Sunday, June 20, 2010

Guest Writer on Solar Panels


I am always very happy to publish pieces by guest writers. Barbara Young contacted me recently and offered the following piece for publication. Barbara is quite evidently a keen sustainable energy enthusiast. She keeps a hobby website herself and writes about her passion to help achieve a greener world through wise energy usage.

I am delighted to publish her post as received, and wish her the very best with her efforts. You will find a link to her site at the end of the piece.

How solar panels work

by Guest Writer; Barbara Young

What is solar energy ?

Solar power is radiant energy which is produced by the sun. Every day the sun radiates, or sends out, an enormous quantity of energy. The sun radiates more energy in one second than people have used since the beginning of time!

The energy of the Sun derives from within the sun itself. Like other stars, the sun is known as a big ball of gases––mostly hydrogen and helium atoms. The hydrogen atoms in the sun’s core combine to create 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 than the four hydrogen atoms that fused. Some matter is lost during nuclear fusion. The lost matter is emitted into space as radiant energy.

It takes countless years for the energy in the sun’s core to make its way to the solar surface, and just a little 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.

Simply a small portion of the power radiated by the sun into space strikes the earth, one part in two billion. Yet this quantity of energy is enormous. Every day enough energy strikes the united states to supply the nation’s energy needs for one and a half years!

Where does all of this energy go?

About 15 percent of the sun’s energy which hits our planet is reflected back to space. Another 30 percent is used to evaporate water, which, lifted into the atmosphere, produces rainfall. Solar energy is absorbed by plants, the land, and the oceans. The rest could be employed to supply our energy needs.

Who invented solar energy ?

Humans have harnessed solar power for years and years. As early as the 7th century B.C., people used simple magnifying glasses to concentrate the light of the sun into beams so hot they'd 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. At first of this century, scientists and engineers began researching ways to use solar power in earnest. One important development was obviously a remarkably efficient solar boiler introduced by Charles Greeley Abbott, a united states astrophysicist, in 1936.

The solar 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 The second world war. This growth lasted before mid-1950s when low-cost gas took over as primary fuel for heating American homes.

The public and world governments remained largely indifferent to the possibilities of solar energy before oil shortages of the1970s. Today, people use solar technology to heat buildings and water and to generate electricity.

How we use solar energy today ?

Solar power is used in a variety of ways, of course. There are 2 very basic forms 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.

Five most practical and popular ways that solar power 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 can be used 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 natural sunlight and the heat is then transferred to water in a warm water tank. This technique of collecting the sun's energy is more practical now than ever. In areas as far north as Edmonton, Alberta, solar thermal to heat water is economically sound. It can pay for itself in 3 years or less.

4. Integrating solar photovoltaic energy into your home or office power. In numerous parts on the planet, solar photovoltaics is an economically feasible way to supplement the power of your property. In Japan, photovoltaics are competitive with other types of power. In the USA, new incentive programs make this form of solar technology ever more viable in many states. A frequent and practical way of integrating solar energy into the power of your home or business is through the usage of building integrated solar photovoltaics.

5. Large independent photovoltaic systems. If you have enough sun power at your site, you might be able to go off grid. It's also possible to integrate or hybridize your solar power system with wind power or other forms of renewable energy to stay 'off the grid.'

How can Photovoltaic panels work ?

Silicon is mounted beneath non-reflective glass to create photovoltaic panels. These panels collect photons from the sun, converting them into DC electrical energy. The power created then flows into an inverter. The inverter transforms the energy into basic voltage and AC electrical energy.

Photovoltaic cells are prepared with particular materials called semiconductors like silicon, which is presently the most generally used. When light hits the Photovoltaic cell, a particular 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 power 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.

Do you know the benefits and drawbacks of solar energy ?

Solar Pro Arguments

· Heating our homes with oil or propane or using electricity from power plants running with oil and coal is a reason behind global warming and climate disruption. Solar energy, on the contrary, is clean and environmentally-friendly.
· Solar hot-water heaters require little maintenance, and their initial investment may be recovered in just a relatively short time.
· Solar hot-water heaters can work in almost any climate, even just in very cold ones. Simply choose the best system for your climate: drain-back, thermo-syphon, batch-ICS, etc.
· Maintenance costs of solar powered systems are minimal and the warranties large.
· Financial incentives (USA, Canada, European states…) can aid in eliminating the price of the initial investment in solar technologies. The U.S. government, for instance, 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 warm water heating payback is short or relatively short).
· Solar water heating do not support a direct combination 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 conditioning isn't, till now, a really economical option.
· The efficiency of solar powered systems is rather determined by sunlight resources. It's in colder climates, where heating or electricity needs are higher, that the efficiency is smaller.

Barbara Young has a personal hobby website, here is the link: Her work is related to helping people save energy using solar power to lower CO2 emissions and energy dependency.


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