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The spectrum of electromagnetic radiation striking the Earth's atmosphere spans a range of 100 nm to about 1 mm . This can be divided into five regions in increasing order of wavelengths : Ultraviolet C or (UVC) range, which spans a range of 100 to 280 nm. The term ultraviolet refers to the fact that the radiation is at higher frequency than violet light (and, hence also invisible to the human eye ) Ultraviolet B or (UVB) range spans 280 to 315 nm. It is also greatly absorbed by the atmosphere, and along with UVC is responsible for the photochemical reaction leading to the production of the ozone layer Ultraviolet A or (UVA) spans 315 to 400 nm. It has been traditionally held as less damaging to the DNA , and hence used in tanning and PUVA therapy for psoriasis . Visible range or light spans 380 to 780 nm. As the name suggests, it is this range that is visible to the naked eye. Infrared range that spans 700 nm to 106 nm (1 mm ). It is responsible for an important part of the electromagnetic radiation that reaches the Earth
Concentrated solar power systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam.
Solar cells are often electrically connected and encapsulated as a module . Photovoltaic modules often have a sheet of glass on the front (sun up) side, allowing light to pass while protecting the semiconductor wafers from abrasion and impact due to wind-driven debris, rain , hail , et cetera. Solar cells are also usually connected in series in modules, creating an additive voltage . Connecting cells in parallel will yield a higher current. Modules are then interconnected, in series or parallel, or both, to create an array with the desired peak DC voltage and current.
The solar cell works in three steps: Photons in sunlight hit the solar panel and are absorbed by semiconducting materials, such as silicon. Electrons (negatively charged) are knocked loose from their atoms, allowing them to flow through the material to produce electricity. Due to the special composition of solar cells, the electrons are only allowed to move in a single direction. An array of solar cells converts solar energy into a usable amount of direct current (DC) electricity. Most commercially available solar cells are capable of producing electricity for at least twenty years without a significant decrease in efficiency.
Slide 14- after 1st pt Techniques such as timed planting cycles, tailored row orientation, staggered heights between rows and the mixing of plant varieties can improve crop yields.
Slide 15- after 1st pt This passive technology directly offsets energy use by replacing artificial lighting, and indirectly offsets non-solar energy use by reducing the need for air-conditioning
After 2nd pt- HSL systems collect sunlight using focusing mirrors that track the Sun and use optical fibers to transmit it inside the building to supplement conventional lighting.
Slide 19-after 2nd pt The use of evaporation ponds to obtain salt from sea water is one of the oldest applications of solar energy. Modern uses include concentrating brine solutions used in leach mining and removing dissolved solids from waste streams
Slide 22-after 2nd pt Aside from electrolysis driven by photovoltaic or photochemical cells, several thermochemical processes have also been explored. One such route uses concentrators to split water into oxygen and hydrogen at high temperatures (2300-2600 °C).
Slide 23- after 2nd pt As sunlight shines on the balloon, the air inside is heated and expands causing an upward buoyancy force, much like an artificially heated hot air balloon. Last pt Unlike rockets, solar sails require no fuel. Although the thrust is small compared to rockets, it continues as long as the Sun shines onto the deployed sail and in the vacuum of space significant speeds can eventually be achieved
Slide 24-after 3rd pt A prime example of this is in space, where satellites are powered by high efficiency solar cells. After 6th pt Eliminates the problem of finding the required space for solar panel placement. After 7th pt Although the initial investment of solar cells may be high, once installed, they provide a free source of electricity, which will pay off over the coming years.
slide 26- Environmental Effects of Solar Energy carbon emissions The best thing about solar energy in terms of its environmental effects is that it produces almost no carbon emissions or greenhouse gases. It doesn't burn oil, it doesn't produce toxic waste, and its lack of moving parts reduces the chances of an environmentally devastating accident to nil. Indeed, the only pollutants which factor into solar power are those involved in the construction and transportation of its parts; that ranks it among the cleanest forms of energy on Earth. Implementing solar energy on a large scale would reduce its environmental footprint to a tiny fraction of its current levels. Renewable energy Solar power is also environmentally advantageous because its energy supply never runs out. Sunlight will always shine upon the Earth and, as long as it does, hold energy which solar technology can exploit. Contrast this with fossil fuels such as coal or oil, which need to be mined or drilled and thus have a tremendous environmental impact, even in comparatively safe circumstances. Abundant Components The photovoltaic cells which constitute most solar energy systems are usually made of silicon, one of the most common minerals found on Earth. That means that creating the components is extremely easy, doesn't require mining or drilling in a dangerous locale to produce, and can be acquired without involvement in politically unstable areas such as the Middle East. The environmental effects of this are subtle but, because fewer resources are expended in the acquisition of silicon, its overall effect on the ecosystem is reduced. Cadmium Cadmium is used in cadmium telluride solar cells as a semiconductor to convert solar energy into electricity. Though used in very small amounts, it is extremely toxic and can build up in a given ecosystem if it isn't monitored. Firms which make this kind of solar cell often instigate recycling programs so that damaged or unusable cells don't inadvertently damage the surrounding environment. Space Considerations Solar panels are not as efficient as they could be -- one of the reasons why they have not been widely implemented yet. To capture appreciable amounts of energy, they require a large number of cells, which can take up a considerable amount of space. One practical solution is to mount the cells on a rooftop, which saves a lot of space while still allowing them maximum exposure to the sun. Large-scale solar farms still require a lot of room, however, and trees and bushes can't coexist with them lest they block sunlight from the receivers.
Slide 27-after 2nd pt-- MEDICAL USES OF SOLAR ENERGY It deactivates the DNA from pathogens and makes it impossible for them to multiply. Ultraviolet light damages the nucleic acid of microorganisms which keeps the organism from reproducing. After 4th pt- Dr. Stallone at Arizona Integrative Medical Center uses ozone or hydrogen peroxide combined with light therapy to restore oxidative metabolism. This treats chronic diseases. After last pt This is called phototherapy. UVA phototherapy is generally used along with psoralen which is a light sensitizing tablet. UVB uses one wavelength to treat skin diseases and is very beneficial for psoriasis. It is also used to treat pruritus, vitiligo and lichen planus. These treatments help heal inflamed tissues, damaged cells and wounds. Ultraviolet germicidal or bactericidal lamps are often used in the medical field to help keep disease under control so it doesn't spread. Common Microorganisms Destroyed by UV Light: Bacillus anthracis Corynebacterium diphtheriae Dysentary bacilli (diarrhea) Escherichia coli (diarrhea) Legionella pneumophilia Mycobacterium tuberculosis Pseudomonas aeruginosa Salmonella (food poisoning) Salmonella paratyphi (enteric fever) Salmonella typhosa (typhoid fever) Shigella dysentariae (dysentery) Shigella flexneri (dysentery) Staphylococcus epidermidis Streptococcus faecaelis Vibro commo (cholera) Bacteriophage (E. Coli) Hepatitis Influenza Poliovirus (poliomyelitis) Baker's yeast What are the Advantages of UV Disinfection? Environmentally friendly, no dangerous chemicals to handle or store, no problems of overdosing. Universally accepted disinfection system for potable and non-potable water systems. Low initial capital cost as well as reduced operating expenses when compared with similar technologies such as ozone, chlorine, etc. Immediate treatment process, no need for holding tanks, long retention times, etc. Extremely economical, hundreds of gallons may be treated for each penny of operating cost. Low power consumption. No chemicals added to the water supply - no by-products (i.e. chlorine + organics = trihalomethanes). Safe to use. No removal of beneficial minerals. No change in taste, odor, pH or conductivity nor the general chemistry of the water. Automatic operation without special attention or measurement, operator friendly. Simplicity and ease of maintenance, TWT Deposit Control System prevents scale formation of quartz sleeve, annual lamp replacement, no moving parts to wear out. No handling of toxic chemicals, no need for specialized storage requirements, no OHSA requirements. Easy installation, only two water connections and a power connection. More effective against viruses than chlorine. Compatible with all other water processes (i.e., RO, filtration, ion exchange, etc.)
Solar Energy Health Effects on Humans Slide 28- after 1st pt Electromagnetic Radiation From Solar Panels Modern solar systems use components that radiate high levels of radio frequency electromagnetic radiation, which poses health risks to those with electromagnetic hypersensitivity (EHS). The primary health hazard involved with solar energy generation is that people with EHS get sick from electromagnetic radiation in even very small amounts. Such a health problem may be triggered by small frequencies from cell phones, computers and other electronic appliances. The production of solar energy can further aggravate the situation. Since some of the symptoms of this health risk are common and non-specific, such as headaches and restlessness, a person inside a solar-powered home or building may not even realize what's going on. Silicon Dust from Solar Panels A solar panel's basic component contains pure silicon. Silicon dust is a harmful substance when inhaled, especially over long periods of time. Exposure to this dust can result in a lung disease called silicosis, which causes scar tissue to form in the lungs. This scar tissue reduces the lungs' capacity to process oxygen. Solar cells are also made of non-recyclable materials. Therefore, the absence of an environment-friendly way to dispose of non-functioning solar cells could pose a threat to the environment as well. Exposure to Electrical and Chemical Components of Solar Heat Systems A solar hot water system takes the heat of the sun to warm up bath water. Some solar heat systems can heat up an entire house. These technologies usually have a solar collector that processes the energy to generate heat. These methods pose health risks to chemically or electrically sensitive people, especially if they are constantly exposed to these systems. The Future of Solar Energy With more research and development projects, the health risks related to the acquisition and utilization of solar energy can be better managed and addressed. Hopefully, new solar energy technology will be free from these negative health effects.
Solar energy project in Guyana Summary- A solar energy system will provide 1st ever electricity & HF radio communication for isolated village of 100 Amerindians; students/adults will benefit from DVD/TV educational & entertainment programs Potential Long Term Impact Solar energy/HF radio will improve quality of life for 100 persons in rainforest environment thru immediate radio contact for medical emergencies, community meetings & better educational systems. It will bring smiles to faces via DVD entertainment.
ALTERNATIVE ENERGIES DONE BY AMEENAH KHAN 09/0509/1391
ENERGY <ul><li>It is the ability to do work. </li></ul><ul><li>In physics, work is done when a force applied to an object which moves it some distance in the direction of the force. </li></ul><ul><li>Mathematically, W = Fs, where W is the work done, F is the force applied, and s is the distance moved. </li></ul>
DIFFERENT ENERGY SOURCES <ul><li>‘Traditional’ fuels such as fuel wood, crop wastes, and animal dung.(non-commercial) </li></ul><ul><li>Fossil fuels such as coal, oil and natural gas (commercial ‘traditional’ fuels) </li></ul><ul><li>Non-traditional renewable energy sources as hydro, modern biomass, solar, wind, ocean and geothermal. </li></ul>
ENERGY FORMS <ul><li>SOLAR </li></ul><ul><li>WATER </li></ul><ul><li>WIND </li></ul><ul><li>GEOTHERMAL </li></ul>
WHAT IS SOLAR ENERGY? <ul><li>It is the radiation from the sun that is capable of producing heat, causing chemical reactions, or generating electricity. </li></ul><ul><li>It is the largest source of energy received on Earth, but its intensity on the earth’s surface is quite low. </li></ul><ul><li>Solar energy is rapidly becoming the ultimate energy source because of its non-polluting character and its inexhaustible supply which are in stark contrast to such fossil fuel sources as coal, oil, and natural gas. </li></ul>
COMPOSITION <ul><li>The Sun emits EM radiation across most of the electromagnetic spectrum </li></ul><ul><li>The Sun does, however, emit X-rays , ultraviolet , visible light , infrared , and even Radio waves .When ultraviolet radiation is not absorbed by the atmosphere or other protective coating, it can cause damage to the skin known as sunburn or trigger an adaptive change in human skin pigmentation . </li></ul>
<ul><li>The sunlight that reaches the ground consists of nearly 50% visible light, 45% infrared radiation, and smaller amounts of ultraviolet light and other forms of electromagnetic radiation. </li></ul><ul><li>This radiation can be converted either into: thermal energy or into electrical energy. </li></ul><ul><li>Two main types of devices are used to capture solar energy and convert it into thermal energy: </li></ul><ul><li>Flat-plate collectors and Concentrating collectors. </li></ul><ul><li>The flat plate collectors are used for hot water heating and house heating. </li></ul><ul><li>Concentrating collectors are used when higher temperatures are needed. That is, where they reflect and concentrate sunlight from a wide area. </li></ul>
<ul><li>Solar energy can be converted to electricity using photovoltaic cells/ solar cells. </li></ul><ul><li>This converted energy is used to provide electricity for watches, calculators and cameras. </li></ul><ul><li>Unfortunately, though solar energy is free, the high cost of its collection, conversion and storage has limited its exploitation. </li></ul>
GENERATION OF SOLAR POWER <ul><li>Solar power is the conversion of sunlight into electricity , either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP). </li></ul><ul><li>Photovoltaics converts light into electric current using the photoelectric effect . </li></ul>
Energy storage methods <ul><li>Solar energy can be stored at high temperatures using molten salts. Salts are an effective storage medium because they are low-cost, have a high specific heat capacity and can deliver heat at temperatures compatible with conventional power systems. </li></ul>
SOLAR CELL <ul><li>A solar cell (also called photovoltaic cell or photoelectric cell ) is a solid state device that converts the energy of sunlight directly into electricity by the photovoltaic effect . Assemblies of cells are used to make solar modules , also known as solar panels . The energy generated from these solar modules, referred to as solar power , is an example of solar energy . </li></ul><ul><li>Cells are described as photovoltaic cells when the light source is not necessarily sunlight. These are used for detecting light or other electromagnetic radiation near the visible range, for example infrared detectors , or measurement of light intensity. </li></ul>
SOLAR CELL Solar modules/panels A basic structure of a typical solar cell
<ul><li>Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. </li></ul><ul><li>Active solar techniques include the use of photovoltaic panels and solar thermal collectors to harness the energy. </li></ul><ul><li>Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air . </li></ul><ul><li>Active solar technologies increase the supply of energy and are considered supply side technologies, while passive solar technologies reduce the need for alternate resources and are generally considered demand side technologies. </li></ul>
APPLICATIONS OF SOLAR ENERGY <ul><li>A partial list of solar applications includes space heating and cooling through solar architecture , potable water via distillation and disinfection , daylighting , solar hot water , solar cooking , and high temperature process heat for industrial purposes. </li></ul><ul><li>To harvest the solar energy, the most common way is to use solar panels . </li></ul>
Agriculture and horticulture <ul><li>Agriculture and horticulture seek to optimize the capture of solar energy in order to optimize the productivity of plants. </li></ul><ul><li>Applications of solar energy in agriculture aside from growing crops include pumping water, drying crops, brooding chicks and drying chicken manure </li></ul><ul><li>More recently the technology has been embraced by vinters, who use the energy generated by solar panels to power grape presses. </li></ul><ul><li>Greenhouses convert solar light to heat, enabling year-round production and the growth (in enclosed environments) of specialty crops and other plants not naturally suited to the local climate. </li></ul>
Solar lighting <ul><li>Daylighting systems collect and distribute sunlight to provide interior illumination. </li></ul><ul><li>Hybrid solar lighting is an active solar method of providing interior illumination. </li></ul><ul><li>Solar thermal technologies can be used for water heating, space heating, space cooling and process heat generation </li></ul><ul><li>Solar hot water systems use sunlight to heat water. </li></ul>
Water treatment <ul><li>Solar distillation can be used to make saline or brackish water potable </li></ul><ul><li>Solar water disinfection (SODIS) involves exposing water-filled plastic polyethylene terephthalate (PET) bottles to sunlight for several hours </li></ul><ul><li>It is recommended by the World Health Organization as a viable method for household water treatment and safe storage </li></ul><ul><li>Solar energy may be used in a water stabilisation pond to treat waste water without chemicals or electricity. </li></ul>Solar water heater
Cooking <ul><li>Solar cookers use sunlight for cooking, drying and pasteurization . They can be grouped into three broad categories: box cookers, panel cookers and reflector cookers </li></ul><ul><li>A basic box cooker consists of an insulated container with a transparent lid. </li></ul><ul><li>Panel cookers use a reflective panel to direct sunlight onto an insulated container and reach temperatures comparable to box cookers. </li></ul><ul><li>Reflector cookers use various concentrating geometries (dish, trough, Fresnel mirrors) to focus light on a cooking container. </li></ul>The Solar Bowl in Auroville , India ,
Process heat <ul><li>Solar concentrating technologies such as parabolic dish, trough and Scheffler reflectors can provide process heat for commercial and industrial applications. </li></ul><ul><li>Evaporation ponds are shallow pools that concentrate dissolved solids through evaporation . </li></ul><ul><li>Clothes lines , clotheshorses , and clothes racks dry clothes through evaporation by wind and sunlight without consuming electricity or gas. </li></ul>STEP parabolic dishes used for steam production and electrical generation.
Electrical generation (solar power) <ul><li>Solar power is the conversion of sunlight into electricity , either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP). CSP systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. PV converts light into electric current using the photoelectric effect . </li></ul>
Experimental solar power <ul><li>A solar pond is a pool of salt water (usually 1–2 m deep) that collects and stores solar energy. </li></ul><ul><li>The pond consisted of layers of water that successively increased from a weak salt solution at the top to a high salt solution at the bottom. </li></ul><ul><li>This solar pond was capable of producing temperatures of 90 °C in its bottom layer and had an estimated solar-to-electric efficiency of two percent. </li></ul><ul><li>Thermoelectric , or "thermovoltaic" devices convert a temperature difference between dissimilar materials into an electric current. </li></ul>
Solar chemical <ul><li>Solar chemical processes use solar energy to drive chemical reactions. These processes offset energy that would otherwise come from an alternate source and can convert solar energy into storable and transportable fuels. Solar induced chemical reactions can be divided into thermochemical or photochemical </li></ul><ul><li>Hydrogen production technologies been a significant area of solar chemical research since the 1970s. </li></ul><ul><li>Another approach uses the heat from solar concentrators to drive the steam reformation of natural gas thereby increasing the overall hydrogen yield compared to conventional reforming methods </li></ul><ul><li>Thermochemical cycles characterized by the decomposition and regeneration of reactants present another avenue for hydrogen production. </li></ul>
Solar vehicles <ul><li>Some vehicles use solar panels for auxiliary power, such as for air conditioning, to keep the interior cool, thus reducing fuel consumption </li></ul><ul><li>A solar balloon is a black balloon that is filled with ordinary air. </li></ul><ul><li>Solar sails are a proposed form of spacecraft propulsion using large membrane mirrors to exploit radiation pressure from the Sun. </li></ul>
SOLAR ENERGY PROS <ul><li>Solar panels give off no pollution </li></ul><ul><li>Solar energy produces electricity very quietly. </li></ul><ul><li>It has the ability to harness electricity in remote locations that are not linked to a national grid. </li></ul><ul><li>Very efficient in large areas of the globe. </li></ul><ul><li>Solar panels can be installed on top of many rooftops </li></ul><ul><li>It is affordable in the long run. </li></ul><ul><li>The use of solar energy to produce electricity allows the user to become less dependent on the worlds fossil fuel supplies. </li></ul>
SOLAR ENERGY CONS <ul><li>The major con of solar energy is the initial cost of solar cells. </li></ul><ul><li>Solar energy is only able to generate electricity during daylight hours. This means for around half of each day, solar panels are not producing energy for your home. </li></ul><ul><li>The weather can affect the efficiency of solar cells. </li></ul><ul><li>Pollution can be a con of solar energy, as pollution levels can affect a solar cells efficiency, this would be a major con for businesses or industry wishing to install solar panels in heavily polluted areas, such as cities. </li></ul>
Environmental Effects of Solar Energy <ul><li>Carbon Emissions </li></ul><ul><li>Renewable Energy </li></ul><ul><li>Abundant Components </li></ul><ul><li>Cadmium </li></ul><ul><li>Space Considerations </li></ul>
MEDICAL USES OF SOLAR ENERGY <ul><li>These include, disinfection and sterilization without the use of chemicals. Ultraviolet light is also used to destroy bacteria and viruses. </li></ul><ul><li>It stimulates the immune system and has shown good results in killing blood borne pathogens. </li></ul><ul><li>Some microorganisms destroyed by ultraviolet light are bacillus anthracis, salmonella or food poisoning, shigella dysentariae or dysentery, bacteriophage or E. coli, hepatitis and influenza. </li></ul><ul><li>Ultraviolet light can be combined with other therapies. </li></ul><ul><li>Some kinds of skin conditions can improve with the exposure of ultraviolet light. </li></ul>
Solar Energy Health Effects on Humans <ul><li>These are: </li></ul><ul><ul><li>Electromagnetic Radiation From Solar Panels </li></ul></ul><ul><ul><li>Silicon Dust from Solar Panels </li></ul></ul><ul><ul><li>Exposure to Electrical and Chemical Components of Solar Heat Systems </li></ul></ul><ul><ul><li>The Future of Solar Energy </li></ul></ul>
<ul><li>The body produces vitamin D from sunlight (specifically from the UVB band of ultraviolet light), and excessive seclusion from the sun can lead to deficiency unless adequate amounts are obtained through diet. </li></ul><ul><li>On the other hand, excessive sunlight exposure has been linked to all types of skin cancer caused by the ultraviolet part of radiation from sunlight or sunlamps </li></ul>
<ul><li>A lack of sunlight, on the other hand, is considered one of the primary causes of seasonal affective disorder (SAD), a serious form of the "winter blues". SAD occurrence is more prevalent in locations further from the tropics, and most of the treatments (other than prescription drugs) involve light therapy </li></ul><ul><li>A recent study indicates that more exposure to sunshine early in a person’s life relates to less risk from multiple sclerosis (MS) later in life </li></ul>
SOLAR ENERGY AND GUYANA <ul><li>Solar energy is primarily being installed in the hinterland/remote areas of the country. Currently under the Unserved Areas Electrification Programme, a number of communities have received solar photovoltaic’s home systems. </li></ul><ul><li>Solar power will provide lights, entertainment & emergency communication for 100 persons in Wayling. </li></ul><ul><li>“ Solar energy systems have been tested/validated in several hinterland communities. Combined with appropriate learning tools these small systems can revolutionize Guyana’s rural educational system.” - Edward Jarvis, Field Coordinator, Ministry of Education </li></ul>
REFERENCE <ul><li>Ref: Solar energy </li></ul><ul><li>From Wikipedia, the free encyclopedia.This page was last modified on 7 March 2011 at 12:56.Retrieved on 2011-03-07 http://en.wikipedia.org/wiki/Solar_energy </li></ul><ul><li>Duncan Tom, Onac Deniz- Physics for the Caribbean: John Murray Ltd.: London: 1985 </li></ul><ul><li>Lambert norman, Samuel A. Tricia- Heinemann Physics for CXC: Heinemann Educational Publishers: Oxford:2000. </li></ul><ul><li>Rianne Hill Soriano, eHow Contributor Solar Energy Health Effects on Humans, updated: April 02, 2010retrieved on 18-03-2011< Solar Energy Health Effects on Humans | eHow.com http://www.ehow.com/list_6155201_solar-energy-health-effects-humans.html#ixzz1Gov4MiqR > </li></ul><ul><li>Sherry Barnhart, eHow Contributor , Medical Use of Ultraviolet Lights | eHow.com http://www.ehow.com/about_5185794_medical-use-ultraviolet-lights.html#ixzz1Goy9gjng </li></ul>