The germicidal action in air conditioning installations does a significant job in regards to the elimination of bacteria in the cooling coils.Much bibliography exists regarding the use of UVS system (ระบบ uvc, which is the term in Thai) to take advantage of their germicidal action in sterilization processes in HVAC systems.
There are different applications of Ultraviolet (UV) Light as a germicide in HVAC systems, ranging from improving the quality of indoor air in building environments, eliminating the bacterial load from the air in food industry processes, to controlling contamination airborne and virologic in health centers, among others.
The artificial generation of UV light is achieved by using a quartz lamp that contains mercury gas inside. When an electric current is generated between the lamp poles, ionization occurs causing the gas atoms to increase their energy substantially. Likewise, the heat produced increases the pressure of the gas and the higher excitation of electrons, causing them to jump and move in different wavelength lines, to the point of converting them into photons of light.
This photon energy, which is irradiated in the form of light, is what acts as a disinfectant, eliminating airborne microorganisms when the light wave crosses them as they penetrate the wall that protects the microorganism’s genetic information, thus damaging its structure.
It is worth clarifying that there are many types of microorganisms, bacteria and viruses that in turn have different resistance to these UV-C light radiations. For this reason, each one must be exposed to varying levels of radiation and exposure times to eliminate its structure.
In general, the application of these UV-C lamps is installed inside the Air Treatment Units (UTA) and in front of the cooling coils, as this is the place with the highest humidity where microorganisms proliferate easily.