Molecular Filtration in HVAC Systems

The recent episode of the Talking Air Filtration Podcast delves into the critical role of molecular (gas phase) filtration in HVAC systems. Sean Gilstorf and Dave Schaaf explore the necessity of molecular filtration to eliminate extremely small contaminants that even the most advanced particulate filters cannot remove. They discuss various filtration mediums, such as activated carbon from diverse sources (like coconut shells and coal), and their efficiency. Key concepts such as adsorption and chemisorption are explained, alongside practical advice on choosing the appropriate filters based on factors like carbon load and pressure drop. The episode touches on different applications, from hospital settings to combating odors, and highlights the importance of identifying specific contaminants and their concentrations for effective filtration. View the speaker’s slides here: https://amped.egnyte.com/dl/RGQ5WZm7Ew View detailed show notes and use timestamps to navigate the episode: [0:48] Introduction to the podcast and guests Sean Gilstorf and Dave Schaaf, who will discuss molecular filtration in HVAC systems. [1:35] The necessity of molecular filtration for removing ultra-fine contaminants, with a detailed explanation of terms like charcoal, gas phase, and molecular filtration. [2:45] Comparing particulate matter and gas phase contaminants – why HEPA or OPA filters are insufficient for molecular filtration. [3:30] Overview of molecular contaminants categorized as corrosive, toxic, or odorous, with examples like hydrogen sulfide and chlorine. [5:16] Definitions of physical adsorption and chemisorption with examples, emphasizing the surface area and capacity required for effective molecular filtration. [7:11] Review of different substrates used in molecular filtration (activated alumina, zeolites, activated carbon), and their sources such as coconut shells, coal, and wood. [8:30] Addressing typical applications and the role of impregnated carbon in removing various contaminants. [11:03] Sean Gilstorf discusses different products used in the HVAC market, including pleated and mini-pleat filters, and their loading capacities. [11:48] The relationship between filter performance, carbon load, pressure drop, and breakthrough efficiency. [23:17] Various filters for different applications, their usability, and how to choose based on contaminant concentrations. [28:34] Key advice on pre-filter media layers and retrofitting filters for extended carbon filter life. [33:02] The speakers begin the Q&A segment of the presentation [33:21] Examples of case studies and insights into wildfire smoke filtration solutions for better indoor air quality. [36:10] Further questions in the Q&A segment address filtration challenges, molecular filtration’s role in virus containment, and practical advice for field applications. For more resources and information: https://www.nafahq.org/molecular-filtration