Supercritical CO2 Radial Turbine Design Performance as a Function of Turbine Size Parameters

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Jianhui Qi ◽  
Thomas Reddell ◽  
Kan Qin ◽  
Kamel Hooman ◽  
Ingo H. J. Jahn
Keyword(s):  
Supercritical Co2 ◽  
Design Space ◽  
Waste Heat ◽  
Small Scale ◽  
Scaling Effects ◽  
Radial Turbine ◽  
Improved Performance ◽  
Turbine Design ◽  
Line Design ◽  
Selection Of

Supercritical CO2 (sCO2) cycles are considered as a promising technology for next generation concentrated solar thermal, waste heat recovery, and nuclear applications. Particularly at small scale, where radial inflow turbines can be employed, using sCO2 results in both system advantages and simplifications of the turbine design, leading to improved performance and cost reductions. This paper aims to provide new insight toward the design of radial turbines for operation with sCO2 in the 100–200 kW range. The quasi-one-dimensional mean-line design code topgen is enhanced to explore and map the radial turbine design space. This mapping process over a state space defined by head and flow coefficients allows the selection of an optimum turbine design, while balancing performance and geometrical constraints. By considering three operating points with varying power levels and rotor speeds, the effect of these on feasible design space and performance is explored. This provides new insight toward the key geometric features and operational constraints that limit the design space as well as scaling effects. Finally, review of the loss break-down of the designs elucidates the importance of the respective loss mechanisms. Similarly, it allows the identification of design directions that lead to improved performance. Overall, this work has shown that turbine design with efficiencies in the range of 78–82% is possible in this power range and provides insight into the design space that allows the selection of optimum designs.

Supercritical CO2 Radial Turbine Design Performance as a Function of Turbine Size Parameters

2016 ◽  
Author(s):  
Jianhui Qi ◽  
Thomas Reddell ◽  
Kan Qin ◽  
Kamel Hooman ◽  
Ingo H. J. Jahn
Keyword(s):  
Supercritical Co2 ◽  
Design Space ◽  
Thermal Power ◽  
Research Direction ◽  
Geometric Constraints ◽  
Solar Thermal ◽  
Small Scale ◽  
Design Code ◽  
Radial Turbine ◽  
Turbine Design

Supercritical CO2 (sCO2) radial inflow turbine are an enabling technology for small scale concentrated solar thermal power. They are a research direction of the Australian Solar Thermal Research Initiative (ASTRI). This study uses the 1D meanline design code TOPGEN, to explore the radial turbine design space under consideration of sCO2 real gas properties. TOPGEN maps a parametric design space defined by flow and head coefficient. The preliminary design code is used explore the feasibility, geometry and performance of sCO2 turbines in the 100kW to 200kW range in order to assess feasible design spaces and to investigate turbine scaling. Turbines are scaled with respect to power, while maintaining specific speed constant and with respect to speed. This analysis shows that both scaling approaches change the feasible design space and that both geometric constraints such as blade height or operational constraints such as blade natural frequency can significantly limit the design space. Detailed analysis of four shortlisted designs shows that turbine efficiencies close to 85% can be attained for 100kW and 200kW output powers, even when operating at reduced rotor speeds. This work provides new insight towards the design of small scale radial turbines for operation with sCO2 and highlights scaling issues that may arise when testing sub-scale turbine prototypes.

Preliminary Design of Small-Scale Supercritical CO2 Radial Inflow Turbines

2020 ◽  
Vol 142 (2) ◽  
Author(s):  
Tina Unglaube ◽  
Hsiao-Wei D. Chiang
Keyword(s):  
Optimum Design ◽  
Supercritical Co2 ◽  
Velocity Ratio ◽  
Design Procedure ◽  
Expansion Ratio ◽  
Maximum Efficiency ◽  
Design Parameters ◽  
Small Scale ◽  
Preliminary Design ◽  
Line Design

Abstract In recent years, supercritical CO2 (sCO2) Brayton cycles have drawn the attention of researchers due to their high cycle efficiencies, compact turbomachinery, and environmental friendliness. For small-scale cycles, radial inflow turbines (RIT) are the prevailing choice and one of the key components. A mean line design procedure for sCO2 RIT is developed and design space exploration conducted for a 100 kW-class turbine for a low-temperature waste-heat utilization sCO2 Brayton cycle. By varying the two design parameters, specific speed and velocity ratio, different turbine configurations are setup and compared numerically by means of computational fluid dynamics (CFD) simulations. Results are analyzed to conclude on optimum design parameters with regard to turbine efficiency and expansion ratio. Specific speeds between 0.2 and 0.5 are recommended for sCO2 RIT with small though flow (3 kg/s). The higher the velocity ratio, the bigger the turbine expansion ratio. Pairs of optimum design parameters that effectuate maximum efficiency are identified, with smaller velocity ratios prevailing for smaller specific speeds. The turbine simulation results for sCO2 are compared to well-established recommendations for the design of RIT from literature, such as the Balje diagram. It is concluded that for the design of sCO2 RITs, the same principles can be used as for those for air turbines. By achieving total-to-static stage and rotor efficiencies of 84% and 86%, respectively, the developed mean line design procedure has proven to be an effective and easily applicable tool for the preliminary design of small-scale sCO2 RIT.

scholarly journals Analysis of Thermoelectric materials for heating applications in Automobiles

2021 ◽  
Vol 850 (1) ◽  
pp. 012041
Author(s):  
D.S. Hirajith ◽  
G.N. Nihaarikha ◽  
K. Praveen ◽  
M.B. Shyam Kumar
Keyword(s):  
Cloud Point ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Thermoelectric Device ◽  
Small Scale ◽  
Thermoelectric Devices ◽  
Study Materials ◽  
Automobile Engines ◽  
Petroleum Fuels ◽  
Selection Of

Abstract In today’s world with the technological advancements, all that has been considered as slags and waste can be utilized to its maximum therefore attaining sustainability. Thermoelectric devices are now being used in various applications including cooling and heating processes in electronics and automobiles. The choice of materials for these thermoelectric devices are essential in order to determine the parameters such as temperature gradient, thermo emf and total heat dissipated with the help of Seebeck, Peltier and Thomson co-efficients. The elements for the thermoelectric device are arranged by their thermo emf produced in the thermoelectric series. This has been taken into account for the selection of materials for the heating device, analyzed in this article. In certain cold countries, temperature can drop below 10°C, which is very much near its cloud point and pour point of petroleum fuels. Thermoelectric devices will thereby come to use in these places to maintain the temperature above the cloud point of the fuel. This study also focuses on another application of waste heat recovery in automobile engines to produce thermo emf, which can be utilized for small scale electronics in automobiles. In this study, materials are analyzed for the previously mentioned applications.

Micro Gas Turbine Integrated With a Supercritical CO2 Brayton Cycle Turbine: Layout Comparison and Thermodynamic Analysis

2020 ◽  
Author(s):  
Fabrizio Reale ◽  
Raniero Sannino ◽  
Raffaele Tuccillo
Keyword(s):  
Gas Turbine ◽  
Supercritical Co2 ◽  
Waste Heat ◽  
Thermal Power ◽  
Energy Systems ◽  
Working Fluid ◽  
Small Scale ◽  
Brayton Cycle ◽  
Part Load ◽  
Micro Gas Turbine

Abstract In an energetic scenario where both distributed energy systems and smart energy grids gain increasing relevance, the research focus is also on the detection of new solutions to increase overall performance of small-scale energy systems. Waste heat recovery (WHR) can represent a good solution to achieve this goal, due to the possibility of converting residual thermal power in thermal engine exhausts into electrical power. The authors, in a recent study, described the opportunities related to the integration of a micro gas turbine (MGT) with a supercritical CO2 Brayton Cycle (sCO2 GT) turbine. The adoption of Supercritical Carbon Dioxide (sCO2) as working fluid in closed Brayton cycles is an old idea, already studied in the 1960s. Only in recent years this topic returned to be of interest for electric power generation (i.e. solar, nuclear, geothermal energy or coupled with traditional thermoelectric power plants as WHR). In this technical paper the authors analyzed the performance variations of different systems layout based on the integration of a topping MGT with a sCO2 GT as bottoming cycle; the performance maps for both topping and bottoming turbomachinery have been included in the thermodynamic model with the aim of investigating the part load working conditions. The MGT considered is a Turbec T100P and its behavior at part load conditions is also described. The potential and critical aspects related to the integration of the sCO2 GT as bottoming cycle are studied also through a comparison between different layouts, in order to establish the optimal compromise between overall efficiencies and complexity of the energy system. The off-design analysis of the integrated system is addressed to evaluate its response to variable electrical and thermal demands.

scholarly journals REVIEW OF ORGANIC RANKINE CYCLE USED IN SMALL- SCALE APPLICATION

2020 ◽  
Vol 7 (1) ◽  
pp. 52-63
Author(s):  
Ali A. F. Al-Hamadani ◽  
Aya Haitham. A. Kareem
Keyword(s):  
Heat Exchanger ◽  
High Efficiency ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Small Scale ◽  
Heat Sources ◽  
Radial Turbine ◽  
Temperature Method ◽  
Energy From Waste

Organic Rankine cycle an alternative way of generating energy from waste heat, fuel and gases at low-temperature. Method (ORC) proved successful and high efficiency to reduce environmental pollution, fuel consumption and convert low to medium heat sources. The paper will be presenting a review investigation on the organic Rankine cycle(ORC), cycle Background, (ORC) configuration, and selecting of working fluids and experimental studied of expansion apparatuses, which are classified into two type volumetric type such as (expander of rotary vane, scroll, reciprocating piston expander and screw) velocity kind (for example axial and radial turbine). Heat exchanger and expander apparatuses are considered economically expensive parts in (ORC).

Effect of Mixture R600a/R601a on Performance of Radial Turbine for Low Temperature Waste Heat

2017 ◽  
Author(s):  
Zemin Bo ◽  
Zhenkun Sang ◽  
Xiaojing Lv ◽  
Yiwu Weng
Keyword(s):  
Low Temperature ◽  
Output Power ◽  
Waste Heat ◽  
Aerodynamic Performance ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Optimal Composition ◽  
Radial Turbine ◽  
Temperature Heat ◽  
Selection Of

A 150kW organic working fluid radial turbine designed for the low temperature waste heat with temperature of 150 ∼ 200°C using R600a as working fluid was selected. Under the condition of same inlet temperature and rotational speed, the mixture R600a(iso-butane) / R601a(iso-pentane) with different compositions was adopted for the CFD numerical simulation to obtain the aerodynamic performance and the detailed flow of the organic working fluid radial turbine. The results show that the mixture R600a / R601a can broaden the output power range and increase the efficiency of the radial turbine compared with the pure working fluid. The output power of the organic working fluid radial turbine increases from 54.03kW to 129.6kW as the R600a composition increases from 0.1 to 0.9. The optimal composition of R600a / R601a was obtained for relatively higher efficiency of the organic working fluid radial turbine. The results can provide a reference for the selection of working fluid for radial turbine of the low temperature heat source.

scholarly journals Design and CFD Analysis of a Radial-Inflow Turbine for Small Scale ORC Applications

2020 ◽  
Vol 197 ◽  
pp. 11005
Author(s):  
Alessandro Cappiello ◽  
Raffaele Tuccillo
Keyword(s):  
Waste Heat ◽  
Three Dimensional ◽  
Organic Rankine Cycle ◽  
Industrial Process ◽  
Rankine Cycle ◽  
Energy Conversion Efficiency ◽  
Working Fluid ◽  
Energy Sources ◽  
Small Scale ◽  
Line Design

In recent years, Organic Rankine Cycle (ORC) technology has received growing interests, thanks to its high flexibility and to the capability to exploit energy sources at temperature levels difficult to be approached with conventional power cycles. These features allow exploiting renewable and renewable-equivalent energy sources, by either improving the energy conversion efficiency of existing plants or using waste heat from industrial process. As far as the expander is concerned, a high potential solution is represented by turbo-expanders, which allow reduction of plant clutter and complexity, so enhancing the potential impact on the diffusion of small power ORC-based plants. The present work concerns the design of a RadialInflow Turbine for a bottoming Organic Rankine Cycle in the tens of kW scale. Design boundary conditions are retrieved by a zero-dimensional model of a solar-assisted micro gas turbine in cogenerating mode. The design process is started by means of an in-house mean-line design code accounting for real gas properties. The code is used to carry out parametric analyses to investigate the design space for several working fluids encompassing different classes, namely refrigerants and siloxanes. The program is used to assess the effect of design variables and working fluid on the turbine performance and turbine design characteristics. Subsequently, the most promising design candidates are selected and three-dimensional first guess stator and rotor geometries are built on these preliminary designs. Stationary and rotating passages are then meshed and analyzed by means of RANS CFD based solution of the stator – rotor interaction.

scholarly journals Parameterized, numerical design of a two-wheel Curtis steam turbine for small scale WHR

2021 ◽  
Vol 345 ◽  
pp. 00031
Author(s):  
Philipp Streit ◽  
Andreas P. Weiß
Keyword(s):  
Waste Heat ◽  
Negative Impact ◽  
Current Trend ◽  
Design Tool ◽  
Small Scale ◽  
3D Cad ◽  
High Fluid ◽  
Micro Turbine ◽  
Under Construction ◽  
Turbine Design

In contrast to the current trend of converting waste heat into electricity in the small power range below 100 kWel by means of an ORC plant, the authors are pursuing the concept of a micro steam power plant equipped with a micro turbine. Water avoids many of the problems often associated with organic working fluids, such as flammability, toxicity, greenhouse gas effect and high fluid costs. However, water vapor makes turbine design more challenging. The physical reasons for this are repeated, and thereby it becomes clear why a velocity compounded two wheel Curtis turbine has been chosen. The used in-house 1D turbine design tool is briefly introduced. More focus is put on the shortcomings of the implemented 1D loss model and their negative impact on the current turbine design. Consequently, the authors continued actual turbine design by a parameterized approach in 3D CAD/CFD. This approach is explained, and finally, the CFD flow field and the performance maps of the designed turbine are discussed. The turbine is currently under construction and will be installed in 2022 in a waste heat recovery (WHR) plant in Nuremberg/Germany.

scholarly journals Radial Turbine Design for Solar Chimney Power Plants

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 674
Author(s):  
Paul Caicedo ◽  
David Wood ◽  
Craig Johansen
Keyword(s):  
Power Plants ◽  
Reference Frames ◽  
Three Dimensional ◽  
Discrete Ordinates ◽  
Large Area ◽  
Solar Chimney ◽  
Cfd Simulations ◽  
Radial Turbine ◽  
Design Changes ◽  
Turbine Design

Solar chimney power plants (SCPPs) collect air heated over a large area on the ground and exhaust it through a turbine or turbines located near the base of a tall chimney to produce renewable electricity. SCPP design in practice is likely to be specific to the site and of variable size, both of which require a purpose-built turbine. If SCPP turbines cannot be mass produced, unlike wind turbines, for example, they should be as cheap as possible to manufacture as their design changes. It is argued that a radial inflow turbine with blades made from metal sheets, or similar material, is likely to achieve this objective. This turbine type has not previously been considered for SCPPs. This article presents the design of a radial turbine to be placed hypothetically at the bottom of the Manzanares SCPP, the only large prototype to be built. Three-dimensional computational fluid dynamics (CFD) simulations were used to assess the turbine’s performance when installed in the SCPP. Multiple reference frames with the renormalization group k-ε turbulence model, and a discrete ordinates non-gray radiation model were used in the CFD simulations. Three radial turbines were designed and simulated. The largest power output was 77.7 kW at a shaft speed of 15 rpm for a solar radiation of 850 W/m2 which exceeds by more than 40 kW the original axial turbine used in Manzanares. Further, the efficiency of this turbine matches the highest efficiency of competing turbine designs in the literature.

scholarly journals 2D Nanomaterials for Effective Energy Scavenging

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Md Al Mahadi Hasan ◽  
Yuanhao Wang ◽  
Chris R. Bowen ◽  
Ya Yang
Keyword(s):  
Large Scale ◽  
Waste Heat ◽  
Material Selection ◽  
Power Supplies ◽  
Small Scale ◽  
Energy Scavenging ◽  
Power Sources ◽  
Practical Applications ◽  
2D Nanomaterials ◽  
Self Powered

AbstractThe development of a nation is deeply related to its energy consumption. 2D nanomaterials have become a spotlight for energy harvesting applications from the small-scale of low-power electronics to a large-scale for industry-level applications, such as self-powered sensor devices, environmental monitoring, and large-scale power generation. Scientists from around the world are working to utilize their engrossing properties to overcome the challenges in material selection and fabrication technologies for compact energy scavenging devices to replace batteries and traditional power sources. In this review, the variety of techniques for scavenging energies from sustainable sources such as solar, air, waste heat, and surrounding mechanical forces are discussed that exploit the fascinating properties of 2D nanomaterials. In addition, practical applications of these fabricated power generating devices and their performance as an alternative to conventional power supplies are discussed with the future pertinence to solve the energy problems in various fields and applications.

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