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.

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.

scholarly journals Performance Evaluation of a Small Scale Modular Solar Trigeneration System

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Handong Wang
Keyword(s):  
Vapor Pressure ◽  
Thermal Power ◽  
Hot Water ◽  
Solar Thermal ◽  
Modular System ◽  
Small Scale ◽  
Inlet Temperature ◽  
Increase With Increase ◽  
Energy And Exergy ◽  
System Operating

In order to improve the efficiency of solar thermal power (STP) system, a novel modular system combining cooling, heating, and power generation (CCHP) is proposed and introduced in this work. This modular CCHP system can simultaneously provide 10 kW electricity, −15~5°C coolant, and 60°C hot water to meet the requirements of cooling, heating, and electricity in a general family or other fields. The flow chart and working process of the modular system are introduced, based on which the energy and exergy efficiencies at the CCHP and STP operation modes are primarily evaluated and discussed. The results show that when the output electricity is constant, the overall efficiencies of energy and exergy of the system operating at the CCHP mode are 9.37 times and 2.62 times as big as those of the system operating at the STP mode, respectively. Thus, the modular solar thermal CCHP system can improve the energy and exergy efficiencies. Furthermore, calculation shows that both the overall energy and exergy efficiencies decrease with increase of inlet vapor temperature at given inlet vapor pressure, but both the efficiencies increase with increase of inlet vapor pressure at given inlet temperature.

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.

A methodology to identify potential markets for small-scale solar thermal power generators

2016 ◽  
Vol 169 ◽  
pp. 287-300 ◽  
Author(s):  
David Sánchez ◽  
Anna Bortkiewicz ◽  
José M. Rodríguez ◽  
Gonzalo S. Martínez ◽  
Giacomo Gavagnin ◽  
...  
Keyword(s):  
Thermal Power ◽  
Solar Thermal ◽  
Small Scale ◽  
Power Generators ◽  
Solar Thermal Power

scholarly journals Dynamic Modeling and Preliminary Performance Analysis of a New Solar Thermal Reverse Osmosis Desalination Process

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 4015 ◽  
Author(s):  
Clément Lacroix ◽  
Maxime Perier-Muzet ◽  
Driss Stitou
Keyword(s):  
Energy Consumption ◽  
Reverse Osmosis ◽  
Dynamic Modeling ◽  
Thermal Energy ◽  
Thermal Power ◽  
Solar Thermal ◽  
Working Fluid ◽  
Small Scale ◽  
Low Grade ◽  
Solar Collectors

Reverse osmosis (RO) is a desalination technique that is commonly preferred because of its low energy consumption. In this paper, an innovative, thermally powered RO desalination process is presented. This new thermo-hydraulic process uses solar thermal energy in order to realize the pressurization of the saltwater beyond its osmotic pressure to allow its desalination. This pressurization is enabled thanks to a piston or a membrane set in motion in a reservoir by a working fluid that follows a thermodynamic cycle similar to an Organic Rankine Cycle. In this cycle, the evaporator is heated by low-grade heat, such as the one delivered by flat-plate solar collectors, while the condenser is cooled by the saltwater to be treated. Such an installation, designed for small-scale (1 to 10 m3·day−1) brackish water desalination, should enable an average daily production of 500 L of drinkable water per m² of solar collectors with a specific thermal energy consumption of about 6 kWhth·m−3. A dynamic modeling of the whole process has been developed in order to study its dynamic cyclic operating behavior under variable solar thermal power, to optimize its design, and to maximize its performances. This paper presents the preliminary performance results of such a solar-driven desalination process.

Design of a 200 kWe Solar Thermal Power Plant for Ontario

2008 ◽  
Author(s):  
Thomas A. Cooper ◽  
James S. Wallace
Keyword(s):  
Power Plant ◽  
Thermal Power Plant ◽  
Solar Collector ◽  
Thermal Power ◽  
Solar Thermal ◽  
Working Fluid ◽  
Small Scale ◽  
Computer Simulation Model ◽  
Night Time ◽  
Solar Thermal Power

A preliminary design and feasibility study has been conducted for a 200 kWe solar thermal power plant for operation in Ontario. The objective of this study is to assess the feasibility of small-scale commercial solar thermal power production in areas of relatively low insolation. The design has been developed for a convention centre site in Toronto, Ontario. The plant utilizes a portion of the large flat roof area of the convention centre to accommodate the collector array. Each power plant module provides a constant electrical output of 200 kWe throughout the year. The system is capable of maintaining the constant output during periods of low insolation, including night-time hours and cloudy periods, through a combination of thermal storage and a supplemental natural gas heat source. The powerplant utilized the organic Ranking cycle (ORC) to allow for relatively low source temperatures from the solar collector array. A computer simulation model was developed to determine the performance of the system year-round using the utilizability-solar fraction method. The ORC powerplant uses R245fa as the working fluid and operates at an overall efficiency of 11.1%. The collector is a non-concentrating evacuated tube type and operates at a temperature of 90°C with an average annual efficiency of 23.9%. The system is capable of achieving annual solar fractions of 0.686 to 0.874 with collector array areas ranging from 30 000 to 40 000 m2 and storage tank sizes ranging from 3.8 to 10 × 106L respectively. The lowest possible cost of producing electricity from the system is $0.393 CAD/kWh. The results of the study suggest that small-scale solar thermal plants are physically viable for year round operation in Ontario. The proposed system may be economically feasible given Ontario’s fixed purchase price of $0.42 CAD/kWh, but the cost of producing electricity from the system is highly dependent on the price of the solar collector.

scholarly journals Design and Optimization of a Radial Turbine to Be Used in a Rankine Cycle Operating with an OTEC System

2020 ◽  
Vol 8 (11) ◽  
pp. 855
Author(s):  
Khaled Alawadhi ◽  
Yousef Alhouli ◽  
Ali Ashour ◽  
Abdullah Alfalah
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Optimization Procedure ◽  
Rankine Cycle ◽  
Turbine Rotor ◽  
Design Code ◽  
Design And Optimization ◽  
Radial Turbine ◽  
Turbine Design ◽  
Base Design

Design and optimization of a radial turbine for a Rankine cycle were accomplished ensuring higher thermal efficiency of the system despite the low turbine inlet temperature. A turbine design code (TDC) based on the meanline design methodology was developed to construct the base design of the turbine rotor. Best design practices for the base design were discussed and adopted to initiate a robust optimization procedure. The baseline design was optimized using the response surface methodology and by coupling it with the genetic algorithm. The design variables considered for the study are rotational speed, total to static speed ratio, hub radius ratio, shroud radius ration, and number of blades. Various designs of the turbine were constructed based on the Central Composite Design (CCD) while performance variables were computed using the in-house turbine design code (TDC) in the MATLAB environment. The TDC can access the properties of the working fluid through a subroutine that links NIST’s REFPROP to the design code through a subroutine. The finalization of the geometry was made through an iterative process between 3D-Reynolds-Averaged Navier-Stokes (RANS) simulations and the one-dimensional optimization procedure. 3D RANS simulations were also conducted to analyze the optimized geometry of the turbine rotor for off-design conditions. For computational fluid dynamics (CFD) simulation, a commercial code ANSYS-CFX was employed. 3D geometry was constructed using ASYS Bladegen while structured mesh was generated using ANSYS Turbogrid. Fluid properties were supplied to the CFD solver through a real gas property (RGP) file that was constructed in MATLAB by linking it to REFPROP. Computed results show that an initial good design can reduce the time and computational efforts necessary to reach an optimal design successfully. Furthermore, it can be inferred from the CFD calculation that Response Surface Methodology (RSM) employing CFD as a model evaluation tool can be highly effective for the design and optimization of turbomachinery.

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