The focus of this article is the application of UV- light energy to inactivate microorganisms, specifically bacteria, fungi and viruses on surfaces and in air streams in the HVAC system. The Ashrae Standard for UV-lights 185.1 and 185.2 discuss methods of testing for UV- lights for use in air-handling units and air ducts to deactivate airborne microorganisms.
Conditions in the air-handler can promote the growth of bacteria and mold-containing biofilms on damp or wet surfaces such as cooling coils, drain pans, plenum walls, fans and filters.
Cooling coil fouling by biofilms can increase coil pressure drop and reduce airflow across the coil reducing efficiency of the equipment. As well, UV-lights have been shown to be effective in reducing airside pressure drop and increasing air-side heat transfer of cooling coils.
Proper placement of UV-lights in air-handler equipment is very important as to have the maximum irradiance on components of the air-handler especially the cooling coil. Locations of components in the downstream of the cooling coil are particularly susceptible because of condensation and carryover moisture from the coil.
Field studies in the United States in hot, humid climates report significant improvements in air-side pressure drop and heat transfer in the cooling coil. A system in Tampa, FL, experienced a 22% reduction in pressure drop and 15% increase in air-side heat transfer in the cooling coil after less than 2 months of surface treatment. The addition of UV-lights along with proper filters and regular maintenance will insure proper operating conditions for your HVAC system and indoor air quality.
To learn more information about UV lights, call our A/C hotline at 321-288-5757 or check out this article by our UV light suppliers: https://www.freshaireuv.com/residential/blue-tube-uv/