Energy Efficiency of Tram Transport in the City of Osijek

In the city of Osijek, tram transport started long before it was introduced in many European and world cities. This paper presents the ways to increase tram traffic energy efficiency in the city of Osijek. The tram transportation system as an urban way of traffic as well as plans for further development are described. Energy efficiency indicators are presented based on electricity consumption and the number of passengers in the past decade. The tram transport system is compared with other forms of public transport in the city of Osijek. An increase in energy efficiency in the sector of urban transport is proved based on the presented data

Infrared thermography in steam trap inspection

Steam traps play a significant role in condensate evacuation from steam as well as in heating ventilation and cooling systems (HVAC), i.e., industrial climate chambers. Preventive maintenance and periodical audit of steam traps increase reliability and reduce the number of facility off hours. In some elements of the system, condensate can damage some parts, which means that monitoring their function is one of the basic preventive maintenance tasks. One way of checking steam traps is by using infrared thermography. The paper presents the simplicity of steam trap control by using an infrared thermography camera

Modelling Grounding Systems Using the Finite Element Method: The Influence of the Computational Domain Size on the Accuracy of the Numerical Calculation

Simulating the static and dynamic behaviour of grounding systems using numerical methods is a well-established procedure. In order to achieve greater model accuracy, a special attention is usually paid to the construction of more complex models. However, in the modelling process, there are certain factors that have a great influence on the model accuracy regardless of its complexity. They can drastically reduce the accuracy of high-quality complex models. The article elaborates on the ratio influence of the soil dimensions and the dimensions of the buried part of the grounding system, i.e. the influence of the edge distance of the hemispherical soil model from the centre of the grounding system (i.e. computational domain size) on the accuracy of the numerical calculation using the finite element method. In this paper, the physical cause of the influence of the computational domain size on the accuracy of the calculation is explained in detail. The paper gives a mathematical model that accurately describes the influence of the edge distance of the hemispherical soil model from the grounding conductors on the accuracy of the numerical calculation. Based on the presented theory, derived expressions and simulation results, guidelines in the implementation of numerical methods in modelling grounding systems are given. Also, the applicability of these guidelines in other applications such as modelling, analysis and interpretation of resistance data using FEM was considered

Essential Preventive Automobile Maintenance during a Pandemic

Passenger cars require different types of periodic maintenance. The most common and well-known procedure is the replacement of oil and filters, the so-called basic service. At the time of a pandemic, there is a need for social distance, reduced interaction between people and avoidance of all possible contamination of personal belongings. Oil and filter changes can be planned and optimized in advance but the replacement interval should not be exceeded for a long period of time. Regular replacement is essential to maintain reliability and operation lifetime of vehicles. Due to the unknown duration of the pandemic, the car owner can approach the maintenance procedure in a do it yourself (DIY) manner. Necessary spare parts can be ordered online and received by a delivery service without a human contact. The paper provides an overview of two-form practical implementation of basic maintenance that includes the replacement of lubricants and filters. The first maintenance form requires a skillful certified technician and the second form, as an interim service, can be carried out by an everyday user with a certain level of technical education who will independently and periodically monitor the car condition

Energy Efficiency of Tram Transport in the City of Osijek

In the city of Osijek, tram transport started long before it was introduced in many European and world cities. This paper presents the ways to increase tram traffic energy efficiency in the city of Osijek. The tram transportation system as an urban way of traffic as well as plans for further development are described. Energy efficiency indicators are presented based on electricity consumption and the number of passengers in the past decade. The tram transport system is compared with other forms of public transport in the city of Osijek. An increase in energy efficiency in the sector of urban transport is proved based on the presented data

Measures of the Winter Package EC and Biogas Power Plants in Croatia

This paper is based on the revised EU energy policy measures proposed by the European Commission in the so-called Winter Package, with special reference to biogas plants in the Republic of Croatia. The paper gives an overview of biogas power plants built in Croatia, a technological framework for their functioning, the installed power and their contribution to power supply in the country. The paper points to the importance of electricity and heat production from biogas power plants and the possibilities of a framework for the future development of these power plants in the Republic of Croatia

Recyclability and ecological-economic analysis of a simple photovoltaic panel

Photovoltaic industry has displayed an exponential expansion rate over the past two decades. Currently, 1185 GW of the global electricity demand is derived from photovoltaic (PV) panels with more to come in the next two decades. With the growing installment rate, a concern regarding managing panels that reached the end of their life-span grows. Despite the fact that the approximate life-span of a panel is 25 years, oftentimes this interval is shortened due to weather conditions, low-quality installations, and poor maintenance. Therefore, a global attention is focused on research and law-regulation of proper recycling and disposal of the PV waste. In this contribution, recyclability of one PV panel is determined upon subjecting it to the simplest recycling process, which is manual mechanical separation using common hand-tools. In addition, an ecological-economic analysis of the panel, which yields an absolute profit of the panel is presented

Analysis of Bearing Assemblies Refit in Agricultural PTO Shafts

The paper analyzes the problems of the most commonly used cardan shafts in agricultural machinery through a theoretical review and tests on a laboratory test bench. The aim of the research presented in this paper was to define the justification of a new method for retrofitting universal joint bearing units compared to the traditional methods of retrofitting. The new approach is based on energy efficiency (saving energy, raw materials and labor) compared to the conventional methods of retrofitting. The presented investigation to justify the proposed refit was carried out after the investigation of the extent of damage to the elements of the bearing assembly, which lasted 4.02 minutes per sample, with the aim of obtaining information essential for the purpose of our work. The proposed diagnosis and refit of the cardan bearings can help to extend the service life and improve the reliability of the universal joint shafts already in service. The results of the research have shown that the method with replaceable bushings (installation of undamaged surfaces in the load transfer zone) is 6.24 to 7.54 times cheaper than the complete repair of the elements of the bearing assembly, 2.11 to 2.83 times cheaper than the refit method, in which the damaged joints are replaced with new ones, and 1.62 to 2.74 times cheaper than the purchase of new double PTO (Power Take-Off) shafts

Infrared thermography in energy audit of electrical installations

Energetski pregled elektroenergetskih sustava sastavni je dio energetskog pregleda složenih tehničkih sustava, a infracrvena termografija jedna je od nezaobilaznih nedestruktivnih metoda ovakve vrste analize elektroenergetskih podsustava. Prilikom energetskog pregleda elektroenergetskog sustava termokamerom potrebno je provesti dodatna mjerenja električnih veličina što se često ne može izvesti na jednostavan način. Rad daje pregled standarda na području termovizije i kriterija ispravnosti elektroenergetskih instalacija na osnovu termograma uzimajući u obzir izmjerene električne veličine. Na praktičnom primjeru velikog složenog industrijskog potrošača prikazan je detaljan postupak analize i donošenja suda o ispravnosti instalacija kao i preporuka korektivnih radnji u postupku održavanja.Energy Audit of Electrical Installations is an integral part of the overall energy audit of complex technical systems, and infrared thermography is one of the non-destructive testing (NDT) methods for that type of analysis of power distribution subsystems. During the energy audit of the power subsystem by means of a thermal camera, it is necessary to carry out some additional measurements of electrical quantities which are often not performed easily. The paper provides an overview of the standards in the field of thermography and safety criteria of electrical installations based on a thermal image and measured electrical parameters. As a practical example, an analysis of an electric power distribution subsystem of large complex industrial consumers is presented.The procedure of the audit and decision making for future maintenance is described in detail. Recommendations of corrective actions in the maintenance procedure based on the absolute temperature criterion and the delta-T criterion under consideration of the measured load are given as well