The design and operation of a centrifugal fan is very different from that of an axial fan. Because of their differences, each one suits different applications, and sometimes customers are unsure which fan type best suits their needs.
Axial fans date back to the horizontally arranged windmills of Europe in the Middle Ages. The first electric fans, introduced in the 1880s, were axial fans. Axial fans are named for the direction of airflow they produce. Blades rotating around an axis draw in air parallel to that axis and expel air in the same direction. Axial fans produce airflow at a high flow rate, which means that they have a large volume of air. However, the air currents they create are of low pressure. They require a low power consumption for their operation.
The centrifugal fan was invented in 1832 by the military engineer Lieutenant General Alexander Sablukov of the Imperial Russian Army of the Russian Empire. Centrifugal fans are often referred to as Blowers denoted and distinguished from axial fans. The pressure of an incoming airflow is increased by an impeller, a series of blades mounted on a circular hub. Centrifugal fans move air radially: the direction of outward airflow typically changes 90° from the inlet direction. The airflow created by centrifugal fans is directed through a system of ducts.??????? This helps create a higher pressure airflow than axial fans. Despite a lower flow rate, centrifugal fans produce a more even airflow than axial fans. Centrifugal fans also require higher power consumption.
Because of the high volume, low pressure airflows they produce, axial fans are best suited for general purpose applications. For example, they are great for moving air from one place to another, cooling small spaces like computers, and cooling larger spaces like work areas.
A standard AC model is energy efficient, consuming no more than 100 watts at high speed. AC fans can be connected directly to a DC power source such as solar panels or batteries. Since the end goal for devices like vending machines is a smooth flow of cooling power, an AC fan is a pretty obvious choice.
Due to the high pressure they generate, centrifugal fans are ideal for high pressure applications such as drying and air conditioning systems. Because all of their moving parts are enclosed, they also have particulate reduction properties, making them ideal for use in air pollution and filtration systems. Centrifugal fans also offer several advantages: