Search

Flood frequency analysis was performed on annual maxima series for 90 years (1928–2017) of discharge data recorded at the Sremska Mitrovica gauging station on the Sava River. The three-parameter distributions (PearsonIII, Log-PearsonIII) are more suitable for modelling annual maxima than distribution functions with only two parameters (Normal, Log-normal, Gumbel). The Mann–Kendall test statistic indicated that there is no statistically significant trend identified in annual maximum discharges or average annual discharges. A positive increasing trend was observed in annual temperature, while annual precipitation shows a decreasing trend which is non-significant. The seasonality analysis found a statistically non-significant weak negative trend in discharge in spring, summer and autumn and a statistically non-significant weak positive trend in winter. During winter, spring, and summer a non-significant negative trend in precipitation was observed, while autumn has experienced a statistically significant increasing trend. Temperatures show a positive trend in all seasons, but only temperatures during the warm period show a statistically significant increase. The results demonstrate that decreasing discharges of the Sava River at the Sremska Mitrovica gauging station are mainly the consequence of decreasing precipitation and increasing temperature (increasing evaporation), which is consistent with the results of other studies of the region.

Na območju občine Kranjska Gora smo na izbranih hudournikih (Martuljek, Mlinca, Pišnica, Sava Dolinka in Triglavska Bistrica) z Dopplerjevim profilnim merilcem pretočnih hitrosti FlowTracker2 opravili meritve hitrosti in pretoka vode. Skupno smo na sedmih merilnih mestih v letih 2020 in 2021 opravili 482 meritev hitrosti vode. Na vsakem merilnem mestu smo pretočni profil razdelili na več vertikal (širina vertikale med 1/2 in 1/20 širine pretočnega profila) in v posameznih vertikalah opravili meritve hitrosti vode na 60 % njene globine. Povprečna izmerjena hitrost vode v posamezni vertikali je znašala 0,717 m/s, najvišja pa 1,881 m/s, najnižja pretočna hitrost vode je znašala 0,300 m/s, najvišja pa 1,153 m/s. Pretok vode smo izračunali po metodi hitrost-površina, vrednosti se gibljejo od 0,113 m3/s do 2,591 m3/s. Relativna napaka meritev pretočne hitrosti vode glede na število vertikal znaša med 0,2 % in 75,1 %, relativna napaka meritve pretoka vode pa med 0,6 % in 58,8 %. Relativna napaka meritev pada z naraščanjem števila vertikal. Potrebno število vertikal za relativno napako meritve pod 5 % je v primeru meritev pretočne hitrosti vode 7,1, v primeru pretoka vode pa 7,8. Maksimalna širina vertikale za relativno napako meritve pod 5 % je v primeru meritev pretočne hitrosti vode 62 cm, v primeru pretoka vode pa 55 cm. In the Municipality of Kranjska Gora, measurements of the speed and flow of water on selected torrents (Martuljek, Mlinca, Pišnica, Sava Dolinka, and Triglavska Bistrica) were performed with the help of the FlowTracker2, the Acoustic Doppler Velocimeter. In 2020 and 2021, 482 water speed measurements at 7 measuring points were carried out in total. At each measuring point, the cross-section of the watercourse was divided into several sections (section width between 1/2 and 1/20 cross-section width) with measurements of water velocity in verticals between sections performed at 60% of water depth. The average measured water velocity in each vertical was 0.717 m/s while the highest was 1.881 m/s. Moreover, the lowest water flow was 0.300 m/s and the highest amounted to 1.153 m/s. The water flow was calculated using the speed-surface method, with values ranging from 0.113 m³/s to 2.591 m³/s. The relative error of the water flow rate relative to the number of verticals is between 0.2% and 75.1%, while the relative error of the water flow measurement ranges between 0.6% and 58.8%. The relative error of the measurements decreases with the increase in the number of sections or verticals. The required number of sections to make the relative measurement error below 5% in the case of water flow rate measurements is 7.1 while it amounts to 7.8 in the case of water flow.

Hlajenje sistemov v električnih vozilih je nepogrešljivo, saj to zagotavlja maksimalno zmogljivost delovanja sistemov pri njihovem obratovanju. Izmed poznanih načinov hlajenja, kot so zračno hlajenje, hlajenje z ventilatorjem, hlajenje z materialom s fazno spremembo in hlajenje s hladilnim sredstvom, najboljše in najbolj konstantno vzdrževanje temperature sistema omogoča posredno hlajenje s hladilnim sredstvom. Hladilno sredstvo, katerega predstavlja zmes vode in glikola, kroži po ceveh in pri tem odvaja toploto iz področij z višjo temperaturo. Za kroženje hladilnega sredstva skrbi hidrodinamična električno-gnana centrifugalna oziroma turbinska črpalka. Cilj zaključnega dela je zasnova testnega mesta za merjenje karakteristik črpalk za namen hlajenja in gretja sistemov v električnih vozilih s poudarkom, da bo sistem povzročal čim manjšo izgubo tlaka ter omogočal natančne meritve. Kandidat naj na preizkuševališču določi karakteristiko turbinskih črpalk, uporabljenih za ta namen in jih primerja s črpalkami, ki uporabljajo tehnologijo COR. Rezultate naj analizira in predlaga nadaljnje delo. Cooling systems in electric vehicles is indispensable to ensure maximum performance of the systems when they are in operation. Of the known cooling methods such as air cooling, fan cooling, phase change material cooling and refrigerant cooling, indirect refrigerant cooling provides the best and most constant system temperature maintenance. The refrigerant, which is a mixture of water and glycol, circulates through the pipes, removing heat from areas having a higher temperature. The circulation of the refrigerant is handled by a hydrodynamic electrically driven centrifugal pump. The purpose of this thesis is to design a test bench to measure the characteristics of pumps for cooling and heating systems in electric vehicles, with the emphasis on minimising the pressure loss of the system and allowing accurate measurements. The candidate shall characterise the turbine pumps used for this purpose at the test site and compare them with pumps using COR technology. The results should be analysed and further work suggested.

Diplomsko delo je nastalo ob načrtovanju vodne skulpture na Slovenski cesti v Ljubljani. Potrebno je bilo analizirati delovanje namenskih šob, ki oblikujejo vodne curke kot del vizualne podobe objekta. Ker so bile mere fontane določene vnaprej, je bil namen tudi preveriti obratovanje sistema znotraj predvidenih dimenzij. Opazovali smo obliko vodnih curkov in njihovo medsebojno interakcijo ter določili mesto razpada curkov na manjše kapljice. To namreč negativno vpliva na vizualno podobo objekta, obenem pa kolizija curkov predstavlja potencialni vir izgub vode zaradi pršenja. This thesis was written in process of designing a water fountain on Slovenska cesta street in Ljubljana. It was necessary to analyze the characteristics of water nozzles which will be used in the system. These nozzles form water jets as a part of visual effect. Some dimensions were determined in advance, so it was also necessary to verify that the system will operate within its determined boundaries. We observed the shape of water jets and their mutual interaction. We also attempted to locate the position at which these jets fall apart. Such events may harm the visual effect of the fountain. In addition, the collision of water jets could also lead to spraying effect and water loss, which is not desired. The fountain will be operating within a closed system, with water jets falling into a preinstalled reservoir, which supplies the pumps.

Hidroelektrarne omogočajo energetsko učinkovito, okolju prijazno, fleksibilno in zanesljivo pridobivanje električne energije. Izkoriščanje energije vodotokov ter sočasno zagotavljanje protipoplavne zaščite in zanesljivosti oskrbe s pitno vodo sta njihovi strateško pomembni prednosti. Poleg tega se z omilitvenimi ukrepi, implementacijami okoljsko najsprejemljivejših rešitev in rednim izvajanjem monitoringov doseže minimalne vplive na okolje, s čimer je hidroenergija najbolj čista oblika energije. Primat med obnovljivimi viri jim zagotavljajo predvsem stanovitnost, nizki obratovalno investicijski stroški na enoto proizvedene energije in možnost sodelovanja pri regulaciji sistemskih parametrov. Izmed vseh obnovljivih virov predstavljajo največjo rotacijsko maso, ki je ključna za zagotavljanje stabilnosti elektroenergetskega sistema in dušenje dinamičnih prehodnih pojavov. Namen magistrskega dela je izdelati matematične modele hidroelektrarn na spodnjem toku reke Save, z upoštevanjem dejanskih obratovalnih parametrov hidroelektrarn. Modeli omogočajo primerjavo izračunanih in v sklopu prevzemno-garancijskih meritev izmerjenih vrednosti pretokov, moči, neto padcev in izkoristkov. V nadaljevanju je potrebno modele uporabiti še za določitve optimalne angažiranosti posameznih agregatov obravnavanih hidroelektrarn. To nam omogoča ovrednotenje dejanskega vklopno-izklopnega algoritma agregatov s stališča minimizacije pretoka in s tem izboljšanja izkoristka potencialne energije, nakopičene znotraj pretočne akumulacije. Prvi del magistrskega dela obsega predstavitev hidrološkega potenciala, hidroelektrarn, njihovo delitev in sestavne dele. Opisane so tudi energijske pretvorbe, preko katerih iz energije vodotoka pridobivamo električno energijo. Sočasno s tem nastopajo tudi izgube, ki definirajo izkoristek hidroelektrarne v posamezni obratovalni točki. Opisane so v poglavju 6, kjer je natančno predstavljen tudi njihov izračun. Prikazani so tudi parametri, preko katerih lahko pridemo do zaključkov, kako prisotne izgube v največji meri znižati. V drugi polovici magistrskega dela je predstavljeno modeliranje hidroelektrarn na spodnjem toku reke Save, torej HE Boštanj, HE Arto-Blanca, HE Krško in HE Brežice, izvedeno v sklopu magistrskega dela. V Pythonu izdelani matematični modeli temeljijo na školjčnih diagramih, podanih s strani proizvajalca turbin oziroma izmerjenih v sklopu prevzemno-garancijskih meritev. Z odčitkom poljubnega, dovolj obsežnega nabora točk školjčnega diagrama in z dvodimenzionalno interpolacijo, celotno obratovalno področje turbine zapišemo v numerični obliki. Zaradi omejitev turbine moramo školjčni diagram omejiti, kar dosežemo z zapisom ustreznih funkcij. V nadaljevanju je model grajen na podlagi fizikalnih osnov in funkcij izgub iz garancijskih meritev, tako, da iz podatkov o obratovalni moči in kotah zgornje ter spodnje vode določimo potreben pretok, moč turbine, neto padce ter izkoristke posameznih elementov in celotne hidroelektrarne. Natančnost matematičnih modelov pri določanju parametrov obratovanja je dokazana s primerjavami izračunanih in izmerjenih vrednosti. V sklepnem delu magistrskega dela so predstavljeni rezultati optimizacije obratovanja hidroelektrarn, ki je izvedena s predstavljenimi modeli. Modeli omogočajo določitev optimalne razporeditve obremenitve med posamezne agregate, z namenom minimizacije pretoka in s tem prihranka energije, ki jo akumuliramo v pretočnih akumulacijah. Na podlagi obratovalne moči in bruto padca namreč program določi vse možnosti razporeditve obremenitve in z izračuni poišče kombinacijo, ki zahteva najnižji pretok oziroma omogoča najvišji izkoristek. Pri tem so upoštevane vtočne in iztočne izgube, obratovalna točka turbine in izkoristek generatorja. Na podlagi analize omejenega časovnega obdobja obratovanja hidroelektrarn je opredeljen tudi prihranek energije, dosežen z optimalno razporeditvijo obremenitve. Zaradi histereze pri dejanskem obratovanju sicer pride do nekoliko višjih pretokov, vendar je slednje neobhodno za znižanje obremenitev opreme in s tem podaljšanje njihove življenjske dobe. Hydropower plants are an energy efficient, environmentally friendly, flexible, and reliable facilities for conversation of energy of water into electric energy. Using the energy of water, while at the same time providing flood protection and security of drinking water supply are strategically important benefits of hydropower plants. In addition, through mitigation measures, implementation of the most environmentally acceptable solutions and regular monitoring, the minimal environmental impacts are achieved, making hydropower the cleanest form of energy. Stability, low operating and investment costs per unit of produced energy and a possibility to participate at control of power system parameters, provide them a leading position between renewable sources of energy. They represent the largest rotating mass of all renewable sources, which is the key to ensure stability of the power system and resilience to dynamic transients. The aim of master thesis is to make mathematical models of hydropower plants on the lower parts of the Sava River, considering actual operational parameters of the hydropower plant. The models allow comparison of the calculated and measured values of flows, powers, net heights of water and efficiencies. The models can be used to determine the optimal engagement of individual units or the distribution of the total power of the hydropower plant between individual production units. This allows us to evaluate the actual on/off algorithms of aggregates from the point of view of minimizing the flow and thus improving the efficiency of potential energy within the flow accumulations. The first part of the master thesis includes an introduction to hydropotential, hydropower plants, their types, and components. It also describes the energy conversions that generate electric energy from the energy of a water. At the same time, there are losses that define the efficiency of the hydropower plant at each operating point. They are described in Chapter 6, where their calculation is also presented in detail, together with the parameters that can be used to draw conclusions on how to minimise the losses. The second part of the master thesis presents the modelling of hydroelectric power plants on the lower part of the Sava River, i.e., HPP Boštanj, HPP Arto-Blanca, HPP Krško and HPP Brežice, performed as part of a master thesis. Mathematical models of hydropower plants are made in Python and based on shell diagrams provided by the turbine manufacturer or measured as part of the acceptance and guarantee measurements. By reading any sufficiently large set of points on the shell diagram and the two-dimensional interpolation, the entire operating range of the turbine is written in a numerical form. Due to the constraints of the turbine, we need to constrain the shell diagram, which is achieved by writing the appropriate functions. Models are built based on the physical fundamentals and loss functions from the guarantee measurements, by determining the required flow, turbine power, net heights, and efficiencies of the individual elements and of the whole hydropower plant from the operating power and the level of the upper and lower water. The accuracy of the model calculations is demonstrated by comparisons of calculated and measured values to demonstrate the accuracy of the calculations and adequacy of the models. In the final part of the master thesis, the results of the optimisation of hydropower plants operation using the developed models are presented. The models allow to determine the optimal load distribution between the individual aggregates to minimise the flow and thus save the energy stored in the flow storage. Based on the operating power and the gross height difference, the software determines all the load distribution options and uses calculations to find the combination that requires the lowest flow rate and thus achieves the highest efficiency. This considers the inlet and outlet losses, the turbine operating point and the generator efficiency. The calculations have been used to verify and validate the actual on/off algorithms of the generators, which also provide an on/off hysteresis. Based on the actual and adjustable timetable, the energy saving of the optimal operation compared to the actual one is finally determined. Hysteresis may result in higher flows, but it is essential to reduce the stresses on the equipment and thus prolong their lifetime.

Podnebna spremenljivost pomembno vpliva in spreminja potek dogajanja v hidrološkem krogu. Vse dosedanje analize kažejo na to, kako pomembna so prizadevanja za prilagajanje novim podnebnim spremembam, kako lahko zgodnje zaznavanje hidroloških ekstremov in njihovo dobro poznavanje pripomore k boljši pripravljenosti strokovnih služb in s tem učinkovitejšim ukrepom. Diplomsko delo obsega statistično analizo specifičnih značilnih pretokov slovenskih rek, in sicer srednjih malih, srednjih pretokov ter visokovodnih konic, za 58-letno obdobje (1960–2018). Analiza je narejena za 50 vodomernih postaj, zajetih v uradno mrežo vodomernih postaj, katere podatke o pretokih lahko prosto pridobimo na spletni strani Agencije Republike Slovenije za okolje (ARSO). Glede na prikaz specifičnih značilnih vrednosti pretokov smo ugotovili, da imajo visokovodne konice na večini obravnavanih vodomernih postaj večji razpon vrednosti kot srednji mali in srednji pretoki. Najbolj izrazito se to odraža pri srednjih pretokih, medtem ko so za visokovodne konice kot bolj mokri bolj izraziti jesenski meseci. Prostorsko gledano smo ugotovili, da so specifične vrednosti srednjih malih in srednjih pretokov razporejene po Sloveniji precej enakomerno, do razlik prihaja samo pri visokovodnih konicah. Pri srednjih malih in srednjih pretokih smo s pomočjo hierarhičnega razvrščanja vodomerne postaje razdelili v 5 skupin, pri visokovodnih konicah pa so se oblikovale 4 skupine. Za večino vodomernih postaj smo ugotovili, da sledijo dolgoletnemu povprečju, da so v poletnih mesecih zabeležene najnižje vrednosti podatkov, v nekaterih pomladnih in jesenskih mesecih pa so te vrednosti višje. Climate variability has a significant impact on hydrological cycle and changes it. All of the analyses so far show the importance of efforts to adapt to new climate changes, how early detection and a good understanding of hydrological extremes can help to improve the preparedness of professional services and thus contribute to more effective actions. The thesis includes a statistical analysis of specific characteristic discharges of Slovenian rivers, namely mean small, mean discharges and the highest discharges for a 58-year period (1960-2018). The analysis was performed for 50 water gauging stations belonging to the official network of water gauging stations, whose hydrometric flow data are freely available on the website of the Slovenian Environment Agency (ARSO). When presenting the specific characteristic values of the discharges, we concluded that the highest discharges at most of the studied gauging stations have a larger range of values than the mean small and mean discharges. This is most evident for the mean discharges, while for the highest discharges the autumn months are more prominent as the wetter months. From the spatial perspective we can conclude that the indication for the specific values of the mean small and mean discharges is quite evenly distributed across Slovenia, with differences only for the highest discharges. In case of mean small and mean discharges we divided the gauging stations into 5 groups using hierarchical clustering, while for the highest discharges 4 groups were formed. Most gauging stations followed the long-term average, with the summer months recording the lowest data values and some spring and autumn months recording higher values.

Tento článek se zabývá vstřikováním do plastové formy. Jedná se o netradiční přístup ke vstřikování zejména proto, že k výrobě formy je použit 3D tisk. Pro srovnání byla forma stejného tvaru vyrobena z běžného materiálu (hliníku). Vlastnosti plastové formy pak byly porovnány s hliníkovou formou. Jako hlavní nedostatek se ukázala tvorba přetoků. Úprava formy byla navržena ve dvou variantách, z nichž jedna byla realizována. Výhoda řešení zabránění tvorby přetokům byla popsána. Nakonec byly na základě provedených zkoušek shrnuty další možnosti řešení This article deals with the injection moulding into the plastic mould. This is an unconventional approach to injection moulding, especially because the 3D printing is used to produce the mould. The mould with the same shape was made of a conventional material (aluminium) for comparison. The properties of the plastic mould were then compared to the aluminium mould. The flash was seen as the main shortcoming. The modifications of the mould were suggested in two variants, one of them was implemented. The advantage of the flash solution was described. Finally, other solution options were summarized based on the performed testing.

Predmet diplomske naloge je izračun energetskega potenciala vodotoka Davče in primerjava dobljenih rezultatov s predhodnimi študijami. V prvem delu so podane definicije in opisane metodologije izračuna različnih tipov energetskih potencialov, s katerimi lahko opišemo energetske karakteristike posameznega vodotoka. V drugem delu naloge smo določili energetske karakteristike na primeru vodotoka Davča, pritoka Selške Sore. Ker hidroloških podatkov, konkretno za vodotok Davča, ni na voljo, smo jih določili na podlagi pretokov Selške Sore s predpostavko, da gre za hidrološko primerljivi porečji. Vse potrebne podatke za preračun energetskega potenciala smo pridobili iz javnih podatkovnih baz. Preračun smo izvedli za vse karakteristične tipe energetskih potencialov (bruto, tehnični in ekološki energetski potencial) za vodotok Davča z upoštevanjem hidrološkega niza 1991-2019. Rezultate naše analize smo primerjali z rezultati energetske študije iz leta 1997 in ugotovili zadovoljivo ujemanje rezultatov, kar potrjuje predlagano metodologijo za izračun energetskega potenciala na manjših vodotokih, kar je dejansko bil namen naše naloge in dosežen cilj: vzpostavitev metodologije za posplošeno določevanje celotnega hidroenergetskega potenciala kateregakoli vodotoka. Na ta način se lahko v bodoče izdelujejo primerljive, zanesljive in standardizirane analize možne energetske izrabe med različnimi vodotoki. The subject of the diploma thesis is the calculation of the energetic potential of the Davča watercourse and the comparison of the obtained results with previous studies. In the first part, definitions and methodologies for calculating different types of energetic potentials are given, with which we can describe the energetic characteristics of an individual watercourse. In the second part of the thesis, we determined the energetic characteristics on the example of the Davča watercourse, a tributary of the Selška Sora River. As hydrological data, specifically for the Davča watercourse, are not available, they were determined on the basis of the flows of the Selška Sora River with the assumption that they are hydrologically comparable river basins. All necessary data for the calculation of energetic potential were obtained from public databases. The calculation was performed for all characteristic types of energetic potentials (gross, technical and ecological energetic potential) for the Davča watercourse, taking into account the hydrological series 1991-2019. We compared the results of our analysis with the results of the 1997 energy study and found a satisfactory match, which confirms the proposed methodology for calculating energetic potential in smaller watercourses, which was actually the purpose of our thesis and achieved goal: establishing a methodology for generalized determination of energetic potential of watercourse. In this way, comparable, reliable and standardized analyses of possible energy use between different watercourses can be made in the future.

V zaključni nalogi obravnavamo stabilnostni odziv zaprtega sistema več povezanih sferičnih membran. Specifično nas zanima relacija med tlakom in pretokom, ki se pojavi med posameznimi membranami, ter odziv zaprtega sistema, če spremenimo vhodne parametre, vezava pa ostane nespremenjena. V našem primeru smo se osredotočili na sisteme z dvema, tremi in štirimi povezanimi sferičnimi membranami ter za vse napisali računalniški program, ki iteracijsko računa dogajanje v sistemu membran, dokler te ne preidejo v ravnovesno stanje. Ugotovili smo, da ob isti vezavi sferičnih membran in variaciji njihovega zaporedja dobimo drugačen odziv sistema. Ob tem smo tudi ugotovili, da pri vezavi treh ali več sferičnih membran te v ravnovesnem stanju ne ostanejo na delu grafa z negativnim naklonom. In the last thesis we discuss the stability response of a closed system of several interconnected spherical membranes. In particular, we are interested in the relationship between pressure and flow that occurs between the individual membranes and in the response of a closed system when we change the input parameters and the connection remains unchanged. In our case, we focused on systems with two, three, and four interconnected spherical membranes and wrote a computer program for all of them that iteratively calculates what happens in the membrane system until they reach equilibrium. We found that the system responds differently when we connect the spherical membranes in the same way and vary their order. We also found that when three or more spherical membranes are connected, they do not remain in the equilibrium state at the part of the graph with a negative slope.

Diplomska naloga se ukvarja z razvojem avtomatskega sistema za čiščenje filtrov, ki se nahaja na prezračevalnem sistemu pred izmenjevalcem toplote. Izbrani so bili primerni prezračevalni filtri z zadostno kvaliteto filtracije. Zasnovan je sistem spiranja umazanije s filtrov s silo vodnega curka. Izračunana je pralna sila vodnih curkov, na podlagi katere je izbran primeren pretok in vrsta šobe. Izračunan in numerično simuliran je bil tudi padec tlaka v fleksibilni cevi, ki dovaja vodo do kolektorja na katerem so šobe. Zasnovan je bil tudi horizontalni in vertikalni pomik sistema in ohišje sistema, ki ga pritrdimo na izmenjevalec toplote. The thesis consists of the development of an automatic filter cleaning system attached to the ventilation system in front of the heat exchanger. Suitable filters with sufficient filtration quality were selected. A system for washing the dirt out of the filters with water jet was designed. The washing power of the water jets is calculated after which the appropriate water flow rate and nozzle type are selected. The pressure drop in the flexible pipe supplying water to the collector on which the nozzles are, was also calculated and numerically simulated. The horizontal and vertical displacement of the system and the housing of the system, attached to the heat exchanger were designed as well.

Pri razvoju malih črpalk za pomoč levemu ventriklu pešajočega srca se v zadnjih dvajsetih letih vedno bolj uporablja računalniška dinamika tekočin, ki je ob primerni validaciji zelo uporabno orodje pri snovanju naprav. Pri doktorski disertaciji smo se osredotočili na simulacije enofaznega toka Newtonske tekočine pri konstantni temperaturi ob uporabi naprednih turbulentnih modelov družin DES in SAS, jih primerjali s široko uporabljenim SST-k? modelom in jih na koncu validirali z eksperimentom. Naloga je sestavljena iz treh delov (raziskav). Pri I. raziskavi smo izvedli preliminarni splošni preizkus na enostavni geometriji iztočne šobe, ki je bila del iniciative za razvoj numeričnih simulacij s strani Uprave ZDA za hrano in zdravila (ang. Federal Drug Administration- FDA). Pri II. raziskavi smo primerjali tokovne karakteristike ?p(Q) male komercialne črpalke HeartAssist5 z vodo in jih validirali. Pri III. raziskavi pa je bila napravljena raziskava na transparentnem preizkuševališču, izdelanem po geometriji komercialne črpalke aVAD, kjer smo numerične simulacije primerjali z merilno metodo PIV. Ugotovili smo, da se pri nominalnih delovnih pogojih naprav najbolje ujemata z eksperimentalnimi podatki napredna turbulentna modela SBES (I. in III. raziskava) in SAS (II. raziskava). SBES turbulentni model je zadnja nadgradnja modela-DES. Kriteriji, po katerih so modeli primerjani, so primerljivi računski časi izračunov na enakih numeričnih mrežah, enakem številu računskih jeder superračunalnika ter ujemanju eksperimentalnih parametrov izračunanih hitrosti in tlaka v primerjavi z numerični simulacijami. During the development process of the left ventricular assist devices (LVAD) the computational fluid dynamics (CFD) is increasingly used which is a valuable tool if validated with the experiment. In this thesis we have focused on CFD simulations of one phase, newtonian flow with a constant temperature using advanced turbulence models from DES family and SAS formulation. The comparison has been performed with widely used SST-kω model and all cases have been validated experimentally. Our task was divided into three parts (research cases). In the first case we have investigated the nozzle benchmark which was a part of a Food and Drug Administration (FDA) backed research iniciative with the goal to promote the CFD in mechanics in medicine. In the second case the Δp(Q) flow characteristics were compared in small commercial HeartAssist 5 LVAD using water as fluid. In the third case the investigation was performed on a transparent housing built on a comercial aVAD small pump, where the numerical simulations were compared with the results of Particle Image Velociometry (PIV) method. It has been concluded that the best results were obtained by SBES (I. and III. research case) and SAS turbulence models (II. research case). SBES turbulence model is the latest most updated derivative of the DES model. The criteria for the comparison was chosen like velocity, pressure difference and simulation time on the same hardware setup.

Ko govorimo o kakovosti zraka ločimo med kakovostjo zraka na prostem in v notranjosti. Kakovost zraka na prostem je odvisna od vsebnosti onesnažil v zunanjem zraku in jo izražamo z indeksom kakovosti zraka, kakovost zraka v notranjosti pa se nanaša na kakovost zraka v prostoru in stavbah okoli le-tega. Kakovost zraka je tesno povezana s prezračevanjem ter ima velik vpliv na zdravje posameznika. Kakovost zraka v prostoru nadzorujemo preko nadzora virov, prezračevanjem ter morebitnim čiščenjem zraka in je podana kot subjektivna ocena posameznika na podlagi zaznavanja zraka v prostoru. Da bi zagotovili zdrav zrak ustrezne kakovosti v prostoru, je potrebno, da sledimo smernicam, ki so določene s strani pristojnih organov. When we talk about air quality, we distinguish between outdoor and indoor air quality. Outdoor air quality depends on the content of pollution in the outdoor air and is expressed by the index of air quality, indoor air quality and refers to the quality of indoor air in the buildings around it. Air quality is closely related to ventilation as it has a major impact on an individual’s health. The quality of the air in the room is controlled through the control of sources, ventilation and possible air purification and is given as a subjective assessment of the individual based on the perception of air in the room. In order to ensure healthy air of adequate quality in the room, it is necessary to follow the guidelines set by the competent authorities.

V sklopu zaključne naloge smo opravili eksperimentalne meritve za potrebe razvoja merilnega testnega dela, kjer bo formiran superkavitacijski oblak. Različne geometrije smo zasnovali v modelirniku (SolidWorks), jih dali izdelati iz akrilnega stekla in zasnovali eksperimentalno progo, na kateri smo izvajali meritve, rezultate pa smo nato analizirali. Merilna proga je omogočala hitro in enostavno menjavo različnih geometrij testnih delov. Kavitacijski oblak formiran znotraj testnega dela je bil okarakteriziran s pomočjo tlačnih razmer pred in za testnim delom, meritvami pretoka tekočine skozi testni del in vizualizacijo s pomočjo hitre kamere. Cilj naloge je bil okarakterizirati različne geometrije Venturijevih zožitev za formacijo superkavitacijskega oblaka. Želeli smo razviti superkavitacijski oblak, ki bi zavzemal čim večji volumen pretočnega kanala znotraj zožitve. As part of the final task, we performed experimental measurements for the needs of the development of the measurement test part, where a supercavitation cloud will be formed. Different geometries were designed in the model (SolidWorks) from acrylic glass. We designed an experimental track on which we performed measurements, then analyzed the results. The measuring track made it possible to quickly and easily change the different geometries of the test parts. The cavitation cloud formed in the test section was characterized by pressure conditions before and after the test section, measurements of fluid flow through the test section, and visualization using a high-speed camera. The purpose of the task was to describe the different geometries of the Venturi constrictions for the formation of a supercavitation cloud. We wanted to develop a supercavitation cloud that would occupy as much of the flow channel volume as possible within the constriction.

Diplomsko delo obsega pregled trga in testiranje obstoječega prototipa ter dveh konkurenčnih pršilk. Pršilke smo med seboj primerjali na podlagi izmerjenega tlaka, pretoka in časa delovanja. Izvedeni so bili preračuni pretoka skozi šobe pri različnih tlakih in premerih šob, sile curka za različne površine šob in tlake, širine curka pršenja za različne šobe in oddaljenosti šobe od površine ter izgube tlaka v cevi za različne dolžine cevi. Na prototipu pršilke smo izvedli meritve pretokov in tlakov za različne šobe, izmerili čas delovanja pršilke z različnimi baterijami in izmerili smo širino curka pršenja. Izmerjene in izračunane rezultate smo med seboj primerjali in ovrednotili. Ugotovili smo, da večja kot je kapaciteta baterije, daljši je čas delovanja. Z večanjem pretoka, se povečuje tlak. Pretok je večji pri večjih izstopnih presekih šobe pri istih tlakih. Prav tako se povečuje sila curka z večanjem izstopne površine šobe pri istih tlakih. Širina curka je odvisna od kota pršenja šobe, tlaka in oddaljenosti šobe od površine. Z izbiro šobe določimo namen uporabe pršilke. The diploma thesis consists of a market overview and the testing of an existing prototype and two competing sprayers. The comparison between our prototype and other cordless pressure cleaners was based on measured pressure, flow and operating time. We performed measurements of flow rate through the nozzles at different pressures and nozzle diameters, jet forces for different nozzle surfaces and pressures, spray jet widths for different nozzles and nozzle distances from the surface, and pressure losses in the pipe at different pipe lengths. In addition, we measured flows and pressures for different nozzles, operating time and spray jet width on the prototype. We evaluated the measurement results and compared them with calculations. We found that the higher battery capacity means longer operating time. Increasing the flow rate results in an increase in pressure. The flow rate is higher at larger nozzle outlet cross sections at the same pressures. Also the blasting power increases with increasing nozzle outlet area at the same pressures. The jet width depends on the nozzle spraying angle, the pressure and the distance between nozzle orifice and target area. By selecting the nozzle we determine the intended use of the sprayer.

Diplomsko delo zajema področje iskanja maksimalnega toka v mrežah tokov. Osrednji namen je implementacija grafične aplikacije, ki omogoča prikazovanje vmesnih korakov pri izvajanju Ford-Fulkersonove metode in algoritma potisni-povišaj. Aplikacijo smo implementirali v programskem jeziku C# z uporabo ogrodja Windows Forms in knjižnice Microsoft Automatic Graph Layout. Aplikacijo in oba algoritma za iskanje maksimalnega toka smo uspešno implementirali. Opravili smo primerjavo algoritmov in ugotovili, da algoritem potisni-povišaj, pri uporabljenih grafih, v povprečju izvede več vmesnih korakov kot Ford-Fulkersonova metoda. Posledično se dlje časa izvaja in ima tudi višjo povprečno porabo pomnilnika. The graduation thesis covers the field of algorithms for finding the maximum flow in flow networks. The main purpose of the thesis is to implement a graphical application that allows visualization of intermediate steps during the execution of the Ford-Fulkerson method and the push-relabel algorithm. The application was written in the C# programming language with the use of the Windows Forms framework and the Microsoft Automatic Graph Layout library. The application and both algorithms have been successfully implemented. We performed a comparison between the implemented algorithms and found out that, in our graphs, the push-relabel algorithm has a higher average count of intermediate steps in comparison to the Ford-Fulkerson method. Consequently, it also has a longer execution time and higher memory usage.

Diplomsko delo obravnava razvoj merilnika pretoka in tlaka tekočin. Sistem merjenja je enostaven za uporabo. Uporabljamo znano metodo merjenja pretoka skozi venturijevo cev, ki je širše uporabljena tudi za različne aplikacije merjenja hitrosti, masnega in volumenskega pretoka fluidov. Z merjenjem razlike tlakov med ožjim in širšim premerom cevi in s pomočjo bernoullijevega zakona programsko izračunamo pretok fluida skozi cev. Ukvarjamo se z osnovnimi gradniki senzorja, na podlagi katerih se bodo v bodočih delih razvijale metode vrednotenja merjenih fizikalnih vrednosti. Fizikalne podatke merilnika prikazujemo na alfanumerični prikazovalnik merilnika in računalniški monitor. Zbrane informacije v določenem časovnem odseku zajamemo in jih prikažemo v grafih. The diploma thesis deals with the development of the flow by the pressure measurement of a fluid. The measurement system is easy to use, because it uses a well-known Venturi tube flow measurement method, which has been used in the past for various applications of speed measurement, mass and volume flow of fluids. It measures the difference in pressure between the narrower and wider diameter of the tube. With the use of programmed Bernoulli equation it calculates the flow of fluid. Data is displayed on the external display and computer monitor. All informations are collected and displayed on graphs.

V diplomskem delu so predstavljene meritve mikročrpalk. Uporabljajo se za meritve pretoka različnih tekočin in jih najdemo predvsem na mestih, kjer rabimo točne meritve majhnih pretokov (npr. v laboratorijskih meritvah). Prednost teh naprav je manjša velikost, nizka poraba energije, nizka cena, hitrost analize itd. Obstaja veliko vrst mikročrpalk v sami diplomi pa smo merili 2 in 3 nivojske mikročrpalke, izdelane v LMSE. Razlika je v tem, da 3 nivojske imajo različni reži(vhodna je večja od izhodne), 2 nivojske pa imajo enake. Cilj same diplomske naloge je bil, da najprej izmerimo osnovne podatke pri napetosti 100 V. Potem sledi meritev pretoka in tlaka pri spreminjanju frekvence. S tem smo videli kako se spreminja posamezna struktura in razlike pri tem. V laboratoriju niso imeli podatkov pri določenih črpalkah za amplitudah krmilne napetosti 120 V, zato smo v tem diplomskem delu izmerili lastnosti mikročrpalk v tem primeru. Za na konec pa smo morali izmeriti, kako se strmina karakteristike spreminja z upornostjo uporov. Istočasno pa smo opazovali obnašanje mikročrpalke, ko v kanal zaide mehurček zraka. Na koncu smo ugotovili, da so črpalne lastnosti odvisne od strukture mikročrpalke. Pri merjenju zraka smo opazili, da imajo 2 nivojske mikročrpalke višji pretok kot 3 nivojske. Grafični potek je v obeh primerih enakomerno naraščajoč. Meritve z vodo so pokazale, da pretok doseže 90% svoje vrednosti do 100 Hz. Graf pretoka strmo narašča do te frekvence potem pa se ustali oz. narašča zelo počasi. Večji pretok dosežemo s uporabo 2 nivojskih mikročrpalk. V primeru višje amplitudne napetosti so vrednosti bile višje. The diploma thesis presents micro pump measurements. These are used for the flow of various liquids and are found in places where accurate and low flow rates are required. This is for example in laboratories. The advantage of this is the smaller size, low power consumption, low cost, speed of analysis, etc. There are many types of pumps in the diploma itself, but we measured 2 and 3 level micro-pumps. The difference is that 3 levels have different slots and 2 levels have the same slots. The aim of the diploma paper was first to measure the basic data at a voltage of 100 V. Then to measure the flow and pressure when changing the frequency. With this, we have seen how each structure changes and the differences in it. In the laboratory itself, they did not have data on specific pumps for a 120 V amplitude voltage, so we checked what was going on with the device in this case. In the end, however, we had to measure how the slope of the characteristic changes with the resistance of the resistors. At the same time, we observed what happens if a bubble of air enters the channel. In the end, we found that depending on the structure itself, what characteristics each pump has. When measuring the air, we noticed that 2 level micropumps have a higher flow rate than 3 level pumps. In both cases, the graphical progress is steadily increasing. Measurements with water showed that the flow reaches 90% of its value up to 100 Hz. The chart itself rises steeply to this frequency and then slightly stabilizes or rises slightly. Higher flow rates are achieved by using 2 level micro-pumps. In the case of higher amplitude voltage, the values were higher.

Hidroelektrarne so ključni dejavnik pri proizvodnji električne energije in pri zagotavljanju zanesljivosti delovanja elektroenergetskega sistema. Magistrsko delo je razdeljeno na tri dele, ki se med seboj povezujejo in zaključujejo v enovito celoto. V prvem delu so predstavljene delitve hidroelektrarn, opis delovanja hidroelektrarne, predstavitev glavnih delov, ki sestavljajo hidroelektrarno, predstavitev celotne verige hidroelektrarn na reki Soči z njenimi specifičnimi obratovalnimi posebnostmi. V drugem delu je predstavljen model verige. V tem delu je opisano sestavljanje modela, posamezni deli modela, njegove značilnosti in delovanje. V zadnjem delu je predstavljena validacija modela oziroma primerjava med rezultati iz modela in realnimi podatki, pridobljenimi z meritvami na objektu. V analizi delovanja modela, se je primerjalo vse pomembne dele verige, ki vplivajo na točnost delovanja modela. Analiziralo se je kote bazena v akumulacijah, pretoke vode skozi turbine in dvige spodnje vode pri posameznih HE. Primerjava rezultatov med rezultati modela in realnimi vrednostmi je pokazala zadovoljivo delovanje modela. Večjih odstopanj ni bilo opaziti. Napake so se povečevale, ko je voda potovala proti zadnji HE v verigi, vendar so še vedno bile v dopustnih mejah, ki so omogočale pravilno delovanje modela verige. Hydroelectric power plants are a key factor in the production of electrical energy and ensuring the reliability of the operation of power system. The master's thesis is divided into three parts, which connect each other. The first part presents hydropower plants, a description of the operation of the hydropower plant, the presentation of the main parts of the hydropower plant, the presentation of the entire chain of hydropower plants on the Soča river and its specific operational features. The second part presents the model of the chain of hydropower plants. In this section, we describe how the model is composed, describe the individual parts of the model, its characteristics and operation. The last part presents the validation of the model, the comparison of results from the model and the real data obtained from measurements on the object. In the analysis of the functioning of the model, all relevant parts of the chain were compared, which influence the accuracy of the model's operation. Accumulations, the flows of water through turbines and the rise of the lower water in individual hydropower plant were analysed. Comparison of the results between the results of the model and the real values showed satisfactory operation of the model. No major deviations were observed. The errors increased as the water traveled towards the last of the HPP in the chain, but they were still within the permissible limits that allowed the chain to function properly.

Nemoteno delovanje hidravličnih strojev in naprav ima v industriji posredno velik vpliv na uspešnost poslovanja vsakega posameznega podjetja. Če pride do okvar, je zelo pomembno, da se le te čim hitreje in čim bolje popravijo. Na podobno težavo smo naleteli tudi v našem primeru – v proizvodnji kartona je prišlo do okvare lamelne črpalke s spremenljivo iztisnino. Naša naloga je bila črpalko čim bolje obnoviti in s tem zopet izboljšati njeno delovanje. V diplomski nalogi smo predstavili delovanje črpalke in predstavili njene sestavne dele. Pred obnovo smo izmerili delovne tlake in pretoke ter določili volumetrični izkoristek, ki je bil enak 53 %. S pomočjo analize obrabljenih sestavnih delov smo podali napotke za obnovo in jo tudi izvedli. Po obnovi smo izvedli meritve delovnega tlaka pri obeh možnih stopnjah nastavljanja. Poleg tega smo izvedli tudi meritve pretoka, preko katerega smo določili volumetrični izkoristek obnovljene črpalke. The undisturbed operation of hydraulic machines and devices in the industry has a significant impact on the performance of each individual company. If defects occur, it is very important to repair them as quickly as possible. In the production of the cardboard there was a breakdown of the vane pump with a variable displacement. Our task is to renovate the pump and determine if we have improved it. The diploma task is to learn about the operation and components of the pump. Before the renovation we measured the working pressures and flows and determined the volumetric efficiency, which was equal to 53%. Through the identification of the worn components, we were able to determine the instructions for renewal and to carry out the renovation. After the renovation, we measured the working pressure at the two possible levels of adjustment. We also carried out measurements of the flow through which we determined the volumetric efficiency of the renovated pump.

Ideja dela je spoznati se z osnovnimi pojmi teorije grafov, kot so omrežje, pretok in maksimalni pretok ter predstaviti algoritem potisni-povišaj za iskanje maksimalnega pretoka v omrežju. Algoritem je tudi implementiran, pokazana pa je tudi njegova časovna zahtevnost in pravilnost delovanja. Uporabnost iskanja maksimalnih pretokov je ponazorjena z dvema primeroma iz vsakdanjega življenja. The idea of this work is to get used to basic concepts of graph theory, e.g. network, flow and maximum flow. The core is an explanation of push-relabel algorithm for finding maximum flow through a network. The algorithm is also implemented and its time complexity and correctness are proven. It is also shown with two examples how one can use maximum flows in real life.

Vsak proizvod, v katerem se pretaka medij, mora poleg osnovne funkcije zagotavljati tudi da pretočni medij ne izteka, zato je preizkušanje tesnosti v proizvodnji nujno potrebno. Poznavanje zakonov pretoka tekočin skozi majhne reže je ključno pri izvajanju teh preizkusov. Ker so preizkusi z zrakom stroškovno in praktično bolj učinkoviti kot tisti z vodo, je pomembno poznati relacijo med pretokom obeh medijev pri enakih pogojih. V delu so predstavljene meritve pretoka vode in zraka skozi iglični ventil, ki simulira majhno režo. Določene so tudi vzporednice med pretokom obeh medijev in pojasnjeni parametri, ki vplivajo na velikost pretoka skozi režo. In addition to its basic function, every product that incorporates fluid flow must also ensure that the fluid does not leak out, making leak testing crucial in production.The knowledge of physical phenomena behind fluid flow through a clearance is essential when establishing the fluid-tightness of a product. Since leak testing with air is more cost efficient and practical than using water, the correlation between the flow rate of the two fluids at similar conditions is very important. This paper includes measurements of water and air flow rate through a needle valve, that was used to simulate a small clearance. The parallels between the flow rate of both fluids are established and the factors, that influence the flow rate, are given.

Predpostavimo, da je naš namen prenesti nek material od izvora do ponora preko vozlišč. Na naši poti imamo povezave, ki imajo maksimalno kapaciteto. Naš cilj je ugotoviti, največ koliko materiala lahko prenesemo od izvora do ponora, brez da bi kršili kapacitetne omejitve. Reševanje tega problema je bilo sprva možno s splošnimi tehnikami linearnega programiranja, kasneje pa so se začeli razvijati številni drugi algoritmi. Nekateri izmed njih uporabljajo pristope in metode, ki so zanimivi s teoretičnega vidika, drugi pa so primernejši za uporabo v praksi. Cilji diplomskega dela so predstavitev glavnih idej teh algoritmov, njihova analiza in prikaz nekaterih praktičnih primerov. Želimo ugotoviti, kateri algoritem je trenutno najhitrejši. Let us assume that it is our intention to transfer material from source to sink through the nodes of a graph. Each edge has a certain capacity. Our goal is to determine how much material can be transferred from the source to the sink without violating the capacity limit. Initially basic linear programming techniques were used to solve this problem, but later many other algorithms were discovered. Some of them use approaches and methods that are interesting from a theoretical point of view, while others are more suitable for practical use. The aims of the thesis are the presentation of these algorithms, their analysis and the display of basic examples. We want to figure out which algorithm is currently the fastest in solving this problem.

V diplomskem delu je opisana izdelava kapilarnega merilnika pretoka fluidov. Izdelava merilnika temelji na miniaturni stekleni kapilari, ki je napršena s prevodnim materialom, katerega nadzorovano segrevamo in opazujemo njegovo upornost, ki se spreminja zaradi spremembe pretoka skozi kapilaro. Cilj je izdelati robusten prototip merilnika, ki je učinkovit, kompakten, cenovno ugoden in ima tem večjo ločljivost. V diplomskem delu je poleg opisa izdelave merilnika še zajeten eksperimentalni del. Thesis describes design of capillary flow meter of fluids. Meter design is based on miniature glass capillary, which is sputtered with conductive material, which we controllaby heat and observe it's resistance, which is changing due to fluid flow through capillary. Goal is to create robust prototype of meter, which is effective, compact, affordable and has maximum resolution. Besides production of meter design thesis is describing considerable experimental work.

Diplomsko delo predstavlja teoretične osnove analize krivulj upadanja, katere se uporabljajo za opisovanje dinamike upadanja pretokov. V prvem delu strokovne naloge je predstavljeno teoretično ozadje komponent hidrograma. Predstavljene so tudi metode upadanja pretoka ter nova metoda, s katero dobimo odzivnostno funkcijo porečij, katera odraža odzivnost povodja na spremembe zaloge vode v porečju. V drugem delu je uporabljena nova metoda. Izvedena je analiza na dveh eksperimentalnih porečjih hudournikov Mačkov graben in Kuzlovec, kjer so uporabljeni podatki padavin in pretokov. Naša naloga je bila določiti krivuljo upadanja za oba vodotoka in z oceno le-teh dobiti odzivnostno funkcijo ter ju primerjati. Z novim pristopom ponazorimo, kako lahko uporabimo časovno zaporedje spremenljivosti vodnega toka za razlago povezave med zalogo vode v porečju in pretokom v strugi vodotoka. Prav tako lahko funkciji nadalje uporabimo za karakterizacijo porečja ter za simuliranje celotnega spektra hidroloških pogojev. Še zlasti je nova metoda uporabna za natančnejšo oceno zaloge vode v prispevnem območju, čas upadanja pretoka ter odzivnost porečja na padavine. Graduation thesis presents theoretical basis for classical hydrograph recession curve analysis which are used to describe the dynamics of discharge recession. The first part of the thesis presents theoretical background on assessing different components of hydrographs. A new method which foresees the extraction of catchment sensitivity function is presented. In the second part of the thesis, New method is applied on rainfall and discharge data from two experimental catchments, the Mačkov graben and Kuzlovec torrents. Our task was to determine the periods of discharge recession for both stream, to get sensitivity function and compare them. The new approach demonstrated how streamflow time series can be used to construct a storage–discharge relationship which could be used for catchment characterization and to simulate the entire spectrum of hydrological conditions. In particular, the method leads to possible further quantitative estimates of catchment dynamic storage, recession in different time scales, and sensitivity to rainfall inputs.

V diplomski nalogi je bil na osnovi večletnih meritev pretokov vodomerne postaje Nadvode, 7245 na reki Zrmanji na Hrvaškem izračunan energetski hidropotencial morebitne hidroelektrarne Žegar. Reka Zrmanja je namreč energetsko še neizkoriščena in kot takšna nudi prostor za energetsko izkoriščanje. Trenutni trendi v energetiki dajejo prednost t.i. obnovljivim virom energije. Ljudje so se namreč pričeli zavedati dejstva, da je izkoriščanje fosilnih goriv omejeno in da hkrati s svojo potrošnjo povzročajo velike okoljske rane. Hidroelektrarne kot vir energije pa med svojim obratovanjem v okolje ne oddajajo skoraj nobenih emisij ter ne porabljajo drugih energentov. Tako jih uvrščamo med obnovljive vire. V ta namen je bil preučen hrvaški pravilnik o podporah za energijo, proizvedeno iz obnovljivih virov. Na osnovi geodetskih podatkov je bil modeliran teren v okolici lokacije hidroelektrarne Žegar ter določene glavne tehnične karakteristike elektrarne, ki kakorkoli vplivajo na izračun hidroenergetskega potenciala hidroelektrarne Žegar. Podatki srednjih dnevnih pretokov za obdobje meritev so bili obdelani in ovrednoteni in kot takšni potem upoštevani v preračunu hidroenergetskega potenciala. Hidroenergetski potencial lokacije je bil izračunan za dva tipa hidroelektrarn, in sicer za derivacijsko hidroelektrarno in akumulacijsko hidroelektrarno. Oba potenciala se je medsebojno primerjalo. V nadaljevanju sta bila oba tipa hidroelektrarn ocenjena tudi stroškovno. Na koncu je bila na osnovi predhodno izračunanega hidroenergetskega potenciala opravljena še ekonomska analiza upravičenosti morebitnih investicij v oba tipa hidroelektrarn, in sicer na osnovi letnih prihodkov, odhodkov in sposobnosti vračanja morebitnega kredita za izgradnjo hidroelektrarne. In this thesis, based on measurements of the water flow at the water measurement station Nadvode, 7245 on the Zrmanja river in Croatia, conducted over the course of several years, the energy hydropotential of the potential Žegar hydropower plant was calculated. The Zrmanja river is not yet utilised for harvesting energy and as such offers possibilities for harvesting energy. Current energy trends emphasise to so-called renewable sources of energy. People have become aware of the fact that the utilisation of fossil fuels is limited and that at the same time their consumption causes great harm to the environment. On the other hand, hydropower plants, as a source of energy, emit almost no emissions in the course of their operation and do not consume other energy products. Therefore, they are classified as renewable sources of energy. For this purpose, the Croatian Rules on the Support for Energy Produced by Renewable Sources of Energy have been analysed. Based on geodetic data, a model was made of the terrain in the surrounding area of the Žegar hydropower plant as well as certain main technical characteristics of the power plant, which may in any way affect the calculation of the hydro-energetic potential of the Žegar hydropower plant. Data about the medium daily flows during the period of measurements was processed, evaluated and later considered in the calculation of the hydro-energetic potential. The hydro-energetic potential of the location was calculated for two types of hydropower plants, namely for the derivational hydropower plant and the accumulative hydropower plant. Both potentials have been compared with each other. Later, both types of hydropower plants were cost-assessed as well. Finally, based on the previously calculated hydro-energetic potential, an economic analysis of the feasibility of possible investments in both types of hydropower plant was conducted, this was achieved based on annual revenues, expenditures and the ability to pay back a possible loan for the construction of the hydropower plant.

Diplomska naloga obravnava temo umerjanja računalniškega hidravličnega modela za vodovodni sistem Šmartno ob Paki. V okviru diplomske naloge sem se seznanila z lastnostmi vodovodnega sistema Šmartno ob Paki ter s programsko opremo Aquis, s pomočjo katere sem opravila umerjanje pretoka in tlaka. Vodovodni sistemi predstavljajo dinamičen sistem zgrajen iz več komponent, katere imajo medsebojni vpliv. S pomočjo računalniških programov bolje razumemo statične in dinamične lastnosti vodovodnih sistemov. Pri izdelavi diplomske naloge je bila uporabljena programska oprema Aquis, ki je omogočila spremljanje meritev na sistemu in simulacijo modela. Cilj diplomske naloge je bil primerjati dobljene rezultate simulacije in meritev ter s pomočjo korekcijskega faktorja umeriti model s ciljem povečanja točnosti le-tega. The graduation thesis addresses the subject of calibration of computerized hydraulic model of the pipeline system Šmartno ob Paki. In this thesis I got acquainted with the characteristics of the pipeline system Šmartno ob Paki and software Aquis. With software Aquis I have done the calibration of water flow and pressure. Plumbing systems represent a dynamic system built from multiple components which interact. Computer programs help us to understand better static and dynamic properties of pipeline systems. Software Aquis was used as part of the thesis, with which measurements on the system were monitored and the model simulation was made. The scope of this thesis was to compare the results obtained by simulations and measurements and afterwards to calibrate the model by using the correction factor to increase the accuracy thereof.

V diplomski nalogi so s poenostavljenimi metodami preračunani parametri porušitvenih valov, za izbrane pregrade, za katere obstajajo računi porušitvenih valov s polnimi St.Venant-ovimi enačbami. Na kratko so najprej predstavljene metode in rezultati računov porušitvenih valov s polnimi St. Venantov-imi enačbami za izbrane pregrade, ki bodo služili za nadaljnjo primerjavo. V nadaljevanju je nato opisana poenostavljena metoda za računanje porušitvenih valov. Metoda vsebuje brezdimenzijske koeficiente in dva nomograma, s katerima določimo tri vrednosti. Te vrednosti so največji pretok na pregradi ter čas in razdalja, ko se pretok porušitvenega vala zmanjša na polovično vrednost glede na vrednost največjega pretoka na pregradi ob porušitvi. Pred izračunom so opisane metode in problematika določevanja vhodnih podatkov, ki so potrebni za izračun. V osrednjem delu diplomske naloge so izvedeni izračuni parametrov porušitvenih valov. Rezultate, dobljene s poenostavljenimi metodami, smo primerjali z rezultati, dobljenimi s polnimi St.Venant-ovimi enačbami. Na osnovi opravljene analize odstopanj med obema metodama smo ocenili točnost poenostavljenih metod in njihovo uporabnost za račun porušitvenih valov v hidrotehnični praksi. The thesis uses the simplified methods for calculating the dam-break wave parameters for selected dams, for which the dam-break wave calculations with the full Saint-Venant equations also exist. First, the methods and the results of the dam-break wave calculations with the full Saint-Venant equations for selected dams are briefly presented. They will serve as a basis for further comparison. Then, the simplified method for calculating the dam-break waves is presented. This method contains dimensionless coefficients and two nomograms for determining three values. These values are the maximum flow at the dam, the time, and the distance, when the flow of the dam-break wave is reduced to half the value by reference to the value of the maximum flow at the dam at the time of the dam break. The methods and the problem of determining the input data needed for the calculation are described, followed by the calculation itself. The calculations of the dam-break wave parameters can be found in the main part of the thesis. The results derived from the simplified methods were compared to the results derived from the full Saint-Venant equations. The analysis of the deviations between the methods served as a basis for evaluating the accuracy of the simplified methods and their usefulness in the dam-break wave calculation in the hydraulic engineering practice.

Diplomsko delo obravnava primerjavo armirano – betonskih premostitvenih konstrukcij. Za izbrani primer oz. premostitev smo predstavili tri različne tipe konstrukcij: most, škatlast in cevni prepust. Za vsak primer smo predpostavili enake pogoje, prikazali statični, hidrološki in ekonomski izračun, naredili primerjavo in na podlagi dobljenih rezultatov izbrali optimalen oz. najbolj primeren tip premostitvene konstrukcije. The final thesis deals with the comparison of reinforced concrete bridge structures. For the chosen case we presented three different types of structures: bridge, box and pipe culverts. For each case we have assumed the same conditions and then we have showed static hydrological and economic calculation, made comparison and then based on the obtaiend results we have chosen optimal results obtained or the most suitable type od construction.

Diplomska naloga obravnava zapornice na jezovih hidroelektrarn v Sloveniji. Predstavili smo značilne tipe zapornic in problem vodenja sistema jezu na Nuklearni elektrarni Krško. Podrobno smo predstavili in izračunali pozicije segmentne zapornice in izračunali pretoke vode skozi prelivno polje. This bachelor's thesis discusses floodgates at the hydropower plant dams in Slovenia. The main types of floodgates used and the problem of running the dam system at the Krško Nuclear Plant are studied herein. Special attention has been paid to describing the segment gate, calculating its positions and the water flow rate.

Horizontalne balirke so namenjene baliranju večjih količin odpadnega materiala. Balirke poganja hidravlični sistem, ki mora zagotavljati visoko zmogljivost in potisno silo s čim nižjo pogonsko močjo za pogon dveh glavnih funkcij, to sta predstiskanje s pokrovom in stiskanje z glavnim stiskalnim valjem, ter vračanje obeh v izhodiščni položaj. Da bo zmogljivost balirke čim višja, morata biti ti dve funkciji opravljeni v čim krajšem času. V diplomskem delu so obravnavane različne rešitve hidravličnega dela pogonskih enot in različne rešitve hidravličnega krmilja balirke. Posamezne rešitve so časovno ovrednotene, navedene so prednosti in slabosti posamezne rešitve. Končna rešitev hidravličnega sistema, ki predvideva uporabo regulacijske črpalke, dodatne črpalke s konstantno iztisnino, ter krmilne enote z »varčno« in zaporedno vezavo, je sicer nekaj dražja, a je čas delovanja bistveno krajši od osnovne rešitve. S tem je tudi dosežen osnovni cilj diplomskega dela. Horizontal balers are designed for baling large quantities of waste material. Balers are driven by a hydraulic system, which should provide high performance and thrust with the lowest possible power output to drive the two main functions, i. e. the prepressing with a flap and pressing with the main cylinder, and return both to the starting position. These two main functions should be carried out in the shortest possible time. To have the capacity as high as possible, the two functions should be carried out as quick as possible. Different solutions of hydraulic drive units and different solutions of hydraulic control are shown. Individual solutions are time-evaluated, and the benefits and weaknesses of each solution are stated. The final solution of hydraulic system with variable displacement pump, additional pump with fixed displacement, control unit with "saving" and a series connection is a bit more expensive. However, the operating time is significantly shorter than the basic solution. Thus, the basic goal of the thesis is achieved.

V pričujočem diplomskem delu sem predstavil srednje veliko korporativno računalniško omrežje in problematiko njegove upočasnjenosti, ki je ovirala vsakodnevno delo v podjetju. Analiza prejšnjega stanja je pokazala, da je bil vzrok za pogosto daljše zakasnitve in slabo izkoriščenost internetne povezave preobremenjen robni strežnik. Za uspešno rešitev sem moral premišljeno načrtovati, pripraviti in v omrežje implementirati ustrezen robni strežnik. Pri tem sem s predstavljenimi postopki uspešno odpravil vse težave, omrežje ustrezno optimiziral in hkrati predlagal tudi smernice za dodatne izboljšave v prihodnosti. Primerjava stanja pred posegom in po njem je pokazala, da robni strežnik sedaj omogoča vsaj 10-krat hitrejši pretok in količino podatkovnega prometa s skoraj nespremenjeno porabo sistemskih sredstev, ki je bila pred tem glavni razlog vseh težav. Tako je izkoristek razpoložljive internetne povezave, ki je bil pred optimizacijo manj kot 10-odstoten, sedaj skoraj 100-odstoten. Stabilno delovanje omrežja se kaže tudi s tem, da se je kljub veliko večji obremenitvi omrežja povprečje zakasnitev zmanjšalo za skoraj 30-krat. In this thesis I have presented medium sized corporate network and issues with its slow performance which obstructed company everyday work. Previous state analysis showed that the reason for high latencys and poor network utilization was an overloaded edge server. Successful solution required a thoughtful design, prepararation and implementation of appropriate edge server. With featured procedures I have successfully solved all problems and properly optimized the network. At the same time I suggested further improvement guidelines in the future. State comparison before and after showed that the edge server now allows at least 10-times higher troughput speed and amount of data traffic with almost constant consumption of system resources, that previously caused all main problems. Network utilization is now almost at 100 percent, compared to less then 10 percent in previous state. Stable network performance is also reflected by a 30-times lower average latency despite of much larger network load.

Zadnje stoletje je sladkovodni ekosistem najbolj podvrţen človeškim posegom zaradi izkoriščanja vodne energije. Posledica posegov je, da so številne ribje vrste postale ogroţene in zaščitene z rdečimi seznami ali izginile. Zagotavljanje prehodnosti vodotokov je nujno za prehajanje rib, za ohranjanje ogroţenih in ostalih ribjih populacij. Ribe za svoje ţivljenje potrebujejo različne habitate za drst, rast, prehranjevanje, gibanje. Vsaka neprehodna ovira na vodotokih bi morala imeti urejen naraven, sonaraven ali tehnično grajen ribji prehod. Do izliva v reko Savo ima Ljubljanica kar nekaj neprehodnih ovir, zaradi katerih se je bistveno spremenila kvaliteta habitatov za ribe in tudi za ostale vodne organizme. V okviru projekta Ljubljanica povezuje – Obnovitev koridorja Ljubljanice in izboljšanje rečnega vodnega reţima je bila obnovljena ribja steza ob Plečnikovi zapornici na Ambroţevem trgu. Namen projekta je izboljšati in povezati habitate ciljnih ogroţenih vrst rib v Ljubljanici, to so sulec, platnica in blistavec, ki so zaščiteni z uredbami in pravilniki. V diplomski nalogi je predstavljena problematika prehajanja rib oziroma nefunkcionalnost ribje steze pred obnovo. Povzela sem obnovitvene ukrepe in izboljšave na stezi ter z meritvami pretoka in hitrosti vode na vtoku in v notranjosti ribje steze ugotavljali funkcionalnost le-te. Namen projekta Ljubljanica povezuje je tudi osveščanje ljudi o nujnosti vzpostavitve prehodnosti vodotokov za ribje populacije, tako iz spoštovanja do narave kot z vidika veljavne zakonodaje, ki narekuje obnovitev vseh obstoječih ribjih stez in gradnjo novih na območjih, kjer se bo posegalo v vodotoke. The freshwater ecosystem has mostly been susceptible to human interventions due to the exploitation of hydropower in the last century. The consequences of these interventions are increased numbers of endangered fish species and species categorized by the International Union for Conservation of Nature (IUCN) Red List as likely to become extinct or even extinct species. Ensuring the smooth transfer of watercourse is essential for fish to pass, for conservation of endangered as well as other fish populations. Fish need various habitats for living for example, for spawning, growing, nourishment, movement. Where there is an impassable obstacle in the watercourse, there should be an organised natural or a technically built fish ladder. On the way to the Sava River estuary, there are a few impassable obstacles in the Ljubljanica River and because of that the quality of habitats has changed fundamentally for fish and other water organisms. As a part of the project “Ljubljanica Connects – The Restoration of the Corridor of the Ljubljanica River and the Improvement of the River Regime”, the fish ladder next to the Plečnik sluice at Ambroţ square has been restored. The purpose of the project is to improve and connect the habitats of the endangered species in the Ljubljanica River such as Danube Salmon (Hucho hucho), Danube Roach (Rutilus pigus), Striped Chub (Leuciscus souffia) that is species, protected by regulations. The thesis presents the problem of the migration of fish, or non-functionality of fish ladders before the renewal. Fish had not been able detect the passage. I summed up the renovation measures and the improvements in the fish ladder as well as established the functionality of the ladder with measuring the flow and the speed of the water flow at the entrance as well as in the middle of the fish ladder. The purpose of the project “Ljubljanica Connects” is also to raise awareness among people that the establishment of the smooth transfer of watercourse is essential for fish populations. It is vital we do this out of respect for nature and legislation that dictates the renewal of all the existing fish fishways and the construction of new areas where people will interfere with watercourses.

Diplomska naloga je razdeljena na tri obsežne dele in predstavlja idejni projekt. V prvem delu so opravljeni in predstavljeni hidravlični izračuni reke Savinje skozi Laško za različna stanja. S pomočjo hidravličnih izračunov smo izvedeli, ali so določeni posegi na strugi in izgradnja suhih zadrževalnikov v Spodnji Savinjski dolini smotrni. Na podlagi hidravličnih izračunov smo se v drugem delu usmerili v iskanje območji, kjer reka Savinja prestopi bregove. V drugem delu diplome smo določili tudi potrebne višine in dolžine posameznih odsekov protipoplavnih zidov. V zadnjem delu pa smo poskušali najti ustrezno izvedbo teh protipoplavnih zidov. Klasična izvedba betonskih zidov bi zelo spremenila kakovost življenja v centru Laškega. Lamelna zaščita IBS predstavlja alternativo klasični izvedbi zidov, vendar je njena cena do trikrat višja, hkrati pa se s takšno protipoplavno zaščito obrani center Laškega pred poplavami, kvaliteta življenja prebivalcev pa se ne spremeni. The diploma thesis is divided into three large parts and presents conceptual project. In the first part are carried out and presented hydraulic analyses of the Savinja river through Laško for different conditions. On the basis of hydraulic analyses we have seen, whether certain interventions on the riverbed, and the construction of a dry pond networks in the Lower Savinja valley are rational. Based on the hydraulic analyses in the second part of thesis we focus on finding areas where river Savinja overflows its banks. Also in this part of a thesis we determine the required height and length of the individual sections of flood walls. In the last part we tried to find the proper execution of these flood walls. Classic execution of concrete walls would change the quality of life in the centre of Laško a lot. IBS flood protection system presents an alternative to the classic execution of flood walls, but the price is up to three times higher, at the same time with this flood protection system the centre of Laško is protected from floods, just as well as the quality of life for residents does not change.

Na Univerzitetnem centru za vinogradništvo in vinarstvo Meranovo smo v letih 2007 in 2008 preučevali pretok vode v enoletnih rozgah pri različnih podlagah ('V M', 'SO4', 'Rupestris', 'Binova' in 'Börner') v času mirovanja in solzenja. Pretok vode v rozgah podlag smo merili pri dveh različnih dolžinah (5 in 10 cm). Meritev smo opravili v treh različnih terminih (18. 12. 2007, 12 . 2. 2008, 10. 4. 2008) v času solzenja in mirovanja vinske trte. Pretok vode smo podali v µl na mm² prečnega prereza rozge in površine lesa v eni minuti. Pretok vode posameznih rozg podlag na spodnjem, srednjem in zgornjem nodiju ter na internodiju je bil pri podlagi 'Binova' večji kot pri ostalih podlagah pri drugi meritvi 12. 2. 2008, ko je bila še faza mirovanja. Pri podlagah 'V M', 'SO4', 'Rupestris' in 'Börner' je bil pretok vode večji v času, ko so se že začeli pretakati sokovi. At the Meranovo University Centre for Viticulture and Oenology we studied the water flow in vine canes of different rootstocks ('V M', 'SO4', 'Rupestris', 'Binova' and 'Börner') during the dormant season and lachrymation in 2007 and 2008. We measured the water flow at two different lengths (5 and 10 cm) of the rootstocks canes. Measurements were taken on three different terms (18 December 2007, 12 February 2008, 10 April 2008) during the dormant season and lachrymation of the vine. The water flow is expressed in µl per mm² of transverse section of the vine cane and wood surface in one minute. The water flow at the lower, middle and upper nodes and the internode of the vine canes was higher in the 'Binova' rootstock than in the other rootstocks when the second measurement was taken during the dormant season on 12 February 2008. In the 'V M', 'SO4', 'Rupestris' and 'Börner' rootstocks, the water flow was highest when the sap started to flow.

Diplomska naloga obravnava obstojece stanje prikljuckov in obmocij vkljucevanj na avtoceste in hitre ceste, predvsem na ljubljanskem AC in HC obrocu, ki je eden najbolj obremenjenih in zahtevnih cestnih sistemov v državi. V zacetnem delu naloge so opisana obravnavana obmocja. Natancneje so predstavljena obmocja ramp in obmocja prepletanja ter osnovni tehnicni predpisi, ki so trenutno v veljavi. V empiricnem delu sledi obravnava konkretnega primera, kjer je bila spremenjena prometna ureditev in so bile izvedene dolocene izboljšave, ki so se izkazale za uspešne. To je potrjuje tudi podrobnejša obdelava prometnih podatkov, ki so bili pridobljeni iz avtomatskih števcev in s pomocjo rocnega štetja, ter predstavitev primerjave diagramov prometnega toka pred in po spremembi prometne ureditve obravnavanega odseka. V nadaljevanju je predstavljen odsek med prikljuckoma Lj. Šentjakob in Lj. Sneberje, ki še caka na takšno spremembo. Tudi na tem mestu je bilo opravljeno rocno štetje, s katerim so bili pridobljeni podatki, ki so kasneje uporabljeni v programski analizi. Ta dokazuje, da bi bilo tudi na tem odseku priporocljivo izvesti podoben ukrep. V zadnjem delu je predstavljenih še nekaj problematicnih odsekov na ljubljanski obvoznici in drugod po Sloveniji z navedenimi konkretnimi predlogi in rešitvami za odpravo nastale problematike. The thesis deals with the present condition of junctions and appertaining areas of freeways and motorways, especially of Ljubljana AC and HC ring, which is one of the busiest and most demanding parts of Slovenian road system. The theoretical part of the thesis discusses the teory of trafic flow, which is a basis for the understanding of subsequent subjects. The areas of ramps, weaving and basic technical regulations are dealt with in detail. The second part deals with a specific case of altered traffic arrangement with some effective improvements, proven by a detailed analysis of trafic data obtained from automatic gauges and by manual counting, as well as the comparison between the diagrams of traffic flow before and after the alteration of the road section in question. Furthermore, the section between the junctions Lj. Šentjakob and Lj. Sneberje, which is still to be altered in this way, is presented. Manual counting has been carried out here as well and the data have been used in programme analysis. It has been proven that a similar measure should be taken in this section, too. The last part presents a few other problematic section of Ljubljana ring road and elsewhere in Slovenia, suggesting measures to solve them.

V zadnjih desetletjih se vse pogosteje soočamo s številnimi hidrološkimi problemi, ki predstavljajo velik izziv in preizkušnjo za človeštvo. Danes je potreba po orodjih, ki izvajajo kompleksnejše analize hidrološkega režima, izredno velika, saj se lahko le z ustreznim preučevanjem, predvidevanjem in napovedovanjem možnih ekstremnih dogodkov nanje delno pripravimo in učinkovito izvajamo ukrepe za zaščito. Poznavanje soodvisnosti pretok – trajanje – verjetnost omogoča kompleksnejšo verjetnostno analizo, ki celoviteje opredeli pojave in vplive različnih posegov na pojave. Verjetnostna analiza pretočnih volumnov vključuje klasično verjetnostno analizo pretokov znotraj vsakega niza z določenim trajanjem. Povprečni pretoki so najprej izračunani na podlagi različnih stalnih trajanj. Nato pa je za vsako trajanje izvedena verjetnostna analiza letnih maksimalnih (minimalnih) pretokov z izbrano teoretično porazdelitvijo. V diplomski nalogi smo s programom HEC-SSP izvedli verjetnostno analizo pretočnih volumnov na vodomernih postajah v Sloveniji. Na primeru vodomerne postaje Jesenice na reki Savi Dolinki je prikazan celoten potek tovrstne verjetnostne analize, katere rezultate smo v zadnjem delu naloge uporabili na primeru akumulacijskega bazena HE Moste. Poskušali smo prikazati, kako z zadrževanjem maksimalnih pretokov različnih trajanj vplivamo na zmanjšanje pretokov dolvodno od pregrade, ter določili potrebni zadrževalni volumen akumulacije pri danem maksimalnem pretočnem volumnu in ob upoštevanju obratovalnega instaliranega in doinstaliranega pretoka hidroelektrarne Moste. In recent decades we are increasingly facing with many hydrological problems that pose a great challenge and test for humanity. Today, there is a significant need for tools that perform complex analysis of the hydrological regime. On the possible extreme events can be partially prepared and we can effectively implement measures to protect only through adequate studying, predicting and forecasting them. Knowing the interdependence of flow – duration – frequency allows more complex frequency analysis, which comprehensively defines the occurrence and impact of different interventions on the phenomena. Volume frequency analysis involves classic frequency analysis of maximum (minimum) flow within each of a set of specified durations. Average flow rates are first calculated based on different fixed durations. Then, for each duration frequency analysis of maximum (minimum) flow is performed with selected theoretical distribution. In the thesis we performed volume frequency analysis with HEC – SSP software for gauging stations in Slovenia. The entire course of volume frequency analysis is shown for gauging station Jesenice on the river Sava Dolinka. The results were used for the case of the reservoir HPP Moste, where we tried to show how the containment of flood flows with different durations influence on reducing the flow downstream of the barrier. We also determined the necessary containment volume of the reservoir for a given maximum inflow volume and the operational installed flow of the HPP Moste.

V diplomski nalogi smo izvedli oceno potenciala za proizvodnjo električne energije na manjšem potoku, Pendijevki na porečju reke Krke lociranem na pobočju Gorjancev. Oceno smo izvedli na odseku med dvema obstoječima prodnima pregradama. Ker hidrološki podatki za ta odsek niso bili na voljo smo najprej naredili preveritev karakterističnih pretokov z uporabo empiričnih enačb in jih primerjali s sosednjim porečjem za katerega smo imeli na voljo dolgoletni niz povprečnih dnevnih pretokov. Na osnovi potrditve podobnosti med porečjema smo določili niz povprečnih dnevnih pretokov v obravnavanem obdobju za Pendirjevko. V naslednjem koraku smo določili razpoložljive dnevne pretoke, ki jih lahko izkoristimo za energetsko rabo in na osnovi izbranega instaliranega pretoka turbin določili energetske karakteristike hidroelelktrarne. Instaliran pretok smo povečevali postopoma in vsakič izračunali proizvedeno energijo ter prihodek proizvedene energije. Na ta način smo določili optimalni instalirani pretok in karakteristike elektrarne za katerega je investicija ekonomsko upravičljiva. In this dissertation we evaluated the potential for generating electrical energy on a smaller stream, Pendirjevka, within the Krka river basin located on the Gorjanci hillside. The estimate was made on a section between two gravel barriers. Since the hydrologic data for this section were not available, we first checked the characteristical flows using empyrical formulas and then compared them with those of an adjacent river basin, whose long-time series of average daily flows were accessible. Based on the confirmation of the two basins being similar, we determined the series of Pendirjevka's average daily flows in the discussed period. The next step consisted of determining the available daily flows which can be exploited for energy purposes and determining the energy characteristics of the hydroelectric power station based on the chosen installed flow of the turbine. We gradually increased the installed flow and each time calculated the produced energy and its earnings. By doing so we determined the optimum installed flow and the characteristics of a power station for which an investment is economically legitimate.

Natančnost merjenja merilnih instrumentov je zelo pomembna pri spremljanju dobavljenih količin, kajti le z zagotavljanjem ustrezne natančnosti lahko zagotovimo željeno kakovost v procesnih sistemih ali pri distribuciji. V diplomskem delu predstavljam avtomatizacijo postopka umerjanja merilnih instrumentov za merjenje pretoka plinov, prvenstveno komprimiranega zraka. Na obstoječi sistem cevi (pogonskega sistema s puhalom in motorjem, ki ga poganja pogon s frekvenčno regulacijo) smo dodali prograbilni logični krmilnik za krmiljenje pogona in pretvorbo analognih signalov v digitalne in obratno. Nadzor nad stanjem delovanja in samodejno računalniško obdelavo parametrov smo izvedli s pomočjo po meri napisanega programa v sistemu SCADA. Rezultati kažejo, da avtomatizacija postopka zagotavlja sistematičnost, hitrejše in enostavnejše izvajanje, boljšo natančnost storitve. The accuracy of measuring instruments is of vital importance when monitoring the supplied quantities, as solely by assuring the required accuracy, required quality of service in the process systems and distribution can be achieved. The following thesis represents the automation of the process of calibration of gas flow meters, which in our case are mostly compressed air flow meters. By upgrading the existing pipe system and blower (driven by a motor with variable frequency drive) with a programmable logic controller that is also used as an analog to digital converter and vice versa, and by using the program in SCADA system to monitor operations and automation of data processing, we managed to obtain a higher accuracy of calibration. The results also show that the automation of this process makes the process more accurate, faster and simpler for the operator to perform.