Showing papers on "Solar power published in 2004"
TL;DR: The current status of the field of organic solar cells and the important parameters to improve their performance are discussed in this paper. But, the two competitive production techniques used today are either wet solution processing or dry thermal evaporation of the organic constituents.
Abstract: Organic solar cell research has developed during the past 30 years, but especially in the last decade it has attracted scientific and economic interest triggered by a rapid increase in power conversion efficiencies. This was achieved by the introduction of new materials, improved materials engineering, and more sophisticated device structures. Today, solar power conversion efficiencies in excess of 3% have been accomplished with several device concepts. Though efficiencies of these thin-film organicdevices have not yet reached those of their inorganic counterparts (η ≈ 10–20%); the perspective of cheap production (employing, e.g., roll-to-roll processes) drives the development of organic photovoltaic devices further in a dynamic way. The two competitive production techniques used today are either wet solution processing or dry thermal evaporation of the organic constituents. The field of organic solar cells profited well from the development of light-emitting diodes based on similar technologies, which have entered the market recently. We review here the current status of the field of organic solar cells and discuss different production technologies as well as study the important parameters to improve their performance.
2,492 citations
Book•
01 Jan 2004TL;DR: In this article, the authors present an overview of the early history of the electric power industry, including the early pioneers of the electrical power industry and the development of the modern electric power system.
Abstract: Preface.1 Basic Electric and Magnetic Circuits.1.1 Introduction to Electric Circuits.1.2 Definitions of Key Electrical Quantities.1.3 Idealized Voltage and Current Sources.1.4 Electrical Resistance.1.5 Capacitance.1.6 Magnetic Circuits.1.7 Inductance.1.8 Transformers.2 Fundamentals of Electric Power.2.1 Effective Values of Voltage and Current.2.2 Idealized Components Subjected to Sinusoidal Voltages.2.3 Power Factor.2.4 The Power Triangle and Power Factor Correction.2.5 Three-Wire, Single-Phase Residential Wiring.2.6 Three-Phase Systems.2.7 Power Supplies.2.8 Power Quality.3 The Electric Power Industry.3.1 The Early Pioneers: Edison, Westinghouse, and Insull.3.2 The Electric Utility Industry Today.3.3 Polyphase Synchronous Generators.3.4 Carnot Efficiency for Heat Engines.3.5 Steam-Cycle Power Plants.3.6 Combustion Gas Turbines.3.7 Combined-Cycle Power Plants.3.8 Gas Turbines and Combined-Cycle Cogeneration.3.9 Baseload, Intermediate and Peaking Power Plants.3.10 Transmission and Distribution.3.11 The Regulatory Side of Electric Power.3.12 The Emergence of Competitive Markets.4 Distributed Generation.4.1 Electricity Generation in Transition.4.2 Distributed Generation with Fossil Fuels.4.3 Concentrating Solar Power (CSP) Technologies.4.4 Biomass for Electricity.4.5 Micro-Hydropower Systems.4.6 Fuel Cells.4.6.7 Electrical Characteristics of Real Fuel Cells.4.6.8 Types of Fuel Cells.4.6.9 Hydrogen Production.5 Economics of Distributed Resources.5.1 Distributed Resources (DR).5.2 Electric Utility Rate Structures.5.3 Energy Economics.5.4 Energy Conservation Supply Curves.5.5 Combined Heat and Power (CHP).5.6 Cooling, Heating, and Cogeneration.5.7 Distributed Benefits.5.8 Integrated Resource Planning (IRP) and Demand-Side Management (DSM).6 Wind Power Systems.6.1 Historical Development of Wind Power.6.2 Types of Wind Turbines.6.3 Power in the Wind.6.4 Impact of Tower Height.6.5 Maximum Rotor Efficiency.6.6 Wind Turbine Generators.6.7 Speed Control for Maximum Power.6.8 Average Power in the Wind.6.9 Simple Estimates of Wind Turbine Energy.6.10 Specific Wind Turbine Performance Calculations.6.11 Wind Turbine Economics.7 The Solar Resource.7.1 The Solar Spectrum.7.2 The Earth's Orbit.7.3 Altitude Angle of the Sun at Solar Noon.7.4 Solar Position at any Time of Day.7.5 Sun Path Diagrams for Shading Analysis.7.6 Solar Time and Civil (Clock) Time.7.7 Sunrise and Sunset.7.8 Clear Sky Direct-Beam Radiation.7.9 Total Clear Sky Insolation on a Collecting Surface.7.10 Monthly Clear-Sky Insolation.7.11 Solar Radiation Measurements.7.12 Average Monthly Insolation.8 Photovoltaic Materials and Electrical Characteristics.8.1 Introduction.8.2 Basic Semiconductor Physics.8.3 A Generic Photovoltaic Cell.8.4 From Cells to Modules to Arrays.8.5 The PV I -V Curve Under Standard Test Conditions (STC).8.6 Impacts of Temperature and Insolation on I -V Curves.8.7 Shading impacts on I-V curves.8.8 Crystalline Silicon Technologies.8.9 Thin-Film Photovoltaics.9 Photovoltaic Systems.9.1 Introduction to the Major Photovoltaic System Types.9.2 Current-Voltage Curves for Loads.9.3 Grid-Connected Systems.9.4 Grid-Connected PV System Economics.9.5 Stand-Alone PV Systems.9.6 PV-Powered Water Pumping.APPENDIX A: Useful Conversion Factors.APPENDIX B: Sun-Path Diagrams.APPENDIX C: Hourly Clear-Sky Insolation Tables.APPENDIX D: Monthly Clear-Sky Insolation Tables.APPENDIX E: Solar Insolation Tables byCity.APPENDIX F: Maps of Solar Insolation.Index.
1,884 citations
TL;DR: In this article, an engineering study was carried out to evaluate a concept where another (less expensive) liquid medium such as molten salt is utilized as storage medium rather than the heat transfer fluid (HTF) itself.
543 citations
Book•
01 Jan 2004
TL;DR: The second edition of the book as mentioned in this paper has been published and a considerable amount of new information, along with computational tools has been added in this edition, including new data files on measured data sets of irradiance and illuminance.
Abstract: Preface
Rapid sale of the first edition in a relatively short time plus the need to update information
for an area of significant activity has dictated the need for the second edition of this
book. Of late, the rapid deployment of solar photovoltaic technology across the globe has
also demanded a need for the estimation of the local availability of the solar energy
resource. In this respect the user will find that a considerable amount of new information,
along with computational tools has been added in this edition.
New material and, in most cases, resulting computer programs on the following topics
has been provided:
(a) Sun-path diagrams for abbreviated analysis.
(b) New data files on measured data sets of irradiance and illuminance.
(c) Distance between any two locations (solar radiation measurement site and location
of its utilisation).
(d) Characterisation of sky clarity indices and solar climate for any given location.
(e) Corrections for sky-diffuse irradiance measurements using a shade-ring device.
(f) Quality control of measured solar radiation and daylight data including outlier
analysis.
(g) Cloud radiation model.
(h) Page radiation model (developed by Emeritus Professor John Page).
(i) An extensive section on various forms of turbidity and their inter-relationships.
(j) Newer generation of turbidity-based radiation models.
(k) The European clear-sky solar radiation model (developed by Emeritus Professor
John Page).
(l) Procedures for obtaining sunshine data from cloud cover information and vice versa.
(m) Frequency of occurrence of diffuse and global illuminance.
(n) Zenith luminance models.
(o) New all-sky CIE standard for sky luminance distribution.
(p) Spectral radiation.
(q) Detailed measured data sets of solar radiation and other meteorological parameters.
(r) Web sites that provide solar radiation and daylight data and other related information.
In response to a demand from readers and reviewers of this book a section on estimation
of clear-sky solar irradiance for any part of the globe has been added.
Within the past 5 years there has been an acceleration of activity in the exploitation of
solar energy and this has primarily resulted from protection of environment pressures. The
Kyoto protocol for reduction of carbon dioxide has been an important instrument in this
respect. Subsidies offered for the use of solar water heating and building integrated photovoltaic
installations (BIPV technology) within the European Union countries have resulted in a rapid take-off of these and related technologies.
Another contributing factor that will eventually lead to the use of solar power within the
transport sector is the spiralling monetary and environment costs associated with the current
use of fossil fuels. With the rapid decline in the oil reserves within the Gulf of Mexico
basin, Iraq has become the linchpin in the US strategy to secure cheap oil. Between Saudi
Arabia and Iraq, with their respective proven oil reserves of 262 and 112 billion barrels, a
staggering 40% of world’s oil reserves is shared. With the US invasion of Iraq it appears that
a new phase of ‘Energy wars’ has started that may indeed spill over to other Opec countries.
The repercussions of such actions and the fact that cheaper oil resulting from the ‘capture’
of oil reserves will lead to a faster consumption may indeed herald the true age of solar
energy. In this respect world political leaders would be well advised to promote renewable
energy technologies. That is the only and truly sustainable action for the abatement of the
effects of an increase in atmospheric greenhouse gas loading.
332 citations
TL;DR: In this article, the authors provide a comprehensive overview of solar energy sources and conversion methods and their potential application in future electric energy generation based on solar power site-exploitation and transmission by different means such as fiber-optic cables.
255 citations
TL;DR: In this paper, the results of a collaborative effort under the International Energy Agency SolarPACES organization to address these questions and it shows the potential environmental and economic benefits of each configuration.
227 citations
01 Nov 2004
TL;DR: In this article, the authors presented an analysis of the combined cycle operation of a solid oxide fuel cell (SOFC)-microturbine and a strategy for combining the thermophotovoltaic power generation unit and SOFC to obtain the hybrid power system that would have higher efficiency.
Abstract: A hybrid power system consists of a combination of two or more power generation technologies to make best use of their operating characteristics and to obtain efficiencies higher than that could be obtained from a single power source. Since fuel cells directly convert fuel and an oxidant into electricity through an electrochemical process, they produce very low emissions and have higher operating efficiencies. Hence, combining fuel cells with other sources, the efficiency of the combined system can be further increased or extend the duration of the available power to the load as a backup power. In this paper, different types of fuel-cell hybrid systems and their applications are presented. An analysis of the combined cycle operation of a solid oxide fuel cell (SOFC)-microturbine is presented. A strategy for combining the thermophotovoltaic power generation unit and SOFC to obtain the hybrid power system that would have higher efficiency is proposed. The hybrid operation of wind power and solar power system with proton exchange membrane fuel cell is also presented.
218 citations
28 Jun 2004
TL;DR: This work proposes to utilize solar power in wireless sensor networks and extend LEACH a well-known cluster-based protocol for sensor networks to become solar-aware, showing that making LEACH solar- aware significantly extends the lifetime of sensor networks.
Abstract: Energy conservation plays a crucial in wireless sensor networks since such networks are designed to be placed in hostile and nonaccessible areas While battery-driven sensors will run out of battery sooner or later, the use of renewable energy sources such as solar power or gravitation may extend the lifetime of a sensor network We propose to utilize solar power in wireless sensor networks and extend LEACH a well-known cluster-based protocol for sensor networks to become solar-aware The presented simulation results show that making LEACH solar-aware significantly extends the lifetime of sensor networks
168 citations
TL;DR: In this article, an experimental solar-driven ammonia-based closed-loop thermochemical energy storage system using a cavity receiver containing 20 reactor tubes filled with iron-based catalyst material, which collects the radiation from a 20 m2 dish solar concentrator was demonstrated.
167 citations
TL;DR: In this article, the authors explore the combined effects of radiative and solar wind fluctuations at Earth and estimate the relative contributions of solar extreme ultraviolet (UV) power, Joule power, and particle kinetic power to the Earth's upper atmosphere energy budget.
Abstract: Solar variability is often cast in terms of radiative emission and the associated long-term climate response; however, growing societal reliance on technology is creating more interest in day-to-day solar variability. This variability is associated with both solar radiative and solar wind emissions. In this paper we explore the combined effects of radiative and solar wind fluctuations at Earth. The fluctuations in radiative and geomagnetic power create an extended interval of solar maximum for the upper atmosphere. We use a trio of empirical models to estimate, over the last three solar cycles, the relative contributions of solar extreme ultraviolet (UV) power, Joule power, and particle kinetic power to the Earth’s upper atmosphere energy budget. Daily power values are derived from three source models. The SOLAR2000 solar irradiance specification model provides estimates of the daily extreme and far UV solar power input. Geomagnetic power is derived from a combination of satellite-estimated particle precipitation power and an empirical model of Joule power from hemispherically integrated estimates of high-latitude energy deposition. During the interval 1975 to 2003, the average daily contributions were: particles – 36 GW, Joule – 95 GW and solar – 464 GW for a total of 595 GW. Solar wind-driven geomagnetic power provided 22% of the total global upper atmospheric energy. In the top 15 power events, geomagnetic power contributed two-thirds of the total power budget. In each of these events, Joule power alone exceeded solar power. With rising activity, Joule power becomes the most variable element of solar upper atmosphere interactions.
TL;DR: In this paper, a real-time simulation method for PV generation systems under real weather conditions using a realtime digital simulator (RTDS) is proposed, and the results of the simulation demonstrate the effectiveness of the proposed simulation technique, and also show that cost effective verification of availability and stability of PV generation system is possible using the built-in simulator.
Abstract: For the performance test of photovoltaic (PV) generation systems, actual system apparatuses: a solar panel, converter system, and load facilities should be installed. It is also hardly possible to compare a maximum power point tracking (MPPT) control scheme with others under the same weather and load conditions in an actual PV generation system. One of the possible alternatives is to realize a transient simulation scheme for PV generation systems under real weather conditions of insolation and surface temperature of solar cell. The authors propose a novel real-time simulation method for PV generation systems under real weather conditions using a real-time digital simulator (RTDS). V--I curves of a real PV panel are tested using electric load device, and a hypothetical network of the tested PV panel is created on the RTDS by arranging electrical components from the customized component model libraries. The real weather conditions, insolation, and temperature of the PV panel, are interfaced through the analog input ports of the RTDS for real-time simulation. The outcomes of the simulation demonstrate the effectiveness of the proposed simulation technique, and also show that cost-effective verification of availability and stability of PV generation systems is possible using the built-in simulator.
Patent•
19 Nov 2004TL;DR: In this paper, a solar cell assembly including a plurality of solar cells is formed on a common substrate, and a DC/DC converter which converts the output from the solar cell is connected to each solar cell to constitute a solar power generation apparatus.
Abstract: A solar cell assembly including a plurality of solar cells is formed on a common substrate, and a DC/DC converter which converts the output from the solar cell is connected to each solar cell to constitute a solar power generation apparatus. The output from the solar power generation apparatus is converted into an AC power by an inverter and supplied to a load or commercial AC power system. Since the arrangement is simplified, the manufacturing cost can be reduced, and the influence of partial shade or a variation in characteristic decreases.
20 Jun 2004
TL;DR: In this paper, the authors proposed a new optimum operating point tracker of the solar cell power supply system, in which inexpensive pn-junction diodes are used to generate the reference voltage of the operating point of a solar array.
Abstract: When the solar array is used as an input power source, the optimum operating point tracker is often employed to exploit more effectively the solar array as an electric power source and to obtain the maximum electric power at all times even when the light intensity and environmental temperature of the solar array are varied. Usually, the optimum operating point is determined by computing the electric power from the solar array power supply with a microcomputer, DSP and so forth. However, such a method has the problems of the complex control circuit configuration, high cost and low control speed. From this viewpoint, this paper proposes a new optimum operating point tracker of the solar cell power supply system, in which inexpensive pn-junction diodes are used to generate the reference voltage of the operating point of the solar array. Using the proposed method, the high degree of the solar array optimum point tracking performance can be obtained, even when the light intensity and environmental temperature of the solar array are varied. Furthermore, the proceeding paper provides the operation principle, design-oriented analysis and so forth, of the proposed solar cell power supply system.
Patent•
08 Mar 2004
TL;DR: In this article, a tracking solar power array that provides shelter to items disposed beneath the solar power arrays, particularly to vehicles, is presented, where the array is equipped with a thermal sensor.
Abstract: The present invention comprises a tracking solar power array that provides shelter to items disposed beneath the solar power array, particularly to vehicles.
TL;DR: In this paper, the authors present a perspective on the production and use of hydrogen as an automotive fuel, and discuss the sources of hydrogen in the near and long-term future as well as the cost of hydrogen production.
Abstract: This work presents a perspective on the production and use of hydrogen as an automotive fuel. Hydrogen has been hailed as the key to a clean energy future primarily because it can be produced from a variety of energy sources, it satisfies all energy needs, it is the least polluting, and it is the perfect carrier for solar energy in that it affords solar energy a storage medium. Efforts are underway to transform the global transportation energy economy from one dependent on oil to that based on sustainable hydrogen. The rationale behind these efforts is that hydrocarbon-based automobiles are a significant source of air pollution, while hydrogen-powered fuel cell vehicles produce effectively zero emissions. Besides the transportation area, fuel cells can also reduce emissions in other applications such as the residential or commercial distributed electricity generation. Hydrogen is the perfect partner for electricity, and together they create an integrated energy system based on distributed power generation and use. A discussion on the sources of hydrogen in the near- and long-term future as well as the cost of hydrogen production is provided.
Patent•
21 May 2004TL;DR: In this article, a wireless power and communication unit for field devices is configured to connect to a field device and provide operating power and wired digital communication between the unit and the field device.
Abstract: A wireless power and communication unit for field devices is configured to connect to a field device and provide operating power and wired digital communication between the unit and the field device. RF circuitry in the unit is configured for radio frequency communication. In one embodiment, power supply circuitry in the unit includes one or more solar power cells that convert solar energy into electricity to power both the unit and the field device. The unit interacts with the field device in accordance with a standard industry communication protocol. The unit communicates wirelessly with an external device, such as a control room, based upon the interaction with the field device.
TL;DR: In this article, the authors present a procedure to estimate the required dimension of a photovoltaic installation designed to power a pumping system for the drip irrigation of an olive tree orchard in SW Spain.
TL;DR: In this article, the authors proposed a 10 MWe solar power plant PS10, which is based on the atmospheric air circuit technology, and used a regenerative thermal storage unit to supply hot air to the steam generator, until the solar power returns or a controlled plant shutdown is performed.
TL;DR: In this paper, a hybrid heat flux measurement system was designed, built and mounted on top of the SSPS-CRS tower at the Plataforma Solar de Almeria (PSA) to measure the incident solar power that is concentrated by a heliostat field on the flat aperture of a central receiver.
01 Jan 2004
09 Aug 2004
TL;DR: In this paper, a source-tracking power management strategy that maximizes the panel's total energy output under a given solar profile by load matching was proposed, and the power efficiency was validated by extensive measurement.
Abstract: Solar power is an important source of renewable energy for many low-power systems. Matching the power consumption level with the supply level can make a great difference in the efficiency of power utilization. This paper proposes a source-tracking power management strategy that maximizes the panel's total energy output under a given solar profile by load matching. The power efficiency was validated by extensive measurement. Compared to a conventional solar powered system, our load matching strategy improves the power utilization by 132% for a portable system performing image processing and wireless communication tasks.
TL;DR: In this article, an improved MPPT algorithm was proposed to reduce the power loss in the tracking process and a digital signal processor (DSP) based controller was constructed to implement the proposed MPPT control, and the experimental results are presented.
TL;DR: In this article, a theoretical model was used to predict the electrical power output by Gallium Arsenide/Germanium solar cells at the surface of Mars using measurements from the Mars Pathfinder Lander.
Patent•
25 Aug 2004TL;DR: In this paper, a solar power generation system having a solar cell provided therein and which is provided with a cooling mechanism, characterized in that the cooling mechanism has a cooling system for cooling the solar cell and a memory and operation system for memorizing or operating an optimum cooling and driving state of the cooling system with respect to an output of the solar cells.
Abstract: A solar power generation system having a solar cell provided therein and which is provided with a cooling mechanism, characterized in that the cooling mechanism has a cooling system for cooling the solar cell and a memory and operation system for memorizing or operating an optimum cooling and driving state of the cooling system with respect to an output of the solar cell. The cooling system is driven based on an output of the memory and operation system.
Patent•
25 Mar 2004
TL;DR: In this article, the authors proposed a power conversion apparatus for solar power generations with a plurality of solar battery modules 8a, 8b, 8c serving as the power source, boost chopper parts 26a, 26b, 26c for performing maximum power follow-up of each solar battery module 8a.
Abstract: PROBLEM TO BE SOLVED: To attain improvement of system power generation efficiency by independently performing maximum power follow-up relating to each solar battery array, in a system interconnection inverter connecting in parallel a plurality of the solar battery arrays input. SOLUTION: In the power conversion apparatus for solar power generations with a plurality of solar battery modules 8a, 8b, 8c serving as the power source, boost chopper parts 26a, 26b, 26c for performing maximum power follow-up of each solar battery module 8a, 8b, 8c for every thereof and a DC/DC converter of waveform forming parts 34a, 34b, 34c, 34d, etc. are provided, maximum power is led through from each solar battery module 8a, 8b, 8c thereafter to be collectively converted into an AC output by an inverter 23, a DC/AC converter 36, etc. COPYRIGHT: (C)2004,JPO&NCIPI
Patent•
29 Jan 2004
TL;DR: In this article, a solar-powered pumping device consisting of a solar power converter for generating power from sunlight, a pump driven by power from a solar powered converter, and an actuator for controlling the orientation of the converter is presented.
Abstract: A solar-powered pumping device comprising: a solar power converter for generating power from sunlight; a pump driven by power from said solar power converter; an actuator for controlling the orientation of said solar power converter; and a controller for controlling said actuator to orient said solar power converter for optimum generation of power, said controller comprising a receiver for receiving broadcast time data, and an ephemerides calculator for calculating the position of the sun on the basis of the received time data.
Patent•
16 Jan 2004
TL;DR: The Coherent-Micro-Macro-Collector (CMMC) as discussed by the authors is a unique total solar collector system consisting of concentrator and receiver for solar power conversion and production.
Abstract: Due to an ever growing shortage of conventional energy sources, there is an increasingly intense interest in harnessing solar energy. Broadly this invention deals with the general concept of method, apparatus, and consequences of focussing light. Specifically the Coherent-Micro-Macro-Collector of this invention is the unique total solar collector system consisting of concentrator and receiver. Method and apparatus are detailed for systems with: 1. Passive or non-tracking. 2. Semi-Passive tracking 2. Single-axis tracking. 3. Two-axis tracking. Also detailed are means for operating the collector system of micro-optics and receiver on the ground and protection means. A particularly important object of the CMMC is the focussing of sunlight for solar power conversion and production.
20 Jun 2004
TL;DR: In this paper, a linear reoriented coordinates method (LRCM) was proposed to approximate the maximum power for a photovoltaic inverter system for solar distributed generation.
Abstract: This paper describes a novel method to approximate the maximum power for a photovoltaic inverter system for solar distributed generation It is designed for power systems applications and utilities The proposed method takes in consideration the interaction between solar panels, photovoltaic inverter, maximum power point tracking (MPPT) control, solar panel DC side dynamic model and the effective intensity of light over the solar panel The new method has the advantage to provide a new simple way to approximate the optimal voltage or rated voltage (V/sub op/), the optimal or rated current (l/sub op/) and maximum power rating (P/sub max/) produced by a solar panel and the photovoltaic inverter Furthermore, this straightforward method will be named linear reoriented coordinates method (LRCM) with the advantage that P/sub max/ and V/sub op/ can be approximated using the same variables as the dynamic model without using complicate approximations or Taylor series Finally, some simulations results are presented
27 Sep 2004
TL;DR: In this article, the development of a photovoltaic system for energy supply to the public illumination in peak demand of an electric energy distribution system is discussed. But the authors focus on the use of the electronic ballast with the batteries.
Abstract: This work deals with the development of a photovoltaic system for energy supply to the public illumination in peak demand of an electric energy distribution system. The PV system stores during the day and supplies during the evening electric energy to a 70 W high-pressure sodium lamp (HPS) for two and a half hours, considering an average solar radiation of 5500 W/m/sup 2//day. During the day, the solar energy is captured by a photovoltaic panel and stored in lead acid batteries through a boost converter. This converter makes possible the battery to be charged at the photovoltaic maximum power point (MPP). In the evening the HPS lamp is started up through an electronic ballast, which operates with zero volt switch (ZVS). The control system, based on a AT90SSS35 RISC microcontroller, seeks the photovoltaic maximum power point, monitors the batteries charge and determines the time operation of the DC/DC converter, that makes possible the use of the electronic ballast with the batteries.