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The Fuel Cells and Hydrogen (FCH) technologies will play an important role in a future where greenhouse gasses emissions need to be reduced. Nevertheless, a huge implementation of these technologies must be addressed taking into account an eco friendly scope not only from the manufacturing perspective but also from the end-of-life scope. A classification of the materials has been done considering the importance of each of them. To obtain a complete overview of the problem, different criteria have been compared: the cost, the scarcity of the material and the affections these materials can cause not only to the environment but also to the humans. This classification has been used to identify which are the most critical materials. Moreover, other transversal issues have been studied as the regulations that apply to FCH technologies from a paneuropean perspective and the strategies to face the end-of-life of this equipment. A holistic point of view has been considered in order to see how the process of dismantling and recycling faces different problems and which milestones to achieve in a future with a deep market penetration are.

In this paper we present a numerical approach to determining the variation of rotational speed with the convective heat transfer of blade structures. The investigated structure, which is cooled by air, was subjected to an axial hot-air stream in a cross-flow system. In order to exclude the influence of undesirable, aerodynamic flow forces, a simplified geometry was chosen, and the influence of varying the rotational speed was studied. The distributions of heat-transfer rate on the hot side of the structure's wall were determined with CFD calculations. The non-uniformity of the heat transfer increased with the rotational speed due to the increasing impact of centrifugal flow forces on the boundary-layer thickness. The impact of rotational speed on the heat-transfer rate was found not to be significant. The results of the studiedstructure were also used to validate various one-dimensional, empirical, convective heat-transfer models that are commonly applied in engineering practice. In all cases, the flat-wall heat-transfer treatment showed the best agreement with the results of the CFD calculations. V prispevku je obravnavana odvisnost konvektivnega prenosa toplote od vrtilne frekvence na vroči steni turbinske lopatice. Prenos toplote poteka v kriznem sistemu iz aksialnega toka vroeih dimnih plinov na hladilni zrak v kanalu lopatice. Z numeričnim modelom smo simulirali tokovne in energijske razmere v aksialni krožni kaskadi z ravnimi lopaticami pri različnih vrtilnih frekvencah in količini hladilnega zraka, rezultate pa smo zapisali v brezdimenzijski obliki. Izkazalo se je, da ima v obravnavanem primeru razmernik hladilnega zraka bistveno večji vpliv od rotacijskega števila. Rezultate numeričnih simulacij smo primerjali z rezultati enodimenzijskih, polizkustvenih modelov konvektivnega prenosa toplote z različnimi nastavki, ki so v praksi najpogosteje uporabljeni. V primerjavi z rezultati numeričnih analiz vsi trije uporabljeni modeli kazejo pravilno usmeritev, naboljse ujemanje pa dobimo z uporabo modela prenosa toplote skozi ravno steno.

Tematika magistrske naloge obravnava koncept blaženja hipotetične nezgode izgube hlajenja v eni izmed primarnih komponent demonstracijskega fuzijskega reaktorja DEMO. V tem oziru so najbolj kritične notranje komponente tokamaka, ki so v neposredni bližini plazme, npr. oplodna obloga (ang. Breeding blanket). Med obratovanjem reaktorja se zaradi izpostavljenosti visokim nevtronskim fluksom oplodna obloga močno segreva, z aktivnim sistemom hladilnih kanalov akumulirano toploto sproti odvajamo in tako vzdržujemo primerno temperaturo obloge. V primeru izgube aktivnega hlajenja začne temperatura prizadetega dela obloge, kljub takojšnji zaustavitvi fuzijske reakcije, naraščati zaradi zaostale toplote v aktiviranih materialih. Zato razvoj konceptne zasnove fuzijskega reaktorja DEMO obravnava tudi zasnovo potencialnih metod blaženja posledic tovrstnih nezgod, ki bi lahko učinkovito zmanjšale poškodbe reaktorja in čas zaustavitve zaradi popravil. V nalogi smo prikazali potek določanja ustrezne velikosti šob hladilnega sistema. Do rezultatov smo prišli z uporabo 0D-modela, ki smo ga na koncu preverili še z uporabo 3D-modela v programu Ansys Fluent. Ugotovili smo, da z uporabo 0D-modela velikost šobe določimo dovolj natančno in s precej krajšimi računskimi časi. The purpose of this master’s thesis is to investigate the concept for mitigation of a potential loss of cooling accident, caused by a total loss of cooling in one of the primal components of the demonstrational fusion reactor DEMO. In this regard, the most critical components are the ones inside the tokamak, such as the Breeding Blanket. When the reactor is in operation, in-vessel components heat up significantly due to an exposure to high neutron fluxes. This accumulated heat can be removed with an active cooling system, which ensures that an appropriate temperature of the Breeding Blankets is maintained. In the case of the loss of active cooling, despite immediate shut down of a fusion reaction, the temperature of the affected components (e.g. Breeding Blankets) starts to rise due to the internal heat generation by decay heat. Thus the development of the conceptual DEMO design also addresses the mitigation concepts for potential accidents to effectively reduce the damage of the reactor and to shorten the outage time. The aim of this research was to calculate the diameter of cooling system nozzles. The diameter was determined using a 0D model, which was later checked by a 3D model in Ansys Fluent program. It was concluded that using a 0D model the results are accurate enough and require much less computation time.

V okviru zaključne naloge smo obravnavali delovanje centrifugalnih vodnih črpalk v okviru laboratorijske merilne postaje na Fakulteti za strojništvo, ki omogoča analizo delovanja črpalk v različnih režimih delovanja. Glavni cilj je bil obnoviti in nadgraditi merilno postajo ter vzpostaviti merilni sistem za zajem obratovalnih veličin in analizo karakteristik. Prvi del naloge je bil zato usmerjen v analizo trenutnega stanja. Glede na dotrajanost določenih delov merilne postaje smo izvedli zamenjavo regulacijskega ventila in nadgradili sistem za zajem in obdelavo izmerjenih veličin. V programskem okolju LabView smo vzpostavili okolje za zajem in obdelavo podatkov ter analizo karakteristik črpalk in cevovoda. V drugem delu naloge smo izvedli preizkuse ob različnih vezavah ene in/ali dveh centrifugalnih črpalk. Na podlagi meritev smo izračunali volumski pretok, dobavno višino, izkoristek in teoretično moč. Izrisali smo graf odvisnosti dobavne višine od pretoka, kar predstavlja osnovno karakteristiko centrifugalne črpalke. Na podlagi izmerjene potrebne električne moči smo dodatno, v vseh obratovalnih točkah izračunali energijski izkoristek centrifugalnih črpalk. Na podlagi dobljenih rezultatov lahko zaključimo, da je bila nadgradnja merilne postaje uspešna, saj nadgrajeni merilni sistem deluje pravilno, rezultati pa so v okviru pričakovanih vrednosti. The final thesis looked at the performance of centrifugal water pumps in the context of a laboratory metering station, which allows the analysis of the performance of pumps in different operating regimes. The main objective was to refurbish and upgrade the measurement station and to set up a measurement system for the acquisition of operating quantities and the analysis of the characteristics. The first part of the task focused on the analysis of the current situation. The control valve was replaced and the system for the acquisition and processing of measured values was upgraded. In the LabView software environment, we set up an environment for data acquisition and processing, as well as for the analysis of the pump and pipeline characteristics. In the second part of the task, tests were carried out with different couplings of one and/or two centrifugal pumps. Based on the measurements, we calculated the volumetric flow rate, delivery height, efficiency, and the theoretical power. We have plotted a graph of the dependence of the delivery head on the volumetric flow, which represents the basic characteristic of a centrifugal pump. Additionally, the energy efficiency of the centrifugal pumps has been calculated at all operating points based on the measured electrical power required. Based on the results, it can be concluded that the upgrade of the metering station has been successful, as the upgraded metering system is working correctly, and the results are within the expected values.

V današnjem času se zaradi napredne tehnologije povečuje potreba po energiji. Stari načini pridobivanja energije predstavljajo umazano industrijo, katera v današnjem svetu ni več primerna. Prav zato se trudimo tradicionalne načine proizvajanja elektrike zamenjati s tako imenovano zeleno energijo. Zato smo se odločili raziskati zelene tehnologije, katere so nas privedle do raziskovanja vodikovih tehnologij, natančneje tehnologije elektrolizerjev in vodikovih gorivnih celic, ki nam omogočajo proizvodnjo in uporabo zelenega vodika. Raziskali smo, kaj vodikove tehnologije predstavljajo kot tehnologija prihodnosti in opravili smo preizkus, ki je preveril pomembnost digitalizacije. Today, advanced technology is increasing the need for energy. The old ways of generating energy represent a dirty industry that is no longer suitable in today's world. That's why we are trying to replace traditional ways of generating electricity with so-called green energy. This is why we decided to explore green technologies, which led us to explore hydrogen technologies, more specifically electrolysers and also hydrogen fuel cell , which enable us to produce and use green hydrogen. We explored what hydrogen technologies represent as the technology of the future and ran a test to verify the importance of digitalization.

Vsebina naloge je izdelava energijskih in ekonomskih bilanc projekta postavitve vetrne elektrarne in analiza okoljskih kazalnikov uporabe tovrstne tehnologije. Za izbran tip vetrne elektrarne smo določili kraj postavitve ter izračunali količino proizvedene električne energije na dnevnem in letnem nivoju, izkoristek pretvorbe vetra v električno energijo in doseganje Betzove meje. Pri tem smo uporabili javno dostopne podatke spletne strani renewables.ninja. Na podlagi energijske bilance smo izdelali ekonomsko analizo projekta. Z upoštevanjem prihodkov od prodaje električne energije, višine investicije, vzdrževalnih in obratovalnih stroškov ter stroškov razgradnje, smo s pomočjo ekonomskih kazalnikov projekt opredelili kot ekonomsko neupravičenega. Z uporabo hierarhičnega modela metode ReCiPe smo izdelali okoljsko analizo (LCA) vetrnih elektrarn. Okoljske kazalnike vetrne elektrarne, postavljene v Sloveniji, smo primerjali z okoljskimi kazalniki vetrnih elektrarn v nekaj izbranih evropskih državah. Prav tako smo jih primerjali z nekaterimi drugimi tehnologijami proizvodnje električne energije, katere se uporabljajo v Sloveniji. The purpose of this paper is energy and economic calculations of the wind farm project and analysis of the environmental impact for this type of technology. For the selected type of wind farm, we have determined the location and calculated the amount of electricity generated on a daily and annual basis, the efficiency of converting wind energy into electricity and reaching the Betz limit. For calculations we used publicly available data from website renewables.ninja. Based on the energy data, economic analysis of the project was carried out. Considering revenues from electricity sales, investment costs, maintenance and operational costs, and decommissioning costs, we identified the project as economically ineligible. Using the ReCiPe hierarchist model, we carried out environmental analysis (LCA) of wind farms. The environmental indicators of a wind farm installed in Slovenia were compared with the indicators of wind farms in selected European countries. We also compared them with some other electricity generation technologies used in Slovenia.

V magistrskem delu smo obravnavali ogljični odtis podjetja, pri čemer so vsi robni pogoji in inventar definirani glede na realne podatke srednje velikega podjetja. Za izračun ogljičnega odtisa smo uporabili standardizirano metodologijo GHG Protocola, ki toplogredne vire emisij deli na tri obsege, ki predstavljajo neposredne in posredne okoljske vplive. Največji vpliv v obsegu 1, ki predstavlja neposredne emisije toplogrednih plinov, predstavlja uporaba osebnih avtomobilov. Toplota predstavlja največji vir toplogrednih plinov v obsegu 2, ki zajema električno energijo in toploto. V okviru obsega 3, v katerega sodijo preostale posredne emisije, je največji vir material, ki ga podjetje uporablja za izdelavo osnovnih proizvodov. V sklepnem delu naloge smo naredili analizo vplivnih parametrov, kjer primerjamo vplive devetih različnih parametrov in analizirali njihov vpliv na celoten ogljični odtis podjetja in trajnostni razvoj. Scenariji predstavljajo različne aktivnosti, ki jih podjetje lahko implementira z namenom zmanjšanja ogljičnega odtisa. Podjetje lahko doseže največja zmanjšanja s pridobivanjem toplote iz peči na biomaso. Z implementacijo aktivnosti alternativnih poti zaposlenih na delo in nazaj, dosežemo največje zmanjšanje v obsegu 3. Znotraj obsega 1 pa lahko podjetje doseže največje zmanjšanje z elektrifikacijo osebnih avtomobilov, pri predpostavki uporabe nizko-ogljične električne energije. In the master's thesis, we discussed the carbon footprint of the company, where all boundary conditions and inventory are defined according to the real data of a medium-sized company. To calculate the carbon footprint, we used the standardized methodology of the GHG Protocol, which divides greenhouse gas emission sources into three scopes, which represent direct and indirect environmental impacts. The biggest impact in scope 1, which represents direct greenhouse gas emissions, is the use of passenger cars. Heat is the largest source of greenhouse gases in scope 2, which includes electricity and heat. Within scope 3, which includes all other indirect emissions, the largest source is the material used by the company to manufacture basic products. In the concluding part of the thesis, we made an analysis of impact parameters, where we compare the impacts of nine different parameters and analyze their impact on the overall carbon footprint of the company and sustainable development. Scenarios represent various activities that a company can implement to reduce its carbon footprint. The company can reduce its carbon footprint by the largest amount by extracting heat from biomass furnaces. By implementing alternative types of employee commuting, we achieve the largest reduction in scope 3. Within scope 1, the company can achieve the largest reduction by electrification of passenger cars, assuming the use of low-carbon electricity.

V diplomski nalogi smo s pomočjo študije življenjskih ciklov ovrednotili okoljske vplive proizvodnje 1 kilograma vodika. Za vrednotenje okoljskih vplivov smo uporabil program GaBi. Z uporabo okoljskih kazalcev metodologije Environmental Footprint - EF 3.0 smo določili, katere tehnologije proizvodnje vodika imajo večji vpliv na okolje ter katere tehnologije so najbolj prijazne okolju. Najčistejši izmed vseh načinov proizvodnje vodika je vodik, ki nastaja kot stranski produkt pri proizvodnji kloroalkalnih snovi. Temu načinu proizvodnje vodika sledi vodik, ki je proizveden s tehnologijo krekinga in vodik proizveden z parnim reformiranjem zemeljskega plina. Največji vpliv na okolje ima vodik, ki je pridobljen z elektrolizo vode, kjer je vhodna električna energija pridobljena pretežno iz jedrskih, hidro in termo elektrarn. In this thesis we analysed environmental impacts of producing 1 kg of hydrogen. We did it using life cycle assessment. We used GaBi software for evaluating environmental impacts. With usage of environmental indicators from methodology Environmental Footprint – EF 3.0 we defined which hydrogen production technologies have the biggest and which the smallest impact on the environment. The cleanest hydrogen is the one produced as a by-product from chlor-alkali production. Hydrogen produced with cracking and steam reforming of natural gas follows. The biggest impact on the environment has electrolysis of water, in which the input electric energy is produced mainly from nuclear, hydro and thermal power plants.

Potrebe po energiji naraščajo, hkrati pa ostaja težnja po uporabi zelenih virov energije. Vodikove tehnologije ponujajo številne prednosti in se v tem trenutku zdijo primerna rešitev za zadostitev okoljskih zahtev. V nalogi so pregledane aktualne tehnologije elektrolizerjev, na podlagi katerih so postavljeni numerični modeli za študijo življenjskih ciklov posameznih tehnologij in njihova medsebojna primerjava okoljskih vplivov ob proizvodnji 1 kg vodika z uporabo električne energije iz virov v Sloveniji. Ugotovljeno je bilo, da je faza obratovanja elektrolizerjev bistvenega pomena iz vidika okoljskih vplivov, ter da je izbira vira električne energije odločujoča. Najbolj smiseln vir za napajanje elektrolizerja je hidro energija, medtem ko ni smiselno uporabljati slovenske energijske mešanice. The needs for energy are growing, but a tendency to use green energy sources is the same. Hydrogen technologies offer many advantages and so far seem to be a suitable solution to meet environmental requirements. This work examines current technologies of electrolysers, based on which numerical models for life cycle assessment of individual technologies are set up. A mutual comparison between technologies is made regarding production of 1 kg of hydrogen. It was found that the operation phase of electrolysers is the most critical from the point of view of environmental impacts, and that the choice of Slovenian energy source is decisive. The most sensible source to power an electrolyzer is hydro energy, while it does not make sense to use a Slovenian energy mix.

Večina današnjih umetnih svetil za svoje delovanje izkorišča električno energijo. Med njimi sta eni izmed najbolj prepoznavnih zagotovo žarnica z žarilno nitko in LED sijalka, ki imata zaradi svoje različne sestave in lastnosti, povsem drugačne vplive na okolje. Te vplive smo analizirali s pomočjo metode imenovane študija življenjskih ciklov - LCA. S pomočjo programa GaBi smo izdelali potrebne LCA modele, katere smo analizirali s pomočjo metode CML 2001 v obliki 11 okoljskih indikatorjev. Pri večini indikatorjev ima največji vpliv žarnica z žarilno nitko, kjer je glavni razlog, vedno predstavljala faza uporabe. Pri potencialu globalnega segrevanja je doprinos toplogrednih plinov od žarnice z žarilno nitko 9-krat večji kot pri LED sijalki. Pri ostalih indikatorjih, kot je na primer potencial toksičnosti za človeka, ima višje vrednosti LED sijalka, pri kateri so imele ključno vlogo pri vplivih na okolje, predhodno izdelane elektrotehniške komponente in kritični materiali v njih. Dodatno smo ločeno primerjali še fazo proizvodnje, kjer je razviden veliko večji vpliv LED sijalke na okolje, katere vrednosti so močno presegale tiste od žarnice z žarilno nitko. Moramo pa se zavedati, da je za celovito sklepanje o tem katero svetilo ima večje vplive na okolje, potrebna še analiza zaključka življenjskega cikla, katero bo verjeno bolj obremenila LED sijalka, kot žarnica z žarilno nitko. Most of nowadays artificial illuminates use electricity for their operation. Among them there are two which are probably the most recognizable. First is an incandescent lamp and second is a LED lamp, which have completely different environmental impacts due to their different composition and properties. These impacts were analysed using the life cycle assessment method. With the help of the GaBi program, we created the necessary LCA models, which we analysed using the CML 2001 method in a form of 11 environmental indicators. For most indicators, the incandescent lamp has the greatest impact. The main reason for the increased values of the indicators has always been the use phase. For the global warming potential, the contribution of greenhouse gases from an incandescent lamp is 9 times greater than that of a LED lamp. For other indicators, such as the potential for toxicity to humans, different prefabricated electrical components contributed the most. Additionally, we separately compared the manufacturing phases of both lamps. The result was that a LED lamp has a much greater environmental impact because the values of a LED lamp far exceed those of the incandescent lamp. However, we need to be aware that a holistic conclusion about which illuminate has a greater environmental impact, requires an additional analysis of a end of life phase, which will probably be more effected by LED lamp rather than incandescent lamp.

Ko govorimo o prihodnosti pridobivanja električne energije in o ogljični neodvisnosti, je zelena energija pomembna tema. Vodik velja kot rešitev, težava pa nastane pri proizvodnji vodika s pomočjo obstoječih virov energije. Vplive na okolje zaradi proizvodnje vodika bomo ocenili s pomočjo študije življenjskih ciklov (LCA), pri tem pa bomo upoštevali slovensko mešanico pridobivanja el. energije, samo hidroelektrarne in samo jedrsko elektrarno. Rezultate bomo prikazali za proizvodnjo 1 kg vodika. Programsko orodje, ki ga bomo uporabili za izdelavo modela, je GaBi Thinkstep, ocena za prikaz okoljskih vplivov pa je metoda Environmental Footprint – EF (3.0). Rezultati so pokazali, da ima najnižje vrednosti okoljskih indikatorjev NEK, za tem hidroelektrarna, najslabše pa ima slovenska energijska mešanica, kar je logično, saj je v to vključena tudi uporaba termoelektrarn, ki za gorivo uporabljajo premog. Ugotovili smo, da pridelava vodika s trenutno slovensko mešanico z vidika okoljskih vplivov ni posebno zelena. Večino onesnaževanja povzroča elektroliza. Okoljske kazalce bi močno znižali z izgradnjo drugega bloka jedrske elektrarne. When we talk about the future of electricity generation and carbon independence, green energy is an important topic. Hydrogen is considered a solution, and the problem arises in the production of hydrogen using existing energy sources. Environmental impacts due to hydrogen production will be assessed using a life cycle study (LCA), considering the Slovenian mixture of electricity generation hydropower and nuclear power. The results will be shown fort the production of 1 kg of hydrogen. The software tool we will use to create the model is GaBi Thinkstep, and the assessment to show environmental impacts is the Environmental Footprint – EF (3.0) method. The results showed that the Krško nuclear power plant has the lowest values of environmental indicators, followed by a hydroelectric power plant, and the Slovenian energy mix has the worst, which is logical, since this also includes the use of thermal power plants that use coal as fuel. We found that the production of hydrogen with the current Slovenian mixture is not particularly green in terms of environmental impacts. Most of the pollution is caused by the electrolysis process.

Oskrba z električno energijo je kompleksen proces, ki zajema različne tehnologije proizvodnje električne energije in distribucijo do porabnikov. Tehnologije za proizvodnjo el. energije porabljajo različne energente in imajo zato drugačne vplive na okolje. Za oceno vplivov na okolje smo uporabili metodo študije življenjskih ciklov (LCA) in ovrednotili enajst tehnologij, ki se uporabljajo v Sloveniji, pri čemer funkcionalno enoto predstavlja 1kWh električne energije pri končnem porabniku. LCA model smo postavili v programu GaBi Thinkstep, oceno rezultatov na ravni okoljskih indikatorjev pa smo opravili po metodi ReCiPe. Najnižje vrednosti okoljskih indikatorjev imajo hidroelektrarne in vetrne elektrarne. Nizke vrednosti so še pri jedrski elektrarni, fotovoltaiki in zemeljskemu plinu. V povprečju dva do petkrat višje vrednosti so pri termoelektrarnah na lignit, črni premog, biomaso in odpadke. Najvišje vrednosti pa so bile pri težkem kurilnem olju in bioplinu. Dodatno smo analizirali okoljske vplive štirih scenarijev proizvodnje električne energije za Slovenijo, ki se nanašajo na zapiranje TEŠ-a, postavitev drugega bloka jedrske elektrarne in na prehajanje proti 100% deležu obnovljivih virov energije. Ugotovili smo, da prehod na obnovljive vire, v primerjavi z obstoječo energijsko mešanico, za polovico zniža vrednost indikatorja podnebnih sprememb, se pa močno povečajo toksičnost, evtrofikacija, zakiseljevanje, raba zemlje in tanjšanje ozonske plasti. Z drugim blokom jedrske elektrarne pa bi večina indikatorjev imela nižje vrednosti. Electricity supply is a complex process involving various technologies of electricity generation and distribution. Electricity production technologies use different energy sources and therefore have different impacts on the environment. To assess the impact on the environment, we used the life cycle study (LCA) method and evaluated eleven technologies used in Slovenia. The functional unit is set at 1kWh of electricity at the consumer. The LCA model was set up in the GaBi Thinkstep program, and the evaluation of the results based on environmental indicators was performed according to the ReCiPe methodology. Hydropower and wind power plants have the lowest values of environmental indicators. Nuclear power plants, photovoltaics and natural gas also show lower values. On average, two to five times, higher values for environmental indicators are observed for thermal power plants on lignite, hard coal, biomass, and waste. The highest values were for heavy fuel oil and biogas electricity production. We additionally analysed the environmental impacts of four scenarios of electricity production in Slovenia, which relate to the closure of thermal power plant TEŠ, the construction of the second unit of the nuclear power plant Krško and the transition to renewable resources. We found that transition to renewables, compared to the existing energy mix, halves the value of climate change indicator, but significantly increases toxicity, eutrophication, acidification, land use and ozone depletion. With the second block of the nuclear power plant, however, most indicators would have lower values.

V diplomskem delu smo predstavili vodikove tehnologije, podrobneje pogledali gorivno celico s protonsko prepustno membrano in njeno prenapetostno krivuljo. Predstavili smo tudi teorijo gorivnih celic in njihovo delovanje. Diplomsko delo temelji na eksperimentalnem delu merjenja prenapetostne krivulje gorivne celice na merilni progi. Na osnovi izmerjenih rezultatov eksperimenta smo izrisali prenapetostno krivuljo, krivuljo električne moči in električnega izkoristka. Rezultati kažejo pravo izbiro razmerij plinov in izbranih pogojev za učinkovito delovanje gorivne celice. Prikazana je primerjava rezultatov različnih meritev, kjer vidimo odstopanja od pričakovanj in smernice za natančnejše določanje razmerij plinov in fizikalnih količin. Podani so tudi napotki za izboljšavo merilnega sistema. In the thesis hydrogen technologies and particularly the proton-exchange membrane fuel cell was studied. The polarization curve of fuel cell was determined using experimental approach. Fuel cell theory of most frequently used fuel cells was presented and basic characteristics of these fuel cells exposed. The thesis is oriented in experimental approach of measuring the polarization curve of the fuel cell on experimental rig. Based on the results of the experiment, we constructed the polarization curve, the power curve and the efficiency curve. The results show the right selection of gases ratio and specific selected conditions for efficient operation of the fuel cell. The comparison of results of different measurements is presented and we can see the deviations from the expected results. From results we can give basic guidelines for more accurate determination of gas ratios and other physical quantities. Suggestions for the improvement of the measuring system are also provided.

V zaključni nalogi so obravnavane emisije ogljikovega dioksida specifičnega električnega vozila kot posledica vseh faz življenjske dobe vozila (brez upoštevanja reciklaže). Uporabljena metodologija temelji na raziskovalnem delu za pridobitev ustreznih podatkov za izračun vrednosti emisij. Rezultat naloge so izračunane vrednosti mase emisij ogljikovega dioksida na prevožen kilometer vozila, ki se gibljejo v primerljivem območju kot pri primerjalnem dizelskem vozilu. Splošna predpostavka, da so električna vozila popolnoma okolju prijazna iz vidika CO2 emisij, tako ni veljavna. This thesis reviews the carbon dioxide emissions of a specific electric vehicle that result from all phases of the vehicles lifespan (excluding recycling). The methodology used is based on research work to obtain relevant data for the subsequent calculation of emission values. The result of this work are calculated values of the mass of carbon dioxide emissions per driven kilometer of the electric vehicle. These values lie in a comparable range to those of a compared diesel vehicle. The general assumption that electric vehicles are completely environmentally friendly in terms of CO2 emissions is thus not valid.