Fan Law 1 establishes a critical relationship between the Cubic Feet per Minute (CFM) of air moved by a fan and its Revolutions Per Minute (RPM). This law states that CFM is directly proportional to the fan’s RPM, meaning that any change in RPM results in an equivalent change in airflow. This understanding is fundamental for HVAC professionals looking to control and optimize the air movement within different systems.
Fan Law 1: Relationship Between CFM and RPM
Law: CFM is directly proportional to the fan's RPM.
Formula: CFM2 = CFM1 × (RPM2 ÷ RPM1)
Practical Meaning: Increasing or decreasing the fan's RPM will proportionally increase or decrease the airflow (CFM). A 10% change in RPM results in a 10% change in CFM.
Field Application: To adjust airflow, technicians can change the fan's speed. For example, decreasing a fan's RPM from 1100 to 990 will decrease airflow from 1000 CFM to 900 CFM.
Understanding and applying Fan Law 1 is essential for precise control over HVAC systems. By adjusting the RPM, technicians can directly influence airflow to meet specific requirements, ensuring systems operate efficiently and effectively. This law is a foundational principle when addressing changes needed for system performance and comfort levels in various settings.
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