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00521 Modelling of material properties influence on back junction thin polycrystalline silicon solar cells
07
Alternative
energy sources (solar energy)
Encapsulation of PV modules using ethylene vinyl 97100515 acetate copolymer as a pottant: a critical review Czanderna, A. W. and Pern, F. J., Solar Energy Materials and Solar Cells, Sept. 1996,43, (2) 191-181. The primary purpose of this work is to review the literature about what is and is not known about using ethylene vinyl acetate (EVA) copolymer as the encapsulant (or pottant) material in photovoltaic (PV) modules. Secondary purposes include elucidating the complexity of the encapsulation problem, providing an overview about encapsulation of PV cells and modules, and a historical overview of the relevant research and development on EVA, summarizing performance losses reported for PV systems deployed since approximately 1981, and summarizing the general problems of polymer stability in a solar environment, A critical review of aspects of reported work for cases that believed to be important is also included.
Electrical/electronic effects of titanium and iron in EFG and FZ solar cell silicon: SPVlEBlC analysis Dlamini, M. D., Solar Eneru Materials and Solar Cells, Oct. 1996, 43, (4),
97100516 impurities
353-361. In this paper results on surface photovoltage (SPV) and electron beam induced conductivity (EBIC) studies of edge-defined film-fed growth (EFG) and floating zone (FZ) silicon solar cell materials (both p-type) are presented. 97100517
inversion
Energy band structure and sheet resistance layer for silicon solar cells
of MIS
Lihui, Ci. et al., Solar EnergV Material.7 and Solar Cells, Oct. 1996, 43, (4), 325-333. The energy band structure, minority carrier concentration, and charge distribution of metal-insulator-semiconductor inversion layer (MIS/IL) Si solar cells have been calculated using Fermi-Dirac statistics. The variation of the cell’s sheet resistance with the fixed positive charge and interface state density have been analysed. The theoretical results tally well with the experiment results.
97100518 lands
A greenhouse
for the subtropical
Australian
Amos, R. N. ef al., Solar Energy, Dec. 1996, 17, (4) 25-27. In response to a need for an economical way to heat greenhouses subtropical Australian highlands, solar energy has been employed.
Influence of deposition temperature 97/00519 chromic properties of sputtered WOJ thidfilms
high-
in the
on electro-
Wang, J. and Bell, J. M., Solar Energy Materials and Solar Cells, Oct. 1996, 43, (4) 377-391. This report investigates the influence of deposition temperature on the electrochromic properties of reactively sputtered WOa films. A set of WO> films produced in the temperature range of 47-400°C is electrochemically cycled with a constant current supply, which provides an easy control of the charge injected into the films. Optical absorption after coloration, and therefore the coloration of the films, significantly increases with increasing deposition temperature (up to 400°C) in the wavelength range of approximately 1000-2500 nm. Both optical absorption and coloration efficiency decrease at the highest temperatures studied (350-400°C) over most of the visible spectrum (approximately 500-800 nm). Optical modulation across the solar spectrum remains fairly constant for charge injection of IO mC/cm*, and the modulation is quite satisfactory for all films for electrochromic device applications. The films produced at higher substrate temperatures show smaller modulation of the visible spectrum, compared with films sputtered at lower substrate temperatures. This could be more suitable for some applications of the solar control systems. The resistance of the films during the electrochemical process is found to increase with increasing substrate temperature. This could be more suitable for some applications of the solar control systems. The resistance of the films during the electrochemical process is found to increase with increasing substrate temperature. This causes difficulty in charge injection, requiring significantly larger voltages in techniques such as a cyclic voltammetry for the films deposited at higher temperature. As a result the good electrochromic performance of the films deposited at higher temperature can be masked by experimental conditions.
97100520 Limiting efficiencies version in multigap systems
for photovoltaic
energy
con-
Mart’, A. and Aratijo, G. L., Solar Enesy Ma/erials atid Solur Cells, Sept. 1996, 43, (2). 203-222. Multigap systems are better matched to the sun’s spectrum than single gap systems and are, therefore, more efficient as photovoltaic converters. This paper reviews the different thermodynamic approaches used in the past for computing the limiting efficiency for the conversion of solar energy into work. Within this thermodynamic context, the limit ranges from 85.4% to YS.O% depending on the assumptions made. Detailed balance theory provides a more accurate model of the photovoltaic converter. It leads to a limit of 86.8% for a system with an infinite number of cells, as already pointed out by other authors. In this work, however, we use the concepts of angle and energy restriction to emphasize that this limit is independent of the light concentration. Systems with a ,finite number of cells are also studied and their limiting efficiency is found to be higher than previously reported.
40
Fuel and Energy Abstracts
January 1997
97100521 Modelling of material properties influence junction thin polycrystalline silicon solar cells
on back
Dugas, J., Solar Energy Marerials and Solar Cells, Sept. 1996. 43, (2) lY3202. The influence of polycrystalline silicon properties on the performances of thin back junction solar cells has been investigated by means of a threedimensional model taking into account grain size. grain boundary recombination, volumic recombination, and surface recombination. The drastic influence of front surface recombination has been confirmed. The grain size has been shown to be of minor importance provided the grain size is not too small and the grain boundaries are correctly passivated. An optimal base thickness has been determined which is all the smaller that the material is more imperfect.
97100522 Non-stoichiometry bronzes: MXWOB.,
in thin
film
dilute
tungsten
Green, M. and Pita, K., Solar Energy Materiak and Solar Celh, Oct. 1996, 43, (4), 393-411. Thin films of tungsten trioxide have been prepared in various ways which give rise to different optical behaviour. The white light optical absorption versus inserted lithium atom concentration is measured and followed as a function of time. The influence of post-deposition treatment in oxygen at 300°C is studied, and the results of these experiments support the key role of non-stoichiometry. Previous thin film structural studies are re-enforced here by a structural investigation of evaporated films using the atomic force microscope. These optical-insertion data are interpreted by means of a model which proposes that electron trapping occurs at crystalline shear plane boundaries (which account for the non-stoichiometry). The extent and rate of trapping is modelled, and the experimental results are consistent with the trapping rate being proportional to the lithium atom concentration in the films. The importance of minimizing non-stoichiometry in electrochromic devices and in specimens of material for use in physical measurements is made clear.
97100523 Australia
The operations
building
at the Perth Zoo, Western
Baverstock, G., Solar Energy, Dec. 1996, 17, (4) h-8. The Operations Buildings at the Perth Zoo in Western Australia were designed to have the lowest energy use possible and to comply with the Zoo’s mission statement. The Perth Zoo is committed to implementing programs that raise its profile in ecological, conservation and environmental areas. The aim therefore was not simply to produce a modestly improved energy efficicency regime compared with traditional air-conditioned structures, but to demonstrate, with contemporary technology and design, a significantly improved performance.
97100524 Preparation sten oxide film
and properties
of electrochromic
tung-
Wang, H. et al., Solar Energ) Materials and Solar Cells, Oct. 1996. 43, (4), 345-352. Tungsten oxide films have been formed by poly-complex. The dip-coating solution was prepared by adding hydrogen peroxide to a tungsten acid solution which was obtained from ion exchange. Amorphous and crystalline films can be obtained at different firing temperature. Optical and electrochemical measurements of these films have been carried out. The XRD, IR, TG-DTA analysis and SEM morphologies observation are also described. The results show that these coatings have good electrochromic properties.
97100525
Solar ‘96-Energy
For Life
Parker, B., Solar Energv, Dec. 1996, 17, (4), 9-I I. The paper reviews the topics discussed at the Australia Solar Energy Society’s annual meeting at Darwin
97100526 selection
Survey
of solar desalination
and New Zealand
systems
and system
Kalogirou, S., Energy, 1907, 22, (I), 69-81. The most common sea water desalination systems available today are described. These are divided into two broad categories, namely, direct and indirect collection systems. In the former, solar energy is absorbed and used in the same piece of equipment whereas in the latter, two separate subsystems are used, one for solar energy conversion and one for desalination. Various systems are analysed with respect to their primary energy consumption, sea water treatment requirement, cost, and suitability for solar energy utilization. Of the various types of processes that are analysed, the multiple-effect boiling system and, in particular, the multiple-effect stack type evaporator, is the most suitable for solar energy utilization since it can be used under varying energy supplies without upset. In addition, this system has a low specific energy requirement, low equipment cost and also requires the simplest sea water treatment,
97100527 Theoretical using solar energy
study
of multi-stage
flash
distillation
Farwati, M. A., Energy, 1997, 22, (I), 1-S. Solar energy was utilized as a clean renewable heat source for operation of a multistage flash distillation system in Benghazi to produce distilled water, This paper examines the results of the stiudy.
Alternative
energy sources (solar energy)
Encapsulation of PV modules using ethylene vinyl 97100515 acetate copolymer as a pottant: a critical review Czanderna, A. W. and Pern, F. J., Solar Energy Materials and Solar Cells, Sept. 1996,43, (2) 191-181. The primary purpose of this work is to review the literature about what is and is not known about using ethylene vinyl acetate (EVA) copolymer as the encapsulant (or pottant) material in photovoltaic (PV) modules. Secondary purposes include elucidating the complexity of the encapsulation problem, providing an overview about encapsulation of PV cells and modules, and a historical overview of the relevant research and development on EVA, summarizing performance losses reported for PV systems deployed since approximately 1981, and summarizing the general problems of polymer stability in a solar environment, A critical review of aspects of reported work for cases that believed to be important is also included.
Electrical/electronic effects of titanium and iron in EFG and FZ solar cell silicon: SPVlEBlC analysis Dlamini, M. D., Solar Eneru Materials and Solar Cells, Oct. 1996, 43, (4),
97100516 impurities
353-361. In this paper results on surface photovoltage (SPV) and electron beam induced conductivity (EBIC) studies of edge-defined film-fed growth (EFG) and floating zone (FZ) silicon solar cell materials (both p-type) are presented. 97100517
inversion
Energy band structure and sheet resistance layer for silicon solar cells
of MIS
Lihui, Ci. et al., Solar EnergV Material.7 and Solar Cells, Oct. 1996, 43, (4), 325-333. The energy band structure, minority carrier concentration, and charge distribution of metal-insulator-semiconductor inversion layer (MIS/IL) Si solar cells have been calculated using Fermi-Dirac statistics. The variation of the cell’s sheet resistance with the fixed positive charge and interface state density have been analysed. The theoretical results tally well with the experiment results.
97100518 lands
A greenhouse
for the subtropical
Australian
Amos, R. N. ef al., Solar Energy, Dec. 1996, 17, (4) 25-27. In response to a need for an economical way to heat greenhouses subtropical Australian highlands, solar energy has been employed.
Influence of deposition temperature 97/00519 chromic properties of sputtered WOJ thidfilms
high-
in the
on electro-
Wang, J. and Bell, J. M., Solar Energy Materials and Solar Cells, Oct. 1996, 43, (4) 377-391. This report investigates the influence of deposition temperature on the electrochromic properties of reactively sputtered WOa films. A set of WO> films produced in the temperature range of 47-400°C is electrochemically cycled with a constant current supply, which provides an easy control of the charge injected into the films. Optical absorption after coloration, and therefore the coloration of the films, significantly increases with increasing deposition temperature (up to 400°C) in the wavelength range of approximately 1000-2500 nm. Both optical absorption and coloration efficiency decrease at the highest temperatures studied (350-400°C) over most of the visible spectrum (approximately 500-800 nm). Optical modulation across the solar spectrum remains fairly constant for charge injection of IO mC/cm*, and the modulation is quite satisfactory for all films for electrochromic device applications. The films produced at higher substrate temperatures show smaller modulation of the visible spectrum, compared with films sputtered at lower substrate temperatures. This could be more suitable for some applications of the solar control systems. The resistance of the films during the electrochemical process is found to increase with increasing substrate temperature. This could be more suitable for some applications of the solar control systems. The resistance of the films during the electrochemical process is found to increase with increasing substrate temperature. This causes difficulty in charge injection, requiring significantly larger voltages in techniques such as a cyclic voltammetry for the films deposited at higher temperature. As a result the good electrochromic performance of the films deposited at higher temperature can be masked by experimental conditions.
97100520 Limiting efficiencies version in multigap systems
for photovoltaic
energy
con-
Mart’, A. and Aratijo, G. L., Solar Enesy Ma/erials atid Solur Cells, Sept. 1996, 43, (2). 203-222. Multigap systems are better matched to the sun’s spectrum than single gap systems and are, therefore, more efficient as photovoltaic converters. This paper reviews the different thermodynamic approaches used in the past for computing the limiting efficiency for the conversion of solar energy into work. Within this thermodynamic context, the limit ranges from 85.4% to YS.O% depending on the assumptions made. Detailed balance theory provides a more accurate model of the photovoltaic converter. It leads to a limit of 86.8% for a system with an infinite number of cells, as already pointed out by other authors. In this work, however, we use the concepts of angle and energy restriction to emphasize that this limit is independent of the light concentration. Systems with a ,finite number of cells are also studied and their limiting efficiency is found to be higher than previously reported.
40
Fuel and Energy Abstracts
January 1997
97100521 Modelling of material properties influence junction thin polycrystalline silicon solar cells
on back
Dugas, J., Solar Energy Marerials and Solar Cells, Sept. 1996. 43, (2) lY3202. The influence of polycrystalline silicon properties on the performances of thin back junction solar cells has been investigated by means of a threedimensional model taking into account grain size. grain boundary recombination, volumic recombination, and surface recombination. The drastic influence of front surface recombination has been confirmed. The grain size has been shown to be of minor importance provided the grain size is not too small and the grain boundaries are correctly passivated. An optimal base thickness has been determined which is all the smaller that the material is more imperfect.
97100522 Non-stoichiometry bronzes: MXWOB.,
in thin
film
dilute
tungsten
Green, M. and Pita, K., Solar Energy Materiak and Solar Celh, Oct. 1996, 43, (4), 393-411. Thin films of tungsten trioxide have been prepared in various ways which give rise to different optical behaviour. The white light optical absorption versus inserted lithium atom concentration is measured and followed as a function of time. The influence of post-deposition treatment in oxygen at 300°C is studied, and the results of these experiments support the key role of non-stoichiometry. Previous thin film structural studies are re-enforced here by a structural investigation of evaporated films using the atomic force microscope. These optical-insertion data are interpreted by means of a model which proposes that electron trapping occurs at crystalline shear plane boundaries (which account for the non-stoichiometry). The extent and rate of trapping is modelled, and the experimental results are consistent with the trapping rate being proportional to the lithium atom concentration in the films. The importance of minimizing non-stoichiometry in electrochromic devices and in specimens of material for use in physical measurements is made clear.
97100523 Australia
The operations
building
at the Perth Zoo, Western
Baverstock, G., Solar Energy, Dec. 1996, 17, (4) h-8. The Operations Buildings at the Perth Zoo in Western Australia were designed to have the lowest energy use possible and to comply with the Zoo’s mission statement. The Perth Zoo is committed to implementing programs that raise its profile in ecological, conservation and environmental areas. The aim therefore was not simply to produce a modestly improved energy efficicency regime compared with traditional air-conditioned structures, but to demonstrate, with contemporary technology and design, a significantly improved performance.
97100524 Preparation sten oxide film
and properties
of electrochromic
tung-
Wang, H. et al., Solar Energ) Materials and Solar Cells, Oct. 1996. 43, (4), 345-352. Tungsten oxide films have been formed by poly-complex. The dip-coating solution was prepared by adding hydrogen peroxide to a tungsten acid solution which was obtained from ion exchange. Amorphous and crystalline films can be obtained at different firing temperature. Optical and electrochemical measurements of these films have been carried out. The XRD, IR, TG-DTA analysis and SEM morphologies observation are also described. The results show that these coatings have good electrochromic properties.
97100525
Solar ‘96-Energy
For Life
Parker, B., Solar Energv, Dec. 1996, 17, (4), 9-I I. The paper reviews the topics discussed at the Australia Solar Energy Society’s annual meeting at Darwin
97100526 selection
Survey
of solar desalination
and New Zealand
systems
and system
Kalogirou, S., Energy, 1907, 22, (I), 69-81. The most common sea water desalination systems available today are described. These are divided into two broad categories, namely, direct and indirect collection systems. In the former, solar energy is absorbed and used in the same piece of equipment whereas in the latter, two separate subsystems are used, one for solar energy conversion and one for desalination. Various systems are analysed with respect to their primary energy consumption, sea water treatment requirement, cost, and suitability for solar energy utilization. Of the various types of processes that are analysed, the multiple-effect boiling system and, in particular, the multiple-effect stack type evaporator, is the most suitable for solar energy utilization since it can be used under varying energy supplies without upset. In addition, this system has a low specific energy requirement, low equipment cost and also requires the simplest sea water treatment,
97100527 Theoretical using solar energy
study
of multi-stage
flash
distillation
Farwati, M. A., Energy, 1997, 22, (I), 1-S. Solar energy was utilized as a clean renewable heat source for operation of a multistage flash distillation system in Benghazi to produce distilled water, This paper examines the results of the stiudy.