Energija, ekonomija, ekologija最新文献

{"title":"Mogućnosti korišćenja otpadne drvne i poljoprivredne biomase u Srbiji u kogeneracionim postrojenjima","authors":"Srećko Ćurčić","doi":"10.46793/eee21-2.26c","DOIUrl":"https://doi.org/10.46793/eee21-2.26c","url":null,"abstract":"Wood and agricultural remains, such as raw materials can be used for heating (30% cheaper than gas from gas pipeline, 50% of electricity or heating oil), for electricity production and for other needs. In this paper, modern integrated solutions for the application of biomass and cogeneration will be presented. With such solutions, synthetic gas with certain content of methane is obtained in the gasification area, and then purified and used in a CHP (Combined Heat and Power) e.g., internal combustion engine. The gasification of waste wood and agricultural biomass for heat and / or electricity in the CHP plant preserves and saves optimally available resources. Gas obtained by gasification in the cogeneration plant is used in the gas engine that has an asynchronous generator for electricity production on its shaft. As for waste wood and agricultural biomass, they are very little used in energy in Serbia for energy purposes. The main reason for the non-use of waste and agricultural biomass for energy purposes in some production existences is due to the underdeveloped supply chains in the form of fuels that is suitable for use for energy purposes of these manufacturers. For the rational use of these resources, it is necessary to perform a study for defined energetic territories, which, among other things, should contain data for types and available quantities, formation of origin and energy potentials.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116041332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hibridni besprekidni sistem napajanja za navodnjavanje povrtarskih kultura na parceli “Grabovac”- Obrenovac","authors":"Željko V. Despotović, Ilija R. Stevanović","doi":"10.46793/eee21-2.17d","DOIUrl":"https://doi.org/10.46793/eee21-2.17d","url":null,"abstract":"The paper presents the realization of a hybrid uninterruptible power supply system used in drip and \"Agrokapilaris\" irrigation systems for vegetable crops on the experimental plot of the Secondary Technical Agricultural- Chemical School from Obrenovac, at the location of Grabovac. The hybrid power supply system is predominantly based on the use of renewable energy sources (wind and sun) with the use of a battery bank. An electronically controlled fast electronic static switch is additionally implemented, which ensures uninterrupted power supply to the irrigation system. The tendency is that the irrigation system primarily works in the so-called \"green energy use mode\", and only in cases of lack of wind and sun, or in case of battery discharge, the system automatically (in a very short time interval) switches to the 230 V, 50 Hz electricity distribution network. Within the realized system, a 500 W wind turbine, an 1100 W system of four photovoltaic panels, a 24 Vdc / 240 Ah battery bank and associated power electronics devices (MPPT battery chargers and 1600 W output power inverter) were installed.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116680139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Natural Gas Application in Combustion of Pulverized Solid Fuels – Reburning Technology","authors":"N. Hodžić, Kenan Kadić, A. Kazagić","doi":"10.46793/eee22-3.01h","DOIUrl":"https://doi.org/10.46793/eee22-3.01h","url":null,"abstract":"The energy transition basically implies a phased and significant reduction in the use of fossil fuels, until the final cessation of use in the near future. Renewable energy sources and alternative fuels are an increasingly important part of the energy transition. At the same time, it is necessary that energy systems increase energy efficiency and environmental acceptability. In this regard, great efforts are being made to expand the portfolio of primary fuels in existing large energy systems, e.g. thermal power plants. Therefore, today in large boilers, in order to reduce NOx emission, staged air supply for combustion is inevitably used as the primary measure in the furnace (air staging). In addition to the previous measure, there are many examples of staged fuel supply to the combustion zone (fuel staging), and still a small number of examples of the use of third or additional fuel, e.g. application of biogas or natural gas in combustion of pulverized solid fuels (reburning technology). General, these measures simultaneously increase the efficiency of primary energy conversion from fuel and reduce the emission of undesirable components into the environment. The results of this paper show the extent to which the effects of the use of natural gas in the co-firing of Bosnian coal and waste wood biomass are expressed. In this process there is an additional reduction of NOx in proportion to the share of gas - at a process temperature of 1350 °C and at 10% of the energy content of gas in combustion with coal, compared to emissions without additional fuel, recorded reduction of NOx emissions by more than 250 mg/mn 3.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"123 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134198501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Toplotno bilansiranje i povećanje efikasnosti korišćenja toplotne energije vrtića „Zeka“ u gradu Kragujevcu, Srbija","authors":"Davor Jovanović, Dušan Gordić, Jelena Nikolić, Nebojša Jurišević, Mladen Josijević","doi":"10.46793/eee20-1-2.119j","DOIUrl":"https://doi.org/10.46793/eee20-1-2.119j","url":null,"abstract":"This paper shows the thermal energy audit of the kindergarten \"Zeka\", located in the territory of the city of Kragujevac, Serbia. Data of the analyzed building, with an emphasis on the heating system, as well as the climate conditions of the location are shown. Analysis of the thermal energy use, done by implementing a software package \"URSA-građevinska fizika 2\", shows that the analyzed building belongs to the \"G\" energy efficiency level, which indicates that the heat transfer coefficients are not in the range defined by the Rule book of energy efficiency for buildings. Consequently, the energy conservation measures for increasing the efficiency of thermal energy use are proposed. Besides, for each measure, the techno- economic analysis was done, which includes determination of the investment costs, as well as the payback period. By implementing the appropriate measures in the analyzed building, it was concluded that thermal energy savings of almost 79% can be achieved.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133778458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rekonstrukcija transformatorske stanice 35/10kV u spoljašnje razvodno postrojenje 20kV 20211, XXIII","authors":"Srbislav Sarić, Biljana Sarić","doi":"10.46793/eee21-1.61s","DOIUrl":"https://doi.org/10.46793/eee21-1.61s","url":null,"abstract":"In the distribution area of Novi Sad, owned by ODS EPS Distribucija, there are 35 substations 35/10kV that are on average over 50 years old. Considering the tendency to gradually eliminate the voltage levels of 35kV and 10kV in this distribution area and the transition to the voltage level of 20kV, some of these substations are planned for reconstruction into 20kV distribution plants. Reconstruction of these substations requires large financial resources, because their construction part is in a very bad condition, electric power equipment is unreliable and difficult to maintain, and operational readiness is an increasingly important factor in presenting successful business. During the reconstruction of these transformer stations, the possibility of a backup power supply route for electricity customers, the speed of intervention and the smooth performance of preventive maintenance must be taken into account. The appearance of reclosers opened a new chapter in the world of electricity. Namely, now the above problems and requirements can be solved in a simpler and cheaper way with the use of reclosers. The paper will present a proposal for the reconstruction of the substaion 35/10 kV \"Kuzmin\" in the area of the Branch Distribution Sremska Mitrovica, which has been operating for more than 60 years, in an external 20 kV distribution plant formed with the help of reclosers built on steel lattice poles. The proposed solution can be used to solve the same or similar problems, primarily in the distribution area of Novi Sad.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"257 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132827182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kratkoročno predviđanje vibracionog ponašanja Fransis turbine nakon višedecenijske eksploatacije","authors":"J. Petrović, Ivana Božić","doi":"10.46793/eee21-1.32p","DOIUrl":"https://doi.org/10.46793/eee21-1.32p","url":null,"abstract":"Contemporary approaches in forecasting and preventing accidents, reducing the number and duration of downtimes, detecting and monitoring the failures in the real decades-long operating conditions of units in hydropower plants, are based on vibrodiagnostics. The multidisciplinary character of such approaches is reflected in the identification of certain vibrations in the hydro-aggregates, the application of various vibrodiagnostic methods, the quality assessment of measured data, as well as analysis and prediction based on artificial intelligence. The paper presents one of the possible approaches to solving the complex problem of predicting the behavior of a hydraulic turbine that has been in operation for more than half a century. An appropriate algorithm using artificial neural networks has been developed for short - term prediction of absolute and relative vibrations. The obtained results are presented depending on various operating conditions.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124816476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Particular Design Parameters of Radial Guide Vane Cascades on Their Hydraulic Performance at Variable Speed Operated Francis Turbines","authors":"F. Stojkovski, Z. Markov","doi":"10.46793/eee21-3.31s","DOIUrl":"https://doi.org/10.46793/eee21-3.31s","url":null,"abstract":"The design of radial blade cascades, with the intent to become turbine guide vanes, lies in the basis of satisfying turbine runner needs for a particular turbine design point of interest. For conventional turbine operation, the hydrodynamic parameters in the pre-runner space can be relatively easily estimated. For variable speed turbine operation at the constant head, these parameters change in a way that cannot be easily predicted using conventional techniques. In this paper, the guide vanes, as crucial turbine sub-system which needs to perform efficient runner flow feeding for these operating ranges, are numerically tested in various geometrical shapes and configurations, to observe the cascades behaviour, in a way of estimating which cascade configuration satisfies certain hydrodynamic and efficiency considerations of the operating points of interest. The criteria which the guide vanes need to meet are based on hydrodynamic parameters and expansion of the turbine operating range.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124336354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nestacionarno strujanje fluida u paralelnom cevovodu izrađenom od različitih materijala","authors":"M. Lazarevikj, V. Iliev, Valentino Stojkovski","doi":"10.46793/eee21-1.42l","DOIUrl":"https://doi.org/10.46793/eee21-1.42l","url":null,"abstract":"Transient fluid flow and the occurrence of water hammer in their specifics include the conditions of the environment in which the flow takes place. The variety of pipeline construction material (steel, polyethylene or other material) defines the conditions for the development of water hammer. The construction of parallel hydraulically connected pipelines from different materials and mutual influence in the conditions of transient fluid flow conditions of operation is the subject of research in this paper. The research was performed numerically on long (line) pipelines. The AFT-Impulse software package was used, which had already been tested with comparative experimentally measured values. The analysis model considers pipelines made of steel and polyethylene material in parallel hydraulic connection. The results of the simulation conditions are given through comparative diagrams, where the interactive influence is clearly and unambiguously revealed. The conditions of exploitation and interactive influence are given in the commentary and conclusion of this paper.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"33 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124465410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tehno-ekonomska analiza proizvodnje vodonika iz biodizela i njegove upotrebe za proizvodnju električne energije u gorivnim ćelijama za pogon električnih vozila","authors":"Iva Batić, Željko Đurišić, Miroljub Babić","doi":"10.46793/eee21-1.01b","DOIUrl":"https://doi.org/10.46793/eee21-1.01b","url":null,"abstract":"One of the possible directions of decarbonisation and electrification of freight and passenger transport is the use of fuel cells with hydrogen as a fuel. Considering that the use of biomass for electricity generation is largely uncompetitive compared to wind and solar power plants, its use for hydrogen production is one of the possible directions of development of this renewable energy source. In this paper, technologies for hydrogen production from biodiesel were analyzed. An analysis of the structure and total costs of hydrogen production from biodiesel was performed, as well as the energy balance of this process. The conditions of using hydrogen to drive fuel cells in electric vehicles were considered. The efficiency of the energy cycle analysis was performed: biodiesel - hydrogen - electricity - mechanical energy to drive electric vehicles. As a final result, an estimation of the costs of production of kWh of electricity from biodiesel and a comparative analysis with a vehicle powered by a diesel engine and an electric motor powered by batteries was performed.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115073159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Uloga i značaj Zajednica obnovljivih izvora energije u energetskoj tranziciji – neka zapažanja","authors":"G. Rimac","doi":"10.46793/eee21-4.64r","DOIUrl":"https://doi.org/10.46793/eee21-4.64r","url":null,"abstract":"Until recently, the prevailing idea was that for the functioning of the energy system it is necessary to be composed of large plants and for energy to move from the centre of production to cities and places of consumption. With the advent of decentralized energy production systems and new technologies for their use, the original model is changing more and more. EU Directive 2018/2001 on the promotion of the use of renewable energy sources (RES) designates “prosumers”, i.e. at the same time both producers and consumers of renewable energy, as well as RES communities, while EU Directive 2019/944 introduced the term “citizen energy communities”, i.e. civil energy communities, provided that this Directive, in addition to the distributive production of electricity from RES, also includes electricity from other sources. EU member states are obliged to adopt their own regulations regarding the implementation of the directives, and after that the appropriate incentive measures. The Energy Communities initiative offers citizens new opportunities in terms of active involvement in energy issues. As they are decentralized RES-based projects, they promote the practice of sustainable energy production and consumption, as well as energy storage and exchange within the community. Traditionally passive consumer becomes an energy “prosumer”, a co-owner of a RES plant and a member of the energy community. There are thousands of so-called RES cooperatives in Europe, which are the most common organizational form of energy communities and can play an important role in the process of decentralization of the energy system. The transition to decentralized energy production has many advantages, namely: the use of local energy sources, increased security of local energy supply, shorter transport distances and reduced losses in energy transmission, encouraging community development and creating local jobs. The purpose of this paper is to bring closer to the general public in Serbia the concept of energy communities, what they are and what their role is, with most of the work dealing with energy communities in the EU.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115682085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}