- Email: [email protected]
00865 Profile of impurities in polycrystalline silicon samples purified in an electron beam melting furnace
07 Alternative energy sources (solar energy) derived Tom the traditional syngas, and further converts able chemical fuel.
04/00882 generation Odeh,
Performance systems
S D. et al. Energy
fossil-fuel-based production of zinc and solar energy into storable and transport-
evaluation Conversion
of solar thermal
and Management,
2003,
electric 44, (15),
2425-2443.
A unified model of a solar electric generation system (SEGS) is developed using a thermo-hydrodynamic model of a direct steam collector combined with a model of a traditional steam power house. The model is used to study the performance of different collector field and power house arrangements under Australian conditions. To find the effect of collector inclination on the SEGS overall performance, the SEGS performance is studied with a horizontal and an inclined DSG collector field by considering phase distribution and pressure drop in the collector field piping network. The appropriate spacing of collector arrays in the field is calculated by considering the shading between collectors. The annual performance of the SEGS is evaluated using the hourly radiation data for different sites in Australia.
04lOO883 Photoelectrochemical plated tin sulfide thin films Subramanian, (I),
characteristics
B. et al. Solar Energy
Materials
and Solar
of brush Cells, 2003,
79,
57-65.
Thin films of tin sulfide find wide applications in optoelectronic devices and window materials for heterojunction solar cells. Thin films of pSnS were brush plated onto tin oxide coated glass substrates from aqueous solution containing SnC12 and Na&03. Deposits have been characterized with XRD and SEM for structural analysis. Hot probe method showed invariably p-type nature for all the brush plated SnS films. The variation of space charge capacitance, C,,, with applied potential, V, was recorded for the PEC cell with p-SnS/Fe3+, Fe2+/Pt system. The spectral response of the PEC cell formed with SnS photoelectrode was studied and reported.
04/00884 Photovoltaic-powered remote Australian communities
desalination
system for
Richards, B. S. and Schlfer, A. I. Renewable Energy, 2003, 28, (l3), 2013-2022. This paper reports on the design and successful field testing of a photovoltaic (PV)-powered desalination system. The system described here is intended for use in remote areas of the Australian outback, where fresh water is extremely limited and it is often necessary to drink high salinity bore water. A hybrid membrane configuration is implemented, whereby an ultrafiltration (UF) module is used for removing particulates, bacteria and viruses, while a reverse osmosis (RO) or nanofiltration (NF) membrane retains the salts. The concepts of water and energy recovery are implemented in the design. Field trials, performed in White Cliffs (New South Wales), demonstrated that clean drinking water was able to be produced from a variety of feed waters, including high salinity (3500 mgil) bore water and high turbidity (200 NTU) dam water. The specific energy consumption ranged from 2 to 8 kW h/m3 of disinfected and desalinated drinking water, depending on the salinity of the feed water and the system operating conditions. The optimum operating pressure when filtering bore water was determined to be in the range 6-7 bar.
04/00885 Profile of impurities in polycrystallins silicon samples purified in an electron beam melting furnace Pires, J. C. S. et al. Solar (3), 347-355.
Energy
Materials
and Solar
Cells,
2003,
19,
The photovoltaic properties of the polycrystalline silicon depend mainly on the crystalline structure (grain size and presence of defects) and of the purity of the material. The production of monocrystalline silicon for high-efficiency solar cells requires an extremely complex and expensive process. Therefore, the production of photovoltaic energy for terrestrial use, on a large scale, demands an alternative and lowcost method, especially in terms of purification of the starting material. The use of metallurgical grade silicon and the purifying of the same, through melting in electron beam furnace under a 10m3 Pa vacuum, is a method, which is able to provide high-purity material (99.999% Si). In this research, the results of the chemical analysis of polycrystalline silicon purified in an electron beam melting furnace, specially in terms of distribution of impurity due to their position in the sample related to the direction of solidification, are presented.
04/00888
Small hybrid solar power system
Kane, M. et al. Energy, 2003, 28, (14), 1427-1443. This paper introduces a novel concept of mini-hybrid solar power plant integrating a field of solar concentrators, two superposed organic Rankine cycles (ORC) and a (bio-)diesel engine. The ORC include hermetic scroll expander-generators (The word expander is often used to characterize units recovering the expansion energy of a gas, in particular when based on a volumetric machine. The word turbine or
112
Fuel and Energy Abstracts
March 2004
expander will be used indifferently in this paper) and the sun tracking solar collectors are composed of rows of flat mirror bands (CEP) arranged in a plane, that focus the solar energy onto a collector tube similar to those used in SEGS plants in California. Waste heat from both the exhaust gases and the block cooling of the thermal engine are also heat sources for the ORCs. Such units meet electricity, cooling and pumping needs of remote settlements. The thermal engine guarantees a minimum level of both power and heat availability at night or during cloudy periods. Laboratory tests, made with the superposed ORCs only, confirmed adequate operational characteristics with good performances over a broad range of conditions. A few preliminary tests on the site of the solar power plant when coupled with the engine confirmed a reasonable behaviour and the interest of the concept even at part load or during sharp variations of the thermal supply.
04/00887 Solar hydrogen production by thermal decomposition of natural gas using a vortex-flow
reactor
Hirsch,
D. and Steinfeld, A. Internutional Journal of Hydrogen Energy, 2004, 29, (l), 47-55. The endothermic decomposition of natural gas is experimentally investigated using concentrated solar radiation as the source of hightemperature process heat. The solar chemical reactor features a vortex flow of CHI confined to a cavity-receiver and laden with carbon particles that serve simultaneously as radiant absorbers and nucleation sites for the heterogeneous decomposition reaction. A 5 kW reactor prototype was fabricated and tested in a high-flux solar furnace with power flux intensities exceeding 3500 kW/m2. The chemical reactor engineering, experimental setup, and test results are described. Maximum chemical conversion of CH4 to Hz and C(gr) was 67% at 1600 K and 1 bar. Carbon formed was of nano-filamentary nature. The proposed solar hybrid chemical process conserves natural gas, reduces CO2 emissions, and provides a transition path to solar hydrogen.
04/00888
Solar performance
of hemispherical
vault roofs
G6mez-Mufioz, V. M. et al. Building and Environment, 2003, 38, (12), 1431-1438. In hot climates, the improvement of comfort by passive solar techniques is a very important issue. In many parts of the world such as the Middle East, vault roofs are widely used in construction. The solar and energy performance of a hemispherical vault roof is studied, including the auto-shading instant effect during several days for different latitudes and throughout the year also. The results are compared with the standard horizontal flat roofing used in the typical modern low-cost housing in Mexico. The hemispherical vault receives around 35% less energy than the flat roof between the equinoxes, besides having other advantages such as a greater ceiling height, natural ventilation and illumination possibilities, and structural stability.
04/00889 networks Reddy, 2003.
Solar resource and comoarison
K. S. and 44. (15).
Ranjan,
estimation using artificial neural with other correlation models M. Energy
Conversion
and
Management,
2519-2530.
Artificial neural network (ANN)-based models for estimation of monthly mean daily and hourly values of solar global radiation are presented in this paper. Solar radiation data from 13 stations spread over India around the year have been used for training and testing the ANN. The solar radiation data from 11 locations (six from South India and five from North India) were used for training the neural networks and data from the remaining two locations (one each from South India and North India) were used for testing the estimated values. The results of the ANN model have been compared with other empirical regression models. The solar radiation estimations by ANN are in good agreement with the actual values and are superior to those of other available models. The maximum mean absolute relative deviation of predicted hourly global radiation tested is 4.07%. The results indicate that the ANN model shows promise for evaluating solar global radiation possibilities at the places where monitoring stations are not established.
04iOO870 Solar selective absorbers based on twodimensional W surface gratings with submicron periods high-temperature photothermal conversion Hitoshi,
S. et al. Solar
Energy
Materials
and Solar
Cells,
2003,
for
79, (I),
35-49.
Spectral properties and thermal stability of two-dimensional (2D) W surface gratings with submicron periodicity are investigated to develop solar selective absorbers for high-temperature applications. Numerical calculations based on the rigorous coupled-wave analysis technique have been performed for simulating the spectral properties of W gratings. The results indicate that the gratings with microcavities have a good spectral selectivity suited for high-temperature applications, while the gratings with micropyramids realize a high solar absorptance over 0.92. 2D surface gratings with submicron holes have been fabricated on W substrates by the fast atom beam etching with highly ordered porous
04/00882 generation Odeh,
Performance systems
S D. et al. Energy
fossil-fuel-based production of zinc and solar energy into storable and transport-
evaluation Conversion
of solar thermal
and Management,
2003,
electric 44, (15),
2425-2443.
A unified model of a solar electric generation system (SEGS) is developed using a thermo-hydrodynamic model of a direct steam collector combined with a model of a traditional steam power house. The model is used to study the performance of different collector field and power house arrangements under Australian conditions. To find the effect of collector inclination on the SEGS overall performance, the SEGS performance is studied with a horizontal and an inclined DSG collector field by considering phase distribution and pressure drop in the collector field piping network. The appropriate spacing of collector arrays in the field is calculated by considering the shading between collectors. The annual performance of the SEGS is evaluated using the hourly radiation data for different sites in Australia.
04lOO883 Photoelectrochemical plated tin sulfide thin films Subramanian, (I),
characteristics
B. et al. Solar Energy
Materials
and Solar
of brush Cells, 2003,
79,
57-65.
Thin films of tin sulfide find wide applications in optoelectronic devices and window materials for heterojunction solar cells. Thin films of pSnS were brush plated onto tin oxide coated glass substrates from aqueous solution containing SnC12 and Na&03. Deposits have been characterized with XRD and SEM for structural analysis. Hot probe method showed invariably p-type nature for all the brush plated SnS films. The variation of space charge capacitance, C,,, with applied potential, V, was recorded for the PEC cell with p-SnS/Fe3+, Fe2+/Pt system. The spectral response of the PEC cell formed with SnS photoelectrode was studied and reported.
04/00884 Photovoltaic-powered remote Australian communities
desalination
system for
Richards, B. S. and Schlfer, A. I. Renewable Energy, 2003, 28, (l3), 2013-2022. This paper reports on the design and successful field testing of a photovoltaic (PV)-powered desalination system. The system described here is intended for use in remote areas of the Australian outback, where fresh water is extremely limited and it is often necessary to drink high salinity bore water. A hybrid membrane configuration is implemented, whereby an ultrafiltration (UF) module is used for removing particulates, bacteria and viruses, while a reverse osmosis (RO) or nanofiltration (NF) membrane retains the salts. The concepts of water and energy recovery are implemented in the design. Field trials, performed in White Cliffs (New South Wales), demonstrated that clean drinking water was able to be produced from a variety of feed waters, including high salinity (3500 mgil) bore water and high turbidity (200 NTU) dam water. The specific energy consumption ranged from 2 to 8 kW h/m3 of disinfected and desalinated drinking water, depending on the salinity of the feed water and the system operating conditions. The optimum operating pressure when filtering bore water was determined to be in the range 6-7 bar.
04/00885 Profile of impurities in polycrystallins silicon samples purified in an electron beam melting furnace Pires, J. C. S. et al. Solar (3), 347-355.
Energy
Materials
and Solar
Cells,
2003,
19,
The photovoltaic properties of the polycrystalline silicon depend mainly on the crystalline structure (grain size and presence of defects) and of the purity of the material. The production of monocrystalline silicon for high-efficiency solar cells requires an extremely complex and expensive process. Therefore, the production of photovoltaic energy for terrestrial use, on a large scale, demands an alternative and lowcost method, especially in terms of purification of the starting material. The use of metallurgical grade silicon and the purifying of the same, through melting in electron beam furnace under a 10m3 Pa vacuum, is a method, which is able to provide high-purity material (99.999% Si). In this research, the results of the chemical analysis of polycrystalline silicon purified in an electron beam melting furnace, specially in terms of distribution of impurity due to their position in the sample related to the direction of solidification, are presented.
04/00888
Small hybrid solar power system
Kane, M. et al. Energy, 2003, 28, (14), 1427-1443. This paper introduces a novel concept of mini-hybrid solar power plant integrating a field of solar concentrators, two superposed organic Rankine cycles (ORC) and a (bio-)diesel engine. The ORC include hermetic scroll expander-generators (The word expander is often used to characterize units recovering the expansion energy of a gas, in particular when based on a volumetric machine. The word turbine or
112
Fuel and Energy Abstracts
March 2004
expander will be used indifferently in this paper) and the sun tracking solar collectors are composed of rows of flat mirror bands (CEP) arranged in a plane, that focus the solar energy onto a collector tube similar to those used in SEGS plants in California. Waste heat from both the exhaust gases and the block cooling of the thermal engine are also heat sources for the ORCs. Such units meet electricity, cooling and pumping needs of remote settlements. The thermal engine guarantees a minimum level of both power and heat availability at night or during cloudy periods. Laboratory tests, made with the superposed ORCs only, confirmed adequate operational characteristics with good performances over a broad range of conditions. A few preliminary tests on the site of the solar power plant when coupled with the engine confirmed a reasonable behaviour and the interest of the concept even at part load or during sharp variations of the thermal supply.
04/00887 Solar hydrogen production by thermal decomposition of natural gas using a vortex-flow
reactor
Hirsch,
D. and Steinfeld, A. Internutional Journal of Hydrogen Energy, 2004, 29, (l), 47-55. The endothermic decomposition of natural gas is experimentally investigated using concentrated solar radiation as the source of hightemperature process heat. The solar chemical reactor features a vortex flow of CHI confined to a cavity-receiver and laden with carbon particles that serve simultaneously as radiant absorbers and nucleation sites for the heterogeneous decomposition reaction. A 5 kW reactor prototype was fabricated and tested in a high-flux solar furnace with power flux intensities exceeding 3500 kW/m2. The chemical reactor engineering, experimental setup, and test results are described. Maximum chemical conversion of CH4 to Hz and C(gr) was 67% at 1600 K and 1 bar. Carbon formed was of nano-filamentary nature. The proposed solar hybrid chemical process conserves natural gas, reduces CO2 emissions, and provides a transition path to solar hydrogen.
04/00888
Solar performance
of hemispherical
vault roofs
G6mez-Mufioz, V. M. et al. Building and Environment, 2003, 38, (12), 1431-1438. In hot climates, the improvement of comfort by passive solar techniques is a very important issue. In many parts of the world such as the Middle East, vault roofs are widely used in construction. The solar and energy performance of a hemispherical vault roof is studied, including the auto-shading instant effect during several days for different latitudes and throughout the year also. The results are compared with the standard horizontal flat roofing used in the typical modern low-cost housing in Mexico. The hemispherical vault receives around 35% less energy than the flat roof between the equinoxes, besides having other advantages such as a greater ceiling height, natural ventilation and illumination possibilities, and structural stability.
04/00889 networks Reddy, 2003.
Solar resource and comoarison
K. S. and 44. (15).
Ranjan,
estimation using artificial neural with other correlation models M. Energy
Conversion
and
Management,
2519-2530.
Artificial neural network (ANN)-based models for estimation of monthly mean daily and hourly values of solar global radiation are presented in this paper. Solar radiation data from 13 stations spread over India around the year have been used for training and testing the ANN. The solar radiation data from 11 locations (six from South India and five from North India) were used for training the neural networks and data from the remaining two locations (one each from South India and North India) were used for testing the estimated values. The results of the ANN model have been compared with other empirical regression models. The solar radiation estimations by ANN are in good agreement with the actual values and are superior to those of other available models. The maximum mean absolute relative deviation of predicted hourly global radiation tested is 4.07%. The results indicate that the ANN model shows promise for evaluating solar global radiation possibilities at the places where monitoring stations are not established.
04iOO870 Solar selective absorbers based on twodimensional W surface gratings with submicron periods high-temperature photothermal conversion Hitoshi,
S. et al. Solar
Energy
Materials
and Solar
Cells,
2003,
for
79, (I),
35-49.
Spectral properties and thermal stability of two-dimensional (2D) W surface gratings with submicron periodicity are investigated to develop solar selective absorbers for high-temperature applications. Numerical calculations based on the rigorous coupled-wave analysis technique have been performed for simulating the spectral properties of W gratings. The results indicate that the gratings with microcavities have a good spectral selectivity suited for high-temperature applications, while the gratings with micropyramids realize a high solar absorptance over 0.92. 2D surface gratings with submicron holes have been fabricated on W substrates by the fast atom beam etching with highly ordered porous