Factors That Determine Ceiling Fan Airflow

There are several parameters or, if you prefer, characteristics that affect the efficiency of a ceiling fan. Among them, ceiling fan capacity is the most important factor. The rest of the characteristics are of indirect importance, but nevertheless, without them, it is impossible to form a picture of the efficiency of the fan chandelier.

• Ceiling fan capacity - is the volume of air mixed by the ceiling fan per hour. Measurement unit: [m³ / h].
• Ceiling Fan Speed - The speed at which the ceiling fan motor rotates [rpm]. Directly affects performance: the higher the rotation speed, the higher the performance.
  
• Ceiling Fan Blade Width - affects the performance of the ceiling fan. With equal diameters of dopas and the same speed of rotation of two ceiling units, the performance will be higher for the one with the wider blades. There are times when the fan performance is too high. In such cases, the fan speed is reduced.
  
• Blade Span Diameter or Blade Length - The longer the length of the ceiling fan blades, the larger the area of the room will be affected by the ceiling fan. Most ceiling fans come in 90mm, 120mm, 140mm, 160mm blades.
• The angle of inclination of the blade relative to the horizontal axis of this blade - affects the performance of the ceiling fan: the greater the tilt angle, the higher the performance. The greater the angle of inclination, the greater the loads the fan motor experiences. The maximum load on the engine occurs at maximum speed and at large angles of inclination of the blades. Chinese ceiling fans are manufactured with an inclination angle of 9-13 °, for medium ceiling fans the angle of inclination reaches 15 °, for expensive ones up to 20 °.
• The ratio of blade surface area to air flow - The larger the blade surface area, the more air the ceiling fan mixes. However, if the surface area of ​​the blade is too large, there will not be enough space between the blades for sufficient air intake. Some ceiling fans with unusually wide blades (for example, made in the form of palm leaves) or with more than six blades cannot mix the required amount of air. This is due to their low productivity. This relationship affects performance from negligible to significant (depending on measurement accuracy). Contrary to popular belief, the number of blades does not directly affect the performance of ceiling fans. Most 3-blade ceiling fans will mix more air than 4-blade ceiling fans, provided they run at the same speed.
• Height of the ceiling fan relative to the ceiling - If the ceiling fan blades are close enough to the ceiling, the ceiling fan will mix less air than originally calculated. Therefore, the desire to install a ceiling fan as close to the ceiling as possible, or even without a rod at all, leads to a significant decrease in performance. The distance the fan should be installed from the ceiling is directly related to its moving air potential. To achieve maximum performance, ceiling fan manufacturers recommend choosing a distance from the ceiling to the blades of at least 610mm. Unfortunately, at home, these distances are impossible (based on the height of the ceilings and safety precautions), but they are easily applicable to warehouse, industrial premises.

In addition to all of the above parameters, there are other parameters that affect the efficiency of a ceiling fan.

• Height of the ceiling fan relative to the observer - the closer the ceiling fan is to the observer, the more air flow that observer will feel.
• Tilt angle of ceiling fan blades with respect to the vertical axis - some manufacturers of ceiling fans design their blades in such a way that the tilt angle is negative, that is, the angle between the rod and the blade is less than 90 °. This design increases the area of ​​the room that the ceiling fan has a direct effect on and increases the fan efficiency perceived by people in the corners of the room, as well as reduces exposure to people directly under the ceiling.
• Indoor humidity - since the main task of a ceiling fan is to create a cooling effect, that is, evaporation of humidity (both sweat and humidity in the room), we can say that the efficiency of the ceiling fan is directly related to changes in humidity in the room. In rooms with low humidity, the ceiling fan is less efficient than in rooms with high humidity. This property is evident in cold, damp rooms.