What is solar energy ?

Solar energy is radiant energy that's produced by the sun. Daily the sun radiates, or sends out, a huge volume of energy. The sun radiates more energy in a 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 mostly 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 millions of years for the energy from the Sun’s core to make its way to the solar surface, and 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 speed of light.

Only a small part of the energy radiated by the sun into space strikes our planet, one part in two billion. Yet this quantity of energy is enormous. Every day enough energy strikes America 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 which hits our planet is reflected back into space. Another 30 percent is used to evaporate water, which, lifted in to the atmosphere, produces rainfall. Solar energy is absorbed by plants, the land, and the oceans. The rest could be used to supply our energy needs.

Who "invented" solar energy ?

Folks have harnessed solar energy for hundreds of years. 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. More than 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 technology in earnest. One important development was a remarkably efficient solar boiler invented by Charles Greeley Abbott, a united states 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 1920's and was in full swing just before The second world war. This growth lasted until the mid-1950's when lower-cost fuel sources such as natural gas (and propane) became the primary fuel for heating American homes.

The public and world governments remained largely indifferent to the possibilities of solar power prior to the oil shortages of the 1970's. Today, people use solar power to heat buildings and water and also to generate electricity.

How we use solar power today ?

Solar power is used in a number of different ways, of course. There are 2 very basic types of solar power:

* Solar thermal energy collects the sun's warmth by transferring heat from a collector to storage or usage via water or in an anti-freeze (glycol) mixtures, or by forced-air circulation. (active solar systems)

* Solar photovoltaic energy converts the sun's radiation to usable electricity. ("PV")

Listed below are the five most practical and popular techniques solar energy is employed:

1. Small portable solar photovoltaic systems. We have seen these used everywhere, from calculators to solar garden tools. Portable units can be utilized 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 method 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 method of collecting the sun's energy is much 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 three years or less.

4. Integrating solar photovoltaic energy into your home or business power. In most parts of the world, solar photovoltaics is an economically feasible solution to supplement the power of your home. In Japan, photovoltaics are competitive with other kinds of power. In America, new incentive programs make this form of solar energy 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 use of building integrated solar photovoltaics.

5. Large independent photovoltaic systems. For those who 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 sustainable energy to stay 'off the grid.'

There is another simple, different way to use the sun's heat. The architectural design of a home or building may be modified -- larger glass, better insulation, indoor layout and heat storage "mass" -- using the sun to heat or naturally cool indoor spaces. This approach is called "passive solar design" and has been around for thousands of years dating back to Native American cliff dwellers, and used by Romans in urban design, among other cultures.

How 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 energy created then flows into an inverter. The inverter transforms the power into basic voltage and AC electricity.

PV cells are prepared with particular materials called semiconductors like silicon, which is presently the most generally used. When light hits the Photovoltaic cell, a specific share of it is absorbed inside the semiconductor material. This means that the energy of the absorbed light is given to the semiconductor.

The energy unfastens the electrons, permitting them to run freely. Photovoltaic cells also have more than one 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 energy ?

Pro Solar Arguments

- Heating our homes with oil or natural gas or using electricity from power plants running with coal and oil is a reason behind global warming and climate disruption. Solar power, on the other hand, is clean and environmentally-friendly.

- Solar hot-water heaters require little maintenance, and their initial investment may be recovered in just a relatively limited time.

- Solar hot-water heaters can work in almost any climate, even in very cold ones. You just have to choose the best system for your climate: drainback, thermosyphon, batch-ICS (Integrated Collection and Storage), etc.

- Maintenance costs of solar powered systems are usually minimal and the warranties offered by reputable companies can spam several years duration, protecting your investment.

- Financial incentives (USA, Canada, European states…) can reduce the cost of the first investment in solar technologies. The U.S. government, as an 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 initial investment in Solar Hot water heaters or in Solar PV 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 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-con isn't, till now, a truly economical option.

- The efficiency of solar powered systems is rather dependent on sunlight resources. It's in colder climates, where heating or electricity needs are higher, that the efficiency is smaller.

About The Author:

Barbara Young's writings are focused entirely on helping people save energy using solar power to reduce CO2 emissions and energy dependency. Her website is: http://www.12voltsolarpanels.net/rv-solar-panels-101-ultimate-guide-12-volt-battery-charging

Base URL -- http://www.energybuilder.com

Created: 06/27/2010