Constrained multi-objective optimization of radial expanders in organic Rankine cycles by firefly algorithm

Bahadormanesh, Nikrouz; Rahat, Shayan; Yarali, Milad

doi:10.1016/j.enconman.2017.06.070

Cited by 39 publications

(13 citation statements)

References 40 publications

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“…Moreover, the total-to-static efficiency of the turbine is calculated (Equation (17)) applying the enthalpy loss correlations. The calculation of the selected ORC operating parameters and performance indicators (Equations (23)- (25)) is made in the next step. After that, the multi-objective optimization problem is defined and solved, using non-dominated sorting genetic algorithm-II (NSGA-II) [22], the optimization tool that is embedded in MATLAB.…”

Section: Algorithm and Research Toolsmentioning

confidence: 99%

“…The turbine total-to-static efficiency η T is calculated iteratively based on the results of the radial-inflow turbine design and enthalpy loss ∆h loss correlations. For a detailed description of the procedures similar to the model applied in this study, see [16,23] or some recent papers [24,25]. The general equation used to calculate η T is the following:…”

Section: Radial-inflow Turbine Designmentioning

confidence: 99%

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A Novel Exergy Indicator for Maximizing Energy Utilization in Low-Temperature ORC

Jankowski

Borsukiewicz-Gozdur

2020

Energies

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In the last decade, particular attention has been paid to the organic Rankine cycle (ORC) power plant, a technology that implements a classical steam Rankine cycle using low-boiling fluid of organic origin. Depending on the specific application and the choice of the designer, the ORC can be optimized using one or several criteria. The selected objectives reflect various system performance aspects, such as: thermodynamic, economic, environmental or other. In this study, a novel criterion called exergy utilization index (XUI) is defined and used to maximize the utilization of an energy source in the ORC system. The maximization of the proposed indicator is equivalent to bring the heat carrier outlet temperature to the ambient temperature as close as possible. In the studied case, the XUI is applied along with the total heat transfer area of the system, and the multi-objective optimization is performed in order to determine the optimal operating conditions of the ORC. Moreover, to reveal a relationship between the XUI and important ORC performance indicators, a parametric study is conducted. Based on the results, it has been found that high values of the XUI (~80%) correspond to optimal values of exergy-based indicators such as: exergy efficiency, waste exergy ratio, environmental effect factor or exergetic sustainability index. Furthermore, the values of the XUI = 60%–80% are associated with beneficial economic characteristics reflected in a low payback period (<11.3 years). When considering the ecological aspect, the maximization of XUI has resulted in minimization of exergy waste to the environment. In general, the simple formulation and straightforward meaning make the XUI a particularly useful indicator for the preliminary evaluation and design of the ORC. Furthermore, the comparative analysis with respect to other well-known performance indicators has shown that it has a potential to be successfully applied as the objective function in the optimization of ORC power plants.

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Section: Algorithm and Research Toolsmentioning

confidence: 99%

Section: Radial-inflow Turbine Designmentioning

confidence: 99%

A Novel Exergy Indicator for Maximizing Energy Utilization in Low-Temperature ORC

Jankowski

Borsukiewicz-Gozdur

2020

Energies

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“…Basically, for the ORC system within the power range of 50-5000 kW, an axial turbine and a radial-inflow turbine are proposed as two options [23]. The radial-inflow turbine presents an excellent aerodynamic performance, as it can deal with large enthalpy drops with relatively low peripheral speeds, has higher single-stage expansion ratio, and good off-design performance [19][20][21]. In this paper, the heat source inlet temperature is at a relatively high level (523.15 K), the radial-inflow turbine was selected as the expander to deal with the high expansion ratio.…”

Section: Radial-inflow Turbine Efficiency Prediction Modelmentioning

confidence: 99%

“…They found that there is a considerable difference in turbine efficiency for different operating conditions. Bahadormanesh et al [20] combined the ORC thermodynamic model with a radial-inflow turbine design procedure. The firefly algorithm was used to optimize the thermal efficiency and the size parameter.…”

Section: Introductionmentioning

confidence: 99%

An Improved Analysis Method for Organic Rankine Cycles Based on Radial-Inflow Turbine Efficiency Prediction

Han

Jia

et al. 2018

Applied Sciences

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The organic Rankine cycle (ORC) has been demonstrated to be an effective method for converting low-grade heat energy into electricity. This paper proposes an improved analysis method for the ORC system. A coupling model of the ORC system with a radial-inflow turbine efficiency prediction model is presented. Multi-objective optimization was conducted for a constant turbine efficiency ORC system (ORCCTE) and a predicted turbine efficiency ORC system (ORCDTE), and the optimization results were compared. Additionally, a sensitivity analysis was conducted with respect to the heat source temperature and the ambient temperature. It can be found that the predicted turbine efficiency decreases with the increasing evaporation temperature, and increases with the increasing condensation temperature. The turbine efficiency is not constant and it varies with operating conditions. The distribution of the Pareto frontier for ORCCTE system and ORCCTE system is different. Compared with the ORCCTE system, the ORCDTE system has a lower optimal evaporation temperature, but a higher optimal condensation temperature. The deviation between the predicted turbine efficiency and the constant turbine efficiency increases with the increasing heat source temperature but decreases with the increasing ambient temperature. Thus, the difference in the theoretical analysis results between ORCCTE system and ORCDTE system increases with the increasing heat source temperature but decreases with the increasing ambient temperature.

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“…The power and efficiency characteristics of the designed centrifugal turbines were assessed based on the CFD simulation methods. In addition, some researchers [20][21][22][23][24] coupled the one dimensional model of the radial-inflow turbine with the thermodynamic model of the ORC system to investigate the influence of turbine efficiency on the ORC system parameters optimization and working fluids selection.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Effects of Blade Installation Angle and Blade Number on Radial-Inflow Turbine Stator Flow Performance

Han

Jia

et al. 2018

Energies

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Organic Rankine cycle (ORC) is a reliable technology to recover low-grade heat sources. The radial-inflow turbine is a critical component, which has a significant influence on the overall efficiency of ORC system. This study investigates the effects of the blade installation angle and blade number on the flow performance of radial-inflow turbine stator. R245fa and toluene were selected as the working fluids in the low and high temperature range, respectively. Two-dimensional stator blades model for the two working fluids were established, and numerical simulation was conducted through Computational Fluid Dynamics (CFD) software. The results show that for low temperature working fluid R245fa, when the installation angle is 32° and blade number is 22, the distribution of static pressure along the stator blade has no obvious pressure fluctuation, and the flow loss is least. Meanwhile, the stator blade obtained the optimal performance. For high temperature working fluid toluene, when the installation angle is 28° and blade number is 32, the average outlet temperature is the lowest, while the average outlet velocity is the largest. The flow state is well and smooth, and the remarkable flow separation and shock wave are not present. Moreover, the stator blade for R245fa has a larger chord length, cascade inlet diameter, and cascade outside diameter but a lower blade number compared to toluene.

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Constrained multi-objective optimization of radial expanders in organic Rankine cycles by firefly algorithm

Cited by 39 publications

References 40 publications

A Novel Exergy Indicator for Maximizing Energy Utilization in Low-Temperature ORC

A Novel Exergy Indicator for Maximizing Energy Utilization in Low-Temperature ORC

An Improved Analysis Method for Organic Rankine Cycles Based on Radial-Inflow Turbine Efficiency Prediction

Analysis of the Effects of Blade Installation Angle and Blade Number on Radial-Inflow Turbine Stator Flow Performance

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