constant air volume flow rate, torque, speed, altitude
Accurate constant air volume flow rate regulation is essential in HVAC&R systems to provide comfort and required system performance. In the motor, the torque is regulated to provide the required air volume flow rate by monitoring the motor rotational speed. Various correlations including exponential functions and high order of polynomials used to regulate the torque in terms of motor speed and air volume flow rate are presented in the literature. However, all these formulas have not addressed the issue of inaccuracy of the air volume flow control in high altitudes regions. Therefore, a new 5-coefficient formula is proposed in this paper to maintain the constant air volume flow rate even when the altitude changes significantly.