Cooling fans are supposed to bring fresh air into the room. They are designed to rotate using a motor. However, this fan uses electricity to function. Cooling fans can be more useful if they are used to light our rooms by converting the mechanical energy produced by the motor to mechanical energy.
We can use the motor that rotates the fan and a dynamo to generate a back emf which can be stored and used for lighting or used directly for lighting instead of storing it. A motor converts electrical energy into mechanical energy of rotation. Some motors can be operated as generators to convert mechanical energy into electrical energy.
It is approximated that homestead fans produce heat of up to 100farenheight. This is enough heat that converted to electrical energy would be enough to light a house.
Kinetic energy for an object at rest is zero. This is because kinetic energy is given by
E=1/2mv2
P=dE =1/2v2dm/DT
it
As the mass flow rate is given by:
dm = ƿAdx
dt dt
and the rate of change of distance is given by
dx =V
dt
we get dm/dt=Ƿav
hence power can be defined as p=1/2ƿAV3
Where:
E = kinetic energy
m = mass of the object
t = time
V = velocity of the body
Ƿ= density of the body
A= area
At rest, the velocity of the body is zero, and hence the substituting v with zero the kinetic energy at rest becomes zero.
We can use a dynamo to convert mechanical energy into electrical energy and produce an alternating current which will be used to light the room. A fan has a motor inside which has a stator and a rotor which helps the motor to rotate.
The stator in the fan motor has some metal plates inside it. It also has some equally spaced coil arms in the perpendicular direction towards the motor axel. In most fans the number of this arms amount to three.
We surround the plates with magnetic coils which will help detect an electromagnetic force around it. The magnetic coils are also connected to a power distribution controlling circuit for converting the back EMF sensed and received by the magnetizing coil into electric power.
The rotor is mounted on the motor axel when it rotates and cuts through the magnetic lines, and a back emf is produced in the induced magnetic field, the induced emf is converted into power by the power distribution controlling circuit for output.
The rotor also has some magnetic objects around it. It is connected with some connecting parts in which to fix the illuminating device, in this case, the bulb through the use of some connecting wires or attaching a frame with several blades in which at the bottom of the blade an illuminating media will be connected, i.e., the bulb.
When power is turned on, and the motor rotates, the rotor cuts through the magnetic field lines and thus producing a back emf in the induced magnetic field.
The emf is then converted into electrical power by the circuit controlling the power distribution which is connected to the illuminating unit, and at this point, the power the illuminating unit lights up.
The distribution unit is electrically connected with the bulb or the illuminating unit at the bottom. This power drives the bulb as long as the circuit is not broken and hence the bulb can produce light without an additional source of power.
Also, if there was a need to store this power, a device such as a rechargeable battery or lead-acid cell is used. An energy saving driver controlling unit is used, and it should be able to detect the polarity of motor rotation. It receives the input voltage and controls the time when the magnetizing coil should be on.
The battery is connected to this energy saving driver circuit and the power so that when the power goes off, or the external power supply is cut off the battery can supply the stored power to the bulb and the bulb continues to light.
As shown in the sketch above, when the switch is turned on, the current flows to the fan and the motor inside the fan start to rotate. This, in turn, causes the fan to rotate and hence the dynamo. The kinetic energy produced by the dynamo is converted to electrical energy and hence producing some power that makes the illuminating element to produce light.
In case of a power storage device such as a battery, it is placed in between the circuit and the illuminating element as shown in the sketch below.
The use of fans as a source of light has a lot of merits since there are no expenses incurred and in some way, it recycles the power that would have been emitted to the environment in the form of heat energy and thus be being of many advantages to the consumer and the environment.
