scholarly journals Parametric analysis of gravity Vortex turbines as a low cost renewable energy alternative from low head hydraulic resources

2020 ◽  
Vol XXIII (1) ◽  
pp. 22-28
Author(s):  
Deniz Ünsalan

The long existent worldwide trend for large scale hydroelectric power plants, relying on dams are now under severe criticism for the large areas their reservoirs occupy, which are often fertile agricultural areas and sometimes flood cultural heritage sites. However, there are also environment-friendly alternatives for hydroelectric power production, which are capable to obtain energy from small scale streams with relatively low heads. Such smaller scale sources with low cost facilities can be used for electric production by alternative schemes that use small streams, irrigation canals and divertions from rivers, tidal pools, overtopping wave energy converters and urban wastewater. One of the recent types of such plants are the gravity vortex turbines that use the naturally occurring “sink vortex” draining such water. They are highly efficient and able to obtain energy from sources with flow rates as low as 1 m3/s and heads as low as 0.80 m. Such water sources are abundant in most of the rural areas and it is possible to obtain either an important part or the total need of the energy requirement of the nearby communities with such systems. Gravity vortex turbines have low costs due to their simple structure and are easy to maintain. They can also be implemented for overtopping wave energy and tidal energy systems, as well as recovery units of pumped energy storage schemes. The purpose of this paper is to propose relations for the design and parametric analysis to size the relevant parts of the plant- the pool and the turbine. Potential flow is assumed throughout the analysis. Attempts to obtain optimized relations between the relative sizes and rotational speeds for the pool, water source, turbine are made and inputs for preliminary design are obtained.

Author(s):  
A. F. Khan ◽  
K. Khurshid ◽  
N. Saleh ◽  
A. A. Yousuf

Orthogonally Projected Area (OPA) of a geographical feature has primarily been studied utilizing rather time consuming field based sampling techniques. Remote sensing on the contrary provides the ability to acquire large scale data at a snapshot of time and lets the OPA to be calculated conveniently and with reasonable accuracy. Unfortunately satellite based remote sensing provides data at high cost and limited spatial resolution for scientific studies focused at small areas such as micro lakes micro ecosystems, etc. More importantly, recent satellite data may not be readily available for a particular location. This paper describes a low cost photogrammetric system to measure the OPA of a small scale geographic feature such as a plot of land, micro lake or an archaeological site, etc. Fitted with a consumer grade digital imaging system, a Rokkaku kite aerial platform with stable flight characteristics is designed and fabricated for image acquisition. The data processing procedure involves automatic Ground Control Point (GCP) detection, intelligent target area shape determination with minimal human input. A Graphical User Interface (GUI) is built from scratch in MATLAB to allow the user to conveniently process the acquired data, archive and retrieve the results. Extensive on-field experimentation consists of multiple geographic features including flat land surfaces, buildings, undulating rural areas, and an irregular shaped micro lake, etc. Our results show that the proposed system is not only low cost, but provides a framework that is easy and fast to setup while maintaining the required constraints on the accuracy.


Meccanica ◽  
2021 ◽  
Vol 56 (5) ◽  
pp. 1223-1237
Author(s):  
Giacomo Moretti ◽  
Andrea Scialò ◽  
Giovanni Malara ◽  
Giovanni Gerardo Muscolo ◽  
Felice Arena ◽  
...  

AbstractDielectric elastomer generators (DEGs) are soft electrostatic generators based on low-cost electroactive polymer materials. These devices have attracted the attention of the marine energy community as a promising solution to implement economically viable wave energy converters (WECs). This paper introduces a hardware-in-the-loop (HIL) simulation framework for a class of WECs that combines the concept of the oscillating water columns (OWCs) with the DEGs. The proposed HIL system replicates in a laboratory environment the realistic operating conditions of an OWC/DEG plant, while drastically reducing the experimental burden compared to wave tank or sea tests. The HIL simulator is driven by a closed-loop real-time hydrodynamic model that is based on a novel coupling criterion which allows rendering a realistic dynamic response for a diversity of scenarios, including large scale DEG plants, whose dimensions and topologies are largely different from those available in the HIL setup. A case study is also introduced, which simulates the application of DEGs on an OWC plant installed in a mild real sea laboratory test-site. Comparisons with available real sea-test data demonstrated the ability of the HIL setup to effectively replicate a realistic operating scenario. The insights gathered on the promising performance of the analysed OWC/DEG systems pave the way to pursue further sea trials in the future.


Author(s):  
Jian Song ◽  
Chun-wei Gu

Energy shortage and environmental deterioration are two crucial issues that the developing world has to face. In order to solve these problems, conversion of low grade energy is attracting broad attention. Among all of the existing technologies, Organic Rankine Cycle (ORC) has been proven to be one of the most effective methods for the utilization of low grade heat sources. Turbine is a key component in ORC system and it plays an important role in system performance. Traditional turbine expanders, the axial flow turbine and the radial inflow turbine are typically selected in large scale ORC systems. However, in small and micro scale systems, traditional turbine expanders are not suitable due to large flow loss and high rotation speed. In this case, Tesla turbine allows a low-cost and reliable design for the organic expander that could be an attractive option for small scale ORC systems. A 1-D model of Tesla turbine is presented in this paper, which mainly focuses on the flow characteristics and the momentum transfer. This study improves the 1-D model, taking the nozzle limit expansion ratio into consideration, which is related to the installation angle of the nozzle and the specific heat ratio of the working fluid. The improved model is used to analyze Tesla turbine performance and predict turbine efficiency. Thermodynamic analysis is conducted for a small scale ORC system. The simulation results reveal that the ORC system can generate a considerable net power output. Therefore, Tesla turbine can be regarded as a potential choice to be applied in small scale ORC systems.


2020 ◽  
Author(s):  
Brian Post ◽  
Phillip Chesser ◽  
Alex Roschli ◽  
Lonnie Love ◽  
Katherine Gaul

2015 ◽  
Vol 2 (2) ◽  
pp. 513-536 ◽  
Author(s):  
I. Grooms ◽  
Y. Lee

Abstract. Superparameterization (SP) is a multiscale computational approach wherein a large scale atmosphere or ocean model is coupled to an array of simulations of small scale dynamics on periodic domains embedded into the computational grid of the large scale model. SP has been successfully developed in global atmosphere and climate models, and is a promising approach for new applications. The authors develop a 3D-Var variational data assimilation framework for use with SP; the relatively low cost and simplicity of 3D-Var in comparison with ensemble approaches makes it a natural fit for relatively expensive multiscale SP models. To demonstrate the assimilation framework in a simple model, the authors develop a new system of ordinary differential equations similar to the two-scale Lorenz-'96 model. The system has one set of variables denoted {Yi}, with large and small scale parts, and the SP approximation to the system is straightforward. With the new assimilation framework the SP model approximates the large scale dynamics of the true system accurately.


2021 ◽  
Vol 2115 (1) ◽  
pp. 012026
Author(s):  
Sonam Solanki ◽  
Gunendra Mahore

Abstract In the current process of producing vermicompost on a large-scale, the main challenge is to keep the worms alive. This is achieved by maintaining temperature and moisture in their living medium. It is a difficult task to maintain these parameters throughout the process. Currently, this is achieved by building infrastructure but this method requires a large initial investment and long-run maintenance. Also, these methods are limited to small-scale production. For large-scale production, a unit is developed which utilises natural airflow with water and automation. The main aim of this unit is to provide favourable conditions to worms in large-scale production with very low investment and minimum maintenance in long term. The key innovation of this research is that the technology used in the unit should be practical and easy to adopt by small farmers. For long-term maintenance of the technology lesser number of parts are used.


2018 ◽  
Vol 43 (2) ◽  
pp. 95-106
Author(s):  
András Schlett ◽  
Judit Beke

Large-scale farming that utilizes industrial methods to intensify production is becoming more significant worldwide. This study explores this phenomenon and sheds light on its consequences. Contingency factors serve as key drivers when determining the advantages and disadvantages of both large-scale and small-scale farming. Significant shifts in agro-production methods have fundamentally altered ownership and production structures in agriculture and had a disastrous impact on the livelihoods of people living in rural areas.


2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Francesco Paparella ◽  
Satja Sivcev ◽  
Daniel Toal ◽  
John V. Ringwood

The measurement of the motion of a small-scale wave energy device during wave tank tests is important for the evaluation of its response to waves and the assessment of power production. Usually, the motion of a small-scale wave energy converter (WEC) is measured using an optical motion tracking system with high precision and sampling rate. However, the cost for an optical motion tracking system can be considerably high and, therefore, the overall cost for tank testing is increased. This paper proposes a low-cost capture system composed of an inertial measurement unit and ultrasound sensors. The measurements from the ultrasound sensors are combined optimally with the measurements from the inertial measurement unit through an extended Kalman filter (EKF) in order to obtain an accurate estimation of the motion of a WEC.


2020 ◽  
Vol 12 (19) ◽  
pp. 8142
Author(s):  
Wubamlak Ayichew Workneh ◽  
Jun Takada ◽  
Shusuke Matsushita

Sectoral economic growth data in Ethiopia show that the agriculture sector has the lowest growth, which is caused by frequent drought and inefficient technologies, among other factors. As a result, the productivities of land and labor, as well as the income of small-scale farm households, are very low, and rural areas have a relatively high poverty rate. A quasi-experiment was applied to understand the impact of using small-scale irrigation motor pumps on farmers’ livelihood improvement. Specifically, a survey was conducted in 2019 on a sample of 92 small-scale irrigation motor pump and canal irrigation users as the treatment and control groups. The weighted propensity score matching method was applied to eliminate initial differences and adjust sampling proportions across the groups. Based on the average treatment effect on the treated estimation results, we cannot state that the mean income difference in small-scale irrigation motor pump users and canal irrigation system users is different from zero. This indicates that countries with little capital to invest in large-scale irrigation projects can introduce household-level small-scale irrigation motor pumps to improve farmers’ incomes.


Author(s):  
Antonius Ibi Weking ◽  
Yanu Prapto Sudarmojo

Development of new and renewable energy source always developed by world researchers which one of those is energy source from water, because it’s friendly for environment and low cost. Water is one of energy source which it’s have big potential in all Indonesian territory. The main problem from microhydropower plants is a water discharge which it’s flow is not continued every year because influenced by weather season. Micro Hydro is a microhydro power plants (MHP)in a small scale. A micro hydro can be operated in a certain of time if it has a enough water supply. To knowing a right of micro hydro’s  characteristic is not easy thing to learn it. It is because a characteristic each of micro hydro’s installation location is considered specific location.               One type of micro hydro is using Archimedes Screw Turbine. Udayana University of Electrical Engineering Department in this time not have a facility for hydropower field to use this model, so a college student not yet to receive a knowledge of this. Through this research, a writer want to expand a college student’s knowledge in hydropower field with create a prototype of micro hydro with Archimedes Screw Turbine to hydropower practical in laboratory. In this research the effect of screw’s height angle conversion and effect of water pressure conversion has to be researched. In this study will discuss the influence of water pressure and slope of the altitude angle on the rotation produced by the Archimedes screw turbine so that it can be seen the voltage, current, power generated by the generator, torque and efficiency . The result of from handmade equipment for this research in angle 40­0 with biggest generator round (rpm) is 3768 (rpm) and highest power is 10.92057 watt, torque adalah 0.60 Nm dan efisiensi sebesar 14 %. The torque which resulted from water pressure 24 psi is 0,73 Nm and efficience 18,01 %. The voltage, current, and output power which resulted in generator is 85,8 Volt, 0,1963 Ampere and 16,85 Watt. For generator speed round in the pressure 24 Psi is 4582 rpm, while turbine speed round which resulted from the pressure 24 Psi is 383 rpm before coupled with generator and 222 rpm after coupled with generator.


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