The Prevention of the Snow Entrance to the HVACsystems

Entrance of snow into the HVACsystemsis common problem in the arcticandsubarcticclimates and may cause moistening or wetting of filters and outdoor air chambers whichpromotes microbe growth. Blocking the filters also increases pressure drop or even damages thefilters. The design features and velocity of air in the outdoor air intake play key role when theproblems occurs. To eliminate the snow entrance into the HVACsystemsthe face velocity of theoutdoor air shall be below 1 m/s at the intake louvre. The pressure caused by wind is one of theexternal conditions that influence the snow penetration through the intake louvre and somesolutions for elimination of this problem are presented. If the snow, however, is entranced to theHVACsystemgood design and hygiene control of the intake section of the HVACsystemisimportant which is discussed more detailed in this paper.