Search the digital library catalog

Abstract: The main problem this research addresses is the EU energy policy, which focuses on a critical analysis of strategic energy management in all process phases. Particular emphasis is placed on strategic control, which is a key phase of the management process. Strategic control includes evaluating the effectiveness of implementing planned measures and making decisions about necessary adjustments or changes. The purpose of the study is to assess how well EU energy management strategies are aligned with policy objectives, in particular, to ensure energy security, sustainability and economic competitiveness, and at the same time to identify areas where improvements are needed to address current challenges. Energy management in the European Union is a crucial aspect of its energy policy, which focuses on ensuring energy security, sustainability and efficiency. Since the middle of the 20th century, organisations' increasing energy intensity has emphasized the need for a comprehensive and flexible approach. Energy management involves controlling the entire life cycle of energy - from extraction, conversion and distribution to consumption and waste disposal - in a complex environment shaped by various external factors. These challenges become even more pronounced in regions that experience frequent environmental, economic or geopolitical changes. Designing a universal model for global energy management is difficult because of the different conditions, regulations, and energy needs worldwide. Adaptable and adaptive strategies are essential to respond to supply and demand fluctuations, integrate renewable energy sources, manage geopolitical risks and achieve sustainability goals. Therefore, energy management must evolve to respond to a dynamic global environment. The EU prioritizes energy security but lacks a unified approach, which creates challenges in defining and measuring energy security. The absence of standardized criteria makes it difficult to strategically evaluate policies and make decisions, which could have long-term consequences for both energy and national security. Initially, energy security was focused on stable supply for economic growth, but global changes – such as rising demand, geopolitical tensions and environmental concerns – have made it more complex. The recent years have underscored significant vulnerabilities in global energy security and the sustainability of energy systems, particularly in Europe. The dual crises of the COVID-19 pandemic and the conflict in Ukraine have highlighted the urgency of addressing these challenges, pushing the European Union to accelerate its efforts toward more sustainable and secure energy practices. In response, the EU has diversified energy sources and strengthened energy security to reduce its dependence on politically unstable suppliers. Given the complexity of the geopolitical situation, disrupted supply chains and the EU's clear official commitment to decarbonisation by 2050, the above should be viewed from different angles. EU energy policy (short-term and long-term) is conditioned by the action of many factors, which differ in type, intensity of action and effect (positive or negative) - but the need to analyse existing and define new methodologies for evaluating the effectiveness of EU energy policy is evident. The doctoral dissertation examines the above and suggests improvements.
Keywords: Energy management, sustainable management, energy security, aggregate index, composite indicator
Published in DKUM: 10.04.2025; Views: 0; Downloads: 13
Full text (6,70 MB)

Abstract: The publication presents an overview of research activities and research achievements at the Faculty of Mechanical Engineering. The following research areas are presented: Energy, process and environmental engineering, Construction and design, Materials technology, Mechanics, Production engineering, Textile materials and design, and Fundamental and general areas. Individual laboratories and centers of the faculty present their research equipment, service offerings for industry, collaborations with companies and other institutions, the most prominent publications, patents, national and international projects and the most important research achievements.
Keywords: energy, construction and design, process and environmental engineering, materials technology, mechanics, production engineering, textile materials and design
Published in DKUM: 01.04.2025; Views: 0; Downloads: 2
Full text (18,43 MB)
This document has many files! More...

Abstract: Cavitation is the phenomenon of fluid evaporation in hydraulic systems, which occurs due to a pressure drop below the value of the vapor pressure. For numerical modelling of this generally undesirable phenomenon, which is often associated with material damage (erosion), there are various mathematical vapor transfer models that have been validated in the past. There are different approaches to predicting cavitation erosion, which have mostly been experimental in the past. Recently various numerical models have been developed with the development of numerical simulations. They describe the phenomenon of cavitation erosion based on different theoretical considerations, such as Pressure wave hypothesis, Microjet hypothesis, or a combination of both. In the present paper, an analysis of the Schnerr-Sauer transport cavitation model was used, upgraded with an erosive potential energy model based on pressure wave hypothesis for cavitation erosion prediction. The extended numerical model has been applied to the case of a radial divergent test section in three different mathematical formulations. The results of simulation were compared and validated to experimental work performed by other authors. The study shows that the distribution of surface accumulated energy agrees with the experimental results, although certain differences exist between formulations. The applied method appears to be appropriate for further use, and to be extended to materials response modelling in the future.
Keywords: kavitacija, erozija, erozivna potencialna energija, numerične simulacije, cavitation, erosion, erosive potential energy, numerical simulation
Published in DKUM: 26.03.2025; Views: 0; Downloads: 3
Link to full text
This document has many files! More...

Abstract: Optimal planting speed of vacuum maize planters is usually suggested by planter’s manufacturers, while increased planting speed may influence plant spacing and finally yield. Our hypothesis was that by increasing planting speed over the suggested level plant spacing variability will also increase which will result in decrease of silage and grain yield and saving of seed and energy. The field trial consisted of three planting speeds of 7, 9 and 11 km/h in the form of random blocks. The following measurements were taken as follows: plant spacing, silage and grain yield, fuel and energy use at planting. Results in this study show that planting speed did not have significant influence on silage and grain yield of maize, while up to 10% less seed was needed per hectare and fuel and energy use was lower for 15%. By the increase of planting speed the distance between the plants in a row, and in most cases also the plant spacing variability increased. It was noticed that by increasing planting speed plant density decreased. This research established that at higher planting speeds significant increase of the silage yield per individual plant and of the grain yield per individual plant was achieved. The ear parameters also show that the kernel mass per individual ear, the ear mass, and the cob mass, as well as the individual kernel mass, are larger at the planting speed of 11 km/h than at the planting speed of 7 km/h. At the latter planting speed, significantly higher fuel consumption per hectare and higher energy use was achieved than at the other two planting speeds. Overall the main benefits of planting speed of 11 km/h is saving seed and energy at planting while maintaning the same level of silage and grain yield compared to lower planting speeds used in the trial.
Keywords: energy use, grain yield, maize, planting speed, plant spacing, seed savings, silage yield, vacuum planter
Published in DKUM: 11.03.2025; Views: 0; Downloads: 4
Full text (386,40 KB)
This document has many files! More...

Abstract: Waste-to-energy (WtE) is a key part of modern waste management. In the European Union, approximately 500 WtE plants process more than 100 million tons of waste yearly, while globally, more than 2700 plants handle over 500 million tons. Roughly 20% of the waste processed is bottom ash (BA). However, this ash can contain heavy metals in concentrations that may render it hazardous. This paper presents a study focusing on stabilizing municipal solid waste incineration BA using simple and industrially viable treatments. The Slovenian WtE plant operator wishes to install the stabilization process; thus, the samples obtained from the plant were treated (1) with a CO2 gas flow, (2) with water spraying, and (3) with a combination of water spraying and a CO2 gas flow under laboratory conditions. Thermodynamic calculations were applied to define potential reactions during the treatment processes in the temperature range from 0 to 100 ◦C and to define the equilibrium composition of the treated ash with additions of CO2 and water. The standard leaching test EN 12457-4 of treated ash shows a reduction of over 40% in barium concentration and over 30% in lead concentration in leachates.
Keywords: heavy metals, waste-to-energy, bottom ash, leachate, reuse
Published in DKUM: 10.03.2025; Views: 0; Downloads: 6
Full text (2,72 MB)
This document has many files! More...