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cooling combined-cycle
14 Fuel science and technology (fuel cell technology) simulation was carried out based on computational systems. The mathematical model developed was built taking into account common features in present wet test gas meter as their internal configuration. Therefore, this work can be understood as a general analysis and its conclusions can be extended to whichever meter of this type. A software package was developed to facilitate the analysis of the variables involved in this physical process; besides the drum sizing was modelling using a CAD software. As a result of this investigation, theoretical basis were established for the analysing and designing of a M G C H meter, as a previous phase to the construction and evaluation of the prototype. Uncertainty analysis of each variable implicates in this model was beyond the scope of this study.
problems at higher stress ranges beyond shakedown involving changing residual stress fields. These include the evaluation of the plastic strain amplitude, ratchet limit and accumulated creep strains during high temperature dwell periods. The results are compared with calculation methods typical of the R5 methodologies. As in the accompanying paper, a 3D holed plate subjected to cyclic thermal load and constant mechanical load is assessed in detail as a typical example. The results demonstrate the flexibility of the linear matching method compared with current typical applications of high temperature assessment procedures.
06•02393 Study on prevention of ice adhesion to cooling wall due to voltage impression in ice storage - discussion on possibility of attraction of oil to wall
Zfieng, D. et al. Applied Energy~ 2006, 83, (4), 311-323. An absorption power/cooling combined cycle is proposed, and a thermodynamic analysis of the cycle is performed using log p T, log p h and T s diagrams. Based upon two performance criteria, the overall thermal-efficiency and exergy efficiency, the cycle has been analysed by means of a simulation. The overall thermal efficiency of the cycle is 24.2%, and the exergy efficiency is 37.3%.
Matsumoto, K. and Sakurai, H. International Journal of Refrigeration, 2006, 29, (1), 142-149. For ice storage, one of authors has studied new ice slurry formed by cooling a water-oil mixture with stirring. When the mixture is stirred in a vessel, oil is charged by static electricity due to friction. If the vessel wall can attract charged oil, prevention of ice adhesion to the wall may be realized. Therefore, in this paper, in order to observe behaviour of charged water-oil droplet or mixture in electric field by a high speed camera or video camera, two types of experiments were carried out. One was that the water-oil droplet charged by static electricity was made to fall plumb down between two electrodes with electric field or without electric field, varying the water content of droplet. The other was that a constant voltage was applied on the vessel filled with the water-oil mixture stirred. From experiments, it was confirmed that attracting force between the charged wall (electrode) and charged oil acted.
06•02394 The exergy fields in transport processes: their calculation and use Lior, N. et al. Energy, 2006, 31, (5), 553-578. This paper is a brief review of the method for analysing the space and time dependent exergy and irreversibility fields in processes. It presents the basic equations, the method for their use, major literature sources, and three examples from the authors' work: flow desiccation, combustion of oil droplets, and combustion of pulverized coal. Conclusions from this Second Law analysis are used to attempt process improvement suggestions.
06/02395 The linear matching method applied to the high temperature life integrity of structures. Part 1. Assessments involving constant residual stress fields Chert, H. F. et al. International Journal of Pressure Vessels and Piping, 2006, 83, (23, 123-135. Design and life assessment procedures for high temperatures are based on 'expert knowledge' in structural mechanics and materials science, combined with simplified methods of structural analysis. Of these, R5 is one of the most widely used life assessment methods internationally with procedures based on reference stress techniques and shakedown calculations using linear elastic solutions. These have been augmented by full finite element analysis and, recently, the development of a new programming method, the linear matching method (LMM), that allows a range of direct solutions that include shakedown methods and simplified analysis in excess of shakedown. In this paper, LMM procedures are compared with calculations typical of those employed in R5 for cyclic loading problems when the assumption of a constant residual stress field is appropriate including shakedown and limit analyses, creep rupture analysis and the evaluation of accumulated creep deformation. A typical example of a 3D holed plate subjected to a cyclic thermal load and a constant mechanical load is assessed in detail. These comparisons demonstrate the significant advantages of linear matching methods for a typical case. For a range of cyclic problems when the residual stress field varies during the cycle, which include the evaluation of plastic strain amplitude, ratchet limit and accumulated creep strains during a high temperature dwell periods, the corresponding LMM and R5 procedures are discussed in an accompanying paper.
06/02396 The linear matching method applied to the high temperature life integrity of structures. Part 2, Assessments beyond shakedown involving changing residual stress fields Chen, H. F. et al. Ittternational Journal of Pressure Vessels attd Piping, 2006, 83, (2), 136 147. In an accompanying paper, the application of the linear matching method to the high temperature life assessment of structures was discussed and compared with assessment procedures, typical of those used in RS, for a range of cyclic problems within shakedown. These included shakedown and limit analyses, creep rupture analysis and the evaluation of rapid cycle creep deformation. In this paper, procedures based on the linear matching method are presented for a range of cyclic
06/02397 Thermodynamic analysis of a novel absorption power/cooling combined-cycle
06/02398 Thermodynamic analysis of absorption systems using artificial neural network Sencan, A. et al. Renewable Energy, 2006, 31, (1), 29-43. Thermodynamic analysis of absorption systems is a very complex process, mainly because of the limited experimental data and analytical functions required for calculating the thermodynamic properties of fluid pairs, which usually involves the solution of complex differential equations, In order to simplify this complex process, Artificial neural networks (ANNs) are used. In this study, ANNs are used as a new approach for the determination of the thermodynamic properties of LiBr-water and LiCl-water solutions which have been the most widely used in the absorption heat pump systems. Instead of complex differential equations and limited experimental data, faster and simpler solutions were obtained by using equations derived from the ANN model. It was found that the coefficient of multiple determination (R 2value) between the actual and A N N predicted data is equal to about 0.999 for the enthalpy of both LiBr-water and LiC1 water solutions. As seen from the results obtained, the calculated thermodynamic properties are obviously within acceptable limits. In addition, the coefficient of performance (COP) of absorption systems operating under different conditions with LiB~water and LiCl-water solutions is calculated. The use of the derived equations, which can be employed with any programming language or spreadsheet program for the estimation of the enthalpy of the solutions, as described in this paper, may make the use of dedicated A N N software unnecessary.
Fuel cell technology 06/02399 A hybrid model of cathode of PEM fuel cell using the interdigitated gas distributor Liu, X.-L. et al. International Journol of IIydrogen Energy, 2006, 31, (33, 379 389. A two-dimensional (2D), single- and two-phase, hybrid multi-component transport model is developed for the cathode of PEM fuel cell using interdigitated gas distributor. The continuity equation and Darcy's law are used to describe the flow of the reactant gas and production water. The production water is treated as vapour when the current density is small, and as two-phase while the current density is greater than the critical current density. The advection-diffusion equations are utilized to study species transport of multi-component mixture gas. The Butler-Volmer equation is prescribed for the domain in the catalyst layer. The predicted results of the hybrid model agree well with the available experimental data. The model is used to investigate the effects of operating conditions and the cathode structure parameters on the performance of the PEM fuel cell. It is observed that liquid water appears originally in the cathodic catalyst layer over outlet channel under intermediate current and tends to be distributed uniformly by the capillary force with the increase of the current. It is found that reduction of the width of outlet channel can enhance the performance of PEM fuel cell via the increase of the current density over this region, which has, seemingly, not been discussed in previous literatures.
06/02400 Characterization of electrode structures and the related performance of direct methanol fuel cells Chert, C. Y. and Tsao, C. S. International Journal of Hydrogen Energy, 2006, 31, (3), 391-398. The performance of membrane electrode assemblies (MEAs) in fuel cells is substantially affected by the structures of the electrodes. An increase of about 25% in power performance was achieved merely by
Fuel and Energy Abstracts September 2006
363
problems at higher stress ranges beyond shakedown involving changing residual stress fields. These include the evaluation of the plastic strain amplitude, ratchet limit and accumulated creep strains during high temperature dwell periods. The results are compared with calculation methods typical of the R5 methodologies. As in the accompanying paper, a 3D holed plate subjected to cyclic thermal load and constant mechanical load is assessed in detail as a typical example. The results demonstrate the flexibility of the linear matching method compared with current typical applications of high temperature assessment procedures.
06•02393 Study on prevention of ice adhesion to cooling wall due to voltage impression in ice storage - discussion on possibility of attraction of oil to wall
Zfieng, D. et al. Applied Energy~ 2006, 83, (4), 311-323. An absorption power/cooling combined cycle is proposed, and a thermodynamic analysis of the cycle is performed using log p T, log p h and T s diagrams. Based upon two performance criteria, the overall thermal-efficiency and exergy efficiency, the cycle has been analysed by means of a simulation. The overall thermal efficiency of the cycle is 24.2%, and the exergy efficiency is 37.3%.
Matsumoto, K. and Sakurai, H. International Journal of Refrigeration, 2006, 29, (1), 142-149. For ice storage, one of authors has studied new ice slurry formed by cooling a water-oil mixture with stirring. When the mixture is stirred in a vessel, oil is charged by static electricity due to friction. If the vessel wall can attract charged oil, prevention of ice adhesion to the wall may be realized. Therefore, in this paper, in order to observe behaviour of charged water-oil droplet or mixture in electric field by a high speed camera or video camera, two types of experiments were carried out. One was that the water-oil droplet charged by static electricity was made to fall plumb down between two electrodes with electric field or without electric field, varying the water content of droplet. The other was that a constant voltage was applied on the vessel filled with the water-oil mixture stirred. From experiments, it was confirmed that attracting force between the charged wall (electrode) and charged oil acted.
06•02394 The exergy fields in transport processes: their calculation and use Lior, N. et al. Energy, 2006, 31, (5), 553-578. This paper is a brief review of the method for analysing the space and time dependent exergy and irreversibility fields in processes. It presents the basic equations, the method for their use, major literature sources, and three examples from the authors' work: flow desiccation, combustion of oil droplets, and combustion of pulverized coal. Conclusions from this Second Law analysis are used to attempt process improvement suggestions.
06/02395 The linear matching method applied to the high temperature life integrity of structures. Part 1. Assessments involving constant residual stress fields Chert, H. F. et al. International Journal of Pressure Vessels and Piping, 2006, 83, (23, 123-135. Design and life assessment procedures for high temperatures are based on 'expert knowledge' in structural mechanics and materials science, combined with simplified methods of structural analysis. Of these, R5 is one of the most widely used life assessment methods internationally with procedures based on reference stress techniques and shakedown calculations using linear elastic solutions. These have been augmented by full finite element analysis and, recently, the development of a new programming method, the linear matching method (LMM), that allows a range of direct solutions that include shakedown methods and simplified analysis in excess of shakedown. In this paper, LMM procedures are compared with calculations typical of those employed in R5 for cyclic loading problems when the assumption of a constant residual stress field is appropriate including shakedown and limit analyses, creep rupture analysis and the evaluation of accumulated creep deformation. A typical example of a 3D holed plate subjected to a cyclic thermal load and a constant mechanical load is assessed in detail. These comparisons demonstrate the significant advantages of linear matching methods for a typical case. For a range of cyclic problems when the residual stress field varies during the cycle, which include the evaluation of plastic strain amplitude, ratchet limit and accumulated creep strains during a high temperature dwell periods, the corresponding LMM and R5 procedures are discussed in an accompanying paper.
06/02396 The linear matching method applied to the high temperature life integrity of structures. Part 2, Assessments beyond shakedown involving changing residual stress fields Chen, H. F. et al. Ittternational Journal of Pressure Vessels attd Piping, 2006, 83, (2), 136 147. In an accompanying paper, the application of the linear matching method to the high temperature life assessment of structures was discussed and compared with assessment procedures, typical of those used in RS, for a range of cyclic problems within shakedown. These included shakedown and limit analyses, creep rupture analysis and the evaluation of rapid cycle creep deformation. In this paper, procedures based on the linear matching method are presented for a range of cyclic
06/02397 Thermodynamic analysis of a novel absorption power/cooling combined-cycle
06/02398 Thermodynamic analysis of absorption systems using artificial neural network Sencan, A. et al. Renewable Energy, 2006, 31, (1), 29-43. Thermodynamic analysis of absorption systems is a very complex process, mainly because of the limited experimental data and analytical functions required for calculating the thermodynamic properties of fluid pairs, which usually involves the solution of complex differential equations, In order to simplify this complex process, Artificial neural networks (ANNs) are used. In this study, ANNs are used as a new approach for the determination of the thermodynamic properties of LiBr-water and LiCl-water solutions which have been the most widely used in the absorption heat pump systems. Instead of complex differential equations and limited experimental data, faster and simpler solutions were obtained by using equations derived from the ANN model. It was found that the coefficient of multiple determination (R 2value) between the actual and A N N predicted data is equal to about 0.999 for the enthalpy of both LiBr-water and LiC1 water solutions. As seen from the results obtained, the calculated thermodynamic properties are obviously within acceptable limits. In addition, the coefficient of performance (COP) of absorption systems operating under different conditions with LiB~water and LiCl-water solutions is calculated. The use of the derived equations, which can be employed with any programming language or spreadsheet program for the estimation of the enthalpy of the solutions, as described in this paper, may make the use of dedicated A N N software unnecessary.
Fuel cell technology 06/02399 A hybrid model of cathode of PEM fuel cell using the interdigitated gas distributor Liu, X.-L. et al. International Journol of IIydrogen Energy, 2006, 31, (33, 379 389. A two-dimensional (2D), single- and two-phase, hybrid multi-component transport model is developed for the cathode of PEM fuel cell using interdigitated gas distributor. The continuity equation and Darcy's law are used to describe the flow of the reactant gas and production water. The production water is treated as vapour when the current density is small, and as two-phase while the current density is greater than the critical current density. The advection-diffusion equations are utilized to study species transport of multi-component mixture gas. The Butler-Volmer equation is prescribed for the domain in the catalyst layer. The predicted results of the hybrid model agree well with the available experimental data. The model is used to investigate the effects of operating conditions and the cathode structure parameters on the performance of the PEM fuel cell. It is observed that liquid water appears originally in the cathodic catalyst layer over outlet channel under intermediate current and tends to be distributed uniformly by the capillary force with the increase of the current. It is found that reduction of the width of outlet channel can enhance the performance of PEM fuel cell via the increase of the current density over this region, which has, seemingly, not been discussed in previous literatures.
06/02400 Characterization of electrode structures and the related performance of direct methanol fuel cells Chert, C. Y. and Tsao, C. S. International Journal of Hydrogen Energy, 2006, 31, (3), 391-398. The performance of membrane electrode assemblies (MEAs) in fuel cells is substantially affected by the structures of the electrodes. An increase of about 25% in power performance was achieved merely by
Fuel and Energy Abstracts September 2006
363