PREGLED HIBRIDNIH TERMOELEKTRIČNIH SISTEMOV

The primary objective of this paper is to review state-of-the-art hybrid photovoltaic/thermal systems and their performance analysis. The paper is designed to facilitate the comparison and evaluation of results obtained by other authors. The review was carried out for different types and designs of photovoltaic/thermal modules in indoor and outdoor conditions, as well as for different cooling types and materials.Cilj prispevka je pregled stanja hibridnih termoelektričnih sistemov in njihove učinkovitosti delovanja. Struktura prispevka je tematsko zasnovana tako, da olajša primerjavo in ovrednotenje rezultatov meddrugimi študijami. Pregled je izveden za različne tipe in oblike termoelektričnih modulov, ter za različne vrste hlajenja in uporabljenih materialov

STATIČNI MODEL TEMPERATURNE PORAZDELITVE V FOTONAPETOSTNEM MODULU

The primary objective of this paper is to present a static model for calculating the temperature distribution in a photovoltaic module using the finite element method. The paper presents in more detail the theoretical background of solar radiation, heat transfer, and the finite element method. The results of the static model are evaluated using temperature measurements of a photovoltaic model, which were performed at the Institute of Energy Technology, Faculty of Energy Technology, University of Maribor. The results of the regression analysis show a good concurrence between the measured and modelled values of the temperature of the photovoltaic module, especially on days with a higher share of the direct component of solar radiation.Glavni cilj tega prispevka je predstavitev statičnega modela za izračun temperaturne porazdelitve v fotonapetostnem modulu po metodi končnih elementov. V prispevku je podrobneje predstavljeno teoretično ozadje sončnega sevanja, prenosa toplote in metode končnih elementov. Rezultati statičnega modela so ovrednoteni z meritvami temperature fotonapetostnega modela, ki so bile izvedene na Inštitutu za energetiko (Fakulteta za energetiko Univerze v Mariboru). Rezultati regresijske analize med izmerjenimi in izračunanimi vrednostmi temperature fotonapetostnega modula prikazujejo dobro ujemanje predvsem v dnevih z večjim deležem neposredne komponente sončnega sevanja

MERILNA NAPRAVA ZA PREIZKUŠANJE TISKANIH VEZIJ IZ PROIZVODNJE

The paper presents an efficient way to evaluate and determine the quality of an assembled printed circuit board coming off the production line. A printed circuit board assembly consists of electronic devices soldered to the printed circuit board, which provides the electrical connections. After assembling the printed circuit board, a function test needs to be performed to guarantee the quality of the product. Usually, the assembly lines are equipped with cameras that detect inaccuracies such as missing components. This level of quality assurance is sometimes not enough, and we need to add another degree of precaution. In addition to camera inspections, electronic measurements must be conducted. The process needs to be automated to provide repeatability and speed. The paper evaluates such a device and presents its advantages, disadvantages, and complexity. The device includes an electrical part that performs the measurements, a mechanical part that consists of a housing and a mounting nest, and a program that supervises the process.Raziskovalno delo predstavi efektiven način ocenjevanja in določanja kakovosti tiskanih vezij iz proizvodnih linij. Sestavljeno tiskano vezje zagotavlja električno povezavo prispojenim elektronskim komponentam. Po sestavi tiskanega vezja je potrebno izvesti funkcionalen preizkus, ki zagotavlja kakovost izdelka. Proizvodnje linije so ponavadi opremljene z inšpekcijskimi kamerami, ki odkrivajo nepravilnosti, kot so manjkajoče komponente. Vendar takšen način zagotavljanja kakovosti v nekaterih primerih ni zadosten, zato je potrebna dodatna raven nadzora. Poleg inšpekcij s kamerami je potrebno izvesti tudi električne meritve. Proces teh meritev mora biti avtomatiziran za zagotovljanje njegove ponovljivosti in hitrejše izvedbe. Raziskovalno delo ovrednoti pomen takšne naprave, predstavi njene prednosti in slabosti ter kompleksnost. Naprava obsega elektronski del, ki izvaja meritve, mehanski del, ki obsega ohišje in vpenjalno mesto, ter program, ki nadzira proces

ANALIZA GORLJIVIH FRAKCIJ V MEŠANIH KOMUNALNIH ODPADKIH IN EMBALAŽI TER IZRAČUN ENERGIJSKE VREDNOSTI

The present article analyses combustible fractions in mixed municipal waste and packaging and the calculation of energy value. Methods of thermal treatment of waste and methods of preparation ofalternative fuels and classifications are presented and described. The article describes the method of analysis of caloric values with which we determined the energy values of individual fractions. For theresearch, we also used two thermal analyses, with which we considered individual fractions, thermogravimetric analysis, and differential dynamic calorimetry. The article presents the results of boththermal analyses, with which we observe the responses of individual types of plastics at different temperatures and the change in physical and chemical properties. The problem we have analysed in this article is mainly recyclable plastic that can no longer be reused due to various factors. The results of the structural analysis of household waste collection are also presented and described; on the basis of the analysis, the energy value of the container of mixed municipal waste and the reasonableness of waste reuse are recalculated.Članek obravnava analizo gorljivih frakcij v mešanih komunalnih odpadkih in embalaži ter preračun energijske vrednosti. Predstavljeni in opisani so načini termične obdelave odpadkov ter metode priprave alternativnih goriv in klasifikacija. V članku je opisana metoda analize kaloričnih vrednosti, s katero smo določali energijsko vrednost posameznih frakcij. Za namen raziskave smo uporabili tudi dve termični analizi, s katerimi smo obravnavali posamezne frakcije, termogravimetrično analizo in diferenčno dinamično kalorimetrijo. V članku so predstavljeni rezultati obeh termičnih analiz, s katerimi opazujemo odzive posameznih vrst plastike pri različnih temperaturah ter spremembo fizikalnih in kemijskih lastnosti. Problematiko, ki smo jo analizirali v tem članku, predstavlja predvsem plastika, ki se lahko reciklira, vendar je zaradi različnih dejavnikov ni mogoče več ponovno uporabiti. Predstavljeni in opisani so tudi rezultati strukturne analize zbiranja odpadkov v gospodinjstvih in na podlagi analize preračuna energijska vrednost zabojnika mešanih komunalnih odpadkov ter smiselnost ponovne uporabe odpadkov

METODE RECIKLIRANJA FOTOVOLTAIČNIH MODULOV IN PROJEKCIJE ZA PRIDOBIVANJE ELEMENTOV V SLOVENIJI

This paper aims to present different methods of recycling photovoltaic modules, which were researched by different institutes. Significant importance has been attributed to photovoltaic modules in the Renewable Energy sector, thereby contributing to the global transition towards sustainable energy sources. However, as the lifespan of these modules comes to an end, effective recycling methods will become crucial to minimize the environmental impact and resource depletion. This paper highlights recent advancements in photovoltaic module recycling technologies, focusing on predicting the potential mass of a specific element that could be recovered through recycling in Slovenia, considering the installed capacity of solar power plants, which is approximately 1105 MW. A projection of materials that can be obtained through the recycling process of photovoltaic modules was conducted based on current installed capacity, and it was discovered that up to 2150 tons of silicon and 1025 tons of copper could be obtained by the recycling process. The acquisition of various materials would have a significant role in the production of new photovoltaic modules, thereby enabling sustainable manufacturing and contributing substantially to the circular economy.V članku so predstavljene različne metode reciklaže fotovoltaičnih modulov. Fotovoltaični moduli so v sektorju obnovljive energije izjemno pomembni, saj prispevajo h globalnemu prehodu k trajnostnim energetskim virom. Čeprav imajo relativno dolgo življenjsko dobo, se tudi ta s časom izteče, zato je vse bolj nujno odkriti učinkovite metode recikliranja, saj so ključne za zmanjšanje okolijskih vplivov in izčrpanja virov. V tem članku so poudarjeni nedavni napredki v tehnologiji reciklaže fotovoltaičnih modulov, pri čemer je pomembna projekcija potencialne mase določenih materialov, ki jih je možno pridobiti v procesu reciklaže ob upoštevanju inštalirane moči fotovoltaičnih elektrarn, ki trenutno znaša okoli 1105 MW. Iz rezultatov projekcije materialov je bilo ugotovljeno, da bi lahko s postopkom pridobili do 2150 ton silicija in 1025 ton bakra. Pridobitev različnih materialov bi imela pomembno vlogo pri proizvodnji novih fotovoltaičnih modulov, saj bi omogočila trajnostno proizvodnjo in bistveno prispevala h krožnemu gospodarstvu

DOLOČITEV PROIZVEDENE IN PORABLJENE ELEKTRIČNE ENERGIJE STANOVANJSKEGA OBJEKTA Z UPORABO GRAFIČNEGA UPORABNIŠKEGA VMESNIKA

The primary objective of this paper is to present a graphical user interface for the calculation of electricity produced by a photovoltaic system and electricity consumed by a heat pump. The produced electricity is determined by a multi-year average of measurements of the global and diffuse power density of solar radiation for several places in Slovenia, while consumed electricity is determined based on the required heat for heating a residential building and domestic water. The calculation of produced and consumed electricity is validated by measurements on a real system. The developed graphical user interface enables simple user inputs of the photovoltaic system, heat pump, and the considered residential building, and provides a comprehensive tech-nical analysis for installing both systems at the same location.Glavni cilj tega prispevka je predstavitev grafičnega uporabniškega vmesnika za izračun proizvedene električne energije s fotonapetostnim sistemom in porabljene električne energije s toplotno črpalko. Predvidena proizvedena električna energija je določena z večletnimi povprečji meritev globalne in difuzne gostote moči sončnega sevanja za več krajev po Sloveniji, medtem ko je poraba električne energije določena na podlagi toplote za ogrevanje stavbe in sanitarne tople vode. Izračun proizvedene in porabljene električne energije je ovrednoten z meritvami na realnem sistemu. Izdelan grafični uporabniški vmesnik predvideva preproste uporabniške vnose fotonapetostnega sistema, toplotne č rpalke in obravnavanega objekta ter podaja celovito tehnično analizo za postavitev obeh sistemov hkrati

Evaluation of Different Methods for Voltage Sag Source Detection

This paper compares and evaluates three different methods for voltage sag source detection. First method (method I) is based on the assumption, that the energy flow at the monitoring point increases during downstream events and decreases during upstream events. Second and third method (methods II and III) are both based on the assumption that currents measured at the monitoring point increase during downstream events and decrease during upstream events. The slope of a current-voltage trajectory is investigated in method II, while a real current component is observed within method III. Both current-based methods (II and III) require fundamental harmonic components of sampled voltages and currents, which are extracted using discrete orthogonal series expansion, such as Fourier or Walsh. Algorithms of this type are especially appropriate for studying steady-state and periodically repeating conditions. Voltage sags are, on the contrary, transient disturbance events. Thus, usage of the discussed algorithms may not be appropriate. Furthermore, criteria within methods II and III are checked for each phase individually. In the cases of asymmetrical voltage sags exact interpretation of the obtained results, therefore, might not be possible. Method I is, on the contrary, based on instantaneous values of line voltages and currents, while three-phase criterion is used. An exact interpretation of the results obtained by this method is, therefore, also possible in cases of asymmetrical voltage sags. All the discussed methods for voltage sag source detection have been tested by applying extensive simulations and field tests. The results for ground faults, asymmetrical voltage sags, upstream events and motor starting have been analyzed in order to evaluate all the discussed methods. The obtained results show that all discussed methods are very successful in cases of heavy motor starting and other symmetrical voltage sags. In cases of asymmetrical voltage sags the methods II and III do not work well, especially for those originating from the upstream side, while the method I is not successful only in particular cases of voltage sags due to upstream ground faults. Based on the performed evaluation it can be concluded, that further development is still needed to increase the degree of confidence in the discussed methods

Pregled hibridnih termoelektričnih sistemov

The primary objective of this paper is to review state-of-the-art hybrid photovoltaic/thermal systems and their performance analysis. The paper is designed to facilitate the comparison and evaluation of results obtained by other authors. The review was carried out for different types and designs of photovoltaic/thermal modules in indoor and outdoor conditions, as well as for different cooling types and materials.Cilj prispevka je pregled stanja hibridnih termoelektričnih sistemov in njihove učinkovitosti delovanja. Struktura prispevka je tematsko zasnovana tako, da olajša primerjavo in ovrednotenje rezultatov med drugimi študijami. Pregled je izveden za različne tipe in oblike termoelektričnih modulov, ter za različne vrste hlajenja in uporabljenih materialov