An Economic Evaluation of Small-Scale Wind-Powered Electric Generation Systems

1979 ◽  
Vol 101 (2) ◽  
pp. 213-216
Author(s):  
J. L. Obermeier ◽  
H. W. Townes

Presented is an economic evaluation of several commercial wind-powered electric generation systems of the type which could be used by an individual homeowner. A system includes a wind plant, tower, storage battery, and dc to ac inverter. The analysis considered a total of 12 different system configurations. The evaluation of energy output was based on wind speed data for several locations in the state of Montana. The analysis can be extended to other locations on the basis of mean annual wind speed. The results of the evaluation indicate that some of the “home built” systems are competitive economically at the present time in some “windy” locations. None of the systems which are economic could individually supply the entire power requirement for a single-family dwelling.

Author(s):  
Ewelina Krawczak

The community all over the World has to tackle the problem of depletion of fossil fuels, overusing the natural resources, and growing emission of greenhouse gases into the atmosphere. It is related to the growing demand for electricity due to global development in every field. The solution to this problem can be production clean, solar energy with the use of photovoltaic modules. However, the installation of PV system in urban areas is very often impossible because of high-density citie’s architecture. The objective of this study was to analyze building applied photovoltaic system configurations for the flat rooftop of the detached house in Warsaw, Poland. Four configurations were analyzed taking into consideration the area of the rooftop, different tilt angles of PV modules, and shading areas. The system configuration as well as monthly energy output were carried out by the use of DDS-Cad software. The ecological aspect of the photovoltaic installation was also analyzed. A significant reduction of greenhouse gases was observed based on conducted calculations.


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3598
Author(s):  
Sara Russo ◽  
Pasquale Contestabile ◽  
Andrea Bardazzi ◽  
Elisa Leone ◽  
Gregorio Iglesias ◽  
...  

New large-scale laboratory data are presented on a physical model of a spar buoy wind turbine with angular motion of control surfaces implemented (pitch control). The peculiarity of this type of rotating blade represents an essential aspect when studying floating offshore wind structures. Experiments were designed specifically to compare different operational environmental conditions in terms of wave steepness and wind speed. Results discussed here were derived from an analysis of only a part of the whole dataset. Consistent with recent small-scale experiments, data clearly show that the waves contributed to most of the model motions and mooring loads. A significant nonlinear behavior for sway, roll and yaw has been detected, whereas an increase in the wave period makes the wind speed less influential for surge, heave and pitch. In general, as the steepness increases, the oscillations decrease. However, higher wind speed does not mean greater platform motions. Data also indicate a significant role of the blade rotation in the turbine thrust, nacelle dynamic forces and power in six degrees of freedom. Certain pairs of wind speed-wave steepness are particularly unfavorable, since the first harmonic of the rotor (coupled to the first wave harmonic) causes the thrust force to be larger than that in more energetic sea states. The experiments suggest that the inclusion of pitch-controlled, variable-speed blades in physical (and numerical) tests on such types of structures is crucial, highlighting the importance of pitch motion as an important design factor.


Südosteuropa ◽  
2019 ◽  
Vol 67 (2) ◽  
pp. 175-195
Author(s):  
Petru Negură

Abstract The Centre for the Homeless in Chișinău embodies on a small scale the recent evolution of state policies towards the homeless in Moldova (a post-Soviet state). This institution applies the binary approach of the state, namely the ‘left hand’ and the ‘right hand’, towards marginalised people. On the one hand, the institution provides accommodation, food, and primary social, legal assistance and medical care. On the other hand, the Shelter personnel impose a series of disciplinary constraints over the users. The Shelter also operates a differentiation of the users according to two categories: the ‘recoverable’ and those deemed ‘irrecoverable’ (persons with severe disabilities, people with addictions). The personnel representing the ‘left hand’ (or ‘soft-line’) regularly negotiate with the employees representing the ‘right hand’ (‘hard-line’) of the institution to promote a milder and a more humanistic approach towards the users. This article relies on multi-method research including descriptive statistical analysis with biographical records of 810 subjects, a thematic analysis of in-depth interviews with homeless people (N = 65), people at risk of homelessness (N = 5), professionals (N = 20) and one ethnography of the Shelter.


1985 ◽  
Vol 107 (3) ◽  
pp. 237-239
Author(s):  
R. W. Baker

The hourly wind speed data collected over a six-year period at four wind power measurement locations are used to estimate the annual energy output of a large wind turbine generator. The interannual energy and wind speed variations are discussed. The estimated interannual energy output at each location is related to the mean annual wind speed variation. The data indicate that at three of the four locations the estimated interannual energy variation varied as the square of the mean annual wind speed variation. That is, a 10 percent increase in the mean annual wind speed resulted in a 20 percent increase in the annual energy output. At the fourth location there was an approximate linear relationship.


2010 ◽  
Vol 28 (7) ◽  
pp. 539-553 ◽  
Author(s):  
Paul Gavaza ◽  
Karen L. Rascati ◽  
Abiola O. Oladapo ◽  
Star Khoza

1882 ◽  
Vol 33 (216-219) ◽  
pp. 257-258

The new cell consists of a flat copper case, of the same shape as a Grove’s cell; it has a lid of paraffined wood, from which hangs a plate of lead amalgamated with mercury, the lower part of the lead plate being held in a groove in a slip of paraffined wood resting on the bottom of the copper case: through the lid a hole is bored for the introduction of the solution, which consists of a solution of cupric sulphate, to which is added one-twelfth of hydric sulphate; the presence of this free sulphuric acid improves the cell at once. The following sectional sketch shows the arrangement:- AB. The outer flat copper case. C. Plate of amalgamated lead held in grooves in the cap D and the slip E. F shows the hole in the cap through which the solution is introduced, and by the introduction of a glass tube through this hole the state of the charge is seen by observing the colour; the interior surface of the case forms the negative, and the amalgamated lead the positive electrode.


2020 ◽  
Vol 29 (5) ◽  
pp. 74-88
Author(s):  
Aleksandr Larichev ◽  
Emil Markwart

Local government as a political, legal and social institution finds itself in a very difficult period of development in Russia. The long-established tendency of its subordination to the state has intensified today in connection with the newly adopted constitutional amendments. At the same time, it seems obvious that further “embedding” of local government into the state management vertical, in the absence of any positive effect in terms of solving socio-economic and infrastructural problems, will inevitably lead to other hard to reverse, negative results both for local government institutions and the system of public authority as a whole. The normal functioning of local government requires, however, not only the presence of its sufficient institutional and functional autonomy from the state, but also an adequate territorial and social base for its implementation. To ensure the formation of viable territorial collectives, especially in urban areas, it seems appropriate to promote the development of self-government based on local groups at the intra-municipal level. Such local groups can independently manage issues of local importance on a small scale (landscaping, social volunteering, and neighborly mutual assistance), and provide, within the boundaries of a local territory, due civil control over the maintenance by municipal authorities of more complex and large-scale local issues (repair and development of infrastructure, removal of solid household waste and more). At the same time, the development of local communities can by no means be a self-sufficient and substitutional mechanism, whose introduction would end the need for democracy in the full scope of municipal structures overall. In this regard, the experience of local communities’ development in Germany, a state with legal traditions similar to Russian ones, with a centuries-old history of the development of territorial communities and a difficult path to building democracy and forming civil society, seems to be very interesting. Here, the progressive development of local forms of democracy and the participation of residents in local issue management are combined with stable mechanisms of municipal government, and the interaction of municipalities with the state does not torpedo the existing citizen forms of self-government. At the same time, the experience of Germany shows that the decentralization of public issue management which involves the local population can only be effective in a situation where, in addition to maintaining a full-fledged self-government mechanism at the general municipal level, relevant local communities are endowed with real competence and resources to influence local issue decision-making. The role of formalized local communities in urban areas, as the German experience shows, can not only facilitate the decentralization of solving public problems, but can also help in timely elimination of triggers for mobilizing citywide supercollectives with negative agendas. This experience seems useful and applicable in the Russian context.


Author(s):  
Yi Zhang ◽  
Ka Chung Chan ◽  
Sau Chung Fu ◽  
Christopher Yu Hang Chao

Abstract Flutter-driven triboelectric nanogenerator (FTENG) is one of the most promising methods to harvest small-scale wind energy. Wind causes self-fluttering motion of a flag in the FTENG to generate electricity by contact electrification. A lot of studies have been conducted to enhance the energy output by increasing the surface charge density of the flag, but only a few researches tried to increase the converting efficiency by enlarging the flapping motion. In this study, we show that by simply replacing the rigid flagpole in the FTENG with a flexible flagpole, the energy conversion efficiency is augmented and the energy output is enhanced. It is found that when the flag flutters, the flagpole also undergoes aerodynamic force. The lift force generated from the fluttering flag applies a periodic rotational moment on the flagpole, and causes the flagpole to vibrate. The vibration of the flagpole, in turn amplifies the flutter of the flag. Both the fluttering dynamics of the flags with rigid and flexible flagpoles have been recorded by a high-speed camera. When the flag was held by a flexible flagpole, the fluttering amplitude and the contact area between the flag and electrode plates were increased. The energy enhancement increased as the flow velocity increased and the enhancement can be 113 times when the wind velocity is 10 m/s. The thickness of the flagpole was investigated. An optimal output of open-circuit voltage reaching 1128 V (peak-to-peak value) or 312.40 V (RMS value), and short-circuit current reaching 127.67 μA (peak-to-peak value) or 31.99 μA (RMS value) at 12.21 m/s flow velocity was achieved. This research presents a simple design to enhance the output performance of an FTENG by amplifying the fluttering amplitude. Based on the performance obtained in this study, the improved FTENG has the potential to apply in a smart city for driving electronic devices as a power source for IoT applications.


Author(s):  
Bowen Yan ◽  
Yangjin Yuan ◽  
Dalong Li ◽  
Ke Li ◽  
Qingshan Yang ◽  
...  

The semi-periodic vortex-shedding phenomenon caused by flow separation at the windward corners of a rectangular cylinder would result in significant vortex-induced vibrations (VIVs). Based on the aeroelastic experiment of a rectangular cylinder with side ratio of 1.5:1, 2-dimensional (2D) and 2.5-dimensional (2.5D) numerical simulations of the VIV of a rectangular cylinder were comprehensively validated. The mechanism of VIV of the rectangular cylinder was in detail discussed in terms of vortex-induced forces, aeroelastic response, work analysis, aerodynamic damping ratio and flow visualization. The outcomes showed that the numerical results of aeroelastic displacement in the cross-wind direction and the vortex-shedding procedure around the rectangular cylinder were in general consistence with the experimental results by 2.5D numerical simulation. In both simulations, the phase difference between the lift and displacement response increased with the reduced wind speed and the vortex-induced resonance (VIR) disappeared at the phase difference of approximately 180∘. The work done by lift force shows a close relationship with vibration amplitudes at different reduced wind speeds. In 2.5D simulations, the lift force of the rectangular cylinder under different wind speeds would be affected by the presence of small-scale vortices in the turbulence flow field. Similarly, the phase difference between lift force and displacement response was not a constant with the same upstream wind speed. Aerodynamic damping identified from the VIV was mainly dependent on the reduced wind speed and negative damping ratios were revealed at the lock-in regime, which also greatly influenced the probability density function (PDF) of wind-induced displacement.


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