Energy efficiency and performance considerations of variable frequency drives for air-cooled heat exchangers

The optimal operation of variable frequency drives (VFDs) are described for application on air-cooled heat exchangers (ACHEs) with multiple induction motors. The optimal excitation control of the motors is indicated for the desired airflow production. The effect of the variable airflow on the heat transfer performance of the ACHE is indicated. The effect and importance of different operating configurations of the motors are indicated.