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Content available remote LiBr-H20 absorption cycle design for whole year use in medium climate conditions
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EN
In the paper a new LiBr-H20 sorption system for the whole year use in medium European conditions has been presented. Thermodynamics of the system has been simulated for the steady state conditions, using realistic efficiency factors for each exchanger. The simulation has been done for each characteristic period of the year. Also the heat exchangers surfaces have been estimated using cautiously selected formulas. Finally the economic of the designed system has been calculated as well as the environmental effects. The conclusion is that the use of such a system has to be encouraged by tax system since the environmental effects are very promising, but the investment costs are high.
EN
The pressing need for reducing the global warming effects from the emission of greenhouse gases necessitates the use of renewable energy where possible. Solar distillers are devices with a promising future. In this work, an experimental setup (solar distiller) was constructed and equipped with a mirror, basin, glass cover, compressor, sensors and controllers to study the partial evacuation effects on different solar distillation parameters and the production capacity under the Jordanian climate. The test rig was tested for three different water levels (1, 2 and 3 cm), and four pressure values (1, 0.9, 0.8 and 0.7 atm) under the Jordanian climate. The detailed experimental results strongly correlate with the results previously published in literature. The modifications performed on the system doubled the previously attained efficiency. These improvements in the solar distiller will favor the application of the vacuum pressure principle in many different applications, such as the water extraction from the atmospheric air.
EN
The worldwide transition to a future with net-zero emissions depends heavily on solar energy. However, when land prices rise, and population density rises, the need for large land expanses to develop solar farms poses difficulties. Floating Photovoltaics (FPV) has come to light as a viable remedy to this problem. FPV, which includes mounting solar panels on bodies of water, is gaining popularity as a practical choice in many nations worldwide. A significant capacity of 404 GWp for producing clean energy might be attained by using FPV to cover only 1% of the world’s reservoirs. This review shows that FPV has several benefits over conventional ground-mounted PV systems. On the other hand, there is a large study void regarding the effects of FPV on water quality and aquatic ecosystems. This review looks at the most recent FPV research, including its advantages, disadvantages, and potential. It looks into the compatibility of various bodies of water, worldwide potential, system effectiveness, and the possibility of integrating different technologies with FPV.
EN
Solar energy constitutes superior renewable source due to its availability, natural distribution and no necessity for transportation. It can be designed to fulfill the requirements of power demands, and can work in synchronization with battery banks and diesel generators or any other power source to provide a continuous and stable power. Solar energy is already one of the best solutions to fulfill power demands. A solar thermal collector is a key element for the collection and conversion of solar energy into thermal energy. There are different types of solar collectors, the most important one is the conventional 'Flat-Plate' kind, which absorbs the incident radiation and converts it to thermal energy. The main objective of this work is to study the effect of Titanium Oxide (TiO2) and Zinc Oxide (ZnO) water-based nanofluids on the performance of solar flat plate collector. In order to achieve this objective, three identical flat plat solar collectors were used with appropriate instrumentations necessary to experimentally calculate their performance. The working fluid in the first collector was pure water, while in the second collector, it was Titanium Oxide water-based nanofluid and in the third one – Zinc Oxide water-based nanofluid. Two different values of volume fraction of both oxides were used as well. It was found that the addition of Titanium Oxide and Zinc Oxide nanoparticles leads to an increase in the efficiency of the solar collector. The efficiency of the collector was found to be maximum over all values of (Tin – Tamb) when a 0.2% volume fraction of Titanium Oxide was used with a maximum efficiency of 40%, followed by the case of 0.6% volume fraction of Titanium Oxide. Furthermore, zinc oxide caused a maximum improvement in the performance of solar flat plate collector when 0.6% was used, followed by 0.2% concentration. Finally, it was found that titanium oxide is characterized by more pronounced improvement in the performance of solar flat plate collector.
EN
The paper presents an algorithm of optimal choice of velocity of a car supplied from photovoltaic panels with a view to attain its maximum range. In case the power supplied from the panel exceeds the vehicle demand, the surplus is directed to the battery, otherwise the power us drawn from it. The consideration takes into account geographical location, duration of the travel (according to the season of the year and time of the day), the effect of construction and technological parameters of the vehicle, efficiency and surface area of the photovoltaic panel, and efficiency of the driving motor. The lead acid and lithium-ion batteries have been used. Analysis and computer simulation have been carried out for a trial run of a car supplied with solar power with a view to attain its maximum range. The location of Warsaw has been assumed, in the months of high solar irradiation. The vehicles of various parameters, photovoltaic cells of various efficiencies and surface area, driving motors of various efficiencies, the lead-acid and lithium-ion batteries have been assumed.
PL
Przeanalizowano możliwość wykorzystania energii słonecznej do podgrzania c.w.u. Obiektem badań był WSS im. NMP w Częstochowie. Przedstawiono wyniki badań instalacji kolektorów słonecznych będących wyposażeniem szpitala. Instalacja ta wspomaga przygotowanie c.w.u. Badania dotyczyły wpływu zmienności promieniowania słonecznego, w ciągu roku i doby, na sprawność instalacji.
EN
The possibility of using solar energy for heating of usable hot water (uhw) has been analysed. The object under test was Our Lady Specialist Hospital in Częstochowa. The results of investigations of solar installations in the hospital have been presented. The installation supports the preparation of uhw. The investigations concerned the influence of solar variability during the year and day on installation efficiency.
EN
One of the methods leading to C02 reduction in Poland is the substitution of fossil fuels by renewable energy sources. Direct use of energy from renewable energy sources causes a significant reduction in Greenhouse Gases (GHGs) emissions to the atmosphere. Photovoltaic (PV) systems generating electricity from solar radiation are foreseen as a technological option significantly contributing to the sustainable energy supply due to continuous technological progress and drastic cost reduction. In this paper the progress that has been made all around the world in the last years and work that needs to be done, especially in the European countries and in Poland was presented. Poland should follow the example of the industrially developed world, where investments in PV systems continue to grow, with most interest focused on the great potential for PV in human settlements. The photovoltaic technology offers many social and economic benefits for users in Poland. The author points out the need to create a long-term strategy for implementing PV systems and neces sary changes in the legislation system. The photovoltaic potential of our region from the geographical location point of view has been presented.
EN
The article describes a newly developed calculation technique and the choice of the geometrical parameters of the solar collector with the siphon effect. The dependence of the cross section of the pipe on the flow time for different values of the head is also shown. With an increase in the siphon head, the flow time of the liquid increases as well. This is explained by the fact that with increasing head, the hydraulic resistance of the siphon rises, which leads to a decrease in the velocity of the fluid. For the first time, a relationship determining the time of fluid outflow in dependence on the geometric parameters of the solar collector is formulated. The developed technique allowed to establish that the local hydraulic resistance and friction play a significant role in the heat carrier flow rate.
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Content available Zasady kształtowania budynków pasywnych
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PL
W artykule przeprowadzono analizę wpływu pojemności cieplnej pomieszczenia oraz wielkości południowego przeszklenia na warunki tenniczne we wnętrzu budynku pasywnego. Stwierdzono, że optymalna powierzchnia okna jest w polskich warunkach klimatycznych nieduża i silnie zależna od właściwości obudowy, natomiast jej przewymiarowanie skutkuje znacznym wzrostem zapotrzebowania zarówno na ogrzewanie jaki i na chłodzenie. Zaproponowano, aby proces racjonalnego projektowania architektonicznego uwzględniał charakterystykę cieplną budynku przy podejmowaniu decyzji dotyczących wielkości przeszklenia.
EN
Results of the long-tenn influence of the beat accumulation properties and south window area on the passive solar building heating energy demand and the thennal comfort has been analyzed. It was found that the optimum window area is relatively smalI and strongly connected to the building shell properties. Oversized window area results in large increase of the heating and cooling demand. Thennal capacity of the space is not very important in case of the well-designed building but maybe crucial in case of the oversized windows. It was suggested to link, in reasonable architectural design, window area with general building thennal profile.
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Humans, like every other living organism, are dependant on solar energy. If solar energy is to be used consciously, whether directly or stored, there is a need for precise assessment. The bigger the accuracy of the assessment, the greater the benefits of the application of solar energy will be. The simplicity and ease of application of a tool for such predictions would lead to solar energy resources assessment on a large scale. This would result in greater awareness of the potential of the sun energy and application of the solar energy on a larger scale, with all the benefits of using renewable energy resources.
PL
Artykuł poświęcony regulacji przepływu pośredniego nośnika ciepła (płynu solarnego) w instalacji kolektora słonecznego. W części pierwszej tej publikacji ( „TCHK”, nr 3/2010, s. 88) zwrócono uwagę na wpływ prawidłowego przepływu tego płynu na sprawność kolektora i osiągany w nim przyrost temperatury nośnika ciepła. Sporo uwagi poświęcono nie domaganiom występującym w pracy instalacji solarnej. W pierwszej kolejności dotyczącym zbyt małego przepływu płynu solarnego ze wskazaniem negatywnych konsekwencji zaistnienia takiej sytuacji. W podobnej konwencji omówiono problem zbyt dużego przepływu płynu solarnego. Część druga tej publikacji poświęcona jest istotnemu zagadnieniu sygnału wykorzystywanego do uruchomienia pompy obiegowej instalacji solarnej, którym jest odpowiednia różnica temperatur, jaka musi zaistnieć podczas pracy kolektorów słonecznych. Autor rozważa dwa przypadki; zbyt dużej i zbyt małej różnicy załączeniowej, i wynikającym z tych sytuacji konsekwencjom
EN
This paper deals with the problem of control of heat-transfer fluid flow in solar heating systems. The influence of this flow on efficiency and thermal effect in solar collectors has been described in the first part ("TCHK" nr 3/2010 p.88). Malfunctions of solar systems due to insufficient or excessive solar fluid flow have also been mentioned. The second part deals with an importantproblem of proper signal used to swich the pump of solar fluid on. This signal is the temperature difference during operation of solar collectors. The consequences of too high and too low switch-on temperature difference are discussed.
PL
W artykule przedstawiono przegląd materiałów wykorzystywanych w energetyce słonecznej z punktu widzenia badań i analiz materiałów nad ich własnościami, które sprzyjają pozyskiwaniu tej formy energii. Omówione zostały materiały z takich grup jak szkła, polimery, metale i gazy. Zakres zastosowań, który został objęty niniejszym opisem zawiera zarówno termiczne kolektory słoneczne, elementy systemów biernych oraz ogniwa fotowoltaiczne. Szczególną uwagę poświęcono rezultatom badań nad materiałami w postaci warstw cienkich oraz struktur wielowarstwowych z nich złożonych, takich jak inteligentne okna, elewacje fotowoltaiczne czy ściany słoneczne. Ponadto przedstawiono zagadnienia badawcze dla struktur wielowarstwowych stosowanych w budownictwie wykorzystujących izolacje przezroczyste i półprzezroczyste w oparciu o badania autorskie prowadzone na Politechnice Lubelskiej.
EN
The paper defines and describes factors and properties of so called solar materials divided into the following groups: glasses, polymers, metals and gases. The applications aspects have been discussed in most of solar energy conversion forms and devices, i.e.: thermal collectors, photovoltaic cells, thermal passive elements, however, excluding conversion in biological materials because this field deserves separate scientific paper. Some special attention has been paid to thin film materials and laminar systems composed of them. This paragraph describes numerous aspects of applications including the ones emerging in smart windows and photovoltaic elevations. Moreover, the problems of solar walls incorporating TIM elements have been described with the help of the author’s research.
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Content available The catamarans George and Energa Solar
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EN
Since a few years students of the Faculty of Ocean Engineering and Ship Technology, Gdansk University of Technology , have designed and built untypical floating units. Until last year their efforts were focused mainly on leg-driven boats. The boats of interesting design have taken part in yearly competitions : the International Waterbike Regatta. Their advanced design made it possible to compete with the best boats from Croatia, Holland, Germany, Turkey and Italy. Recently the students have designed and built a solarenergy-driven boat. It is the catamaran Energa Solar which took part in a prestigious regatta : the Frisian Nuon Solar Challenge carried out in Holland in summer 2006.
PL
W artykule przedstawiono analizę teoretyczną sezonowego zasobnika energii cieplnej pozyskanej ze Słońca (ang. Seasonal Thermal Energy Storage—STES) do pokrywania zapotrzebowania na ciepło zespołu czterech budynków. Zasobnik umieszczony jest w ziemi i podłączony do paneli słonecznych oraz sieci ciepłowniczej łączącej poszczególne bu-dynki. Analizie poddano kilka wybranych przypadków w celu określenia możliwie optymalnych parametrów konstrukcyj-nych całego układu STES (objętość zasobnika i powierzchnia kolektorów słonecznych). W wyniku przeprowadzonych analiz wynika, iż zastosowanie STES-a pozwala zaspokoić potrzeby grzewcze w zakresie 22–100% w zależności od zastosowanego rozwiązania konstrukcyjnego.
EN
This paper presents a theoretical analysis of the seasonal storage of heat gained from the sun (called Seasonal Thermal Energy StorageSTES) to cover the heat demand team of four buildings. The tank is placed in the ground and connected to the solar panels and heat network connecting the various buildings. We analyzed a number of selected cases in order to determine the possible optimal design parameters of the entire system STES (tank volume and collector area). The analyzes show that the use of STES can satisfy the heating needs in 22-100% depending on the applied design solution.
EN
Data on the planetary albedo which were registered in Channel 0.4 - 1.1 mum (VIS) by the geostationary satellite METEOSAT were used to determine a quantitative characteristic of a cloud cover over the Baltic Sea area. By applying the obtained results and the input data generated by the model of the Interdisciplinary Centre for Mathematical and Computational Modelling of the Warsaw University, calculations of irradiance on the sea surface were done using the model of radiation transmission in the Baltic Sea atmosphere. The results were compared to the actinometric data that were continuously recorded by the Gdansk Maritime Institute's measuring buoy that was anchored at 18°31.094'E and 54°56.157'N. It was noted that the application of ICM model information on the atmosphere to the solar radiation transmission model results in decreasing the calculated irradiance values by approximately 15% in relation to the measured values. If cloud cover data in the input data set are replaced by relevant satellite data, then the average difference between the measured data and the modelled ones decreases to approximately 5%.
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A simple spectral model of solar energy input to the sea surface was extended to incorporate space-borne data. The extension involved finding a method of determining aerosol optical thickness (on the basis of AVHRR data) and the influence of cloudiness (on the basis of METEOSAT data) on the solar energy flux. The algorithm for satellite data assimilation involves the analysis of satellite images from the point of view of cloud identification and their classification with respect to light transmission. Solar energy input values measured at the Earth's surface by traditional methods were used to calibrate and validate the model. Preliminary evaluation of the results indicates a substantial improvement in the accuracy of estimates of solar energy input to the sea surface in relation to models utilising only traditionally obtained data on the state of the atmosphere.
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Content available remote Photovoltaics in the World
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EN
The paper describes the status of photovoltaics (PV) in the World. The recent development of PV market and factors influencing its rapid growth are described. The prospects for further growth are analysed. The amount of installed power, production, and current efficiencies invarious technologies are presented. The current status and prospects of bulk and thin-film technologies are described. High efficiency cells and new concepts of solar cells are presented.
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This paper presents an up-to-date overview of the theoretical and technical aspects of thermo-chemical energy conversion (TCEC) systems of concentrated solar energy. The conventional methods of thermal energy conversion and TCEC systems are presented and their merits and demerits are summarized. The different types of TCEC systems and the main elements of the TCEC system are described. Problems associated with the application of these systems, with special emphasis on the receiver/reactor system, are discussed. The industrial importance of the TCEC process is also demonstrated. The state of the art and problems associated with the mathematical and experimental modeling of the TCEC process have also been discussed in more detail. Finally, suggestions as to further development of mathematical and experimental modeling of the TCEC process of concentrated solar energy are presented.
PL
W pracy przedstawiono przegląd teoretycznych i technicznych aspektów termochemicznej konwersji energii skoncentrowanego promieniowania słonecznego (TCEC). Omówiono i porównano klasyczne metody konwersji energii promieniowania słonecznego oraz układy oparte na TCEC. Opisano różne typy układów TCEC oraz ich poszczególne elementy składowe. Przedyskutowano różne problemy związane z zastosowaniem tych systemów ze szczególnym uwzględnieniem układu odbiornik promieniowania/reaktor chemiczny. Wskazano na potencjalne znaczenie TCEC w przemyśle. Szczegółowo omówiono również stopień zaawansowania modelowania matematycznego i badań eksperymentalnych tych układów oraz wskazano na kierunki dalszych badań.
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