The following
article is guest written by Barbara
Young.
What is solar energy?
Solar power is
radiant energy which is produced by the sun. Each day the sun radiates, or
sends out, an incredible volume of energy. The sun radiates more energy in one
second than people have used since the beginning of time!
The energy of the
Sun comes from within the sun itself. Like other stars, the sun is really a big
ball of gases––mostly hydrogen and helium atoms.
The hydrogen atoms
in the sun’s core combine to form helium and generate energy in a process
called nuclear fusion.
During nuclear
fusion, the sun’s extremely high pressure and temperature cause hydrogen atoms
to come apart and their nuclei (the central cores of the atoms) to fuse or
combine. Four hydrogen nuclei fuse to become one helium atom. However the
helium atom contains less mass compared to four hydrogen atoms that fused. Some
matter is lost during nuclear fusion. The lost matter is emitted into space as
radiant energy.
It takes millions of
years for the energy in the sun’s core to make its way to the solar surface,
and then somewhat over eight minutes to travel the 93 million miles to earth.
The solar energy travels to the earth at a speed of 186,000 miles per second,
the velocity of light.
Only a small
percentage of the energy radiated from the sun into space strikes our planet,
one part in two billion. Yet this amount of energy is enormous. Everyday enough
energy strikes the USA to supply the nation’s energy needs for one and a half
years!
Where does all this
energy go?
About 15 percent of
the sun’s energy that hits our planet is reflected back into space. Another 30
percent is used to evaporate water, which, lifted into the atmosphere, produces
rainfall. Solar power also is absorbed by plants, the land, and the oceans. The
remaining could be employed to supply our energy needs.
Who invented solar technology?
People have
harnessed solar technology for centuries. Since the 7th century B.C., people
used simple magnifying glasses to concentrate the light of the sun into beams
so hot they would cause wood to catch fire. Over 100 years ago in France, a
scientist used heat from a solar collector to produce steam to drive a steam
engine. In the beginning of this century, scientists and engineers began
researching ways to use solar technology in earnest. One important development was a remarkably efficient solar
boiler introduced by Charles Greeley Abbott, an american astrophysicist, in
1936.
The solar hot water heater gained popularity
at this time in Florida, California, and the Southwest. The industry started in
the early 1920s and was in full swing right before World War II. This growth
lasted before mid-1950s when low-cost propane had become the primary fuel for
heating American homes.
The public and world governments remained
largely indifferent to the possibilities of solar technology prior to the oil
shortages of the1970s. Today, people use solar technology to heat buildings and
water and to generate electricity.
How we use solar power today?
Solar energy is used in a number of
different ways, of course. There are two very basic types of solar power:
*
Solar thermal energy collects the sun's warmth through one of two means: in
water or in an anti-freeze (glycol) mixture.
*
Solar photovoltaic energy converts the sun's radiation to usable electricity.
Let us discuss the five most practical and
popular methods solar energy is employed:
1.
Small portable solar photovoltaic systems. We see these used everywhere, from
calculators to solar garden tools. Portable units can be utilised for
everything from RV appliances while single panel systems are used for traffic
signs and remote monitoring stations.
2.
Solar pool heating. Running water in direct circulation systems via a solar
collector is a very practical way to heat water for your pool or hot tub.
3.
Thermal glycol energy to heat water. In this method (indirect circulation),
glycol is heated by sunshine and the heat is then transferred to water in a hot
water tank. This process of collecting the sun's energy is a lot more practical
now than in the past. In areas as far north as Edmonton, Alberta, solar thermal
to heat water is economically sound. It can pay for itself in three years or
less.
4.
Integrating solar photovoltaic energy into your home or office power. In
numerous parts of the world, solar photovoltaics is an economically feasible
solution to supplement the power of your property. In Japan, photovoltaics are
competitive with other types of power. In the US, new incentive programs make
this form of solar technology ever more viable in many states. An increasingly
popular and practical way of integrating solar energy into the power of your
home or business is through the use of building integrated solar photovoltaics.
5.
Large independent photovoltaic systems. When you have enough sun power at your
site, you could possibly go off grid. You may also integrate or hybridize your
solar power system with wind power or other kinds of renewable energy to stay
'off the grid.'
How do Photovoltaic panels work ?
Silicon is mounted beneath non-reflective
glass to produce photovoltaic panels. These panels collect photons from the
sun, converting them into DC electrical power. The power created then flows
into an inverter. The inverter transforms the energy into basic voltage and AC
electricity.
Photovoltaic cells are prepared with
particular materials called semiconductors for example silicon, which is
presently the most generally used. When light hits the Photovoltaic cell, a
certain share of it is absorbed inside the semiconductor material. This means
that the energy of the absorbed light is given to the semiconductor.
The power unfastens the electrons,
permitting them to run freely. Solar cells also have one or more electric
fields that act to compel electrons unfastened by light absorption to flow in a
specific direction. This flow of electrons is a current, and by introducing
metal links on the top and bottom of the -Photovoltaic cell, the current can be
drawn to use it externally.
What are the pros and cons of solar
technology ?
Solar Pro Arguments
- Heating our homes with oil or propane or
using electricity from power plants running with coal and oil is a reason for
climate change and climate disruption. Solar energy, on the contrary, is clean
and environmentally-friendly.
- Solar hot-water heaters require little
maintenance, and their initial investment could be recovered within a
relatively limited time.
- Solar hot-water heaters can work in
nearly every climate, even just in very cold ones. You just have to choose the
best system for your climate: drainback, thermosyphon, batch-ICS, etc.
- Maintenance costs of solar powered
systems are minimal and also the warranties large.
- Financial incentives (USA, Canada,
European states…) can help to eliminate the price of the first investment in
solar technologies. The U.S. government, for example, offers tax credits for
solar systems certified by by the SRCC (Solar Rating and Certification
Corporation), which amount to 30 percent of the investment (2009-2016 period).
Solar Cons Arguments
- The first investment in Solar Water
heaters or in Photovoltaic Electric Systems is greater than that required by
conventional electric and gas heaters systems.
- The payback period of solar PV-electric
systems is high, as well as those of solar space heating or solar cooling (only
the solar domestic hot water heating payback is short or relatively short).
- Solar water heating do not support a
direct in conjunction with radiators (including baseboard ones).
- Some air cooling (solar space heating and
the solar cooling systems) are very pricey, and rather untested technologies:
solar air-con isn't, till now, a really economical option.
- The efficiency of solar powered systems
is rather influenced by sunlight resources. It's in colder climates, where
heating or electricity needs are higher, that the efficiency is smaller.
than your tea
pot will hold. 
