Solar Picnic Table in Public Parks

College of Engineering

Electrical and Computer Engineering Department

Solar Picnic Table in Public Parks

 

A Capstone Final Report (ECE491)

Presented by

| Mada Alghamdi S13104917 |

Faculty Advisor

Mohamed Shehata, PhD

Submitted in partial fulfilment of the

Requirement for the Degree of Bachelor of Engineering

May 2017

Executive Summary

Sunsha is the capstone one for Arwa Alsaidalani, Mada Alghamdi and Raghad Albalawi from Electrical and Computer Engineering department in spring 2017. Umbrella is a green self-sustainable installed device that generates electricity. It is undertaken to inform the general public that how a tall device that resembles an umbrella could generate energy through the pedal affixed within it. The installation of this tall instrument proves to be really helpful to park visitors or beach goers. It not only aids in providing free service to the public so that they can recharge their smart devices but it also acts as an advertisement tool. It is also referred to as an advertising medium since the screens which are fixed within it displays ads so as to entertain the users.

Table of Contents

Executive Summary. 2

  1. Introduction.. 7

1.1          Motivation and Rationale. 7

1.2          Objective. 7

1.3          Problem Statement. 7

1.4          Problem Formulation. 8

1.5          Definition of Terms. 8

1.6          Significance of the project. 9

1.7          Capabilities of the Students. 9

2        Literature Review… 11

2.1          Historical background. 11

2.2          Review of previous methods. 12

2.3          Contemporary issues. 14

3        Project Description.. 16

3.1          System Architecture. 16

3.1.1      Solar Panel: 16

3.1.2      Charge Controller: 16

3.1.3      Battery: 17

3.1.4      Light Sensor: 18

3.1.5      USB Port: 18

3.1.6      LED light: 18

3.1.7      Pedal Powered Electricity Generator: 18

3.1.8      Screen: 18

3.1.9      Architecture. 19

3.2          Functionality. 20

3.2.1      Solar functionality. 20

3.2.2      Bike functionality. 21

3.3          Project specifications and features. 22

4        Design Methodology. 24

4.1          Assumptions. 24

4.2          Technical specification and realistic constraints: 24

4.3          Modeling. 26

4.3.1      The Equivalent of a solar cell: 26

4.3.2      I-V & P-V Curves: 27

4.4          Design. 28

4.4.1      Polycrystalline silicon solar. 28

4.4.2      Pulse Width Modulation (PWM) Charge Controller. 29

4.4.3      Monitor Display. 29

4.4.4      Battery Lead acid (12V-200Ah.): 29

4.4.5      LED Panel Light. 29

4.4.6      Photocell sensor. 29

4.4.7      USB plate coupler outlet socket panel 30

4.4.8      K-tor pedal 30

4.4.9      Structure Design: 30

4.5          Simulation. 31

4.6          Results and analysis. 32

4.6.1      Month Peak Sun Hours (PSH): 32

4.6.2      Simulation. 32

5        Project Management. 34

5.1          Cost Estimates. 34

5.2          Time line. 37

5.3          Project Risk Assessment. 38

5.3.1      Fixed solar: 38

5.3.2      Designer: 38

5.3.3      Availability of adviser and our own personal circumstances: 38

6        Conclusion.. 39

7        References. 40

8        Appendices. 42

 

 

List of Figures

Figure 1 – Smart Palm – Dubai 12

Figure 2 – Strawberry Tree. 13

Figure 3 – Bike – 5-hour Energy Company. 14

Figure 4 – WeBike. 14

Figure 5 – Solar panel system (Daytime) 19

Figure 6 – Solar panel system (Night) 20

Figure 7 – Flowchart 1 – Solar panel system.. 20

Figure 8 – block diagram for solar panel (Daytime) 20

Figure 9 – block diagram for solar panel (night) 21

Figure 10 – Flowchart 2 – Bike. 21

Figure 11 – Equivalent of a solar cell 26

Figure 12 – I-V & P-V Curves. 27

Figure 13 – Structure Design 1. 30

Figure 14 – Structure Design 2. 30

Figure 15 – Equivalent circuit for solar system.. 31

Figure 16 – Charge battery. 31

Figure 17 – I-V characteristics. 32

Figure 18 – I-V characteristics for temperature. 33

Figure 19 – P-V characteristics. 33

Figure 20 – I-V characteristics  for temperature. 34

Figure 21 – Time line. 37

 

List of Tables

Table I – LED rating. 22

Table II – Power for items. 22

Table III – Technical specification  (Pedals) 24

Table IV –  Technical specification  (Solar Panel) 25

Table V – Technical specification  (Monitor) 25

Table VI – Technical specification  (USB port) 25

Table VII – Technical specification  (Charge Controller) 25

Table VIII –  Technical specification  (Battery) 26

Table IX – Technical specification  (Photocell sensor) 26

Table X – Monthly PSH.. 32

Table XI – Cost Estimates. 36

 

1.      Introduction

1.1         Motivation and Rationale

Electricity is an essential part of our daily life. It is an imperative source of energy. The motivation got so as to embark on this project was to aid our future generations. Furthermore, this project helps the environment to produce energy from a renewable source that in turn would help in reducing pollution and the annual electricity usage cost. Moreover, this capstone project does provide more than just a direct consumer service using solar and mechanical energy. Although, the exercise is important to save our body from diseases and as the exercise can be one of the power generators for that it will be part of the system that will be implemented.

Therefore, in this capstone project, it will serve a higher aim of raising awareness within the community regarding different power sources. It is valuable in many aspects; as this project helps the environment produce energy from a clean green power supply, it helps the environment in reducing pollution and the annual cost of electricity.

1.2         Objective

The aim to design and build a green self-sustainable umbrella at parks that can be used by visitors to recharge their smart devices, and do exercises by sitting on the chair that has pedals to produce electricity is to incorporate advanced technology in every aspect of our lives. The umbrella should be capable of providing two outlets (USB port) and two plugs to recharge the smart devices and screens to display advertisements to entertain the visitors while they recharge the smart gadgets. Additionally, the project aims to show the reliability of the solar energy against the conventional energy in the Kingdom, as well as to show the efficiency of renewable source of energy in our country. It will built in Dhaban Marine Park to test its validity and to forecast its usage percentage.

1.3         Problem Statement

As a result of escalating population in Saudi Arabia, the consumption of electrical energy is increasing day by day. Furthermore, communities in Saudi Arabia generate electricity by burning oil and other traditional methods. In addition, due to the self-powered using solar energy, that can provide these services to public at least for 24 hours. The features of this umbrella can manipulated to match the requirements for each area, as it can built for public areas like parks and beaches. Moreover, it supports the mechanical energy by using the pedals under the table that connected with the plugs.  

1.4         Problem Formulation

The design of the project depends on the site chosen to apply on it. The location is Dhaban Marine Park where the wind blows at high speed most of the time so; the design must be strong enough to resist the wind. The assumptions believed in this project are based on the fact the design is made of a hard and solid material to withstand the wind. Taking into consideration that it should be appealing to public, the umbrella must installed in an innovative and attractive form.

Also, based on the fact people are not going to stay in the park the whole day, so assume it to work for at least 10 hours. The power of the system and the capacity of the battery can then calculated accordingly. Moreover, some design restrictions should apply such as, the area should be small for a certain number of persons therefore, and chairs designed to carry more people. The types of equipment used in the design were also chosen to be relatively efficient and at the same time to be inexpensive.

1.5         Definition of Terms

  • Watt: Standard unit rating of module power output (W). Watts = amps times volts.
  • Volt: Standard unit of electrical potential (V) or measure of the strength of an electrical source.
  • Amp: A measure of current (A) or quantity of electricity.
  • Vmp: Maximum power available voltage.
  • Voc: Open circuit voltage. An open circuit occurs when contacts, switches or similar devices are open and prevent the flow of current. Moreover, it used to determine if the module is within the maximum voltage of an inverter.
  • Imp: Maximum available current. Determines maximum current an array can deliver at optimum conditions.
  • Isc: Short circuit current. A short circuit occurs when there is improper connection that interrupts an electrical circuit and it used to determine appropriate fuse sizes.
  • Capacity (Ah): The capacity is the total amp-hours available when the battery discharged. It is the result of the multiplication of the discharge current (Amps) by the discharge time (hours).
  • Depth of Discharge (DOD): Is the percentage of the battery capacity has been used.
  • Cycle life: The number of times the battery can discharge / charge until the maximum charge capacity of the battery reduced to 80 % of its original capacity.
  • Standard Test Conditions (STC): It is an industry-wide standard to indicate the performance of PV modules and specifies a cell temperature of 25°C and an irradiance of 1000 W/m2 with an air mass 1.5 (AM1.5) spectrum.
  • Lumen (lm): is the SI unit of measurement for the brightness of light. The brightness of the light is proportional to the Lumen.

1.6         Significance of the project

This project is undertaken in an attempt to achieve the Vision 2030, which aims the diversification of energy sources. In addition, since the Dhaban Marine Park has lack of enough energy, it is therefore an ideal choice to begin to realize the vision of the country. The project is solar powered so, it will raise awareness within the community about renewable energy, as it helps the environment to produce energy from clean green supplies. Also, it helps the environment to reduce air pollution as well as reduce the annual cost of electricity that is used in the public areas. Hopefully it will be applied in all the parks throughout the kingdom.

1.7         Capabilities of the Students

Since the team members are Electrical and Computer Engineering students and have studied several courses that covered topics related to this project; the team members will be able to understand the different aspects needed to implement this project including Complex Electrical Circuits. The project scope is mainly laid in Renewable, Mechanical Energy Field, yet it also covers many areas such as Power Systems, Control, Computer Simulation, and Power Electronics.

The renewable energy field is a common interest of all engineering majors; the contribution in such area is always needed as it helps the world go green with clean energy. Therefore, the team is keen to take the chance forward to construct a green energy power supply whose source is the Solar Power and Mechanical Energy and to develop the design in hope to contribute to the development of the renewable energy field.

2           Literature Review

2.1         Historical background

The first project was developed in Saudi Arabia in PV solar, Solar Village in 1981. It was conducted by the Energy Research Institute (ERI), KACST. The Solar Village Project was designed with two modes of operations; stand-alone and co-generation. Its aim was to supply power to almost 3000 inhabitants in remote villages that are not served by an electric power grid. The peak output of the system was 350 kW of direct current (DC) with,1100 kWh lead-acid battery storage, 300 kVA inverter that form 160 PV arrays was covering an area of 4000 m2[1]. Also, it was followed by another project at same capacity of 350 kW in 1993 to produce hydrogen, but these two projects did not see any considerable difference until a 2 MW solar PV project was developed in King Abdullah University of Science and Technology (KAUST) in 2010. It was in the roof of the University’s main academic campus buildings. In 2011 Saudi ARAMCO developed a 10 MW solar car parking project [2].

2.2          Review of previous methods

Nowadays, the whole world is trying to provide renewable energy in public areas to show that clean energy such as solar energy is not an abstract concept. There are many projects established worldwide that offer a place for the public to sit and charge their personal electronic devices by using solar energy.

For instance, The Smart Palm is a new innovation technology in Dubai’s parks and beaches (2.2.1). It is green self-sustainable station powered by MonoCrystal solar panel with 21% efficiency. It took just ten months from conception to delivering the finished product.

Also, it provides to the public free topics on the touch screen. In addition, they can used to quickly charge tablet computers and mobile phones as well [3] direct access to the internet. Moreover, it can display information on Dubai’s attractions, weather and other.

Figure 1 – Smart Palm – Dubai

Strawberry Energy company did a similar project named The Strawberry Tree  public solar stations were established at public venues in Europe, to increase awareness for people about clean energy. The design has 16 charging cords, so users do not need to bring the charger with them. Also, it has Wi-Fi hotspots for free to people and it serves as a meeting area [4].

Figure 2 – Strawberry Tree

In India especially in poor villages close to Lucknow, Amethi and Raebareli in the north Indian state of Uttar Pradesh, (5-hour Energy Company) Manoj Bhargava, founder and the CEO of the company behind spearheading an ambitious project to power homes in poverty-stricken areas came up with a revolutionary idea of using stationary bikes. (2.2.2) Instead of spending that money on luxury items or a lavish lifestyle, he’s focused on making a difference in the world by tackling some of the pressing issues of our time, most notably energy and water. Bhargava aimed to have a first batch of 10,000 bikes distributed by the third quarter of 2016. Pricing will range from free to $250, depending on people’s ability to pay for the bike [5].

Figure 3 – Bike – 5-hour Energy Company

We Watt Belgian Company located in Leuven is part of the innovative network of Leuven Mind gate and Flanders’ Bike Valley. They invented We Bike that is a combined table and seat unit equipped with pedals that allow those who are sitting at the table to pedal as if they are riding a bicycle. The energy gathered from the pedaling is then used to charge devices such as laptops and cell phones, etc. They bullied the product from recycling material.  Now, their products used in many places around the world such as King Abdullah University – Saudi Arabia. [6]

Figure 4 – WeBike

2.3         Contemporary issues

All energy sources affect our environment with varying degrees. Oil, and natural gas, for example, do substantially more harm than renewable energy sources. Environmental effects include air and water pollution, and carbon dioxide emissions that jeopardizes the public health and intensifies Global Warming.

In 2011, Saudi Arabia ranked the 10th globally, in carbon dioxide emissions from all sources of fossil fuel burning and consumption [7]. Furthermore, recently, electricity consumption is unfortunately, increasing since 1980, and it grew by 9% in 2012 compared with the previous year. According to Arab News, Saudi Arabia consumes three times more electricity than any country in the world.

It comes in the third place for Electricity consumption per capita, directly after Qatar and Australia [8]. Also the geography of the country increases the uses of the electricity, as Saudi Arabia, Qatar, and Australia are in extremely hot places, which make them use air conditioning more than other countries.

Renewable energy can reduce the temperature and increase rates if we use it instead of conventional energy sources. In fact, as an important aspect of the 2030 vision, it will decrease the pollution and increase green areas. Also, it will reduce Global warming, since, as we’ve seen, Saudi Arabia is one of the largest energy consuming countries.

 

3           Project Description

3.1         System Architecture

Based on the functional and operational requirements of the system, it includes solar panels, charge controller, battery, light sensor, USB port, LED light, pedal powered electricity generator and screen.

3.1.1        Solar Panel:

The main part of the solar electric system is solar panel. There are three types of solar panel in commercial production and are based on silicon semiconductors. First, Monocrystalline is made from thin wafers of silicon and it is produced from single crystals because of that it is more expensive than other types. Also it has the highest efficiency rating – between 15-24%. Sometimes it is used in combination with concentrators such as mirrors or lenses. Concentrating systems can be used to boost efficiency to approximately 30 percent. Monocrystalline comprise 29% of the global market for PV. Second polycrystalline is also made from thin wafer but create from multiple silicon crystals and this making it cheaper .It has efficiency rating – between 13-18%. Polycrystalline cells comprise 62% of the global PV market. Third, Amorphous is the cheapest type of solar cell. It is made from thin layer of silicon that makes it more flexible and more efficient in low light levels. It has the lowest efficiency rating of all three types approximately 7% – 9%. There are some materials other than silicon are under development such as gallium arsenide (Ga-As), V, and copper-indium-selenide (CuInSe2).These materials provide properties such as high efficiency and capture more of the available light.

3.1.2        Charge Controller:

A charge controller is also known as charge regulator. It limits the amount or current and voltage going in the battery in order to protect the battery from getting overcharged. In PV systems there are two most common installed charge controllers are Pulse Width Modulation (PWM) and Maximum Power Point Tracking (MPPT).

Pulse Width Modulation (PWM) is uses pulse width modulation that aims to get a constant voltage output from the PV panels to charge the battery with the same voltage as the battery. The drop in voltage causes loss in wattage. When looking for a PWM charger controller it is important to consider the compatibility of the current and voltage. It has advantages such as cheaper than MPPT controller, used for small systems only does and it has small size but, it has some disadvantages such as limited capacity for system growth and not all batteries will work with it.

Maximum power point tracking used to regulate charge. The charge controller looks at the output of the PV panels, and compares it to the battery’s voltage. Then finds the best power that the panel can output to charge the battery. It takes this and converts it to best voltage to get maximum current into the battery. Most MPPT’s are around 93-97% efficient in conversion. There is a 20 to 45% power gain in winter and 10-15% in summer. The amount of power gain depends on weather, temperature and battery’s state of charge. Some MPPT charge controllers are used in a panel tacking PV system. Where the PV panels are mounted on trackers that follow the sun in order to get the maximum sun exposure by allowing the panels to get a 90° angle with the sunrays. It has advantages such as it gives high efficiency in low temperatures, it is more flexible for system growth and it works with most batteries .It has some disadvantages such as it is expensive and has a large size.

3.1.3         Battery:

There are two types of batteries are non-rechargeable and rechargeable. Non-rechargeable is also known as primary batteries are designed to used once and discarded. They have some advantages such as long shelf life, high energy density, low cost and high functionality under low temperatures. On the other hand, they require high power while in use and they will not last long with high startup current requirements. They used in toys, flashlights, and watches. The popular chemical components used are Alkaline and Aluminum-ion. The rechargeable batteries are secondary batteries. They have the advantage of long life, high energy density and ability to charge before full discharge, but they are last for 4 -5 years depending on the use, sensitive to high temperatures and Expensive. The popular chemical components used are Lead-acid and Lithium-ion.

 

3.1.4        Light Sensor:

A light sensor is an electronic device used to detect light. There are several types of light sensors such as a photocell or photoresist or is a small sensor which changes its resistance when light falls upon them. It has used in robotics as a sensor to follow a line as well as in streetlight to switch on and off depends on whether it is night or day. Photocell is small in size and inexpensive also it has the ability to detects all kinds of light in all kind of conditions. It has some drawback such as it does not respond immediately to the presence of light and when the light source is removed, it is very slow to return to its original state.

3.1.5        USB Port:

Uses universal serial port (USB) used to connect devices, as well as allow for high data transfer. It is also used to charge personal devices with a current limit of 500 mA and 5V.

3.1.6        LED light:

The LED emitting diode (LED) is a two-lead semiconductor light source. LEDs have many advantages over incandescent light sources, including low power consumption, longer lifetime, and smaller size. Also, it is cheaper than a compact fluorescent lamp and more energy efficient.

3.1.7        Pedal Powered Electricity Generator:

Pedals are used with legs to generate electricity as a bicycle. It has a universal port that allows charging portable electronics. Designed with small size and high efficiency.

3.1.8        Screen:

There is two types of screen displays are liquid-crystal displays (LCD) and Light-emitting diode (LED). LCD monitors have produced a high-quality image with a competitive price. In contrast, LED monitors produced brighter and more vibrant images using backlighting. In addition, they have less power consumption than LCD.

 

3.1.9        Architecture

All components of the electrical system are integrated together to implement the overall design as presented in the following figures.

Figure 5 – Solar panel system (Daytime)

Figure 6 – Solar panel system (Night)

3.2         Functionality

3.2.1        Solar functionality

In (Flowchart1) shows functional of the solar system. It start during the day light if there is sun light the solar panel receive the sun light and distributes the energy  to devices if they needed but if there’s no devices need power, the battery receive the energy and save it. While during the night, the battery distributes the power to devices.

Figure 7 – Flowchart 1 – Solar panel system

Figure 8 – block diagram for solar panel (Daytime)

The figure shows a functional block diagram of the system during the daytime. In the presence of sunlight, the system should convert the solar energy to electrical energy. The generated electrical energy should drive all electrical charging services in addition to filling up the battery bank. During daytime, there is no need for turning on any station lighting. Thus, the system should be responsible for detecting this condition and turn the lights off.

Upon the absence of sunlight, the system should be able to use the energy stored in the battery bank to drive all electrical charging services in addition to powering the smart station lighting throughout the night. Moreover, the light sensor should be monitored to detect the darkness, and switch ON the LED lights.

Figure 9 – block diagram for solar panel (night)

3.2.2        Bike functionality

In (Flowchart2) shows functional of bike system. It starts when someone sit  in the sit bike and use the pedal to convert the mechanical energy to electricity and the energy use direct by USB or save it in battery. 

Figure 10 – Flowchart 2 – Bike

3.3         Project specifications and features

The system will provide a shaded area powered from solar energy outdoor for people at the parks or beach sides. It has chairs to sit under the shade and people can charge their own electronic devices from the USB port. Also, it has a large digital screen hanging on the wall for viewing the new advertisements. In addition, it will supply light during the night. The system has a pedal under the table which is connected with USB port that can charge smart devices.

Moreover, the efficiency of the system is high which can provide perfect light at night and charge the phones using safe energy from solar and kinetic energy. In addition, the system does not use converted power from DC to AC because it depends on DC and this will decrease power losses.

Calculations used:

The LED light power rating can be calculated based on the following specifications:

Height of the pole 2.5 meter
Area 6 m2
Location Outdoor
Temperature range 0 – 50oC

Table I – LED rating

Based on Reference [9] and [10], a LED lamp rated Power based on Part C [10]:

Lumen on area required = 2800 Lumens (43% efficacy)

LED Power =2800/110 = 25 Watt (LED Lamp used have 110 Lumen /Watt)

 

For other Loads

Item Type Number of items Power
USB port for Phone chargers 2 10 Watt
LED TV Screen 1 36 Watt

Table II – Power for items

 

 

 

To calculate the solar panels size, the following assumptions have been taken in consideration:

  • The round trip efficiency of the battery storage is 80%
  • The charge controller used is PWM type due to small PV system. Thus, for a 24 V dc battery storage 250 Watt panels are used and connected in parallel to have a maximum power point voltage of 30 Vdc. That will maximize the conversion efficiency of the charge controller to above 90%.
  • The load will be running for 13 hours maximum.

System losses:

  • losses due to soiling is 10% , monthly cleaning
  • battery losses 20%
  • 3- PWM charger controller losses 8%
  • 4- wiring resistive losses 4%
  • Total losses = 42%

That means:

Total minimum size of  solar module = Total energy/ (solar irradiation x efficiency)

Total conversion efficiency from the solar panel to the load = 58%

Total solar panel rating=  Watt

Take two 250 Watts solar panels. So total ratings is 500 Watt.

Battery storage size (Ah) =  210 Ah. (40% DOD)

Taking two days autonomy= 420 Ah. So, it is acceptable to take 400 Ah battery storage (two 200 Ah).

4           Design Methodology

4.1         Assumptions

Depending on the location of Dhaban Marine Park the design for umbrella should endure the wind. In addition, it designed in rectangular so the table can easily adjust the maximum number of people to sit. Additionally, the column for this design will be in the end of the seat, since everyone can see the advertising on screen. If the solar panel is  placed in fixed position and the daylight duration is 13 hours, the assumed time of battery to be fully charged is between 11 am – 16 pm. For that, the assumed power for the USB port to be used is 10 hours per day with the maximum power consumption of 10.71 kW. The aforementioned power is for devices like iPad and tablets because they consume power in large numbers and therefore they are considered as the worst case for charging devices using two USB ports. In this case, the power loss from USB port is 214.2W. On the other hand, the presumed power for the monitor to work is 10 hours, and the total power consumption turns to be 360 kW. Also, generating power from bicycle’s pedal gives an expectation that people will like the revolutionary idea of charging devices using advanced technology and the assumption to be made is that if this project is undertaken, it may increase the awareness about power use using renewable sources of energy.

4.2         Technical specification and realistic constraints:

Pedals           Technical specifications
Power 20 w
Efficiency 85%
Material Type Steel
Dimensions 5.5 x 3.5 x 12 inches
Volt 120 V
Table III – Technical specification  (Pedals)
Solar Panel Technical specifications
Type of solar Polycristyline siclicon
Watt at STC 250 w
Max Power Volts 30.9 v
Open Circuit Voltage 36 v
Short Circuit Current 8.7 A
Max Power current 8.5 A
Power consumption 25 w
Intensity 2800 lumen
Dimension 1m x 2m
Volt 12 v

Table IV –  Technical specification  (Solar Panel)

Monitor Technical specifications
Type LED
Dimension 22 inch
Maximum Power Consumption 36 w
Maximum Current 1.2 A
Voltage 12 VDC

Table V – Technical specification  (Monitor)

USB port Technical specifications
Currant 4.2A
Voltage 5V DC
Dimension    5.2 x 3.2 x 2 inches

Table VI – Technical specification  (USB port)

Charge Controller Technical specifications
Type PWM
Current  30 A
Voltage 12/24 V

Table VII – Technical specification  (Charge Controller)

Battery Technical specifications
Type Deep cycle
Capacity 200 Ah
Voltage 12 V
Temperature  25 oC

Table VIII –  Technical specification  (Battery)

Photocell  sensor Technical specifications
Voltage 12VDC
Current 10 A
Turn On 1-3 Footcandles
Time Delay 1-5 Seconds
Dimension  3 1/2″L x 1 1/4″W x 1/4″D

Table IX – Technical specification  (Photocell sensor)

4.3         Modeling

4.3.1        The Equivalent of a solar cell:

To comprehend the electronic conduct of solar cells, it is helpful to make a model which is electrically equivalent and depends on discrete electrical components whose conduct is well defined. An ideal solar cell behaves as a current source, which is connected in parallel with a diode, then connected with a shunt resistance and a series resistance because in practice there is no ideal solar cells.

Figure 11 – Equivalent of a solar cell

       

Equation 1 – Current

Where:

   is the photocurrent provided by the constant current source.

  is the reverse saturation current related to the diode. Rs is the series resistor.

 is the shunt resistor that the current leakage through the high conductivity shunts across the p-n junction; and a is the ideality factor from the Shockley diffusion theory.

        

Equation 2 – Voltage

Where:

 it is the thermal voltage of the diode and depends on  the charge of the electron,  is the Boltzmann constant,  the number of cells in series, and  the temperature.

4.3.2        I-V & P-V Curves:

  • Short Circuit Current (Isc):

When the PV cell is short-circuited the voltage across the PV cell is at the minimum value (0V) however the current going out the cell reaches its maximum value as shown in the equation:

Figure 12 – I-V & P-V Curves

Equation 3 – Isc

  • Open Circuit Voltage (Voc):

When the PV cell is not connected to any load, the current will reach its minimum value (0A) and the voltage across the PV cell will reach its maximum value as shown in equation:

Equation 4 – Voc

  • Maximum Power Point (MPP):

The voltage and current at this Maximum Power Point are termed as Vmp and Imp. An ideal PV cell should work with these values to get maximum power.

4.4         Design

4.4.1        Polycrystalline silicon solar

The chosen polycrystalline silicon solar depending on its features as it cost is less than other types of solar. The temperature in Jeddah is high and heat can affect the performance of solar panels, but the polycrystalline silicon doesn’t reduce the efficiency as much as monocrystalline solar panels.

4.4.2        Pulse Width Modulation (PWM) Charge Controller

Pulse width modulation use to get a constant voltage output from the PV panels to charge the battery with the same voltage as the battery. It is less expensive than other charge controllers and it is suitable for small systems powered by solar energy also, it has small size.

4.4.3        Monitor Display

Depending on the use of Monitor Display the LED is the ideal choice because the resulting better picture quality, energy saving, longer lifespan and environment protection at the same time.

4.4.4        Battery Lead acid (12V-200Ah.):

The batteries used are Lead-acid. Due to high performance, least energy density by weight and performance and deep cycle batteries, designed to regularly discharge and charge again without losing neither capacity nor cycle life.

4.4.5        LED Panel Light

The LED panel light have low power consumption and the lighting technology is a green lighting technology. The LED does not contain mercury, the semiconductor lighting can be recycled. Which is very important for sustainable development. Also it can be adjusted according to the different needs or circumstances. Furthermore the LED panel lights have long life.

4.4.6        Photocell sensor

It is used in outdoor lighting to detect the level of light and operates automatically, so no need to set a timer or turn the light manually. It saves energy with minimal setup and maintenance required.

4.4.7        USB plate coupler outlet socket panel

For public places, the USB port is the best choice to charge devices and they feature a higher speed for USB runs at up to 12 Mbit/second. It has single Interface for multiple devices and the power consumption is low because the USB devices generally work on +5V and consume current in milliamp ere.

4.4.8        K-tor pedal

The K-tor is a simple pedal that can produce energy up to 20 Watts. And the generator output converts it to 120 Volts DC with 85% efficiency rate. It is used for all portable electronics because they are very efficient. The K-tor size is 12 x 5.5 x 3.5 inches which is better for the design implementation.

4.4.9        Structure Design:

In collaboration with the interior designer, Alaa provided the following structure design. It presents the expected overall design with seating area, LED overhead cover by solar panels and advertisement monitor. In addition, charging outlets and pedals.

Solar panel
Monitor Display
USB Port

Figure 13 – Structure Design

Power Plug
K-tor Pedal
LED

Figure 14 – Structure Design 2

4.5         Simulation

Used Simulink in Matlab software to simulate the system (Figure15) shows the equivalent circuit for the solar system

Figure 15 – Equivalent circuit for solar system
Figure 16 – Charge battery

Used the rustle of equivalent circuit to simulate the system by charge battery this shown in (Figure16)

4.6         Results and analysis

4.6.1        Month Peak Sun Hours (PSH):

Month PSH
Jan 4.38
Feb 5.28
Mar 6.11
Apr 6.75
May 7.13
Jun 7.09
Jul 7.01
Aug 6.39
Sep 6.08
Oct 5.51
Nov 4.57
Dec 4.02

Insolation is the amount of hours where the sun is at its peak. It is also called peak sun hours (PSH). This allows  to design the system based on the worst case. The average Peak Sun Hours in Jeddah is 6.2 kWh/  per day. In December to go as low as 4.02 kWh/  per day. Therefore it is considered the worst case and based on that the system is designed.

4.6.2        Simulation

Table X – Monthly PSH

The mathematical models for the solar cell series with resistance implemented in Simulink/ Mat lab.

The I-V characteristics for the module, shown in in (Figure17)

Figure 17 – I-V characteristics

The I-V characteristics for a temperature variation in 0⁰C, 25⁰C and 50⁰C, considering the solar cell, shown in (Figure18)

Figure 18 – I-V characteristics for temperature

The P-V characteristics for the module, shown in in (Figure19)

Figure 19 – P-V characteristics

The P-V characteristics for a temperature variation in 0⁰C, 25⁰C and 50⁰C, considering the solar cell, shown in (Figure20)

Figure 20 – I-V characteristics  for temperature

From the above result found an inverse relationship between current and voltage. Therefore, both affect the power.

5           Project Management

5.1         Cost Estimates

Most components are supplied from a Renewable Current Establishment at a reasonable cost to the Investor’s budget.

Item Quantity Price Picture
Solar charge controller 1 160 SR
Solar panel 2 2×750=1500 SR
Monitor Display

Led TV 12V

1 1000 SR
Battery (Lead acid) 2 2400 SR
LED Panel Light 2 200 SR
2 × USB plate coupler outlet socket panel 1 50 SR
Cables** 20 meter 80 SR
MC4 Construction 2 50 SR
K-tor pedal  

 

 

2

 

 

 

946 SR

Photocell sensor 1 74 SR
Construction  

1

 

 

4000 SR

Total Cost + Shipping 10460 SR

Table XI – Cost Estimates

5.2         Time line

Figure 21 – Time line

5.3         Project Risk Assessment

5.3.1        Fixed solar:

The system used fixed solar panels so; it received rays of the sun from one side. To avoid any problem and confusion, study the coordinates of the region and know the direction of the sun’s rays well.

5.3.2        Designer:

As electrical engineering students don’t have enough knowledge about design structure and to choose the proper materials to build it, a designer was collaborated to undertake this project on the availability of adviser and our own personal circumstances.

5.3.3        Availability of adviser and our own personal circumstances:

The Advisor of project PhD. Mohammed Shehata he is instructor at Effat University in ECE department so, he has classes. Also, he is response about IEEE branch at Effat and GCC robotic competition for that he had a lot of trips around KSA, Egypt and GCC country. To avoid this problem we contact by email and phone. On other hand we had our own personal circumstances, our schedules are different and one of us had training in Company so we had a difficulty with scheduled our time per week day for that we made all our meeting after working time in public place or at weekend.

6             Conclusion

Taking into consideration the present situation of this world, it is likely to stress on the fact that it is a high time to initiate the use of sustainable resources for all basic purposes.

Sustainable resources are those resources that serve the present need of humans without compromising the ability of future generations to meet their needs. (6.1) Technology plays a vital role in attaining a sustainable system. It massively promotes the use of renewable energy sources such as the solar energy is an immense source of directly usable energy and ultimately creates other energy resources. Today, technologies are designed to improve energy efficiency. Considerable progress is being made in the energy transition from fossil fuels to ecologically sustainable systems, to the point where many studies support 100% renewable sources of energy.

There are many possible ways of demonstrating how solar energy can be used. One way would be to demonstrate physically, such as building a model that runs on solar energThis project was mainly undertaken due to the immediate concern of using sustainable resources in countries like KSA. By installing the umbrellas powered by the solar energy, it not only helps the common public in the humdrums of their lives but it also raises awareness regarding the various sources of energy. Projects such as this aspire the general public of the upcoming advancement in the field of technology.

7           References

[1] Hurair, F.S.; Hasnain, S.M.; Alawaji, S.H. Lessons learned from solar energy projects in Saudi Arabia. Renew. Energy 1996, 9, 1144–1147. [Accessed 2017].

[2] M. A. (3 November 2016). Urban Scale Application of Solar PV to Improve Sustainability in the Building and the Energy Sectors of KSA. 1-11 [Accessed 2017].

[3] Smart Palm. (2015). Why the Smart Palm. Retrieved October 16, 2016, [online] Available at: http://smart-palm.com/ [Accessed 2017].

[4] Solar Technology-strawberry trees offer free public (2013) [online] Available at:, www.senergy.rs [Accessed 2017].

[5] Mail Online. (2016). Free Electric’ Bike Creates 24 Hours Of Electricity. [online] Available at: http://www.dailymail.co.uk/sciencetech/article-3462885/The-electricity-generator-pedal-Free-Electric-bike-create-24-hours-electricity-just-hour-exercise.html [Accessed 2017].

[6] We watt | Human Powered Bike Furniture, Pedal Table, Cycling Desk. [online] Available at: http://wewatt.com/ [Accessed 2017].

[7] KSA Power Consumption 3 Times World Average (2014). Arab News. [online] Available at: http://www.arabnews.com/news/598481 [Accessed 2017].

[8] “Each Country’s Share Of CO2 Emissions”. Union of Concerned Scientists. N.p., 2014. Web. [Accessed 2017].

[9] Nano Education-Safety Light Levels outdoor and indoor [online] Available at: www.noao.edu,1998 [Accessed 2017].

[10] Foot candle Recommendations by Guth [online] Available at: www.bristolite.com,2000 [Accessed 2017]

Components reference

The green age -Types of solar panels , www.thegreenage.co,2016 [Accessed 2017].

Solar Direct-Complete Photovoltaic Systems, www.solardirect.com,1986 [Accessed 2017].

Battery and Energy Technologies -primary, www.mpoweruk.com,2005 [Accessed 2017].

Battery and Energy Technologies –Secondary, (2005) [online] Available at:  www.mpoweruk.com [Accessed 2017].

Electronics -Photocells, (1994) [online] Available at:  www.sciencing.com [Accessed 2017].

Charging from a USB port [online] Available at:  www.batteryuniversity.com,2011 [Accessed 2017].

Light emitting diode, [online] Available at: en.wikipedia.org  [Accessed 2017].

The Power Box-Pedal powered generator, [online] Available at: www.k-tor.com,2011 [Accessed 2017].

Engineers Garage, (2013) – difference between lcd and led display [online] Available at:  www.engineersgarage.com [Accessed 2017].

8           Appendices

(2.2.1) Smart palm trees have been installed and are ready for use in Dubai this summer enabling beach goers and park visitors to have limitless power and internet access on their mobile phones. Soaking up the sun during the day, these state-of-the-art trees store energy to be discharged in the evening. On each tree, there are eight charging points and WiFi ranges for 100 meters in any direction.

(2.2.2) Manor Bhargava is an Indian American businessman and philanthropist. He is the founder and CEO of Innovations Ventures LLC (dba Living Essentials LLC), the company known for producing the 5-hour Energy drink. By 2012 the brand had grown to do an estimated $1 billion in sales. In 2015, Bhargava pledged 99% of his net worth to improving the wellbeing of the worlds less fortunate.

(6.1) Sustainable energy is energy that is consumed at insignificant rates compared to its supply and with manageable collateral effects, especially environmental effects. Another common definition of sustainable energy is an energy system that serves the needs of the present without compromising the ability of future generations to meet their needs. The principle for sustainability is sustainable development which includes four interconnected domains.

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