Analysis of Efficiency of Solar PV Cell

Analysis of Efficiency of Solar PV Cell The efficiency estimation is the most frequently method used to compare the performance of solar cells. This method can be defined as the ratio of power output from the solar cell over the irradiance power output. In addition of estimating the performance of the solar cell itself, the efficiency depends on the spectrum, intensity of sunlight and the temperature of the solar cell (Fouladi et al., 2013). The efficiency of solar cells can be estimated using the following Equation 3.15: ÃŽ · Where I is the output current, V is the voltage, A is the aperture surface area of the PV module. P is the electrical power generated, GT is the solar radiation flux on module plane (W/m2) and ÃŽ · is the cell/module electrical efficiency. The panel efficiency is effected by the cell temperature and irradiance and this effect in efficiency can by estimated by connecting the existing environment conditions to a reference condition using the following Equation 3.16 (Fouladi et al., 2013): ÃŽ ·ref is the cell efficiency at the reference temperature, Tref (typically 25 Â ºC), 1000 W/m2 is the reference solar irradiance. ÃŽ ² is the temperature coefficient and ÃŽ ³ is the solar irradiance coefficient and both coefficients depend on the PV materials. From Equation 3.16, it can be noticed that an increase in cell temperature (TC) would result in decrease in efficiency (Fouladi et al., 2013). The value of ÃŽ ³ is often assumed to be zero and Equation 3.17 will be: ÃŽ ·ref and ÃŽ ² values are given by the manufacturers. However, the can be estimated using a flash test in which the cell’s electrical output is measured at two different temperatures for given solar radiation flux (Hart and Raghuraman, 1982; Skoplaki and Palyvos, 2009). The actual value of ÃŽ ² it depends on Tref along with the dependence on PV materials and it can be given by Equation 3.18: T0 is the temperature at which the electrical efficiency of the PV module reach is zero (Garg and Agarwal, 1995; Skoplaki and Palyvos, 2009). For crystalline silicon solar cells the highest temperature in at which the PV module electricity drops to Zero is 270 Â ºC (Evans and Florschuetz, 1978; Skoplaki and Palyvos, 2009). The output voltage decreases significantly with the increase of the cell temperature and that causes the current to increase slightly. Nominal operation cell temperature method (NOCT) is used to estimate the cell temperature. This method estimates the cell temperature by measure the cell temperature of an open-rack PV module under an open circuit and in a standard reference environment Fouladi et al., 2013). The solar radiation is estimated typically to be 800W/m2 (GT, NOCT) and the PV panel is tilted 45Â º from the horizontal and exposed to 20 Â ºC air (Ta, NOCT) at 1 m/s. Equation 3.19 can be expressed as (Fouladi et al., 2013): Tc = Where UL is the thermal loss coefficient, Ta is the air temperature and GT is the irradiance on the plane of the panel. Coefficient Ï„ is the solar transmittance of glazing and coefficient ÃŽ ± is the solar absorptance of the PV layer. ÃŽ · is the electrical efficiency. According to (Duffie and Beckham, 1980; Fouladi et al., 2013), the term is negligible so Equation 3.20 will become: Tc = UL which is the overall heat loss for the panel can be estimated using the following Equation 3.20: UL = Where h is the convective heat loss coefficient and qrad is the radiation heat loss from the panel. There are other environmental factors that can influence the performance and the efficiency of the PV cells other than the temperature such as (Mekhilef et al., 2012): Dust Dust accumulation on the surface of PV panel reduces the amount of irradiance required for PV cell to reach maximum efficiency. The excessive accumulation of dust decreases the quality of the solar cells. Humidity: The effect of the humidity it is somehow comparable to the effect of the dust. The water vapor particles decreases the level of the sunlight irradiance needed for the PV panel to reach the maximum efficiency. When the PV surface becomes moist, the light is scattered either by reflection, diffraction or refraction when it comes in contact with the water droplets. Beside the environmental factors that affect the efficiency of the PV panel, there are technical factors that are based on electricity generation system that also can influence the efficiency of the module such as (Darwish et al., 2013): Effect of tilt angle: The tilt angle is one of major factors that determine the performance of the PV panels. The variation of the angle that the system is set with can control the level of the dust disposition on the glass and the amount of irradiance transmission of the plate under various weather conditions. Effect of PV Technology Photovoltaic technology is classified into two groups which are silicon crystalline and thin film. Each group of PV modules consists of different types of solar cells. These different types of solar cell vary also in their efficiencies, resistance to high temperatures and also resistance to harsh environment locations. The investigations found that a-Si performs best in dusty environment. Effect of Cleaning There are four methods to remove the dust and reduce the effect of the dust on the PV glass panel such as; (1) Natural, (2) Mechanical, (3) electro-mechanical and (4) electrostatic. The natural cleaning method is considered to be the simplest removal method because it depends on the rainfall and wind clearing. References Fouladi, F. Henshaw, P. and Ting, S. D. K. (2013): Enhancing Smart Grid realization with accurate prediction of photovoltaic performance based on weather forecast, International Journal of Environmental Studies, vol. (70), no. (5), pp. 754-764, DOI: 10.1080/00207233.2013.798497 Skoplaki, E. and Palyvos, J. A. (2009): On the temperature dependence of photovoltaic module electrical performance: A review of efficiency/power correlations, Solar Energy, vol. (83), pp. 614–624 Hart, G.W. and Raghuraman, P. (1982): Simulation of thermal aspects of residential photovoltaic systems. MIT Report DOE/ET/20279-202. Garg, H.P. and Agarwal, R .K. (1995): Some aspects of a PV/T collector/forced circulation flat plate solar water heater with solar cells. Energy Conversion and Management, vol. (36), pp. 87–99. Evans, D.L. and Florschuetz, L.W. (1978): Terrestrial concentrating photovoltaic power system studies. Solar Energy vol. (20), pp. 37–43. Duffie, J.A. and Beckman, W.A., 1980, Solar Engineering of Thermal Processes, 2nd ed. (New York: John Wiley and Sons). Mekhilef, S. Saidur, R. and Kamalisarvestani, M. (2012): Effect of dust, humidity and air velocity on efficiency of photovoltaic cells, Renewable and Sustainable Energy Reviews, vol. (16), pp. 2920-2925. Darwish, Z. A. Kazem, H. A. Sopian, K. Alghoul, M. A. and Chaichan, M. T. (2013): Impact of Some Environmental Variables with Dust on Solar Photovoltaic (PV) Performance: Review and Research Status, vol. (7), no. (4), pp. 152-159

Technology Impact on Family Time

The impact of technology on family time Nowadays technology is a part of our real life because most people have the same need that is the convenience. Although technology can provide and serve many functions and applications that support the human need but it also has an impact to our real life as well. The impact of Technology to our real life is time on family. Three technologies that have impact to family are computer, Mobile Phone, and Tablet. The static of tablet sales in U. S. on year 2011 from NPD Group they said â€Å"U. S. Tablet Sales excluding Apple Exceed 1. Million Units in First Months of 2011†,1 this is in one country, that mean tablet is a new technology which every people attend. Tablet is a device that suitable for individual person because it easy to take and easy for do a business, but if you use it in your family. You will concentrate only your tablet not attends to member in your family. The effect of this situation will decrease time and relationship on family. Therefore, if you are in the family you must use that device to make your family enjoy together or don’t use its.However, most of family still attend to tablet by doesn’t think about impacted on family time and relationship. On the other hand technology still has another device that can makes family time increasingly. Causes of computer applications are positive affected on family time. From past to present, there are many types of computer such as â€Å"Super Computer†, â€Å"Computer PC†, and â€Å"Computer Notebook†. Computer has an evolution of itself as you can see a new generation of computer has smaller size than the old computer. Even though new computer has smaller size, but functions and applications of it’s not small like size.It can do and serve many things by using functions and applications such as do transaction online, Facebook, E-mail, learning, or playing game. Due to this example, the article of Washington State Un iversity, Vancouver examines the perceived effect of computers on family time and relationships. The result said (89% perceived that the computer impacted their family relationships, 45% mostly positive impact; 24% mixed impact and 20% mostly negative impact). 2 From this article, Computer has positive impact more than negative impact.That means applications of computer not effect on family time and relationship. Communication by using mobile phone was cause on family time. The main function of mobile phone is used for communicate between 2 people. Because of mobile phone used for communicate and also support many functions like computer to make communicate easily. Things that new generation mobile phone can do more than old generation mobile phone is communicated by typing and video calling. This function is appropriate very much for communicate, so in part of family.Mobile phone was caused to makes family more talking, even though they can’t see or meet together in the hous e. To sum up, technology was caused on family time very much, because it has an advantage and disadvantage inside itself. it has an evolution all the time in term of components or applications. Therefore every family should learn and select the advantage of each technology such as use computer and tablet for learning more than playing game, or use mobile phone for participate and communicate in family more than chat to friend.If your family can do like the example your family will gain more time and reduce impact on family. ————————————————————————————————————————————– Reference 1 U. S. Tablet Sales excluding Apple Exceed 1. 2 Million Units in First Months of 2011: <http s://www. npd. com/wps/portal/npd/us/news/pressreleases/pr_111122b> 2Jane D. Lanigan, Washington State University, Vancouver <http://familyscienceassociation. org/archived%20journal%20articles/FSR_vol14_2008/2Jane_Lanigan. pdf>

The Pain of Paradox Essay Topics

The Pain of Paradox Essay Topics It is very important to get started with demonstrating the principal idea of the entire piece so you and your readers are going to be on the exact same page. With Press Buy, you'll have experiences that are the mix of effortlessness of shopping online and the assurance of to provide you a feel like purchasing from the true shop. It's especially frustrating if you haven't any idea how to compose an effective persuasive essay. Such essays shall have a good deal of quotations, based just on facts and laws, and show no more than the actual picture of the situation. Persuasive essay is also called the argument essay. For example, Write a fantastic informative essay with these very simple essay hacks. If you analyze the situation carefully, you're realize how paradoxical it's in nature. It's possible to always give more details once your listener asks for more. You need not just to possess a lot of knowledge in several fields, but in addition h ave an opportunity to construct logical connections and make conclusions. Ultimately, the previous assumption assumes an object which has been disassembled and reassembled doesn't lose its identity. The flaw supporting the paradox is in the further normative assumption which you ought to switch envelopes based upon this calculation. The entire point is all about deciding on a subject, which will present your point of view and provide you an opportunity to convince readers your statements are correct. Typically, a paradox is something which shows some contradictory qualities. The paradox is made from the simple fact that, once we fall in love, we're trying to re-find all or a few of the people to whom we were attached as children. All About Paradox Essay Topics When you get your completed essay, make certain that you tell all your friends what an excellent service it is and what's the perfect place to obtain cheap essays. The legitimate leadership essay is simple to read and understand. Occasionally, selecting an excellent argumentative essay topics will be quite tough. Following are a few of the suggested sociology essay topic for those students that are unable to decide on a great topic for their assignment. If it comes to write engineering essay for those students that are studying in electrical engineering school becomes confused since they are engineers and not the writers. Presenting The Research Paper Research papers have to be presented well to make the correct effects. Students just need to locate their niche from the multitude of topics they can explore. Life, Death, and Paradox Essay Topics Be clear in your thoughts about the point that you want to make. To be certain you are on the most suitable way you will need help in writing your paperwork. Once you pick the best topic you shall ensure it is attractive to the reader. It ought to be a topic that's easy, interesting, and at the exact time related to the function of the exercise. Essay plans can be useful in reminding you of important points that may be used to cover in your essay. To put it differently, the government will attempt to encourage savings to hamper consumption in the brief run. It will try to depress a ggregate demand and economic activity. The government is made to protect certain businesses that are in danger of submitting for bankruptcy. What Is So Fascinating About Paradox Essay Topics? According to statistics, this form of essays is among the most challenging and causes a lot of strain and nerves. Hence, you have to first understand the significance of prejudice if you need to write great essays on prejudice for the essay exams. All these topics can bring out the finest in the students since they mature into responsible adults and donate to the welfare of the country. Finding out how to compose an essay is something which will help students not just in their school and college career, but throughout their life too. Essay writing is definitely thought to be part of academic life and essay writing demands certain abilities or the area of the writer. In school, it is been made to be a part of our learning activity. The college essays must be organized in the particular format and design based on the instructions given. Perhaps, writing argumentative essays isn't that an effortless undertaking. Through the usage of postmodernism themes and literary approaches, both the movie and book had the ability to convey that absolute truth doesn't exist since it's relative, intricate, and blurred. Depending on the sort of essay, it might additionally have a summary which provides a brief of everything that's covered in the essay. Except, obviously, it isn't. So far as essay structure goes, a 4 or 5 paragraph essay based on the number of points you might want to argue is a superb start. Using Paradox Essay Topics Contemporary writers now say that today's Cinderella would need to be attractive but still be in a position to create the honor roll. The true world is too complex to comprehend and describe completely. There's something for everybody in here. In an issue of speaking, picking out persuasive essay topics is similar to telling yourself what you need to convey to the rest of earth.

My First Grade Teacher At The Age Of Five Years Essay

I began attending school at the age of five years. In those days Kindergarten had not been invented. Although I remember my first grade teacher, Miss Lillian Bush, quite well, I recollect little about the classroom activities. I remember the â€Å"Sage grass† forts, the games we played and some things I won’t mention. I have held on to a vivid image of the school house, but the education part is not that clear. My father often talked about the Oak Hill School on Blackjack Mountain. It was a one room school house; however, we were modern at Romance where I attended. We had a four room school house and a stage, â€Å"to boot.† There was a foldaway wall between two of the class room and by folding it, an auditorium was created. Miss Bush taught the Arithmetic Class aided by a â€Å"Bead Board† and most students favored that class. Her â€Å"Bead Board† had the appearance of a giant Abacus; although, I had never seen an Abacus at that time. Anyhow, my classmates and I were taught Addition, Subtraction and the Multiplication Table and enjoyed watching Miss Bush operate her â€Å"Bead Board† at the same time. And, somewhere along the way we became conscious of the difference in a day and a thousand years. A number of years beyond the first grade, these words from Peter came to my attention:, â€Å"But, beloved, do not forget this one thing, that with the Lord one day is as a thousand years, and a thousand years as one day. (II Peter 3:8) A superficial reading of that verse might cause one toShow MoreRelatedWhy I Am A Teacher933 Words   |  4 PagesWe are first taught to speak, because we need words to acquire the skill of writing, and then we are taught to write, because we need a way to express ourselves. There has to be a beginning, each and every distinct story has a beginning, but how can we find the beginning when we were incoherent of who we were? 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