Normal Fans vs BLDC Ceiling Fans

Normal Fans vs BLDC Ceiling Fans

Ceiling fan is the most widely used domestic cooling appliance in India. These machines usually run for hours and are often known to be energy hoggers. They make up a large percentage of the total residential energy consumption in tropical countries like India. In such a scenario, the advent of BLDC fans in the market is helping change the situation for the better by promoting energy efficiency. Compared to conventional ceiling fans, BLDC fans are much more technologically advanced. Everything – from the motor to the fan blades – has been optimized in the design of these new generation fans to maximize performance and minimize energy consumption.

Motor

Conventional ceiling fans either run on single phase induction motors. These motors consist of a rotor and a motor. When a single phase AC is supplied to the coil windings of the stator, the alternating current begins to flow through the stator. An alternating magnetic flux is generated in the motor – once the field builds up in one phase of the motor and drops to zero, and another magnetic field rises in the opposite direction and falls again. This is a continual process which causes the coils to rotate. Thus, a single phase induction motor cannot self-start. A capacitor is required to overcome this issue. These motors rely on mechanical commutation which inevitably leads to energy loss.

Contrary to this, BLDC motors use electronics along with the stator and rotor. Also, these motors use permanent magnets in the rotor instead of electromagnets. Back EMF and sensors are used to detect the position of the magnets. BLDC motors are powered by a DC electric source through an integrated inverter system that creates an AC flow to rotate the motor. The AC flow here doesn’t take a sinusoidal waveform but a bi-directional current that puts no constraints on the waveform. This is possible only with the help of electronic commutator. The absence of physical or mechanical commutator in these motors helps keep energy loss to a minimum.

Energy Consumption

On an average, ordinary ceiling fans consume around 75 ~ 80 W of power, resulting in mounting electricity costs. Furthermore, since these fans use resistance based regulators for speed control, they generate a significant amount of heat, which is a significant cause of energy loss. With BLDC fans you don’t have to worry about these issues. The use of permanent magnets and electronic commutation for increasing and decreasing the fan speed allows for optimal fan functioning. Since no heat is produced, no energy is lost!

Replacing conventional fans with BLDC fans can save you up to 50% in energy costs annually.

The table below shows the wattage consumption of BLDC ceiling fans and ordinary ceiling fans at varying speeds.

Speed (rpm)BLDC Fan (watt)Ordinary Fan (watt)>
1403.814
2107.725
27013.839
31022.748
36035.876

Speed

Normal fans with single-phase induction motors usually have a winding wound of 16, 18, 20, or 22 poles, which is ideal for lower speeds. The highest RPM of these fans is 360, offering an airflow range of 250-300 m3/min. Stator voltage regulator is used to achieve a wide range of speed control in ordinary fans. This hampers the fan efficiency to a certain extent. Also, it is quite challenging to maintain a steady RPM by regulating the voltage during voltage fluctuations on alternating current.

Unlike conventional fans, BLDC fans can operate smoothly and consistently at all times. The rotor of BLDC motors has low rotor inertia that allows them to accelerate/decelerate as well as reverse directions seamlessly. Furthermore, among all motors, BLDC motors have the highest running torque per cubic inch, and they can operate at highly impressive speeds – above 10,000 RPM! So, you can see the immense gap between the rpm delivery between these two fan variants.

Ceiling Fan - Torque vs Speed - Induction vs BLDC Motor

Ceiling Fan – Torque vs Speed – Induction vs BLDC Motor

These two figures show the starting torque of single phase induction motor (1) and BLDC motor (2). While the starting torque in single phase induction motor the starting torque is as high as 350%. This means that the power required to attain the initial momentum in such motors is relatively higher than a BLDC motor wherein the starting torque is merely 60-70%. Thus, the initial power consumption of single phase induction motors is almost five times higher than that of a BLDC motor.

The table below shows the air flow (CFM) of BLDC ceiling fans and ordinary ceiling fans at varying speeds.

Speed (rpm)BLDC Fan (cfm)Ordinary Fan (cfm)
140467434
210267234
270200160
31013495
36010034

Reliability Factor

The absence of mechanical commutators in BLDC fans makes them more reliable and sturdy. You don’t need to worry about replacing the brushes or repairing motor parts. However, this is not the case with normal fans that require changing the brushes and lubricating the bearings. While conventional fans tend to get noisy and wobbly with time, BLDC fans perform steadily year after year without any such issues.

Remote Control

BLDC fans come with smart remotes loaded with features like timer, sleep, and boost mode. These intelligent modes enhance the fan performance and allow you to customize the fan setting according to your convenience. While the timer mode lets you set a time to automatically switch off the fan, in the sleep mode, the fan speed gradually reduces when the inmates of the house are asleep. The boost mode increases the fan speed for an enhanced cooling effect around the room. Ordinary fans do not come with remote control systems, and hence, everything needs to be done manually.

Atomberg’s Gorilla Ceiling Fan is India’s one of the most energy efficient fan. It runs on BLDC technology and consumes only 28 Watts of power which is way less than the energy consumption of a conventional fan.

Here’s a comparison of the energy consumption and annual savings of Gorilla fans vs ordinary fans.

WattageEnergy use*Electricity cost
Gorilla Fan28134.4806.4
Ordinary Fan753602160

*Note :  Numbers have been calculated on an annual basis, with an average of 16 hrs running time/day for 300 days.

You can clearly see that with BLDC Gorilla fans you can save as much as Rs. 1353 annually.

References

So, how about bringing in the super-efficient BLDC tech to your home?

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