Ilmanvaihtokäyrä

Ilmanvaihtokäyrä, sometimes translated as ventilation curve or air exchange curve, is a graphical representation used in building design and ventilation engineering. It illustrates the relationship between the airflow rate and the pressure difference across a ventilation system or component, such as a duct, fan, or diffuser.

The curve is typically plotted with the airflow rate (often in cubic meters per hour or liters per second) on the vertical axis and the pressure difference (measured in Pascals or millimeters of water column) on the horizontal axis. The shape of the curve is determined by the resistance to airflow encountered by the system. Higher resistance leads to a steeper curve, meaning that a greater pressure difference is required to achieve a given airflow rate.

Ilmanvaihtokäyrä is a crucial tool for selecting appropriate ventilation equipment, such as fans. By comparing the system's resistance curve with the performance curves of various fans, designers can identify a fan that can deliver the required airflow at an efficient operating point, minimizing energy consumption and noise. It also helps in system balancing, ensuring that air is distributed evenly throughout a building according to design specifications. Understanding and utilizing ilmanvaihtokäyrä is fundamental for achieving effective and energy-efficient indoor air quality.