Solar Energy Technology Science Summer Camp

1. Solar Energy TechnologyScience Summer Camp Session 2 Monday 12:30 - 3:00 PM Site Selections Factors 1

2. Session 2 Topics • Solar Radiation and Geometry (as part of a site assessment). • Basic Definitions • Son - Earth Relationships • Solar angle effect on irradiance • True vs. magnetic north and south • Solar Charts and diagrams 2

3. Basic Definitions Radiation Basic solar terms • Radiance - the amount of radiation leaving or arriving at a point on a surface • Radiation - the process in which energy travels through a medium or through space • Irradiance - the rate of light energy striking a given area of surface in a given amount of time • Types of irradiance: Global, Direct and Diffuse • Irradiation - the amount of solar energy that falls on the surface over time is called irradiation. This is the ENERGY density of solar radiation. It is measured in kilowatt-hours/square meter/day • Langley, a unit of solar radiation; equal to one calorie per square centimeter. 3 Activity 2-1 In: Use Flashlight to Trace Terms 12:35 PM

4. Conversions • Example: Convert 1000 Langleys per day to kWh/m2/day • 1000 Ly/day (0.003155 kWh/m2/Ly) = 3.155 kWh/m2/Ly/day 12:37 PM

5. Earth - Sun Relationships • Sun Angle has a significant effect on the irradiance reaching a solar array • Higher angle more solar energy reaches array • Seasonal differences • Diurnal (daily) changes • Earth Orbit (year) versus Earth Rotation (day) • 365.25 rotations per one orbit around sun • Tilt of earth on axis and Orbit cause of Seasons • Note: sun farther away during NH summer • We will Experiment with globe and flashlight

6. Orbit and Tilt the Cause of the Seasons Sun’s Path Reference 4

7. Seasons and Distance From Sun

8. Position of sun changes during year Earth’s travel around the Sun as seen back here on Earth Reference 2

9. Rotation Cause of the Day-Night Cycle

10. Azimuth Angle – Angle of Sun’s east-west position. 90 180 Reference 4 12:45 PM Activity 2-2 In : Use Flashlight to Illustrate Solar Angle on globe by time of day and season

11. Peak Sun Hours Reference 4

12. 0 Atm ~1.5 Atm

13. Factors that Affect Surface Irradiance • Solar Angle: • Experiment that measures of solar angle changes and irradiance values • Use solar car to discover relationship of position of the sun to the power generated by solar panels. • Atmospheric conditions: • Clouds, Haze, Dusts, Humidity, Temperature • Temperature impact on solar performance cool panel with dry ice then warm up see degradation of performance. • Shading: • Determine effect of horizon on solar irradiation (shading) • Shading will cause disproportionate degradation of performance • Irradiation effects of various surfaces • Darker more absorbed • Temperature impact on solar performancecooler more

14. Factors affecting solar radiation • Angle of incident • Clouds • Snow, Rain, Fog, etc. • Dust particles • Air pollution • Reflective materials

15. Result of FactorsUSSolar Energy Distribution Reference 3 12:55 PM

16. Global Declination Field Global Declination Field is the difference of true frommagneticnorth

17. Magnetic vs. True North Pole True Mag N Magnetic North changeswith time Daily Movement ~53 mi 1000 km (600 mi) last 100 years http://gsc.nrcan.gc.ca/geomag/nmp/long_mvt_nmp_e.php

18. Correction for Mag to True North

19. Where is “Truth South”? http://www.magnetic-declination.com/ • Must correct compass reading based on magnetic declination • About 13.5degrees to the west of 0 correction in the Utica area (-13.5) • True = compass + declination • To correct for Utica = compass - 13.5 Historic Changes of Declination:http://www.ngdc.noaa.gov/geomagmodels/USHistoric.jsp

20. Declination Calculationhttp://www.ngdc.noaa.gov/geomag/ Activity 2-3 In: Demo of finding declination angle using online calculator. Declination calculator:http://www.ngdc.noaa.gov/geomagmodels/Declination.jsp 1:05 PM Activity 2-4 In: Now Demo of finding True North using Compass and Without compass.

21. Finding True North with a Compass • Online Link • Must correct compass reading based on magnetic declination • About 13.5˚ to the west of 0 correction in the Utica area (-13.5˚) • True = compass + declination • To correct for Utica: True North = Compass N - 13.5˚ • 360˚ Compass Mag N = True North 346.5˚ • 60˚ Compass Mag = True 46.5˚ • 10˚ Compass Mag = True 355.5˚ • Note if answer is negative add 360˚ • 10˚ - 14.5˚ + 360˚ = - 4.5˚ + 360˚ = 356.5˚ N

22. Finding True North Without a Compass • Method 1 • At solar noon find the shadow of a straight up and down stick - it will point due north • Solar noon:http://www.esrl.noaa.gov/gmd/grad/solcalc/ • Method 2 http://www.wikihow.com/Find-True-North-Without-a-Compass • Place a stick upright in the ground so that you can see its shadow. • Mark the tip of the shadow with a small object, such as a pebble, or a distinct scratch in the ground. • Wait 10-15 minutes. Mark the new position of the shadow's end. The shadow tip will move mostly from west to east in a curved line. • Draw a straight line in the ground between the two marks. This is an approximate east-west line. • Other Methods • Watch - Point the hour hand at the sun. N is ½ distance to 12 • Stars - Locate the North Star (Polaris) in the night sky. The North Star is the last star in the handle of the Little Dipper constellation. If you have trouble finding it, find the Big Dipper. The two lowest stars in the Big Dipper (the outermost stars of the cup of the dipper) form a straight line that "points" to the North Star. N

23. 12 9 3 6 Watch Method True N

24. Be Careful! Inconsistency in PV industry Compass Bearings are not the same as Azimuth Angles 1:10 PM Reprinted from “Photovoltaic Systems, Jim Dunlop and Todd Stafford, ATP Publication, 2007”

25. Site AssessmentHow Much Sun? Altitude Angle – Angle of Sun above the horizon • Theoretical Max Irradiance based upon clear sky is a function of latitude • Actual Irradiance is a function of: • (1)Cloudiness and other atmospheric conditions • (2) Shading (3) Roof pitch and orientation from south Sun Angle

26. Site AssessmentShading Issues Sun - Radiant Energy Cloud

27. Solar Path - Sun Chart Diagram Activity 2-5 In: Predict solar position using solar path diagrams Given time of day and time of year find solar elevation angle http://solardat.uoregon.edu/SunChartProgram.html

28. Sun Chart Diagrams and Shading http://solardat.uoregon.edu/SunChartProgram.html

29. Solar Pathfinder Activity 2-6 In: Demonstrate use of Solar Pathfinder For Shade Analysis A good way to analyze the sun’s path across a surface is using a Solar Pathfinder Solar Pathfinder Home Solar Pathfinder Video Note show 5 min video at end of class

30. Pathfinder Solar Chart

31. Shading Analysis Solar Pathfinder and Shading Analysis

32. Shading AnalysisNickerson House Example Roof slope = 30 degrees

33. Shading Analysis Nickerson Solar Pathfinder

34. Pathfinder Exercise Solar Chart

35. Nickerson Shading Analysis Max Solar Fraction 0.88 means 12% lost due to shading

36. Additional Information Information needed in addition to Solar Pathfinder for Shading Analysis 1. PV system size (Ex. 5.96 kW) 2. Solar Radiation Data (Peak Sun Hours) From Location (Lat/Lon) 3. Orientation - Magnetic Declination (Ex -14.5˚) 4. Roof Slope (5 :12) for Tilt of Collector 1:20 PM

37. Roof Pitch to Roof Angles In NY 6 inches in 12 inches is good Chart for Conversion of Roof Pitch to Roof Angles Tan Angle = Rise/Run Sin Angel = Rise/Hyp Y = Rise Angle X = Run Note: Solar Cell = 4.3 " So multiply by rise 2.79 to use table Rise/Run converters: http://blocklayer.mobi/riserun.aspx http://www.1728.com/gradient.htm http://www.1728.com/distance.htm

38. Rise/Run - Angle Table % rise / run = rise/run x 100% How to use: Measure your rise over run Multiply by 100 Go to the % rise / run Interpolate and Estimate Angle Example: % rise/run = 6/12 x 100% = 50% 50% is between 46.6 and 57.7 Halfway would be 27.5 deg It is a little closer to 46.6 so ~27 deg

39. Energy Production Adjustments for Orientation and Tilt Angle Reference 4 150˚ 230˚ 180˚ Annual Solar Irradiation (kWh/m2) in Berlin as function of azimuth (x) and tilt angle (y)

40. Energy Production Adjustments for Orientation and Tilt Angle

41. Nickerson Power Analysis - All Factors

42. Solar Pathfinder Activity 2-6 In: Demonstrate use of Solar Pathfinder For Shade Analysis A good way to analyze the sun’s path across a surface is using a Solar Pathfinder Solar Pathfinder Home Solar Pathfinder Video 1:25 PM

43. Outside Activities1:35 - 3:00 PM • Break into 3 - 6 groups - (Select someone to present results) • Activity 2-1 Out 1:35 - 1:45 PM: Measure True North (Glenn & Vince): • - Using compass (on the path finders) • - Watch (Use handout) • - Measurement with stick procedures. (Need ski poles and rock markers) - Note initial at 12:20 PM • Activity 2-5 Out 1:45 - 2:10 PM: Solar Pathfinder Exercise (Vince) • - Prepare hand drawn pathfinder solar path diagram – discuss shading analysis - (More Wed or Thur) • Activity 2-2 Out 2:10 - 2:55 PM: Solar Angle: Experiment with solar angle changes and irradiance impact • - Use solar car to discover relationship of position of the PV panel with respect to the sun to the power generated by solar panels. • - Race cars - calculate speed over course • - Variation: (1) Tilt Angle (2) Orientation to Sun (3) Impact of Shading • Activity 2-3 2:45 - 3:00 PM Out: Impact of Atmospheric Conditions: Clouds, Haze, Dusts, and Tree Shading • - Shade cells observe changes - degradation of performance of cars/fans etc.

44. Inside Activities • Break up into 3 groups - (Select someone to present results) • Inside: • Activity 2-1-in: Use Flashlight to Trace Terms Basic solar terms • Activity 2-2 in: Use Flashlight to Illustrate Angle • Effect of sun's angle on irradiance (solar power) • - Seasonal differences and Diurnal changes • - Experiment with globe and flashlight • Activity 2-3 in: Materials: need globe or large beach balls, basket balls good • Predict solar position using solar path diagrams • Activity 2-4 in: Go over use of Solar Pathfinder or sun charts • Experiment with pathfinder

45. Outside Activities • Break into 3 groups - (Select someone to present results) • Activity 2-1 Out: Measure True North (Glenn & Vince): • - Using compass (on the path finders) • - Watch (Use handout) • - Measurement with stick procedures. (Need ski poles) • Activity 2-2 Out: Solar Angle: Experiment with solar angle changes and irradiance values/impact • - Use solar car to discover relationship of position of the PV panel with respect to the sun to the power generated by solar panels. • - Race cars - calculate speed over course • Activity 2-3 Out: Impact of Atmospheric Conditions: Clouds, Haze, Dusts, and Tree Shading • - Shade cells observe changes - degradation of performance of cars/fans etc. • Activity 2-4 Out: Temperature impact on solar performance (May not be able to do this) • - cool panel with dry ice then warm up. See degradation of performance with higher temperature. • Activity 2-5 Out: Solar Pathfinder Exercise (Vince) • - Prepare hand drawn pathfinder solar path diagram – discuss shading analysis • Activity 2-6 Out: Calculate Potential Electrical Energy Production • - Using Roof Slopes • Group 1 Slope is 0 degrees (horizontal PV module), • Group 2 Slope is 6:12 • Group 3 Slope is 10:12. Group 4 : Slope is 57 degrees from the horizon • - Calculate Shading Percentages, Daily Peak Sun-Hours, Monthly Power Production (DC kWh) and Annual Energy Production (kWh) • Activity 2-7 Out: Project: Graphing Heat Absorption • Activity 2-8 Out: Heat absorbing capacity of different colors and backgrounds • Activity 2-9 Out: Radiant water heat loss experiment