Which fan control method reduces power usage at lower loads?

Inlet Damper Control is effective in reducing power usage at lower loads by adjusting the amount of air entering a fan system. By partially closing the dampers when the demand for airflow decreases, the system can maintain proper operation without using excess energy. This approach allows the fan to operate more efficiently under varying load conditions, as it prevents the system from producing unnecessary airflow that would lead to wasted power.

Moreover, Inlet Damper Control specifically adjusts the airflow rather than the fan speed or frequency, making it a straightforward method to manage energy consumption. This method is particularly beneficial in applications where variable airflow requirements are common, as it aligns the system's output more closely with actual demand.

In contrast, other control methods might not provide the same level of efficiency at lower loads. For example, a Variable Frequency Drive adjusts the speed of the motor to match the required air volume, which can also be energy-efficient but may not be as straightforward as simply adjusting the damper position. Constant Air Volume Control maintains a fixed airflow regardless of load, which does not reduce power usage effectively at lower loads. Speed Control can adjust output but often does not optimize energy use as well as Inlet Damper Control under certain conditions.