Brodski sustavi ulja za podmazivanje

U radu su analizirani zahtjevi kojima ulja za brodske motore moraju udovoljiti. Posebna se pozornost posvetila, ne samo općenitim zahtjevima kojima trebaju udovoljiti sva industrijska ulja, već i specifičnim zahtjevima zbog korištenja ulja u uvjetima sagorijevanja teških ostatnih goriva s povećanim udjelom sumpora i vanadija. Dana je i ekonomska usporedba troškova plovidbe na destilatno i na ostatno gorivo. Razrađen je i osnovni princip rada sustava za podmazivanje, a priložena je i shema sustava za podmazivanje s opisom i određivanjem bitnih karakteristika pojedinih komponenti. Prikazana su brojna poboljšanja konstrukcije motora koja su potaknuta željom za usavršavanjem procesa izgaranja i potpomaganja sustava podmazivanja. Ukratko su prikazane i metode kontrole viskoznosti ulja

Energetska učinkovitost i ekološka prihvatljivost brodskih integriranih energetskih sustava

Suvremena rješenja u razvoju brodskih energetskih sustava (BES) zasnivaju se sve češće na integriranim energetskim sustavima (IES), čija je glavna značajka centralizirana proizvodnja ukupno potrebne količine električne energije korištenjem raznovrsnih pogonskih strojeva i uređaja, primjena elektromotornih propulzijskih sustava i visoki stupanj utilizacije otpadne toplinske energije. Sadašnje normativne metode za ocjenu energetske učinkovitosti i ekološke prihvatljivosti BES-a temelje se na Projektnom indeksu energetske učinkovitosti (eng. Energy Efficiency Design Index – EEDI) koji je definiran kao relativni omjer između ekvivalentne emisije CO2 i pripadajućeg gospodarskoga učina broda. Iskustvo u primjeni EEDI-a pokazuje da nije primjenjiv za IES-e. U sklopu ovoga doktorata analizirana je povezanost različitih parametara koji utječu na energetske i ekološke značajke različitih konfiguracija IES-a. Na temelju te analize definirana je metodologija pomoću koje se u brodograđevnoj praksi može valorizirati indeks energetske učinkovitosti i ekološke prihvatljivosti (eng. Index of Energy Efficiency and Environmental Eligibility – I4E) različitih konfiguracija BES-a (uključujući IES-e). Primjenom I4E na flotu ro-ro putničkih brodova pokazano je da je integralni utjecaj brodova s IES-ima na okoliš manji od brodova s konvencionalnim BES-ima

Determination of Actual Discharge of High-Pressure Low-Discharge Axial Piston Pumps

High-pressure low-discharge axial piston pumps are commonly used for the dosage of fluids of various physical properties and can be found in numerous technical systems. The discharge characteristics of these pumps should be very precise and reliable. Experiments performed with a high-pressure low-discharge axial piston pump show that in the operating range of the discharge pressure and stroke length, the actual discharge of the pump deviates from the theoretical one by up to35 %. The operation of non-return valves during the suction and discharge phases are analysed and the analytical expression that corrects this deviation is derived. The proposed expression predicts the measured discharge with a relative error of less than 3%

EEDI kao mjera energetske učinkovitosti broda

U cilju poticanja razvoja suvremenih tehnoloških rješenja koja doprinose poboljšavanju energetske učinkovitosti i unapređenju zaštite okoliša IMO Rezolucijom MEPC.203(62) donosi izmjene MARPOL-a, Prilog VI. Izmjene se odnose na obavezu uključivanja pravila za utvrđivanje i kontrolu energetske učinkovitosti u nacionalna pravila registara, kojima se propisuje obavezna primjena projektnog indeksa energetske učinkovitosti (EEDI) i brodskog plana upravljanja energetskom učinkovitosti (SEEMP). Dosadašnje iskustvo u primjeni formule za odreñivanje EEDI-a pokazuje da je potrebno prilagođavati vrijednosti i dopunjavati broj utjecajnih faktora ovisno o tipovima brodova i o njihovim specifičnim projektnim i eksploatacijskim značajkama. U radu su analizirani nedostaci primjene trenutno važeće (strukture) formule za odreñivanje EEDI-a. Za ro-pax brodove su posebno analizirani parametri za koje se smatra da značajnije utječu na vrijednost EEDI-a, a proizlaze iz različitih specifičnih projektnih i eksploatacijskih značajki tih brodova

The viability of short-sea shipping in Croatia

This paper analyzes the advantages of short-sea shipping (SSS) in Croatia as well as the environmental concerns related to shipping in general and short-sea shipping in particular. A comprehensive strengths-weaknesses-opportunities-threats (SWOT) study was undertaken with regard to the strategy of SSS development in Croatia. The study shows that strengths and opportunities largely diminish the significance of weaknesses and threats, provided that the emphasis in policy-making is placed on wider public, economic and environmental interests, as well as on the internalization of external costs. The impetus for conducting this study comes from new regulations within MARPOL Annex VI, oriented towards the reduction of GHG emission. They encourage the application of new technologies in existing ships as well as the development of new vessels that are able to fulfill new ecological demands. The a authors believe that with its long-lasting high-quality shipbuilding tradition and prestigious maritime education institutions, Croatia can respond to the need to protect its environment. A concept of a ship that meets these new criteria is proposed. The ship is intended for shuttling people and goods between local coastal communities in an environmentally friendly and socially and economically relevant way. The example demonstrates that what had at one time been considered as being remote future in SSS became a reality and a topic of great interest and importance

The challenges for Croatian fisheries within current regulatory environment

Biodiversity as a planetary boundary and sustainability are strongly related to fish stocks and fisheries that are regulated by a number of sources of law with the aim of achieving their sustainability. The paper analyses current application, impact and effectiveness of the Common Fisheries Policy that sets the rules for fishing fleets management in the European Union and for fish stocks conservation as well as the 2020 Report on its implementation by the European Court of Auditors. It also examines the present and potential implementation and effects of Blue Growth, Marine Strategy Framework Directive, United Nations legal framework and Sustainable Development Goals on fisheries and aquaculture activities in the Adriatic Sea, a semi-enclosed and biodiversity rich sea. Improvements in implementing marine ecosystem approach and marine spatial planning are proposed in policy and regulatory framework, focusing on characteristics of the Adriatic Sea. Resilient solutions require placing more focus on characteristics of regional seas and applying site-specific tailor-made solutions and less complex but efficient governance for the seas which entail integrated approach to exploitation and preservation of the resources and their health

Hibridni energetski sustav malog putničkog broda

Osnovni ciljevi razvoja modernih brodskih energetskih sustava su povećanje energetske učinkovitosti i pouzdanosti te ispunjavanje kriterija ekološke prihvatljivosti. Kriterij ekološke prihvatljivosti je posebno izražen kod putničkih brodova, trajekata, brodova za unutarnju plovidbu, itd. gdje problemi utjecaja na okoliš postaju sve važniji projektni kriterij. U članku je prikazan idejni projekt hibridnog energetskog sustava višenamjenskog putničkog broda, koji se sastoji od dizelskog motora, gorivnog članka i baterije kao izvora električne energije. Za tipične režime plovidbe odabranog broda određena je energetska bilanca. Uz analizu energetske učinkovitosti i ekološke prihvatljivosti, zaključno su istaknute prednosti i nedostaci predloženog rješenja u odnosu na klasične izvedbe brodskih energetskih sustava sa smjernicama za daljnja poboljšanja

A novel approach towards more realistic energy efficiency regulations for tankers

The Energy Efficiency Design Index (EEDI) regulation introduced by the Marine Environment Protection Committee (MEPC) within International Maritime Organization (IMO) has the aim to improve new vessel designs in order to reduce the shipping sector CO2 emissions. But the regulation, in its current form, does not effectively assess the ships energy performance. As the Attained EEDI calculation considers only a single operating point (75% main engine power, fully laden condition, calm seas, constant auxiliary engines power) and does not take into account the ship thermal power system, improvements of the ship energy efficiency cannot be assessed realistically. In this paper, a new approach is proposed to more realistically determine the energy efficiency for tankers. The proposed approach represents better the ship entire operating envelope whilst considering the major ship energy consumers. Thus, a better insight in the ship power system performance is provided allowing for the identification of operating points with low operational efficiency. If implemented for regulatory purposes, this approach could yield a higher impact on the tanker’s power plant design leading to the increase of the ship energy efficiency, the reduction of the GHG emissions and the ship environmental footprint improvement