1. 1
CHAPTER 1
INTRODUCTION
1.1 Statement of Problem
University of Mines and Technology (UMaT), Tarkwa was established in November 2004.
It was actually established in 1952 as Tarkwa Technical Institute. It was recognised to be
Tarkwa School of Mines affiliated to the Kwame Nkrumah University of Science and
Technology (KNUST). Today the campus is poised to meet the challenges of the 21st
century as the University of Mines and Technology (UMaT). Chamber of Mines is the sole
hall of this young university. It has three annexes, Gold Hall, Novotel and Dubai.
Novotel and Dubai suffers from water crises each semester. This is as a result of the
inefficiencies of in water supply by the Ghana water company. This brings about discomfort
to students and cleaners in the rooms, washrooms and kitchen. Cleaners find it difficult to
clean the wash rooms as a result of the water crises. In an attempt to solve this problem, the
hall has provided a borehole which unfortunately breaks down as a result of the intense
pressure on it by student who use it.
This project work is purposed at designing solar powered water pumping system to make
water available to students at a lower cost.
1.2 Research Objectives
The objectives of this project are to:
Identify a suitable pump for Novotel; and
Design a solar powered water pumping system that will make water readily available
to students and cleaners at the hall.
1.3 Methodology and Scope of Work
This project work is limited to the selection of a suitable pump and the number of modules
s required to power it. The methods used include;
2. 2
Literature review on existing Solar Powered Water Pumping Systems;
Consultation of supervisor, other lecturer and colleagues on Solar Powered Water
Pumping Systems;
Taking dimensions of Novotel and Dubai; and
Drawing of proposed design with AutoCAD 2012.
1.4 Facilities Used
University of Mines and Technology library
Internet
Tape measure and ranging poles
AutoCAD 2012
1.5 Organisation of Work
This work consists of five chapters. Chapter 1 is an introduction to this work, it comprises
of the problem definition, objectives, methodology and organisation of work. Chapter 2 is
a review of existing literature about this work and history of utilisation of solar energy.
Chapter 3 shows the components used for this project. Chapter 4 shows the proposed design
and calculations. Chapter 5 presents the conclusions and recommendations.
3. 3
CHAPTER 2
LTTERATURE REVIEW
2.1 Introduction
This chapter seeks to review documents regarding Solar Powered Water Pumping Systems
(SPWPSs). The chapter consists of a brief history of solar energy, definition of relevant
terms, introduction to solar powered pumps, relevant information of other (energy sources)
pumps, advantages and disadvantages of other pumps, compare other pumps with solar
pumps, research information on solar pumps, areas of use of solar pumps and advantages
and disadvantages observed in those areas.
2.2 History of Solar Energy
One may think the use of solar energy is a recent discovery, but actually its dates back to
the 7th century B.C where magnifying glass was used to concentrate sun rays to make fire
or burn ants. In the 3rd century B.C the Greeks used burning mirrors to light touches for
religious purposes. As early as 212 B.C, the great scientist Archimedes used the relative
properties of bronze shields to concentrate sun rays to burn wooden war ships at sea.in the
6th century sun rooms were so common that Justinian code initiated ‘sun rights’ to ensure
individual access to the sun. In the 1830s, Swiss scientist Horace de Saussure built the first
solar collector which he used to cook food during his South Africa expedition. In 1838,
French scientist Edmond Becquerel discovers the photovoltaic effect while experimenting
with an electrolytic cell made up of two metal electrodes placed in an electricity-conducting
solution, electricity generation increased when exposed to light. During the 1860’s August
Mouchet (French mathematician) proposed an idea of a solar-powered steam engine. He
went on with his assistant Abel Pifre to construct the first solar powered engine in the next
two decades. Albert Einstein’s paper on photoelectric effects was published in 1905 and
won a Nobel price on it in 1921. In 1958, the Vanguard I space satellite used a small (less
than one watt) array to power its radios. Later that year, Explorer III, Vanguard II, and
Sputnik-3 were launched with PV-powered systems on board. Despite faltering attempts to
commercialize the silicon solar cell in the 1950s and 60s, it was used successfully in
4. 4
powering satellites. It became the accepted energy source for space applications and remains
so today (Anon., 2002).
2.3 Definition of Relevant Terms
Solar energy is the energy (heat and light) from the sun;
Pump is a mechanical device that raises, transfers, delivers or compresses fluids by
either suction or pressure or both;
Photovoltaic cell is a device used to harvest solar energy from the sun and convert it
to electricity;
SPWPSs is solar powered water pumping systems;
TRNSYS is a simulation program used in in renewable energy engineering and
building simulation for passive as well as active solar design.
2.4 Solar Powered Pump
A solar powered pump is basically a pump whose source of energy is energy from the sun.
Energy from the sun (light and heat) is tapped by a solar collector (photovoltaic cell) and
converted into electricity that powers a prime mover which transfers the power into torque
and angular velocity which turns the blades connected to the shaft of the pump.
2.5 Advantages and Disadvantages of Pumping Techniques
There are so many pumping techniques used over the world, from a small farm to big
industries. These techniques are selected as a result of the following advantages and
disadvantages shown in table 2.1;
5. 5
Table 2.1 Advantages and Disadvantages of Various Pumping Techniques
Pumping technique Advantages Disadvantages
Head pump It can be
manufactured
locally
It is easily
maintained
It is not expensive to
buy or manufacture
It requires no fuel
Flow rate is low
Loss of human
energy and time
It is inefficient with
regards to boreholes
Diesel pump It is easy and quick
to install
Initial capital cost is
low
It is the most widely
used in the world
Can be moved from
one place to another
Cost of fuel is high
Maintenance cost is
high
It has short life span
Noise and fumes are
not environmentally
friendly
Solar pump It requires low
attention
It is easy to maintain
It is easy to install
It has a long life span
high initial capital
cost
water storage is
required for cloudy
periods
skilled technicians
are required for
repairs
(Source: Anon, 2003)
6. 6
Table 2.1 Advantages and Disadvantages of Various Pumping Techniques continued
Pumping Technique Advantages Disadvantages
Wind pump it requires low
attention
it is easy to maintain
it has a long life span
it requires no fuel
Water storage is
required for less
windy periods
It can be destroyed
when the wind is too
much
System design and
project planning
needs are high
It is labour intensive
Animal driven pump Animal dung may
be used for cooking
fuel
Cost of animal
labour is low
Animals are more
powerful than
human
The animals need to
be feed all year
Animals may be
diverted to other
activities such as
ploughing
Hydraulic pump It requires low
attention
It is easy to maintain
It lasts long
It is highly reliable
It requires specific
site conditions for
operation
Low output
(Source: Anon, 2003)
2.6 Relevant Research Information on Solar Powered Water Pumping Systems
Under India meteorological conditions, Pande P. C. and a group of scientists designed,
developed and texted SPWPSs for drip irrigation. In the design, a 900W photovoltaic arrays
and an 800W DC monoblock pump were used. It was reported that the SPWPSs can deliver
water at a pressure of 70kPa- 100kPa pressure at the delivery side with a discharge of 3.4-
7. 7
3.8l/h through each dipper during different hours of the day. A payback time of six years
was reported for the work. It was also reported that at areas off electricity grid, SPWPSs are
more suitable for low and medium water pumping head. Additionally, it was concluded that
SPWPSs are economical in operation only during peak sunshine hours. (C. Gopal et al,
2013)
In similar investigation, Chaurey A. and a group of scientists discussed the field experiences
in India. It was realised that the SPWPS operated for two years continuously without
breakdown except for a few loose electrical wires. Also it was realised that SPWPSs can be
used to replace existing hand pumps. It was suggested that SPWPSs are feasible for small
villages of about 500 provided there are a few back-up hand pumps. Furthermore, SPWPSs
can be of interest under Clean Development Mechanism (CDM) and contributes to
sustainable rural development. In conclusion, there is a big a bid potential in CO2 mitigation
by using SPWPS’s in India. (C. Gopal et al, 2013)
Using batteries for sprinkling and dripping irrigation in Egypt, Mahmoud E. and a group of
scientists investigated into performance of SPWPSs. it was concluded that SPWPSs can be
used for pumping water in the agricultural sector. This is because the cost of pumped water
by photovoltaic pump is less expensive compared with grid electricity during peak hours.
Also SPWPSs improves the quality of life and promote socio-economic development in
rural areas. (C. Gopal et al, 2013)
In related work under meteorological conditions in Egypt, Mankbadi R. R. and a group of
scientists reported that small capacity direct SPWPSs are more suitable for domestic use.
In similar attempt, technical feasibility studies was done in Kalabsha village in the lake
Lasser region of south Egypt by Qoaider L. and a group of scientists. A technical design and
life cycle cost of the SPWPS was calculated. The system was designed to pump 111000m3
of water daily to irrigate 1260ha of land and also power adjacent households. It was
concluded that SPWPSs are economically competitive compared to diesel pump in areas
where national grid is unavailable. (C. Gopal et al, 2013)
In a similar investigation, theoretical and experimental assessment of performance of
SPWPS was done by Hamrouni N. and a group of scientists. The SPWPS consists of an AC
inverter, a submersible motor pump, DC-AC converter and a storage tank. It was reported
8. 8
that the influence of solar radiation will affect the global efficiency of the pump and
maximise performance of the pump as obtained during the middle of the day. However, the
performance of SPWPS was reduced as a result of meteorological parameters such as solar
intensity, ambient temperature, wind velocity and relative humidity. (C. Gopal et al, 2013)
An analytical model was developed in USA by Kou S. A. and a group of scientists for
predicting long term performance of directly coupled SPWPS in six different places
(Abuquerque, New Mexico, Wisconsin Seattle and Washington) and compared to TRNSYS
model. It was reported that the model predicts performance with a root mean square of 3-
6% compared to the TRNSYS model. It was proposed that the new model can be used for
designing and forecasting the long term performance of SPWPS over monthly or annual
periods under US climatic conditions. (C. Gopal et al, 2013)
In another work, the performance of a 1.14kW SPWPS using centrifugal pump was studied
experimentally by Chaudratilleke T. T. and a group of scientists. It was reported that the
overall efficiency of the system was 1.6% which was found to be due to low efficiencies
with photovoltaic systems. The experimental results were observed to be similar to the
simulated results. It was suggested that the efficiency of the system can be improved by
better system design and load matching. (C. Gopal et al, 2013)
In related work, Badescu V. developed a time dependent model consisting of a photovoltaic
array, a battery, a storage tank, a DC motor and a centrifugal pump. The fraction of water
supplied by the battery is stored in the form of gravitational energy in water proves, which
proves that both the battery and the solar storage tank increase the operation stability
SPWPSs. Also an assessment of the performance of a solar powered irrigation system for
sustainable pasture lands in regions of Northwest China was done. It was suggested that
solar powered irrigation can create considerable opportunities in developing rural areas. (C.
Gopal et al, 2013)
Under Jordan meteorological conditions, performance characteristics of SPWPSs in thirteen
wells was investigated by Hammad M. A. A laboratory SPWPS was developed and its
performance and efficiency was monitored throughout the year. Monthly pumping factor
values were calculated on the basics of experimental results. The pumping factor (a function
of solar characteristics) was used to a design new model. (C. Gopal et al, 2013)
9. 9
2.7 Areas of Use of Solar Pumps
Solar powered pumps are used over the world for many applications, but the three main uses
of solar pumps are village water supply, livestock watering and irrigation.
2.7.1 Village Water Supply
In most parts of the world especially Africa, villages do not get access to clean potable
water. As a result of this problem, villages and small town resort to water from streams,
rain, rivers, lakes and boreholes. Solar water pumps are used in few fortunate villages and
small towns to pump underground (borehole) water into reservoirs for domestic use daily.
The advantages of solar water pump include low maintenance cost, no cost on fuel, low
attention and long life span. The disadvantages of solar water pump to villages is high initial
capital cost, the system is ineffective during cloudy periods and maintenance can only be
done by a trained (technical) person. Figure 2.1 shows a schematic layout of village water
supply. (Anon, 2002)
Fig 2.1 Schematic Layout of SPWPS for Village Water Supply
(Source: Gopal et al, 2013)
10. 10
2.7.2 Irrigation
Irrigation is a very important aspect of agriculture. Irrigation can be natural (rain) or
artificial. Demand for artificial irrigation varies throughout the year as a result of the various
seasons. During the dry season or summer, artificial irrigation is at its peak whiles in the
rainy season it may not be required at all. Hence the solar water pump is under-utilised in
irrigation. The advantages of solar water pump include low cost of maintenance, low
operating cost and low attention is required. The disadvantages of solar water pump is high
cost of installation.
2.7.3 Livestock
Water is very essential to livestock. Farm animals need adequate water to survive. Calves
for example require high quality water to grow. 50 pound/head in weaning weight was
reported as a result of provision of sufficient quantity and quality of water to calves.
Advantages derived from using solar powered pumps in livestock watering are low
maintenance and operation cost, twenty years and more warranty on panels and no fuel cost
for farmers to pay. The downside of using SSPWPSs in livestock watering are high initial
capital cost and low flow rate (Jerkins, 2013).
11. 11
CHAPTER 3
COMPONENT SELECTION AND OVERVIEW
3.1 Introduction
In this chapter, more light will be thrown on the various components to be used in this design
work. The components required for this work and the number needed is shown in table 3.1
Table 3.1 Components and the Unit(s) Required.
Components Unit(s)
Centrifugal Pump 1
AC motor 1
Pump controller 1
Inventor 1
Solar PV cells The number of modules will be determined
in solar sizing in the next chapter
Sand separator 1
Check valve 1
Float switch 1
Water tank The capacity of the tank will be determined
in the next chapter
3.2 Centrifugal Pump
A pump is basically a device that increases the pressure of a fluid as it passes through it.
The centrifugal pump does so by transferring mechanical energy from the motor to the fluid
via the rotating impeller. The fluid flows from the inlet to the impeller centre and out along
the impeller blades. The centrifugal force thereby increases the fluid velocity and
consequently the kinetic energy is transformed to pressure. Figure 3.1 shows a cross-
sectional view of a centrifugal pump.
12. 12
Fig 3.1 Cross-sectional View of a Centrifugal Pump
(Source: Anon, 2013)
3.2.1 Advantages of Centrifugal Pump
Centrifugal pump is chosen because of the following advantages (Bema, 2009):
Flow is steady;
It has fewer parts making it less bulky;
It is easier to maintain;
It is cheap and easy to install; and
It does not explode when the valve is closed, the impeller just churns the fluid and
produces heat.
3.3 Photovoltaic System
Photovoltaic (PV) system is a renewable energy system which uses photovoltaic modules
to convert sunlight into electricity. The word photovoltaic originates from two words; photo
which means light and voltaic which means voltage.
Photovoltaic (PV) cells are made of special semi-conductor materials such as silicon. Solar
energy comes down on earth in the form of photon (photons are particles representing a
quantum of light or other electromagnetic radiations which carry energy proportional to the
13. 13
radiation). When photons fall on the positively charged solar cells, they are absorbed within
the semi-conductor material which enables them to transfer all their energy to the semi-
conductor material. This makes it possible for negatively charged electrons to bust out of
their atoms. The flow of these electrons is known as current. When metal contacts are top
and below the PV cells, the curzrent is drawn for external use. The current together with the
cell’s voltage (which is as a result of its in-built electric field or fields), defines the power
that the solar cells can produce. Figure 3.2 shows a cross sectional view of a solar PV cell.
Fig 3.2 Sectional View of a Solar Photovoltaic Cell
(Source: Anon, 2014a)
14. 14
3.4 Alternating Current (AC) Motors
An AC motor is a motor that runs on alternating currents. It converts alternating electric
current to mechanical energy. A pump that works on alternating current is called an AC
motor. For an AC solar pump setup, an inverter is needed to convert the direct current
generated from the solar array to alternating current to drive the pump and act as a controller.
An ac motor was selected for this work because the existing submersible pump is powered
by an internal ac motor.
3.5 Inverters
An inverter is a device that converts power produced by solar PV cells into 110/220 AC
power. The DC power produced by the solar PV cells fluctuates as light intensity of the sun
changes, which can damage the pump when used directly. Hence the inverter protects the
pump.
3.6 Float Switch
A float switch is a level detecting device used in tanks to check liquid levels to prevent
overflow. It is used in conjunction with a pump controller to switch off the pump when the
tank is full. It works with a similar principle to the tank of water closet toilet. Below is a
picture of a float switch.
3.7 Check Valve
A check valve is a two port device, one for fluid to enter and the other for fluid to leave. It
is designed to allow unidirectional flow of liquid in a pipe. Reversal of flow is avoided, this
prevents back flow of pumped liquid back into the pump.
3.8 Sand Separator
It is a filtering device used to filter out sand and other particles from water. A cross-sectional
view of a sand separator is shown in Figure 3.3.
15. 15
Fig 3.3 A Cross-sectional View of a Sand Separator
(Source: Anon, 2014b)
3.9 Water Tank
It is the water reservoir that will store water pumped by the pump. All the water pumped
will pass through the tank before its gets into the washrooms for use. By gravity water will
be pumped to the various floors for use by students and cleaners.
3.10 Pump Controller
A pump controller is a device that controls the alternating current (AC) that is powering the
pump. When the solar energy from the sun is low, the pump will be driven by a slowly
rotating motor and the motor speed will increase as the solar energy intensity increases
during the day. Figure 3.4 shows a picture of a pump controller.
Fig 3.4 A Pump Controller
(Source: Anon, 2014c)
16. 16
CHAPTER 4
MAIN DESIGN
4.1 Introduction
In this chapter, the proposed design will be analysed and backed by design calculations
taking into consideration the water demand of Novotel and Dubai.
4.2 Proposed Design
Figure 4.1 shows the isometric view of the proposed design and table 4.1 shows the names
of structures in the design
Fig 4.1 Isometric View of Proposed Design
17. 17
Table 4.1 Names of the Structures in the Proposed Design
4.2.1 Principle of Design
Energy from the sun in the form of photons falls on the solar cell (Photons refer to particles
representing a quantum of light or other electromagnetic radiations which carry energy
proportional to radiation). They are absorbed within the semi-conductor which enables them
to transfer all their energy to the semi-conductor. This makes it possible for negatively
charged electrons to burst out of their atoms. Current is produced as a result of flow of
electrons.
Current in the form direct current (D.C) fluctuates with changes in sun intensity which can
damage the pump. An inverter is installed to convert the D.C current to 110/220 volts
alternating current (A.C) suitable for the submersible pump and centrifugal pump.
Water from the 60 m deep well is pumped to the surface by a 45 m deep submersible pump
to the surface. The water is diverted into two pipes, one for the existing water pumping
system and the other to the new water pumping system. The centrifugal pump in this design
pumps the water through a water filter into a 20 m3
polytank reservoir on top of Novotel
and Dubai, then the water get into the washrooms and kitchens for use through gravity.
A pump controller regulate the pump in conjunction with the float valve, it turns off the
pump when the tank is full and switches it on when a top-up is required.
Number Name of Structures
1 Dubai
2 Polycrystalline panels
3 Pump house
4 Canteen
5 Novotel washrooms and kitchen
6 Novotel reservoir
7 Novotel
8 Junior Common Room
9 Well
18. 18
4.3 Design Calculation and Analysis
The proposed design is based on the calculations and analysis of the situation at Novotel
and Dubai.
4.3.1 Pump Selection
In the previous chapter, the centrifugal pump was selected for this design work because of
its advantages. In this chapter, various specifications of the centrifugal pump such as
discharge, head and power will be calculated.
Pump Discharge
Through research the following information was gathered;
Submersible pump discharge (Q) = 2 × 10 m3
/s;
Delivery pressure of submersible head = 5 bar;
Depth of well = 60 m;
Depth of submersible pump = 45 m;
Submersible pump power = 2 horse power = 1.5 kW;
Height of Novotel and Dubai = 14.4 m;
Diameter of pipe = 5 inches = 0.127 m;
pipeofArea
Discharge
Velocity (Bema, 2009) (4.1)
Cross sectional area of pipe =
4
πd2
(4.2)
Where, d = diameter of pipe = 5 in = 12.7 cm
Therefore cross sectional area =
4
)10(12.7 2-2
= 0.0126 m2
19. 19
Novotel and Dubai are of the same height but friction in the pipes is greater for Novotel
since the length of pipe from the pump to the tank is greater. Therefore Novotel will be
considered for the calculations. The flow of water is diverged into two pipes, so it is assumed
that the discharge in each pipe is half of the submersible pump discharge.
s/m001.0
2
0.002
(Q)Discharge 3
Velocity of flow =
0126.0
001.0
= 0.0793 m/s
In other to determine the type of flow of the fluid, the Reynolds number Re is calculated
Reynolds number (Re) =
ud
(Bema, 2009) (4.3)
Where, is the density of the water = 1 × 10 kg/m3
u is the velocity of flow = 0.0793 m/s
is absolute or dynamic viscosity = 1.14 × 10
d is cross sectional area of the pipe = 12.7 × 10 m
Re = 3-
-23
1014.1
1012.70.0793101
= 88 342.98
Since Re is greater than 4000, the flow of the water in the pipe is turbulent.
The experimental work done by Blasius on smooth pipes yielded the relationship,
Friction coefficient (λ) =
4
1
Re
3164.0
(Mc Keon et al, 2005) (4.4)
=
98.34288
3164.0
20. 20
= 0.018352
Fig 4.2 Schematic Diagram of Pumps and Reservoirs
Bernoulli’s equation is given as
hlZ
2g
u
ρg
P
HZ
2
u
ρg
P
B
2
BB
mA
2
AA
g
(Bema, 2009) (4.5)
Making Hm the subject of the equation,
hl)Z-(Z
2g
u-u
ρg
P-P
H AB
2
A
2
BAB
m (4.6)
Where, Hm is manometric head
PA is the delivery pressure of the submersible pump = 5.5 bar
PB is the atmospheric pressure in the tank = 0
uB
2
= uA
2
is the velocity of the fluid in the pipe = 0.0793 m/s
ZA is the suction head = - 45 m
21. 21
ZB is the delivery head = 17.4 m
Σhl is the sum of head losses (frictional losses + minor losses)
For the purpose of this design there are seven 90° elbow bends, a check valve, changes in
diameter of pipe and a suction and delivery pipe lengths of 100 m and 114.5 m respectively.
Σhl = frictional head losses (hfs + hfd) + valve head losses + abrupt enlargement losses +
abrupt contraction loss + bend losses
From the analysis above on the energy equation,
hl)Z-(Z
ρg
P-
H AB
A
m (4.7)
Darcy’s formula is used to determine the frictional losses in the pipe and it is given by
2gd
4flu
h
2
f hf = (Massey, 2006) (4.8)
Where, 4f = λ
λ is coefficient of friction = 0.018352
l is the length of pipe
u is velocity of water in the pipe = 0.0793 m/s
g is acceleration due to gravity = 9.81 m/s
d is the diameter of the pump = 12.7 × 10-2
m
The energy equation becomes
)kkk(k
gd2
u
gd2
ul
gd2
ul
Z-Z
ρg
P-
H vceb
22
g
2
d
AB
A
m
(4.9)
Where, kb = smooth bend factor = 0.3
ke = abrupt enlargement factor = 0.5
22. 22
kc = abrupt contraction factor = 0.2
kv = valve factor = 0.19
(Bema, 2009)
0.19)0.20.573.0(
9.812
0.0793
9.810.1272
0.0793100018352.0
9.810.1272
0.0793111.40.018352
17.445
9.81101
105-
H
2
22
3
5
m
= 11. 443 m
Population of Novotel and Dubai
The total number of students accommodated by chamber of mines hall annexes, Novotel
and Dubai is about two hundred and eighty. This design takes into consideration the visitors,
sellers and non-resident students who use the washrooms and kitchen. The number of users
vary daily, an assumed number of 140 people is in the analysis. The daily water demand for
Novotel is the total sum of the following:
Water for bathing (Wb);
Water for cooking (Wc);
Water for cleaning the washrooms and kitchen (Wk);
Water for flashing the water closet (Wt); and
Total water demand = Wb +Wc + Wk + Wt + Ww (4.10)
Assuming each student baths twice a day with 15 litre of water for each bath, then total
water used for bathing daily
(Wb) =2 × 140 × 15 = 4200 litres = 4.2 m3
Average water per flash is 13 litres and assuming each student uses the water closet once a
day,
(Wt) = 13 × 140 = 1820 litres = 1.82 m3
23. 23
Assuming each student uses 1 litre of water to cook a day,
(Wc) = 3 × 140 = 420 litres = 0.420 m3
Assuming water used for cleaning the washrooms and kitchen daily is 300 litres
Total daily water demand = 4.2 + 1.82 + 0.42 + 0.3 = 6.74 m3
of water.
A 20m3
water reservoir is used in the design considering the daily water demand. The
polytank can sustain Novotel for more than three days.
Time required to fill the tank =
Discharge
capacityTank
(4.11)
=
001.0
20
= 20000 s
= 333.33 mins. (5 hrs, 33 mins)
Time required to fill the tank is approximately 6 hours
Pump Power
With the flow rate of the pump known, the hydraulic power, theoretical power and motor
power can be calculated. The hydraulic power is given by,
P = ρghQ (4.12)
Where, ρ = 1000 kg/m3
, g = 9.81 m2
/s, h = 10.4369 and Q = 1 × 10 m3
/s
P = 1000 × 9.81 × 11.4369 × 2 ×10-3
= 224.6 W
24. 24
Considering the head, discharge and power, lucky Pro MCP 150-1 with manometric head
of 41 m, discharge of 2.7 × 10-3
m3
/s and power consumption of 0.75kW was selected for
this project
4.3.2 System Power Consumption
The solar photovoltaic panels will supply energy to the centrifugal pump and the
submersible pump.
Total power consumption = motor power + submersible pump power (4.13)
Where, submersible pump power = 1.5 kW
Pump power = 0.75kW
Total power consumption = 1.5 + 0.75 = 2.25 kW
4.3.3 Solar Module Sizing
The number of solar modules to be used is dependent on the load, operational hours, number
of peak hours and the rating of the polycrystalline cells.
Load per hour =
hourspeak
hourslOperationaLoad
(4.14)
Where, load = 2.25 KW
Operational time = 6 hours
Peak hours = 5.5 hours (peak hours in Ghana is between 5.2 and 5.7)
Load per hour = 2.45 KW
Assuming the power rating of a polycrystalline is 400W
Number of modules =
400
2138
= 6.136 modules
25. 25
Number of modules required is approximated to 7
The solar panel produces power at 12 volts which is below the 48 volts required at the
inverter input. Therefore there is a need to connect four 400w panels in series and afterwards
in parallel with the other having the same arrangement. In addition total number of panels
required is 8.
4.4 Cost Analysis
The cost of a 400W solar polycrystalline panel is $ 224, 8 of them is $ 1 792. The cost of an
inverter is $ 140. This sums up to $ 1 932, approximately ¢ 5 023.20. The life span of a solar
panel is about 20 years. Therefore spreading ¢ 3 962 over 20 years, an amount of ¢ 20.93 a
month will be spent on electricity.
Electricity Company of Ghana (ECG) rates for electricity = 0.3067¢/KWh.
Power per month = power × operational hours × days in a month (4.15)
= 2.25 × 6 × 30
= 405 kW
Amount of money spent on electricity = Total Monthly Load × ECG Rates (4.16)
= 405 × 0.3067
= ¢ 124.21
The cost for solar electricity is ¢ 20.93 per month whiles the cost of electricity from ECG is
¢124.21 per month. Therefore it is more economical to use solar panels.
26. 26
CHAPTER 5
SUMMARY, CONCLUSION AND RECOMMENDATION
5.1 Discussion
Dubai and Novotel are annexes of chamber of Mines Hall. The hall suffers from water crises
every semester as a result of the inefficiencies of Ghana Water Company, this makes the
annexes uncomfortable for its occupants.
The number of occupants of the annexes is about two hundred and fifty. It is assumed that
about two hundred and eighty students use the facility taking into consideration the non-
resident students who visit the hall and food sellers at the canteen. The daily water demand
for Novotel and Dubai is similar but Novotel is further away from the pump compared to
Dubai, therefore frictional head loses in the pipes will be greater for Novotel , hence Novotel
is used in the calculations. Based on the number of students, the daily water demand was
obtained as 6.74 m3
and a reservoir of 20 m3
was selected since it can sustain the hall for
more than three non-sunny days.
The discharge and velocity of water pumped by the submersible pump are 2 × 10-3
m3
/s and
0.0793 respectively and will take about 6 hours to fill the reservoir. With Bernoulli’s a
manometric head, Hm of 11.4 m3
was obtained.
Based on the discharge of 2 × 10-3
m3
/s, manometric head of 11.44 m and power of 0.2246
kW, a lucky Pro MCP 150-1 with discharge of 2.7 × 10-3
m3
/s, manometric head of 48 m
and power of 0.75 kW was selected for this work
5.2 Conclusions
At the end of the project, a suitable pump, lucky Pro MCP 150-1 with manometric
head of 48, discharge of 2.7 × 10-3
m3
/s and power consumption of 0.75kW was
selected for Novotel and Dubai based on the required head and water demand of the
hall.
27. 27
As a result of availability of water at each floor for students and cleaners, sanitary
condition at the hall was improved.
The cost for solar electricity is ¢ 20.93 per month whiles the cost of electricity from
ECG is ¢124.21 per month. Therefore it is more economical to use solar panels.
5.3 Recommendations
It is recommended that;
The discharge of the submersible pump should be increased in other to reduce the
operational time.
Further research should be done on the surface of the panel since dirt blocks sunlight
from reaching the surface of panel reducing its efficiency.
28. 28
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Anon. (2003), “The History of Solar”,
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2014
Massey, B and Ward-Smith, J. (2006), Fluid Mechanics, Francis and Taylor Group, New
York, USA, 8th
edition, 278 pp.
Bema, B. A. (2009), “Design of A Water Supply System For The Chamber of Mines Hall
(Novotel), UMaT”, Unpublished BSc Project Report, University of Mines and
Technology, Tarkwa, pp. 8-22.
Gopal C., Mohanraj M., Chandramohan P. and Chandrasekar P., (2013), “Renewable
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Anon. (2013), “The Centrifugal Pump”,
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Jenkins, T. (2013), “Designing Solar Water Pumping System for Livestock”,
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Anon. (2014a), “Solar Photovoltaic Technology”,
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29. 29
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