Solar or photovoltaic solar cells (PV) are electronic devices that essentially convert solar energy (fuel) of sunlight into electric energy or electricity. The basic physics of solar cells are the same semiconductor principles as diodes and transistors that form the building blocks of the entire world of electronics. Solar cells convert energy as long as the there is sunlight. In the evenings and cloudy conditions, the conversion process diminishes. It stops completely at dusk and resumes at dawn. Solar cells do not store electricity, but batteries can be used to store energy.
One of the most fascinating aspects of the solar cells is the ability to convert the most abundant and free form of energy into electricity, without moving parts or components and without producing any adverse forms of pollution that affect the ecology, as is associated with most known forms of nonrenewable energy production methods, such as fossil fuel, hydroelectric, or nuclear energy generating plants.
A Brief History of the Photoelectric Phenomenon
In later part of the 19th century, physicists discovered a phenomenon, when light was incident on liquids and metal cell surfaces, electrons were released. However, no one had an explanation for the bizarre occurrences. At the turn of the 20th century, Albert Einstein provided a theory on the PHOTOELECTRIC EFFECT, for which he won the Nobel Prize in physics and laid the groundwork for the theory of the PHOTOVOLTAIC EFFECT. The following diagram shows the photoelectric effect. When light is shone on a metal, electrons are released that are attracted toward a positive charged plate, thereby giving rise to photoelectric current.
Einstein explained the observed phenomenon by a contemporary theory of QUANTIZED ENERGY LEVELS, which was previously developed by Max Plank. The theory described light as being made out of miniscule bundles of energy called PHOTONS. Photons impinging on metals or semiconductors knock electrons from atoms. In the 1930s, these theorems led to new discipline in physics called QUANTUM MECHANICS, which consequently led to the discovery of transistors in 1950s and the development of semiconductor electronics.
Lighting
Providing lighting within a building can account for up to 30% of the energy used. There are several options for reducing this energy usage. The easiest method for reducing the energy used to provide lighting is to invest in compact fluorescent lights, as opposed to traditional incandescent lights. Compact fluorescent lights use approximately 75% less energy than typical incandescent lights. A 15 watt compact fluorescent light will supply the same amount of light as a 60 watt incandescent, while using only 25% of the energy that a 60 watt incandescent light would require. Compact fluorescent lights also last significantly longer than incandescent lights, with an expected lifetime of 10,000 hours on most models. Most compact fluorescent lights also come with a one-year warranty. Another option for saving money and energy related to lighting is to use torchieres. In recent years halogen torchieres have become relatively popular. However, halogen torchieres create extremely high levels of heat, approximately 90% of the energy used by a halogen lamp is transferred to heat, not light. Some halogen lamps generate enough heat to fry an egg on the top of the lamp. These lamps create a fire hazard due to the possibility of curtains touching the lamp and igniting or a lamp falling over and igniting carpet. Great alternatives to these types of lamps are compact fluorescent torchieres. Whereas a halogen torchieres used 4 hours per day will use approximately438 kilowatt-hours throughout the year, a compact fluorescent torchieres used 4 hours per day will only use 80 kilowatt hours throughout the year. If you currently pay $0.11 per kilowatt-hour this would save you over $30 per year, just for changing one lamp.
Economic Analysis
It should be noted that economic cost analysis discussed below should not over shadow, ignore, or dismiss immense intangible cost benefits of solar power systems as a renewable and sustainable source of energy. When considering air quality degradation by nonrenewable energy sources, such as coal and fossil fuels, which generate over 1,000 pounds of carbon dioxide for every megawatt hour of electric power, solar or any sustainable type of renewable energy must be given a significant tangible value. Upon completion of the overall hardware and manpower installation costs outlined above, the solar power engineer must evaluate the prevailing and projected costs associated with the electric energy for the life span of the solar power system, which may range from 10 years to 25 years, depending on the employed choice of PV technology. To establish an economic analysis framework, the solar power engineer assesses the cost benefit and financial merits of the solar power system investment. The designer should be familiar with engineering econometrics.
Einstein explained the observed phenomenon by a contemporary theory of QUANTIZED ENERGY LEVELS, which was previously developed by Max Plank. The theory described light as being made out of miniscule bundles of energy called PHOTONS. Photons impinging on metals or semiconductors knock electrons from atoms. In the 1930s, these theorems led to new discipline in physics called QUANTUM MECHANICS, which consequently led to the discovery of transistors in 1950s and the development of semiconductor electronics.
Lighting
Providing lighting within a building can account for up to 30% of the energy used. There are several options for reducing this energy usage. The easiest method for reducing the energy used to provide lighting is to invest in compact fluorescent lights, as opposed to traditional incandescent lights. Compact fluorescent lights use approximately 75% less energy than typical incandescent lights. A 15 watt compact fluorescent light will supply the same amount of light as a 60 watt incandescent, while using only 25% of the energy that a 60 watt incandescent light would require. Compact fluorescent lights also last significantly longer than incandescent lights, with an expected lifetime of 10,000 hours on most models. Most compact fluorescent lights also come with a one-year warranty. Another option for saving money and energy related to lighting is to use torchieres. In recent years halogen torchieres have become relatively popular. However, halogen torchieres create extremely high levels of heat, approximately 90% of the energy used by a halogen lamp is transferred to heat, not light. Some halogen lamps generate enough heat to fry an egg on the top of the lamp. These lamps create a fire hazard due to the possibility of curtains touching the lamp and igniting or a lamp falling over and igniting carpet. Great alternatives to these types of lamps are compact fluorescent torchieres. Whereas a halogen torchieres used 4 hours per day will use approximately438 kilowatt-hours throughout the year, a compact fluorescent torchieres used 4 hours per day will only use 80 kilowatt hours throughout the year. If you currently pay $0.11 per kilowatt-hour this would save you over $30 per year, just for changing one lamp.
Economic Analysis
It should be noted that economic cost analysis discussed below should not over shadow, ignore, or dismiss immense intangible cost benefits of solar power systems as a renewable and sustainable source of energy. When considering air quality degradation by nonrenewable energy sources, such as coal and fossil fuels, which generate over 1,000 pounds of carbon dioxide for every megawatt hour of electric power, solar or any sustainable type of renewable energy must be given a significant tangible value. Upon completion of the overall hardware and manpower installation costs outlined above, the solar power engineer must evaluate the prevailing and projected costs associated with the electric energy for the life span of the solar power system, which may range from 10 years to 25 years, depending on the employed choice of PV technology. To establish an economic analysis framework, the solar power engineer assesses the cost benefit and financial merits of the solar power system investment. The designer should be familiar with engineering econometrics.
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