scholarly journals An experimental investigation into a novel small-scale device for energy harvesting using vortex-induced vibration

Author(s):  
Farshad Moradi Gharghani ◽  
Mohamad Ali Bijarchi ◽  
Omid Mohammadi ◽  
Mohammad Behshad Shafii

Abstract Renewable energies could be a good solution to the problems associated with fossil fuels. The storage of wind energy by means of small-scale devices rather than large-scale turbines is a topic that has gained lots of interest. In this study, a compact device is proposed to harvest wind energy and transform it into electrical energy, by means of oscillations of a magnet into a coil, using the concept of vortex-induced vibration (VIV) behind a barrier. For a more comprehensive investigation, this system is studied from two viewpoints of fluid mechanics (without magnet) and power generation (with the magnet). For this purpose, an oscillating plate hinging on one side and three barriers with different geometrical shapes including cylindrical, triangular and rectangular barriers are used. In addition to the effect of barrier geometry, the impacts of various barriers dimensions, the distance between the plate and the barriers as well as inclination angle of the plate with respect to the horizon on the amplitude of oscillations and generated power are investigated. Results showed that in each case, there is a unique Reynolds number in which the frequency of vortex shedding equals to the frequency of plate oscillation and the output power from the energy harvester device is maximum. Besides, by increasing the barrier dimensions, the amplitude of oscillations increases up to three times, which leads to a higher generated power. Finally, by considering the studied parameters, the best conditions for generating energy using the VIV method are presented for design purposes. Among all the considered cases, the cylindrical barrier with the highest diameter and nearest distance to the plate led to the highest efficiency (0.21%) in comparison with other barriers.

2021 ◽  
pp. 0958305X2110193
Author(s):  
Tuyet Thi Anh Nguyen ◽  
Shuo-Yan Chou

Renewable energy has been actively researched and developed in many countries to replace the conventional energy resources that come from fossil fuels. As social and environmental awareness of the renewable energy has grown, it is essential to address both quantitative factors and qualitative factors in determination of the optimal renewable energy portfolio. This paper proposes a novel approach to integrate a financial model and a fuzzy model to analyze both quantitative and qualitative factors. The financial model is utilized to calculate the quantitative factors, thereby assisting experts make judgments more accurately in the fuzzy model. The fuzzy model is utilized to evaluate the qualitative factors based on the expert judgements. Moreover, this paper proposes multi-segment judgment model that analyzes the evaluation of different groups, including government, investor and user groups. The results show that each group has different priority order. For example, the highest-priority factor of Government, Investor and User is environmental (with a score of 0.665), economic (with a score of 0.854), and technological criteria (with a score of 0.771), respectively. The results also indicated that small-scale onshore wind energy, large-scale onshore wind energy and solar energy is the best option for Government, Investor and User, respectively.


Author(s):  
Reza Ziazi ◽  
Kasra Mohammadi ◽  
Navid Goudarzi

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.


2017 ◽  
Vol 8 (3) ◽  
pp. 206-211
Author(s):  
Thi Mai Thao Pham

To evaluate CO2 emission mitigation potential and cost effectiveness of rice husk utilization, Life Cycle Analysis was conducted for 9 scenarios. The results showed that, gasification is the most efficient CO2 mitigation. From cost analysis, the cost mitigation can be achieved by replacing the current fossil fuels in cooking scenarios. Among the power generation scenarios, it was found that 30MW combustion and 5MW gasification power generations were the most economically-efficient scenarios. The briquette combustion power generation appeared less cost-competitive than direct combustion, whilst the large-scale gasification scenarios and the pyrolysis scenarios give the increase in cost from the baseline. From the viewpoints of both CO2 and cost, it was indicated that the win-win scenarios can be the rice husk use for cooking, for large-scale combustion power generation, and for small-scale gasification. Để đánh giá tiềm năng giảm thiểu phát thải CO2 và hiệu quả chi phí của việc sử dụng trấu, phương pháp đánh giá vòng đời sản phẩm đã được thực hiện cho 9 kịch bản. Kết quả cho thấy, khí hóa trấu để sản xuất điện có tiềm năng giảm phát sinh khí CO2 nhiều nhất. Kết quả phân tích chi phí cho thấy việc giảm thiểu chi phí có thể đạt được khi thay thế sử dụng nhiên liệu hóa thạch trong kịch bản dùng trấu cho nấu ăn. Giữa các kịch bản về sản xuất điện, hiệu quả kinh tế cao nhất trong trường hợp đốt trực tiếp trấu để sản xuất điện ở quy mô công xuất lớn (30MW) và khí hóa ở quy mô trung bình (5MW). Trường hợp dùng củi trấu không mang lại hiệu quả kinh tế so với dùng trực tiếp trấu để phát điện. Hai trường hợp dùng trấu để sản xuất dầu sinh học và khí hóa gas công suất lớn (30MW) cho thấy chi phí tăng cao so với điều kiện biên. Kịch bản cho kết quả khả thi về hiệu quả kinh tế và giảm phát thải CO2 là dùng trấu để nấu ăn, đốt trực tiếp để phát điện công suất lớn và khí hóa công suất trung bình.


2001 ◽  
Vol 123 (2) ◽  
pp. 160-163 ◽  
Author(s):  
Rainer Tamme ◽  
Reiner Buck ◽  
Michael Epstein ◽  
Uriyel Fisher ◽  
Chemi Sugarmen

This paper presents a novel process comprising solar upgrading of hydrocarbons by steam reforming in solar specific receiver-reactors and utilizing the upgraded, hydrogen-rich fuel in high efficiency conversion systems, such as gas turbines or fuel cells. In comparison to conventionally heated processes about 30% of fuel can be saved with respect to the same specific output. Such processes can be used in small scale as a stand-alone system for off-grid markets as well as in large scale to be operated in connection with conventional combined-cycle plants. The complete reforming process will be demonstrated in the SOLASYS project, supported by the European Commission in the JOULE/THERMIE framework. The project has been started in June 1998. The SOLASYS plant is designed for 300 kWel output, it consists of the solar field, the solar reformer and a gas turbine, adjusted to operate with the reformed gas. The SOLASYS plant will be operated at the experimental solar test facility of the Weizmann Institute of Science in Israel. Start-up of the pilot plant is scheduled in April 2001. The midterm goal is to replace fossil fuels by renewable or non-conventional feedstock in order to increase the share of renewable energy and to establish processes with only minor or no CO2 emission. Examples might be upgrading of bio-gas from municipal solid waste as well as upgrading of weak gas resources.


Author(s):  
Praveen Laws ◽  
Rajagopal V Bethi ◽  
Pankaj Kumar ◽  
Santanu Mitra

Nonrenewable fossil fuels are finite resources that will ultimately deplete in near future. Nature sheds colossal amount of renewable wind energy but humans harvest a morsel. Taking this into account a numerical study is proposed on wind energy harvesting from a speeding subway train. Subways trains generate a remarkable gust of wind that can be transferred to useful electrical energy on daily basis. To this aim, a numerical analysis is modeled by placing Savonius wind turbine in a subway tunnel to crop the wind energy produced from the speeding train. The passage of train in the tunnel generates very high velocity slipstreams along the length of the tunnel. The slipstream phenomena develop a boundary layer regime that will be absorbed by the Savonius wind turbine to self-start and generate power. In the present study, a two-dimensional numerical simulation with modified turbine blade design is carried out using open source tool OpenFOAM® with PimpleDyMFoam solver coupled with six degrees of freedom mesh motion solver sixDoFRigidBodyMotion and k–ɛ turbulence modeling, to measure the amount of torque predicted by the rotor from the gust of wind produced by the speeding train in the tunnel. Being a self-start turbine with no yaw mechanism required the turbine collects air from any direction and converts it into useful power.


2020 ◽  
Vol 8 (2) ◽  
pp. 34-37
Author(s):  
Gian Roni Ignatius ◽  
Agus Sugiri ◽  
Ahmad Suudi

The need for electricity in Indonesia becoming increasingly part of people's needs. Fossil fuels suchas oil and coal used as the main material for producing electrical energy the more limitedavailability, especially in its use of fossil fuels that pollute the environment. Wind energy is arenewable energy source that could potentially be developed. Wind energy is clean and does notpollute the environment in utilization into mechanical or electrical energy. The conversion of windenergy into electrical energy by converting this energy into mechanical rotation. In the wind energyutilization process made a tool to convert wind energy into electrical energy, that is windturbines.Wind turbine or windmill is a tool for converting wind energy. Wind turbines transformkinetic energy into mechanical energy in the form of a round shaft. Shaft speed is then used to rotatethe dynamo or a generator which produces electricity. The research was carried out on a horizontalaxis wind turbine NACA 4412, diameter 1 m, the number of blades 3 pieces and variations in windspeed 2-8 m / s. Results showed the greatest lift (CL) at 14o angle of attack with a value of 1.583.The driving force of the smallest (CD) at an angle of attack -4o to 2o with a value of 0.008. Value CL/ CD was found in the angle of attack of 6o with a value of 93.057. The maximum power generatedby 484.63 Watt. Wind speed, the number of blades, angle of attack and the election of the airfoileffect on the generated power.Keywords : wind energy, wind turbines, airfoil NACA 4412.


2020 ◽  
Author(s):  
Xiaoyu Zhou ◽  
Vesselina Roussinova ◽  
Vesselin Stoilov

Abstract This paper investigates the performance of vortex-induced vibration (VIV) energy harvester in low-speed water flow. The proposed VIV harvester is extracting hydrokinetic energy from the flowing current and transferring it into mechanical vibrations. The vibrations are further converted into electrical energy using the piezoelectric transducer to supply the modern demand for energy-consumption. To meet the demand, the single harvester is analyzed to determine the suitable geometry for the bluff body that is sensitive to the low-speed flow. Furthermore, the converter must be able to harvest vibrations of varying amplitudes and frequencies. To maximize the power output, different array configurations of multiple bluff bodies are examined. A single positively buoyant elastically mounted cylinder is tested experimentally and at a low flow speed of 0.3 m/s, it can harvest vibrations with an average frequency of 1.8 Hz and peak to peak amplitude of 1.5d, where d is the diameter of the bluff body. It was found that for an array consisting of ten bluff bodies, the average frequency and peak to peak amplitude increases to 2.09Hz and 1.54d, respectively.


2019 ◽  
Vol 4 (1) ◽  
pp. 41-46 ◽  
Author(s):  
Da Xiao ◽  
Ying Yang ◽  
Qinlong Shen ◽  
Jiamei Jin ◽  
Yiping Wang

Abstract In this study, a piezoelectric wind energy harvester was vibrated that aims to convert high-speed wind energy into electrical energy using vibrations caused by centrifugal force. Vibrations induced by centrifugal force enabled effective distortion of the piezoelectric clamped beam and thus produced electric charge through the piezoelectric effect. A clamped beam was used rather than a conventional thin cantilever to harvest the wind energy in the proposed harvester. The centrifugal force was introduced by a pair of rotating eccentric turbines that are installed on two ball bearings on both sides of the piezoelectric unimorph. Benefiting from the rotating eccentric masses of these turbines, the harvester is capable of capturing wind energy in high speed wind environments. A prototype was set up to examine the effects of the wind speed and the structural parameters on the electrical output of the harvester. It is found that the harvester worked efficiently with wind applied from the axial directions in a 20–55 m/s speed range and produced a maximum open-circuit voltage of 47.2 V. When connected to an external load of 50 kΩ, the harvester showed a peak output power of 3.69 mW at a wind speed of 55 m/s.


Author(s):  
Conrado F. Ostia ◽  
Riza Marie G. Baylon ◽  
Charneth Noe Cate B. Pancho ◽  
Joseph Immanuel M. Talamera ◽  
Giovanni M. Viado ◽  
...  

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