Chapter 1
Introduction
CHAPTER 1
Introduction
1.1.
Overview
Ceiling fan is one of the most common appliances in Indian household. Being a
tropical country, India relies a lot on ceiling fan and there is a ceiling fan in every room
in the country. A fan is defined as a rotary bladed machine maintaining a continuous flow
of air to provide a cooling sensation that people love. Air flow is continuous as the air
flows steadily into, through and out of fan. A fan has a rotating housing fitted with motor,
carrying blades of some kind. These blades exert forces on the air, thereby maintaining
the flow and raising the total pressure. Ceiling fans are made up of a few basic parts
shown in Fig.1.1, the base plate, the motor (with housing) and blades. The parts work
together to provide the cooling sensation.
Fig. 1.1: Parts of ceiling fan
When we turn on the fan, electricity runs through the electrical wiring to the fan's
motor, which begins turning the blades. The blades rotate at a speed and push the air
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Chapter 1
Introduction
down. The rotation of the blades creates airflow throughout the room. The motion of the
blade is very much like an Oar or Blade used to row a boat. Like the Oar displaces water
and the boat moves ahead, the blade of the ceiling fan pushes the air downwards. The
cooling sensation that we feel when we stand under a fan is also quite interesting.
Ceiling fan vibration is the motion displaced from a position of equilibrium. Most
vibrations are undesirable in machines and structures because they result in noise,
increased stresses, energy losses and human discomfort [24]. Ceiling fan noise is defined
as sound unwanted by the listener. Noise is increasingly becoming a major pollutant of
the environment. Noise has a subtle but definitely harmful effect on human health, high
level jarring noise causes fatigue, dizziness, high blood pressure and abnormal heart
rhythms. Prolonged exposure to high level noise leads to noise-induced hearing loss [27].
Most people target only lights when they think about electricity savings, but fans
contribute a lot more to the electricity bills that could be close to 30-40% of the
electricity bills [43]. Compared to lights that are switched on only in the evening (from 6
PM till midnight), ceiling fans are on for most part of the day and even during night. The
total number of hours that the fan is in operation is proportional to the energy
consumption of the fan. At lower amplitude of vibration, lower will be energy
consumption and similarly at higher amplitude of vibration, higher will be energy
consumption. Ceiling fan vibration is accompanied by ceiling fan noise and energy
consumption.
Noise and vibration affect all kinds of engineering structures. The study of noise
and vibration and the interaction between the two is now fast becoming an integral part of
mechanical engineering courses around the world. In ceiling fan causes of noise,
vibration and energy consumption could be different variables that have a great deal of
attention from researchers in the field of noise, vibration and energy consumption.
Noise, vibration and energy consumption are varied from fan to fan due to scatter in
dimension, geometry and material properties of variables. Reduction of noise, vibration
and energy consumption of ceiling fan starts with identification of sources, ranking the
sources and modification in the existing system.
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Chapter 1
Introduction
Previous studies shows the power of Dimensional analysis, Buckingham
theorem, Regression analysis, Linear programming, MS Solver and Artificial Neural
Network to proceed the research work. Dimensional analysis is a method of dimensions.
It is a mathematical technique used in research work for design and for conducting model
test .It deals with the dimensions of the physical quantities involved in the phenomenon.
All physical quantities are measured by comparison, which is made with respect to an
arbitrarily fixed value. Length L, mass M, and time T are three fixed dimensions which
are of importance in various applications. The fixed dimensions are also called as
fundamental dimensions or fundamental quantity. Dimensional analysis is a useful tool
for developing prediction equations of various physical systems. Dimensional analysis
reduces the physical quantities pertinent to a system to dimensionless groups.
Dimensional analysis is based on the Buckingham Pi theorem. The Buckingham Pi
theorem states that “the number of dimensionless and independent quantities required to
express a relationship among variables in any phenomenon is equal to the number of
quantities involved minus the number of dimensions in which those quantities may be
measured [50]. The relationship between various input and output parameters is
unknown. The true relationship is difficult to obtain. Present day tools and techniques
hints towards regression analysis and predictive neural networks. Such functional relation
can explain the joint behaviour and pattern variation between independent and dependent
terms. Any such function obtained will always have the crept error. In view of this exact
value of dependent variable may not confirm to the experimental findings. Regression
analysis incorporates built in procedure for minimization of such error and hence it is a
strong promise for reliance. Regression analysis does not give the fine behaviour of
dependent parameters. In order to understand the fine behaviour of dependent parameters
Artificial Neural Network simulation is the best option. In Artificial Neural Network for
each data, the predicted value is compared to the desired value. Then weights are adjusted
to move the prediction closer to the desired value. Many cycles are made through the
entire set of training data. The weights are being continuously adjusted to produce more
accurate predictions.
The findings indicate that the topic understudy is of great importance as no such
approach of field data based model is adopted for the formulation of mathematical
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Chapter 1
Introduction
models and investigates the effect of independent parameters on the dependent
parameters of ceiling fans in the Indian context.
1.2.
Definition of the Present Work
Statistical analysis of noise, vibration and energy consumption of ceiling fan is
the complex phenomenon. In this complex phenomenon the input variables are nine
ceiling fans, three rooms, three downrods, fan speeds, direction of sensors, blade
variables : number of blades, blade thickness, blade width, blade sweep, blade length,
blade root twist angle, blade tip lift angle, modulus of elasticity of blade material, bearing
variables : bearing bore diameter, bearing outer diameter, bearing width, bearing radius,
basic dynamic load rating, basic static load rating, number of balls, ball size, maximum
runout speed-grease, maximum runout speed-oil, bearing weight, modulus of elasticity of
bearing material, number of bearings, bearing number, clamp variables : clamp length,
clamp thickness, number of holes on clamp, modulus of elasticity of clamp material,
fasteners and shafts variables : number of screws, number of washers and shaft diameter,
field variables : room length, room height, room width, room area, volume of room,
acceleration due to gravity, area of structural member, volume of structural member,
distance between ceiling and plane of
rotation, atmospheric humidity, atmospheric
temperature, air delivery, motor variables : power, current, voltage, motor speed,
capacitor and output variables are noise, vibration and energy consumption of ceiling fan.
Out of so many variables mentioned above we would like to find out which of these
variables are most important for improving the performance of the ceiling fan.
Simultaneously it would be interesting to know the influence of one parameter over the
other parameter.
Nine Orient ceiling fans are selected for the experimentation because more
varieties were available and Orient fan, Delhi, was ready to share the dimension,
geometry and material properties of these ceiling fans.
The experimentation was planed according to Taguchi method (Design of
Experimentation method), Dimensional Analysis, Buckingham Pi Theorem, Regression
analysis, Linear Programming and ANN. Modification included testing of three PZT
actuators by adding developed fixture in ceiling fan assembly for the reduction of
responses (output variables).
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Chapter 1
1.3.
Introduction
Necessity of Present Work
Generally numbers of ceiling fans are observed in the classrooms, hospitals,
offices and residences. Ceiling fan is producing continuous sound during the running
conditions. Noise is a random phenomenon and the majority of the sound emitted by a
fan is random with respect to frequency and time. Thus the sound from ceiling fan is
regarded as noise. Ceiling fan noise is unwanted, undesired sound. Due to this noise there
is a disturbance in the communications during the classroom teaching, high level jarring
noise in the offices is a fatigue, dizziness and noise has a harmful effect on patient’s
health like high blood pressure and abnormal heart rhythms. Prolonged exposure to high
level leads to noise-induced hearing loss. Noise is increasingly becoming a major
pollutant of the environment. Rotating machines parts need careful analysis in order to
prevent the damage from vibrations. Classrooms, hospitals, offices and industries need
the silence and comfort zone. In developing countries like India, 70-80% peoples are
using ceiling fan because ceiling fans are more economical than air conditioners [15].
People feel discomfort when they get sweat in a space with stagnant air.
Therefore, people try to create air breeze around their bodies either naturally or
mechanically to enhance body convective heat transfer. Ceiling fan air motion helps
sweat evaporation and, subsequently brings a feeling of comfort to the body. It is very
difficult for people in developing countries to have an air conditioner to achieve indoor
comfort conditions. In India, ceiling fans are widely used in offices, residences, schools,
colleges and hospitals as an alternative to extend the summer comfort envelope and to
save energy consumption. These fans are affordable, simple in construction, easy to
install, and do not need regular or sophisticated maintenance. Even though ceiling fans
are probably the most common electrical appliance after electric lights in Indian
households and offices, they are rarely mentioned in discussions of noise, vibration and
energy consumption.
This omission results in the loss of opportunity to realize
significant savings in energy by reducing the noise and vibration of ceiling fan. Fans
consume about 20% of the electricity in Indian households and their numbers are
growing rapidly[15].
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Chapter 1
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Every human wants superior quality product with minimum noise and vibration,
minimum energy consumption and good comfort feeling. In fact in the present research
an attempt has been made to incorporate all variables of ceiling fans for the reduction of
noise, vibration and energy consumption of ceiling fans.
1.4.
Objective of Present Work
The specific objectives of the current investigation are as below:

To understand the basic principle of dimensional analysis, reduction of variables,
their statistical modeling and effect within the ceiling fan, through a thorough
literature survey.

To investigate the various ceiling fan parameters to provide more silence and
comfort as well as to reduce the operating cost to the end users.

To measure and analyze the existing noise, vibration and energy consumption of a
Ceiling fan.

To identify the various dependent and independent variables under the
investigation.

To formulate the dimensionless pi term for reducing the number of independent
variables.

To develop an Experimental Data Based Models for the noise, vibration and
energy consumption of a Ceiling fan.

To analyze the formulated models for noise, vibration and energy consumption of
ceiling fan.

To find out the simulated outcomes for the level of dependent variables.

To correlate the experimental output with calculated and simulated output

To find out the sensitivity analysis of the developed model.

To evaluate the influence of various independent variables on the dependent
variables.

To find out the reliability of the developed models.
 To optimize the developed models.
 To reduce the amplitude of vibration, noise level, energy consumption of ceiling
fans.
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Suggested Approach for Present Work
1.5.
Topic Selection
Literature Review
Identification of variables
I/P
Ceiling Fan
Reduction of variables by using dimensional
analysis (Buckingham PI Theorem)
O/P
Instrumentation & Experimentation
Pi terms
(All I/P & O/P data)
Data collection having i/p values and o/p values
ANN Tool simulates the results
1
Formulation of Field Data Based Model which gives
relation between independent and dependent variables
Experimental
output
Validation
of Model
Calculated Results
ANN Output
Analysis of Model
2
By Comparison
Optimization
Sensitivity Analysis
4
Specifying Best set of
independent variables for
the optimal objective
function
Correlation between
Experimental O/P,
Calculated O/P,
Simulated O/P
Satisfied
No
5
Influence of various independent
variables on the dependent variables
Most influencing parameters
Yes
To reduce the influence
From 1,2,3,4,5,6
Stop
Modification
Result and Discussion
Simulated Output
3
Conclusion
Fig.1.2 :Suggested Approach
7
6
Results after Modifications