What Ultraviolet light

Ultraviolet (UV) light is one form of electromagnetic energy produced naturally by the sun. UV is a spectrum of light just below the visible light and it is split into four distinct spectral areas – Vacuum UV or UVV (100 to 200 nm), UVC (200 to 280 nm), UVB (280 to 315 nm) and UVA (315 to 400 nm). For more details, see our complete post here

What is Ultraviolet C?

The entire UV spectrum can kill or inactivate many microorganism species, preventing them from replicating. UVC energy at 253.7 nanometers provides the most germicidal effect. The application of UVC energy to inactivate microorganisms is also known as Germicidal Irradiation or UVGI.

UVC exposure inactivates microbial organisms such as bacteria and viruses by altering the structure and the molecular bonds of their DNA (Deoxyribonucleic acid). DNA is a “blue print” these organisms use to develop, function and reproduce. By destroying the organism’s ability to reproduce, it becomes harmless since it cannot colonize. After UVC exposure, the organism dies off leaving no offspring, and the population of the microorganism diminishes rapidly.

Ultraviolet germicidal lamps provide a much more powerful and concentrated effect of ultraviolet energy than can be found naturally. Germicidal UV provides a highly effective method of destroying.

It’s not just dirt – it’s biological. What is HVAC biofilm?

Some people call it dirt. Some call it mud, slime or sludge. This gluey matrix growing on heating, ventilating and air conditioning (HVAC) evaporator coils, drain pans and ducts is, in fact, biofilm. Biofilm is an active, complex microbial matrix of mold and bacteria that adheres to the fins of the coil and protects the organisms from biocides.

The biofilms themselves give off prod­ucts of metabolism known as volatile organic compounds (VOCs) which may range in effects from watery eyes and head­aches, to more severe allergy and asthma responses.

Numerous studies have demonstrated that the HVAC system is a viable amplifier, reservoir and disseminator of pathogenic and opportunistic bacteria, viruses and mold. The list below identifies some of the many microorganisms that have been isolated from evaporator coils, drain pans, ducts, final filters and diffusers.

No matter how good the coil cleaner, sprayer or pressure washer used, the effectiveness of these methods reaches about 1 inch into the coil and the organic and biologically active matter gets packed deeper into the coil fins.

Installed on air effluent side of the condensate cooling coils and the drain pan, UVC energy destroys surface biofilm and airborne microorganisms before they circulate throughout the HVAC system.

Numerous studies have demonstrated that the HVAC system is a viable reservoir of pathogenic and opportunistic bacteria and mold. Below is a partial list of microorganisms that have been found on evaporator coils, drain pans and ducts:

How does HVAC biofilm impact indoor air quality?

The quality of indoor air, influenced by the levels of bioaerosols, contaminants and pollutants, can affect occupant health and development, resulting in reduced productivity and increased absenteeism. The biofilms themselves give off products of metabolism known as volatile organic compounds (VOCs) which can trigger occupant complaints of watery eyes and headaches and even severe allergy and asthma responses. The biological contaminants typically found on HVAC coils and drain pans have also been linked to Sick Building Syndrome (SBS) and hospital acquired infections.

How does HVAC biofilm impact HVAC energy use?

Biological fouling of evaporator fin and tube heat exchangers is a key contributor to decreased HVAC capacity. The biological fouling acts as an insulator, increasing air flow resistance and decreasing heat transfer. The fans run longer to maintain the building at the desired temperature, increasing kW draw with reduced cooling tonnage capacity. A mere 10% increase in fan motor run can significantly increase energy use. The chillers and pumps work harder to raise the leaving water temperature and achieve set temperature points. For each degree the water temperature is increased, a savings of 1-2% will be realized.

High output UVC provides continuous cleaning of coils, eliminating the biofilm that causes reductions in operational efficiency. Studies have shown that removal of a .024” layer of biofilm can reduce HVAC energy usage by 21% by restoring heat transfer and system efficiency. Reduced cooling coil pressure drop helps save fan energy, while improved cooling coil heat transfer efficiency. Higher chilled water temperature setpoints allows the chiller plant to operate more efficiently.