Showing papers on "Solar energy published in 2004"
TL;DR: A survey of the various types of solar thermal collectors and applications is presented in this paper, where an analysis of the environmental problems related to the use of conventional sources of energy is presented and the benefits offered by renewable energy systems are outlined.
2,620 citations
TL;DR: The new indoline dye was optimized for the amount of 4-tert-butyl pyridine in the electrolyte and cholic acid as a coadsorbent and the solar energy to current conversion efficiencies reached 8.00%, which was the highest obtained efficiency for dye-sensitized solar cells based on metal-free organic dyes without an antireflection layer.
Abstract: We now report metal-free organic dyes having a new type of indoline structure, which exhibits high efficiencies in dye-sensitized solar cells. The solar energy to current conversion efficiencies with the new indoline dye was 6.51%. Under the same conditions, the N3 dye was 7.89% and the N719 dye was 8.26%. The new indoline dye was optimized for the amount of 4-tert-butyl pyridine in the electrolyte and cholic acid as a coadsorbent. Subsequently, the solar energy to current conversion efficiencies reached 8.00%. This value was the highest obtained efficiency for dye-sensitized solar cells based on metal-free organic dyes without an antireflection layer.
1,162 citations
TL;DR: In this article, a composite time series of total solar irradiance spaceborne measurements is used to predict the sun's irradiance within 0.1% on average, as accurately as current measurements.
843 citations
TL;DR: In this article, the basic principles of photocatalysis, focusing in particular on important mechanistic and kinetic aspects as well as on some requirements for efficient photocatalysts, are discussed.
791 citations
TL;DR: In this article, two hybrid planar-mixed molecular heterojunction cells in series were used to achieve a power conversion efficiency of 5.7±0.3% under 1 sun simulated AM1.5G solar illumination.
Abstract: We demonstrate high-efficiency organic photovoltaic cells by stacking two hybrid planar-mixed molecular heterojunction cells in series. Absorption of incident light is maximized by locating the subcell tuned to absorb long-wavelength light nearest to the transparent anode, and tuning the second subcell closest to the reflecting metal cathode to preferentially absorb short-wavelength solar energy. Using the donor, copper phthalocyanine, and the acceptor, C60, we achieve a maximum power conversion efficiency of ηP=(5.7±0.3)% under 1 sun simulated AM1.5G solar illumination. An open-circuit voltage of VOC⩽1.2V is obtained, doubling that of a single cell. Analytical models suggest that power conversion efficiencies exceeding 6.5% can be obtained by this architecture.
604 citations
TL;DR: A review of the various solar hybrid beam splitting systems proposed in the literature and the different spectrum splitting strategies employed is presented in this article, where the authors present a review of different spectrum-splitting strategies employed.
395 citations
TL;DR: In this paper, a review of the process for the development of superstrate and substrate solar cells is presented, where the authors discuss the effect of various deposition methods on the electronic properties of the absorber layers and the efficiency of solar cells.
Abstract: Cu(In,Ga)Se2 and CdTe heterojunction solar cells grown on rigid (glass) or flexible foil substrates require p-type absorber layers of optimum optoelectronic properties and n-type wide-bandgap partner layers to form the p–n junction. Transparent conducting oxide and specific metal layers are used for front and back electrical contacts. Efficiencies of solar cells depend on various deposition methods as they control the optoelectronic properties of the layers and interfaces. Certain treatments, such as addition of Na in Cu(In,Ga)Se2 and CdCl2 treatment of CdTe have a direct influence on the electronic properties of the absorber layers and efficiency of solar cells. Processes for the development of superstrate and substrate solar cells are reviewed. Copyright © 2004 John Wiley & Sons, Ltd.
379 citations
TL;DR: In this article, the authors presented a method to quantify the potential of facades and roofs located in urban areas for active and passive solar heating, photovoltaic electricity production and daylighting.
357 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, a mathematical model was used to estimate the total solar radiation on the tilted PV surface, and to determine optimum tilt angles for a PV panel installed in Sanliurfa, Turkey.
319 citations
Book•
15 Dec 2004
TL;DR: In this paper, the various types of photovoltaic cells are described and their characteristics reviewed, and a comprehensive account of current activity in this important field of research and industry is provided.
Abstract: The capture and use of solar energy has been growing for many years, but only in recent times have advances in design and manufacture allowed us to see the incorporation of solar energy as a significant player in the renewable energy arena. Solar cells are at the heart of any photovoltaic system and in this book the various types are described and their characteristics reviewed. Going beyond materials, design and function, ?Solar Cells? also covers their testing, monitoring and calibration thus providing a comprehensive account of current activity in this important field of research and industry. 'Solar Cells' has been abstracted from the recent 'Practical Handbook of Photovoltaics' by the same editors
TL;DR: Using coordinated observations from instruments on the Advanced Composition Explorer (ACE), the Solar and Heliospheric Observatory (SOHO), and the Ramaty High Energy Solar Spectroscopic Imager (RHESSI), this article evaluated the energetics of two well-observed flare/CME events on 21 April 2002 and 23 July 2002.
Abstract: Using coordinated observations from instruments on the Advanced Composition Explorer (ACE), the Solar and Heliospheric Observatory (SOHO), and the Ramaty High Energy Solar Spectroscopic Imager (RHESSI), we have evaluated the energetics of two well-observed flare/CME events on 21 April 2002 and 23 July 2002. For each event, we have estimated the energy contents (and the likely uncertainties) of (1) the coronal mass ejection, (2) the thermal plasma at the Sun, (3) the hard X-ray producing accelerated electrons, (4) the gamma-ray producing ions, and (5) the solar energetic particles. The results are assimilated and discussed relative to the probable amount of nonpotential magnetic energy available in a large active region.
TL;DR: In this article, a new type of solar irradiance scheme is developed based on radiative transfer models (RTM) using atmospheric parameter information retrieved from the Meteosat Second Generation (MSG) satellite (clouds, ozone, water vapour) and the ERS-2/ENVISAT satellites (aerosols, ozone).
TL;DR: In this article, the authors presented an energy and exergy analysis of a GSHP system with a 50 m vertical 1.25 in. nominal diameter U-bend ground heat exchanger.
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.
TL;DR: In this paper, the authors investigated the productivity of asymmetric greenhouse type still (ASGHT) having mirrors on its inside walls and found that the distilled water output of the asymmetrical greenhouse type was 20% higher than that of symmetric greenhouse types.
TL;DR: In the house building sector, central solar heating plants presently offer the most cost-favourable application of all possibilities of solar-thermal systems as discussed by the authors, and more than 50% of the annual heating demand for space heating and domestic hot water can be supplied by solar energy.
TL;DR: In this paper, a regenerative solar desalination unit is modeled and its performance evaluated, and the results of the simulations show that the productivity of the regenerative still is 20% higher compared to the conventional still.
TL;DR: In this paper, phase change materials (PCMs) were used as an internal room lining for a multi-zone, highly glazed and naturally ventilated passive solar building to store solar energy.
TL;DR: In this article, a light-driven self-charging capacitor was fabricated as an efficient solar energy storage device, which achieved in situ storage of visible light energy as an electrical power at high quantum conversion efficiency.
Abstract: A light-driven self-charging capacitor was fabricated as an efficient solar energy storage device. The device, which we name the photocapacitor, achieves in situ storage of visible light energy as an electrical power at high quantum conversion efficiency. The photocapacitor was constructed on a multilayered photoelectrode comprising dye-sensitized semiconductor nanoparticles/hole-trapping layer/activated carbon particles in contact with an organic electrolyte solution, in which photogenerated charges are stored at the electric double layer. Repeated charge-discharge cycles with a charging voltage of >0.45V yielded a capacitance of 0.69Fcm−2.
TL;DR: In this paper, the authors put forward the solar energy potential in Turkey using artificial neural networks (ANNs) and investigated the best approach for each station by using different learning algorithms and a logistic sigmoid transfer function in the neural network with developed software.
TL;DR: In this paper, the authors discuss recent developments in the calibration of broadband solar radiometric instrumentation and improving broadband solar radiation measurement accuracy, including an improved diffuse sky reference and radiometer calibration and characterization software for outdoor pyranometer calibrations.
TL;DR: In this paper, the performance of passive and active solar stills for different Indian climatic conditions was evaluated for hourly variations of average insolation at the Chennai, Jodhpur, Kolkata, Mumbai and New Delhi stations.
TL;DR: In this paper, the authors describe some of the new and emerging developments, with special emphasis on: (1) nanoscale antennas for direct conversion of sunlight to electricity with potential conversion efficiencies approaching 80-90%; (2) new thermodynamic cycles for solar thermal power, that have the potential to reduce capital costs by 50%; and (3) solar photocatalytic oxidation for cleanup of industrial wastewater, drinking water, soil and air.
TL;DR: In this paper, the authors investigated the environmental protection offered by the two most widely used renewable energy systems, i.e., solar water heating and solar space heating, and showed that by using solar energy, considerable amounts of greenhouse polluting gasses are avoided.
TL;DR: In this paper, the development of CdTe/CdS solar cells on flexible substrates is reviewed in both terrestrial and space applications and the specific power of the solar cells is an important factor in space applications.
Patent•
14 Sep 2004
TL;DR: In this article, a solar energy utilization unit (SUE) comprises a solar radiation concentrating optics (SRCO) and a SRCO receiver, including a first receiver component designed to convert into electric energy radiation in a first part of the solar spectrum, and a second receiver components designed to transform into electric information radiation in the second part of solar spectrum which is different from the first part.
Abstract: A solar energy utilization unit comprises a solar radiation concentrating optics and a solar radiation receiver including a first receiver component designed to convert into electric energy radiation in a first part of the solar spectrum, and a second receiver components designed to convert into electric energy radiation in a second part of the solar spectrum which is different from said first part. The solar radiation concentrating optics comprises a concave primary reflector adapted to reflect incident solar radiation towards the secondary reflector, and a convex secondary reflector adapted to reflect radiation in the first part of the solar spectrum into the first receiver component and also to transmit radiation in the second part of the solar spectrum into the second receiver component. The primary reflector is formed with a centrally disposed opening, via which the first receiver component is adapted to receive the radiation reflected by the secondary receiver. The primary receiver may have central and peripheral components, wherein the central component is made of a material which withstands heat better than the material from which the peripheral component is made.
TL;DR: In this paper, a comprehensive technical review of solar desalination with a multi-effect cycle providing a better understanding of the process is presented, and discussion on methods to improve system performance and efficiency paves the way towards possible commercialisation of such units in the future.
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.