Tuesday, May 15, 2012


BUY GREEN ENERGY SAVE MONEY ON YOUR ENERGY BILLS   Do it yourself solar panels easy and go green
1. Photovoltaic (fo-to-vol-ta-ik) systems are solar systems that produce
electricity directly from sunlight. The term "photo" comes from the Greek
"phos," meaning light. "Voltaic" is named for Alessandro Volta (1745-1827), a
pioneer in the study of electricity for whom the term "volt" was named.
Photovoltaics, then, means "light electricity." Photovoltaic systems produce
clean, reliable electricity without consuming any fossil fuels. They are being
used in a wide variety of applications, from providing power for watches,
highway signs, and space stations, to providing for a household's electrical
2. What is the difference between "solar energy" and
"photovoltaics?"Photovoltaics is one form of solar energy. The
term solar energy can refer to something as simple the energy gathered in your
parked, sealed car (your solar collector) and converted into heat. Solar energy
is often used to heat houses directly through passive means (sun enters window,
room warms). Solar energy is also often used to heat water (a solar collector is
mounted in direct sunlight, which warms a heat transfer fluid, which in turn
heats the water in your hot water tank).Photovoltaics refers
specifically to the practice of converting the sun's energy directly into
electricity using photovoltaic cells. Photovoltaic cells are often referred to
as PV cells or solar cells.
3. What is solar thermal
energy?Solar thermal energy refers to harnessing the sun's
light to produce heat. Heat results when photons, packets of light energy,
strike the atoms composing a substance (water, your body, asphalt), exciting
them. Solar thermal technologies include passive solar systems for heating (or
cooling!) buildings; flat plate solar collectors, often used for providing
households with hot water; and solar concentrator power systems. These systems
also known as solar thermal power plants, use the sun's heat to create steam,
which then turns a turbine and produces electricity. (Fossil fuel burning power
plants also produce electricity by first creating steam in order to turn a
4. Can I heat my house with
photovoltaics? Using electricity to heat a house, as anyone who
uses electric heat and pays monthly bills to the utility knows, is very
inefficient and costly. Theoretically, one could heat one's home with
photovoltaics (electricity is electricity, whether it comes from PV panels or
from a coal burning power plant). Practically, though, this would be costly, as
producing electricity from a PV system is more expensive than purchasing it from
the utility. One can, however, heat one's house very effectively and cheaply by
harnessing the sun's energy in other ways.
5. What are the components of a PV system?
Photovoltaic Cell -- Thin squares, discs, or films of semiconductor material
that generate voltage and current when exposed to sunlight.
Module -- Photovoltaic cells wired together and laminated between a clear
superstrate (glazing) and encapsulating substrate.
Array -- One or more modules with mounting hardware and wired together at a
specific voltage.
Charge Controller -- Power conditioning equipment to regulate battery
Battery Storage -- A medium that stores direct current (DC) electrical
Inverter -- An electrical device that changes direct current to alternating
current (AC) to operate loads that require alternating current.
DC Loads -- Appliances, motors and equipment powered by direct current.
AC Loads -- Appliances, motors and equipment powered by alternating
6. How do the panels work? A solar
panel (module) is made up a number of solar cells. Solar cells are generally
made from thin wafers of silicon, the second most abundant substance on earth,
the same substance that makes up sand. To make the wafers, the silicon is heated
to extreme temperatures, and chemicals, usually boron and phosphorous, are
added. The addition of these chemicals makes the silicon atoms unstable (their
electrons less tightly held). When photons of sunlight hit a solar panel, some
are absorbed into the solar cells, where their energy knocks loose some of the
modified silicon's electrons. These loose electrons are forced by electric
fields in the PV panel to flow along wires that have been placed within the
cells. This flow of electrons through the wires is electricity, and will provide
power for whatever load we attach (a calculator, a light bulb, a satellite,
etc.) Because solar cells are modular, a system's size can be increased
(or decreased) over time, according to need.
7. Are there any applications for photovoltaics where I don't need
batteries? The simplest and least expensive PV systems are
designed for day use only. These systems consist of modules wired directly to a
DC appliance, with no storage device. When the sun shines on the modules, the
electricity generated is used directly by the appliance. Higher insolation
(sunshine) levels result in increased power output and greater load capacity.
And when the sun stops shining, your appliance stops working. These
simple systems are an appropriate, cost-effective option for loads operated only
during the daytime. Examples of day use systems include: Remote water
pumping with a storage tank. Operation of fans, blowers, or circulators to
distribute thermal energy during the day for solar water heating systems or
ventilation systems. Stand-alone, solar-powered appliances such as
calculators and toys. It is also possible, in a utility grid
interconnected system (see below), to do without batteries, as such a system is
essentially using the grid as its storage device.
8. What if I want electricity at night or on cloudy days? Introducing
batteries to a PV system allows electricity to be stored when the sun is
shining. This electricity can then be used to provide power after the sun goes
9. What is a utility grid interconnected system? Utility-connected systems, also called "grid-connected" or "grid-tied" systems, are for homes or commercial buildings that are connected to
an electric utility. They are designed to provide a modest part to all of the
building's total electricity needs. Advances in solar power electronics make it
relatively easy to connect a solar electric system to the utility. Energy
generated by such a system is first used within the home, and surplus power is
"pushed" onto the utility's wires. In many states of the U.S., local utilities
have "net-metering," which allows a homeowner's meter to spin backwards when his
or her electricity is pushed back onto the grid. When this happens, the utility
buys electricity from the homeowner, instead of the other way around! (And the
utility pays the homeowner for the retail value of the electricity. Without
net-metering, the utility would be forced by law to buy electricity from the
homeowner, (an independent producer), at wholesale.) A draw-back of
connecting your PV system to the grid (and using the grid as "storage") is that
when your area suffers a power outage, your PV system automatically shuts off.
(This is done intentionally, in order to protect people working on the lines
from live electricity.) To avoid this problem, many people introduce batteries
to their grid-tied system, which provide power in the event of a utility power
10. How many PV panels do I need for my house? This depends on how much electricity you use in your home, and where your house is located. The average American household uses 600
Kilowatt-hours of electricity per month. However, an energy efficient home may
use only half that. In a sunny climate, a 2 kilowatt PV system can produce 300
kilowatt-hours of electricity per month. (To generate 2 kilowatts of power you
need about 240 square feet of solar panels.) Therefore, the first step in
planning a solar system is reducing electricity consumption. It is always more
cost-effective to invest in energy efficiency than to install a larger PV
system. Planning, mindfulness and some initial investment can result in a
dramatic reduction in electricity use, without sacrificing the comforts to which
we've become accustomed. As SEI alum Cari Spring says in her book When the Light
Goes On: "You don't have to sit in a dark, cold room to save
11. How can I conserve energy? Electricity? It is critical that heating and cooling systems,
(which account for 40% of the energy budget of the average American household),
be highly efficient. Electric heaters and air conditioners are tremendous energy
hogs; fortunately, more efficient options abound. In addition, it is important
that once your house feels comfortable to you, it stays that way--good
insulation is crucial. (Preventing air leakage by caulking and sealing is the
most cost-effective way of reducing heating and cooling costs.) A
household can save electricity a number of ways, including: purchasing energy
efficient appliances and fixtures (e.g. compact fluorescent lights); using solar
thermal energy (e.g. drying clothes in the sun, using a solar hot water system)
investing in propane or natural gas-powered major appliances (such as
refrigerators, stoves, and clothes dryers); and cutting back on appliance use
(e.g. turning off lights, abandoning the electric can opener).For more
ideas (including a list of top-rated, energy efficient appliances, cars, and
12. What is solar cooking? Solar cookers use no electricity or gas, require no
fire wood, and produce no air pollution. The simplest type of solar cooker is a
box cooker: an insulated box painted black on the inside and covered with glass
or plastic. Sunlight enters the box and heats the food inside. Reflectors can be
added to increase the solar insolation captured. An inexpensive cooker can be
made out of cardboard, crumpled-up newspaper for insulation, and aluminum foil
for reflectors, and can reach temperatures over 250° F. Higher-quality cookers
can reach temperatures of up to 425° F. In many countries of the world,
burning wood and animal dung for cooking is wreaking havoc on the environment:
contributing to deforestation, desertification, air pollution, and global
warming. In addition, cooking over smoky fires contributes to respiratory
illnesses, and in many parts of the world, women and children spend over half
their waking hours gathering firewood (which, in many places, is becoming more
and more scarce). Besides ameliorating these problems, solar cookers can also be
used to purify drinking water, sanitize medical instruments, and heat water for
laundry. Their potential for bettering lives is tremendous. And, in this
country, cooking outside in a solar cooker can dramatically reduce your home
cooling bills in the summer!
13. What can be cooked in a solar oven? Anything you can cook in a conventional oven--the
limit is your imagination. Dishes often require less water when cooked in a
solar oven, as well as less salt and sugar (due to the gentle cooking process).
Just remember to use a dark colored pot, and use potholders! Solar ovens get
14. Are there solar energy power plants? Yes. Many utility companies have recently installed
large photovoltaic arrays to provide consumers with solar generated electricity
or as backup systems for "critical" equipment. Solar thermal power plants
produce electricity more cheaply than photovoltaic plants, at least in regions
where there is little to no cloud cover. (Solar thermal systems need direct
sunlight; photovoltaic systems will still function in cloudy conditions, though
their output is diminished.) The first commercial solar thermal plant was
erected in California's Mojave Desert in 1984. Despite the success of this
project, and the great potential of solar thermal plants in general, only a
handful have been built worldwide in the past decade, though there are a number
in the planning stages.
15. How much of the world's energy does the United States
use? Though we make up just 6% of the world's population, we,
the citizens of the United States, consume 25-30% of the energy produced in the
world today. We consume twice as much energy as the average British citizen, two
and-a-half times as much as the average Japanese citizen, and 106 times that of
the average Bangladeshi. Consequently, we Americans produce, per capita, the
most greenhouse gases on the planet. As of 1996, each of us here in the US
produced, on average, almost twice the greenhouse gases of the average German,
and 80 times that of the average Indian. But don't despair! Think of all
the room we have to improve! According to www.energystar.gov, if, over the next
ten years, everyone in the U.S. chose energy-efficient appliances, "we would
cut the nation's utility bills by up to $100 billion and make major reductions
in greenhouse gas emissions at the same time."

1 comment:

  1. Nowaday's we are facing problem of energy resources,Solar Energy is the Best solution for it, because it provide a clean alternative to
    fossil fuels as well as renewable resource of energy.
    Solar pv