Presentation on theme: "What is the meaning of renewable energy?"— Presentation transcript:
1What 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?
2Renewable EnergyRenewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable (naturally replenished).
3Renewable EnergyWind powerHydropowerSolar energyBiomassBiofuelGeothermal energyHow can one of this source of energy be employed in one area of your life?
4Future of Transportation In the coming decades, transportation is expected to change radically in response to environmental constraints, fluctuating oil availability and economic factors.
5Future 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.
6Future WorkforceAs scientists and engineers, they will develop new vehicle and fuel technologies.As citizens, they will make decisions balancing mobility, environmental, and economic needs.
7Social ImplicationsStudents 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.
8Solar Car CIDGenerate 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; andEncourage young people to consider technical careers at an early age.
9Solar Car CIDStudents use mathematics and science principles together with their creativity in a fun, hands-on educational programUsing engineering principles, students get excited about generating ideas in a group and then building and modifying models based on these ideasStudents can see for themselveshow changes in design arereflected in car performance
10Solar Car CIDThis CID challenges students to use scientific know-how, creative thinking, experimentation, and teamwork to design and build high-performance model solar vehicles.
11Solar Car CID What is involved in this CID: Understanding of world issues:Alternative energy sourcesApplication of Physics:AerodynamicsForceMotionTeamworkHow design effects functionProblem solving
12What Teachers are looking out for Highly motivated students who accepts and works on the challenge with excitementStudents thinking on their feet and reacting quicklyPerseverance to complete the task and improve on their carActive participation in a competitive situation
13Group Report In your Report, you are to consider: Social implications: the influence of transportation on social and economic patterns, energy use and the environment.
14Need for Alternative Source of Clean Energy Global WarmingRising Sea levelsFlooding of Coastal regionsOutbreak of diseases
15Objective 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.
16MissionConstruct a car from raw materials that can run on solar energy.Your car should resemble an animal.
17Mission 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.
22TimelineWeeks 1, 2 and 3: Introduction, formation of groups, research and design, report writingWeek 3: submission of group report, building solar carWeeks 4, 5 and 6: Building solar car, modifying and test run of solar carWeek 7: CompetitionWeek 8: Preparation for oral presentationWeek 9: Oral presentationWeek 10: Reflection (Individual report)
24First Task Get into groups of 3. Elect a leader amongst you. Submit the names of group members (and class) to me – indicate the leader.
25Group 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 CarsHow 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?
29Newton’s First LawNewton’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.
30Newton’s 1st law of motion In short,Forces are balanced / Zero Resultant forceObject at rest, v = 0 m s-1Object in motion,v ≠ 0 m s-1Remains at rest, v = 0 m s-1where a = 0 m s-2Remains in motion with same speed & directionwhere a = 0 m s-2
31Newton’s Second LawNewton’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 objectFR = m a
32Horizontal Forces acting on car Horizontal forces influences horizontal motion.Forward driving force from motorFrictional ForceAir Resistance
33Forces acting on a car Resultant force (FR, ) = Mass x acceleration Resultant Force (FR) = Driving Force –(Friction + Air Resistance)Air ResistanceFrictionFrictionDriving Force
34Factors 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.
35Factors 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)
36Factors that increases car’s acceleration The larger the driving forceThe smaller the frictionThe smaller the Air ResistanceThe smaller the mass
37Accomplish MissionsThe 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.
38What 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.
39How 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-conductorsThe 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.
41DopingIn 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.
43Photovoltaic effectThe 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.
45Factors 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.
46Power output against temperature of the solar cells
47Power 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.
48Power 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.
49Parallel 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 APower = 0.5 V x 0.2 A= 0.1 Watt
50Series ConnectionHowever, 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 + V2Vtotal = 0.5 V V= 1.0 VPower = 1.0 V x 0.1 A= 0.1 Watts