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Suntech Contract - PowerPoint

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									                      Solar uses
Great for                        Not so great for
• DC uses (LED lights, DC shop   • Energy hogging appliances
  motors, computers)               (ranges, central AC systems)
• Low to moderate power          • Long distance transport of
  needs                            power
• Remote, off grid needs         • Long term high power use
• Many AC needs (with an           in low sunlight
  inverter
           Solar Cell Structure
• Solar cells are a type of diode.
• Most are made of silicon (Si) that have had
  impurities added to it to help build an
  electrical charge.
• VERY thin and fragile.
        The Race for Efficiency
• The drawback for solar has been cost per watt
  for the consumer.
• Monocrystaline has been the standard for a
  while, slightly more efficient than
  polycrystaline.
             Highest Efficiencies
• Crystalline Silicon
• The highest efficiencies on silicon have been achieved
  on monocrystalline cells. The highest commercial
  efficiency (22%) is produced by SunPower, which uses
  expensive, high-quality silicon wafers. The University of
  New South Wales has achieved 25% efficiency on
  monocrystalline silicon in the lab, technology that has
  been commercialized through its partnership with
  Suntech Power. Crystalline silicon devices are
  approaching the theoretical limiting efficiency of 29%
  and achieve an energy payback period of 1-2 years.
                             Solar power plants
•   The lucky sunny state of Arizona is about to become home to the world’s largest Solar Plant! Thanks to a just-announced
    contract between Abengoa Solar and Arizona Public Service Company (APS), the enormous solar plant called Solana will
    power up to 70,000 homes, and will be the first example in the country of a major utility getting the majority of its energy
    from solar. The 1900 acre plant will be completed by 2011.
Thin-film solar cells
In 2002, the highest reported efficiency for thin film solar cells based on CdTe is
18%, which was achieved by research at Sheffield Hallam University, although this
has not been confirmed by an external test laboratory.
The US national renewable energy research facility NREL achieved an efficiency of
19.9% for the solar cells based on copper indium gallium selenide thin films, also
known as CIGS (also see CIGS solar cells). These CIGS films have been grown by
physical vapour deposition in a three-stage co-evaporation process. In this process
In, Ga and Se are evaporated in the first step; in the second step it is followed by
Cu and Se co-evaporation and in the last step terminated by In, Ga and Se
evaporation again.
Thin film solar has approximately 15% marketshare; the other 85% is crystalline
silicon. Most of the commercial production of thin film solar is CdTe with an
efficiency of 11%.
Typical Residential Application
       Connecting cells in series
• Adds .55 volts with each
  cell
• The amount of amps
  stays constant
• The most common way
  residential panels are
  wired
       Connecting cells in parallel
• Volts stay the same
• Amps increase
• Depending on your
  needs, you can certainly
  mix series and parallel
  wiring, especially if your
  panel is going to be big.
• More common is to
  wire PANELS in parallel,
  rather than individual
  cells
The most common solar layout:
four rows of nine cells in series
     Typical 36-cell panel values
• .55 v per cell
• 21 v DC open current (this is ideal with no
  load)
• Usually 17-18 volts on an average day
• Ideal for charging 12v battery arrays
Soldering on the positive (back)
              side
Drawing a template.
  Field test your runs before
committing them to the panel
            backing
 Adhesives, the secret ingredient.
• Silicone II. Cheap, but may present long-term
  durability problems.
• Ethylene-vinyl acetate. What we’re trying out
  now. Considered more durable in all-weather
  conditions. Used by some solar
  manufacturers.
            The air-free option.
Junction box at the back
  of a panel. To the right
  are a pair of Schrader
  valves. We pumped air
  out of one valve while
  pumping in argon.
The point of an air free
  environment is to
  remove moisture and
  increase efficiency.
FINISHED!
Field Test
Half an amp
reached. We’re
happy! A
multimeter is
essential for
solar, whether
for design or
use.
                       Tips
• If using screws, drill through all three layers at
  once, then number the spacers to sides for
  best fit-up.
• Avoid scratching the surface if using plexi.
• Test each cell before soldering.
• If drilling, use a drill press.
             Tips (continued)
• Sheet metal, glass, and plexi often come in
  8’x4’ dimensions. Three equal pieces will
  make three 70 watt panels. Design for as little
  waste as possible to save money.
• Templates make soldering easier, straighter,
  and for a more attractive finish.
• The less solder used, the better. Most people
  use too much.
              Tips (continued)
• A dull grey solder joint is a bad solder joint.
• Order enough cells to make mistakes.
• Some companies sell broken cells for beginner’s
  practice.
• Silver-bearing solder is preferred by many panel
  builders.
• Pony beads act as spacers between rows of cells and
  relieve stress on the center of the glass.

								
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