HVAC systems are dealing with more demands than ever before. Energy use needs to come down, indoor air quality needs to be high and pathogens need to stay out. Add in reasonable purchase and maintenance costs and the challenge seems insurmountable. Luckily, with rising demands has come improving technology. For example, we wrote recently about the benefits of HVAC coatings, namely how they lower costs, improve indoor air quality and improve energy efficiency. We mentioned that some coatings can help prevent the spread of viruses and bacteria. In this article, we’ll focus on one such HVAC coating: zeolite with silver nanoparticles. The coating has many useful properties, including preventing the spread of viruses such as COVID-19.
We recently published an article about how HVAC systems can help in the fight against COVID-19. HVAC Insider also wrote a nice article about the known characteristics of how the virus interacts with HVAC systems. While helping to deal with the current pandemic is a worthy goal, we should also note that this zeolite coating is capable of much more. Before we get to the benefits though, let’s start with some basics.
What is zeolite?
Simply put, zeolite is a kind of rock. The word zeolite literally means boiling stone. When heated, naturally occurring zeolite can steam like a boiling pot of water. From that natural curiosity, it eventually became a useful group of materials that now has over 100 synthetic variants. Zeolite is generally characterized by its stable form and resistance to all sorts of harsh conditions: extreme temperatures, high pressure and corrosive elements, for example. Synthetic forms of zeolite make for good metal and ceramic coatings. They have all sorts of useful applications such as preventing corrosion in automotive and medical components. The molecular structure of zeolite has a property which turns out to be useful for coatings. It has a regular pore structure. The pores, which stored water and gave zeolite its name, can be used to incorporate molecules that introduce other interesting properties.
Silver nanoparticles are one possible addition.
SEM image (scanning electron microscope), zoom 25.000
What are silver nanoparticles?
Silver nanoparticles (also known as AgNPs and nano AG) are between 1 nm and 100 nm in size and contain silver (Ag) atoms, as the name would suggest. The silver is often combined with other elements to create different shapes and produce the desired properties for any given use case. Silver nanoparticles have an abundance of applications, from medical to industrial. What interests us most in the context of HVAC systems are their antimicrobial properties. In short, the presence of silver nanoparticles makes life much harder for viruses, bacteria and fungi.
The benefits of a zeolite coating with silver nanoparticles
By combining zeolite and silver nanoparticles, we get a highly stable and resistant coating with antimicrobial properties. You can probably already imagine some benefits that could have in an HVAC system.
Health and indoor air quality
1. Prevent buildup of viruses, bacteria and fungi
Pathogens won’t be able to live for long periods on the coating and even those that just come into contact with a coated rotor could be killed. This makes it much harder for pathogens of any kind to survive in, or spread through, the ventilation system.
2. Reduce cross-contamination between airflows
Since pathogens can’t build up on rotors with the zeolite coating, there is a much lower risk of any cross-contamination between airflows. This is important in applications where one airflow has a much higher risk of carrying pathogens.
3. Reduce ventilation system odours
Many ventilation system odours are caused by the buildup of fungi. The zeolite coating can help prevent the buildup and internal spread of fungus spores.
4. Enable technology to actively disinfect the airstream
Having a zeolite coating on rotors and other components is mostly a passive method. Some pathogens in the airstream may be killed but the coating is most effective at preventing the buildup of pathogens. However, titanium oxide (TiO2) can be added to the zeolite coating with silver nanoparticles to create an active barrier using UV light. This also minimizes the transfer of volatile organic compounds in the airstream.
Better performance and lower maintenance costs
5. Prevent buildup of biofilms to improve performance
Eliminating the buildup of bacteria is also good for preventing the formation of biofilms on rotors. Biofilms are colonies of bacteria that introduce aerodynamic drag in HVAC systems, hurting performance.
6. Improve the hygiene of the entire air holding unit
By preventing buildup of pathogens on rotors, the hygiene of the whole air holding unit will be better.
7. Improve the hygiene of parts near rotors
Applied to components around rotors, the zeolite coating can improve system hygiene even further.
8. Reduce cleaning costs
Improved hygiene also means lower cleaning costs. You won’t have to clean the system as often and the cleaning methods can be simpler.
Swiss Rotors zeolite coating
Swiss Rotors is incorporating zeolite coatings with silver nanoparticles into its product line. We don’t have all the technical specifications ready for release yet, but we’ll announce more soon. What we can say now is that we’ll be producing coatings that act as passive barriers as well as active barriers activated by UV light. We’re also preparing certification with health authorities to assure that each product meets the hygiene standards listed above. This is just one of the technologies that Swiss Rotors uses to help customers improve indoor air quality, reduce energy consumption and lower costs. If you want to hear more about our full product line, be sure to get in touch.