Parametric analysis of organic Rankine cycle based on a radial turbine for low-grade waste heat recovery

Dong, Bensi; Xu, Guoqiang; Li, Tingting; Luo, Xianglong; Quan, Yongkai

doi:10.1016/j.applthermaleng.2017.07.046

Cited by 18 publications

(14 citation statements)

References 27 publications

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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%

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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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Section: Radial-inflow Turbine Efficiency Prediction Modelmentioning

confidence: 99%

“…The firefly algorithm was used to optimize the thermal efficiency and the size parameter. Dong et al [21] proposed an optimized coupling model of an ORC system with a radial-inflow turbine and investigated the impact of heat source outlet temperature on turbine efficiency and system performance.…”

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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“…Galloni et al performed experimental investigation of a mini‐ORC with a hot source temperature between 75 and 90°C based on R245fa as the working fluid, which can reach a thermal efficiency of approximately 9%, a specific work equal to approximately 20 kJ/kg, and provide an output power somewhat greater than 1 kW. Dong et al established an ORC system with the mean‐line modeling of a radial turbine coupling model for evaluating the heat source outlet temperature and the performance of the radial turbo expander. In the simulation of different working fluids, when the outlet temperature is lower than 120°C, the use of R245fa output power is the highest.…”

Section: Introductionmentioning

confidence: 99%

Simulation study on the flow field of guide vane and impeller of turbo expander

Liu

Wang

Zhang

et al. 2019

Energy Science & Engineering

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In the face of the current energy shortage, organic Rankine cycle (ORC) technology is a way to make efficient use of energy, especially geothermal energy. As the core component of an ORC system, a turbo expander can achieve a high conversion efficiency for geothermal energy and has good development prospects. For low temperature geothermal energy such as 95°C water, R245fa could be chosen as the working fluid. Through preliminary thermal calculations and the MATLAB programming method, the main thermal performance parameters and the aerodynamic parameters, structural parameters, and three‐dimensional modeling of the guide vane and impeller were obtained. The design of the turbo expander was modeled and meshed by the Workbench module using the ANSYS software, and the internal flow path of the expander was numerically simulated by the CFX module. The results showed that there was a small range of wake loss at the trailing edge of the vane flow; impact loss and wake loss occurred at the leading and trailing edges of the impeller blades. At the 30% relative chord strength of the impeller, there was excessive expansion, resulting in a local low‐pressure area and a secondary flow from the hub to the rim.

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“…Compared to conventional working fluids, organic working fluids invariably possess large molecular weight, high density, and low critical temperature and pressure. Therefore, these special physical properties lead to some distinguished characteristics such as high Mach number at the stator outlet, supersonic flow in the stator, a small size, and a high rotational speed [16]. These characteristics limit the radial-inflow turbine efficiency, which further lowers the ORC system efficiency.…”

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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Parametric analysis of organic Rankine cycle based on a radial turbine for low-grade waste heat recovery

Cited by 18 publications

References 27 publications

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

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

Simulation study on the flow field of guide vane and impeller of turbo expander

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

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