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What is the meaning of renewable energy?

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Presentation on theme: "What is the meaning of renewable energy?"— Presentation transcript:

1 What is the meaning of renewable energy?
Our current sources of energy is running out. Our current sources of energy gives out harmful wastes. Why is there a need for alternative sources of energy?

2 Renewable Energy Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable (naturally replenished).

3 Renewable Energy Wind power Hydropower Solar energy Biomass Biofuel Geothermal energy How can one of this source of energy be employed in one area of your life?

4 Future of Transportation
In the coming decades, transportation is expected to change radically in response to environmental constraints, fluctuating oil availability and economic factors.

5 Future Decision-Makers
The transportation systems that emerge in the 21st century will be defined largely by the choices, skills and imaginations of today’s youth.

6 Future Workforce As scientists and engineers, they will develop new vehicle and fuel technologies. As citizens, they will make decisions balancing mobility, environmental, and economic needs.

7 Social Implications Students are encouraged to consider the influence of transportation on social and economic patterns, energy use and the environment. JSS is an excellent opportunity to combine the teaching of scientific and social principles in an atmosphere of fun and excitement.

8 Solar Car CID Generate enthusiasm for science and engineering at a crucial stage in the educational development of young people. Improve students' understanding of scientific concepts and renewable energy technologies; and Encourage young people to consider technical careers at an early age.

9 Solar Car CID Students use mathematics and science principles together with their creativity in a fun, hands-on educational program Using engineering principles, students get excited about generating ideas in a group and then building and modifying models based on these ideas Students can see for themselves how changes in design are reflected in car performance

10 Solar Car CID This CID challenges students to use scientific know-how, creative thinking, experimentation, and teamwork to design and build high-performance model solar vehicles.

11 Solar Car CID What is involved in this CID:
Understanding of world issues: Alternative energy sources Application of Physics: Aerodynamics Force Motion Teamwork How design effects function Problem solving

12 What Teachers are looking out for
Highly motivated students who accepts and works on the challenge with excitement Students thinking on their feet and reacting quickly Perseverance to complete the task and improve on their car Active participation in a competitive situation

13 Group Report In your Report, you are to consider:
Social implications: the influence of transportation on social and economic patterns, energy use and the environment.

14 Need for Alternative Source of Clean Energy
Global Warming Rising Sea levels Flooding of Coastal regions Outbreak of diseases

15 Objective understand how solar panels work
understand the factors affecting the efficiency of the working of solar panels. understand how Newton’s Laws governs motion. Understand energy conversion in solar cells and when it is in motion.

16 Mission Construct a car from raw materials that can run on solar energy. Your car should resemble an animal.

17 Mission Task To build a solar car that resembles an animal and can
race in the shortest time to complete a 2.0 m horizontal track, race the greatest height up a small inclined of 300.


19 Materials and Apparatus
3 solar panels soldiered in series Motor batteries Wheels and axle Wooden block Light Meter Multi-meter

20 Some solar cars

21 4 Assessments Group report Individual report Oral Presentation
Mission Task Assessment

22 Timeline Weeks 1, 2 and 3: Introduction, formation of groups, research and design, report writing Week 3: submission of group report, building solar car Weeks 4, 5 and 6: Building solar car, modifying and test run of solar car Week 7: Competition Week 8: Preparation for oral presentation Week 9: Oral presentation Week 10: Reflection (Individual report)

23 Design Process

24 First Task Get into groups of 3. Elect a leader amongst you.
Submit the names of group members (and class) to me – indicate the leader.

25 Group Report 2 page type-written (max 3 pages) Deadline Term 3 week 3
Areas to cover: What is the impetus behind the development of Solar Cars How does a solar car work? How is solar energy converted to electrical energy? What are the design considerations for a solar car? What is the material and design you have chosen? Justify. What are the factors affecting the motion of the solar car?

26 End

27 Individual Report Completed in class


29 Newton’s First Law Newton’s First Laws states that when the resultant force acting on the object is zero, an object that is at rest will remain at rest and an object that is in motion will continue with motion in a straight line at constant velocity.

30 Newton’s 1st law of motion
In short, Forces are balanced / Zero Resultant force Object at rest, v = 0 m s-1 Object in motion, v ≠ 0 m s-1 Remains at rest, v = 0 m s-1 where a = 0 m s-2 Remains in motion with same speed & direction where a = 0 m s-2

31 Newton’s Second Law Newton’s Second Law states that when a resultant force acts on an object it will accelerate in the direction of the resultant force with the resultant force being equal to the product of mass and acceleration. The (resultant) of all the forces acting on an object = mass of object x acceleration of object FR = m a

32 Horizontal Forces acting on car
Horizontal forces influences horizontal motion. Forward driving force from motor Frictional Force Air Resistance

33 Forces acting on a car Resultant force (FR, ) = Mass x acceleration
Resultant Force (FR) = Driving Force –(Friction + Air Resistance) Air Resistance Friction Friction Driving Force

34 Factors affecting Horizontal Forces : Friction
As the car moves, it will have frictional force with the ground. The frictional force is affected by the nature of the surface of the wheels and the ground and the weight of the car. The less rough the two surfaces are and the smaller the weight of the car, the smaller will the the Frictional force. The smoother the surfaces between axle and wheel the lesser is the resistance to motion.

35 Factors affecting Horizontal Forces : Air Resistance
The Air Resistance or Drag depend on the shape of the car. The more streamline it is the lower the air resistance. What is a streamline shape? (For you to research)

36 Factors that increases car’s acceleration
The larger the driving force The smaller the friction The smaller the Air Resistance The smaller the mass

37 Accomplish Missions The faster it moves the more kinetic energy the shorter it the time taken to travel the specified distance. The faster it moves the more kinetic energy it has the further is will rise up the incline as the kinetic energy is converted to gravitational potential energy.

38 What is a solar panel made of ?
Solar panels are composed of and can be made of various semi conducting materials, especially Silicon. These are in layers which consist of different types of Silicon – mono crystalline Silicon, Polycrystalline Silicon and Amorphous Silicon – and there is a transparent anti-reflection film that protects the cell and decreases the reflective loss on the surface of the cell and panel. The different types of Silicon increase the efficiency of the solar cell and they are more cost efficient compared to using pure Silicon.

39 How does Solar Cell work?
Semi-conductors like silicon and germanium are not very conducting in its pure form. Doping is a process of adding impurities into the semi-conductors The solar cells are produced by “doping” and when the different layers of the silicon or other semi conductors are combined, a so called p-n-junction will be formed on the boundary of the layers. At these junctions, an interior electric field is built up which causes the charge carriers that are released by light to be separated. And when an electrical load is connected, an electric current will flow.

40 Doping Semi-conductors

41 Doping In doping, the electrical properties of the semiconductors are permanently modified by introducing impurities. Usually, it is sufficient to approximate that each impurity atom adds one electron or one "hole" that may flow freely. Upon the addition of a sufficiently large proportion of impurity dopants, semiconductors will conduct electricity nearly as well as metals. Depending on the kind of impurity, a doped region of semiconductor can have more electrons or holes, and is named N-type or P-type semiconductor material, respectively. As mentioned before, the junctions between regions of N- and P-type semiconductors create electric fields, which cause electrons and holes to be available to move away from them, and this effect is critical to semiconductor device operation. Also, a density difference in the amount of impurities produces a small electric field in the region which is used to accelerate non-equilibrium electrons or holes.

42 A solar panel

43 Photovoltaic effect The solar cells works in what is known as the photovoltaic effect. The photovoltaic effect is the basic physical process through which a PV cell converts sunlight into electricity. Sunlight is composed of photons--packets of solar energy. When photons strike a PV cell, they are either reflected or absorbed, or they may just pass right through. The absorbed photons generate electricity. Their energy is transferred to an electron in an atom of the semiconductor device. With its newfound energy, the electron is able to escape from its normal position associated with a single atom in the semiconductor to become part of the current in an electrical circuit. Special electrical properties of the PV cell have a built-in electric field that provides the potential different to drive the current through an external load.

44 Photovoltaic Effect

45 Factors that affect the efficiency of the Solar Panels
Factors that can affect current output which will then determine how fast a car runs are light intensity, temperature and surface area of exposure and angle of incidence of the sun’s rays. While light intensity is one of the factors which affect current output, the dominant factor which greatly increased the current output is temperature. However, there is also an optimum range of temperature for each solar cell and an increase surface area of exposure can increase the power output of the solar cells.

46 Power output against temperature of the solar cells

47 Power Output against temperature
The amount of output (product of current and voltage) of a solar cell is determined by two main factors, mainly light intensity and temperature. However, temperature affects the output more, compared to light intensity. The hotter the solar panel, the lower the power output. In other words, higher cell temperatures lead to lower output, and hence to lower efficiency. The optimum temperature that achieves the maximum output is 30 0C to 43 0C for this particular solar panel.

48 Power output against light intensity
As for light intensity, the higher the light intensity, the larger the output. However, the output obtained is a lot lesser than the output obtained from higher temperatures. Therefore, the dominant factor for the efficiency of the solar panel is temperature and not so much of light intensity.

49 Parallel connection of Solar Panels
In parallel arrangement, the current output is equal to current in the branches while the voltage is constant.  For example, if we have cells that are 0.5 V each and 0.1 A each then: Atotal = A1 + A2 = 0.1 A A = 0.2 A Power = 0.5 V x 0.2 A = 0.1 Watt

50 Series Connection However, if the arrangement is in series, the voltage is sum of the voltage of each cell while the current is constant. This can be shown through this: Vtotal = V1 + V2 Vtotal = 0.5 V V = 1.0 V Power = 1.0 V x 0.1 A = 0.1 Watts

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