Question

No excuse for energy misuse essay

Answer 1

These days, solar energy has been the most talkative alternative energy source in the world. Unlike the gas, oil, and coal, solar enrgy is one of the clean and renewable resource, which can not only generate power but also protect the environment. Africa, has second largest population, estimated 1.6 billion, however, around one third of it’s people still live in the condition with no eletricity. (Renewable energy in Africa, 2012) Fortunetly, Solar power technology bring a hope for their life , especially for those living in rural areas. In this paper, first, I will discuss the solar technologies used in Africa and the science behind these methods. Second, I am going to compare the advantages and disadvantages of solar energy. Finally, I will conclude that solar energy is a viable resource in Africa. There are two best known approaches for directly generating power from the sunlight, which are photovoltaic (PV) generation and solar thermal technologies. PV generation technology is mostly used to transfer solar energy into eletrical energy for lighting in Africa. The principle behind PV was found in 1887 by Heinrich Hertz and illustrated in 1905 by Albert Einstein. PV systems are established by solar cells. And these cells are normally made by combining two very thin crystalline silicon, in which one of them produces n-type (negative) 

Answer 2

Hey friend here is ur query...


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The solar energy use in Africa

These days, solar energy has been the most talkative alternative energy source in the world. Unlike the gas, oil, and coal, solar enrgy is one of the clean and renewable resource, which can not only generate power but also protect the environment. Africa, has second largest population, estimated 1.6 billion, however, around one third of it’s people still live in the condition with no eletricity. (Renewable energy in Africa, 2012) Fortunetly, Solar power technology bring a hope for their life , especially for those living in rural areas. In this paper, first, I will discuss the solar technologies used in Africa and the science behind these methods. Second, I am going to compare the advantages and disadvantages of solar energy. Finally, I will conclude that solar energy is a viable resource in Africa. There are two best known approaches for directly generating power from the sunlight, which are photovoltaic (PV) generation and solar thermal technologies. PV generation technology is mostly used to transfer solar energy into eletrical energy for lighting in Africa. The principle behind PV was found in 1887 by Heinrich Hertz and illustrated in 1905 by Albert Einstein. PV systems are established by solar cells. And these cells are normally made by combining two very thin crystalline silicon, in which one of them produces n-type (negative) semiconductor and the other one produces p-type (positive) semiconductor. And the conbination of these two semiconductor form a p-n junction.This junction can prevent the flow of addtional electrical charge. Therefore, when the sunlight strikes on the solar cell, it will creat a chemical effect in the p-n junction and release the electrons. This is called photoelectric effect. As shown in Figure 12.3 and Figure 12.4 , if the solar cell is conneted to an external circuit, as long as the photoelectric effect is created, it generates the eletric current and the lamp will then be lighten up. Also stated by Hinrichs and Kleinbach,“Under bright sunlight of 1000 W/m2, a current of about 100 milliamps per cm2 of cell surface area is produced by typical single-crystal cells. A cell 10 cm in diameter will produce about 1 W under insolation of 1000 W/m2. ”(2011 , p. 379) Moreover, cost of PV cells has decreased to about $0.25 to $0.30/kWh. (2011, p. 367) As a result, Solar energy can be used by more and more African, expecially for those in lower-medium income families. This technology changes the quality of life for those who live in remote area and cannot directly accessed to eletricity before. Another well known method for harnessing solar power is solar-thermal technology. This technology transfers the solar energy into thermal energy. It is especially useful in sun-rich countries. As stated in Renewable energy in Africa, an article of wikipedia, the insolation of most African countries is very sufficient, average 325 days per year of bright sunlight. ( 2012) Consequently, solar thermal technology can do a significant job in helping Africa to solve one of their main problem—cooking in rural area. Accroding to Solar Cooker International (SCI), a non-profit organzation promising to bring the solar cooking to whom in need in worldwilde, there are three major types of solar thermal devices in the world, which are pannel, box and parabolic solar cookers. And the cheapest and most popular one using in rural Africa is pannel cooker, called Cookit. (How Solar Cookers Work, 2010) The Cookit is normally made of cardboard and foil shaped. This combination can maximaize the reflection of sunlight onto a black cooking pot. When the sunlight hits the pot, the power energy is transfered into heat energy. Moreover, there are always a heat-resistant bag covering the pot to track the heat from escaping, which is also known as an example of greenhouse effect.

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