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05157 Simulation of the transient behavior of a closed-cycle salt-gradient solar pond
07 Alternative energy sources (solar energy)
96105146 Modifications of the heliostat procedure for irradiante estimates from satellite images Beyer, H. G. et al., Solar Energy, Mar. 1996, 56, (3), 207-212. Images taken by geostationary satellites may be used to estimate solar irradiance fluxes at the earth’s surface. The Helisat method is a widely applied procedure for this task. It is based on the empirical correlation between a satellite derived cloud index and the irradiance at the ground. Modifications to this procedure that may reduce the temporal variability of the correlation are presented. The modified method may open the way to the use of a generic relation of cloud index and global irradiance.
96105147 On the estimation of atmospheric radiation from surface meteorological data Skartveit. A. et al., Solar Enemy, Apr. 1996, 56. (4). 349-359. A large number of.simple form&e fir the estimation of total longwave atmospheric irradiance have been compared to both measured data and to output from the spectral model MODTRAN. MODTRAN predictions under cloudless sky agree well with the average of 38 profile-based models, and observed irradiances on the average agree with MODTRAN predictions within some 5 Wm.‘.
96105146 Performance evaluation of a new hybrid solar heatIng and ventilation system optimlsed for U.K. weather conditions Bldg. Environ., Mar. 1996, 31, (2), Imbabi, M. S. and Musset, A. 145.157 _ _ ___.
Discusses the results from a detailed parametric study to evaluate the performance of a newly proposed hybrid solar housing development in Monymusk, Scotland.
96105149 Performance evaluation of an active solar distillation system Kumar, S. and Tiwari, G. N. Ejtergy, Sep. 19Y6! 21, (9), 805-808. The authors have studied an active solar distillation system during peak summer days. The system is made of fibre-reinforced plastic and is coupled to a flat-plate collection. Performance of single and double-effect solar distillation, with and without water-flow over the glass cover, was monitored. It was found that an active solar still with water flow over the glass cover gives the maximum yield.
96105150 Performance of a solar still: Predicted effect of enhanced evaporation area on yield and evaporation temperature Kwatra, H. S. Solar Energy, Mar. 1996, 56, (3), 261-266. A solar still with enlarged evawration area was simulated on the commuter in order to explore thcquantiiative relationship between evaporation’area and the distillation yield. The results showed a gain of 19.6% in the yield when the evaporation area was quadrupled: and an asymptotic (infinite area) gain of around 30.2%. A thermodynamic analysis of the two separate energy conversion processes occurring within the still led to ‘availability’ based definitions of efficiencies for the collector and the evaporator-condenser. The analysis showed that all the asvmptotic improvement in yield is attributable to the more efficient evaporation-condensation process in the still with enlarged evaporation area.
96105151 A perspective on thermal energy storage systems for solar energy applications Inl. J. Energy Research, Jun. 1996, 20, (6), Dincer, I. and Dost, S. 547-557. The use of thermal energy storage (TES) systems is essential for solar power systems because of fluctuations in the solar energy input. Several classes of storage may be required for a single installation, depending on the type and scale of the solar power plant itself, and the nature of its inteeration with conventional utilitvi svstems. For heatine and hot water i appKcations,, water and phase change materials constitute the principle storage mecha. Soil, rock and other solids are used as well. Water has the advantage of approximately 80% less volume than that of water for a temperature variation of lO”C, which is the difference between temperatures of a fully charged and a fully discharged storage tank.
96105152 Power output of AI/SnO,/n-SI solar cell Singh, K. and Tamakloe, R. Y. Solar Energy, Apr. 1996, 56, (4), 343-348. An Al/SnOdn-Si solar cell from n-type silicon wafers using chemical vapour deposition has been fabricated. The fabrication details, I-V characteristics determining conversion-efficiency (N,,,), open circuit voltage (V,) and short circuit current (I,,) has been presented.
96105153 The Real Goods solar living center Solar Today, May-Jun. 1996, 10, (3), 20-23. Describes the Real Goods’ new solar living center in Hopland, California which is a shining example of an ecologically sound, aesthetically pleasing, economically feasible commercial development.
362
Fuel and Energy
Abstracts
September
1996
96105154 A review of analytic solutions for a model p-n junction cell under low-injection conditions Archer, M. D. er al., Solar Energy Marerials & Solar Cells, Apr. 1996, 40, (2), 133-176. Analvtic treatments of a one-dimensional model o-n homoiunction or hete;junction cell exhibiting superposition are consdlidated, e&ded and illustrated. The model cell consists of two quasi-neutral regions of finite width and a junction region which is treated-as two back-to-back exhaustion layers. Analytic solutions are obtained for the carrier concentration and flux profiles (current densities), quasi-Fermi levels and carrier collection probabilities and efficiencies, in the dark and under illumination, as a function of distance across the cell. For the most part, it is assumed that the light intensity falls exponentially with depth, the authors briefly examined also the case of isotropically forward-scattering light.
The role of lifestyles, loads and budgets In PV sys96105155 tems design McCray, M. Solar Today, May-Jun. 1996, 10, (3), 31-32. The author discusses photovoltaic systems which he has been selling for over 12 years.
96105156 Simple string construction method for tailored concentrators in maximum-flux solar energy edge-ray collectors Gordon, J. M. Solar Energy, Mar. 1996, 56, (3), 279-284. The authors show how tailored edge-ray concentrators in two-stage solar collectors that can closely approach the thermodynamic limit to concentration can be constructed with a simple method of strings. The procedure is illustrated for parabolic and Fresnel primary reflectors. The string-construction method is based on the edee-rav orinciole of nonimaeine ootics. is a generalization of Fermat’s prinriple; and hah been develo”&dY fdr thk genertion of earlier ideal nonimaging concentrators. The string method can supplant the more time-consuming procedure of numerical solution of the reflector governing differential equation.
96105157 Simulation of the transient behavior of a closedcycle salt-gradient solar pond Alagao, F. B. Solar Dterg); Mar. 1996, 56, (3), 245-260. A one-dimensional simulation model for a closed-cycle salt-gradient solar pond (CCSGSP) is developed. It simulates the transient behaviour of CCSGSP using finite difference method. Validation of some parts of the model is presented using data from the RMIT solar pond. Close correlations between computed and measured data was obtained. Three modes of salt recycling are also presented.
96105158 Sizing procedure for photovoltaic refrigerating systems using a simple approach of the LLP calculation Awanto, C. er al., Solar Energy, Apr. 1996, 56, (4), 337-342. The authors present a sizing procedure for photovoltaic refrigerating systems. Bv simulating the system oueration. loss of load orobabilitv (LLP) calculation is performed and allows one to.optimise the iizes of thk photo: voltaic generator and the refrigerated enclosure. The system components are characterized Py energy models which are joined in the simulation procedure to describe the system behaviour. This procedure has been validated and shows a good agreement with experimental results.
Solar energy: Today’s technologies for a sustaina96105159 ble future American Solar Energy Sociery, 2400 Central Ave., Suite G-I, Boulder, CO.80301, USA, $20.00, 1996, 50 pp. The book is a one-stop source for information on the latest developments in solar energy technologies. From generating electricity to heating and cooling homes, solar energy is the environmentally friendly power option. Edited for an informed! but non-technical, audience concerned about the environmental, econornlc, health, national security implications of current energy consumption habits.
The solar hardening of steels: Experiments and 96105160 predictions Yang, Y. et al., Solar Energy Materials & Solar Cells, Apr. 1996, 40, (2), 103-121. A method of hardening steels with a solar furnace has been developed. Initial trials were conducted with a plain carbon steel to measure the thermal transients which could be expected, and from the results a simple thermal model was developed to predict what would be needed to achieve hardening. The consequent improvements in the process allowed the surface of low-alloy steel to be hardened. To predict more exactly the reaction of steels to solar irradiation, a thermochemical model was developed. It uses a finite difference method to calculate the thermal transient induced by the solar beam, and a calculation of its kinetic strength to predict how much austenite will form. A comparison of the cooling curve with the ‘ITT diagram of the steels then allows the percentage of martensite and hardness to be predicted.
96105146 Modifications of the heliostat procedure for irradiante estimates from satellite images Beyer, H. G. et al., Solar Energy, Mar. 1996, 56, (3), 207-212. Images taken by geostationary satellites may be used to estimate solar irradiance fluxes at the earth’s surface. The Helisat method is a widely applied procedure for this task. It is based on the empirical correlation between a satellite derived cloud index and the irradiance at the ground. Modifications to this procedure that may reduce the temporal variability of the correlation are presented. The modified method may open the way to the use of a generic relation of cloud index and global irradiance.
96105147 On the estimation of atmospheric radiation from surface meteorological data Skartveit. A. et al., Solar Enemy, Apr. 1996, 56. (4). 349-359. A large number of.simple form&e fir the estimation of total longwave atmospheric irradiance have been compared to both measured data and to output from the spectral model MODTRAN. MODTRAN predictions under cloudless sky agree well with the average of 38 profile-based models, and observed irradiances on the average agree with MODTRAN predictions within some 5 Wm.‘.
96105146 Performance evaluation of a new hybrid solar heatIng and ventilation system optimlsed for U.K. weather conditions Bldg. Environ., Mar. 1996, 31, (2), Imbabi, M. S. and Musset, A. 145.157 _ _ ___.
Discusses the results from a detailed parametric study to evaluate the performance of a newly proposed hybrid solar housing development in Monymusk, Scotland.
96105149 Performance evaluation of an active solar distillation system Kumar, S. and Tiwari, G. N. Ejtergy, Sep. 19Y6! 21, (9), 805-808. The authors have studied an active solar distillation system during peak summer days. The system is made of fibre-reinforced plastic and is coupled to a flat-plate collection. Performance of single and double-effect solar distillation, with and without water-flow over the glass cover, was monitored. It was found that an active solar still with water flow over the glass cover gives the maximum yield.
96105150 Performance of a solar still: Predicted effect of enhanced evaporation area on yield and evaporation temperature Kwatra, H. S. Solar Energy, Mar. 1996, 56, (3), 261-266. A solar still with enlarged evawration area was simulated on the commuter in order to explore thcquantiiative relationship between evaporation’area and the distillation yield. The results showed a gain of 19.6% in the yield when the evaporation area was quadrupled: and an asymptotic (infinite area) gain of around 30.2%. A thermodynamic analysis of the two separate energy conversion processes occurring within the still led to ‘availability’ based definitions of efficiencies for the collector and the evaporator-condenser. The analysis showed that all the asvmptotic improvement in yield is attributable to the more efficient evaporation-condensation process in the still with enlarged evaporation area.
96105151 A perspective on thermal energy storage systems for solar energy applications Inl. J. Energy Research, Jun. 1996, 20, (6), Dincer, I. and Dost, S. 547-557. The use of thermal energy storage (TES) systems is essential for solar power systems because of fluctuations in the solar energy input. Several classes of storage may be required for a single installation, depending on the type and scale of the solar power plant itself, and the nature of its inteeration with conventional utilitvi svstems. For heatine and hot water i appKcations,, water and phase change materials constitute the principle storage mecha. Soil, rock and other solids are used as well. Water has the advantage of approximately 80% less volume than that of water for a temperature variation of lO”C, which is the difference between temperatures of a fully charged and a fully discharged storage tank.
96105152 Power output of AI/SnO,/n-SI solar cell Singh, K. and Tamakloe, R. Y. Solar Energy, Apr. 1996, 56, (4), 343-348. An Al/SnOdn-Si solar cell from n-type silicon wafers using chemical vapour deposition has been fabricated. The fabrication details, I-V characteristics determining conversion-efficiency (N,,,), open circuit voltage (V,) and short circuit current (I,,) has been presented.
96105153 The Real Goods solar living center Solar Today, May-Jun. 1996, 10, (3), 20-23. Describes the Real Goods’ new solar living center in Hopland, California which is a shining example of an ecologically sound, aesthetically pleasing, economically feasible commercial development.
362
Fuel and Energy
Abstracts
September
1996
96105154 A review of analytic solutions for a model p-n junction cell under low-injection conditions Archer, M. D. er al., Solar Energy Marerials & Solar Cells, Apr. 1996, 40, (2), 133-176. Analvtic treatments of a one-dimensional model o-n homoiunction or hete;junction cell exhibiting superposition are consdlidated, e&ded and illustrated. The model cell consists of two quasi-neutral regions of finite width and a junction region which is treated-as two back-to-back exhaustion layers. Analytic solutions are obtained for the carrier concentration and flux profiles (current densities), quasi-Fermi levels and carrier collection probabilities and efficiencies, in the dark and under illumination, as a function of distance across the cell. For the most part, it is assumed that the light intensity falls exponentially with depth, the authors briefly examined also the case of isotropically forward-scattering light.
The role of lifestyles, loads and budgets In PV sys96105155 tems design McCray, M. Solar Today, May-Jun. 1996, 10, (3), 31-32. The author discusses photovoltaic systems which he has been selling for over 12 years.
96105156 Simple string construction method for tailored concentrators in maximum-flux solar energy edge-ray collectors Gordon, J. M. Solar Energy, Mar. 1996, 56, (3), 279-284. The authors show how tailored edge-ray concentrators in two-stage solar collectors that can closely approach the thermodynamic limit to concentration can be constructed with a simple method of strings. The procedure is illustrated for parabolic and Fresnel primary reflectors. The string-construction method is based on the edee-rav orinciole of nonimaeine ootics. is a generalization of Fermat’s prinriple; and hah been develo”&dY fdr thk genertion of earlier ideal nonimaging concentrators. The string method can supplant the more time-consuming procedure of numerical solution of the reflector governing differential equation.
96105157 Simulation of the transient behavior of a closedcycle salt-gradient solar pond Alagao, F. B. Solar Dterg); Mar. 1996, 56, (3), 245-260. A one-dimensional simulation model for a closed-cycle salt-gradient solar pond (CCSGSP) is developed. It simulates the transient behaviour of CCSGSP using finite difference method. Validation of some parts of the model is presented using data from the RMIT solar pond. Close correlations between computed and measured data was obtained. Three modes of salt recycling are also presented.
96105158 Sizing procedure for photovoltaic refrigerating systems using a simple approach of the LLP calculation Awanto, C. er al., Solar Energy, Apr. 1996, 56, (4), 337-342. The authors present a sizing procedure for photovoltaic refrigerating systems. Bv simulating the system oueration. loss of load orobabilitv (LLP) calculation is performed and allows one to.optimise the iizes of thk photo: voltaic generator and the refrigerated enclosure. The system components are characterized Py energy models which are joined in the simulation procedure to describe the system behaviour. This procedure has been validated and shows a good agreement with experimental results.
Solar energy: Today’s technologies for a sustaina96105159 ble future American Solar Energy Sociery, 2400 Central Ave., Suite G-I, Boulder, CO.80301, USA, $20.00, 1996, 50 pp. The book is a one-stop source for information on the latest developments in solar energy technologies. From generating electricity to heating and cooling homes, solar energy is the environmentally friendly power option. Edited for an informed! but non-technical, audience concerned about the environmental, econornlc, health, national security implications of current energy consumption habits.
The solar hardening of steels: Experiments and 96105160 predictions Yang, Y. et al., Solar Energy Materials & Solar Cells, Apr. 1996, 40, (2), 103-121. A method of hardening steels with a solar furnace has been developed. Initial trials were conducted with a plain carbon steel to measure the thermal transients which could be expected, and from the results a simple thermal model was developed to predict what would be needed to achieve hardening. The consequent improvements in the process allowed the surface of low-alloy steel to be hardened. To predict more exactly the reaction of steels to solar irradiation, a thermochemical model was developed. It uses a finite difference method to calculate the thermal transient induced by the solar beam, and a calculation of its kinetic strength to predict how much austenite will form. A comparison of the cooling curve with the ‘ITT diagram of the steels then allows the percentage of martensite and hardness to be predicted.