Centrifugal fan is not a positive displacement equipment. Compared with positive displacement fan, centrifugal fan has certain advantages and disadvantages: centrifugal fan has higher efficiency, while positive displacement fan has lower capital cost and can achieve higher compression ratio.      in residential, industrial and commercial applications, centrifugal fans are usually compared with axial fans. Axial flow fans usually operate at high volume, low static pressure and high efficiency.  Therefore, axial fans are usually used for high-capacity air flow, such as warehouse exhaust or room circulation, while centrifugal fans are used to move air in pipeline applications, such as houses or typical office environments.