SOLAR ENERGY
LESSON 2
Photosynthesis
Photosynthesis is the natural process thorugh which plants use the energy derined from the sunlight to produce sugar , this sugar is converted into ATP through cellular respiration, ATP is the fuel used by all the living things. The main component involved in the conversion of unusable sunlight energy into usable chemical energy is the green pigment chlorophyll. The photosynthetic processes release life sustaining oxygen and consume water.
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We can write the overall reaction of this process as:
The above chemical equation translates as:
six molecules of water plus six molecules of carbon dioxide produce one molecule of sugar plus six molecules of oxygen
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Water Heating Systems:
Solar energy can be used in water heating systems to heat water which can be used for domestic purposes such as bathing, washing dishes, laundry, or heating swimming pools. Water stored in tanks exposed to the sun is preheated by the sun before it goes into a storage tank inside the house. One of the main advantages of having solar pre heated water is that only small amount of electricity or gas is needed to raised the temperature of the water to a required level. Also many times, Cold water may be necessary to bring down the temperature of the hot water to a required level.
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Flat panel solar water heating systems:
Among the most popular type of solar collected water heating systems are the flat panel solar water heating systems. They consist of an insulated weatherproof enclosure with an absorber plate , flow tubes and a transparent cover.the transparent cover facilitates the solar energy to pass through and be absorbed by the absorber and flow tubes. This heat is then transferred to the fluid circulating through the flow tubes (A non –toxic propulene glycol-water antifreeze mixture) and pumped to a storage tank. Here the heat exchangers transfer the heat from the fluid to the household water.