dust, providing purified air for both residential and workplace settings.

Activated Carbon Filters: These warriors combat odours, smoke, and harmful volatile organic compounds (VOCs), ensuring air that is both fresh and breathable.

Photocatalytic Oxidation (PCO): Harnessing the potential of UV light and catalysts to neutralise airborne pollutants, including bacteria and mold.

Ultraviolet Germicidal Irradiation (UVGI): Using UV rays to dismantle harmful microorganisms and viruses, maintaining the safety of indoor environments.

Electrostatic Precipitators: Harnessing potent static charges to capture larger particles, making them well-suited for industrial applications.

Plasma air purification: Generating ions to purify the air and reduce pollutants, creating an atmosphere that is refreshing and inviting.

Filters using nanotechnology: Incorporating state-of-the-art nanofibers and coatings to target ultrafine particles, offering the promise of cleaner air.

What are the recommended guidelines for the maintenance and replacement of air filters to ensure optimal performance and energy efficiency in an HVAC system?
We should strive to automate processes using real-time data; sensing and monitoring. The following recommendations outline these steps.

Implement real-time pressure drop measurement in air filters to monitor potential clogs. Also, monitor essential metrics such as air quality, humidity, CO2 levels, and other air quality indicators. Establishing an automated alert mechanism connected to real-time sensors is advisable. When sensors detect rising pressure drop or declining air quality, automated alerts can trigger immediate responses. Furthermore, incorporating real-time sensor data into building automation systems helps proper maintenance. This integration empowers HVAC systems to adapt to changing indoor air quality by adjusting ventilation rates and optimising filters functioning. These involve performance assessment, hence analyse HVAC system and air filter performance using data from real-time sensors. This analysis aids in spotting trends, addressing possible issues, and identifying areas for enhancement.

Consider outdoor air intake, surroundings and inspection: Recognise the possibility of outside air infiltration, especially considering outdoor conditions affecting indoor environments. Filter clogs could occur sooner during seasons like winter with higher air pollution challenges. Also, thoroughly inspect filter seals and gaskets to ensure a proper fit and prevent air leakage, which can compromise system efficiency and lead to energy wastage.

Other recommended guidelines include regular and monthly examinations of air filters to evaluate their condition, identifying visible dirt, dust accumulation, or damage, and also maintain detailed records of filter replacements and maintenance tasks. This record-keeping assists in monitoring system performance and adhering to a regular maintenance schedule.

Lastly, refer to the HVAC system manufacturer’s guidelines for specific advice on filter maintenance and replacement. Each system’s unique design and components may dictate distinct requirements.

What changes are taking place for implementing UVGI air purification technology?
UVGI has been established as a reliable technique to neutralise and deactivate airborne pathogens. These pathogens, encompassing bacteria, viruses, and mold, have their DNA or RNA disrupted through UVGI. The post-Covid era has witnessed heightened  awareness of UVGI, prompting esteemed organisations to establish comprehensive guidelines for its implementation. Listed below are significant changes and progressions in the incorporation of UVGI technology.

Advanced UV-C emitters: Progress in UV-C emitter technology has led to the creation of more efficient and long-lasting UV lamps and LEDs. These advanced emitters offer higher UV-C intensity while consuming less energy and enjoying extended lifespans, making them more suitable for HVAC applications.

Improved UV-C placement: Strategic placement of UV-C lamps within HVAC systems is crucial for effective air disinfection. Researchers and engineers are investigating the optimal positions for UV-C lamps to maximise their exposure to airborne pathogens without causing harm to system components or occupant health.

Automated UV-C control systems: Integrating automated UV-C control systems enables HVAC setups to adjust UV-C lamp operation based on real-time conditions. For instance, UVGI systems can be programmed to activate during HVAC operation when airflow is at the ideal level for optimal disinfection.

UV-C and air filter collaboration: Merging UVGI technology with air filtration systems can enhance air purification capabilities. Placing UV-C lamps downstream of air filters allows any pathogens that bypass the filters to be further neutralised by UV-C radiation.

Airflow and duct design considerations: Engineers are meticulously designing HVAC system airflow and ducts to ensure thorough UV-C irradiation throughout the air stream. Precise design and sizing are critical for achieving consistent disinfection outcomes.

Safety and monitoring features: Safety elements, like UV-C sensors that detect lamp operation and deactivate UV-C emitters in the presence of occupants, are becoming more prevalent to prevent inadvertent exposure.

UVGI for indoor air quality adherence: As indoor air quality gains prominence, UVGI technology is being applied to assist buildings in meeting ventilation and IAQ standards established by organisations such as ASHRAE.

How are the different types of air curtains effective for separating indoor and outdoor environments?
Various categories of air curtains effectively establish a division between indoor and outdoor areas through an air barrier at entrances.

Unheated air curtains propel ambient outdoor air across entrances, generating a temperature difference that forms a natural barrier against outdoor air infiltration. Although they do not heat indoor spaces, unheated air curtains offer a significant reduction in air infiltration, keeping the indoor environment more comfortable and energy-efficient.

Heated air curtains incorporate a heating component to warm the air circulated at entrances. This additional warmth enhances the barrier effect and counteracts cold outdoor air, especially during winter, preventing chilly drafts when doors are open.

Recessed air curtains are discreetly positioned within ceilings or floors, achieving concealed installations. Despite their inconspicuous presence, they still deliver effective barrier performance, making them ideal for applications where aesthetics matter.

Vertical air curtains emit air from top to bottom, creating a continuous vertical barrier across entrance widths. This design efficiently separates indoor and outdoor spaces, providing effective air sealing for wider doorways or taller openings.

Horizontal air curtains direct air along the floor, forming a barrier at ground level. This type suits spaces with low ceilings or scenarios where vertical air curtains aren’t feasible. Horizontal air curtains remain efficient separators, particularly when combined with other air curtain types.

High-velocity air curtains deploy robust fans to establish a potent, focused air barrier. This variation is effective in environments with strong air currents or challenging weather conditions.

Low-velocity air curtains produce a gentle, streamlined airflow, suited for scenarios requiring a subtler air barrier. They are often used in places where a comfortable environment is a priority, such as restaurants or retail establishments.