# Development of 180 kW Organic Rankine Cycle (ORC) with a High-Efficiency Two-Stage Axial Turbine

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## Abstract

**:**

## 1. Introduction

## 2. Organic Rankine Cycle

#### 2.1. Thermodynamic Description of the Rankine Cycle

#### 2.2. Mathematical Formulation

#### 2.3. Selection of the Working Fluid

## 3. Mean-Line Design of the Turbine

#### 3.1. Description of the Mean-Line Design

#### 3.2. Design Parameters and Velocity Triangle

#### 3.3. Loss Models

## 4. Flowchart of Turbine Design

^{−3}was selected as the convergence criterion. The GRG nonlinear algorithm is significantly affected by the initial values, and the calculation most likely will stop at a region other than the global optimum solution. However, the algorithm is a powerful tool in the turbine mean-line design because it can rapidly identify a local optimum solution near the initial conditions. The reliability of the GRG nonlinear algorithm applied to the in-house code was verified because it used commercial code provided by Microsoft Excel 2016.

## 5. Numerical Analysis Procedures

^{−3}. The equations of the SST k–ω turbulent model are as follows:

## 6. Results and Discussion

#### 6.1. Validation

#### 6.2. Mean-Line Design

#### 6.3. Numerical Analysis

#### 6.4. ORC Thermal Efficiency

## 7. Conclusions

## Author Contributions

## Funding

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 7.**Turbine efficiency comparison between the mean-line design results and the experimental results [53].

**Figure 13.**Turbine total-to-static efficiency comparison between the numerical analysis results and the mean-line design results.

**Figure 14.**Turbine total-to-static efficiency versus pressure ratio for various rotational velocities.

Authors | Turbine | $\mathbf{ORC}\mathit{\eta}$ [%] | [Ref.] | |||
---|---|---|---|---|---|---|

Type (Stage No.) | $\mathit{\Omega}$ [rpm] | $\mathit{\eta}$ [%] | $\dot{\mathit{W}}$ [kW] | |||

Li et al. | Axial (1) | 1600–3600 | 58.53 | 6.07 | 6.15–7.98 | [5] |

Peng et al. | Axial (1–3) | 150,000–190,000 | 75.8–81.6 | 18.34–19.0 | - | [6] |

Fu et al. | Axial (1) | 12,386 | 63.7 | 219.5 ± 5.5 | 7.94 | [7] |

Pei et al. | Radial (1) | 20,000–25,000 | 65 | 1.36 | 6.8 | [8] |

Kang | Radial (1) | 20,000 | 78.7 | 32.7 | 5.22 | [9] |

Klonowicz et al. | Axial (1) | 3264 | 53 ± 2 | 9.9 ± 0.2 | - | [10] |

Giovannelli et al. | Radial (2) | 23,000–27,000 | 80 | 71.2 | - | [11] |

Li et al. | Axial (1) | 3010 | 53 | 6.57 | - | [12] |

Jubori et al. | Axial (2) | 30,000 | 78.30–83.94 | 11.06–16.04 | 10.5–14.19 | [13] |

Parameters | Value |
---|---|

Working fluid | R245fa |

Inlet temperature, Tin [°C] | 85 |

Inlet total pressure, Pin [MPa] | 0.75 |

Power output [kW] | 180 |

Evaporator & Condenser | Heat exchanger |

Pump efficiency, ${\eta}_{p}$ | 0.75 |

Turbine type | Axial-flow |

Number of turbine stage | 2 |

Turbine rotational speed [RPM] | 12,000 |

Generator efficiency | 0.98 |

Hot source temperature, ${T}_{H}$ [°C] | 100 |

Cold source temperature, ${T}_{C}$ [°C] | 20 |

**Table 3.**Properties of working fluid R245fa [31].

Molecular Mass | Critical Temperature | Critical Pressure | Evaporation Temperature (at 1 atm) | ODP | GWP |
---|---|---|---|---|---|

134.05 g/mol | 154.01 °C | 36.51 bar | 15.25 °C | 0 | 1030 |

Design Parameters | Value | |
---|---|---|

First-Stage | Second-Stage | |

Flow coefficient, $\Phi $ | 0.27 | |

Loading coefficient, $\Psi $ | 1.18 | |

Degree of reaction, ${\rm Z}$ | 0.50 | |

Blade mean radius, ${r}_{m}$ [mm] | 70.89 | |

Number of blades | 59 | 63 |

Axial chord, ${C}_{x}$ [mm] | 9.23 | 8.13 |

Chord, C [mm] | 11.28 | 10.57 |

Pitch, S [mm] | 7.92 | 7.41 |

Zweifel blade loading coefficient | 1.03 | 1.00 |

Tip clearance height [mm] | 0.50 | |

Trailing edge thickness [mm] | 0.142 | 0.135 |

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**MDPI and ACS Style**

Sim, J.-B.; Yook, S.-J.; Kim, Y.W.
Development of 180 kW Organic Rankine Cycle (ORC) with a High-Efficiency Two-Stage Axial Turbine. *Energies* **2023**, *16*, 7112.
https://doi.org/10.3390/en16207112

**AMA Style**

Sim J-B, Yook S-J, Kim YW.
Development of 180 kW Organic Rankine Cycle (ORC) with a High-Efficiency Two-Stage Axial Turbine. *Energies*. 2023; 16(20):7112.
https://doi.org/10.3390/en16207112

**Chicago/Turabian Style**

Sim, Jung-Bo, Se-Jin Yook, and Young Won Kim.
2023. "Development of 180 kW Organic Rankine Cycle (ORC) with a High-Efficiency Two-Stage Axial Turbine" *Energies* 16, no. 20: 7112.
https://doi.org/10.3390/en16207112