Energy Stored in Capacitors

Energy Stored in Capacitors tài liệu, giáo án, bài giảng , luận văn, luận án, đồ án, bài tập lớn về tất cả các lĩnh vực...

1 SOME RENEWABLE ENERGY SOURCES IN THE ASEAN REGION & THEIR ENVIRONMENTAL IMPACTS Er Dr Adhityan Appan Technical Adviser LBW Consultants*; RJ Crocker Consultants *Blk 265, Serangoon Central Drive #02-273 Singapore 550265 Tel: +65 98003024 Fax: +65 63535248 Email: cappan@ntu.edu.sg 1.0 INTRODUCTION The use of fossil fuels indiscriminately and the damage that has been done to the environment is leaving mankind with no option but to resort to other sources of energy. Ideally these sources should be relatively easily renewable and readily available. However, special attention should be paid to ensure that they are not harmful to the environment and should in no way be cause for environmental damage in the future. The main objectives of this paper are: • to identify three main renewable energy sources that have potential and are being developed in the ASEAN region • to study recent installations and operations of such systems and their potential for creating environmental problems and • to draw conclusions on their current use and make recommendations to minimise environmental damage in the future. 2.0 MAJOR RENEWABLE RESOURCES IN THE ASEAN REGION The Asean region has a typically tropical climate which is hot and humid throughout the year. The range of temperatures is 15 to 40 o C and the average temperature is 29 o C (1). Since rainfall is largely seasonal, there are long dry periods in between. Such conditions are conducive for the effective harnessing and use of solar energy. Traditionally, in this region, solar energy has been predominantly used for heating water and drying purposes. However, penetration of solar photovoltaic (PV) systems has been growing across the region over the last ten years, where it is used mainly for electrifying rural and remote homes and villages. Most of Cambodia, the Philippines, Vietnam and some parts of Thailand have long coastal areas and also mountains from 2000 to 3000m high. These locations have been 2 identified as most suitable for the harnessing of wind energy, another renewable energy source (Cunanan, 2002). Asean countries lie mainly in the Southeast Asian region and span the equator. Since they are all under the influence of the Asiatic monsoons, they have abundant seasonal annual rainfalls in the range of 1000 to 5000 mm (2). Hence, in all these countries, there are rivers with perennial runoff. This has led to the construction and operation of hydro- electric projects varying in size from small to large to capacities (Bucta 2007, Battachary & Kumar2005). 3. ENVIRONMENTAL FACTORS AFFECTING SOME RENEWABLE ENERGY SOURCES 3.1 SOLAR ENERGY Silicon cells are still the most commonly used PV cells. Crystalline silicon cells are expected to continue as the dominant type for the next 5 to 10 years (Goetzberger, et al., 2003). The expected future trend in the PV industry is to produce more thin-film cells, which have potential for higher energy efficiency and hence lower cost per unit of electricity generated. 3.1.1 Factors influencing the Environment a. Energy: Energy is required to manufacture and install solar components and any fossil fuels used for this purpose will generate Energy Stored in Capacitors Energy Stored in Capacitors Bởi: OpenStaxCollege Most of us have seen dramatizations in which medical personnel use a defibrillator to pass an electric current through a patient’s heart to get it to beat normally (Review [link].) Often realistic in detail, the person applying the shock directs another person to “make it 400 joules this time.” The energy delivered by the defibrillator is stored in a capacitor and can be adjusted to fit the situation SI units of joules are often employed Less dramatic is the use of capacitors in microelectronics, such as certain handheld calculators, to supply energy when batteries are charged (See [link].) Capacitors are also used to supply energy for flash lamps on cameras Energy stored in the large capacitor is used to preserve the memory of an electronic calculator when its batteries are charged (credit: Kucharek, Wikimedia Commons) Energy stored in a capacitor is electrical potential energy, and it is thus related to the charge Q and voltage V on the capacitor We must be careful when applying the equation for electrical potential energy ΔPE = qΔV to a capacitor Remember that ΔPE is the potential energy of a charge q going through a voltage ΔV But the capacitor starts with zero voltage and gradually comes up to its full voltage as it is charged The first charge placed on a capacitor experiences a change in voltage ΔV = 0, since the capacitor has zero voltage when uncharged The final charge placed on a capacitor experiences ΔV = V, since the capacitor now has its full voltage V on it The average voltage on the capacitor during the charging process is V / 2, and so the average voltage experienced by the full charge q is V / Thus the energy stored in a capacitor, Ecap, is Ecap = QV , where Q is the charge on a capacitor with a voltage V applied (Note that the energy is not QV, but QV / 2.) Charge and voltage are related to the capacitance C of a capacitor 1/5 Energy Stored in Capacitors by Q = CV, and so the expression for Ecap can be algebraically manipulated into three equivalent expressions: Ecap = QV = CV2 = Q2 2C , where Q is the charge and V the voltage on a capacitor C The energy is in joules for a charge in coulombs, voltage in volts, and capacitance in farads Energy Stored in Capacitors The energy stored in a capacitor can be expressed in three ways: Ecap = QV = CV2 = Q2 2C , where Q is the charge, V is the voltage, and C is the capacitance of the capacitor The energy is in joules for a charge in coulombs, voltage in volts, and capacitance in farads In a defibrillator, the delivery of a large charge in a short burst to a set of paddles across a person’s chest can be a lifesaver The person’s heart attack might have arisen from the onset of fast, irregular beating of the heart—cardiac or ventricular fibrillation The application of a large shock of electrical energy can terminate the arrhythmia and allow the body’s pacemaker to resume normal patterns Today it is common for ambulances to carry a defibrillator, which also uses an electrocardiogram to analyze the patient’s heartbeat pattern Automated external defibrillators (AED) are found in many public places ([link]) These are designed to be used by lay persons The device automatically diagnoses the patient’s heart condition and then applies the shock with appropriate energy and waveform CPR is recommended in many cases before use of an AED 2/5 Energy Stored in Capacitors Automated external defibrillators are found in many public places These portable units provide verbal instructions for use in the important first few minutes for a person suffering a cardiac attack (credit: Owain Davies, Wikimedia Commons) Capacitance in a Heart Defibrillator A heart defibrillator delivers 4.00 × 102 J of energy by discharging a capacitor initially at 1.00 × 104 V What is its capacitance? Strategy We are given Ecap and V, and we are asked to find the capacitance C Of the three expressions in the equation for Ecap, the most convenient relationship is Ecap = CV2 Solution Solving this expression for C and entering the given values yields C = = 2Ecap V = 2(4.00×102 J) (1.00×104 V)2 = 8.00×10 – F 8.00 µF Discussion This is a fairly large, but manageable, capacitance at 1.00 × 104 V 3/5 Energy Stored in Capacitors Section Summary • Capacitors are used in a variety of devices, including defibrillators, microelectronics such as calculators, and flash lamps, to supply energy • The energy stored in a capacitor can be expressed in three ways: QV CV2 Q2 Ecap = = = 2C , where Q is the charge, V is the voltage, and C is the capacitance of the capacitor The energy is in joules when the charge is in coulombs, voltage is in volts, and capacitance is in farads Conceptual Questions How does the energy contained in a charged capacitor change when a dielectric is inserted, assuming the capacitor is isolated and its charge is constant? Does this imply that work was done? What happens to the energy stored in a capacitor ... ACTION PLAN MAKING A CHART OF THE ENERGY CONSUMPTION IN H.C.M. CITY INTRODUCTION OF GOAL INTRODUCTION OF GOAL • In new basic program of English 11.Unit 11 “sources of energy” Part D. writing: describing information from the chart. • By the end of the lesson Ss.will be able to read the information from the chart and write a description from it. • This design can help them to infinite the information in the coursebook not only realisticly but clearly as well. ASSIGNED ROLES ASSIGNED ROLES  Ss. Work in groups of four or five. Ss. Work in groups of four or five.  Each group works independently. Each group works independently.  The teacher is the monitor and the facilitator. The teacher is the monitor and the facilitator.  Every member in the group has to take part in Every member in the group has to take part in their work going to each of the family in their their work going to each of the family in their neighbour to take the notes of the amount of neighbour to take the notes of the amount of energy they spent (water, electricity, ,oil,coal…) energy they spent (water, electricity, ,oil,coal…) in a module of time or looking for from many in a module of time or looking for from many different areas (survey, geothermatics, different areas (survey, geothermatics, environment, factories) in their websites and environment, factories) in their websites and make the chart with their agreed result. make the chart with their agreed result.  All groups present their ways to do and their All groups present their ways to do and their charts in front of the class and share the best charts in front of the class and share the best way to the web site of the resources file of City way to the web site of the resources file of City education service. education service. ACTIVITIES All Ss.in each group should do their real assignement to be able to collect the own amounts of the city habitants’energy consumption for their group’s chart. Time on task : three days in maximum. In put : words and phrases in coursebook with the structure of relative clause omission. ASSESSMENT ASSESSMENT Assessment and correction Assessment and correction Marks Marks Having enough partners’ ideas Having enough partners’ ideas 5 5 Right as the ideas are led Right as the ideas are led 7 7 Completing the group’s duty Completing the group’s duty 7 7 Having the creative combination’s Having the creative combination’s ideas ideas +1 +1 Having plenty of properly Having plenty of properly illustrated pictures illustrated pictures +1 +1 Beautiful shape Beautiful shape +1 +1 CONCLUSION • Realistic knowledge is impossible without being applied for live society. • Interactive learning is impossible without pairworks and groupworks. And learning or teaching in the 21st century must always be put in the 4L situation (Learn, Live, Love and Laugh). Lớp PIL2_1 • Phan Th B yị ả THPT Trần Hữu Trang Q5 ACTION PLAN MAKING A CHART OF THE ENERGY CONSUMPTION IN H.C.M. CITY INTRODUCTION OF GOAL INTRODUCTION OF GOAL • In new basic program of English 11.Unit 11 “sources of energy” Part D. writing: describing information from the chart. • By the end of the lesson Ss.will be able to read the information from the chart and write a description from it. • This design can help them to infinite the information in the coursebook not only realisticly but clearly as well. ASSIGNED ROLES ASSIGNED ROLES  Ss. Work in groups of four or five. Ss. Work in groups of four or five.  Each group works independently. Each group works independently.  The teacher is the monitor and the facilitator. The teacher is the monitor and the facilitator.  Every member in the group has to take part in Every member in the group has to take part in their work going to each of the family in their their work going to each of the family in their neighbour to take the notes of the amount of neighbour to take the notes of the amount of energy they spent (water, electricity, ,oil,coal…) energy they spent (water, electricity, ,oil,coal…) in a module of time or looking for from many in a module of time or looking for from many different areas (survey, geothermatics, different areas (survey, geothermatics, environment, factories) in their websites and environment, factories) in their websites and make the chart with their agreed result. make the chart with their agreed result.  All groups present their ways to do and their All groups present their ways to do and their charts in front of the class and share the best charts in front of the class and share the best way to the web site of the resources file of City way to the web site of the resources file of City education service. education service. ACTIVITIES All Ss.in each group should do their real assignement to be able to collect the own amounts of the city habitants’energy consumption for their group’s chart. Time on task : three days in maximum. In put : words and phrases in coursebook with the structure of relative clause omission. ASSESSMENT ASSESSMENT Assessment and correction Assessment and correction Marks Marks Having enough partners’ ideas Having enough partners’ ideas 5 5 Right as the ideas are led Right as the ideas are led 7 7 Completing the group’s duty Completing the group’s duty 7 7 Having the creative combination’s Having the creative combination’s ideas ideas +1 +1 Having plenty of properly Having plenty of properly illustrated pictures illustrated pictures +1 +1 Beautiful shape Beautiful shape +1 +1 CONCLUSION • Realistic knowledge is impossible without being applied for live society. • Interactive learning is impossible without pairworks and groupworks. And learning or teaching in the 21st century must always be put in the 4L situation (Learn, Live, Love and Laugh). Lớp PIL2_1 • Phan Th B yị ả THPT Trần Hữu Trang Q5 I NTERNATIONAL J OURNAL OF E NERGY AND E NVIRONMENT Volume 2, Issue 5, 2011 pp.771-782 Journal homepage: www.IJEE.IEEFoundation.org ISSN 2076-2895 (Print), ISSN 2076-2909 (Online) ©2011 International Energy & Environment Foundation. All rights reserved. Prospects of concentrating solar power to deliver key energy services in a developing country Charikleia Karakosta, Charalampos Pappas, John Psarras National Technical University of Athens, School of Electrical and Computer Engineering, Management & Decision Support Systems Lab (NTUA-EPU), 9, Iroon Polytechniou str., 15780, Athens, Greece. Abstract One of today’s greatest challenges is the response to the worldwide continuously increasing energy demand. The need for supply of electricity is getting greater year by year. In addition, climate change problems and the limited fossil resources require new sustainable electricity generation options, which utilize Renewable Energy Sources (RES) and are economical in the meantime. Concentrating Solar Power (CSP) generation is a proven renewable energy technology that has the potential to become cost- effective in the future. This analysis explores for Chile the potential of CSP to deliver key energy services for the country. The specific technology has a significant technical potential within Chile, but ‘somehow’ do not receive sufficient attention from relevant stakeholders, because of gaps either in stakeholders’ awareness of the technology or in domestic research and development (R&D) and/or public/private investment. The aim of this paper is to establish a well-informed discussion on the feasibility and potential of the specific sustainable energy technology, namely the CSP technology, within a given country context and particularly Chile. It provides an overview of the fundamental (macro-economic) forces within an economy and identifies some of the blockages and barriers that can be expected when introducing a new technology. Copyright © 2011 International Energy and Environment Foundation - All rights reserved. Keywords: Renewable energy; Potential; Concentrated solar power; Sustainable development; Chile. 1. Introduction Global warming is considered as one of the most critical problems that the environment would be faced with, in the next fifty years [1]. The use of Renewable Energy Sources (RES) is a fundamental factor for a possible energy policy in the future. In addition, Sustainable Development (SD) has acquired great importance due to the negative impact of various developments on environment. Taking into account the sustainable character of the majority of renewable energy technologies, they are able to preserve resources and to provide security, diversity of energy supply and services, virtually without environmental impact. Generating electricity from RES represents a promising option. Despite its today’s costs, increasing the supply of electricity from RES helps to reduce high dependence on imported energy and provides invaluable environmental benefits with regards to Greenhouse Gas (GHG) emissions, thus playing an important role in mitigating climate change [2]. Therefore, promoting innovative renewable applications and reinforcing the renewable energy market will contribute to preservation of the ecosystem by reducing emissions at local and global levels. International Journal of Energy and Environment (IJEE), Volume 2, Issue I NTERNATIONAL J OURNAL OF E NERGY AND E NVIRONMENT Volume 2, Issue 1, 2011 pp.71-84 Journal homepage: www.IJEE.IEEFoundation.org ISSN 2076-2895 (Print), ISSN 2076-2909 (Online) ©2011 International Energy & Environment Foundation. All rights reserved. Review and analysis of renewable energy perspectives in Serbia Charikleia Karakosta, Haris Doukas, Maria Flouri, Stamatia Dimopoulou, Alexandra G. Papadopoulou, John Psarras National Technical University of Athens, School of Electrical and Computer Engineering, Management & Decision Support Systems Lab (NTUA-EPU), 9, Iroon Polytechniou str., 157 80, Athens, Greece. Abstract Nowadays, Serbia needs to disengage from the broad use of fossil fuels and turn to the “attractive” Renewable Energy Sources (RES) for energy production, since the Kyoto Protocol ratification, so as to resolve systematically the problem of energy demand. In addition, research indicates that Serbia is a country with high potential and favourable conditions for RES energy production, as the country’s potential could supply almost half of its primary energy needs. The paper provides an overview of Serbia’s energy sector status quo, so as to emphasize the necessity for RES implementation in order to balance the country’s energy deficit. The aim is to investigate and present the country’s prospects in the RES sector, revealing the proven RES potential and pointing out that the unexploited RES potential together with an adequately well structured energy sector would create great possibilities and conditions for a new market. Copyright © 2011 International Energy and Environment Foundation - All rights reserved. Keywords: Energy sector, Renewable energy sources, Serbia. 1. Introduction The Republic of Serbia is located in South-Eastern Europe, in the heart of the Balkan Peninsula. The country of Serbia is characterized by an energy deficit, which continues to grow. Serbia is an energy- wise medium-dependent country, as the annual consumption of all types of energy is greater than the domestic production, with a total dependence of around 40% [1]. After the institutional changes occurring in the year 2000, Serbia initiated an ambitious program aiming in the reform and stabilization in all sectors, also including the energy sector. Within this framework, in 2004 the country adopted the Energy Law, while in 2005, the Ministry of Mining and Energy (MoME) developed the Energy Development Strategy up to 2015. In 2007, Serbia ratified the Kyoto Protocol, taking over the responsibility to increase the portion of energy produced from Renewable Energy Sources (RES) up to 20% until 2012 [2]. Moreover, in line with the Energy Law and the Strategy, the MoME prepared the Energy Strategy Implementation Programme - ESIP 2007–2012, which defined conditions, methods and time schedule for the implementation of the Strategy in all the major parts of the energy sector. Towards this direction, among the priorities of Serbia’s energy policy in the near future, as foreseen by the Energy Development Strategy up to 2015, are to exploit RES, including biomass, geothermal, solar, and wind power, as well as to retain hydroelectric potentials which, utilization is technically possible and International Journal of Energy and Environment (IJEE), Volume 2, Issue 1, 2011, pp.71-84 ISSN 2076-2895 ... capacitor C The energy is in joules for a charge in coulombs, voltage in volts, and capacitance in farads Energy Stored in Capacitors The energy stored in a capacitor can be expressed in three ways:... 3/5 Energy Stored in Capacitors Section Summary • Capacitors are used in a variety of devices, including defibrillators, microelectronics such as calculators, and flash lamps, to supply energy. .. 7.40 μF capacitor (a) Find the charge and energy stored if the capacitors are connected to the battery in series (b) Do the same for a parallel connection 4/5 Energy Stored in Capacitors (a) 1.42