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Number of results: 116
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Abstract

This paper studies the influence of different cooling technologies on the power density of a traction machine for heavy-duty distribution transport. A prototype induction machine is built with a housing cooling jacket, potted end-windings, entire winding cooling, and shaft cooling. Electromagnetic finite element and thermal lumped-parameter models are parameterized and verified using test bench measurements. The influence of each thermal resistance along the heat paths is studied and discussed. The results are used for studying different cooling technologies. The results indicate an improvement of the continuous power density up to 108% using shaft cooling and up to 15.6% using entire winding cooling.
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Authors and Affiliations

Benedikt Groschup
1
ORCID: ORCID
Daniel Butterweck
1
Kay Hameyer
1
ORCID: ORCID

  1. Institute of Electrical Machines (IEM), RWTH Aachen University, Schinkelstraße 4, 52062 Aachen, Germany
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Abstract

Wind constitutes one of the major environmental factors affecting the design and performance of built environment. Each country has its unique climatic wind conditions, and the way in which these are considered and implemented in the structural design, is important. An implementation or adoption of any new engineering design stipulations introduces a formidable challenge to the developers of the standards and the design profession. This has been experienced in some of the countries (e.g. the UK, Australia and the USA), where processes of modernising the outdated codifi cation took place in the past. Although both Poland and South Africa are currently at the early implementation stage of the new wind loading design stipulations, there is a major difference between the circumstances of the two countries. Poland, as an EU member state, has a compulsory obligation to adopt the new uniform standarisation requirements, within a stipulated time-frame. The South African code developers, after a thorough investigation process which will be highlighted in the paper, decided voluntarily to adopt the Eurocode as the primary model document.

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Authors and Affiliations

A. Goliger
J. Żuranski
M. Giżejowski
M. Gaczek
J. Retief
A. Kruger
P. Dunaiski
S. Fiszer
M. Ćwik
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Abstract

The research paper presents the results of the dynamic analysis of an existing bar dome subjected to wind loads. The calculation model of the structure was constructed using the finite element method. The dome was subjected to the standard wind pressure, assuming that it is operates in a harmonic manner. The numerical analyses were performed with the application of Autodesk Robot and MES3D. The analysis focused on the impact of selected factors such as the frequency of forcing, wind gustiness coefficient and structural damping on the behaviour of structures.

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Authors and Affiliations

W. Szaniec
K. Zielińska
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Abstract

On power generation and the future of Polish offshore wind farms.
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Authors and Affiliations

Paweł Flaszyński
1
Karol Mitraszewski
2
Joanna Markowska Cerić
2

  1. PAS Institute of Fluid-Flow Machinery, Gdańsk, Poland
  2. PGE Baltica sp. z o.o., Warsaw, Poland
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Abstract

A questionnaire inquiry on response to wind turbine noise was carried out on 361 subjects living in the vicinity of 8 wind farms. Current mental health status of respondents was assessed using Goldberg General Health Questionnaire GHQ-12. For areas where respondents lived, A-weighted sound pressure levels (SPLs) were calculated as the sum of the contributions from the wind power plants in the specific area.

Generally, 33.0% of respondents were annoyed outdoors by wind turbine noise at the calculated A-weighted SPL of 31-50 dB, while indoors the noise was annoying to 21.3% of them. The proportion of subjects evaluating the noise produced by operative wind turbines as annoying decreased with increasing the distance from the nearest wind turbine (27.6% at the distance of 400-800 m vs 14.3% at the distance above 800 m, p < 0.016). On the other hand, the higher was the noise level, the greater was the percentage of annoyed respondents (14.0% at SPL up to 40 dB vs 28.1% at SPL of 40-45 dB, p < 0.016). Besides noise and distance categories, subjective factors, such as general attitude to wind turbines, sensitivity to landscape littering and current mental health status, were found to have significant impact on the perceived annoyance. About 50% of variance in annoyance rating might be explained by the aforesaid subjective factors.

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Authors and Affiliations

Małgorzata Pawlaczyk-Łuszczyńska
Adam Dudarewicz
Kamil Zaborowski
Małgorzata Zamojska-Daniszewska
Małgorzata Waszkowska
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Abstract

The article presents the consequences of the introduction of EU regulation 2016/631 for power park modules (PPMs), of which wind farms are a typical example. Analysing the yearlong course of changes in the generated power, the possibility of a typical wind farm meeting the requirements for the production and absorption of reactive power was checked. It was shown that in the selected cases it was necessary to introduce additional sources of reactive power on the side of the farm’s MV.

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Authors and Affiliations

Piotr Kacejko
Paweł Pijarski
Michalina Gryniewicz-Jaworska
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Abstract

In the paper, the author presents a certain method of calculation of Horizontal Axis Wind Turbine (HAWT) performance for yawed flow conditions. The presented model is developed on the basis of propeller theory described in [23). Te model employs the results of the vortex theory of propeller combined with momentum and angular momentum theorems for the HAWT wake. In the model, the blade element is regarded as a source of tangential and axial force acting on air at actuator disk surface. The momentum equations are corrected for the effect of finite number of blades by introduction of Prandtl tip-loss factor to the equations. Thanks to the approximation of lift force coefficient vs. angle of attack by sine curve, one may get a quadratic equation for local axial velocity component. Tangential component of induced velocity may be calculated from relations obtained from vortex theory of HAWT. This allows us to avoid an iterative solution for induced velocity, unlike in most of the HAWT and propeller theories. The blade section drag is incorporated to calculations of total drag of rotor and power, when induced velocity components are known, and hence blade element angle of attack is determined. To incorporate the effect of blade element stall-delay due to blade rotation, a simple semi-empirical model proposed by Tangier and Selig has been applied. The calculations are compared with experimental data obtained at Riso 100 kW experimental turbine test site and at the Grumman Wind Stream 33 turbine modified by NREL. The comparison includes power output as well as blade element angles of attack. The presented results show that the method described in the paper underestimates performance for low speed winds, whereas for strong winds the power output is slightly overestimated. For average angles of attack, one may see that for small tip speed ratios angles of attack are overestimated. At high tip speed ratios, however, angles of attack are underestimated. It was shown that there is a need to take into account the work done by side force on the tangential inflow component to obtain correct power curves for yawed flow conditions.
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Authors and Affiliations

Piotr Strzelczyk
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Abstract

The purpose of the article is to present perspectives for the development of offshore wind farms in the leading, in this respect, country in the EU and in the world – Great Britain. Wind power plays a remarkable role in the process of ensuring energy security for Europe since in 2016 the produced wind energy met 10.4% of the European electricity demand while in 2017 it was already around 11.6%. The article analyses the capacity of wind farms, support systems offered by this country and the criteria related to the location of offshore wind farms. The research has been based on the analysis of legal acts, regulations, literature on the subject, information from websites. The article shows that in recent years, the production of energy at sea has been developing very rapidly, and the leading, in this matter, British offshore energy sector is character-ised by strong governmental support.

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Authors and Affiliations

Leszek Dawid
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Abstract

The aim of this paper is to answer the question: Are the Łódź Hills useful for electrical energy production from wind energy or not? Due to access to short-term data related to wind measurements (the period of 2008 and 2009) from a local meteorological station, the measure – correlate – predict approach have been applied. Long-term (1979‒2016) reference data were obtained from ECWMF
ERA-40 Reanalysis. Artificial neural networks were used to calculate predicted wind speed. The obtained average wind speed and wind power density was 4.21 ms⁻¹ and 70 Wm⁻¹, respectively, at 10 m above ground level (5.51 ms⁻¹, 170 Wm⁻¹ at 50 m). From the point of view of Polish wind conditions, Łódź Hills may be considered useful for wind power engineering.

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Authors and Affiliations

R. Korupczyński
J. Trajer
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Abstract

The paper aimed to get the analysis of spatial horizontal distribution of summer phyto-plankton in a small and shallow lake (Głębokie, Western Polesie, CE Poland) in relation to wind conditions occurring during the research period. The study was conducted in 2011 from 5th of July to 5th of September with eight sampling dates between. Water was sampled in the littoral zone from the depth of 0.5 m in four sites situated in different and opposite to one another lake shores. We analyzed the phytoplankton abundance by the way of chlorophyll a determination as well as the community taxonomic structure. Our research revealed that: a) the direction of the wind, which occurred during sampling might have an important role in the horizontal distribution of planktonic algal biomass within the lake; b) the geomorphology of lake surroundings probably mitigated the influence of wind on phytoplankton distribution; c) even weak or mild wind may influence phytoplankton horizontal differentiation.
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Authors and Affiliations

Wojciech Pęczuła
Monika Tarkowska-Kukuryk
Wojciech Płaska
Jacek Rechulicz
Tomasz Mieczan
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Abstract

This work analyzes the process of construction and manufacturing of a blade used in a wind turbine. The calculation scheme is presented for forces generated on the blade of a wind turbine and parameters are determined of weather conditions in which the designed element would be working. Subsequently, for the chosen aerodynamic profile the characteristics are calculated of its aerodynamic coefficients, which enables the establishing of the angle of attack which impacts the yield of wind engines. The presented process is an introduction to 3D modelling of a wind turbine’s blade and simulation of its creation in a CAM environment.
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Authors and Affiliations

Karol Tucki
Mateusz Zimoch
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Abstract

This paper presents the design method and the construction details of a subsonic low-speed wind tunnel, which has been designed to achieve the flow velocity of 35 m/s in the measurement section with expected uniform velocity field at its inlet. To achieve such objectives a very detailed design was performed using a theoretical 1D analysis and computational fluid dynamics simulations. This approach was applied to improve the flow quality along the wind tunnel sections. When the wind tunnel has been launched a direct comparison of the experimentally measured flow field in the test section and numerical simulation results was conducted. Such comparison of the simulation results with the experimental one is presented in this paper. The obtained results confirm that assumed wind tunnel design method was correct, i.e. the pressure drop in the wind tunnel has been predicted very well and drive system is effective and sufficient to accelerate the airflow to required values.
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Bibliography

[1] Barlow J.B., Rae Jr W.H., Pope A.: Low-Speed Wind Tunnel Testing. John Wiley and Sons; New York 1999.
[2] Bradshaw P., Pankhurst R.C.: The design of low-speed wind tunnels. Prog. Aerosp. Sci. 5(1964), 1–69.
[3] Anderson J.D. Jr.: Fundamentals of Aerodynamics (5th Edn.). McGraw-Hill; 2011.
[4] Kneba Z.: Modeling of the internal combustion engine cooling system. Arch. Thermodyn. 40(2019), 3, 109–121.
[5] Muszynski T., Andrzejczyk R., Park W.I., Dorao C.A.: Heat transfer and pressure drop characteristics of the silicone-based plate heat exchanger. Arch. Thermodyn. 40(2019), 1, 127–143.
[6] Mehta J., Bradshaw P.: Design rules for small low speed wind tunnels. Aeronaut. J. 83(1979), 827, 443–453.
[7] Stathopoulos T.: Design and fabrication of a wind tunnel for building aerodynamics. J. Wind Eng. Ind Aerod. 16(1984), 2–3, 361–376.
[8] Cattafesta L., Bahr C., Mathew J.: Fundamentals of wind-tunnel design. In: Encyclopedia of Aerospace Engineering. John Wiley and Sons, Hoboken 2010.
[9] Bell J.H., Mehta R.D.: Boundary-layer predictions for small low-speed contractions. AIAA J. 27(1989), 3, 372–374.
[10] Noor A., Ed.: Wind Tunnel Designs and their Diverse Engineering Applications. IntechOpen, 2013.
[11] Discetti S., Ianiro A., Aref H.: Experimental Aerodynamics. CRC Press – Taylor & Francis Group; Boca Raton 2017.
[12] Idelchik I.E.: Handbook of Hydraulic Resistance. Coefficients of Local Resistance and of Friction. US Atomic Energy Commission and the National Science Foundation. Washington DC 1966.
[13] Ansys Fluent Fluid Simulation Software https://www.ansys.com/products/fluids/ ansys-fluent (access: 5 Jan. 2020).
[14] Ansys Meshing https://www.ansys.com/products/platform/ansys-meshing (access: 5 Jan. 2020).
[15] Ochrymiuk T.: Numerical analysis of microholes film/effusion cooling effectiveness. J. Therm. Sci. 26(2017), 5, 459–464.
[16] Szwaba R., Ochrymiuk T., Lewandowski T., Czerwinska J.: Experimental investigation of microscale effects in perforated plate aerodynamics. J. Fluids Eng. 135(2013), 12, 121104-1-10
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Authors and Affiliations

Ryszard Szwaba
1
Krzysztof Hinc
1
Tomasz Ochrymiuk
1
Zbigniew Krzemianowski
1
Piotr Doerffer
1
Marcin Kurowski
1

  1. Institute of Fluid Flow Machinery, Polish Academy of Sciences, Fiszera 14, 80-231 Gdansk, Poland
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Abstract

Eurocode standard recommends using fundamental basic wind velocity (characteristic velocity) as the design value in civil engineering. There are different approaches to estimate this value depending on the climate features of the given area and the quality of environmental data. The estimation of the characteristic value requires statistical analysis of historical data regarding wind velocities measured throughout the country at meteorological stations. The results of the analysis are probability density distributions of this random variable for each meteorological station. On this basis, values of characteristic wind velocity with a mean return period of 50 years are determined. The zones with uniform velocities are delineated on the map of the country. In the case of Poland the last evaluation of wind zones took place over 15 years ago. Higher quality of measurement data on the one hand, and the introduction of the second generation of Eurocode standards on the other hand, create a need to check and update these zones. This work presents theoretical basis for the estimation of characteristic values of random variables in the context of wind velocity, comprehensively reviews practical methods used for this purpose and summarizes current situation in Poland, finally discusses the issues related to the heterogeneity of wind data, illustrating them with an example.
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Authors and Affiliations

Tomasz Lipecki
1
ORCID: ORCID
Mariusz Gaczek
2
ORCID: ORCID
Adam Goliger
3
Grzegorz Kimbar
4
ORCID: ORCID
Wojciech Wegrzynski
5
ORCID: ORCID

  1. Lublin University of Technology, Nadbystrzycka 40, 20-618 Lublin, Poland
  2. Poznan University of Technology, Piotrowo 5, 60-965 Poznan, Poland
  3. Firelab, Pretoria, South Africa
  4. Building Research Institute, Filtrowa 1, 00-611 Warszawa, Poland
  5. Building Research Institute, 00-611Warszawa, Poland
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Abstract

On the basis of 35 one-hour series of the measurement of the wind velocity, read out every two minutes, the wind structure at the Arctowski Station, situated on Admiralty Bay, King George Island, was analysed. Very strong turbulence was found with air flow directions from over the area of the Island (S, SW. W and NW) and laminarity with directions from SE, E, NE and partly N, i.e. when the air flows from Admiralty Bay or from over the open waters of Bransfield Strait. The qustiness coefficient, the relationship between the maximum and mean velocities and the intensity of turbulence were determined for the two flow types. Two extremely different cases, in terms of flow character, were considered, by determining for them the distributions of instantaneous velocities and those of oscillations.

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Authors and Affiliations

Dominik Kowalski
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Abstract

Power spectrum techniques were applied to two time series of wind speed values recorded at the Arctowski Station in order to investigate the influence of turbulent and laminar air flow on the quasi-periodicity of the micro-scale wind structure.

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Authors and Affiliations

Ewa Skrzypczak
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Abstract

The analysis of speed and direction distribution of upper wind in the layer up to 3500 m was carried out on the basis of pibal ascents performed over the Admiralty Bay (King George Island, South Shetland Islands).

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Authors and Affiliations

Jolanta Kratke
Danuta Wielbińska
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Abstract

Annoyance ratings for artificially created noises, resembling the main characteristics of temporal wind turbine noise, were studied by means of a listening experiment involving 21 participants with normal hearing. Three types of stimuli were examined: broadband noise (−4 dB/octave), noise generated by moving cars, and narrowband noise. All stimuli had the sound level fluctuations typical for wind turbine noise. The magnitude of the sound level fluctuations was measured in a quantitative way, by using the characteristics of amplitude modulated sound: modulation rate and modulation depth. Our aim was to examine how the modulation rate and the modulation depth influence the noise annoyance assessment of broadband and narrowband amplitude modulated noises. Three different modulation rates, 1, 2 and 4 Hz, and sound level fluctuations (a measure of the modulation depth), 3, 6, 9 dB, were applied to each type of stimuli (with exception of noise generated by the moving cars) and investigated. The participants in the listening experiment were presented with sound stimuli in laboratory conditions and asked to rate their annoyance on a numerical scale. The results have shown a significant difference between the investigated conditions. The effect was particularly strong between the annoyance judgments of different types of noise (narrow and broadband), and modulated versus unmodulated noises. Temporal fluctuations occurring in wind turbine noise are very pertinent to the perception of annoyance and could be responsible for its being a relatively annoying noise source. The obtained results were discussed and compared to the typical modulation rates and level changes that occur in recordings of real wind turbine noise.
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Authors and Affiliations

Honorata Hafke-Dys
Tomasz Kaczmarek
Anna Preis
Adam Biniakowski
Paweł Kleka
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Abstract

The resistance parameters of timber structures decrease with time. It depends on the type of load and timber classes. Strength reduction effects, referred to as creep-rupture effects, due to long term loading at high stress ratio levels are known for many materials. Timber materials are highly affected by this reduction in strength with duration of load. Characteristic values of load duration and load duration factors are calibrated by means of using probabilistic methods. Three damage accumulation models are considered, that is Gerhard [1] model, Barret, Foschi[2] and Foshi Yao [3] models. The reliability is estimated by means of using representative short- and long-term limit states. Time variant reliability aspects are taken into account using a simple representative limit state with time variant strength and simulation of whole life time load processes. The parameters in these models are fitted by the Maximum Likelihood Methods using the data relevant for Polish structural timber. Based on Polish snow data over 45 years from mountain zone in: Zakopane – Tatra, Świeradów – Karkonosze, Lesko – Bieszczady, the snow load process parameters have been estimated. The reliability is evaluated using representative short – and long –term limit states, load duration factor kmod is obtained using the probabilistic model.

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Authors and Affiliations

T. Domański
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Abstract

The thermal, anemometric and bioclimatic conditions on the topoclimatic scale were investigated in the summer season in the EbbaValley region in central Spitsbergen. Eight measurement sites, representing different ecosystems and different types of active surfaces typical of Spitsbergen, were chosen and automatic, hourly recorded, measurements were per− formed at the sites between 11 and 25 of July 2009. The analysis of the spatial distribution of the air temperature and thewind−chill temperature, both for the dayswith radiation and non−ra− diation weather, indicates that the most favorable regions in the interior of Spitsbergen are those situated in the shielded central parts of the valleys and in the lower parts of the slopes with southern exposure. The thermal and wind conditions are definitely less favorable at the tops of elevations and on the glacier. Large differences between the air temperature and the wind−chill temperature were noted, particularly during the unfavorable non−radiation weather, on the glacier and on open peaks due to a large horizontal and vertical wind−chill temperature gradient. The thermal inversions observed in the Ebba Valley in July 2009 were not of the typi− cal, glacier katabatic wind origin. They appeared during the western air circulation, which brings advection of cooled air from above the cold waters of Petunia Bay. The cold air pene− trates into the valley and pushes upwards themass of warmer air in the valley, creating a rather thin inversion layer, whose upper edge is marked with thin Stratus clouds.
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Authors and Affiliations

Ewa Bednorz
Leszek Kolendowicz
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Abstract

By means of small wind turbines, it is possible to create distributed sources of electricity useful in areas with good wind conditions. Sometimes, however, it is possible to use small wind turbines also in areas characterized by lower average wind speeds during the year. At the small wind turbine design stage, various types of technical solutions to increase the speed of the wind stream, as well as to optimally orientate it, can be applied. The methods for increasing the efficiency of wind energy conversion into electricity in the case of a wind turbine include: the use of a diffuser shielding the turbine rotor and the optimization of blades mounted on the turbine rotor. In the paper, the influence of the diffuser and rotor blades geometry on the efficiency of an exemplary wind turbine for exploitation in the West Pomeranian Province is investigated. The analyses are performed for three types of the diffuser and for three types of rotor blades. Based on them, the most optimal shapes of the diffuser and blades are selected due to the efficiency of the wind turbine. For the turbine with the designed diffuser, calculations of the output power for the assumed different values of the average annual wind speed and the constant Betz power factor and the specified generator efficiency are made. In all the analyzed cases, the amount of energy that can be generated by the turbine during the year is also estimated. Important practical conclusions are formulated on the basis of these calculations. In the final part of the paper, a 3D model of the wind turbine with the diffuser and rotor blades chosen based on earlier analyses is presented. As a material for the diffuser and rotor blades, glass fiber type A is applied. By means of calculations using the finite element method, the limit displacement of the turbine structure under the influence of a hurricane wind are determined. Based on these calculations, the correctness of the modelled small wind turbine structure has been demonstrated.

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Authors and Affiliations

Kamil Krzysztof Skorupa
Rafał Grzejda
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Abstract

This article considers designing of a renewable electrical power generation system for self-contained homes away from conventional grids. A model based on a technique for the analysis and evaluation of two solar and wind energy sources, electrochemical storage and charging of a housing area is introduced into a simulation and calculation program that aims to decide, based on the optimized results, on electrical energy production system coupled or separated from the two sources mentioned above that must be able to ensure a continuous energy balance at any time of the day. Such system is the most cost-effective among the systems found. The wind system adopted in the study is of the low starting speed that meets the criteria of low winds in the selected region under study unlike the adequate solar resource, which will lead to an examination of its feasibility and profitability to compensate for the inactivity of photovoltaic panels in periods of no sunlight. That is a system with fewer photovoltaic panels and storage batteries whereby these should return a full day of autonomy. Two configurations are selected and discussed. The first is composed of photovoltaic panels and storage batteries and the other includes the addition of a wind system in combination with the photovoltaic system with storage but at a higher investment cost than the first. Consequently, this result proves that is preferable to opt for a purely photovoltaic system supported by the storage in this type of site and invalidates the interest of adding micro wind turbines adapted to sites with low wind resources.

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Authors and Affiliations

Mohammed Salim Hadjidj
Nacereddine Bibi-Triki
Faouzi Didi
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Abstract

International scales describing the intensity of tornadoes are investigated along with reports from the Polish Government Security Centre on all types of wind storms in Poland. Then, collected tornado reports for the years 1899–2019 in Poland, a set of the annual maximum gust wind speeds measured at 39 meteorological stations from 1971 to 2005 (35 years), descriptions of Poland’s strongest wind storms in the 21st century, estimating the risk of significant strong and extreme winds in Poland, and classification of maximum wind speeds by Lorenc (2012) are presented. Based on these data, i.e. measured and estimated wind speeds, this paper proposes two separate intensity scales to categorize synoptic, thunderstorm, and downslope winds (in the Tatra and Karkonosze regions), derechos, tornadoes, and downbursts, i.e. all types of wind storms. These scales are simpler than the one put forward by Lorenc (2012). These two scales cover a range of maximum wind speeds from 20 to 90 m/s. This proposal is only applicable to Poland. Other countries may determine whether it applies to them.

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Authors and Affiliations

Tadeusz Chmielewski
Henryk Nowak

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