scholarly journals Comprehensive Analysis with Enhanced Resolution of HAWT Blade using CFD

2021 ◽  
Vol 18 (17) ◽  
Author(s):  
Amjith Lilly RAVEENDRAN ◽  
Bavanish BALA
Keyword(s):  
Wind Energy ◽  
Wind Turbines ◽  
Power Output ◽  
Fossil Fuels ◽  
Turbine Blades ◽  
Electrical Power ◽  
Blade Angle ◽  
Power Sources ◽  
Wind Velocities ◽  
Electrical Power Output

Energy is an important aspect for all countries. Due to the overexploitation of resources, nonrenewable resources, such as fossil fuels, are depleting day by day. This calls for alternative power sources, such as wind energy. Wind energy is a clean and inexhaustible source of energy. One of the ways of harvesting this energy is using wind turbines, which transform the kinetic energy of wind into electrical power output. Wind turbines face many problems, such as low wind hours, design issues, and so on. The main focus of this work is to find the optimum blade angle of turbine blades, in order to produce the maximum power output, even at low wind hours. In this study, CFD analysis is done on a 5 MW wind turbine blade at wind velocities 3, 12.5 and 25 m/s, which are the cut in, rated, and cut out velocities of wind turbines, respectively. The range of angles under consideration varies from 20 to 89 °. A 3D model of the blade is analyzed using ANSYS Fluent 19.0. The optimum blade angle is identified, and the characteristics of the curves of blade angles, with respect to different parameters, are obtained. HIGHLIGHTS Optimum Blade angle for better moment Pressure and velocity Characteristics at various blade angles 5MW HAWT blade moments for wind velocity of 3,12.5 and 25 m/s The maximum moment is obtained at an angle 82 degree at various wind velocities GRAPHICAL ABSTRACT

Performance Analysis of Near-Field Thermophotovoltaic With a Multilayer Metallodielectric Emitter

2016 ◽  
Author(s):  
Y. Yang ◽  
J. Y. Chang ◽  
L. P. Wang
Keyword(s):  
Heat Flux ◽  
Power Output ◽  
Indium Tin Oxide ◽  
Effective Medium Theory ◽  
Near Field ◽  
Electrical Power ◽  
Electrical Contacts ◽  
Alumina Layer ◽  
Photon Transport ◽  
Electrical Power Output

The photon transport and energy conversion of a near-field thermophotovoltaic (TPV) system with a selective emitter composed of alternate tungsten and alumina layers and a photovoltaic cell sandwiched by electrical contacts are theoretically investigated in this paper. Fluctuational electrodynamics along with the dyadic Green’s function for a multilayered structure is applied to calculate the spectral heat flux, and photocurrent generation and electrical power output are solved from the photon-coupled charge transport equations. The tungsten and alumina layer thicknesses are optimized to match the spectral heat flux with the bandgap of TPV cell. The spectral heat flux is much enhanced when plain tungsten emitter is replaced with the multilayer emitter due to the mechanism of surface plasmon polariton coupling in the tungsten thin film. In addition, the invalidity of effective medium theory to predict photon transport in the near field with multilayer emitters is discussed. Effects of a gold back reflector and indium tin oxide front coating with nanometer thickness, which could practically act as the electrodes to collect the photon-generated charges on the TPV cell, are explored. Conversion efficiency of 23.7% and electrical power output of 0.31 MW/m2 are achieved at 100 nm vacuum gap when the emitter and receiver are respectively at temperatures of 2000 K and 300 K.

scholarly journals Evaluating Energy Generation Capacity of PVDF Sensors: Effects of Sensor Geometry and Loading

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1895
Author(s):  
Mohammad Uddin ◽  
Shane Alford ◽  
Syed Mahfuzul Aziz
Keyword(s):  
Surface Area ◽  
Power Output ◽  
Energy Harvester ◽  
Mechanical Strain ◽  
Electrical Power ◽  
Human Movement ◽  
Loading Frequency ◽  
Dielectric Thickness ◽  
Generating Capacity ◽  
Electrical Power Output

This paper focuses on the energy generating capacity of polyvinylidene difluoride (PVDF) piezoelectric material through a number of prototype sensors with different geometric and loading characteristics. The effect of sensor configuration, surface area, dielectric thickness, aspect ratio, loading frequency and strain on electrical power output was investigated systematically. Results showed that parallel bimorph sensor was found to be the best energy harvester, with measured capacitance being reasonably acceptable. Power output increased with the increase of sensor’s surface area, loading frequency, and mechanical strain, but decreased with the increase of the sensor thickness. For all scenarios, sensors under flicking loading exhibited higher power output than that under bending. A widely used energy harvesting circuit had been utilized successfully to convert the AC signal to DC, but at the sacrifice of some losses in power output. This study provided a useful insight and experimental validation into the optimization process for an energy harvester based on human movement for future development.

Techno-Economic Assessment of Utilizing Wind Energy for Hydrogen Production Through Electrolysis

2017 ◽  
Author(s):  
Reza Ziazi ◽  
Kasra Mohammadi ◽  
Navid Goudarzi
Keyword(s):  
Hydrogen Production ◽  
Wind Energy ◽  
Wind Turbines ◽  
Alternative Energy ◽  
Large Scale ◽  
Fossil Fuels ◽  
Combustion Engine ◽  
Economic Assessment ◽  
Large Cities ◽  
North East

Hydrogen as a clean alternative energy carrier for the future is required to be produced through environmentally friendly approaches. Use of renewables such as wind energy for hydrogen production is an appealing way to securely sustain the worldwide trade energy systems. In this approach, wind turbines provide the electricity required for the electrolysis process to split the water into hydrogen and oxygen. The generated hydrogen can then be stored and utilized later for electricity generation via either a fuel cell or an internal combustion engine that turn a generator. In this study, techno-economic evaluation of hydrogen production by electrolysis using wind power investigated in a windy location, named Binaloud, located in north-east of Iran. Development of different large scale wind turbines with different rated capacity is evaluated in all selected locations. Moreover, different capacities of electrolytic for large scale hydrogen production is evaluated. Hydrogen production through wind energy can reduce the usage of unsustainable, financially unstable, and polluting fossil fuels that are becoming a major issue in large cities of Iran.

Experimental Investigation of a Flat Plate Photovoltaic/Thermal Collector

2018 ◽  
Author(s):  
Mohamad Modrek ◽  
Ali Al-Alili
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Power Output ◽  
Electrical Power ◽  
Solar Thermal ◽  
Pv Panel ◽  
Solar Thermal Collectors ◽  
Electrical Power Output ◽  
Electrical Output

Photovoltaic thermal collectors (PVT) combines technologies of photovoltaic panels and solar thermal collectors into a hybrid system by attaching an absorber to the back surface of a PV panel. PVT collectors have gained a lot of attention recently due to the high energy output per unit area compared to a standalone system of PV panels and solar thermal collectors. In this study, performance of a liquid cooled flat PVT collector under the climatic conditions of Abu Dhabi, United Arab Emirates was experimentally investigated. The electrical performances of the PVT collector was compared to that of a standalone PV panel. Moreover, effect of sand accumulation on performance of PVT collectors was examined. Additionally, effect of mass flow rate on thermal and electrical output of PVT collector was studied. Electrical power output is slightly affected by changes in mass flow rate. However, thermal energy increased by 22% with increasing flow rate. Electrical power output of a PV panel was found to be 38% lower compared to electrical output of PVT collectors. Dust accumulation on PVT surface reduced electrical power output up to 7% compared with a reference PVT collector.

scholarly journals Design of a Hybrid Photovoltaic Thermal System in Lebanon

2018 ◽  
Vol 171 ◽  
pp. 02002
Author(s):  
Elie Karam ◽  
Patrick Moukarzel ◽  
Maya Chamoun ◽  
Charbel Habchi ◽  
Charbel Bou-Mosleh
Keyword(s):  
Power Output ◽  
Electrical Power ◽  
Hot Water ◽  
Thermal System ◽  
Conduction Model ◽  
Electrical Efficiency ◽  
Pv Module ◽  
Temperature Loss ◽  
Photovoltaic Thermal System ◽  
Electrical Power Output

Due to global warming and the high toxic gas emissions of traditional power generation methods, renewable energy has become a very active topic in many applications. This study focuses on one versatile type of solar energy: Hybrid Photovoltaic Thermal System (hybrid PV/T). Hybrid PV/T combines both PV and thermal application and by doing this the efficiency of the system will increase by taking advantage of the temperature loss from PV module. The solar radiation and heat will be harnessed to deliver electricity and hot water simultaneously. In the present study a solar system is designed to recycle the heat and improve the temperature loss from PV module in order to supply both electricity and domestic hot water. The project was tested twice in Zouk Mosbeh - Lebanon; on May 18, 2016, and June 7, 2016. The average electrical efficiency was around 11.5% with an average electrical power output of 174.22 W, while with cooling, the average electrical efficiency reaches 11% with a power output of 200 W. The temperature increases by about 7 degrees Celsius from the inlet. The 1D conduction model is also performed in order to design the hybrid PV/T system.

scholarly journals Wind turbine icing characteristics and icing-induced power losses to utility-scale wind turbines

2021 ◽  
Vol 118 (42) ◽  
pp. e2111461118
Author(s):  
Linyue Gao ◽  
Hui Hu
Keyword(s):  
Wind Turbines ◽  
Power Output ◽  
Turbine Blades ◽  
Digital Camera ◽  
Unmanned Aircraft ◽  
Ice Accretion ◽  
Power Losses ◽  
Field Campaign ◽  
Output Losses ◽  
Utility Scale

A field campaign was carried out to investigate ice accretion features on large turbine blades (50 m in length) and to assess power output losses of utility-scale wind turbines induced by ice accretion. After a 30-h icing incident, a high-resolution digital camera carried by an unmanned aircraft system was used to capture photographs of iced turbine blades. Based on the obtained pictures of the frozen blades, the ice layer thickness accreted along the blades’ leading edges was determined quantitatively. While ice was found to accumulate over whole blade spans, outboard blades had more ice structures, with ice layers reaching up to 0.3 m thick toward the blade tips. With the turbine operating data provided by the turbines’ supervisory control and data acquisition systems, icing-induced power output losses were investigated systematically. Despite the high wind, frozen turbines were discovered to rotate substantially slower and even shut down from time to time, resulting in up to 80% of icing-induced turbine power losses during the icing event. The research presented here is a comprehensive field campaign to characterize ice accretion features on full-scaled turbine blades and systematically analyze detrimental impacts of ice accumulation on the power generation of utility-scale wind turbines. The research findings are very useful in bridging the gaps between fundamental icing physics research carried out in highly idealized laboratory settings and the realistic icing phenomena observed on utility-scale wind turbines operating in harsh natural icing conditions.

Confirmation of a Nonlinear Model Predictive Control Strategy Applied to a Permanent Magnet Linear Generator for Wave-Energy Conversion

2014 ◽  
Author(s):  
Nathan Tom
Keyword(s):  
Predictive Control ◽  
Nonlinear Model ◽  
Power Output ◽  
Electrical Power ◽  
Equation Of Motion ◽  
Nonlinear Model Predictive Control ◽  
Floating Body ◽  
Time Varying ◽  
Irregular Wave ◽  
Electrical Power Output

This paper begins with a brief review of the time-domain equation of motion for a generic floating body. The equation of motion of the floating body was modified to account for the influence of a power-take-off unit (PTO) to predict the hydrodynamic and electromechanical performance of the coupled system. As the damping coefficient is considered the dominant contribution to the PTO reaction force, the optimum non time-varying damping values were first presented for all frequencies, recovering the well-known impedance-matching principle at the coupled resonance frequency. In an effort to further maximize power absorption in both regular and irregular wave environments, nonlinear model predictive control (NMPC) was applied to the model-scale point absorber developed at UC Berkeley. The proposed NMPC strategy requires a PTO unit that could be turned on and off instantaneously, leading, interestingly to electrical sequences where the generator would be inactive for up to 60% of the wave period. In order to validate the effectiveness of this NMPC strategy, an in-house designed permanent magnet linear generator (PMLG) was chosen as the PTO. The time-varying performance of the PMLG was first characterized by dry-bench tests, using mechanical relays to control the electromagnetic conversion process. Following this, the physical set-up was transferred to the wave tank. The on/off sequencing of the PMLG was tested under regular and irregular wave excitation to validate NMPC simulations using control inputs obtained from running the control algorithm offline. Experimental results indicate that successful implementation was achieved and the absorbed power using NMPC was up to 50% greater than the passive system, which utilized no controller. However, after considering the PMLG mechanical-to-electrical conversion efficiency the useful electrical power output was not consistently maximized. To improve output power, a mathematical relation between the efficiency and damping magnitude of the PMLG was inserted in the system model to maximize the electrical power output through continued use of NMPC. Of significance, results from these latter simulations provided a damping time series that was active over a larger portion of the wave period and required the actuation of the applied electrical load connected to the PMLG, rather than a simple on/off type control.

scholarly journals Time-Domain Modeling of Tower Shadow and Wind Shear in Wind Turbines

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Swagata Das ◽  
Neeraj Karnik ◽  
Surya Santoso
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Time Domain ◽  
Wind Shear ◽  
Electrical Power ◽  
Rotational Frequency ◽  
Domain Modeling ◽  
Periodic Fluctuations ◽  
Electrical Power Output ◽  
Tower Shadow

Tower shadow and wind shear contribute to periodic fluctuations in electrical power output of a wind turbine generator. The frequency of the periodic fluctuations is times the blade rotational frequency , where is the number of blades. For three-bladed wind turbines, this inherent characteristic is known as the effect. In a weak-power system, it results in voltage fluctuation or flicker at the point of common coupling of the wind turbine to the grid. The phenomenon is important to model so as to evaluate the flicker magnitude at the design level. Hence, the paper aims to develop a detailed time-domain upwind fixed speed wind turbine model which includes the turbine's aerodynamic, mechanical, electrical, as well as tower shadow and wind shear components. The model allows users to input factors such as terrain, tower height, and tower diameter to calculate the oscillations. The model can be expanded to suit studies involving variable speed wind turbines. Six case studies demonstrate how the model can be used for studying wind turbine interconnection and voltage flicker analysis. Results indicate that the model performs as expected.

Dynamic Optimization of Drivetrain Gear Ratio to Maximize Wind Turbine Power Generation—Part 2: Control Design

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
John F. Hall ◽  
Dongmei Chen
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Electrical Power ◽  
Control Design ◽  
Gear Ratio ◽  
Small Wind Turbines ◽  
Full Load Operation ◽  
Wind Profiles ◽  
Turbine Model

The cost of electrical power produced by small wind turbines impedes the use of this technology, which can otherwise provide power to millions of homes in rural regions worldwide. To encourage their use, small wind turbines must capture wind energy more effectively while avoiding increased equipment costs. A variable ratio gearbox (VRG) can provide this capability to the simple fixed-speed wind turbine through discrete operating speeds. This is the second of a two-part publication that focuses on the control of a VRG-enabled wind turbine. The first part presented a 100 kW fixed speed, wind turbine model, and a method for manipulating the VRG and mechanical brake to achieve full load operation. In this study, an optimal control algorithm is developed to maximize the power production in light of the limited brake pad life. Recorded wind data are used to develop a customized control design that is specific to a given site. Three decision-making modules interact with the wind turbine model developed in Part 1 to create possible VRG gear ratio (GR) combinations. Dynamic programming is applied to select the optimal combination and establish the operating protocol. The technique is performed on 20 different wind profiles. The results suggest an increase in wind energy production of nearly 10%.

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