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Solar Energy – an easy approach to learn how solar panels work


Author: Barbara Young

Article:

What’s solar power ?

  Solar energy is radiant energy which is produced by the sun. Every day the sun radiates, or sends out, an immense quantity of energy. The sun radiates more energy in a single second than humans have used since the beginning of time!

  The energy of the sun derives from within the sun itself. Like other stars, the sun is 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. The helium atom contains less mass than four fused hydrogen atoms. Some matter is lost during nuclear fusion. The lost matter is emitted into space as radiant energy.

  It takes an incredible number of years for the energy in the sun’s core to make its way to the solar surface, and then just a little over eight minutes to travel the 93 million miles to earth. This solar energy travels to the earth at a speed of 186,000 miles per second, the velocity of light.

  Only a small part of the power radiated by the sun into space strikes the earth, one part in two billion. Yet this volume of energy is enormous. Daily, enough energy strikes North America to provide its energy needs for one and a half years!

Where does all of this energy go?

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

Who invented solar energy harvesting?

  People have harnessed solar energy 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’d cause wood to catch fire. More than a century 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 power in earnest. One important development was a remarkably efficient solar boiler introduced by Charles Greeley Abbott, an astrophysicist, in 1936.

  The solar water heater became popular at this time in Florida, California, and the Southwest. The industry started in the early 1920s and was in full swing just before The second World War. This growth lasted prior to the mid-1950s when low-cost, natural gas took over as primary fuel for heating North American homes.

  People 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 also to generate electricity.

How do we use solar power today?

  Solar energy can be used in several different ways, of course. There’s two simple 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 (PV) energy converts the sun’s radiation to usable electricity.

Here are the five most practical and popular methods solar energy can be used:

 1. Small portable solar photovoltaic systems: we see these used everywhere, from calculators to solar garden products. Portable units can be used for everything from RV appliances while single panel systems can be used for traffic signs and remote monitoring stations.

 2. Solar pool heating: running water in direct circulation systems through a solar collector is an extremely practical solution to heat water for your pool or spa.

 3. Thermal glycol energy to heat water: in this method (indirect circulation), glycol is heated by sunlight, the heat is then transferred to water in a hot water tank. This process of collecting the sun’s energy is much more practical now than ever before. In areas as far north as Edmonton, 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 many parts on the planet, 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 North America, new incentive programs make this form of solar energy ever more viable. 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: For those who have enough sun power where you live, you might be able to go “off-grid”. You may also integrate or hybridize your solar energy system with wind power or other kinds of alternative energy to stay off the grid.

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

  PV cells are prepared with particular materials called semiconductors such as silicon, which is presently the most frequently used. As light hits a photovoltaic cell, a share of it is absorbed into, and therefore captured by, the semiconductor material.

  The captured energy 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 at either end of the photovoltaic cell, the current can be drawn from for external use.

  Do you know the benefits and drawbacks of solar power ?

Pro solar points

Heating our homes with oil or propane or using electricity from power plants running with coal and oil causees climate change. Solar power, on the other hand, is clean and environmentally-friendly.

Solar hot-water heaters require little maintenance, and their initial investment could be recovered within a relatively short time. 

Solar hot-water heaters can work in nearly any climate, even in very cold ones. Simply choose the best system for your climate: drainback, thermosyphon, batch-ICS, etc. 

Maintenance costs of solar powered systems are minimal and the warranties are often comprehensive.

Financial incentives offered where you live can reduce the initial investment costs. 

Solar drawbacks

The initial investment in Solar Hot water heaters or in Solar PV Electric Systems is higher than that required by conventional electric and gas heaters systems.

The payback period of solar PV-electric systems is long, as well as those of solar space heating or cooling (only solar hot water heating has a relatively short payback period).

Solar water heating does not work well in conjunction with radiators (including baseboard types).

Some AC (solar space heating and cooling systems) are pricey, and somewhat untested, technologies. Solar air conditioning hasn’t been, until now, an economical option.

The efficiency of solar powered systems is dependent on available sunlight. In colder climates, where heating or electricity needs are higher, these systems can be less efficient.

 

Barbara Young writes on RV solar panel kits in her personal hobby blog 12voltsolarpanels.net. Her efforts are centered on helping people save energy using solar power to reduce CO2 emissions and energy dependency.

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This entry was posted on Tuesday, July 27th, 2010 at 12:25 am and is filed under MINDFUL LIVING. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

Synergy Magazine: Vancouver Island, BC, Canada