The Power of the Sun By Anna and Gloria

First Discovery and Use The Greeks and Romans were probably the first people to discover the power of the sun and put that energy to use. Edmund Becquerel discovered the photovoltaic effect in 1839 wile experimenting with the electrolytic cell. Russell Ohl was the first person to find a way to harness the sun’s energy when he invented the solar cell in Gerald Pearson, Calvin Fuller and Daryl Chapin worked together to invent the first efficient solar panels.

When and where is was first used The sun’s energy was first used in about 400 BC in Greece and Rome. After Ohl discovered how to harness the sun’s energy through solar cells, satellites in space began to use them to produce electricity. The efficient solar battery was first used in a telephone carrier system in Americus, Georgia on October 4, 1955

Why? The Romans and Greeks developed the use of the sun’s energy to heat buildings and water. The Greeks also used it to grow vegetables in greenhouses. Solar cells were first used to provide electricity for satellites and when cheaper alternatives were unavailable.

How? The Greeks and Romans discovered that by building their houses a certain way would trap the heat inside and making darker colored pots would keep the contents warmer for longer. Pearson, Fuller and Chapin put several strips of silicon the size of razorblades in the sunlight and captured the free electrons and turned them into an electrical current.

Diagram- Water

Diagram- Electricity

Steps of Solar energy production The sun hits the solar panels Solar panels collect energy from the sun The collected solar energy is sent to the electric panel The electric panel provides electricity for the building Excess energy can be sold to the power company

Current Uses Heat –Passive: Air is circulated past the solar heat surface and through the building by convection. –Active: A “collector” absorbs and collects solar radiation. Fans or pumps circulate the heated air. Electricity –Thermal power plants Parabolic trough: focuses the sun’s rays on a receiver pipe and moves with the sun as the day progresses Solar dish: tracks the sun and points straight at it to receive concentrated solar energy Solar power tower: focuses concentrated solar energy gathered by rotating mirrors on a tower- mounted heat exchanger/ receiver

Where is it currently used? Residential and business buildings Vehicles Roadway signs Heating water Creating portable water

Future Plans Storing excess energy Creating a miniature “sun” on earth to help power solar cells when the sun is not shining

Benefits It is renewable, which means it can never run out. It is environmentally friendly because solar cells don’t produce pollutants. Solar cells don’t make noise. It is cheaper than electricity. There is a large variety of solar panel systems available. Can sell the excess electricity produced by the solar cells. Government will provide a tax credit or incentive for purchasing solar energy systems.

Disadvantages The initial cost of the equipment used to harness the sun’s energy Large areas are needed for the equipment in order for the system to be efficient. This is inconvenient for people that live in areas where there is not a lot of space, or where space is expensive, such as inner cities. Pollution can degrade the efficiency of photovoltaic cells Solar panels only work when the sun is shining. This means that when it is cloudy or nighttime the solar panels are less effective. The location of solar panels can affect performance, due to possible obstructions such as buildings or the landscape. Toxic materials, chemicals, solvents and alcohols that are produced in the process of making PV cells Large solar thermal power plants harm desert ecosystems if they are not properly managed. Birds and insects can be killed if they fly into a concentrated beam of sunlight produced by the “solar power tower”

References ideas.com/articles/disadvantages_of_solar_energy.html ideas.com/articles/disadvantages_of_solar_energy.html y/history.htm y/history.htm used-today-and-what-are-the-plans-for-the-future html used-today-and-what-are-the-plans-for-the-future html

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