scholarly journals Development and Validation of a Thermo-Economic Model for Design Optimisation and Off-Design Performance Evaluation of a Pure Solar Microturbine

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3199 ◽  
Author(s):  
Davide Iaria ◽  
Homam Nipkey ◽  
Jafar Al Zaili ◽  
Abdulnaser Sayma ◽  
Mohsen Assadi
Keyword(s):  
Performance Evaluation ◽  
Economic Model ◽  
Operating Conditions ◽  
Solar Irradiation ◽  
Electricity Production ◽  
Programming Approach ◽  
Cost Of Electricity ◽  
Design Performance ◽  
Wide Range

The aim of this paper is to present a thermo-economic model of a microturbine for solar dish applications, which demonstrates the applicability and accuracy of the model for off-design performance evaluation and techno-economic optimisation purposes. The model is built using an object-oriented programming approach. Each component is represented using a class made of functions that perform a one-dimensional physical design, off-design performance analysis and the component cost evaluation. Compressor, recuperator, receiver and turbine models are presented and validated against experimental data available in literature, and each demonstrated good accuracy for a wide range of operating conditions. A 7-kWe microturbine and solar irradiation data available for Rome between 2004 and 2005 were considered as a case study, and the thermo-economic analysis of the plant was performed to estimate the levelised cost of electricity based on the annual performance of the plant. The overall energy produced by the plant is 10,682 kWh, the capital cost has been estimated to be EUR 27,051 and, consequently, the specific cost of the plant, defined as the ratio between the cost of components and output power in design condition, has been estimated to be around EUR 3980/kWe. Results from the levelised cost of electricity (LCOE) analysis demonstrate a levelised cost of electricity of EUR 22.81/kWh considering a plant lifetime of 25 years. The results of the present case study have been compared with the results from IPSEpro 7 where the same component characteristic maps and operational strategy were considered. This comparison was aimed to verify the component matching procedure adopted for the present model. A plant sizing optimisation was then performed to determine the plant size which minimises the levelised cost of electricity. The design space of the optimisation variable is limited to the values 0.07–0.16 kg/s. Results of the optimisation demonstrate a minimum LCOE of 21.5 [EUR/kWh] for a design point mass flow rate of about 0.11 kg/s. This corresponds to an overall cost of the plant of around EUR 32,600, with a dish diameter of 9.4 m and an annual electricity production of 13,700 [kWh].

Analysis of the Rotordynamic Response of a Centrifugal Compressor Subject to Aerodynamic Loads due to Rotating Stall

2014 ◽  
Author(s):  
Davide Biliotti ◽  
Alessandro Bianchini ◽  
Giuseppe Vannini ◽  
Elisabetta Belardini ◽  
Marco Giachi ◽  
...  
Keyword(s):  
Excitation Frequency ◽  
Load Condition ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Range Analysis ◽  
Radial Vibrations ◽  
Aerodynamic Loads ◽  
Flow Limit ◽  
Wide Range

In the current industrial research on centrifugal compressors, manufacturers are showing increasing interest in the extension of the minimum stable flow limit in order to improve the operability of each unit. The aerodynamic performance of a compressor stage is indeed often limited before surge by the occurrence of diffuser rotating stall. This phenomenon generally causes an increase of the radial vibrations, which, however, is not always connected with a remarkable performance detriment. In case the operating curve has been limited by a mechanical criterion, i.e. based on the onset of induced vibrations, an investigation on the evolution of the aerodynamic phenomenon when the flow rate is further reduced can provide some useful information. In particular, the identification of the real thermodynamic limit of the system could allow one to verify if the new load condition could be tolerated by the rotordynamic system in terms of radial vibrations. Within this context, recent works showed that the aerodynamic loads due to a vaneless diffuser rotating stall can be estimated by means of test-rig experimental data of the most critical stage. Moreover, by including these data into a rotordynamic model of the whole machine, the expected vibration levels in real operating conditions can be satisfactorily predicted. To this purpose, a wide-range analysis was carried out on a large industrial database of impellers operating in presence of diffuser rotating stall; the analysis highlighted specific ranges for the resultant rotating force in terms of intensity and excitation frequency. Moving from these results, rotordynamic analyses have been performed on a specific case study to assess the final impact of these aerodynamic excitations.

The Off-Design Performance of a Low-Pressure Turbine Cascade

1987 ◽  
Vol 109 (2) ◽  
pp. 201-209 ◽  
Author(s):  
H. P. Hodson ◽  
R. G. Dominy
Keyword(s):  
Reynolds Numbers ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Surface Flow ◽  
Operating Conditions ◽  
Turbine Cascade ◽  
Linear Cascade ◽  
Design Performance ◽  
Low Pressure Turbine ◽  
Wide Range

The ability of a given blade profile to operate over a wide range of conditions is often of the utmost importance. This paper reports the off-design performance of a low-pressure turbine rotor root section in a linear cascade. Data were obtained using pneumatic probes and surface flow visualization. The effects of incidence (+9, 0, −20 deg), Reynolds (1.5, 2.9, 6.0 × 105), pitch-chord ratio (0.46, 0.56, 0.69), and inlet boundary layer thickness (0.011, 0.022 δ*/C) are discussed. Particular attention is paid to the three dimensionality of the flow field. Significant differences in the detail of the flow occur over the range of operating conditions investigated. It is found that the production of new secondary loss is greatest at lower Reynolds numbers, positive incidence, and the higher pitch-chord ratios.

Analysis of the Rotordynamic Response of a Centrifugal Compressor Subject to Aerodynamic Loads Due to Rotating Stall

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Davide Biliotti ◽  
Alessandro Bianchini ◽  
Giuseppe Vannini ◽  
Elisabetta Belardini ◽  
Marco Giachi ◽  
...  
Keyword(s):  
Excitation Frequency ◽  
Load Condition ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Range Analysis ◽  
Radial Vibrations ◽  
Aerodynamic Loads ◽  
Flow Limit ◽  
Wide Range

In the current industrial research on centrifugal compressors, manufacturers are showing increasing interest in the extension of the minimum stable flow limit in order to improve the operability of each unit. The aerodynamic performance of a compressor stage is indeed often limited before surge by the occurrence of diffuser rotating stall. This phenomenon generally causes an increase of the radial vibrations, which, however, is not always connected with a remarkable performance detriment. In case the operating curve has been limited by a mechanical criterion, i.e., based on the onset of induced vibrations, an investigation on the evolution of the aerodynamic phenomenon when the flow rate is further reduced can provide some useful information. In particular, the identification of the real thermodynamic limit of the system could allow one to verify if the new load condition could be tolerated by the rotordynamic system in terms of radial vibrations. Within this context, recent works showed that the aerodynamic loads due to a vaneless diffuser rotating stall can be estimated by means of test-rig experimental data of the most critical stage. Moreover, by including these data into a rotordynamic model of the whole machine, the expected vibration levels in real operating conditions can be satisfactorily predicted. To this purpose, a wide-range analysis was carried out on a large industrial database of impellers operating in presence of diffuser rotating stall; the analysis highlighted specific ranges for the resultant rotating force in terms of intensity and excitation frequency. Moving from these results, rotordynamic analyses have been performed on a specific case study to assess the final impact of these aerodynamic excitations.

scholarly journals Evaluating the Use of Leaned Stator Vanes to Produce a Non-Uniform Flow Distribution Across the Inlet Span of a Mixed Flow Turbine Rotor

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Richard Morrison ◽  
Stephen Spence ◽  
Sung In Kim ◽  
Thomas Leonard ◽  
Andre Starke
Keyword(s):  
Leading Edge ◽  
Operating Conditions ◽  
Operating Point ◽  
Mixed Flow ◽  
Design Performance ◽  
Turbine Performance ◽  
Percentage Points ◽  
Wide Range ◽  
Turbine Rotors ◽  
Operating Points

Abstract Current trends in the automotive industry have placed an increased emphasis on downsized turbocharged engines for passenger vehicles. The turbocharger is increasingly relied upon to improve power output across a wide range of engine operating conditions, placing a greater emphasis on turbocharger off-design performance. An off-design condition of significant importance is performance at low turbine velocity ratios, since it is relevant to engine transient response and also to efficient energy extraction from pressure pulses in the unsteady exhaust flow. An increased focus has been placed on equipping turbochargers with mixed flow turbine rotors instead of conventional radial flow turbine rotors to improve off-design performance and to reduce rotor inertia. A recognized feature of a mixed flow turbine is the spanwise variation of flow conditions across the blade leading edge. This is a consequence of the reduction in leading edge radius from shroud to hub, coupled with the increasing tangential velocity of the flow due to conserved angular momentum as the radius decreases. The result is increasingly positive incidence toward the hub side of the leading edge. The resulting region of highly positive incidence at the hub produces separation from the suction surface and generates significant loss within the rotor passage. The aim of this study was to determine if the losses in a mixed flow turbine (MFT) could be reduced by the use of leaned stator vanes, which deliberately created a significant spanwise variation of flow angle between hub and shroud at rotor inlet, to reduce the positive incidence at the hub. The turbine performance with a series of leaned vanes was compared against that of a straight vane using a validated computational fluid dynamics (CFD) model. It was found that increasing vane lean improved turbine performance at all operating points considered. An increase of 3.2 percentage points in stage total-to-static efficiency was achieved at a key off-design operating point. Experimental testing of a set of leaned vanes and the baseline vanes confirmed the advantage of the leaned vanes at all operating points, with an increase in measured efficiency of 2.6 percentage points at the key off-design condition. Unsteady CFD models confirmed the same level of improvement at this operating point. The CFD and experimental results confirmed that the losses in an MFT can be reduced by the use of leaned stator vanes to shape the flow at rotor inlet.

scholarly journals An Introduction to Indoor Localization Techniques. Case of Study: A Multi-Trilateration-Based Localization System with User–Environment Interaction Feature

2021 ◽  
Vol 11 (16) ◽  
pp. 7392
Author(s):  
Bruno Andò ◽  
Salvatore Baglio ◽  
Ruben Crispino ◽  
Vincenzo Marletta
Keyword(s):  
System Architecture ◽  
Indoor Localization ◽  
State Of The Art ◽  
Operating Conditions ◽  
Environment Interaction ◽  
End User ◽  
Localization System ◽  
Wide Range ◽  
Continuous Estimation

The problem of estimating the indoor position of a person or an object, also known as indoor localization, has gained a lot of interest in the last decades. Actually, this feature would be valuable in many application contexts, from logistics to robotic and Assistive Technology. Different solutions have been proposed in the literature, exploiting a wide range of approaches. This paper aims to provide a brief review of the state-of-the-art approaches in the field, as well as to present the RESIMA case study. The latter exploits an ultrasound-based indoor localization system and a User–Environment Interaction functionality, which allows for performing the continuous estimation of the distance between the end-user and objects in the environment. The latter is valuable to provide the end-user with efficient assistance during the environment exploitation. The main focus of this work is related to the overall description of the system architecture, the trilateration algorithm adopted for the sake of user localization and the estimation of the delay time produced by user-distance computation under different operating conditions.

Axial Turbine Performance Evaluation. Part A—Loss-Geometry Relationships

1968 ◽  
Vol 90 (4) ◽  
pp. 341-348 ◽  
Author(s):  
O. E. Balje´ ◽  
R. L. Binsley
Keyword(s):  
Reynolds Number ◽  
Performance Evaluation ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Published Data ◽  
Blade Height ◽  
Blade Number ◽  
Turbine Performance ◽  
Wide Range ◽  
Partial Admission

Generalized loss correlations for full and partial admission turbines have been derived and critically compared with recently published data. Effects included are Reynolds number, blade angles, blade height, blade number, blade trailing edge thickness, tip clearance, and reaction. These generalized loss relationships are for use in optimization of turbines over a wide range of possible operating conditions.

Modeling and Analysis of the Performance of a Parabolic Trough Solar Concentrator System

2013 ◽  
Author(s):  
M. Hammad ◽  
A. Al-Qtiemat ◽  
A. Alshqirate
Keyword(s):  
Large Scale ◽  
Thermal Power ◽  
Boiling Water ◽  
Plant Production ◽  
Solar Irradiation ◽  
Electricity Production ◽  
Solar Concentrator ◽  
Parabolic Trough ◽  
Pressurized Water

The increasing fossil fuel costs have led the world to use the clean and naturally available energy from the sun to produce electric power. Parabolic trough technology is nowadays the most extended solar system for electricity production or steam generation for industrial processes. It is the most proven, lowest cost and large-scale solar power technology available today. It is basically composed of a concentrator collector field which converts solar irradiation into thermal energy that will be used as input for a Rankine power cycle. In such plants, a storage system can be implemented in order to increase plant production. This work aimed to conclude with a simulation model of a solar thermal power plant using a parabol solar concentrator. The Euro Trough (ET) Concentrator was used as case study. MATLAB software was used for the analysis and performance evaluation. Different working fluids were used in the simulation which were: Pressurized water, Boiling water and Oil (Therminol-VP1). It was found that using water (pressurized or boiling) in the receiver tube is better than the Therminol-VP1 oil. And the pressurized water has the highest value of efficiency compared to the boiling water and Therminol-VP1 oil. The oil using system presented the highest energy losses system, and the lowest efficiencies. The ET performance was tested at different places in Jordan, and the distribution of direct solar irradiance at different days around the year was calculate and exhibited for Ma’an city as a case study. A comparison between simulated results and that found in literature were carried out with observed good conformity.

scholarly journals The Off-Design Performance of a Low Pressure Turbine Cascade

1986 ◽  
Author(s):  
H. P. Hodson ◽  
R. G. Dominy
Keyword(s):  
Reynolds Numbers ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Surface Flow ◽  
Operating Conditions ◽  
Flow Visualisation ◽  
Turbine Cascade ◽  
Design Performance ◽  
Low Pressure Turbine ◽  
Wide Range

The ability of a given blade profile to operate over a wide range of conditions is often of the utmost importance. This paper reports the off-design performance of a low pressure turbine rotor root section in a linear cascade. Data were obtained using pneumatic probes and surface flow visualisation. The effects of incidence (+9, 0, −20 deg.), Reynolds No. (1.5, 2.9, 6.0×105), pitch-chord ratio (0.46, 0.56, 0.69) and inlet boundary layer thickness (0.011, 0.022 δ*/C) are discussed. Particular attention is paid to the three-dimensionality of the flow field. Significant differences in the detail of the flow occur over the range of operating conditions investigated. It is found that the production of new secondary loss is greatest at the lower Reynolds numbers, positive incidence and the higher pitch-chord ratios.

Reliability Evaluation of Electronic Devices Under Considering the Actual Use Conditions

2011 ◽  
Author(s):  
Shilin Liu ◽  
Qiang Yu ◽  
Michael Pecht
Keyword(s):  
Individual Component ◽  
Electronic Devices ◽  
Operating Conditions ◽  
Product Configuration ◽  
Component Reliability ◽  
Wide Range ◽  
Close Proximity ◽  
Actual Use ◽  
End Use

Semiconductor component manufacturers supply to different product manufacturers in a wide range of market segments, for different end use applications. The goal of electronic component qualification is to demonstrate component reliability under operating conditions in the end product configuration. While a manufacturer may have successfully qualified an individual component, operating stresses due to surrounding components or the system can decrease individual component reliability. Not accounting for these operating stresses resulting from other components or the system will lead to lower life than anticipated. Using a case study, the authors demonstrate how the fatigue life of a chip component mounted on a PCB is affected by powered components on the board in close proximity.

scholarly journals Quasi-Z-Source Four-Leg Inverter with PV by using Model Predictive Control Scheme

2019 ◽  
pp. 73-82
Author(s):  
Konda Ramanaiah ◽  
P. Rajasekhar
Keyword(s):  
Renewable Energy ◽  
Model Predictive Control ◽  
Predictive Control ◽  
Renewable Energy Sources ◽  
Operating Conditions ◽  
Solar Irradiation ◽  
Voltage Source ◽  
Three Phase ◽  
Control Scheme ◽  
Wide Range

The Implementation of Quasi-Z-Source Four-Leg Inverter with PV by using Model Predictive Control Scheme is proposed in this paper. In order to reduce the drawbacks of traditional three phase voltage source inverter (VSI). Photovoltaic (PV) is a term which converts the light into electricity. This topology features a wide range of voltage gain which is suitable for applications in renewable energy-based power systems, where the output of the renewable energy sources varies widely with operating conditions such as wind speed, solar irradiation and temperature. To improve the capability of the controller, an MPC scheme is used which implements a discrete-time model of the system. The controller handles each phase current independently, which adds flexibility to the system. The performance of quasi z source three-phase four-leg VSI with PV by using model predictive control (MPC) was simulated using MATLAB Simulink under balanced and unbalanced load conditions as well as single-phase open-circuit fault condition.

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