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EN
The paper describes a system of steam boilers with the main attention drawn to the selected aspects of their operations in municipal district heating. The presented fuel characteristics show the characteristic factors in the described processes. The analysis reflects the simulations of fuel mixtures and their results in relation to the energy conversion processes in environmental aspects. Some considerations underline the results that have influence on the decisions pertaining to mixture composition. The paper presents comparative graphs and results in absolute terms. The conclusions are formulated taking into account the environmental effects, in particular localization of system elements and addresses the possible solution options to improve fuel mixtures and develop system efficiency.
PL
W pracy omówiono podstawowe zagadnienia dotyczące modelowania sprzężonych procesów pochłaniania i konwersji energii promieniowania słonecznego na energię cieplną i elektryczną. W przedstawionych modelach zdefmiowanych dla trzech typów ogniw fotowoltaicznych uwzględniono zarówno parametry optyczno-geometryczne modułu jak i charakterystyki prądowo-napięciowe ogniwa. Symulacje komputerowe wykonano przy pomocy programu ESP-r dla dwóch wybranych okresów Typowego Roku Meteorologicznego; tygodnia lata i zimy odpowiednio o największej i najmniejszej ilości promieniowania słonecznego. Dodatkowo dla potrzeb analiz energetycznych symulacje przeprowadzono dla pełnego roku kalendarzowego. W obliczeniach uwzględniono zarówno zmianę promieniowania bezpośredniego i rozproszonego jak i zmianę temperatury otoczenia wpływającej bezpośrednio na wydajność ogniw fotowoltaicznych.
EN
The proper designing of PV systems requires the use of suitable equipment for building energy simulation. It enables to design the best position of the PV array, as well as the right quantity of produced energy in different cases. Modelling building integrated photovoltaic (PV) in building energy simulation are complex and required advanced numerical techniques. The PV responds to many environmental influences like: irradiance level, its spectral distribution, temperature and electrical characterisation of PV modules. Modelling of three single PV array in ESP-r is presented in t his paper. Computer simulations have been carried out with the use of TMY data for Warsaw, taking into consideration direct and diffuse solar radiation and temperature. The amount of energy produced by PV array during the whole year, as well as the change ofpower output within selected summer and winter weeks, have been calculated.
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Content available remote Absorpcja energii elektromagnetycznej przez ekrany magnetyczne
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Efektywne ekranowanie urządzeń prowadzi do znacznego zmniejszenia natężeń pola elektrycznego i magnetycznego i jest najczęściej realizowane poprzez przegrody przewodzące różnie interferujące składowe fali elektromagnetycznej na powierzchniach granicznych. Wspólną cechą obu rodzajów ekranowania jest ograniczanie obszaru oddziaływania energii poprzez jej pochłanianie w ekranach magnetycznych. Struktura i materiał ekranu decydują o wartości tej energii, która zamieniana w ciepło może prowadzić do lokalnych przegrzań. Ograniczanie mocy w ekranach staje się istotniejsze, gdy stanowią one elementy obudów, osłon czy konstrukcji urządzeń generujących zakłócenia elektromagnetyczne a nie chronią jedynie aparaturę przed wpływem obcych pól.
EN
An effective shielding of devices leads to significant reduction of the electric and magnetic fields intensity. Most frequently the shielding is realized by barriers conducting different components of the electromagnetic waves which interferences on the boundary surfaces. The common feature of the both kinds of shielding is the limitation of the interaction range by the energy absorption in the magnetic shields. The range of the energy is determined by the structure and material of the shields. The transfer of the absorbed energy into heat, which process occurs in the shields leads to the shield heating. Limitation of the power generated in the shields becomes more important when the shields are the housing elements of the devices, then there are used only for protection against external electromagnetic fields.
EN
Solar spectral irradiance covers a fairly broad wavelength range. Solar radiation is part of the electromagnetic spectrum which is described by the concept of wave-particle duality. The corpuscular theory of electromagnetic radiation states that energy is transmitted by photons. Photons carry specific amounts of energy which can be used to convert solar energy into other types of energy, in particular electricity. The internal photoelectric effect is important for the conversion of solar energy to electricity because the efficiency of the external photoelectric effect is too low. Every quantum of solar energy also carries a certain amount of energy which can be converted into heat energy. The objective of the paper is to analyze and compare the efficiency of solar energy conversion in photon and thermal processes, to review the technological advances made in this field, and to indicate potential directions for the development of systems converting solar energy to electricity.
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Many countries worldwide support green energy production on large scale mostly by solar or wind energy subsidizing manufacture and operation of such systems. During the last two decades, there has been significant increase in wind energy production globally. Statistics show continuously growing investments in the development and installation of wind turbines and farms. Currently, wind energy is the second most important source of renewable energy after water energy. By 2016 global cumulative installed wind capacity surpassed 432 k MW [GWEC]. In last several years, most dynamic growth in wind power generation investments was recorded in Asia. Europe, in comparison, has less impressive but steady growth in wind power plants through the years. In this article, authors present global demand on energy in comparison to efficiency of wind power plants in relation to the local and global location as well as to the scale of installed system. Authors also present statistical data concerning wind power plants development. General classification, using number of criteria (ex. power output, construction size, rotor axis orientation and other) of wind to electric power converting devices is presented. Various types of devices, which authors describe in this article, can perform conversion of wind blow energy to the electric energy using different yet similar methods.
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Content available remote The effect of the incidence angle modifier on the efficiency of solar collectors
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The article addresses the effect o f a varying factor, called the incidence angle modifier, on the efficiency related to the gross solar collector surface area, achievable during the day. On the basis of the adopted assumptions defining the operating conditions of solar collectors, their averaged efficiencies of solar radiation energy conversion has been calculated. The proposed calculation method makes it possible to prepare a more complete thermal characteristic and to more precisely estimate the energy output of a solar collector under real conditions.
EN
Regenerative braking in electric or hybrid driven vehicles is now commonly used feature. Development of technologies of electrical machines, secondary energy sources, power electronics and control systems allows for more efficient using of this attribute. Regenerative braking system converts the kinetic energy of moving vehicles on this form of energy that you can store in a secondary source of energy. The most common form of energy after conversion is electricity, easy to store in batteries or supercapacitors. There also are known systems with storage of mechanical energy (high-speed flywheels with composite rotors). Drive systems with optional regenerative braking should take into account a number of aspects influencing the process. It is very important to maintain the stability of the vehicle movement during braking. Another important aspect is the cooperation of regenerative braking system with conventional, mechanical brake system of the vehicle driven by a single axis. Sizing of the electrical machine (or machines) is associated with the needs of the propulsion of the vehicle, which limits the amount of absorbed energy in the initial stage of braking. Individual elements of the system energy conversion efficiency chain complexity affect the energetic results of this process. On the energy, efficiency of the process of braking energy recovery affects string conversion efficiency in the individual components of the system. Regenerative braking is the important factor, which could improve electric vehicle market chances, particularly in the city or neighbourhood personal transport. The article contains a description of the technical and legal circumstances of the process of regenerative braking and energy aspects of this process.
EN
The paper presents the results of a study regarding the scrap tire to energy conversion using two different processes: combustion and pyro-combustion. Laboratory determinations were conducted on two different scrap tires (summer and winter) to assess the primary, ultimate and calorimetry analysis of the feedstock. Pyrolysis experiments data achieved on laboratory scale batch reactors, under a controlled inert atmosphere using nitrogen, were used in the study. Using the experimental data on the reaction products distribution, chemical composition and the specific energy content, the waste to energy conversion chain using combustion was analyzed. The direct combustion of the waste was compared to the combustion of pyrolysis reaction products with respect to the specific mass and energy flows. Based on experimental data the process energy balance was computed.
PL
W artykule przeprowadzono analizę dynamiki wzrostu sprawności konwersji promieniowania słonecznego na energię elektryczną, obejmującą lata 1997–2016, dla wybranych ogniw i modułów fotowoltaicznych. Przedstawiono obowiązujące procedury i standardy pomiarowe. Postęp sprawności sklasyfikowanych w grupy ogniw i modułów zilustrowano graficznie, przeprowadzono dyskusję wyników.
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This paper presents solar radiation conversion efficiency progress into electricity for selected photovoltaic cells and modules since 1997 till 2016. Described the existing procedures and measurement standards. Efficiency progress classified in a groups of cells and modules shows in the form of charts and discused results.
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Content available Utilising water wave energy – technology profile
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The use of wave energy was studied at the Maritime University of Szczecin. The two main subjects were wave-energy conversion and using wave energy to protect the seashore against the hazardous effects of extreme waves. A construction of new technologies were outlined. Future research and intended cooperation were presented.
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Content available Energy – conversion, conservation and management
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Energy is an abstract notion that helps to understand the nature and contributes to the creation of the civilization. The energy notion has a huge meaning not only due to practical reason – it is essential for economy and philosophy too. It turns out that in Hellenic philosophy, and especially in its fundamental part, i.e., metaphysics, there is no place for the concepts and methods of reasoning developed by physics and chemistry. Philosophy assumes that most of the physical and chemical concepts are not known in nature in spe these are employed by science only as a kind of mental keys (qualitative occultea) for the description and understanding of the universe. The concept of energy is only one example of a notion accepted both by the philosophers (in its metaphysical sense) and physicians (in its descriptive role).
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In the paper the impact of changes in coal quality on boiler operation with the retort furnace had been discussed. Study used a test for the three types of coal from different mines. Energy and emission studies have shown that even relatively coals not much different with physicochemical parameters, causing a marked change of the efficiency of device operation. Attention was drawn to the growing scale of the problem in the application of fuel significantly deviating from properties of the classical fuel to the retort furnaces. The ways to improve the quality of use of boilers with retort burner have been given.
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Content available remote Potencjalne możliwości wykorzystania energii słonecznej w budownictwie
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Przedstawiono potencjalne możliwości wykorzystania promieniowania słonecznego, jako źródła energii w budownictwie. Szczególną uwagę zwrócono na zdolności absorpcyjne i emisyjne różnych materiałów używanych do przetwarzania energii słonecznej. Wskazano praktyczne kierunki dotyczące zastosowania odpowiednich konstrukcji i materiałów do przetwarzania energii słonecznej. Przedstawiono także niektóre praktyczne urządzenia wykorzystujące w budownictwie promieniowanie słoneczne do ogrzewania budynku oraz ciepłej wody użytkowej.
EN
The possibilities of utilization of solar energy radiation as a source of energy in building systems are discussed. Special attention was focused on absorption and emission properties of a different materials using to solar energy conversion. It was shown the directions of possible developing the solar energy systems about its construction and properties of using materials. A some practical systems for solar energy conversion in building apartment house for warming and hot water preparation are presented.
EN
This work presents a theoretical study for the distribution of nanocomposite structure of plasmonic thin-film solar cells through the absorber layers. It can be reduced the material consumption and the cost of solar cell. Adding nanometallic fillers in the absorber layer has been improved optical, electrical characteristics and efficiency of traditional thin film solar cells (ITO /CdS/PbS/Al and SnO2/CdS/CdTe/Cu) models that using sub micro absorber layer. Also, this paper explains analysis of J-V, P-V and external quantum efficiency characteristics for nanocomposites thin film solar cell performance. Also, this paper presents the effect of increasing the concentration of nanofillers on the absorption, energy band gap and electron-hole generation rate of absorber layers and the effect of volume fraction on the energy conversion efficiency, fill factor, space charge region of the nanocomposites solar cells.
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Content available remote Elektrownie wiatrowe – krótki przegląd właściwości i zastosowań
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PL
Omówiono właściwości najczęściej stosowanych w elektrowniach wiatrowych generatorów asynchronicznych, synchronicznych, prądu stałego i maszyny dwustronnie zasilanej. Przedstawiono właściwości i wymagania dotyczące generatorów i układów sprzęgających w zależności od mocy i przeznaczenie – jako samodzielne, niezależne źródła energii lub jako źródła współpracujące z systemem sieci energetycznej.
EN
The features of most commonly used wind power generators asynchronous, synchronous, DC as well as double fed one are discussed. Characteristics and requirements for these generators and power electronics are presented as well as theirs depending on the power and purpose. A standalone, independent energy systems and grid system are shown.
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Content available The grate furnace with top-dawn burning
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EN
In the article has been discussed the principle operation of the furnace with constant grate and with top-down burning solid fuel furnace charge. The characteristic reaction zone of the bottom-up burning layer were chosen and described. The solution was confronted with a traditional grate with bottom-up combustion of fuel layer. For bough cases the typical characteristics of heat-emission were used. The real constructional solution of the water boiler with constant grid, in which is implemented top-down technique combustion of pit-coal, is presented. The construction of the boiler and the principle of its operation were talked over. Due to the specific work of this device, is demonstrated that the proper operation, of this type of equipment, is required by qualified personnel. Otherwise, the boiler can be operated as traditional energy appliance with constant furnace and top-down burning.
PL
W pracy omówiono zasadę działania paleniska z rusztem stałym i z odgórnym spalaniem wsadu paliwa stałego. Wytypowano oraz opisano charakterystyczne strefy reakcyjne w warstwie zasypowej. Rozwiązanie skonfrontowano z tradycyjnym paleniskiem rusztowym ze spalaniem oddolnym warstwy paliwa. Posłużono się typowymi charakterystykami cieplnoemisyjnymi dla obu przypadków. Zaprezentowano rzeczywiste rozwiązanie konstrukcyjne kotła wodnego z rusztem stałym, w którym realizowana jest odgórna technika spalania węgla kamiennego. Omówiono budowę kotła oraz zasady jego eksploatacji. Z uwagi na specyfikę pracy urządzenia wykazano, że do prawidłowej obsługi tego typu urządzeń wymagany jest fachowy personel. W przeciwnym razie kocioł może być eksploatowany jak tradycyjne urządzenie energetyczne z rusztem stałym i oddolnym spalaniem.
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Content available remote Otrzymywanie i właściwości CoSb3 domieszkowanego Ag
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PL
Przedmiotem pracy były badania wpływu domieszki Ag na wartość współczynnika efektywności termoelektrycznej, ZT, trójantymonku kobaltu CoSb3. W tym celu przygotowano serię próbek o składach nominalnych AgxCo8Sb24, gdzie x = 0-0,5. Badania strukturalne oraz składu fazowego wykonano za pomocą dyfrakcji rentgenowskiej XRD. Zbadano wpływ domieszki na przewodnictwo elektryczne, współczynnik Seebecka oraz przewodnictwo cieplne otrzymanych materiałów w zakresie temperatur od 300 do 560K. Na podstawie uzyskanych wyników wyznaczono zależności współczynnika efektywności termoelektrycznej, ZT, od temperatury.
EN
The aim of this work was to examine the influence of Ag additive on thermoelectric figure of merit, ZT, of cobalt triantimonide CoSb3. A series of samples with nominal composition of AgxCo8Sb24, (x = 0-0,5) was prepared. Structural properties and phase composition was analyzed by XRD diffraction method. The influence of Ag content on electrical conductivity, Seebeck coefficient, thermal conductivity and crystal structure parameter was investigated. The temperature dependence of thermoelectric figure of merit, ZT, was determined using measured thermal and electrical parameters.
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Przedmiotem pracy jest opracowanie złącz kontaktowych pomiędzy półprzewodnikowym materiałem termoelektrycznym CoSb3, a elektrodą miedzianą oraz dobór odpowiednich warstw ochronnych hamujących procesy dyfuzji na granicy złącz. Złącza CoSb3/Cu wytwarzane były techniką lutowania rezystancyjnego w atmosferze gazów ochronnych (90% Ar + 10% H2) z użyciem lutów Ag-Cu. Bariery dyfuzyjne (Ni, Mo, Cr80Si20) nanoszono metodą rozpylania magnetronowego na elementy wykonane z polikrystalicznego CoSb3. Mikrostrukturę oraz skład chemiczny złącz badano za pomocą elektronowego mikroskopu skaningowego (SEM) z rentgenowskim analizatorem dyspersji energii EDX. Badania parametrów elektrycznych złącz kontaktowych takich jak rezystancja, charakterystyki prąd-napięcie, wykonano na specjalnie przygotowanym do tego celu stanowisku pomiarowym. Przeprowadzono pomiary współczynników rozszerzalności cieplnej materiału termoelektrycznego oraz lutowia.
EN
The goal of the present work was to develop the junctions between CoSb3 semiconducting thermoelectric material and a copper electrode,as well as the selection of appropriate protective layers, which inhibit diffusion processes at a junctions area. The CoSb3/Cu junctions were formed by resistance soldering technique in the protective atmosphere of 90% Ar + 10% H2, using Ag-Cu based solders. Diffusion layers (Ni, Mo, Cr80Si20) were prepared by magnetron sputtering technique and deposited on polycrystalline element made of CoSb3. The microstructural properties and chemical compositions of the junction area were analyzed by a scanning electron microscope (SEM) equipped with energy-dispersive X-ray analyzer (EDX). Measurements of electrical properties of the junctions such as resistance and current–voltage characteristics were performed on an apparatus designed especially for this purpose. Thermal expansion coefficients of the thermoelectric material and the solder were also characterized.
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Content available remote Stanowisko do badań turbin małej mocy dla energetyki rozproszonej
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PL
W pracy przedstawiono zasadnicze parametry i możliwości stoiska do badań turbin małej mocy przeznaczonych dla energetyki rozproszonej. Opisano techniki pomiarowe dla wyznaczenia charakterystyk zewnętrznych oraz przedstawiono możliwości zaawansowanych badań trójwymiarowego przepływu. Przedstawiono przykładowe wyniki badań.
EN
Recently, increased attention has been paid to small gas turbine nits for electricity and heat generation. The new technologies must be highly flexible for varying electricity and heat supply, high fuel utilization, reliability and security. The paper describes test rig and preliminary investigations of turbine components for distributed power generation.
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In the paper a quality analyzer of energy conversion in power electronics systems is presented. That solution is based on programmable system, equipped with floating point DSP processor ADSP-21262 type (Analog Devices Inc.) and virtual instrument elaborated with aid of National Instruments LabVIEW environment. The chosen algorithms structures of elaborated virtual device are described. Chosen results of experimental researches are presented also.
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