BEF Solar Energy Presentation by TplvYo47

VIEWS: 13 PAGES: 34

									   Teaching Solar Energy




SLIDE 1
Energy From the Sun

Students understand that solar radiation is
energy and does work.




SLIDE 2
Solar Energy

• Radiation: Energy transmitted as electromagnetic
  waves or as subatomic particles
• We experience solar energy as light and heat, and
  the simplest way for humans to capture and utilize
  this energy is through passive solar technologies
   » Solar cooking
   » Building design
   » Greenhouses
   » Solar hot water

SLIDE 3
In the Classroom

Demonstration: Global Sun Oven
      » Reaches temperatures in the mid- to upper-300°Fs
      » Exemplifies all the principles of solar cooking


Activity: Students Build Their Own Solar Ovens
      » For younger students there are a number of pre-existing
        solar oven designs
      » Older students can design their own ovens


Other Resources:
      » www.solarcookers.org
      » www.solarcooking.wikia.com
      » www.sunoven.com

SLIDE 4
Assessing Solar Resource

Students understand the concept of solar
resource and that the energy available to
us through solar radiation varies
predictably.




SLIDE 5
Measuring the Sun’s Energy

• Irradiance: the amount of power received from the
  sun over a given area of earth
      » Typically measured in Watts per Square-Meter
• Cumulative Irradiance: the amount of energy that
  hits an area over a certain period of time
      » Typically measured in Watt-Hours per Square-Meter




SLIDE 6
Solar Resource




SLIDE 7
Incident angle




SLIDE 8
Effects of Atmosphere

• The lower the angle of the Sun in the sky, the more atmosphere
  the Sun’s rays must pass through to reach earth and therefore the
  less energy those rays have when they reach earth.




SLIDE 9
The Sun’s Path




SLIDE 10
Solar Irradiance




SLIDE 11
US Solar Resource




SLIDE 12
Shading




SLIDE 13
In the Classroom

Activity: The Reasons for the Seasons
      » The first section in “Teaching Solar” explores the
        concept of solar resource, the predictability of the Sun’s
        position in the sky, and begins to go into sun charts


Activity: Sun Charts
      » On the Solar 4R Schools website, there is a worksheet
        activity available for download


Demonstration or Activity: Solar Pathfinder
      » Using the Solar Pathfinder to do a shading analysis of a
        site




SLIDE 14
The Photovoltaic Effect

Students are familiar with this terminology
and understand that photovoltaic cells
convert energy from the sun into a flow of
electrons.




SLIDE 15
The Photovoltaic Effect

• Definition: The creation of a voltage (or of a corresponding
  current) in a material upon exposure to electromagnetic
  radiation.
      » Exposure to light generates a voltage that produces a continuous
        current flow, which is proportional to the quantity of light that strikes
        the photovoltaic surface.
      » In PV technology, one cell – regardless of size – always generates
        0.5 V; size difference impacts the amount of current generated,
        thereby affecting power production.




SLIDE 16
In the Classroom

Activity: Powering a Load with a Solar Cell
      » Using materials from the SolRun kit, students can wire the 1.5V cells to
        motors with fans, LED lights, small radios or other small loads


Activity: Solar Racing
      » Using the SolRun kit, students can build solar cars


Activity: Testing Voltage and Current with Solar Cells
      » Using multimeters, students can test the voltage and current of the solar
        cells under different light conditions


Other Resources:
      » phet.colorado.edu/en/simulation/photoelectric
      » http://www.pveducation.org/
SLIDE 17
Solar Circuits

Students gain familiarity with photovoltaic
technology and simultaneously reinforce
their knowledge of energy principles.




SLIDE 18
Terms and Definitions

• Voltage (V): electrical potential difference
      • Measured in Volts, voltage is the work required to move a unit of charge
        between two points against an electric field
• Current (I): rate of electrical flow
      • Measured in Amps, current is the amount of electrical charge
        transferred per unit of time
• Power (P): rate at which work is performed
      • Measured in Watts, power is the product of current and voltage;        [P
        = VI ]
• Energy (E): work performed over time
      • Measured in Watt-hours, energy is the ability of a system to do work
        and is the product of power and time; [ E = Pt ]




SLIDE 19
Terms and Definitions (cont.)

• Alternating Current (AC): an electrical current, which periodically
  reverses direction
      • Our electrical grid operates on AC electricity
• Direct Current (DC): an electrical current, which moves in a single
  direction
      • Batteries and photovoltaic (solar-electric) cells both produce DC
        electricity




SLIDE 20
Series Wiring

                • Voltage adds in series
                • Current remains the same.
                • If you lose one load or one
                  source you lose the series.




SLIDE 21
PV Module Series Wiring




SLIDE 22
Parallel Wiring

• Current adds in
  parallel
• Voltage is the same
• If you lose one load
  or one module it
  doesn’t affect the
  others




SLIDE 23
PV Parallel Wiring




SLIDE 24
Series and Parallel Combination




SLIDE 25
In the Classroom

Activity: Wiring Solar Circuits
      » Students can wire together series and parallel circuits using
        the solar cells. Ultimately, these circuits can be built to run
        larger loads.


Activity: Circuit Modeling
      » phet.colorado.edu/en/simulation/circuit-construction-kit-dc
      » LTspice IV (www.linear.com/designtools/software)


Other Resources:
      » Teaching Solar Book & DVD




SLIDE 26
The Photovoltaic System

Students learn about the componentry and
design of a photovoltaic system.




SLIDE 27
Tilt and Orientation Factor (TOF)




SLIDE 28
Total Solar Resource Fraction
(TSRF)

• Total Solar Resource Fraction = percentage of
  the potential solar resource that a photovoltaic
  system is able to harness
• TSRF = (100% - % Shading) x (TOF)
• TSRF = (100% - 5%) x (91%)
• TSRF = 86.45%




SLIDE 29
System Production Data




           Take from PV Watts, a tool developed by NREL
SLIDE 30
Cell => Module => Array



      cell
                     module




             array            String

SLIDE 31
PV System Components




SLIDE 32
In the Classroom

Activity: Designing a Photovoltaic System
      » Using the Pathfinder, an understanding of basic PV system
        componentry and design and the resources below, students can
        design a solar-electric system for their home. Based on their electrical
        bills, they can match expected system production to their
        consumption.


Other Resources:
   » Photovoltaic Systems book
   » PVWatts (mapserve3.nrel.gov/pvwatts_viewer/index.html)
   » pvselect.com
   » System Advisor Model (https://sam.nrel.gov/)



SLIDE 33
Viewing System Production Data




       www.solar4rschools.org


SLIDE 34

								
To top