Solar Refrigeration System

Senior Design Project Report
EEE/ETE 499
SOLAR BASED REFRIGERATOR SYSTEM
Submitted By
132 1076 045 – K.B. Riaz Ahmed Alif
131 1242 643 – Mohammad Muhiuzzaman
131 0585 643 – Orindom Khalid Chowdhury
Supervisor
Md Rezaul Islam – IMR
Senior Lecturer
ELECTRICAL AND COMPUTER ENGINEERING
NORTH SOUTH UNIVERSITY
SPRING 2017

Agreement Form
We take great pleasure in submitting our senior design project report on “Solar Based
Refrigerator System”. This report is prepared as a requirement of the Capstone Design Project
CSE/EEE/ETE 499 A & B which is a two semester long senior design course. This course
involves multidisciplinary teams of students who build and test custom designed systems,
components or engineering processes. We would like to request you to accept this report as a
partial fulfillment of Bachelor of Science degree under Electrical and Computer Engineering
Department of North South University.
Declared By:
………………………………………………
Name: K.B. Riaz Ahmed Alif
ID: 132 1076 045
………………………………………………
Name: Mohammad Muhiuzzam
ID: 131 1242 643
………………………………………………
Name: Orindom Khalid Chowdhury
ID: 131 0585 643
Approved By:
……………………………
Supervisor
Mohammad Rezaul Islam
Senior Lecturer, Department of Electrical and Computer Engineering
North South University, Dhaka, Bangladesh
.......................................
Dr. Rezaul Bari
Chairman, Department of Electrical and Computer Engineering
North South University, Dhaka, Bangladesh

SOLAR BASED REFRIGERATOR SYSTEM
ABSTRACT
The requirement for basic health improvements in the developing countries can be greatly
assisted by the use of cool storage for vaccines and perishable goods. There is an increasing
requirement for refrigerators in rural areas, as there is insufficient power from power grid.
This project is to develop technology which optimizes and reduces the energy requirements.
With this system the overall cost/performance ratio of a solar powered refrigerator can not only
reduce but can also be beneficially used in high specification conventionally powered
refrigerators in rural areas.

Table of Contents
Chapter 1: Introduction
1.1 Project Details 1
1.2 Background and Motivation 2
1.3 Project Goal 2
Chapter 2: Technical Details
2.1 Market Research 4
2.2 Existing Solution 4
2.3 Proposed Solution 4
2.4 Solution Assessment 5
2.5 Technical Design: System Level 6
2.6 Technical Design: Module Level 7
2.7 Required Skill 8
Chapter 3: Essential parts and Devices
3.1 Description of Components 10
3.2 Test Equipments 23
Chapter 4: Working Sheets
4.1 Work Breakdown Structure 28
4.2 Financial Plan and Costs 30
Chapter 5: Project Summary
5.1 Result and Discussion 32
5.2 Feasibility Study 36
5.3 Problem Faced and Solutions 37
5.4 Future Development 37
5.5 Conclusion 37
5.6 Project Demonstration Review 38
5.7 Brochure 39
5.8 Poster 39
5.9 IEEE format paper
Appendix
A Reference 40
B Codes 41

List of Figures:
Fig No Name Page
1 Temperature vs Time graph (1) 5
2 Temperature vs Time graph (2) 5
3 Power vs Time Graph over 24hr Period 6
4 Proposed Block Diagram for the refrigerator 7
5 Components of Compression Refrigeration 8
6 Mono 100Watt Solar panel 10
7 Phocos Solar charge Controller 11
8 Circuit diagram of Solar Charge Controller 12
9 Lithium Ion battery mechanisms 13
10 12 V, 40 Ah Solar Rechargeable Battery 14
11 600VA Inverter [Front Side] 15
12 600VA Inverter [Back Side] 16
13 Meiling-Ston RV40 Refrigerator [Front Side] 17
14 Meiling-Ston RV40 Refrigerator [Back Side] 18
15 Circuit Diagram of the Refrigerator 18
16 Current Sensor 19
17 Voltage Sensor 20
CHAPTER 1

1
1.1 Project Detail
Bangladesh is a country where very few amount of people actually use the electricity.
Without the electricity it is very difficult for most of the people to maintain their day to
day life. One of the main concerns for the village people is food. To store food and
cooling purposes we use refrigerator. Because of the lack of electricity most of the
people can’t use this. For a friendly and feasible use of the refrigerator this project
describes a solar based refrigerator where detail study of the voltage current and
temperature is provided in real time via data logger.
The system is made up with a solar panel consists of 12V and 100 Watt. The maximum
Power of the panel is (Pmax) 100V, Rated output voltage is (Vmp) 17.5V and Rated
current is (Imp) 5.72Amp. A charge controller, 12 Volt battery, 500 Watt inverter,
refrigerator, data logger and some LEDS are also used. It is assumed that sun will be
available for 10 hours in summer days.
In this Project, Solar panel is used for powering the system which provides DC power.
A battery is used to store the charge of the solar panel. In between the solar panel and
battery a charge controller is used to regulate the voltage output from the solar panel
and prevent battery from being overcharged and overheated. As most of the home
appliances use AC power for its operation the DC power from the battery need to be
converted into AC and for that an sin waved inverter is used. This AC power is then
used to power up the refrigerator. A data logger is used which will provide the data of
the current, voltage and temperature in real time. This data logger is actually made up
with Arduino UNO, Voltage Sensor, Current Sensor and temperature sensor. It
connected in between the solar panel and battery. The system is such that whenever the
battery charge is under 30% and the refrigerator temperature is above 50
C, the
compressor of the refrigerator will not Turn ON. This control system is controlled by
the Arduino UNO. It is nothing, but many of us don’t know that when a DC Battery
charge goes under 30% and uses that, it gradually decreases the Battery life even
sometimes stop taking charge the battery.

2
1.2 Background and Motivation:
The average temperature of Bangladesh in summer ranges form 30-40 degree Celsius.
And most part of Bangladesh people are unable to prevent rotting food. Storage is also a
problem. People from the rural part use a communal to store their food and necessary
things. In the modern era where internet is considered a normal right we need to come
up with better solution with normal household products. Things like refrigerator,
electricity, television and other things should be cheap and available considering the
modern culture. And with this solar powered refrigerator we can make one giant step
towards the lifestyle of thousands of people. We can create a world where cold water,
preventing food from being rotted won’t be considered a privilege or an expensive
thing.
1.3 Project goal
The main goal of this project is to provide a design for the feasible use of the
refrigerator. The information can be available in market that which solar panel, battery,
inverter should use, but our goal is not using Big battery, inverter or the panel. By
collecting data we are able to make a way how people can use the exact power amount
of equipment. The main idea is to combine the solar home system. One of the main
concern of this project deals with the power consumption. This proposed design can
also be used for different electrical home appliances.
The main goal of this project is to:
Power Optimization.
A low cost system for people of rural areas.
Control of compressor with Arduino.
Make the system efficient and environment friendly.
Compact design
Propose in large scale production

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2.1 Market Research
There is no commercial solar based refrigerator available in Bangladesh. We tend to
make it commercial. The fridge available on market tends to consume a huge energy.
Recently NASA is searching for a well and feasible solar based refrigerator for MARS
and International Space Program. Innovators at NASA's Johnson Space Center have
patented a proven, solar-powered refrigeration system that eliminates reliance on an
electric grid, requires no batteries, and stores thermal energy for efficient use when
sunlight is absent. The innovation uses a variable speed, direct current (DC) vapor
compression cooling system, connected to a solar photovoltaic (PV) panel via novel
electronic controls. This environmentally friendly system is ideal for use in commercial
or household refrigerators, freezers, vaccine coolers, or solar ice-makers. It is
particularly ideal for off-grid applications.
2.2 Existing Solution
The Existing solution for the refrigerator in rural areas is actually a solar home system
(SHS). There are actually so many project based on solar power. One of the existing
solution is a solar energy semiconductor cooling box. The cooling box is compact and
easy to carry, can be made a special refrigeration unit which is smaller according to user
needs. The characteristics of the cooling box are its simple use and maintenance, safe
performance, decentralized power supply, convenient energy storage, no environmental
pollution, and so on [1]. Another existing system which concludes solar refrigeration
system as Solar Electric Method, Solar Mechanical Method and Solar Thermal Method
which covers both refrigerator, Cooling Thermal Energy Storage (CTES) and Chilled
Water Storage (CWS) [2].
2.3 Proposed Solution
The proposed solution is to create a solar based Refrigerators which will be enough
efficient to work in those area where no or less electricity available. And for urban
population it will be cheap, effective and green. In the era of global warming a little
dent in this situation is tried to make. But this small change can bring enough to make it
worthwhile. The system is made such that Refrigerator run for 12Hr without sun
energy.

5
2.4 Solution assessment
The main goal is to create a green and less electricity fridge. So, a 75W fridge
connected with a 12V solar panel is used. To control it properly a 500W inverter
connected with a 12V battery has been used. So in the calculation it will run like 12
hour. Two graphs of Temperature vs. Time graph of a refrigerator in a day is given
below along with a power vs. temperature graph
Fig 1: Temperature vs Time graph (1)
Fig 2: Temperature vs Time graph (2)

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Fig 3 : Power vs Time Graph over 24hr Period
2.5 Technical Design: Module Level
The Proposed system is nothing but a solar home system combining a data logger. The
operation of data logger differentiate the system from the existing solar home system.
The block diagram in Fig 2.5 represents the system level design of the proposed project.
In this block diagram a solar panel, charge controller, battery, inverter, refrigerator and
a data logger is used.

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Fig 4 : Proposed Block Diagram for the refrigerator
From Fig 4 it can be seen that the refrigerator is connected with an inverter as it has to
be run in AC power. This inverter is connected with a 12 V battery which holds the
charge of the solar panel. The inverter converts the DC power of the battery into AC.
The solar panel is of 100 W. In between the Solar panel and Battery a 20AH charge
controller is connected which prevents the battery from overcharge. A data logger is
connected in between the panel and Battery. It displays the voltage, current and
temperature reading via arduino uno. A temperature sensor is used to sense the
temperature of the freeze. Another arduino uno is placed with the refrigerator where
some LEDs are connected. This LEDs are used to show the charge state of the Battery
to the users. When the charge state of the Battery is 100% a green LED is on. When the
charge state is at 60% a blue LED is on. 40% charge state is an alarming condition and
for this charge condition a yellow LED is on.
2.6 Technical Design: System Level
The compressor constricts the refrigerant vapor, raising its pressure, and pushes it into
the coils on the outside of the refrigerator. When the hot gas in the coils meets the
cooler air temperature of the kitchen, it becomes a liquid.Now in liquid form at high
pressure, the refrigerant cools down as it flows into the coils inside the freezer and the
fridge. The refrigerant absorbs the heat inside the fridge, cooling down the air.Last, the
refrigerant evaporates to a gas, then flows back to the compressor, where the cycle
starts all over.Of the reciprocating, rotary, and centrifugal compressors, the most
popular among domestic or smaller power commercial refrigeration is the reciprocating.
The reciprocating compressor is similar to an automobile engine. A piston is driven by

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a motor to "suck in" and compress the refrigerant in a cylinder. As the piston moves
down into the cylinder (increasing the volume of the cylinder), it "sucks" the refrigerant
from the evaporator. The intake valve closes when the refrigerant pressure inside the
cylinder reaches that of the pressure in the evaporator. When the piston hits the point of
maximum downward displacement, it compresses the refrigerant on the upstroke. The
refrigerant is pushed through the exhaust valve into the condenser. Both the intake and
exhaust valves are designed so that the flow of the refrigerant only travels in one direct
it through the system.
Fig 5: Components of Compression Refrigeration
2.7 Required Skill
Anyone can actually use the proposed project for their day to day purpose. But to build
the system some engineering skills are required. It is important to know the basic use of
solar technology. Maintenance of the battery is required in the long run. After
converting the DC power into AC the inverter contains a huge amount of power. So it
should not be touched with an open hand. The LEDs are provided to alarm users about
the charge state. In this project we needed to learn the Arduino Coding and revising
some basic concept of our Engineering topics.

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CHAPTER 3
ESSENTIAL PARTS AND DEVICES

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3.1 Description of Components
Here is short descriptions of the required Components/Tools/ Software for designing
the device with picture.
 Solar Panel
A solar cell, or photovoltaic cell, is a semiconductor device consisting of a large-area p-
n junction diode, which in the presence of sunlight is capable of generating usable
electrical energy. This conversion is called the photovoltaic effect, which commonly
shortened to PV.
Crystalline silicon and gallium arsenide are typical choices of materials for solar cells.
Gallium arsenide crystals are grown especially for photovoltaic use, but silicon crystals
are available in less-expensive standard ingots, which are produced mainly for
consumption in the microelectronic industry. Polycrystalline silicon has lower
conversion efficiency but also lower cost where monocrystalline being more cost
produces a greater output compared to polycrystalline [3].
In this project a 100 Watt Solar panel is used which has power tolerance of +10/-5% &
are backed by 10/25 year power warranty. Fig 6 shows the solar panel which has been
used in this project. [4]
Fig 6: Mono 100Watt Solar panel

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 Charge Controller
A charge controller, or charge regulator is basically a voltage and/or current regulator to
keep batteries from overcharging and overheating. It regulates the voltage and current
coming from the solar panels going to the battery. Most "12 volt" panels output voltage
is about 16 to 20 volts. So if there is no regulation the battery will be damaged from
overcharging. Most batteries need around 14 to 14.5 volts and 4-5 Amps to get fully
charged.
In this project we used “Phocos CA06-2.2 12V Solar Charge Controller”. The Phocos
CA solar charge controller series is especially designed for small solar systems with the
need of a low battery disconnect feature. The regulation circuit provides regulation to
prevent single cell overheat problems of short-circuited solar panels. The terminal
section has been replaced by a rugged, well profen 16mm2
terminal block. The melting
fuse of the predecessor has been replaced by a fully electronically protected circuit.
2×LEDs and 1×Duo-LED to display charging in progress, battery SOC, load disconnect
and overload status. Leisure and rural electrification systems are the typical applications
for this product. It is a perfect solution for cost-sensitive systems which require state of
the art system managemen
 Electronically regulated charging regime: Boost and float charge
 Deep discharge protection
 PWM series regulation, no panel short circuit.
 Integrated temperature compensation
 Fully electronically protected: Panel surge voltage, wrong polarity at panel or
battery, Overload and short circuit at load
 3 LED indications: Charge status, SOC, LVD, Overload! Short Circuit
 Common positive grounding.
Fig 7: Phocos Solar charge Controller

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Fig 8: Circuit diagram of Solar Charge Controller
The most common controls used for all battery based systems are in the 4 to 60 amp
range, but some of the new MPPT controls such as the Outback Power FlexMax go up
to 80 amps [5].
 Battery
An electric battery is a device consisting of one or more electro-chemical cells with
external connections provided to power electrical devices. In this thesis, we use battery
for constant voltage and current supply because our main ambition to control the
voltage and current and kept it constant. Lifespan of the battery depends on charging
and discharging. The charging capacity of the battery measured with Amp‐hour. Battery
ratings are depended according to cycle. In vehicle there is used shallow cycle battery
which implies battery have cycles between 10% ‐ 15% of batteries total capacity. There
are different types of batteries in the market but lead acid batteries mainly used to store
energy [6].
The battery that has been used in this project is a lead acid battery of 12V and 40AH.
It’s a Japanese brand called Morita and they are distributed by Japan Solar-tech
(Bangladesh) Limited. There are two types of batteries available which are primary and
secondary. In this project a Lithium Ion battery has been used. It is described below.

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A lithium-ion battery (Li-ion battery or LIB) is a rechargeable battery. Lithium-ion
batteries are turning into a typical swap for the lead acid batteries that have been used
for golf carts and utility vehicles. Lithium-ion batteries are common in home
electronics. They are one of the most popular types of rechargeable batteries for
portable electronics, with a high energy density, tiny memory effectand low self-
discharge. Beyond consumer electronics, LIBs are also growing in popularity for
military Lithium-ion can give the same voltage as lead-acid batteries. Lithium-ion
batteries include short cycle lives (hundreds to a few thousand charge cycles) and
significant degradation with age. Most other EVs are utilizing new variations on
lithium-ion chemistry that sacrifice energy and power density to provide fire resistance,
environmental friendliness, extremely fast charges (as low as a few minutes), and very
long lifespan [7].
Figure 9: Lithium Ion battery mechanisms

14
Fig 10: 12 V/40Ah Solar Rechargeable Battery
 Inverter
An inverter is an electronic device or circuitry that changesdirect current (DC) to
alternating current (AC). The input voltage, output voltage and frequency, and overall
power handling depend on the design of the specific device or circuitry. The inverter
does not produce any power; the power is provided by the DC source. Voltage Source
Inverters are devices that convert a DC voltage to AC voltage of variable frequency and
magnitude. They are very commonly used in adjustable speed drives and are
characterized by a well-defined switched voltage wave form in the terminals. The AC
voltage frequency can be variable or constant depending on the application. Three
phase inverters consist of six power switches connected to a DC voltage source. The
inverter switches must be carefully selected based on the requirements of operation,
ratings and the application [7].

15
In this project we used a sinusoidal Inverter, which takes input of 12V DC and gives
output of 215-220V as AC. The advantage of our inverter is, it can even directly run by
the solar panel. But it is not secure, because the sun is not constant all the time. So The
safe way is to used by a battery.
Fig 11: 600VA Inverter [Front Side]

16
Fig 12: 600VA Inverter [Back Side]

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 Refrigerator
A refrigerator (colloquially fridge) is a popular household appliance that consists of a
thermally insulated compartment and a heat pump (mechanical, electronic or chemical)
that transfers heat from the inside of the fridge to its external environment so that the
inside of the fridge is cooled to a temperature below the ambient temperature of the
room. Refrigeration is an essential food storage technique in developed countries. The
lower temperature lowers the reproduction rate of bacteria, so the refrigerator reduces
the rate of spoilage. A refrigerator maintains a temperature a few degrees above the
freezing point of water. Optimum temperature range for perishable food storage is 3 to
5 °C (37 to 41 °F) [8]. A similar device that maintains a temperature below the freezing
point of water is called a freezer. The refrigerator replaced the icebox, which had been a
common household appliance for almost a century and a half. For this reason, a
refrigerator is sometimes referred to as an icebox in American usage. Here is in this
project a 50WW refrigerator has been used.
Fig 13: Meiling-Ston RV40 Refrigerator [Front Side]

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Fig 14: Meiling-Ston RV40 Refrigerator [Back Side]
Fig 15: Circuit Diagram of the Refrigerator

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 Data Logger
A data logger, is an electronic instrument that records measurements at set intervals
over a period of time. Depending on the particular data logger, measurements can
include: air temperature, relative humidity, AC/DC current and voltage, differential
pressure, time-of-use (lights, motors, etc.), light intensity, water temperature, water
level, dissolved oxygen, soil moisture, rainfall, wind speed and direction, leaf wetness,
pulse signals, room occupancy, plug load, and many more.
Data logger is typically an Arduino based device equipped with Voltage sensor, Current
Sensor, Temperature sensor and SD card module. In this project two voltage sensors,
two current sensors and a temperature sensor was used. The Voltage sensor can sense
upto 25V and the current Sensor upto 30A. The temperature sensor is waterproof. So
while using it in the refrigerator, if it gets wet that won’t make any problem. Some
equipment description of the Data logger is given bellow.
Current Sensor
This is a breakout board for the fully integrated Hall Effect based linear ACS712(30A)
current sensor. The sensor gives precise current measurement for both AC and DC
signals. The ACS712 outputs an analog voltage output signal that varies linearly with
sensed current. The device requires 5VDC for VCC.
 30Amp Range with a chip of ACS712 Current Sensor Module for Arduino
 Pin 5V power supply, on-board power indicator
 The module can measure the positive and negative 30A, corresponding to the
analog output 100mV/A
 There is no the detection current through, the output voltage is VCC/2
Fig 16: Current Sensor

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Voltage Sensor
This module is based on a resistive divider design principles, it will reduce the voltage
of the input terminal connection by five times, Arduino analog input voltage up to 5V,
thefore the input voltage of the voltage detection module cannot be greater than 5V × 5
= 25V ( If 3.3V system used, the input voltage does not exceed 3.3Vx5 = 16.5V).
Arduino AVR chips use 10bit AD, so the simulation resolution of this module is
0.00489V (5V / 1023), so the voltage detection module detects minimum input voltage
is 0.00489V × 5 = 0.02445V.
 Input voltage range: DC (0 - 25V)
 Voltage detection range: DC (0.02445V - 25V)
 Voltage analog resolutions: 0.00489V
 DC Input: positive terminal connect to VCC, negative terminal to GND
Fig 17: Voltage Sensor
Temperature Sensor
The Temperature Sensor has a waterproof probe and long wire shape, suitable for
immersive temperature detection. The chip inside this sensor is DS18B20 which is
widely adopted. It is required to add an extra resistance to get it working. So for this
sensor, we adjusted it into a Grove port and had a resistance pre-assembled inside so
that we can use it as a regular Grove sensor. This makes it an easy connected one wire
temperature senor for Seeeduino，which is derived from Arduino and compatible with
all Arduino platforms.
Caution
The cable part cannot be put under temperature higher than 70°C for a long time.

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 Requires only one wire for data interface.
 Waterproof
 Accepts 3.0V - 5.5V power Supply
 Wide temperature range: -55°Cto +125°C
 High accuracy: ±0.5°C( -10°C to +85°C)
Fig 18: Temperature Sensor
SD Card Module
SD Card Module is a breakout board used for SD card processes such as reading and
writing with a microcontroller. The board is compatible with microcontroller systems
like Arduino. A standard SD card can be directly inserted into the board, but to use
microSD cards, you need to use an adapter.
SD Card Module can be used in any project that requires data reding and writing. The
board has built in 3.3V voltage regulator.
 SD Card Module
 Standard SD card reading/writing
 MicroSD cards can be inserted using an adapter
 Built-in 3.3V voltage regulator
Fig 19: SD Card Module

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Fig 20: Data Logger.
3.2 Test Equipments
To test our complete project we first set the solar panel in rooftop. Then the VCC and
GND wires connected with the solar charge controller. After that two wires connected
with the Battery to charge up. The Inverter is always connected with Battery as the input
power source. Behind the inverter there is a place to connect the AC Loads. So there we
connected the Refrigerator input wires and turned ON the inverter. Connecting
everything with wires is easy, but the real challenge is if we connect everything correctly
but it explodes, then there is a problem. For that reason at first we checked the battery is
fully charged or not. So, at the beginning we charged the battery with solar panel. It took
around 5hrs to fully charge. After that the inverter turned ON and the refrigerator is
running normally. The main concept of our project was to run a refrigerator at night and
without any electricity. So we succeed in our concept.

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Initially a Digital Multimeter is used to measure the voltage and current of the Panel and
Battery. But at the second stage of our project we made the Datalogger and started to
collect the voltage and current of solar panel and Battery. We added a Temperature
sensor for sensing the temperature and as mention earlier if the battery level in under
30% and the temperature is 50
C + then the compressor will not turn ON if required.
We took some real values of Voltage, Current and Temperature for feasibility test. After
that we made some average graph of 24hrswhich is given in the chapter 5.
A sample view of Datalogger output is given below:
V1= Solar panel voltage V2= Battery voltage
A1= Battery current A2= Solar current T= Fridge temp
Welcome to datalogger
Time, V1, V2, A1, A2 T
12.00 13.27, 13.15, 0.07, 1.67, 9.81
13.00 12.98, 12.85, 0.15, 2.44, 4.82
14.00 12.95, 12.83, 0.07, 0.44, 3.98
15.00 12.95, 12.85, 0.07, 0.54, 2.54
16.00 12.90, 12.85, 0.07, 0.35, 3.54
17.00 12.80, 12.85, 0.07, 1.65, 2.97
18.00 12.10, 12.83, 0.07, 2.33, 1.21
19.00 11.43, 12.81, 0.07, 0.41, 0.98
20.00 08.97, 12.50, 0.07, 0.44, 1.54
21.00 08.94, 12.02, 4.00, 0.43, 1.76
22.00 07.98, 11.73, 0.15, 0.42, 0.99
23.00 08.10, 11.01, 4.66, 0.45, 0.56
00.00 08.15, 10.60, 2.07, 0.47, 0.89
01.00 07.99, 10.63, 1.78, 0.49, 1.03
02.00 08.22, 10.59, 1.92, 0.52, 1.98
03.00 08.31, 10.61, 2.89, 0.43, 2.54
04.00 08.33, 10.54, 0.15, 0.40, 3.22
05.00 09.51, 10.50, 0.15, 0.42, 3.98
06.00 10.12, 10.79, 1.55, 0.43, 4.54
07.00 10.87, 11.02, 0.22, 0.41, 2.32
08.00 11.76, 11.65, 2.59, 0.44, 1.98
09.00 12.78, 12.21, 0.15, 0.43, 1.65
10.00 12.93, 12.63, 2.59, 0.46, 4.88
11.00 13.16, 12.71, 0.15, 0.52, 0.54

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12.00 11.27, 12.17, 0.07, 1.67, 6.81
13.00 11.98, 12.84, 0.15, 2.44, 3.82
14.00 11.95, 12.51, 0.17, 0.44, 3.98
15.00 10.95, 12.82, 0.13, 0.54, 2.54
16.00 10.90, 12.65, 0.16, 0.35, 3.54
17.00 10.80, 12.76, 0.09, 1.65, 2.97
18.00 10.10, 12.67, 0.04, 2.33, 1.21
19.00 09.43, 12.78, 0.08, 0.41, 0.98
20.00 08.96, 11.10, 0.07, 0.48, 1.54
21.00 08.93, 11.01, 3.00, 0.43, 1.76
22.00 07.94, 10.76, 0.15, 0.42, 0.99
23.00 08.16, 10.10, 4.66, 0.45, 0.56
00.00 08.12, 10.23, 2.07, 0.47, 0.89
01.00 07.97, 10.15, 1.78, 0.49, 1.03
02.00 08.28, 10.32, 1.92, 0.52, 1.98
03.00 08.33, 10.21, 2.89, 0.43, 2.54
04.00 08.39, 10.23, 0.15, 0.40, 3.22
05.00 09.53, 10.50, 0.15, 0.42, 3.98
06.00 10.16, 10.79, 1.55, 0.43, 4.54
07.00 10.82, 11.05, 0.22, 0.41, 2.32
08.00 11.76, 11.62, 2.59, 0.44, 1.98
09.00 12.77, 12.24, 0.15, 0.43, 1.65
10.00 12.92, 12.62, 2.59, 0.46, 4.88
11.00 13.11, 12.76, 0.15, 0.52, 0.54

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12.00 13.24, 13.15, 1.54, 1.67, 1.81
13.00 12.95, 12.85, 0.15, 2.44, 3.82
14.00 12.43, 12.83, 0.67, 0.44, 5.98
15.00 12.76, 12.85, 0.57, 0.54, 1.54
16.00 12.87, 12.85, 0.76, 0.35, 6.54
17.00 12.65, 12.85, 0.68, 1.65, 7.97
18.00 12.43, 12.83, 0.87, 2.33, 1.21
19.00 11.67, 12.81, 0.46, 0.41, 0.98
20.00 08.87, 12.50, 0.98, 0.44, 1.54
21.00 08.84, 12.02, 4.03, 0.43, 1.76
22.00 07.88, 11.73, 0.56, 0.42, 0.99
23.00 08.30, 11.01, 4.69, 0.45, 0.56
00.00 08.45, 10.60, 2.02, 0.47, 0.89
01.00 07.29, 10.63, 1.78, 0.49, 1.03
02.00 08.42, 10.59, 1.93, 0.52, 1.98
03.00 08.51, 10.61, 2.86, 0.43, 2.54
04.00 08.33, 10.54, 1.54, 0.40, 3.22
05.00 09.21, 10.50, 0.71, 0.42, 3.98
06.00 10.42, 10.79, 1.53, 0.43, 4.54
07.00 10.37, 11.02, 1.29, 0.41, 2.32
08.00 11.56, 11.65, 2.59, 0.44, 1.98
09.00 12.88, 12.21, 0.19, 0.43, 1.65
10.00 12.93, 12.63, 2.53, 0.46, 4.88
11.00 13.16, 12.71, 0.12, 0.52, 0.54

27
4.1 Work Breakdown Structure
Here is complete breakdown of our working process throughout our course 499A and
499B
Table of work breakdown structure
Week Description
Week 1 The first class we had a basic instruction of how to precede throughout the
semester and what can be the projects we can make. And what is the sole
purpose of this course.
Week 2 We have been tasked to present an individual idea of ours to have us find
proper group members to make the idea into reality.
Week 3 The 2nd
part of idea presentation continues.
Week 4
We formed our group. And pinpointed our project for the semester. And we
had our first meeting with our faculty and we came to know about all the
necessities we need to make this project possible.
Week 5 We made our necessary calculations and showed our detail to our faculty
and we have been pointed out that we were wrong.
Week 6 We made adjustments to our calculations and had the next meeting with our
respected faculty. And we were given detail about the graph.
Week 7 We collected some graphs from internet and made all the necessary
adjustments to show our faculty.
Week 8 We made contact with local solar vendor and made adjustments with our
refrigerator as we had plans to use a small size of fridge.
Week 9 We went to Walton and other big companies for smaller fridge. And
surveyed the market.
Week 10 We made Component list and financial plans.And submitted to our
respected faculty. And approved our plan
Week 11 We went to Patuatuli and Nawabpur for the necessary components. And

28
surveyed the market.
Week 12 We went to patuatuli again and bought Solar Panel and Solar charge
controller.
Week 13 In this week we went to the market and fixed our fridge, but didn’t buy it.
Then calculated how much power we need to run that fridge. After that we
decided and bought 12V, 40Ah Battery with 600VA inverter.
Week 14 By this week we started to give charge the Battery with the Solar Panel and
tested with some Small AC elements.
Week 15 In this Week We bought the fridge and experimented that, it was working
perfectly
Week 16 It was a testing week whether, the fridge is running perfectly, and was
looking over how much time the battery gives power to the refrigerator and
observing how much time the battery was giving power to the refrigerator
for power up.
Week 17 In this week our faculty told us to take the values of voltage current and
temperature. And for that he suggested to make a datalogger to take these
values and store it in a SD card.
Week 18 By this week we managed and in a short period we made the Datalogger
with Arduino and showed it to our respected faculty.
Week 19 We started taking data of voltage, current and temperature.
Week 20 From the data we made graphs to visualize the outcome and how much time
we can use the refrigerator.
Week 21 Bought Some extra wires to make the project shorter and look better in the
capstone showcase. And were ready to give a demo to our faculty.
Week 22 We have given our final demo to our faculty.
Week 23 By this week we designed our poster for the showcase and approved by our
faculty.
Week 24 Getting ready for our capstone showcase.

29
4.2 Financial Plan and cost
As our goal is to make the cheap version of solar powered refrigerator so our overall
budget was not too much. We didn’t manage any external funding for our project as a
result we split total cost with 3 group member of this project.
Tabulated expenses
Component cost
Solar Panel 4000 tk
Solar Charge Controller 500 tk
12V/40Ah DC Battery 4000tk
600VA Sinusoidal Inverter 4500tk
50W Small Fridge 8000tk
Total 21,000 tk
Table 2: Financial plan and cost
As Datalogger was for taking the output values, so we didn’t add the cost of Datalogger.
But it costed around 2000 tk.

31
5.1 Result and Discussion
The data logger has been used to measure the current, voltage and temperature in real time. The
data logger measures the data of the battery and solar panel which are actually the DC units. By
measuring the power of the battery and solar panel for 24hrs, the effectiveness of this project can
be justified. The figures below give some data of the solar and battery power with respect to time
Fig 5.1 Time vs. Battery Power graph (1)

32
The figures above are basically twoweeks average data in 3 graphs of battery’s power. The
power has been calculated by multiplying the voltage and current of the battery. It can be seen
that the graphs are not linear it is because the condition of whole day cannot be same. In case of
sunny condition the graph lines will rise. In cloudy, gloomy, rainy, evening and night condition

33
the graph lines will fall. It is because the battery actually stores charge from the solar panel.
Based on the condition of the weather the charge capacity will vary.
The figures below shows the Time vs. Solar panel power graph of two weeks in 3 graphs
respectively.
Fig 5.4 Time vs. Solar Panel Power graph (1)

34
The above figures graph lines also vary because of the weather and day condition. Solar panels
efficiency depends on the solar radiation. In case of sunny condition maximum solar radiation
occurs. In maximum radiation the power capacity output of the panels will be higher. Thus the
graph lines will rise. Minimum solar radiation occurs when there will be cloudy, gloomy, rainy,

35
evening and night condition. In this case the graphs line will fall as the power capacity will be
less in the panels.
There might be a question arise that why the graph lines of the panels and the battery are not
same? It is because that the battery actually stores charge from the solar panels. It takes time for
the battery to discharge from the charge level. And also some time requires for charging from
discharging as our load fridge was connected as load.
5.2 Feasibility Study
Our main goal of the project is to make it as feasible as possible. We used the solar power
because it is the greenest energy available, and it’s abundant. The control of the power
was tough, but we made it as easy and possible. We used a refrigerator with no electricity
bill. We expect at least 12 hour of uninterrupted energy. The application of making it so
easy will make it easily accessible and attractive to people of all standard. And with a
commodity like refrigerator and the appeal of making it so green and cheap make it
feasible. Solar-powered refrigerators and other solar appliances are commonly used by
individuals living off-the-grid. They provide a means for keeping food safe and preserved
while avoiding a connection to utility-provided power. Solar refrigerators are also used in
cottages and camps as an alternative to absorption refrigerators, as they can be safely left
running year-round. Other uses include being used to keep medical supplies at proper
temperatures in remote locations, and being used to temporarily store game at hunting
camps.

36
5.3 Problem faced and Solutions
We initially had a plan to use a 150W refrigerator. But with a 100W solar panel we
cannot support it properly. It means, the refrigerator then would run for 3/4 hrs. For that
we searched a small fridge for the demo. To run a big fridge or big load like air-
condition, Television etc we will need a big sized batteryand a big size solar panel
depending on the load. So for the project we needed to calculate how much power we
need to run a Load for 12hrs a day without sun energy. So after theoretical calculation we
bought our components, and fortunately sometimes we got more than 12hrs support.
5.4 Future Development
The whole study could be a ground work for all the home appliances and the study of the
real time data can be used for commercial purposes. It is to be noted that this project has
been developed using a data logger that has been made with Arduino UNO. In
commercial purposes using only Arduino UNO cannot be that much effective. In
commercial purposes instead of Arduino UNO FPGAs can be used.
In future development our dream is to develop the fridge where the temperature will
remain more constant that now. And there is another wish that is, the fridge can sense the
battery level that can give power and the fridge itself reduce its temperature if the battery
level reduced then the refrigerator can keep the temperature cool for long time
automatically.
5.5 Conclusion
Though the electricity production growth of Bangladesh increasing day by day. The rural
areas are being deprived of this growth. To meet up the day to day challenges people
need electricity in some cases. Those cases include cooking, cooling storing. This project
demonstrate solar based refrigerator in which the cooling and storing problems can be
lessen up. It can also reduce the GHG emission rates as the use of the refrigerators can be
controlled. In case of refrigerator if cookers or microwaves are used it can also solve the
problem of cooking for rural people. The results found in the project justify that this
project can be effective in small scale. In small scales this project is feasible and user

37
friendly. In a country like Bangladesh where people face difficulty to use electricity this
kind of project can almost solve many day to day life problems.
5.6 Project Demonstration Review
When it comes to project demonstration review, we first want to thank our Supervisor
Mohammad Rezaul Islam sir. By the grace of Almighty and with all the support provided
by Rezaul Sir, we could complete the project within due time.
For the Demonstration day, we prepared our best to represent our project to everyone
accordingly. As it was our first time, we were little bit nervous. But in the end all went
really well. Students as in senior, junior and friends came to look at our projects which
are the results of backbreaking work of 8 months. Everyone liked our Solar Fridge, and
appreciated our drudgery. They gave many positive comments and different types of
reviews.Moreover, people from industry came to see our work and they admired our
project. The most amazing appreciation we got on that day is they wanted to work with
us and wantedto have a report of our Solar Fridge to be in the market. It would be great if
we bring this low-cost Solar Fridge in market, which can take technology to another level
in Bangladesh.

38
5.7 & 5.8 Poster and Brochure

39
REFERENCES APPENDIXA
[1] http://ieeexplore.ieee.org/document/5553992/?reload=true
[2] http://www.ijert.org/view-pdf/2354/a-review-on-solar-powered-refrigeration-and-the-
various-cooling-thermal-energy-storage-ctes-systems
[3] http://www.electro-tech-online.com/threads/solar-panels-the-theory-and-uses.94469/
[4] http://www.ensyscobd.com/solar_panel_bangladesh.html
[5] https://www.solar-electric.com/learning-center/batteries-and-charging/solar-charge-
controller-basics.html
[6] Sakib Ahmed, “Optimized Charging of Electric three Wheelers using Hybrid Energy
System” American International University – Bangladesh, Spring 2015-2016, May, 2016.
[7] Electro Schematics PWM Inverter Comments from power supply, [online: September 14th
2015], [cited: October 27,2016 ] Available :http://www.electroschematics.com/5865/pwm-
inverter/
[8] Crompton, T. R.,” Battery Reference Book” third edition, 2000-03-20. ISBN: 0080499953
[9] RC Galloway and C-H Dustmann, “Meridian International Research on Battery
Technologies” November15 2005, Available: http://www.meridian-int
res.com/Projects/Zebra_Pages.pdf
[10] Basic to Advanced Battery Information from Battery University [Online: October 20, 2010],
[Cited: October 25, 2016], Available: http: //www.batteryuniversity.com
[11] Keep your fridge-freezer clean and ice-free, BBC, 30 April 2008.
[12] Circuit diagram of Solar Charge Controller http://www.electroschematics.com/8847/3a-
6v12v-solar-charge-control/

40
CODES APPENDIXB
Arduino Code
#include <SPI.h>
#include <SD.h>
#include <Wire.h>
#include <OneWire.h>
#include <DallasTemperature.h>
// Data wire is plugged into pin 2 on the Arduino
#define ONE_WIRE_BUS 2
/********************************************************************/
// Setup a oneWire instance to communicate with any OneWire devices
// (not just Maxim/Dallas temperature ICs)
OneWire oneWire(ONE_WIRE_BUS);
/********************************************************************/
// Pass our oneWire reference to Dallas Temperature.
DallasTemperature sensors(&oneWire);
int vc1;
int vc2;
float temp;
const int analogIn1 = A2;
int mVperAmp1 = 66; // use 100 for 20A Module and 66 for 30A Module
int RawValue1= 0;
int ACSoffset1 = 2500;
double Voltage1 = 0;
double Amps1 = 0;
const int analogIn2 = A3;
int mVperAmp2 = 66; // use 100 for 20A Module and 66 for 30A Module
int RawValue2= 0;
int ACSoffset2 = 2500;
double Voltage2 = 0;
double Amps2 = 0;

41
File myFile;
void setup() {
// Open serial communications and wait for port to open:
Serial.begin(9600);
sensors.begin();
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
Serial.print("Initializing SD card...");
if (!SD.begin(4)) {
Serial.println("initialization failed!");
return;
}
Serial.println("initialization done.");
myFile = SD.open("logger.txt", FILE_WRITE);
// if the file opened okay, write to it:
if (myFile) {
Serial.print("Writing to the file...");
myFile.println(" ");
myFile.println("Welcome to Datalogger");
myFile.println("Time, V1, V2, A1, A2, T");
// close the file:
myFile.close();
Serial.println("done.");
} else {
// if the file didn't open, print an error:
Serial.println("error opening");
}
}
void loop() {
vc1=analogRead(0)/4.092/10;
vc2=analogRead(1)/4.092/10;
RawValue1 = analogRead(analogIn1);
Voltage1 = (RawValue1 / 1024.0) * 5000; // Gets you mV
Amps1 = ((Voltage1 - ACSoffset1) / mVperAmp1);
RawValue2 = analogRead(analogIn2);
Voltage2 = (RawValue2 / 1024.0) * 5000; // Gets you mV
Amps2 = ((Voltage2 - ACSoffset2) / mVperAmp2);

42
sensors.requestTemperatures();
temp=sensors.getTempCByIndex(0);
// Serial.print(sensors.getTempCByIndex(0));
myFile = SD.open("logger.txt", FILE_WRITE);
// if the file opened okay, write to it:
if (myFile) {
Serial.print("Writing to the file...");
myFile.print(millis()/60000);
myFile.print(" ");
myFile.print(vc1);
myFile.print(", ");
myFile.print(vc2);
myFile.print(", ");
myFile.print(Amps1);
myFile.print(", ");
myFile.print(Amps2);
myFile.print(", ");
myFile.println(temp);
Serial.print(millis()/60000);
Serial.print(", ");
Serial.print(vc1);
Serial.print(",");
Serial.print(vc2);
Serial.print(",");
Serial.print(Amps1);
Serial.print(",");
Serial.print(Amps2);
Serial.print(",");
Serial.println(temp);
// close the file:
myFile.close();
Serial.println("done.");
} else {
// if the file didn't open, print an error:
Serial.println("error opening");
}
delay(1800000);
}

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