Table 1.

Structure, advantages, limitations, and range of application for rotors

Category	Structure	Advantages	Limitations	Applications
Horizontal rotor	•Lifting airfoil blade •Rotation axis parallel to wind direction •With yaw mechanism	•High wind energy utilization •High starting torque, easy to start •Low torque pulsation, high reliability	•Wind direction dependency •Low space utilization •Complex blade design and manufacturing with high production costs	•Low-mid-high wind speed ambient •High power demands •High-reliability requirements
Darrieus rotor	•Lifting airfoil blade •The rotor axis perpendicular to wind direction •Yaw mechanism absence	•High wind energy utilization •Omni-directional design: no requirement to face the wind •Compact rotor structure: high space utilization	•Low starting torque and difficulty with self-start •High torque pulsation and parts fatigue •High operating speed, reliability reduced	•Mid-high wind speed ambient •Space size limitation •Mid-high power demands
Savonius rotor	•Non-lifting airfoil blade •The rotor axis perpendicular to the wind direction •Yaw mechanism absence	•High starting torque, easy to start •Omni-directional, requiring no facing into the wind •Simple structure, low production cost	•Low wind energy utilization •Slow rotor speed, low power generation potential	•Low wind speed ambient •Low noise level •High-reliability requirements