An emerging bit of innovation in the sphere of lighting and air quality control has been the creation of LEDs that emit ultraviolet (UV) rays. For a while UV-C lighting has been hard at work disinfecting rooms in the healthcare setting, but it’s only been recently that LEDs have approached being able to generate this type of light. This also comes at a time when public interest in germicidal lighting is at an all time high.
However, between potential technological limitations of these UV LEDs and public interest in the solution in general, its uncertain as to where the market may go with this.
What is UV-C?
An important thing to know is just how UV-C lighting gets used in current applications. As mentioned, it’s a popular tool for disinfecting hospital rooms because UV-C inactivates viral particles. Additionally, UV-C gets used in commercial HVAC ducts for air and water pan disinfection. It also gets incorporated into ceiling fixtures to disinfect air close to the ceilings.
It’s even more important to know the difference between “UV-C” lighting, also known as “far-UV,” and visible-light radiation. Both are on the UV spectrum, but while UV-C sits at around 222 nm and can only be used in specific applications due to its intensity, visible-light radiation sits at 405 nm and is more often touted for its use in continual disinfection due to its safety profile for occupants in a space.
For continual disinfection, its best to view it as a means of halting the growth of bacteria and fungi in places that they may commonly develop. Meanwhile UV-C, is far more intense and can be harmful to human skin and eyes with prolonged exposure. But that’s what makes it exceptionally useful for inactivating harmful pathogens.
The Issue with UV LEDs
As of right now, most UV LEDs available now sit at around 275 nm for wavelengths.
According to LED Magazine, CEO Mike Krames of Arkesso, LLC, recently delved into the topic of manufacturing for these products, claiming that, similar to visible light LEDs, UV LEDs can be expected to experience a big performance ramp, eventually leading to more efficient and cost-effective UV LEDs to enter into the market.
Bob Karlicek, director of the Center for Lighting Enabled Systems & Applications (LESA), meanwhile has a different outlook on the technology’s potential. “LEDs will just gradually start off at increasingly shorter and shorter wavelengths, but as their wavelengths come down from typically where UV-C LEDs are available right now at 275 nm, they get lower and lower in terms of power output, and of course less economically viable.”
Take for instance, the case of HVAC disinfection now. While UV-C is effective at disinfecting these units, it doesn’t get used nearly as much for it as it does with upper air systems or hospital applications. And when it does get used, it’s mercury lamps instead of LEDs.
Karlicek states it as thus, “LED lifetimes are still short relative to mercury lamps; mercury lamps have the highest efficiency of producing UV-C radiation — they can be up to 30% efficient.” He continued, “Right now, LEDs really aren’t being used in HVAC systems. They’re too expensive, too small, they don’t have enough output power, and they’re not reliable enough.”
Where’s the Market Then?
Ultimately, the focus of this surge in interest falls upon upper air systems (such as ceiling fans or other light fixtures) being able to disinfect pathogens (namely the SARS-CoV-2 and influenza pathogens) in commercial and even residential settings due to heightened air quality concerns. But, Karlicek had other avenues UV LEDs could potentially branch off into.
“I think UV LEDs could be very interesting for controlled environment agriculture, in the suppression of mold growth in places where crops are increasingly being grown indoors. There may be environments where you need to suppress various virus and fungal things that attack crops, and these technologies would be valuable there,” Karlicek observed.
He also referenced systems used in detecting bacteria and pathogens, as well, but then asked a question that all people looking to respond due to this surge of interest should be mindful of: How likely are people to forget about COVID and go back to worrying less about