Skip to main content Skip to navigation Home Main menu * Home * Courses * Instructions * Contact * Login You are hereHome Welcome to PVCDROM 2. Properties of Sunlight

Declination Angle Solar Time ElevationAngle The declination angle, denoted by , varies seasonally due to the tiltof the Earth on its axis of rotation and the rotation of the Eartharound the sun. If the Earth were not tilted on its axis of rotation,the declination would always be 0. However, the Earth is tilted by23.45 and the declination angle varies plus or minus this amount. Onlyat the spring and fall equinoxes is the declination angle equal to 0.The rotation of the Earth around the sun and the change in thedeclination angle is shown in the animation below.Animation showing how the tilt angle changes from the summer solstice inthe northern hemisphere (or winter in the southern hemisphere) to thenorthern hemisphere winter solstice (summer in the south).The declination of the sun is the angle between the equator and a linedrawn from the centre of the Earth to the centre of the sun. Theseasonal variation of the declination angle is shown in the animation below. Despite the fact that the Earth revolves around the sun, it is simplerto think of the sun revolving around a stationary Earth. This requires acoordinate transformation. Under this alternative coordinate system, thesun moves around the Earth.The declination angle can be calculated by the equation [1]:where d is the day of the year with Jan 1 as d = 1. A more accurateexpression is:The declination is zero at the equinoxes (March 22 and September 22),positive during the northern hemisphere summer and negative during thenorthern hemisphere winter. The declination reaches a maximum of 23.45on June 22 (summer solstice in the northern hemisphere) and a minimum of-23.45 on December 22 (winter solstice in the northern hemisphere). * 1. Cooper PI . The absorption of radiation in solar stills . Solar Energy [Internet]. 1969 ;12:333 - 346. Available from: http://www.sciencedirect.com/science/article/B6V50-497BD6C-27/2/a4ca2069fe8c8b0cfa571de016d93cc5 Solar Time ElevationAngle * Log in or register to post commentslogoPVCDROM*Christiana Honsbergand Stuart Bowden * * Instructions * 1. Introduction o Solar Energy o Introduction o The Greenhouse Effect * 2. Properties of Sunlight o 2.1. Basics of Light o Properties of Light o Energy of Photon o Photon Flux o Spectral Irradiance o Radiant Power Density o 2.2. Blackbody Radiation o Blackbody Radiation o 2.3. Solar Radiation o The Sun o Solar Radiation in Space o Solar Radiation Outside the Earth's Atmosphere o 2.4. Terrestrial Solar Radiation o Solar Radiation at the Earth's Surface o Atmospheric Effects o Air Mass o Motion of the Sun o Solar Time o Declination Angle o Elevation Angle o Azimuth Angle o The Sun's Position o Sun Position Calculator o Sun's Position to High Accuracy o Solar Radiation on a Tilted Surface o Arbitrary Orientation and Tilt o Calculation of Solar Insolation o 2.5. Solar Radiation Data o Measurement of Solar Radiation o Analysis of Solar Irradiance Data Sets o Typical Meteorological Year Data (TMY) o Making Use of TMY Data o Average Solar Radiation o Isoflux Contour Plots o Sunshine Hour Data o Cloud Cover Data * 3. PN Junction o Introduction o 3.1. Basics o Semiconductor Materials o Semiconductor Structure o Conduction in Semiconductors o Band Gap o Intrinsic Carrier Concentration o Doping o Equilibrium Carrier Concentration o 3.2. Generation o Absorption of Light o Absorption Coefficient o Absorption Depth o Generation Rate o 3.3. Recombination o Types of Recombination o Lifetime o Diffusion Length o Surface Recombination o 3.4. Carrier Transport o Movement of Carriers in Semiconductors o Diffusion o Drift o 3.5. P-n Junctions o Formation of a PN-Junction o P-N Junction Diodes o Bias of PN Junctions o Diode Equation o 3.6. Diode Equations for PV o Ideal Diode Equation Derivation o Basic Equations o Applying the Basic Equations to a PN Junction o Solving for Depletion Region o Solving for Quasi Neutral Regions o Finding Total Current o Eg1: Wide Base Diode o Eg2: Narrow Base Diode o Summary o Chapter 3 Quiz * 4. Solar Cell Operation o 4.1. Ideal Solar Cells o Solar Cell Structure o Light Generated Current o Collection Probability o Quantum Efficiency o Spectral Response o The Photovoltaic Effect o 4.2. Solar Cell Parameters o IV Curve o Short-Circuit Current o Open-Circuit Voltage o Fill Factor o Efficiency o Detailed Balance o Tandem Cells o 4.3. Resistive Effects o Characteristic Resistance o Effect of Parasitic Resistances o Series Resistance o Shunt Resistance o 4.4. Other Effects o Impact of Both Series and Shunt Resistance o Effect of Temperature o Effect of Light Intensity o Ideality Factor o Chapter 4 Quiz * 5. Design of Silicon Cells o Solar Cell Design Principles o 5.1. Optical Properties o Optical Losses o Anti-Reflection Coatings o AR Coating Color o DLARC o Surface Texturing o Material Thickness o Light Trapping o Lambertian Rear Reflectors o 5.2. Reducing Recombination o Recombination Losses o Current Losses Due to Recombination o Voltage Losses due to Recombination o Surface Recombination o 5.3. Top Contact Design o Series Resistance o Base Resistance o Sheet Resistivity o Emitter Resistance o Contact Resistance o Finger Resistance o Optimization of Finger Spacing o Metal Grid Pattern o 5.4. Solar Cell Structure o Silicon Solar Cell Parameters o Efficiency and Solar Cell Cost o Chapter 5 Quiz * 6. Manufacturing Si Cells o First Photovoltaic devices o Early Silicon Cells o 6.1. Silicon Wfers & Substrates o Refining Silicon o Types Of Silicon o Single Crystalline Silicon o Czochralski Silicon o Float Zone Silicon o Multi Crystalline Silicon o Wafer Slicing o Other Wafering Techniques o 6.2. Processing Technologies o Solid State Diffusion o 6.3. Cell Fabrication Technologies o Screen Printed Solar Cells o Buried Contact Solar Cells o High Efficiency Solar Cells o Rear Contact Solar Cells o 6.4. Solar Cell Production Line o Introduction o Source Material o Growing Ingots o Sawing the Ingot into Bricks o Wafer Slicing o Texturing o Emitter Diffusion o Edge Isolation o Anti Reflection Coatings o Screen Print Front o Screen Print Rear Aluminium o Screen Print Rear Silver o Firing o Testing o Module * 7. Modules and Arrays o Introduction o 7.1. Module Design o Module Structure o Module Materials o Packing Density o 7.2. Interconnection Effects o Module Circuit Design o Mismatch Effects o Mismatch for Cells Connected in Series o Shading o Hot Spot Heating o Bypass Diodes o Mismatch for Cells Connected in Parallel o Mismatch Effects in Arrays o 7.3. Temperature Effects o PV Module Temperature o Heat Generation in PV Modules o Heat Loss in PV Modules o Nominal Operating Cell Temperature o Thermal Expansion and Thermal Stresses o 7.4. Other Considerations o Electrical and Mechanical Insulation o 7.5. Lifetime of PV Modules o Degradation and Failure Modes * 8. Characterization o Introduction o 8.1. Measurement of Cell Efficiency o Measurement of Solar Cell Efficiency o Illumination Sources o Temperature Control o Electronics o Probing o 8.2. Other IV Measurements o Dark IV Measurements o Jsc-Voc and Suns-Voc o 8.3. IV Characterization o Measurement of Series Resistance o Double Diode Model o Measuring Ideality Factor o 8.4. Optical Characterization o Reflectance o Spectral Response o Laser Beam Induced Current o 8.5. Lifetime o Carrier Lifetime o Bulk Lifetime o Surface Recombination o Transient Measurements o Quasi-Steady-State Lifetime Measurements o General Lifetime Measurements o Effect of Trapping on Lifetime Measurements o 8.6. Luminescence o Electroluminescence o 8.7. Simulation o Introduction to Simulation o PC1D o Tandem Calculations o 2D Modeling o SEM and EBIC o Four Point Probe Resistivity Measurements * 9. Material Properties o General Properties of Silicon o Optical Properties of Silicon o Bi2S3 o CdS o CdSe o CuO o FeS2 o Mg2Si o SnS o ZnSe o CuInSe2 o CuS o MnS o TiS2 * 11. Appendices o Solar Cell Efficiency Records o Standard Solar Spectra o Periodic Table o Units and Conversions o Physical Constants o Equations for Photovoltaics * Korean Version * List of: o Equations o Flash Animations o Interactive Graphs o References Search formSearch [ + ] FeedbackIf you experience a bug or would like to see an addition on the currentpage, feel free to leave us a message.Message *By submitting this form, you accept the Mollom privacy policy.