This document provides an overview of solar energy technologies, including photovoltaics and concentrated solar power. It discusses the basic science behind photovoltaics, describing how silicon is doped to become a semiconductor and how this enables the creation of solar cells. Common types of solar cells and solar panel technologies are outlined. Concentrated solar power technologies like parabolic troughs, power towers, and dish engines are also introduced. Market information is given on solar industry trends, with a focus on Europe, the US, India, and incentives supporting solar development.

1. TECHNOLOGY AND MARKETwww.protekan.comSOLAR ENERGYwww.protekan.com

2. INTRODUCTIONSolar Energy can be defined as the utilization of the sun’s energy for space heating, lighting, water heating and electricity for homes, businesses and industry. www.protekan.com

3. TYPES OF SOLAR ENERGYPhotovoltaicSolar water heatingConcentrated Solar Power (CSP)Others – passive heating and lightingwww.protekan.com

4. PHOTOVOLTAICwww.protekan.com

5. TECHNOLOGYSemiconductor materials can transform solar energy into electricityMost commonly used material for photovoltaic is siliconSilicon by itself is resistant to electric currentProcess called doping makes it receptive to electrical chargeswww.protekan.com

6. SILICON ATOMIC STRUCTUREATOMIC STRUCTURE OF SILICONCRYSTALLINE STRUCTUREContains 3 shells of electrons

7. First two shells having 8 electrons are stable while the third or the outermost shell having 4 electron is unstable

8. Since all silicon atoms are looking for four electrons to become stable , silicon atoms easily bond with each other to form a crystalline structurewww.protekan.com

9. DOPING PROCESSSilicon in its crystalline form is stable and is a poor conductor of electricityWhen materials containing extra electrons or materials lacking electrons are added, the silicon crystal becomes a semiconductor.This process is known as doping.www.protekan.com

10. N-type silicon Materials with 5 electrons in its outer shell (phosphorus) is added

11. Each phosphorus atom displaces a silicon atom – four electrons of phosphorus bonds with silicon atoms

12. One electron is left over and this forms a N type siliconN- type siliconwww.protekan.com

13. P- type siliconMaterials with 3 electrons in its outer shell (boron) is added

14. Each boron atom displaces a silicon atom – three electrons of boron bonds with silicon atoms

15. One gap/hole (lack of electron) is formed and this type is known as the P type siliconP- type siliconwww.protekan.com

16. CREATION OF ELECTRIC FIELDN type and P type silicon are placed against each other – gaps and electrons on either side start reacting to each other

17. Extra electrons in the N type silicon are attracted to the positive nature of the P type – some electrons cross over and create a negative charge on the surface of the p type silicon

18. Similarly the gaps create a positive charge on the surface of the N type siliconELECTRIC FIELDwww.protekan.com

19. UNIDIRECTIONAL FLOW OF ELECTRONSElectrons can now only flow from the P type material to the N type materialIf electrons try to move in the other direction, they get repelled by the negative charge on the surface of the P typeThis forms a solar cellwww.protekan.com

20. ELECTRIC CHARGE – SOLAR ENERGYPhotons pass through the n type material and bumps the electrons in the atom present near the surface of P type materialThe free electrons moves into the n type material since they are attracted by the positive charge near the surface of the N type materialwww.protekan.com

21. ELECTRIC CIRCUITElectrons after moving to the N type material have nowhere to go – N type has extra electrons – cant form any bondMetal conductor strip is placed at the top and bottom of the semiconductor to facilitate the movement of electrons.www.protekan.com

22. BAND GAPSemiconductor material reacts to solar waves within a specific range of wavelengthsThis range is represented by band gapPhotons whose energy is equal to or greater than the band gap can free electronsExcess energy of photon will be converted to heatMaterials with band gaps ranging from 1.1 eV (electron volt) and 1.8 eV are most commonly used for PV, ideal – 1.4 eVSource: www.pvresources.com www.protekan.com

23. TYPES OF PV PANELS - COMMONMonocrystalline siliconMulticrystalline siliconThin film www.protekan.com

24. Monocrystalline siliconCrystalline silicon is usedA silicon boule grown from a single crystal - grown in one planeExpensive than multicrystalline15-18% efficientwww.protekan.com

25. Multicrystalline siliconA silicon boule grown from a multifaceted crystalline material – grown in several plane or directionsLess expensive12-14% efficiencywww.protekan.com

26. Thin filmNo crystalline structure

27. Applied as a thin semiconductor film

28. Amorphous silicon, cadmium telluride, Copper indium diselenide are examples of thin film

29. Low manufacturing cost

30. Versatile

31. Less time consuming to make

32. Efficiency 5-6%www.protekan.com

33. SOLAR WATER HEATINGwww.protekan.com

34. PARTS OF SOLAR WATER HEATING SYSTEMSolar thermal collectorsFluid system to carry the heat from the collector to the point of useOPTIONALPump – to move the fluidTank for storagewww.protekan.com

35. SYSTEM TYPESPassive systemActive systemwww.protekan.com

36. Passive systemRely on gravity to move the liquid from the collector to the storage tankTendency of water to circulate as it is heatedwww.protekan.com

37. Active systemRely on pump to move the fluid from the collector to the storage tankThe storage tank is usually well insulatedwww.protekan.com

38. TYPES OF SOLAR THERMAL COLLECTORSFlat plate collectorEvacuated tube collectorwww.protekan.com

39. Flat plate collectorMounted on roofConsists of thin flat rectangular box with a transparent cover facing the sunTubes run through the box- carry the fluid and is connected to an absorber plateAbsorber plate is painted black to absorb the heatwww.protekan.com

40. Evacuated tube collectorEach evacuated tube consists of glass tubes and absorber tubes and are aligned parallel to one anotherSunlight passes through the glass tube and heats the absorber tubeTop of the tubes are sealedAbsorber tube is sealed in vacuum – for insulationwww.protekan.com

41. CONCENTRATED SOLAR POWERwww.protekan.com

42. TYPES OF CSPParabolic troughLinear FresnelDish engineSolar chimneySolar power towerConcentrated photovoltaicwww.protekan.com

43. Parabolic troughConsists of a linear parabolic reflectorConcentrates solar energy onto a receiver positioned at the reflector’s focal pointTracking mechanism is usedWorking fluid is heated as it flows through the receiver and is used as a heat source at the power generating systemSource: www.energylan.scandia.govwww.protekan.com

44. Linear FresnelUses mirror strips instead of parabolic mirrors to concentrate sunlight onto the receiver carrying the working fluidCheaper than using parabolic mirrorsSource: www.energylan.scandia.govwww.protekan.com

45. Dish EngineConsists of parabolic reflectorsConcentrates sunlight onto the receiver positioned at the reflector’s focal pointThe reflector tracks the sunUses stirling engine to generate powerwww.protekan.com

46. SOLAR CHIMNEYConsists of a large transparent room (greenhouse)Sloped to a hollow tower or chimneyThe sun heats the air in the greenhouse structure which rises up the chimney – drives the air turbinewww.protekan.com

47. SOLAR POWER TOWERTracking reflectors (heliostats) concentrates sunlight onto a central receiver positioned at the top of a towerThe receiver contains the working fluid (sea water) which becomes heatedHeat source is used for power generation and energy storagewww.protekan.com

48. CONCENTRATED PVTracking mechanism is usedReflectors directs the sunlight onto a PV surface positioned at the focal point of the reflectorwww.protekan.com

49. PHOTOVOLTAICMARKET OVERVIEWwww.protekan.com