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Ocean Renewable Power Company, Inc. (ORPC) recently completed an EU Horizon 2020 funded project to develop and test a “wet-gap” generator for use with their tidal and river energy converters. This wet-gap system is designed for a normal operating condition of a seawater flooded electrical generator which would typically be air or oil filled. This development removes the need for insulating oil…
Savoniusturbinesare practical for rivers with low speeds due to their simple design and good self-starting capabilities. Despite these advantages, real implementation is still limited due to their low power efficiency. However, the experimental studies are scarce as they mainly focus on power performance, neglecting the impact of materials exposed to the wind or water medium. Therefore, the…
In the present paper, three-dimensional numerical simulations were carried out to examine the influence of the overlap ratio between the two straight edges on the advancing and returning blades of the novel V-shapedrotor bladeprofiles using thesliding meshtechnique. The performance parameters were computed with respect to the tip speed ratio. The findings show that the coefficient of torque…
Although hydrokinetic turbines offer many benefits their installation and operation also present challenges. Similar to other riverine structures, a key issue facing the hydrokinetic structures is the trapping of sediment and debris (organic and non-organic). This issue impacts the financial feasibility of projects as well as posing environmental concerns. The trapping of sediment and debris…
The BladeRunner Energy hydrokinetic turbine A kw-scale prototype of the BladeRunner system was tested at the Tanana River Test Site in Nenana, AK in the fall of 2021 and the summer of 2022. The BladeRunner hydrokinetic turbine uses a flexible torsional cable to connect a submerged trailing rotor to a floating generator housing that is supported by a single mooring line. The BladeRunner design…
When the swept area of an array of current turbines occupies a substantial fraction of a channel’s cross-section, their unit performance is augmented. In moderate confinement, power coefficients for individual turbines may exceed the Betz-Lanchester-Zhukowsky limit, and, in practice, exceed unity by drawing on both kinetic and potential energy embodied in the flow. This effect has long been…
We introduce a methodology for a comprehensive characterization of river flows from transects surveyed at different times over near coincident transects from acoustic Doppler current profiler (ADCP) data acquired from a moving vessel.
The ADCP measurements are first rotated from East and North velocities into primary and secondary flows that are projected onto a grid of points on an…
Many remote communities in Alaska have significant hydrokinetic resources. However, the remote locations make collecting large amounts of resource data challenging and costly. Through accurately up sampling hourly ADCP data, we are seeking ways to faithfully reproduce annual energy estimates for velocity time series with high enough temporal resolution to be useful for grid-modeling tools.…
The worldwide river and tidal hydrokinetic power potential is considerable. Harnessing such potential could allow the generation of a significant amount of sustainable electricity for local uses. To the present, most studies on hydrokinetic power have focused on large-scale commercial technology development, large tidal farms planning, and high-intensity resources assessment. Reduced attention…
The Igiugig Village Council (IVC) installed and operates a marine energy device, the ORPC RivGen® PowerSystem, in the Kvichak River in Igiugig, Alaska. As required by IVC’s 2019 FERC license to operate thepower system, a Fish Monitoring Plan was developed and implemented for collecting images fromunderwater cameras to assess the interaction of sockeye salmon with the RivGen Power System.…
Free-flowing rivers have been impacted by anthropogenic activity and extensive hydropower development. Despite this, many opportunities exist for context-specific energy extraction, at locations deemed undesirable for conventional hydropower plants, in ways that reduce the scale of operation and impact. Hydrokinetic energy conversion is a renewable energy technology that requires accurate…
The volume penalization vortex-in-cell (VP-VIC) method, which combines the vortex-in-cell and vortex penalization methods, is a kind of immersed boundary method that has the advantage of accurately calculating the vorticity field near the boundary. It is expected to be used as a design tool for shape optimization. In this study, the flow and performance of a small Savonius turbine rotor (rotor…
Coaxial horizontal axis hydrokinetic turbine system: Numerical modeling and performance optimization
Hydrokinetic turbines extract energy from free-flowing water, such as river streams and marine currents. For river applications, the typical deployment location is highly space-constrained due to both the nature of the river (i.e., its natural width and depth) and the other usages of the river. Therefore, a modified design of a conversion device is desired to accommodate these space…
This study focuses on the interaction between the water free surface, the riverbed, and some Darrieus-type hydrokinetic turbines deployed in river flows. As turbines offer a resistance to the flow, they affect the upcoming velocity, which in turn affects their performance. The proximity of the neighboring deformable free surface or rigid bed may also influence their power extraction. In this…
The supply of energy is sustainable only if it is predominantly based on renewable or regenerative energies. For this reason, the use of micro-hydropower plants on rivers and streams is considered recently. This is a particular challenge for the preservation of ecologically permeable streams, so that no dams or similar structures can be considered. While the axial turbine design has prevailed…
The current study presents flow measurements around a hydrokinetic turbine using a Horizontal Acoustic Doppler Current Profiler (HADCP). HADCPs are often used to estimate the water discharge rate and flow velocity however, they can also be used to characterize the near-surface flows; this includes the wake generated by a surface mounted hydrokinetic turbine. Tests are conducted around a 22-kW…
The potential for dangerous interactions with floating debris is a leading consideration when evaluating potential sites for deployment of hydrokinetic power systems, yet to date, relatively little research effort has been directed towards developing and proving effective devices and systems for protecting turbines from floating debris.
This paper presents and discusses results from a…
Passive turbulence control of flow induced motion of a cylinder using strips has been practiced for over 30 years. The two distinct physical characteristics of strips: thickness and roughness, can have coupled effects on altering the flow induced motion. The experimental work discussed here decouples these two effects for augmented energy extraction. Tests with cylinders attached with strips…
ocial and political concerns on climate change have made renewable energy an essential component of government’s work plans. Grid-connected horizontal-axishydrokineticturbinesare promising eco-friendly power sources for electrical energy supply to households near middle-to-high discharge rivers, while providing an opportunity to sell the energy surplus. In this work, a rotor design analysis of…
Hydrokineticpoweras acleanrenewableenergy has been aroused awidespread concern. Horizontal axis turbines are widely used in the field of tidal and river current energy power generation, but their internal flow loss characteristics have not been fully revealed. In this paper, a micro horizontal axis river ducted turbine is taken as the research object, and the flow loss characteristics of the…
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