Transcript Photovoltaic Solar System Components

PV System Components
Advanced Engineering
The Technology Academy @
Landstown High School
What is a solar cell?
• Solid state device that converts solar energy
directly into electrical energy
• Efficiencies from 10%- 80%%
• No moving parts
• No noise
• Lifetimes of 20-30 years or more
Cross Section of Solar Cell
How Does It Work?
• The junction of dissimilar materials (n (+) and p () type silicon) creates a voltage,
• Energy from sunlight knocks out electrons,
creating a electron,
• Connecting both sides to an external circuit
causes current to flow,
• In essence, sunlight on a solar cell creates a small
battery with voltages typically 0.5 volt DC,
Combining Solar Cells
• Solar cells can be electrically connected in series
(voltages add) or in parallel (currents add) to give
any desired voltage and current,
• Power (Watts) output is calculated P = I x V
• Photovoltaic cells are typically sold in modules (or
panels) of 12 volts with power outputs of 50 to
100+ watts.
• These are then combined into arrays to give the
total desired power or watts.
Cells, Modules, Arrays
Other System Components
While a major component and cost of a PV system is
the array, several other components are typically
needed. These include:
• The inverter – DC to AC electricity
• DC and AC safety switches
• Batteries (optional depending on design)
• Monitor – (optional but a good idea)
• Ordinary electrical meters work as net meters
The Photovoltaic Array with its
other electrical components
PV was developed for the space
program in the 1960’s
PV Price and Quantity
Manufactured Relationship
The PV Market
Solar Calculators
REMOTE POWER
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Lighting
Buoys
Communications
Signs
Water Pumping
Mountain Cabins
Photovoltaic Array for Lighting
Telecommunications Tower
Remote Water Pumping in Utah
Recreation Vehicle Outfitted with
Solar Panels
Solar Lanterns for Landscaping
A Solar Driven Band
The PV Market
• As prices dropped, PV began to be used for standalone home power.
• If you didn’t have an existing electrical line close
to your property, it was cheaper to have a PV
system (including batteries and a backup
generator) than to connect to the grid.
• As technology advanced, grid-connected PV with
net metering became possible.
NET METERING
• In net metering, when the PV system produces excess
electricity, it is sent to the grid system, turning the meter
backwards.
• If you are using more power than is being produced, or it is
at night, the electricity is received from the grid system and
the meter turns forwards.
• Depending on PV size and electrical consumption, you
may produce more or less than you actually use.
• Individual houses may become power producers.
Net Metering can be done with or
without a battery backup
BATTERIES
• Batteries can be used to provide long-term or
short-term electrical supply in case of grid failure.
• Many grid-connected houses choose to have a
small electrical battery system to provide loads
with power for half a day in case of outage.
• Larger number of batteries are typically used for
remote grid-independent systems.
2 KW PV on Roof with battery
storage. Solar hot water
collectors and tank
PV On Homes
• PV can be added to existing roofs.
• While south tilted exposure is best, flat roofs do
very well.
• Even east or west facing roofs that do not have
steep slopes can work fairly well if you are doing
net metering since the summer sun is so much
higher and more intense than the winter sun.
• The exact performance of any PV system in any
orientation is easily predictable.
Photovoltaic Array on Roof and
as an Overhang
½ KW PV System Installed
along Roof Ridge
California Home PV Installation
PV on House
2.4 KW System under
Installation in New Hampshire
PV Installed at Roofline on
Building at Frost Valley, NY
PV Panels on Tile Roofs in
Arizona
PV on Roof in California
Other Mounting Systems?
• If it is impossible or you don’t want to put a PV
system on your existing roof, it is possible to pole
mount the arrays somewhere near the house as
long as the solar exposure is good.
• Pole mounted solar arrays also have the potential
to rotate to follow the sun over the day by
installing a sun tracking system,
• Sun tracking systems can provides a 30% or more
boost to the PV system performance.
Pole Mount for Solarex Modules
Pole Mounted PV
Pole Mounted PV
Roof Integrated PV
• If you are doing new construction or a
reroofing job, it is possible to make the roof
itself a solar PV collector.
• This saves the cost of the roof itself, and
offers a more aesthetic design.
• The new roof can be shingled or look like
metal roofing. A few examples follow.
Solar Roofing Shingles
Roof Integrated Photovoltaics in
Misawi, Japan
Roof Integrated PV in Japan
Roof Integrated PV in Maine
Roof Integrated Photovoltaic
System in Colorado
Roof Integrated PV
(objects below chimney are solar hot water collectors)
PV Installation in Planned
Community in Germany