Luftväxlingseffektivitet

Luftväxlingseffektivitet, often translated as air change effectiveness, is a measure used in ventilation engineering to quantify how well fresh air is distributed throughout a room or building. It goes beyond simply measuring the total volume of air supplied and exhausted per hour (air change rate). Instead, it assesses the ability of the ventilation system to deliver clean, fresh air to occupied zones and remove pollutants from these same zones.

High luftväxlingseffektivitet means that the supplied fresh air effectively displaces the stale air in the occupied areas, leading to better indoor air quality. Conversely, low effectiveness indicates that fresh air may be short-circuiting, meaning it exits the room before reaching occupants, or that stagnant zones with poor air quality exist. This can occur due to factors such as poor diffuser placement, inadequate air velocity, or internal heat loads creating air currents that interfere with intended airflow patterns.

Measuring luftväxlingseffektivitet typically involves tracer gas experiments. A non-toxic tracer gas is introduced into the room, and its concentration is monitored over time in different locations. By analyzing the decay or distribution of the tracer gas, engineers can determine how effectively the ventilation system is flushing out contaminants and delivering fresh air to where it's needed most. This metric is crucial for designing efficient and healthy indoor environments, particularly in spaces where air quality is paramount.