The Experts below are selected from a list of 3750 Experts worldwide ranked by ideXlab platform

Saad Mahmoud - One of the best experts on this subject based on the ideXlab platform.

  • performance enhancement of a small scale organic rankine cycle radial Inflow Turbine through multi objective optimization algorithm
    Energy, 2017
    Co-Authors: Ayad Al Jubori, Raya Aldadah, Saad Mahmoud
    Abstract:

    An effective methodology that encompasses a mean-line design, three-dimensional CFD analysis and optimization and ORC system modelling of the small-scale ORC radial-Inflow Turbine is presented. Three-dimensional CFD analysis and a multi-objective optimization algorithm were achieved using ANSYS®17 CFX and Design Exploration based on 3D RANS with a k-omega SST turbulence model. The 3D optimization technique combines a design of the experiment, a response surface method and multi-objective method. The optimization of the blade geometry was performed using 20 design points for both nozzle and rotor blades, based on the B-splines’ technique to represent the blade angles and thickness distribution. The number of blades and rotor tip clearance were included as design parameters. The isentropic efficiency and power output were introduced as an optimization objective with two organic working fluids, namely isopentane and R245fa. The results of the optimized geometry with R245fa showed that the Turbine's and cycle's thermal efficiencies were higher by 13.95% and 17.38% respectively, compared with a base-line design with a maximum power output of 5.415 kW. Such methodology is proved to be effective as it allows the enhancing of the Turbine's and the ORC's system performance throughout to find the optimum blade shape of the Turbine stage.

  • development and experimental study of a small scale compressed air radial Inflow Turbine for distributed power generation
    Applied Thermal Engineering, 2017
    Co-Authors: Kiyarash Rahbar, Saad Mahmoud, Raya Aldadah, Nima Moazami, Seyed Mirhadizadeh
    Abstract:

    Abstract With ever increasing demand on energy, disturbed power generation utilizing efficient technologies such as compressed air energy storage (CAES) and organic Rankine cycle (ORC) are receiving growing attention. Expander for such systems is a key component and its performance has substantial effects on overall system efficiency. This study addresses such component by proposing an effective and comprehensive methodology for developing a small-scale radial Inflow Turbine (RIT). The methodology consists of 1-D modelling, 3-D aerodynamic investigation and structural analysis, manufacturing with pioneering technique and experimental testing for validation. The proposed 1-D modelling was very effective in determining the primary geometry and performance of Turbine based on parametric studies of Turbine input design variables. However with CFD analysis, it was shown that more efficient Turbine geometry can be achieved that not only provides more realistic Turbine performance by capturing the 3-D fluid flow behaviour but also improves Turbine efficiency with the aid of parametric studies of Turbine geometry parameters. Turbine efficiency was improved from 81.3% obtained from 1-D modelling to 84.5% obtained by CFD. Accuracy of the CFD model was assessed by conducting experiments on the RIT manufactured with stereolithography technique. The CFD model can predict Turbine efficiency and power with accuracy of ±16% and ±13% respectively for a wide range of tested operating conditions. Such results highlights the effectiveness of the proposed methodology and the CFD model can be used as benchmarking model for analyses of small-scale RITs. Besides, it was shown that for such applications, the novel manufacturing technique and employed material are very effective for producing prototypes that assist design decisions and validation of CFD model with reasonable accuracy at reasonable cost and in timely manner.

  • low grade heat driven adsorption system for cooling and power generation with small scale radial Inflow Turbine
    Applied Energy, 2016
    Co-Authors: Fadhel Noraldeen Almousawi, Raya Aldadah, Saad Mahmoud
    Abstract:

    Adsorption system is a promising technology that can exploit the abundant low grade heat sources (∼150°C) from renewables like solar, geothermal and industrial waste heat leading to reduction of fossil fuel consumption and CO2 emissions. In this work, the effect of using advanced adsorbent materials like AQSOA-Z02 zeolite (SAPO-34) and Metal Organic Framework (MOF) like MIL101Cr and Aluminium fumarate on power and cooling performance compared to that of commonly used silica-gel was investigated using water as refrigerant. A mathematical model for a two bed adsorption cooling cycle has been developed with the cycle modified to produce power by incorporating an expander between the desorber and the condenser. Results showed that it is possible to produce power and cooling simultaneously without affecting the cooling output. Results also showed that for the four pairs used as the heat source temperature increases, the cooling capacity and power generated increase. As the condenser cooling temperature increases, the cooling effect and power output will decrease while for the chilled water temperature, the cooling capacity and power generated increased as the chilled temperature increased. Also, it is shown that SAPO-34 achieved the maximum average specific power generation (SP) and specific cooling power (SCP) of 67W/kgads and 622W/kgads respectively. A detailed CFD modelling has shown that a small-scale steam radial Inflow Turbine with mass flow rate of 0.0046kg/s generated using 8.55kg/bed of SAPO-34 adsorbent with heat source temperature of 160°C can achieve efficiency of 82% and power output of 785W.

  • modelling and optimization of organic rankine cycle based on a small scale radial Inflow Turbine
    Energy Conversion and Management, 2015
    Co-Authors: Kiyarash Rahbar, Saad Mahmoud, Raya Aldadah, Nima Moazami
    Abstract:

    Abstract In most of the organic Rankine cycle (ORC) studies, constant expander efficiency is considered for a wide range of cycle operating conditions and for various working fluids. This study presents an optimized modelling approach for the ORC based on radial Inflow Turbine, where the constant expander efficiency is replaced by dynamic efficiency that is unique for each set of cycle operating conditions and working fluid properties. Considering the size and performance of the ORC, the model was used to identify the key input variables that have significant effects on the Turbine overall size and the cycle net electric power output. These parameters were then included in the optimization process using the DIRECT algorithm to maximize the ratio of cycle net electric power output to the Turbine overall size (objective function) for six organic fluids. Results showed that, dynamic efficiency approach predicted considerable differences in the Turbine efficiencies of various working fluids. The maximum difference of 6.13% between the Turbine efficiencies of R245fa and isobutane was predicted. Also the optimization results showed that, the maximum objective function of 0.5748 kW/mm was achieved by isobutane with the cycle net electric power output and the Turbine overall size of 90.3 kW and 157.2 mm respectively. Such results are better than the other studies and highlight the potential of the optimization technique to further improve the performance and reduce the size of the ORC based on small-scale radial Turbines.

Jian Song - One of the best experts on this subject based on the ideXlab platform.

  • thermodynamic and economic investigations of transcritical co2 cycle systems with integrated radial Inflow Turbine performance predictions
    Applied Thermal Engineering, 2020
    Co-Authors: Jian Song, C Gu, Xiaoya Li, Hua Tian, Christos N Markides
    Abstract:

    Abstract Transcritical CO2 (TCO2) cycle systems have emerged as a promising power-generation technology in certain applications. In conventional TCO2-cycle system analyses reported in the literature, the Turbine efficiency, which strongly determines the overall system performance, is generally assumed to be constant. This may lead to suboptimal designs and optimization results. In order to improve the accuracy and reliability of such system analyses and offer insight into how knowledge of these systems from earlier analyses can be interpreted, this paper presents a comprehensive model that couples TCO2-cycle calculations with preliminary Turbine design based on the mean-line method. Turbine design parameters are optimized simultaneously to achieve the highest Turbine efficiency, which replaces the constant Turbine efficiency used in cycle calculations. A case study of heat recovery from an internal combustion engine (ICE) using a TCO2-cycle system with a radial-Inflow Turbine is then considered, with results revealing that the Turbine efficiency is influenced by the system's operating conditions, which in turn has a significant effect on system performance in both thermodynamic and economic terms. A more generalized heat source is then considered to explore more broadly the role of the Turbine in determining TCO2-cycle power-system performance. The more detailed Turbine-design modelling approach allows errors of the order of up to 10–20% in various predictions to be avoided for steady-state calculations, and potentially of an even greater magnitude at off-design operation. The model allows quick preliminary designs of radial-Inflow Turbines and reasonable Turbine performance predictions under various operating conditions, and can be a useful tool for more accurate and reliable thermo-economic studies of TCO2-cycle systems.

  • thermodynamic and economic analysis of a supercritical carbon dioxide s co2 recompression cycle with the radial Inflow Turbine efficiency prediction
    Energy, 2020
    Co-Authors: Aozheng Zhou, Xiaodong Ren, Jian Song
    Abstract:

    Abstract The Turbine is one of the core components of the supercritical carbon dioxide (S–CO2) cycle system. Generally, a radial-Inflow Turbine is adopted for the small volume flow application. The Turbine efficiency is closely related to the cycle parameters. In the previous studies about the S–CO2 cycle, the Turbine efficiency is usually set as a constant value. In our previous studies of Organic Rankine Cycle (ORC), adopting a 1D model predicted Turbine efficiency instead of a constant Turbine efficiency is proved to have significant impacts on the system parameter determination. However, there was few researches about the influence of the Turbine efficiency prediction method on the S–CO2 cycle design or optimization. In this paper, the analysis model of the S–CO2 recompression cycle with a one-dimensional (1D) radial-Inflow Turbine efficiency prediction model is presented, while others components off-design performance predicted models are not considered. The thermodynamic and economic performances of the S–CO2 cycle with the 1D model predicted Turbine efficiency and constant Turbine efficiency are analyzed and compared under different cycle design parameters and heat source conditions. The results indicate that for the S–CO2 cycle design and analysis, a proper constant Turbine efficiency can be used when the heat source mass flow rate is constant. However, for some applications, the heat source mass flow rate is various according to the running time, especially for the low mass flow rate application, a 1D model predicted Turbine efficiency should be used instead of a constant Turbine efficiency.

  • aerodynamic design and numerical analysis of a radial Inflow Turbine for the supercritical carbon dioxide brayton cycle
    Applied Thermal Engineering, 2018
    Co-Authors: Aozheng Zhou, Jian Song, Xuesong Li, C Gu
    Abstract:

    Abstract The supercritical carbon dioxide (S-CO2) Brayton cycle is considered to be one of the most promising power cycles for the future. Its main advantages include compactness, high efficiency, high safety and good environmental friendliness. The system performance depends much on the Turbine, which is one of the core components of the S-CO2 Brayton cycle. Compared to the axial Turbine, the radial Inflow Turbine has a lower cost and more compact structure, and can provide a high operating efficiency under small volume flows. In this study, a design method for an S-CO2 radial Inflow Turbine is proposed and a 1.5-MW S-CO2 radial Inflow Turbine is designed. The three-dimensional (3D) numerical simulation of the designed Turbine is carried out by using ANSYS-CFX commercial software, and the results are in good agreement with the design values. The off-design performance of the Turbine is predicted by using the one-dimensional (1D) model and the 3D numerical simulation. The results are consistent with each other. It means that the proposed design method for the S-CO2 radial Inflow Turbine is reliable.

  • Influence of the radial-Inflow Turbine efficiency prediction on the design and analysis of the Organic Rankine Cycle (ORC) system
    Energy Conversion and Management, 2016
    Co-Authors: Jian Song, Xiaodong Ren
    Abstract:

    Abstract The radial-Inflow Turbine is a common choice for the power output in the Organic Rankine Cycle (ORC) system. Its efficiency is related to the working fluid property and the system operating condition. Generally, the radial-Inflow Turbine efficiency is assumed to be a constant value in the conventional ORC system analysis. Few studies focus on the influence of the radial-Inflow Turbine efficiency selection on the system design and analysis. Actually, the ORC system design and the radial-Inflow Turbine design are coupled with each other. Different thermal parameters of the ORC system would lead to different radial-Inflow Turbine design and then different Turbine efficiency, and vice versa. Therefore, considering the radial-Inflow Turbine efficiency prediction in the ORC system design can enhance its reliability and accuracy. In this paper, a one-dimensional analysis model for the radial-Inflow Turbine in the ORC system is presented. The radial-Inflow Turbine efficiency prediction in this model is based on the velocity triangle and loss models, rather than a constant efficiency assumption. The influence of the working fluid property and the system operating condition on the Turbine performance is evaluated. The thermodynamic analysis of the ORC system with a model predicted Turbine efficiency and a constant Turbine efficiency is conducted and the results are compared with each other. It indicates that the Turbine efficiency selection has a significant influence on the working fluid selection and the system parameter determination.

Xiaodong Ren - One of the best experts on this subject based on the ideXlab platform.

  • thermodynamic and economic analysis of a supercritical carbon dioxide s co2 recompression cycle with the radial Inflow Turbine efficiency prediction
    Energy, 2020
    Co-Authors: Aozheng Zhou, Xiaodong Ren, Jian Song
    Abstract:

    Abstract The Turbine is one of the core components of the supercritical carbon dioxide (S–CO2) cycle system. Generally, a radial-Inflow Turbine is adopted for the small volume flow application. The Turbine efficiency is closely related to the cycle parameters. In the previous studies about the S–CO2 cycle, the Turbine efficiency is usually set as a constant value. In our previous studies of Organic Rankine Cycle (ORC), adopting a 1D model predicted Turbine efficiency instead of a constant Turbine efficiency is proved to have significant impacts on the system parameter determination. However, there was few researches about the influence of the Turbine efficiency prediction method on the S–CO2 cycle design or optimization. In this paper, the analysis model of the S–CO2 recompression cycle with a one-dimensional (1D) radial-Inflow Turbine efficiency prediction model is presented, while others components off-design performance predicted models are not considered. The thermodynamic and economic performances of the S–CO2 cycle with the 1D model predicted Turbine efficiency and constant Turbine efficiency are analyzed and compared under different cycle design parameters and heat source conditions. The results indicate that for the S–CO2 cycle design and analysis, a proper constant Turbine efficiency can be used when the heat source mass flow rate is constant. However, for some applications, the heat source mass flow rate is various according to the running time, especially for the low mass flow rate application, a 1D model predicted Turbine efficiency should be used instead of a constant Turbine efficiency.

  • Aerodynamic optimization of a high-expansion ratio organic radial-Inflow Turbine
    Journal of Mechanical Science and Technology, 2016
    Co-Authors: Xiaodong Ren
    Abstract:

    Given that the radial-Inflow Turbine is a critical component of the Organic Rankine cycle system, its performance substantially influences system capacity. This paper established an optimization framework for the radial-Inflow Turbine is established with the combination of a computational fluid dynamics software, a non-uniform rational B-spline parameterization method, and an optimization strategy. The nozzle, meridional flow path, and blade profile of a 500 kW Turbine were optimized. Results show that nozzle blade and impeller optimization leads to a 0.34 % and about 0.71 % increase in Turbine efficiency, respectively. After optimization, the flow state in the Turbine was good, and the flow separation almost disappeared.

  • Influence of the radial-Inflow Turbine efficiency prediction on the design and analysis of the Organic Rankine Cycle (ORC) system
    Energy Conversion and Management, 2016
    Co-Authors: Jian Song, Xiaodong Ren
    Abstract:

    Abstract The radial-Inflow Turbine is a common choice for the power output in the Organic Rankine Cycle (ORC) system. Its efficiency is related to the working fluid property and the system operating condition. Generally, the radial-Inflow Turbine efficiency is assumed to be a constant value in the conventional ORC system analysis. Few studies focus on the influence of the radial-Inflow Turbine efficiency selection on the system design and analysis. Actually, the ORC system design and the radial-Inflow Turbine design are coupled with each other. Different thermal parameters of the ORC system would lead to different radial-Inflow Turbine design and then different Turbine efficiency, and vice versa. Therefore, considering the radial-Inflow Turbine efficiency prediction in the ORC system design can enhance its reliability and accuracy. In this paper, a one-dimensional analysis model for the radial-Inflow Turbine in the ORC system is presented. The radial-Inflow Turbine efficiency prediction in this model is based on the velocity triangle and loss models, rather than a constant efficiency assumption. The influence of the working fluid property and the system operating condition on the Turbine performance is evaluated. The thermodynamic analysis of the ORC system with a model predicted Turbine efficiency and a constant Turbine efficiency is conducted and the results are compared with each other. It indicates that the Turbine efficiency selection has a significant influence on the working fluid selection and the system parameter determination.

  • Investigation of the organic Rankine cycle (ORC) system and the radial-Inflow Turbine design
    Applied Thermal Engineering, 2016
    Co-Authors: Xiaodong Ren
    Abstract:

    Abstract Energy and environment issue set utilizing low-grade heat noticed. Organic Rankine Cycle (ORC) has been demonstrated to be a promising technology to recover waste heat. As a critical component of ORC system, the Turbine selection has an enormous influence on the system performance. This paper carries out a study on the thermodynamic analysis of ORC system and the aerodynamic design of an organic radial Turbine. The system performance is evaluated with various working fluids. The aerodynamic design of the organic radial-Inflow Turbine is focused due to the high molecule weight and the low sound speed of the organic working fluid. An aerodynamic and profile design system is developed. A radial-Inflow Turbine with R123 as the working fluid is designed and the numerical analysis is conducted. The simulation results indicate that the shock wave caused by the high expansion ratio in the nozzle is well controlled. Compared with the one-dimensional design results, the performance of the radial-Inflow Turbine in this paper reaches the design requirements.

Raya Aldadah - One of the best experts on this subject based on the ideXlab platform.

  • performance enhancement of a small scale organic rankine cycle radial Inflow Turbine through multi objective optimization algorithm
    Energy, 2017
    Co-Authors: Ayad Al Jubori, Raya Aldadah, Saad Mahmoud
    Abstract:

    An effective methodology that encompasses a mean-line design, three-dimensional CFD analysis and optimization and ORC system modelling of the small-scale ORC radial-Inflow Turbine is presented. Three-dimensional CFD analysis and a multi-objective optimization algorithm were achieved using ANSYS®17 CFX and Design Exploration based on 3D RANS with a k-omega SST turbulence model. The 3D optimization technique combines a design of the experiment, a response surface method and multi-objective method. The optimization of the blade geometry was performed using 20 design points for both nozzle and rotor blades, based on the B-splines’ technique to represent the blade angles and thickness distribution. The number of blades and rotor tip clearance were included as design parameters. The isentropic efficiency and power output were introduced as an optimization objective with two organic working fluids, namely isopentane and R245fa. The results of the optimized geometry with R245fa showed that the Turbine's and cycle's thermal efficiencies were higher by 13.95% and 17.38% respectively, compared with a base-line design with a maximum power output of 5.415 kW. Such methodology is proved to be effective as it allows the enhancing of the Turbine's and the ORC's system performance throughout to find the optimum blade shape of the Turbine stage.

  • development and experimental study of a small scale compressed air radial Inflow Turbine for distributed power generation
    Applied Thermal Engineering, 2017
    Co-Authors: Kiyarash Rahbar, Saad Mahmoud, Raya Aldadah, Nima Moazami, Seyed Mirhadizadeh
    Abstract:

    Abstract With ever increasing demand on energy, disturbed power generation utilizing efficient technologies such as compressed air energy storage (CAES) and organic Rankine cycle (ORC) are receiving growing attention. Expander for such systems is a key component and its performance has substantial effects on overall system efficiency. This study addresses such component by proposing an effective and comprehensive methodology for developing a small-scale radial Inflow Turbine (RIT). The methodology consists of 1-D modelling, 3-D aerodynamic investigation and structural analysis, manufacturing with pioneering technique and experimental testing for validation. The proposed 1-D modelling was very effective in determining the primary geometry and performance of Turbine based on parametric studies of Turbine input design variables. However with CFD analysis, it was shown that more efficient Turbine geometry can be achieved that not only provides more realistic Turbine performance by capturing the 3-D fluid flow behaviour but also improves Turbine efficiency with the aid of parametric studies of Turbine geometry parameters. Turbine efficiency was improved from 81.3% obtained from 1-D modelling to 84.5% obtained by CFD. Accuracy of the CFD model was assessed by conducting experiments on the RIT manufactured with stereolithography technique. The CFD model can predict Turbine efficiency and power with accuracy of ±16% and ±13% respectively for a wide range of tested operating conditions. Such results highlights the effectiveness of the proposed methodology and the CFD model can be used as benchmarking model for analyses of small-scale RITs. Besides, it was shown that for such applications, the novel manufacturing technique and employed material are very effective for producing prototypes that assist design decisions and validation of CFD model with reasonable accuracy at reasonable cost and in timely manner.

  • low grade heat driven adsorption system for cooling and power generation with small scale radial Inflow Turbine
    Applied Energy, 2016
    Co-Authors: Fadhel Noraldeen Almousawi, Raya Aldadah, Saad Mahmoud
    Abstract:

    Adsorption system is a promising technology that can exploit the abundant low grade heat sources (∼150°C) from renewables like solar, geothermal and industrial waste heat leading to reduction of fossil fuel consumption and CO2 emissions. In this work, the effect of using advanced adsorbent materials like AQSOA-Z02 zeolite (SAPO-34) and Metal Organic Framework (MOF) like MIL101Cr and Aluminium fumarate on power and cooling performance compared to that of commonly used silica-gel was investigated using water as refrigerant. A mathematical model for a two bed adsorption cooling cycle has been developed with the cycle modified to produce power by incorporating an expander between the desorber and the condenser. Results showed that it is possible to produce power and cooling simultaneously without affecting the cooling output. Results also showed that for the four pairs used as the heat source temperature increases, the cooling capacity and power generated increase. As the condenser cooling temperature increases, the cooling effect and power output will decrease while for the chilled water temperature, the cooling capacity and power generated increased as the chilled temperature increased. Also, it is shown that SAPO-34 achieved the maximum average specific power generation (SP) and specific cooling power (SCP) of 67W/kgads and 622W/kgads respectively. A detailed CFD modelling has shown that a small-scale steam radial Inflow Turbine with mass flow rate of 0.0046kg/s generated using 8.55kg/bed of SAPO-34 adsorbent with heat source temperature of 160°C can achieve efficiency of 82% and power output of 785W.

  • modelling and optimization of organic rankine cycle based on a small scale radial Inflow Turbine
    Energy Conversion and Management, 2015
    Co-Authors: Kiyarash Rahbar, Saad Mahmoud, Raya Aldadah, Nima Moazami
    Abstract:

    Abstract In most of the organic Rankine cycle (ORC) studies, constant expander efficiency is considered for a wide range of cycle operating conditions and for various working fluids. This study presents an optimized modelling approach for the ORC based on radial Inflow Turbine, where the constant expander efficiency is replaced by dynamic efficiency that is unique for each set of cycle operating conditions and working fluid properties. Considering the size and performance of the ORC, the model was used to identify the key input variables that have significant effects on the Turbine overall size and the cycle net electric power output. These parameters were then included in the optimization process using the DIRECT algorithm to maximize the ratio of cycle net electric power output to the Turbine overall size (objective function) for six organic fluids. Results showed that, dynamic efficiency approach predicted considerable differences in the Turbine efficiencies of various working fluids. The maximum difference of 6.13% between the Turbine efficiencies of R245fa and isobutane was predicted. Also the optimization results showed that, the maximum objective function of 0.5748 kW/mm was achieved by isobutane with the cycle net electric power output and the Turbine overall size of 90.3 kW and 157.2 mm respectively. Such results are better than the other studies and highlight the potential of the optimization technique to further improve the performance and reduce the size of the ORC based on small-scale radial Turbines.

Nima Moazami - One of the best experts on this subject based on the ideXlab platform.

  • development and experimental study of a small scale compressed air radial Inflow Turbine for distributed power generation
    Applied Thermal Engineering, 2017
    Co-Authors: Kiyarash Rahbar, Saad Mahmoud, Raya Aldadah, Nima Moazami, Seyed Mirhadizadeh
    Abstract:

    Abstract With ever increasing demand on energy, disturbed power generation utilizing efficient technologies such as compressed air energy storage (CAES) and organic Rankine cycle (ORC) are receiving growing attention. Expander for such systems is a key component and its performance has substantial effects on overall system efficiency. This study addresses such component by proposing an effective and comprehensive methodology for developing a small-scale radial Inflow Turbine (RIT). The methodology consists of 1-D modelling, 3-D aerodynamic investigation and structural analysis, manufacturing with pioneering technique and experimental testing for validation. The proposed 1-D modelling was very effective in determining the primary geometry and performance of Turbine based on parametric studies of Turbine input design variables. However with CFD analysis, it was shown that more efficient Turbine geometry can be achieved that not only provides more realistic Turbine performance by capturing the 3-D fluid flow behaviour but also improves Turbine efficiency with the aid of parametric studies of Turbine geometry parameters. Turbine efficiency was improved from 81.3% obtained from 1-D modelling to 84.5% obtained by CFD. Accuracy of the CFD model was assessed by conducting experiments on the RIT manufactured with stereolithography technique. The CFD model can predict Turbine efficiency and power with accuracy of ±16% and ±13% respectively for a wide range of tested operating conditions. Such results highlights the effectiveness of the proposed methodology and the CFD model can be used as benchmarking model for analyses of small-scale RITs. Besides, it was shown that for such applications, the novel manufacturing technique and employed material are very effective for producing prototypes that assist design decisions and validation of CFD model with reasonable accuracy at reasonable cost and in timely manner.

  • modelling and optimization of organic rankine cycle based on a small scale radial Inflow Turbine
    Energy Conversion and Management, 2015
    Co-Authors: Kiyarash Rahbar, Saad Mahmoud, Raya Aldadah, Nima Moazami
    Abstract:

    Abstract In most of the organic Rankine cycle (ORC) studies, constant expander efficiency is considered for a wide range of cycle operating conditions and for various working fluids. This study presents an optimized modelling approach for the ORC based on radial Inflow Turbine, where the constant expander efficiency is replaced by dynamic efficiency that is unique for each set of cycle operating conditions and working fluid properties. Considering the size and performance of the ORC, the model was used to identify the key input variables that have significant effects on the Turbine overall size and the cycle net electric power output. These parameters were then included in the optimization process using the DIRECT algorithm to maximize the ratio of cycle net electric power output to the Turbine overall size (objective function) for six organic fluids. Results showed that, dynamic efficiency approach predicted considerable differences in the Turbine efficiencies of various working fluids. The maximum difference of 6.13% between the Turbine efficiencies of R245fa and isobutane was predicted. Also the optimization results showed that, the maximum objective function of 0.5748 kW/mm was achieved by isobutane with the cycle net electric power output and the Turbine overall size of 90.3 kW and 157.2 mm respectively. Such results are better than the other studies and highlight the potential of the optimization technique to further improve the performance and reduce the size of the ORC based on small-scale radial Turbines.