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02039 Modeling and experimental study on an innovative passive cooling system-NVP system
16 Fuel science and technology (fundamental science, analysis, instrumentation) has been implemented and, through its predictions, an efficient control strategy has been developed in a system that resulted in significant energy savings and environmental benefits.
03/02034 Device simulation and modeling microcrystalline silicon solar ceils
of
Takakura, H. and Hamakawa, Y. Solar Energy Materials and Solar Cells, 2002, 74, (l-4), 479-487. Device modelling for p-i-n junction basis thin film microcrystalline Si solar cells has been examined with a simple model of columnar grain structure utilizing two-dimensional device simulator. The simulation results of solar cell characteristics show that open-circuit voltage (V,,,) and fill factor considerably depend on structural parameters such as grain size and acceptor doping in intrinsic layer, while short-circuit current density (J,,) is comparatively stable by built-in electric field in the i-layer. It is also found that conversion efficiency of more than 16% could be expected with 1 pm grain size and well-passivated condition with 10 pm thick i-layer and optical confinement.
03/02035 Extreme radiation hardness and light-weighted thin-film indium phosphide solar ceil and its computer simulation Li, G. et al. Solar Energy Materials and Solar Cells, 2003, 75, (l-2). 307-3 12. A very light-weighted and extreme radiation hardness high-doping nfi-p’ InP solar cell is developed. The total thickness of its epitaxial layer is only 0.22 Km. It is more radiation hardened than many other structures so that it can provide the required output power for spacecraft even after a decade at 3200 km polar orbits. Its end of life efficiency is about 10% (AMO, 1Sun); its highest power/weight ratio is about 130 W/g (only the weight of epitaxial layers is considered). The surprising fact is that all of these are obtained from a very simple structure.
03/02036 Kinetic of butadiene
modeling
of counterflow
diffusion
flames
Granata, S. et al. Combustion and Flame, 2002, 131, (3), 273-284. A comprehensive, semi-detailed kinetic scheme was used to simulate the chemical structures of counterflow diffusion and fuel-rich premixed 1,3-butadiene flames, to better understand the formation of polycyclic aromatic hydrocarbons (PAH). The results showed that model predictions were in good agreement with the experiments for most of the species in both the flames. In the counterflow flames highermolecular weight products are slightly over predicted. The pathways characterizing the pollutant formation are very different in the premixed and in the counterflow flames confirming or suggesting the need to verify and refine the detailed mechanisms tuned for premixed conditions when they are extrapolated and used in diffusion flames. Reaction paths analysis for PAH formation in the counterflow flame shows that both the HACA mechanism and the resonantly stabilized radicals are important for the growth of PAH. The kinetic model was unsuccessful in predicting the increased reactivity in 02-doped diffusion flames, indicating the need for improved models and also the opportunity of new experiments of butadiene oxidation in the intermediate temperature region.
03/02037 Kinetic and hydrocarbons temperatures
modeling of the interactions between NO in the oxidation of hydrocarbons at low
Faravelli, T. et al. Combustion and Flame, 2003, 132, (l-2), 188-207. A general and detailed chemical kinetic model has been developed and tested to investigate the interaction between NO and hydrocarbons during the oxidation of a hydrocarbon at low temperatures. The model describes the influence of NO and was validated through comparison with several different experimental data sets for various temperatures, stoichiometries and hydrocarbon fuels. The good agreement observed across the whole investigation range confirms the validity of the kinetic assumptions and the reliability of the model. The effect of NO on the oxidation of hydrocarbons and the influence of hydrocarbons on the conversion of NO to NO2 are discussed. The kinetic scheme also refers to higher temperatures, as typical of reburning, but to reduce the breadth of the work the paper is focused on low temperature interactions. Nevertheless, the paper presents the complete set of reactions in the nitrogen submechanism.
03/02036 Kinetics modeiiing of Fischer-Tropsch over an industrial Fe-Cu-K catalyst
the olefin re-adsorption mechanism is then proposed. In this model, different sites are assumed for FTS reactions and water gas shift (WGS) reaction, respectively. Rate expressions for FTS reactions are based on the carbide polymerization mechanism, in which olefin readsorption is considered to be a reverse step of olefin desorption reaction. Rate expression for WGS reaction is based on the formate mechanism. An integral reactor model considering both FI’S and WGS kinetics is used to describe the reaction system, and the simultaneous estimation of kinetic parameters is conducted with non-linear regression procedure. The optimal model shows that the rate determining steps in FTS reactions proceed via the desorption of hydrocarbon products and the adsorption of CO and the slowest step in WGS reaction is the desorption of gaseous carbon dioxide via formate intermediate species. The activation energies of FTS reactions and WGS reaction are in good agreement with literature values.
03/02039 innovative
Modeling and experimental study on an passive cooling system-NVP system
Kang, Y. et al. Energy and Buildings, 2003, 35, (4), 417-425. A kind of innovative building energy efficiency system-Night Ventilation with PCM Packed Bed Storage (NVP) system is proposed. The mathematical model of NVP system is built to analyse its thermal behavior. The building thermal inertia, the model of Latent Heat Thermal Energy Storage (LHTES) system and the ventilation scheme are all taken into considered in the mathematical model. An experimental installation of NVP system used in Beijing is introduced. Its thermal performances including the effect on decreasing the room temperature and the energy consumption are discussed. Experimental results show that NVP system has great potential in the field of energy efficiency building. And the mathematical model of NVP system is validated with the experimental data.
03/02040 collector
Modeling and optimal design of ground air for heating in controlled environment greenhouse
Jain, D. and Tiwari, G. N. Energy Conversion and Management, 2003, 44, (8), 1357-1372. A mathematical model is devised to study the thermal behavior of a greenhouse while heating with a ground air collector (GAC). A computer program based on MatLab software has been used to predict the plant and room temperatures as a function of various design parameters of the ground air collector. Extensive experiments have been conducted during December 2000 to March 2001 for an even span greenhouse of effective floor area of 24 m* with a GAC and having a brick north wall. The model was validated experimentally in the climate of Delhi for the winter season. A parametric study involves the area of the GAC, mass flow rate and heat capacity. The predicted plant and room temperatures show fair agreement with the experimental values.
03/02041 Modeling combustion
of HMX/GAP pseudo-propellant
Kim, E. S. et al. Combustion and Flame, 2002, 131, (3), 227-245. A comprehensive numerical analysis of HMX/GAP pseudo-propellant combustion has been established to predict the propellant burning rate and detailed combustion wave structure over a broad range of ambient pressure, laser intensity, and propellant composition. The model takes into account various fundamental processes at scales sufficient to resolve the microscopic flame-zone physiochemistry. The thermochemical parameters of HMX and GAP are deduced from existing experimental data. Four global decomposition reactions of HMX and GAP in the condensed phase as well as subsequent reactions are included. In the gas phase, a detailed chemical kinetics scheme involving 74 species and 532 reactions is employed to describe the heat-release mechanism. The effect of the external CO2 laser on the propellant burning characteristics prevails at low pressures, but decreases at high pressures at which the conductive heat feedback from the gaseous flame to the condensed phase overrides surface absorption of radiation energy. The burning rate decreases with the addition of GAP at low pressures, even though GAP burns much faster than pure HMX. One factor contributing to this phenomenon is the rapid gasification of GAP displacing the primary flame away from the surface. Conversely, above a certain pressure level, the burning rate may be considerably enhanced by adding a small amount of GAP because of the higher surface temperature at which the exothermic decomposition of GAP plays a decisive role in providing energy to sustain propellant burning.
synthesis
Wang, Y-N. ef al. Fuel, 2003, 82, (2), 195-213. The kinetic experiments of Fischer-Tropsch synthesis (FTS) over an industrial Fe-Cu-K catalyst are carried out in a micro-fixed-bed reactor under the conditions as follows: temperature of 493-542 K, pressure of 10.9-30.9 bar, Hz/CO feed ratio of 0.98-2.99, and space velocity of 4000-10000 hi’. The effects of secondary reactions of olefins are investigated by co-feeding C2H2 and C3H6. A detailed kinetics model taking into account the increasingly proven evidence of
03102042 Modeling the hydrogeochemistry of aquitards using minimally disturbed samples in radial diffusion ceils Van Stempvoort, D. R. and van de; Kamp, G. Applied Geochemistry, 2003, 18, (4), 551-565. The radial diffusion method is a new technique that, among other applications, allows laboratory study of the chemistry of groundwater in intact aquitard materials. The computer model PHREEQC was used to simulate the changes in hydrochemistry observed in radial diffusion cells. A relatively small number of assumptions were required. In Fuel
and
Energy
Abstracts
September
2003
337
03/02034 Device simulation and modeling microcrystalline silicon solar ceils
of
Takakura, H. and Hamakawa, Y. Solar Energy Materials and Solar Cells, 2002, 74, (l-4), 479-487. Device modelling for p-i-n junction basis thin film microcrystalline Si solar cells has been examined with a simple model of columnar grain structure utilizing two-dimensional device simulator. The simulation results of solar cell characteristics show that open-circuit voltage (V,,,) and fill factor considerably depend on structural parameters such as grain size and acceptor doping in intrinsic layer, while short-circuit current density (J,,) is comparatively stable by built-in electric field in the i-layer. It is also found that conversion efficiency of more than 16% could be expected with 1 pm grain size and well-passivated condition with 10 pm thick i-layer and optical confinement.
03/02035 Extreme radiation hardness and light-weighted thin-film indium phosphide solar ceil and its computer simulation Li, G. et al. Solar Energy Materials and Solar Cells, 2003, 75, (l-2). 307-3 12. A very light-weighted and extreme radiation hardness high-doping nfi-p’ InP solar cell is developed. The total thickness of its epitaxial layer is only 0.22 Km. It is more radiation hardened than many other structures so that it can provide the required output power for spacecraft even after a decade at 3200 km polar orbits. Its end of life efficiency is about 10% (AMO, 1Sun); its highest power/weight ratio is about 130 W/g (only the weight of epitaxial layers is considered). The surprising fact is that all of these are obtained from a very simple structure.
03/02036 Kinetic of butadiene
modeling
of counterflow
diffusion
flames
Granata, S. et al. Combustion and Flame, 2002, 131, (3), 273-284. A comprehensive, semi-detailed kinetic scheme was used to simulate the chemical structures of counterflow diffusion and fuel-rich premixed 1,3-butadiene flames, to better understand the formation of polycyclic aromatic hydrocarbons (PAH). The results showed that model predictions were in good agreement with the experiments for most of the species in both the flames. In the counterflow flames highermolecular weight products are slightly over predicted. The pathways characterizing the pollutant formation are very different in the premixed and in the counterflow flames confirming or suggesting the need to verify and refine the detailed mechanisms tuned for premixed conditions when they are extrapolated and used in diffusion flames. Reaction paths analysis for PAH formation in the counterflow flame shows that both the HACA mechanism and the resonantly stabilized radicals are important for the growth of PAH. The kinetic model was unsuccessful in predicting the increased reactivity in 02-doped diffusion flames, indicating the need for improved models and also the opportunity of new experiments of butadiene oxidation in the intermediate temperature region.
03/02037 Kinetic and hydrocarbons temperatures
modeling of the interactions between NO in the oxidation of hydrocarbons at low
Faravelli, T. et al. Combustion and Flame, 2003, 132, (l-2), 188-207. A general and detailed chemical kinetic model has been developed and tested to investigate the interaction between NO and hydrocarbons during the oxidation of a hydrocarbon at low temperatures. The model describes the influence of NO and was validated through comparison with several different experimental data sets for various temperatures, stoichiometries and hydrocarbon fuels. The good agreement observed across the whole investigation range confirms the validity of the kinetic assumptions and the reliability of the model. The effect of NO on the oxidation of hydrocarbons and the influence of hydrocarbons on the conversion of NO to NO2 are discussed. The kinetic scheme also refers to higher temperatures, as typical of reburning, but to reduce the breadth of the work the paper is focused on low temperature interactions. Nevertheless, the paper presents the complete set of reactions in the nitrogen submechanism.
03/02036 Kinetics modeiiing of Fischer-Tropsch over an industrial Fe-Cu-K catalyst
the olefin re-adsorption mechanism is then proposed. In this model, different sites are assumed for FTS reactions and water gas shift (WGS) reaction, respectively. Rate expressions for FTS reactions are based on the carbide polymerization mechanism, in which olefin readsorption is considered to be a reverse step of olefin desorption reaction. Rate expression for WGS reaction is based on the formate mechanism. An integral reactor model considering both FI’S and WGS kinetics is used to describe the reaction system, and the simultaneous estimation of kinetic parameters is conducted with non-linear regression procedure. The optimal model shows that the rate determining steps in FTS reactions proceed via the desorption of hydrocarbon products and the adsorption of CO and the slowest step in WGS reaction is the desorption of gaseous carbon dioxide via formate intermediate species. The activation energies of FTS reactions and WGS reaction are in good agreement with literature values.
03/02039 innovative
Modeling and experimental study on an passive cooling system-NVP system
Kang, Y. et al. Energy and Buildings, 2003, 35, (4), 417-425. A kind of innovative building energy efficiency system-Night Ventilation with PCM Packed Bed Storage (NVP) system is proposed. The mathematical model of NVP system is built to analyse its thermal behavior. The building thermal inertia, the model of Latent Heat Thermal Energy Storage (LHTES) system and the ventilation scheme are all taken into considered in the mathematical model. An experimental installation of NVP system used in Beijing is introduced. Its thermal performances including the effect on decreasing the room temperature and the energy consumption are discussed. Experimental results show that NVP system has great potential in the field of energy efficiency building. And the mathematical model of NVP system is validated with the experimental data.
03/02040 collector
Modeling and optimal design of ground air for heating in controlled environment greenhouse
Jain, D. and Tiwari, G. N. Energy Conversion and Management, 2003, 44, (8), 1357-1372. A mathematical model is devised to study the thermal behavior of a greenhouse while heating with a ground air collector (GAC). A computer program based on MatLab software has been used to predict the plant and room temperatures as a function of various design parameters of the ground air collector. Extensive experiments have been conducted during December 2000 to March 2001 for an even span greenhouse of effective floor area of 24 m* with a GAC and having a brick north wall. The model was validated experimentally in the climate of Delhi for the winter season. A parametric study involves the area of the GAC, mass flow rate and heat capacity. The predicted plant and room temperatures show fair agreement with the experimental values.
03/02041 Modeling combustion
of HMX/GAP pseudo-propellant
Kim, E. S. et al. Combustion and Flame, 2002, 131, (3), 227-245. A comprehensive numerical analysis of HMX/GAP pseudo-propellant combustion has been established to predict the propellant burning rate and detailed combustion wave structure over a broad range of ambient pressure, laser intensity, and propellant composition. The model takes into account various fundamental processes at scales sufficient to resolve the microscopic flame-zone physiochemistry. The thermochemical parameters of HMX and GAP are deduced from existing experimental data. Four global decomposition reactions of HMX and GAP in the condensed phase as well as subsequent reactions are included. In the gas phase, a detailed chemical kinetics scheme involving 74 species and 532 reactions is employed to describe the heat-release mechanism. The effect of the external CO2 laser on the propellant burning characteristics prevails at low pressures, but decreases at high pressures at which the conductive heat feedback from the gaseous flame to the condensed phase overrides surface absorption of radiation energy. The burning rate decreases with the addition of GAP at low pressures, even though GAP burns much faster than pure HMX. One factor contributing to this phenomenon is the rapid gasification of GAP displacing the primary flame away from the surface. Conversely, above a certain pressure level, the burning rate may be considerably enhanced by adding a small amount of GAP because of the higher surface temperature at which the exothermic decomposition of GAP plays a decisive role in providing energy to sustain propellant burning.
synthesis
Wang, Y-N. ef al. Fuel, 2003, 82, (2), 195-213. The kinetic experiments of Fischer-Tropsch synthesis (FTS) over an industrial Fe-Cu-K catalyst are carried out in a micro-fixed-bed reactor under the conditions as follows: temperature of 493-542 K, pressure of 10.9-30.9 bar, Hz/CO feed ratio of 0.98-2.99, and space velocity of 4000-10000 hi’. The effects of secondary reactions of olefins are investigated by co-feeding C2H2 and C3H6. A detailed kinetics model taking into account the increasingly proven evidence of
03102042 Modeling the hydrogeochemistry of aquitards using minimally disturbed samples in radial diffusion ceils Van Stempvoort, D. R. and van de; Kamp, G. Applied Geochemistry, 2003, 18, (4), 551-565. The radial diffusion method is a new technique that, among other applications, allows laboratory study of the chemistry of groundwater in intact aquitard materials. The computer model PHREEQC was used to simulate the changes in hydrochemistry observed in radial diffusion cells. A relatively small number of assumptions were required. In Fuel
and
Energy
Abstracts
September
2003
337