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Sunday, June 20, 2010

Guest Blog Post : Barbara Young

I am excited to introduce a first ever guest blog post on The Revit Kid.  Our guest author this week is Barbara Young who writes at 12 Volt Solar Panels.... Given that this is a student related blog I thought it would be great to have her give a little introduction to solar panel technologies.  Do you REALLY understand solar panels?  When you are modeling a building in Revit that uses solar panels... How to go about it?  

Here’s an instant way to learn how solar panels work

What's solar power ?
Solar energy is radiant energy that is produced by the sun. Daily the sun radiates, or sends out, an incredible volume of energy. The sun radiates more energy in a single 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. But 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 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 portion of the energy radiated from the sun into space strikes the earth, one part in two billion. Yet this amount of energy is enormous. Each day enough energy strikes the united states to provide 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 the planet earth is reflected back into space. Another 30 percent is used to evaporate water, which, lifted into the atmosphere, produces rainfall. Solar power is also absorbed by plants, the land, and the oceans. The remaining could be employed to supply our energy needs.
Who invented solar energy ?
Humans have harnessed solar power for centuries. 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 would cause wood to catch fire. Over a century ago in France, a scientist used heat from a solar collector to create 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 a remarkably efficient solar boiler invented 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 just before World War II. This growth lasted until the mid-1950s when low-cost propane became the primary fuel for heating American homes.
People and world governments remained largely indifferent to the possibilities of solar energy before oil shortages of the1970s. Today, people use solar power to heat buildings and water and to generate electricity.
How we use solar power today ?
Solar energy can be used in a variety of ways, of course. There's two simple kinds of solar power:
* Solar thermal energy collects the sun's warmth through 1 of 2 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 solutions solar energy is employed:
1. Small portable solar photovoltaic systems. We see these used everywhere, from calculators to solar garden products. Portable units may be used 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 an extremely 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 the sun's rays and the heat is then transferred to water in a hot water tank. This method of collecting the sun's energy is a lot 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 of the world, solar photovoltaics is an economically feasible solution to supplement the power of your home. 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. A frequent and practical method 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. If 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 alternative energy to stay 'off the grid.'
How do 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 electric power. The power created then flows into an inverter. The inverter transforms the energy into basic voltage and AC electrical energy.
Solar 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 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 benefits and drawbacks of solar technology ?
Solar Pro Arguments
- Heating our homes with oil or natural gas or using electricity from power plants running with oil and coal is a reason behind climatic change and climate disruption. Solar power, on the contrary, is clean and environmentally-friendly.
- Solar hot-water heaters require little maintenance, and their initial investment can be recovered in just a relatively limited time.
- Solar hot-water heaters can work in almost any climate, even just in very cold ones. Simply choose the right 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 aid in eliminating 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 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 costly, and rather untested technologies: solar air conditioning isn't, till now, a really 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.

Who am i ? - Barbara Young writes on solar RV battery charger in her personal hobby weblog Her work is focused entirely on helping people save energy using solar energy to lower CO2 emissions and energy dependency.

Thanks for the post Barbara and I hope my readers learned something new today...