MEE 522 DESIGN PROJECT
Design of Solar-Powered Corn Grinding Machine
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Design of Solar-Powered Corn Grinding Machine 2011
Department of Mechanical Engineering
University of Benin
Design of a Solar Powered Corn Grinding Machine
By
September 2011
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Design of Solar-Powered Corn Grinding Machine 2011
Table of ContentsIntroduction...........................................................................................................................................1
The Corn Grinder...............................................................................................................................2
The Components of the Grinding Machine........................................................................................2
The Solar Panel..................................................................................................................................3
How the Panel Works....................................................................................................................4
Economic Importance of the Solar-Powered Corn Grinding Machine...............................................5
Literature Review..................................................................................................................................7
Design (CONCEPTUAL DESIGN, DESIGN CONSIDERATIONS, POWER CALCULATIONS AND COST ANALYSIS)...........9
Isometric Diagram of the Corn Grinding Machine...........................................................................10
3D View of the Machine..................................................................................................................11
The Design Concept.........................................................................................................................12
The Solar Power System..................................................................................................................12
The Solar Panel............................................................................................................................13
Solar Regulators...........................................................................................................................14
The Battery Bank.........................................................................................................................14
Power Inverter.............................................................................................................................15
Design Considerations.....................................................................................................................15
Power Calculations..........................................................................................................................16
Solar Panel Rating........................................................................................................................17
Cost Analysis....................................................................................................................................19
Economic Analysis...............................................................................................................................20
Registration (Business Name)..........................................................................................................20
Obtaining Licenses, Permits and approvals.....................................................................................21
Selection of Technology...................................................................................................................21
Advertisement.................................................................................................................................22
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Design of Solar-Powered Corn Grinding Machine 2011
Chapter One
Introduction
Corn is a cereal grain and or maize is a common name for cereal grass widely
grown for food and livestock fodder. It is a natural source of protein as well as
a source of carbohydrates and is made into many different kinds of foods. It is
a staple food in Nigeria and serves as a rich source of carbohydrate for both
man and livestock; as it can be used to prepare corn starches for both man and
animals.
Corn can be grounded either wet to produce paste, or dry to produce corn
flour depending on the intended use.
It is better to carry out this process with the use of electricity to power the
corn grinding machine due to the over-dependence on petroleum fuel (which
generates carbon waste to the atmosphere). This carbon waste generation is
reduced and a cleaner means of carrying out this process is established. And as
a result of the unstable power supply in the country an alternative means of
power source is considered here using solar panels to power the grinding
machine which is cleaner and environmental friendly.
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Design of Solar-Powered Corn Grinding Machine 2011
The Corn Grinder
A grinder is a machine for producing fine particle size reduction through
attrition and compressive forces at the grain size level and this requires a lot of
energy.
The corn grinder makes flour or paste (when mixed with water) out of corn and
is a machine that is designed to grind corn with the use of stone grinder and is
powered by a solar panel which is a much cleaner source of powering the
grinding machine and on a long run more economical.
The Components of the Grinding Machine
The corn grinder was designed to be simple with fewer components making it
a cheaper option to the normal corn grinding machines available. The machine
comprises of the following components:
The Hopper: this is a large funnel shaped dispenser or container for storing
and dispensing the grain into the grinder.
Shaft: this is a rotating part used to transmit torque required in grinding the
corn from the motor to the grinder.
Grinder: this is the tool that performs the grinding. The grinder used in the
machine is a stone grinder. Stone grinders have two circular grinding stones.
One stone turns against a stationary stone. Grooves are cut into the stone
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Design of Solar-Powered Corn Grinding Machine 2011
radiating out from the centre of the stone to the ends. These grooves become
shallower as they near the ends of the stone, until they disappear at the outer
edges. When grain is ground, it falls through a channel into the centre of the
two stones. As the stone rotates, it pulls the grain out through the channels
where it is ground. The flour falls out the outer edges of the two stones.
The Motor: is the machine that converts electrical energy into rotary motion
and is used to drive the shaft which in turn rotates the grinder to grind the
corn.
Bearing: this serves as housing for the shaft and it also supports the load of the
shaft thus reducing the weight acting on the motor from the shaft.
Feeder: Grounded or processed corn is collected from the feeder.
Knob: this is used to adjust the spacing between the grinding stones to
determine the smoothness of the grinding.
Base: this serves as a support for the machine.
The Solar Panel
Solar radiation is a general term for the electromagnetic radiation emitted by
the sun. We can capture and convert solar radiation into useful forms of
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Design of Solar-Powered Corn Grinding Machine 2011
energy, such as heat and electricity, using a variety of technologies but in this
case we are converting to electricity.
The basic principle of solar energy is that every location on Earth receives
sunlight at least part of the year. The amount of solar radiation that reaches
any one "spot" on the Earth's surface varies according to these factors:
Geographic location
Time of day
Season
Local landscape
Local weather
In this case we are capturing the energy from the sun using solar panel and
converting to electricity.
How the Panel Works
As the sunlight strikes the silicon cells in the panel, it excites the electron which
are knocked free to form electric current, metal contact points carry the
current away and completes the circuit. This power is then transferred to a
rectifier (solar regulator or charge controller) and to a battery which stores the
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Design of Solar-Powered Corn Grinding Machine 2011
charge or current and then to an inverter which converts the DC voltage to AC
voltage.
Economic Importance of the Solar-Powered Corn Grinding
Machine
Due to the fact that corn meal is highly nutritious and is an everyday need for
most home and farmers who intend to use for their animals, there is a great
need for grinding corn and hence the need of a grinding machine.
The flour you buy in the store - even the whole wheat kind - is dead. Once
ground, wheat loses all of its nutrients within 12 hours. Ground wheat left out
longer than a week will even become toxic (always either freeze your freshly
ground flour or better still, grind just enough for your daily use). To combat
this, manufacturers will add preservatives and vitamins to store-bought flour
and breads. These preservatives wind up in your body and stay there for a long
time. You can avoid these scary chemicals by grinding your own fresh flour in a
grain mill at home.
Producing energy can be dirty work. Carbon emissions, coal slurry, nuclear
waste, and other pollutants can wreak havoc on the environment, and cause
health problems. And many energy sources are in limited supply.
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Design of Solar-Powered Corn Grinding Machine 2011
This solar-powered corn grinding machine is also of high importance to the
economy because it provides an alternate means of grinding corn different
from the conventional use of diesel powered engines which are very noisy and
releases carbon waste to the atmosphere. This is a gas that causes greenhouse
effect and is hazardous to the environment. And in addition to this the
machine production will serve as a source of income to the designer and also
provide jobs to persons who will be in charge of operating them.
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Design of Solar-Powered Corn Grinding Machine 2011
Chapter Two
Literature Review
Early grain mills were driven by paddle wheels which were attached to a shaft that turned
the millstone. The millstone was on top of a similar sized stone that was stationary and this
simple arrangement worked well in areas where water ran swiftly. There was no gear which
was good because of maintenance, but it was also a disadvantage because there was no
consistency in the speed of the mill. During the Roman Empire, they advanced to vertical
wheels with some estimated at 2.4 to 3.2 tons per hour. By 1086 in England, a census was
taken and there were 5,624 water-powered flour mills.
The classical grain mill is designed to be driven by water. Some were driven by livestock
while others were driven with slave labor. At the end of the eighteenth century, Oliver
Evans revolutionized grain mills when he invented, patented and promoted a fully
automated mill.
Modern mills usually use electricity to turn heavy steel or cast iron flat and serrated rollers
to separate bran and germ from the endosperm. White flour is made of the endosperm.
Many bakers still prefer the stone-ground flour because of its texture. The bakers fear that
much of the nutritional value is lost in the heat created by the metal rollers of the modern
flour mills.
The modern corn mills can produce enormous amounts of product, but in the production
process, there is often lost the goodness of the whole-grain. Whole-grain products can be
found in the grocery store, but it is difficult to find what you are truly looking for in terms of
texture, flavor and cost.
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Design of Solar-Powered Corn Grinding Machine 2011
Today, we have advanced to the modern home grain grinders which can produce virtually
the same and better quality flour as the modern gristmills. Modern grain mills are easy to
use, lightweight, adjustable to a special grind, can produce as much or as little as needed,
and have a consistent quality.
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Design of Solar-Powered Corn Grinding Machine 2011
Chapter Three
Design (CONCEPTUAL DESIGN, DESIGN CONSIDERATIONS, POWER
CALCULATIONS AND COST ANALYSIS)
This corn grinding machine is designed for simplicity with fewer components to
reduce the power needed to run. This machine comprises of the following
parts.
AC Motor
Grinder (Stone Grinders)
Hopper
Shaft
Feeder
Bearing
Knob
Base
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Design of Solar-Powered Corn Grinding Machine 2011
Isometric Diagram of the Corn Grinding Machine
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Design of Solar-Powered Corn Grinding Machine 2011
HopperGrinding CompartmentShaft
BaseFeeder
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Design of Solar-Powered Corn Grinding Machine 2011
3D View of the Machine
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Design of Solar-Powered Corn Grinding Machine 2011
The Design Concept
Corn is fed through the hopper and from the hopper goes to the grinding
compartment and through the stationary stone. Grooves are cut into the stone
radiating out from the centre of the stone to the ends. These grooves become
shallower as they near the ends of the stone, until they disappear at the outer
edges. When grain is ground, it falls through a channel into the centre of the
two stones. As the stone rotates, it pulls the grain out through the channels
where it is ground. The flour falls out the outer edges of the two stones.
There is a shaft which passes a bearing connecting the moving stone to the
motor (AC), the motor receives power form a solar panel.
As current comes from the solar panel to the motor, the motor rotates and this
rotary motion is transmitted by the shaft to the rotating stone, and as the corn
come in through the groove of the stationary stone, the rotating stone crushes
the grain against the stationary stone. The smoothness can be adjusted with a
knob, the knob reduces the spacing between the stones.
The Solar Power System
This generates the power that is used to drive the machine. And it comprises of
the following components:
The Solar Panel which contains
photovoltaic cells
The Solar Regulator or
Charge Controller
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Design of Solar-Powered Corn Grinding Machine 2011
The Solar Panel
The solar panel converts sunlight into DC power or electricity. They are
classified according to their rated power output in Watts. The solar panel uses
photovoltaic cell (a device used to convert solar radiation directly into
electricity). The most common type is single crystal silicon solar cell. A standard
photovoltaic cell is a thin semiconductor sandwich, with two layers of highly
purified silicon. A semiconductor is a crystal that is constructed in such a way as
to yield certain specific properties that can be used in electrical circuits.
Transistors are made of semiconductors. Microprocessors are as well. In fact,
the entire field of modern electronics uses various forms of semiconductors, so
the implications are worldly. If you connect an electrical circuit to your
semiconductor sandwich when sunlight is shining on it, electricity flows.
Solar Regulators
The solar regulator or charge controller ensures that the battery is charged
properly and not damaged and that power is not lost or discharged. It feeds
The Battery Bank
Inverter
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Design of Solar-Powered Corn Grinding Machine 2011
current into the battery bank at the required voltage. Good solar regulators or
charge controllers draw the best performance out of the batteries and are very
important for economics because they influence efficiency. It also prevents
batteries from overcharging, overcharging causes gassing and loss of
electrolyte resulting in damage to the batteries.
This solar regulator will include a Low Voltage Disconnect feature, which will
switch off the supply to the load if the battery voltage falls below the cut-off
voltage. This prevents the battery from permanent damage and reduced life
expectancy.
They are rated by the amount of current they are able to receive from the solar
panel.
The Battery Bank
Deep cycle batteries will be used in system because they are designed to be
discharged over a long period of time (e.g. 100 hours) and recharged hundreds
or thousands of times, unlike conventional car batteries which are designed to
provide a large amount of current for a short amount of time.
Power Inverter
The power inverter is the main component of any independent power system
which requires power. The power inverter will convert the DC power stored in
the batteries and into AC power and then transmits this power to the motor.
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Design of Solar-Powered Corn Grinding Machine 2011
Design Considerations
The major factor considered in the design of the machine is cost and thus the
entire component selected were as small an efficient as possible due to the
fact that the machine will be powered using solar power which could be very
expensive if the machine requires a very high power to run.
The other factors considered are:
Shaft size and material: the shaft selected is a 1inch diameter shaft made
from mild steel.
Type and size of bearing used: a pillow block bearing of 1inch internal
diameter is selected.
Operation and control: turning the machine on/off will done using a
switch thus making it easier to operate
Maintenance procedures: since the machine was designed with fewer
parts, it is easy to maintain as it contains no hidden part.
Corrosion and wear of the material: as a way of preventing the material
from corroding the metal used in manufacturing the machine will be
painted
Motor capacity: an AC motor capacity of 500watts, 1200rpm is selected.
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Design of Solar-Powered Corn Grinding Machine 2011
Availability of solar energy: there is constant energy supply from the sun
to this part of the world and thus is the source for powering the
machine.
Power Calculations
The size of the motor is:
500 watts
0.67hp
1200rpm
50Hz
40µF
2.3Amps
Power-required to drive the motor
In order to size the solar panel, we need to determine the size of the motor
and also the amount of hours the machine will work per day.
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Design of Solar-Powered Corn Grinding Machine 2011
Device Power Rating Estimated RuntimeWatt Hour (WH)
Consumed
AC Motor
500 watts
0.67 hp
220V
Six (6) Hours per day 3000
Table 1 - Power Rating of the Electric AC Motor 1
Solar Panel Rating
The number of charge hours expected for the solar panel is 8hours.
Power Rating of the solar panel = Daily usage ÷ Charge hours
3000WH ÷ 8 = 375watts
Accounting for inefficiencies we add by 20%
375 × 1.20 = 450watts
The total number of panels needed will be:
450 ÷ 150 =3
Three (3) 150 watts panels will be needed
Amount of Batteries Needed
The 150 watts panel produces 4.4 amps thus
3 × 4.4A = 13.2 A × 8Hrs = 105.6Ah
105Ah batteries, should be discharged to no more than 50%, thus we divide
total amps by 50% of 105Ah = 50Ah.
105.6 ÷ 50 = 2.112
Therefore two (2) 150Ah batteries will be needed
Regulator or Charge Controller Size
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Design of Solar-Powered Corn Grinding Machine 2011
For the 20A regulator
One 150W panel produces around 4.4 Amps.
3 x 4A = 12A
So for Six (3) Solar Panels we will need:
3 ÷ 3 = 1
Therefore we will need one charge controller for the machine.
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Design of Solar-Powered Corn Grinding Machine 2011
Cost Analysis
S/No Part Name Quantity Dimension/RatingUnit Cost
(N)Total Cost
(N)
1Electric AC Motor
1500W, 220V, 0.67hp, 50Hz,
1200rpm15,000 15,000
2Shaft (Mild Steel)
1 1in Dia. By 300mm 2,000 2,000
3Hopper (Sheet Metal)
1 - 1,000 1,000
4Bearing (Journal)
1 1in inner Dia. 5,000 5,000
5Base (Cast Iron)
1 - 5,000 5,000
6Feeder (Sheet Metal
1 - 1500 1,500
7Grinder (Stone Grinder)
1 - 7,000 7,000
8 Knob 1 - 500 500
9Cost of Fabrication
- - 5000 5,000
10Solar panel (PV Cells
3 150W, 4.4A 75000 225,000
11Battery (Deep cycle)
2 150Ah 30000 60000
12Solar Regulator
1 20A 20000 20000
13 Inverter 1 1000W 30000 30000
Grand Total 378,000
Table 2 - Cost Analysis of the Solar-Powered Grinding Machine
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Design of Solar-Powered Corn Grinding Machine 2011
Chapter Four
Economic Analysis
A good design and manufacture of a powerful machine without an economic
value is as good as useless because if a machine cannot meet a need or is too
expensive to obtain, it probably might be in the shelve for long and thus
redundant. Thus it is of high importance that engineers carry out an economic
analysis of a machine before putting it into the market.
From the knowledge of CED, we learnt that for a product to have a market, it
must satisfy a need for which consumers and anticipated users are willing to
pay for. The following steps are taken to ensure economic viability.
Registration (Business Name)
We will ensure that our business name is registered at the state and territory
level of government. This involves registering our business name with the
corporate affairs commission.
Location and Site Selection
In selecting and locating our business site we will take into consideration the
availability of, and proximity to basic amenities like:
Raw materials
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Design of Solar-Powered Corn Grinding Machine 2011
Marketing location
Security
Availability (reliability of power supply)
Possibility of expansion
Obtaining Licenses, Permits and approvals
We will ensure that we find out the licensing requirements that apply to our
new business. The federal, state and local governments are all responsible for
the different licenses, permits, registration and certificate that applies to
businesses.
Selection of Technology
We will ensure we select appropriate technology that will include:
Reduced real and implied cost of technology
Reduced maintenance cost
Capacity of the technology in relation to the expected level of operation
Adaptability and flexibility of the technology
Efficiency of the technology
Lifespan of the technology
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Design of Solar-Powered Corn Grinding Machine 2011
Advertisement
After the economic analysis and design of the machine the next step is to find
means of bringing our product (the solar-powered grinding machine) to the
notice of our prospective buyers. This could be done by the following:
Exhibitions
Showcasing in a showroom
Networking
This will enable us to convince our prospective buyers that our product is the
best.