Abstract: In small-scale hydropower scheme, the most important component is electro-mechanical equipment. Since cost contribution of this component is high because hydrokinetic projects require negligible civil works. Turbine and alternator contribute a major fraction of the hydrokinetic projects. Thus, there is a requirement to estimates the electromechanical equipment cost for a hydrokinetic hydropower scheme. The present paper investigates design parameters of the hydrokineticturbines and intends to develop cost correlation which depends on most critical parameters of hydropower sites such as velocity and power capacity. In this present work, three zero head turbines are considered including straight blade Darrieus, two Stage Savonius, and Gorlov Helical. The size and cost of major components have been calculated based on material, manufacturing, research and design, and assembly costs. Based on cost and site parameters, cost correlation has been developed. The obtained cost has been validated with available zero head turbines in the market and installed projects. A techno-economic analysis has been carried out to select economical hydrokinetic turbine for river and canal application.
After the development of the wind-turbine model, the focus of the research turned towards adapting the model for hydrokineticturbines. One of the first issues to be dealt with was the effect the installation of a hydrokinetic turbine had on the upstream flow. The effect a wind turbine might have on the up-stream airflow is often of little interest. Wind turbines are installed in open areas with no significant blockage. As a result, the upstream effects of a VAWT are generally not considered in the fluid-flow analysis unless the turbines are installed in an array where the turbulence of the lead turbine can have a negative effect on the performance of the downwind turbines. However, a turbine placed in an open channel of water has a major impact on upstream flow conditions. Although much research has been devoted to increasing the efficiency of hydroelectric power from conventional dams, very little has been written on the characteristics of water turbine efficiencies in open channels with free flow and low-head resources. One cannot assume that these turbines behave according to the Betz limit the way that wind turbines do.
The rapid increase in global energy needs has generated a considerable attention to the generation of energy from renewable energy sources. Hydrokineticturbines are a vertical axis type water turbine that is very simple and appropriate for remote areas. A hydrokinetic turbine has a good performance and is capable of producing considerable torque at high water speeds. The activity in this study is to model a small hydrokinetic turbine simulated with a CFD software, by varying the position of the turbine runner in each 5runner rotation so as to obtain the pressure value between the two blades as an indicator of the force magnitude occurring or generated. In a previous study a vertical axis hydrokinetic turbine model was tested in the laboratory compared to the results with a simulated test with CFD. The laboratory test turbine performance result has a same or similar performance result calculate from the CFD simulation. From the simulation results it is seen that there are only two blades being pushed by the water flow. It is suggested to add a steering blade on the turbine output area, in order to increase the blade number to be pushed by the water flow rate. By attaching a steering blade on the output part of the turbine, the water prevents from leaving the turbine and deflected to push another blade, resulting in more water- boosting blades. To ensure that this step will produce a better result, the first step to do is simulating the turbine with a steering blade. The result obtained in every 5 runner position is that there is an increase in water pressure between the two blades. This phenomenon shows that there is an increase in the turbine performance. One of the simulation results is, at a runner position = 20,the water pressure between blade two and blade three rises from 8.15e + 009 Pa in the turbine without a steering blade, to 4.69e + 010 Pa in the turbine with a steering blade. While the water pressure between blade five and the blade six, that had a very low water pressure of 4.86e + 008 Pa, rose to 2.30e + 010 Pa, after being given a steering blade. This shows that the steering blade addition would give an additional water boost to some blades.
the wildlife habitat. This ecological impact may exceed the value of the generated electricity especially in small river streams. In order to harness power from small river streams in Kenya, a new approach has to be examined. One possible solution is to use low-head micro hydro installations, such as the Gorlov helical turbine 9 . In this research we developed a low head helical hydrokinetic water turbine coupled to a generator for power generation targeting rural areas with small river streams in Kenya. The turbine can also be utilized in urban areas especially in large sewer water pipelines for power generation. The turbine uses water currents on naturally flowing rivers for power generation 7 . Since water power is more predictable and can be gated and stored for later use, it is believed that hydrokinetic helical water turbine is the best method of extracting renewable energy compared to wind and solar. In this design of plug flow, the turbine was plugged into a stable metal frame structure and locked and once the gate is opened to some height the turbine starts to rotate until it attains the nominal speed at which power generation is realized. The orientation of helical hydrokineticturbines can be either horizontal or vertical. In this design, we chose the vertical design due to its ability to admit the flow from any direction and also the costs related to generator installation and transmission of power are extremely reduced in this design.
In this study, we present a conceptual design and feasibility analysis of a Mobile Underwater Turbine System (MUTS) for harvesting Marine Hydrokinetic Energy from the Gulf Stream. MUTS is a novel integration of hydrokineticturbines and autonomous underwater vehicles (AUVs). In addition to that, the modeling and simulation of the dyanmics and navigation control of such a vehicle is also presented. Unlike other sources of marine/river hydrokinetic energy, the gulf stream presents a challenge since it exhibits a meandering trait. This makes extracting energy from this ocean current challenging, since a stationary turbine would be rendered ineffective and inoperable for considerable periods of time throughout the year due to the meandering nature of the gulf stream. This can be mitigated by having a turbine system that can relocate when the gulf stream meanders. This can be overcome by using a relocatable energy harvester, i.e. MUTS. This would ensure that energy extraction is being maximized by the device by staying in the gulf stream at all times. Design feasibility is analyzed for three different cases: (1) MUTS periodically travels to the mainland to offload the harvested energy to the electrical grid; (2) MUTS periodically offloads the harvested energy to a nearby ship, and the ship in turn travels to the mainland to offload the harvested energy to the electrical grid; and (3) MUTS uses a transmission cable located on the seabed to transfer the harvested energy to the mainland. For the scenarios studied in this paper, we found that using a transmission cable to offload the harvested energy was the most practical and economical solution.
Various studies have been presented in wind domain, which include the relation of the pitch and the performance of the horizontal-axis turbine. However, the performance of a hydrokinetic turbine has been poorly investigated. Some studies show that the adjustment of the pitch angle may control the output power of the turbine when wind velocity changes [11–13]. Due to diﬀerences on the use of horizontal-axis turbines in various types of ﬂuids, studies on hydrokineticturbines still need to be deeply explored for knowing the parameters having a great impact on the turbine performance [14–16]. As it is widely known, the maximization of the power is fundamental in the hydrokinetic turbine design in order to improve the extraction of energy from water ﬂow; therefore, the objective of this paper is to investigate experimentally and numerically the eﬀect of the section pitch angle on the performance of a hydrokinetic turbine of 1 kW designed for a water velocity (V) of 1.5 m/s with a tip speed ratio (λ) of 6.325; an initial angle of attack (α) and pitch angle (θ) of 5 ◦ and 0 ◦ , respectively; a power coeﬃcient (C p ) of 0.4382; a drive train eﬃciency (η) of 70 % and a S822 hydrofoil proﬁle. The turbine consists of a rotor with three blades of radius (R) equal to 0.79 m. The experimental investigations on the performance of a scale-model three-blades operating under diﬀerent water velocities were conducted in a recirculating water channel.
In renewable energy sources, hydrokineticturbines sector is growing fast with several new concepts and prototypes being developed in many countries. Most of them are using horizontal axis rotor or vertical axis rotor blades, but this type of turbine are not use full in shallow water sites. So the use of oscillating hydrofoils are an interesting alternative to rotating blades turbine. The concept offers an obvious advantage in shallow water sites due to its rectangular extraction plane, allowing possibility to scale up rated power by simply increasing the turbine hydrofoil span.
Tidal stream energy, due to its high level of consistency and predictability, is one of the feasible and promising type of renewable energy for future development and investment. Applicability of Blade Element Momentum (BEM) method for modeling the interaction of turbines in tidal arrays has been proven in many studies. Apart from its well-known capabilities, yet there is scarcity of research using BEM for the modeling of tidal stream energy farms considering full scale rotors. In this paper, a real geographical site for developing a tidal farm in the southern coasts of Iran is selected. Then, a numerical methodology is validated and calibrated for the selected farm by analyzing array of turbines. A linear equation is proposed to calculate tidal power of marine hydrokineticturbines. This methodology narrows down the wide range of turbine array configurations, reduces the cost of optimization and focuses on estimating best turbine arrangements in a limited number of positions.
Abstract— with the extinction of conventional sources of energy and with the emergence of renewable energy, the study of different mechanical devices to extract energy from these renewable sources has been increased drastically in recent era. In this context, to extract the kinetic energy of the flowing water, hydrokineticturbines have become popular in these days. There are several turbines which are used as hydrokinetic turbine, like Savonius turbine, Darrieus turbine and Axial flow turbine. Among these turbines, Axial flow turbine draws special attention due to its high co-efficient of power (C P ). In spite of higher C P , this turbine is not explored
The hydrokineticturbines fall under reaction type turbine and they have similar working principles as wind turbines which are to convert the hydrokinetic power into mechanical power in the form of rotating blades (Alam, 2009). Hydrokineticturbines or water stream turbines are commonly used in river flow, canal flow, irrigation flow, and tidal current. There are two areas from which hydrokinetic power can be derived: marine and river power. Marine hydrokinetic power deals with extracting energy in the ocean from tides and currents. Whereas hydrokinetic power extracted from the river comes from kinetic energy of the flow.
It has been revealed that the published decommissioning pro- grammes have very dissimilar decommissioning timings and costs per MW installed, motivating further research into the decom- missioning programmes. To achieve this, a model taking into ac- count the key variables that affect the decommissioning operations has been designed, modelling all the sites and their characteristics included in Table 2. The model is implemented in MSExcel. The modelling presented focuses on turbines and support structures. Offshore substations and cables were excluded from the model due to a lack of input data, and will be captured in future modelling activity. It is therefore expected that the model outputs will be optimistic. The two transportation strategies previously mentioned have been modelled to recognise which is best to use depending on the wind farm ’ s characteristics.
Our observations have practical implications. Although our scope of inference is limited to certain tree bats (L. borealis, L. cinereus, and L. noctivagans), areas of turbines from the rotor- swept zone around the nacelle to near the ground (different behaviors may occur higher in the airspace), and are based on observations from just three turbines in midwestern North America, efforts to monitor bat activity near turbines (e.g., acoustic detectors and video cameras), or deter bats from turbines [e.g., devices producing startling sounds (51)] may benefit by aiming instruments from the back of the nacelle into the leeward airspace, an area where we consistently observed higher bat activity regardless of changing wind directions. Strategies for minimizing fatalities of bats at turbines currently focus on preventing blades from spin- ning during low wind periods (4, 11, 12). Our observations that tree bats show a tendency to closely investigate inert turbines and sometimes linger for minutes to perhaps hours (in the cases of clustered observations) highlight the plausibility of a scenario in which bats are drawn toward turbines in low winds, but sometimes remain long enough to be put at risk when wind picks up and blades reach higher speeds. Therefore, the frequency of in- termittent, blade-spinning wind gusts within such low-wind peri- ods might be an important predictor of fatality risk; fatalities may occur more often when turbine blades are transitioning from potentially attractive (stationary or slow) to lethal (fast) speeds. Efforts to minimize bat fatalities at wind facilities might benefit by averaging wind-speed curtailment thresholds over longer peri- ods of time (e.g., >10 min) to prevent gusts from intermittently pushing blades to lethal speed during low-wind periods. Finally, fatalities may be reducible by altering the appearance of turbines. Fewer fatalities of eastern red bats were found under turbines with flashing red aviation lights at a large wind facility in Texas (52), hinting at the possibility that supplemental lighting of turbines might make some bats less likely to mistake them for trees.
The model of HOMER is simulated for the data of BSNL exchange for the load demand as shown in fig (1) in this work we used HOMER 2.81. The objective of design of simulation model of hybrid system is to minimize the total generation costs, while satisfying the specified load has been achieved. HOMER optimize in such way to give the idea about the different selecting units such as it gives the idea about how many number of wind turbines, solar arrays, diesel generator and how many battery are used to fulfill the demand. On other words we can say that it also select
Horizontal-axis wind turbines (HAWT) get their name from the fact that their axis of rotation is horizontal. They have the main rotor shaft and electrical generator at the top of a tower, and are pointed into the wind. The variability of wind distribution and speed brings up the requirement of a gear system connected to the rotor and the generator. The gear system enables a constant speed of rotation to the generator thus enabling constant frequency generation. Turbine blades are made stiff in order to prevent the blades from being pushed into the tower by high winds. Downwind machines have also been built, as they no longer require a yaw mechanism to keep them facing the wind, and also because in high winds the blades can turn out of the wind thereby increasing drag and coming to a stop. Most of the HAWTs’ are upwind as downwind systems cause regular turbulence which may lead to fatigue.
Number of stages, The coefficient of power, coefficient of torque and no load tip speed ratio increase with increase in the Reynolds number (water velocities) for one, two and three stage hydro kinetic rotor rotors. The test conducted by Md. Nahidul Islam Khan which gave the result that under same area of turbines at each stage the maximum value of power coefficient had been found for double phase Savonius rotor and cut-in speed of single and double stage Savonius rotor is lowest as compared to three stage rotors. The output power of the prototypes can be improved by enlarging the aspect ratio of each stage . The number of stages of savonius turbine is shown in Fig.6.
produced. The standard design convention for Darrieus turbines used in high wind regions, is a chord length of about 10-20% of the length of the blade. However, the data available for the chord length for a low wind speed region is very clouded. As mentioned before, Darrieus turbines produce very low torque values at lower wind speeds. To compensate for this low torque, the chord length can be increased. Although this will solve the problem of having a lower torque, it will give rise to other issues like, a higher manufacturing cost and an increased weight which will interfere with the turbine’s ability to gain momentum quickly.
Although John Barber patented the first concept of a gas turbine in the United Kingdom in 1791, it was not until the early 1900s when the first experimental gas turbines emerged when several unsuccessful tests were conducted. Their devel- opment for electric power generation started and accelerated just before World War II. At that time however, they could not compete with steam turbines and diesel engine generators. It is not surprising that their first application was in military jet engines because of their superior power-to-weight ratio. This subsequently propelled them to become the primary power plant for both military and civilian aviation applica- tions within a relatively short period of two to three decades. However, it took longer for gas turbines to make impact on other civilian applications such as power generation and nonair transport. Nowadays, a single industrial gas turbine is capable of providing power of over 300 MW at efficiencies
Abstract- This paper centers around appraisal and plausibility study for energy equalization of stand-alone hydrokinetic power supply system with battery vitality stockpiling in remote rural electrification. This proposed system consists of hydrokinetic turbine that is connected with permanent magnet synchronous generator (PMSG) and power electronics devices. In this paper, proposed site, Dokhtawaddy river which has significant water flow velocity. And it is also near Makyiyay village at Northern Shan State in Myanmar where no the electricity access from national grid is chosen for demand side. In this research work, the all out introduced limit of the proposed system is read for vitality utilization with regular varieties which contributes 25 kW of hydrokinetic turbine and 900Ah of batteries bank. The batteries bank stores the surplus of energy when the load demand is low and discharges again the stored energy to the load when hydrokinetic power is not sufficient to supply the load. The proposed system can meet the load for every hour of the days without interruption. The results show that it is the appraisal of the average daily load requirement and available hydrokinetic power with seasonal variations.