The document examines the average monthly electricity consumption in the DCPE building area. It analyzes electricity bill records from 2018 for the larger "workshop region" that includes DCPE. This region has a total area of 19,254.99 sqm while the DCPE area is 4,698.26 sqm. To estimate DCPE's monthly consumption, the document calculates the ratio of the two areas and applies it to the workshop region's average monthly consumption of 84,931 kWh. This approach allows estimating DCPE's electricity usage based on its portion of the overall workshop area.

1. 1
CH 1060 Process Engineering Fundamentals
Assignment
Group 13 : Possible Solar Electricity Production Potential for
DCPE Building
Group Members :
170070D : BENARAGAMA B.V.C.M.
170397K : NAOTUNNA L.W.
170230U : IMBULANA S.N.
170611N : SUMANASENA M.A.I.
Date of submission: 28/12/2018
Department of Chemical and Process Engineering
University of Moratuwa

2. 2
With the exponential increase in usage of electric energy across the world, the
scientists and engineers are trying to move towards the methods of electricity production
using renewable primary energy sources. As an island located in Tropical region where the
sunlight (solar energy) is available most of the time throughout the year, apresent trend in
Sri Lanka has been developed to extract the energy from solar radiations to fulfill the energy
requirements in large, medium and even in domestic scale.
One of the facts, one decade ago there was as a drawback for the solar electricity
production was, the method available being not efficient enough to meet the requirements
when considered with principal and the maintenance costs of solar panels. But over past
years a rapid development of the technology has occurred and it is not a loss anymore to
obtain electricity from solar panels instead of obtaining electricity from the national grid.
Technologies have been developed by the manufacturers so that in a case of excess
electricity production, the excess amounts can be sent to the grid contributing the national
production of electricity within the country.
Objectives
The main objective of the project was to experiment on the feasibility of the
production of needed amount of electricity within the department premises. The project
report is planned and interpreted on following topics
1. Different Technologies of Solar Energy Production
2. Examining the average monthly consumption of electricity within the DCPE
building area
3. Presenting data from Solar Energy manufacturers needed for the project
4. Calculating maximum feasible amount of energy that can be produced
within the DCPE building area
5. Predicting the feasibility of the Project
Introduction

3. 3
SECTION 01
DIFFERENT TECHNOLOGIES OF SOLAR ENERGY
PRODUCTION

4. 4
01. Different Technologies of Solar Energy Production
Solar energy is the cleanest, most abundant renewable energy source available.
Today's technology allows us to harness this resource in several ways, giving the public
and commercial entities flexible ways to employ both the light and heat of the sun.
There are 3 primary technologies by which solar energy is commonly harnessed.
1. Photovoltaics (PV) :
• Directly convert light to electricity
2. Concentrating Solar Power (CSP) :
• Use the heat from sun(thermal energy) to drive utility scale, electric
turbines
3. Heating and cooling systems :
• Collect thermal energy to provide hot water and air conditioning
1.1 : Solar PV Technologies
If we are looking for a solar power system, the major part of that system is going to
be "solar PV (photovoltaic) panels that convert sunlight into electricity using a phenomenon
called the photovoltaic effect.
There are 3 major types of solar PV technology on the market.
1. Monocrystalline
2. Polycrystalline
3. Thin Film

5. 5
1.1.1 : Monocrystalline Solar Panels
Some think of monocrystalline solar panels as the 'Rolls Royce' of solar PV
technology and the best choice. Monocrystalline is one of the oldest technologies, and more
expensive to make, but this type have the highest efficiency.
These panels can typically achieve 15-20% conversion efficiency in the real world,
i.e. convert 15-20% of the sunlight that hits them into electricity. They are made from wine-
bottle sized single crystals of ultra-pure silicon and sliced up like salami to make individual
wafers.
Monocrystalline solar cells are generally high performance, but because they waste
a bit of space between the cells when they are encapsulated in a solar PV panel (the little
white diamonds in the picture above) they perform about the same (in efficiency and power
terms) as polycrystalline.
Some manufacturers use special techniques to make ultra-high performance
monocrystalline solar PV modules, such as "back surface fields", "laser grooving" and
hybrid technologies. These super high performance mono panels get efficiencies of over
20% – which is amazing. But you do pay about 30% more compared to conventional
monocrystalline solar panels.
The easy way to spot mono solar panels on a roof is to look for the telltale white
diamonds between the cells.

6. 6
1.1.2 : Polycrystalline Solar Panels ( Multi crystalline Solar Panels)
Polycrystalline solar panels are also made from silicon, but the type of silicon used
is slightly less pure and they are cast into blocks rather than sawn from a single crystal. The
fact that the crystals are randomly arranged means that they are visible individually.
Once the polycrystalline ingot is cast, it is sawn into square blocks, and then sliced
into square wafers that are processed to convert them into solar cells.
1.1.3 : Thin Film Solar Panels
Whereas mono and polycrystalline solar panels are made in very similar ways, thin
film solar panels use a completely different method of manufacturing. Instead of creating
solar cells by sawing up large blocks of silicon, a film containing silicon is "sprayed" on to
the surface that is to become a solar panel.
Although these processes have been around for a while, the modern variations of
the thin film manufacturing process are relatively new technology, so I would argue that a
modern thin film solar PV panel's 20 year performance can only be estimated.
The production processes are generally more energy efficient than any of the other
solar PV panel types, so they take less energy to manufacture than the mono or poly
crystalline panels for the same rated power.

7. 7
Thin Film Solar Panel Efficiency
Although it is improving, thin film solar panels are typically 8-10% efficient. This
means they are around twice the size of mono or polycrystalline for the same power, and
much heavier, so you need a big, strong roof and big, strong installers!
Another thing to be aware of is that thin film solar panels can degrade by up
to 20% in the first year on your roof before settling down to their specified power
output.
You can usually spot thin film solar panels because don't have the matrix pattern of
the crystalline panels, they are just one uniform colour, usually blue, black or brown. The
other thing that gives them away is that the arrays are usually huge to make up for their low
efficiency.
Here's a roof near me that has a 2 solar arrays on it. Thin film on the left and
monocrystalline on the right. The thin film array only produces about 20% more than the
mono array despite being about 300% larger!
1.2 : Components in a Solar Power System
A complete home solar electric system requires components to produce electricity,
convert power into alternating current that can be used by home appliances, store excess
electricity and maintain safety.
1.2.1 : Solar Panels
Solar panels are the most noticeable component of a residential solar electric
system. The solar panels are installed outside the home, typically on the roof and convert
sunlight into electricity.
.)

8. 8
The photovoltaic effect is the process of converting sunlight into electricity. This
process gives solar panels their alternate name, PV panels.
1.2.2: Solar Array Mounting Racks
Solar panels are joined into arrays and commonly mounted in one of three ways: on
roofs; on poles in free standing arrays; or directly on the ground.
Roof mounted systems are the most common and may be required by zoning
ordinances. This approach is aesthetic and efficient. The main drawback of roof mounting
is maintenance. For high roofs, clearing snow or repairing the systems can be an issue.
Panels do not usually require much maintenance, however.
Free standing, pole mounted arrays can be set at height that makes maintenance
easy. The advantage of easy maintenance must be weighed against the additional space
required for the arrays.
Ground systems are low and simple, but cannot be used in areas with regular
accumulations of snow. Space is also a consideration with these array mounts.
1.2.3 : Array DC Disconnect
The Array DC disconnect is used to disconnect the solar arrays from the home for
maintenance. It is called a DC disconnect because the solar arrays produce DC (direct
current) power.
1.2.4 : Inverter
Solar panels and batteries produce DC (direct current) power. Standard home
appliances use AC (alternating current). An inverter converts the DC power produced by
the solar panels and batteries to the AC power required by appliances.

9. 9
1.2.5 : Battery Pack
Solar power systems produce electricity during the daytime, when the sun is shining.
Your home demands electricity at night and on cloudy days – when the sun isn’t shining.
To offset this mismatch, batteries can be added to the system.
1.2.6 : Power Meter, Utility Meter, Kilowatt Meter
For systems that maintain a tie to the utility grid, the power meter measures the
amount of power used from the grid. In systems designed to sell power the utility, the power
meter also measures the amount of power the solar system sends to the grid.
1.2.7 : Backup Generator
For systems that are not tied to the utility grid, a backup generator is used to provide
power during periods of low system output due to poor weather or high household demand.
Homeowners concerned with the environmental impact of generators can install a generator
that runs on alternative fuel such as biodiesel, rather than gasoline.
1.2.8 : Breaker Panel, AC Panel, Circuit Breaker Panel
The breaker panel is where the power source is joined to the electrical circuits in
your home. A circuit is a continuous route of connected wire that joins together outlets and
lights in the electric system.
For each circuit there is a circuit breaker. Circuit breakers prevent the appliances on
a circuit from drawing too much electricity and causing a fire hazard. When the appliances
on a circuit demand too much electricity, the circuit breaker will switch off or trip,
interrupting the flow of electricity.

10. 10
1.2.9 : Charge Controller
The charge controller – also known as charge regulator – maintains the proper
charging voltage for system batteries.
Batteries can be overcharged, if fed continuous voltage. The charge controller
regulates the voltage, preventing overcharging and allowing charging when required. Not
all systems have batteries
1.3 : Efficiencies of Different Solar Panels
Solar panels are usually able to process 15% to 22% of the sun power into usable
energy, depending on factors like placement, orientation, weather conditions, and similar.
The amount of sunlight that solar panel systems are able to convert into actual electricity is
called performance, and the outcome determines the solar panel efficiency.
To determine solar panel efficiency, panels are tested at Standard Test Conditions
(STC). STC specifies a temperature of 25°C and an irradiance of 1,000 W/m2
. This is the
equivalent of a sunny day with the incident light hitting a sun-facing 37°-tilted surface.
Under these test conditions, a solar panel efficiency of 15% with a 1 m2
surface area would
produce 150W.
1.3.1 : Monocrystalline Solar Panels
Monocrystalline solar panels, also called single-crystalline cells are manufactured
from the purest silicon. A crystal of this type of silicon is grown in a complex process to
produce a long rod. The rod is then cut into wafers that will make the solar cells.
Monocrystalline solar panels are known to deliver the highest efficiency in standard test
conditions when compared to the other 2 types of solar cells. The current delivered
monocrystalline solar panel efficiency stands at 22-27%. You can recognize a
monocrystalline panel by the rounded edge and the dark colour.

11. 11
Table 1.1 : Efficiencies of Different Solar Panel Technologies
1.3.2 : Polycrystalline Solar Panels
Solar panels made of polycrystalline solar panels, also called multi crystalline
cells are slightly less efficient than those made up of monocrystalline solar cells. This is
due to the nature of production. The silicon is not grown as a single cell but as a block of
crystals. These blocks are then cut into wafers to produce individual solar cells. The current
delivered polycrystalline solar panel efficiency stands at 15-22%.You can recognize a
polycrystalline solar panel by the square cut and blue speckled colour.
1.3.3 : Thin Film Solar Panels
Thin film solar panels are made by covering a substrate of glass, plastic or metal
with one or more thin-layers of photovoltaic material. Thin film solar panels are usually
flexible and low in weight. It is known that thin film solar panels degrade somewhat faster
than mono and polycrystalline solar panels. Production of this kind of panels is less
complex, thus their output is 5% less than monocrystalline solar panel efficiency. Normally,
thin film cells deliver between 15-22% solar panel efficiency.
Thin film solar panel technology is closing the efficiency gap with more expensive
types of solar panels, therefore thin film solar panels are installed on large scale projects
and in record breaking solar power plants.

12. 12
SECTION 02
THE AVERAGE CONSUMPTION OF ELECTRICITY IN
DCPE BUILDING AREA

13. 13
02. Examining the average monthly consumption of electricity within
the DCPE building area
Monthly bill records obtained from Maintenance Section of the university are
attached in the next page.
• In this project we must calculate the energy consumption of the Department of
Chemical & Process Engineering. But there is no monthly electricity bill to
measure the usage. We got the electricity bills of “Workshop area” relevant to
2018.
• Workshop region is consisting of Department of chemical and process
Engineering, Department of mechanical engineering, Portion of the “Goda”
canteen, Old gym & JG Hall.
• We managed to find the approximate areas of the regions we want by using
“GOOGLE MAP AREA CALCULTOR” of https://www.daftlogic.com/
Map 2.1 : Green Area Showing the Workshop Region

14. 14
Image 2.1 : Bill Records of Workshop Region 2018 ( January to June )

15. 15
Image 2.2 : Bill Records of Workshop Region 2018 ( June to October )

16. 16
Map 2.2 : Green Area Showing the DCPE Area Region
Table 2.1 : The Electricity Bill Report for January-October 2018
Month Usage (kWh) Rate (Rs/kWh) Energy Charge kVA Rate (Rs/kVA) Fixed Charge (Rs) Bill Amount (Rs)
January 93974 14.55 1367321.7 387 1100 3000 1796021.7
February 77489 14.55 1127464.95 390 1100 3000 1559464.95
March 43555 14.55 633725.25 154 1100 3000 806125.25
April 55939 14.55 813912.45 419 1100 3000 1277812.45
May 102115 14.55 1485773.25 442 1100 3000 1974973.25
June 91901 14.55 1337159.55 401 1100 3000 1781259.55
July 99318 14.55 1445076.9 390 1100 3000 1877076.9
August 94019 14.55 1367976.45 391 1100 3000 1801076.45
September 95272 14.55 1386207.6 450 1100 3000 1884207.6
October 95731 14.55 1392886.05 403 1100 3000 1839186.05
Average 84931.3 14.55 1235750.415 382.7 1100 3000 1659720.415
Maximum 102115 1485773.25 450 1974973.25
Minimum 43555 633725.25 154 806125.25
Range 58560 852048 296 1168848

17. 17
Calculations :
• Total area of the “workshop region” A1 = 19254.99 m2
• Total area of the DCPE (with the garden) A2 = 4698.26 m2
So, we can calculate the monthly electricity bill of the department using following
assumptions.
1.
𝑇𝑂𝑇𝐴𝐿 𝐴𝑅𝐸𝐴 𝑂𝐹 𝐷𝐶𝑃𝐸
𝑇𝑂𝑇𝐴𝐿 𝐴𝑅𝐸𝐴 𝑂𝐹 𝑊𝑂𝑅𝐾𝑆𝐻𝑂𝑃 𝑅𝐸𝐺𝐼𝑂𝑁
=
𝑀𝑂𝑁𝑇𝐻𝐿𝑌 𝐸𝐿𝐸𝐶𝑇𝑅𝐼𝐶𝐼𝑇𝑌 𝐶𝑂𝑁𝑆𝑈𝑀𝑃𝑇𝐼𝑂𝑁 𝑂𝐹 𝐷𝐶𝑃𝐸
𝑀𝑂𝑁𝑇𝐻𝐿𝑌 𝐸𝐿𝐸𝐶𝑇𝑅𝐼𝐶𝐼𝑇𝑌 𝐶𝑂𝑁𝑆𝑈𝑀𝑃𝑇𝐼𝑂𝑁 𝑂𝐹 𝑊𝑂𝑅𝐾𝑆𝐻𝑂𝑃 𝑅𝐸𝐺𝐼𝑂𝑁
2. Electricity consumption is homogeneous throughout the whole region.
Above assumptions are valid for both kVA & kWh.
KW : ACTUAL POWER
kW is the amount of power that is converted into a useful output. kW is therefore
known as actual power or working power.
❖ To find the average usage (kWh):
Usage (kWh) = 84931.3 ×
𝐴2
𝐴1
= 84931.3×
4698.26
19254.99
= 20723.4244 kWh

18. 18
KVA : APPARENT POWER
kVA is a measure of apparent power: it tells you the total amount of power in use
in a system. In a 100% efficient system kW = kVA. However electrical systems are never
100% efficient and therefore not all the systems apparent power is being used for useful
work output.
❖ To find the average kVA:
Usage (kVA) = 382.7 ×
𝐴2
𝐴1
= 382.7 ×
4689.26
19254.99
= 93.200 kVA
Total bill =
[Usage(kWh)× Rate(Rs/kWh)]+ [kVA×Rate(Rs/kVA)] + (Fixed Charge)
❖ Total monthly bill = (20723.4244×14.55) + (93.200×1100) + 3000
= Rs. 407045.82

19. 19
SECTION 03
DATA FROM SOLAR PANEL MANUFACTURERS

20. 20
.
03. Presenting Data From Solar Energy Manufacturers Needed For
The Project
After taking 3 separate quotations from 3 of the premier Solar Power unit suppliers
in the country, we understood that getting these units installed from a separate third party
Supplier will be a costly task. Especially given the fact that the capacity we require is
nearly 100,000 kWh per month. Through research we deducted that the best option for
this kind of a requirement would be to import the parts required for the unit separately
and assemble them.
Calculations 3.1 :
❖ Average Monthly Production needed : 20723.4244 kWh per month
Assuming that sunlight is generally present for 8h a day (8 am to 4pm)
• Total Power of Energy Production needed :
20723.4244 kWh
8ℎ 𝑝𝑒𝑟 𝑑𝑎𝑦 𝑋 30 𝑑𝑎𝑦𝑠 𝑝𝑒𝑟 𝑚𝑜𝑛𝑡ℎ
= 76 kW → approximately 80 kW
It was advised by the supplier that for a country like Sri Lanka which receives
constant sunlight, buying a battery system will not be needed. Hence the only the basic
components namely,
1. Polycrystalline Solar Panels
2. Solar Inverters
were considered for Calculations.

21. 21
Calculations 3.2 :
❖ Average power needed : 80 kW
❖ Single Solar Panel
o Capacity : 325 W
o General Lifespan : 30 yrs.
❖ Inverter
o Conversion Capacity : 10 kW
o General Lifespan : 15 yrs.
Assuming 100% efficiency in panels under ideal conditions
• Total number of such panels needed :
80 000 W
325 𝑊 𝑝𝑒𝑟 𝑝𝑎𝑛𝑒𝑙
= 246 → 250 panels
Assuming 100% conversion efficiency in inverters under ideal conditions
• Total number of such inverters needed :
80 kW
10 𝑘𝑊 𝑝𝑒𝑟 𝑖𝑛𝑣𝑒𝑟𝑡𝑒𝑟
= 8 inverters

22. 22
Major part of the total cost will cover the capital cost for the Power Inverters and
Solar Panel Cells. For the usage that’s required for DCPE at University of Moratuwa, is
approximately 8 inverters and 250 Cells.
Following are the CIF values(Cost Insurance Freight values) for importing the
main components of the Solar Power Generating unit.
Image 3.1 : Pricing information sent by the importing supplier (20/12/2018)
Image 3.2 : Quotation sent by the importing supplier (20/12/2018)
(1 USD = 181 LKR)
GOODWE TECHNOLOGIES (www.goodwe.com)
INVOICE (12/20/2018)
Description Quantity Unit Price (USD) Unity Price (Rs.) Cost (Rs.)
GoodWe hybrid inverter - 3 phase with ongrid/offgrid 250 91 16471 4117750
Canadian Solar Polycrystaline cell 8 3200 579200 4633600
Total 8751350
Expenses when setting up (5%) 437567.5
Inverter Warranty renewal after 5 years ( 5% per year cost) 2 875135
Total Cost 10064053
The prices may change with foreign exchange rates.

23. 23
Calculations 3.3 :
• Calculating the Principal Cost (Rs.) = 4117750 + 4633600 + 437567.50
= 9188917.50
• For each 5 yrs. inverter warranty renewal cost must be born (Rs.)
= 437567.50
For basis of 14 yrs. (Inverter lifespan is 15 yrs.) assuming no price changes,
Total cost for 14 yrs. (Rs.) = 9 188 917.50 + (437 567.50 X 2)
= 10 064 052.50

24. 24
SECTION 04
MAXIMUM FEASIBLE AMOUNT OF ENERGY THAT CAN
BE PRODUCED WITHIN THE DCPE BUILDING AREA

25. 25
04. Calculating Maximum Feasible Amount of Energy That Can Be
Produced Within the DCPE Building Area
The aim of this section is to calculate the amount of energy possible to be produced
within the DCPE building area based on the roof surface areas. DCPE has three roof
regions and a central open area. The surface areas (in sq. meters) of each area are as
follows,
1. Main Building Roof : 1025 m²
2. Laboratory Area 01 : 450 m²

26. 26
3. Laboratory Area 02 : 650 m²
(The inclinations of the walls have been neglected)
In order to calculate the possible energy generation,
• Surface Area of a Panel : 1 X 2 m²
• Possible Power generation : 325 W
• Power generation possible per sq. meter : 162.5 W/m²
Possible Amount of Energy generation from each section are as below,
No. of years after
setting the panels
Cumulative
Cost of
Average
Consumption
(Rs.)
Principal and
Cumulative Warranty
Cost(Rs.)
0 0 9188917.5
1 4884549.84 9188917.5
2 9769099.68 9188917.5
3 14653649.52 9188917.5
❖ Maximum Possible Energy Generation is 345 kW

27. 27
SECTION 05
PREDICTING THE FEASIBILITY OF THE PROJECT

28. 28
05. Predicting the Feasibility of The Project
❖ The Power generation rate needed : 80 kW
❖ The possible total power generation rate based on area : 345 kW
Hence considering the roof area wise the project is feasible. Only using the roof of
DCPE main building to set panels is sufficient.
Profitability of the Idea
No. of years after setting the panels Cumulative Cos
(Rs.)
0 0
1 4884549.84
2 9769099.68
3 14653649.52
4 19538199.36
5 24422749.2
6 29307299.04
7 34191848.88
8 39076398.72
No. of years after setting the panels Cumulative Cost of Average Consumption (Rs.)Principal and Cumulative Warranty Cost(Rs.)
0 0 9188917.5
1 4884549.84 9188917.5
2 9769099.68 9188917.5
3 14653649.52 9188917.5
4 19538199.36 9188917.5
5 24422749.2 9626485
6 29307299.04 9626485
7 34191848.88 9626485
8 39076398.72 9626485
9 43960948.56 9626485
10 48845498.4 10064052.5
11 53730048.24 10064052.5
12 58614598.08 10064052.5
13 63499147.92 10064052.5
14 68383697.76 10064052.5

29. 29
Graph 5.1 : Variation of Costs with time
❖ It is clear that within nearly two years of time, the project becomes profitable
❖ Amount of money saved at the end of 14 years,
= 68383697.76 - 10064052.50
= Rs. 58 319 645 → 58 millions
0
10000000
20000000
30000000
40000000
50000000
60000000
70000000
80000000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Costs vs Time (for 14 years)
Cumulative Cost of Average Consumption (Rs.)
Principal and Cumulative Warranty Cost(Rs.)

30. 30
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December 28, 2018, from https://www.homepower.com/articles/solar-
electricity/equipment-products/ask-experts-inverter-longevity
3. Components of A Residential Solar Electric System | Cleanenergyauthority.com.
(n.d.). Retrieved December 28, 2018, from
https://www.cleanenergyauthority.com/solar-energy-resources/components-of-a-
residential-solar-electric-system
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https://www.daftlogic.com/projects-google-maps-area-calculator-tool.html
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through-inverter-sizing/
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