LIST OF ACCEPTED PAPERS

List of accepted abstract for the Symposium

• show abstract

  M. Babić, K.Darijević, D. Končalović, D. Jelić, D. Milovanović, D. Gordić, N. Jovičić, M. Despotović, V. Šušteršič - Mašinski fakultet, Univerziteta u Kragujevcu

  » PRIKAZ NOVE METODE ZA PRORAČUN I PROJEKTOVANJE MALIH VISOKOUČINSKIH HIDROELEKTRANA

  submitted by: MilunBabic
  Abstract text

  U okviru Katedre za energetiku i procesnu tehniku i Regionalnog evro centra za energetsku efikasnost Mašinskog fakulteta u Kragujevcu od početka osamdesetih godina prošlog veka realizuju se istraživanja vezana za korišćenje obnovljivih izvora energije, sa posebnim naglaskom na male hidroelektrane (MHE). Rezultati su brojni, a o uspešnosti istraživanja govore brojna domaća i međunarodna priznanja i tehničke izvedbe. Istraživanja su sledila tehničko-tehnološke mogućnosti istraživačke opreme, privrede i korisnika, i dovela su do toga da su do danas razvijeni softveri za direktan i inverzni proračun turbinskih delova MHE i izradu konstrukcijske dokumentacije.

  U želji da se javnosti saopšte mogućnosti nekih naših softvera, u ovom radu je ukratko opisan matematički model i procedura proračuna i projektovanja turbinskih delova MHE za unapred precizirane energetske mogućnosti konkretne lokacije na kojoj je planirana gradnja MHE. Kao argument za ocenu validnosti i potencijala naših istraživačkih rezultata izlaganja u radu je prikazana izgrađena MHE „Bosna 1“, snage 2x100 kW.
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  Vukman Bakić - Laboratory for Thermal Engineering and Energy, Institute of Nuclear Sciences Vinca, , PO.Box.522, 11000 Belgrade, Serbia , Goran Zivković - Laboratory for Thermal Engineering and Energy, Institute of Nuclear Sciences Vinca, PO.Box.522, 11000 Belgrade, Serbia , Milada Pezo - Laboratory for Thermal Engineering and Energy, Institute of Nuclear Sciences Vinca, , PO.Box.522, 11000 Belgrade, Serbia , Branislav Stanković - Laboratory for Thermal Engineering and Energy, Institute of Nuclear Sciences Vinca, , PO.Box.522, 11000 Belgrade, Serbia , Valentina Turanjanin - Laboratory for Thermal Engineering and Energy, Institute of Nuclear Sciences Vinca, , PO.Box.522, 11000 Belgrade, Serbia

  » INFLUENCE OF THE WIND ON THE WORKING PARAMETERS OF THE FLAT PLATE COLLECTORS

  submitted by: VukmanBakic
  Abstract text

  This paper deals with the numerical simulation of air flow (induced by the wind) around the arrays of flat plate collectors and determination of the flow field, which should provide a basis for convective heat losses, as a parameter which influences their working characteristics. The heat losses are the result of the reflection on the glass, conductive losses at the collector’s absorber plate, radiation of the absorber plate and convective losses on the glass. Wind velocity in the vicinity of the absorber plate depends on its position in the arrays of collectors. The results of the numerical simulation of flow around collectors are boundary conditions, and they are used for modeling thermal-hydraulic processes inside the solar collector. In this paper method for coupling thermal-hydraulic processes inside the collector with analyses of the heat transfer from plate to tube bundle is developed for determinate distribution of the temperature of the absorber plate and the efficiency of the flat plate collectors. Analyses of flow around arrays of collectors are preformed with RNG k - ε model. Free-stream velocity is 1 m/s, 5 m/s and 10 m/s and angle of attack is 20o and 40o. Heat transfer coefficient is determined from the theory of boundary layer. Heat transfer inside the plate cavity is analized for constant intensity of radiation.
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  Willem van der Westhuizen - Pump Consultant, Eskom Enterprises Engineering, Johannesburg, South-Africa

  » SELECTING THE OPTIMISED PUMP CONFIGURATION AND DRIVE OPTION FOR THE CONDENSATE EXTRACTION AND BOILER FEED PUMPS FOR THE NEW ESKOM SUPERCRITICAL POWER STATIONS

  submitted by: Willem
  Abstract text

  The increasing growth in the Economy and increase in the Power Demand in South Africa, Eskom has embarked on a huge Capital Expenditure to increase the power development. The new power development undertaken for the future includes: Fossil, Nuclear, Pebble Bed Modular Reactor, Hydro, Open Gas Cycle, Combined Cycle, Wind and Solar Energy.

  The first two new Supercritical Fossil fired Power Stations Medupi (6 Units, each 650 MW) and Kusile (6 Units, each 800 MW) are presently in the design and construction phase.

  The condensate extraction pumps and boiler feed pumps are two of the highest auxiliary power consumers within a power station. It is therefore of utmost importance to select the correct optimised pump configuration and drive option for both these pumps.

  The paper describes how the final selection for the two new Supercritical Power Stations, Condensate Extraction Pumps was made. The option of a vertical versus a horizontally positioned pump, based on an Air Cooled Condenser was considered. Both Condensate Extraction Pumps are each sized for 100% bypass operation. The paper discusses why two 100% duty pumps were selected with one being variable speed electrical driven and the standby one fixed speed electrical driven.

  The two new Supercritical Power Stations also opted for a 3 x 50% boiler feed pump configuration to be installed to achieve the high required plant availability.

  The paper also discusses four different variable speed boiler feed pump drive options that were available for selection.

  The details of each variable speed drive option are included and discussed. The final decision in selecting the optimsed Boiler Feed Pump drive was based on an economic evaluation model that included three different modes of operation, i.e. (Base Load, Load Following and Two Shifting), initial capital cost and Auxiliary Power Consumption – (Boiler feed pump set efficiency) over the 50 year life time of the power station.

  (Eskom is the South-African Power utility and is the fifth largest electricity utility in the world and supplies 99% of South-Africa’s power and 55% of the power generated on the African Continent)
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  Dr Dušan Arnautović, Zoran Ćirić, Dr Đorđe Stojić, Mr Ilija Stevanović - Institut "Nikola Tesla", Beograd

  » MODERNIZACIJA, REKONSTRUKCIJA I RAZVOJ STATIČKIH SISTEMA POBUDE GENERATORA

  submitted by: DusanArnautovic
  Abstract text

  U radu se izlažu rezultati istraživanja i rada na razvoju, izradi i puštanju u rad statičkih sistema pobude sa digitalnim automatskim regulatorom napona, urađenih po najsavremenijoj mikroprocesorskoj tehnologiji. Time se omogućuje smanjenje investicionih ulaganja prilikom kapitalnog remonta TE ili HE, revitalizacija, rekonstrukcija ili zamena postojećih i ugradnja novih statičkih sistema pobude u TE ili HE, sa jedne strane, kao i poboljšanje tehničkih karakteristika i omogućavanje uključenja sistema pobude u digitalni sistem za nadzor i upravljanje elektranom. Takođe, omogućuje se povećanje raspoloživosti, stabilnosti i kvaliteta električne energije i sposobnoasti povezivanja EES Srbije u interkonekcije, kao i povećanje pouzdanosti rada generatora, a time i celog EES.

  Konkretno, u periodu 2005.-2007. godine u Elektroprivredi Srbije izvršena je rekonstrukcija ili zamena šest statičkih sistema pobude sa digitalnim automatskim regulatorom pobude. U TE „Nikola Tesla A“ na generatorima A5 i A4 snage 365 MVA i generatoru A2 snage 210MW. U TE-TO „Novi Sad“ na generatoru A2. U HE „Kokin Brod“ na generatorima A i B snage 12.5 MVA.
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  M. Zlatanović - Elektrotehnički fakuletet Univerziteta u Beogradu, J. Vujić - Delta 90, 11000 Beograd, Požeška 80/21

  » ECO HOUSE FOR DEMONSTRATION OF RENEVABLE ENERGY SOURCES APPLICATION

  submitted by: bata
  Abstract text

  The old forestry service house Rošijana, located in Special Nature Reserve (SNR) Deliblatska Peščara (DP) was selected for the case study of renewable energy sources (RES) application. The main objectives were to suggest the optimal design of RES installation, the assessment of economic benefits, life cycle analysis of proposed installations and comparison with the other methods of electricity supply. It was also found that the region has plenty of RES and other energy sources: geothermal energy, sun radiation, biomass, hydropower, natural gas and coal. The wind was considered as the main renewable energy source and decision was made to supply the electricity originating from wind energy conversion to Rošijana eco-house. The assessment of wind potential at selected location was found of crucial importance for the case study realization. All the analyses related to optimization of wind conversion installation, economy consideration, environmental, social and other aspects of wind conversion to electricity are based on wind potential data. The contacts were made with the people living in Šušara village close to Rošijana site, with the local municipalities, public company responsible for SNR protection and development, with nature protection organizations, non-profit and non-government organization, with small farm houses, small and medium enterprises (SMEs) and large companies interested in RES application, institutions for planning and nature protection, government organizations and many individuals with the knowledge of local history, economy, life protection and upgrading all aspects of regional life. From the site visits it was learned that over one-century experience exists in using and controlling wind energy in the region close to Rošijana site. One century ago the wind turbine was used for water supply of Šušara village 3 km far from Rošijana and many actions to suppress the aeolian erosion of sandy region of Deliblatska Peščara were taken. In small town Uljma about 17 km far from Vršac there is a small enterprise for wind turbine blades and other turbine parts production. Orography, roughness and shelters data were collected together with data on Special Nature Reserve rules, as well as urban conditions and other policies related to design and activity of future eco-house Rošijana. In the case study preparation the wind databases contained in some software packages, data collected at surrounding met stations, as well as data collected at Zagajičko brdo specialized wind mast station were used. Database from Zagajičko brdo 50m tall wind measuring tower obtained during two years campaign was only found relevant for more precise case study. The optimization criteria of RES installation were considered from technical, economy, environmental and social aspects. Maximum annual electricity production was calculated for the selected wind turbine. It was concluded that Rošijana eco-house considering RES application meets all the requirements from energetic, environmental, social and educational point of view.
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  Slobodan Stupar - Mašinski fakultet, Beograd, Dragan Komarov - Mašinski fakultet, Beograd, Aleksandar Simonović - Mašinski fakultet, Beograd, Branislav Stefanović - TE Kolubara, Veliki Crljeni

  » Uticaj vrste ispune na radne karakteristike rashladnih kula br.16 i 18 TE Kolubara A/Fill influence on Performance Parameters of Cooling Towers no. 16 and 18 in TE KOLUBARA A

  submitted by: sstupar
  Abstract text

  Rezime

  U radu je izvršeno poređenje stare drvene i nove PVC ispune ugrađene pri rekonstrukciji druge faze rashladnih tornjeva broj 16 i 18 trećeg bloka TE Kolubara A. Blok tri rashladne kule (16, 17 i 18) je gašenjem RK br. 17, zamenjen sa dve kule.

  Pored adekvatnih termodinamičkih karakteristika izabrana ispuna je morala zadovoljiti kriterijume vezane za samoispiranje zbog lošeg kvaliteta rashladne vode i opasnosti od zagušenja. Perforacija ispune i veličina kanala je takva da obezbeđuje dobre termodinamičke i strujne karakteristike uz samoispiranje.

  Projektom rekonstrukcije rashladni kapacitet dve rashladne kule je povećan tako da zamenjuje dosadašnje rešenje sa tri rashladne kule u bloku. Protok vode kroz rashladnu kulu je povećan za 50%. Iako je hidrauličko opterećenje rashladne kule povećano, strujne karakteristike ispune su takve da je pad pritiska koji ventilator treba da savlada smanjen. S obzirom da se ukupan protok vode u sistemu nije promenio hidraulične pumpe rade u istom režimu kao i ranije. Gašenjem srednje kule i ugradnjom pomenute ispune u preostale dve kule bloka ostvaren je potreban rashladni kapacitet uz uštedu u energiji i održavanju.

  Abstract

  Comparison of old wooden and reconstruction replacement PVC fill of second phase cooling towers no. 16 and 18 in the third thermoblock of Thermopower plant Kolubara A have been done in this paper. Group of three cooling towers (16, 17 and 18) is replaced with two by shuting down of cooling tower number 17.

  Beside adequate thermodynamic properties, chosen fill had to meet antifouling criteriums due poor water quality and danger of flow obstruction. Fill perforation and chanel size provide good thermodynamic, flow and antifouling characteristics.

  Cooling capacity of two cooling towers have been increased in order to replace former block of three cooling towers. Water flow through cooling tower is increased by 50%. Despite increase of hydraulic load, due to fill flow characteristics pressure drop that fan have to overcome is reduced. Unchanged water flow through system provided hydraulic pumps to remain in the same regime as before. Required cooling capacity is obtained together with energy and maintenance savings by turning off of the middle cooling tower and using mentioned fill in remaining two towers of the block.
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  M. Benišek - Faculty of Mechanical Engineering University of Belgrade, D. Petrović - Faculty of Electrical Engineering University of Belgrade , I. Božić - Faculty of Mechanical Engineering University, Z. Ćirić - Electrical Engineering Institute “Nikola Tesla”– Belgrade, S. Damjanović - HPS Zvornik – Mali Zvornik, M. Zeljić - HPS Zvornik – Mali Zvornik

  » PROPELLER AND COMBINATORY CHARACTERISTICS DETERMINATION OF KAPLAN TURBINE IN HPS ZVORNIK WITH THE AIM OF INCREASING ITS EFFICIENCY

  submitted by: MiroslavBenisek
  Abstract text

  "ODREĐIVANJE PROPELERNIH I KOMBINATORSKIH KARAKTERISTIKA KAPLANOVE TURBINE AGREGATA U HE ZVORNIK U CILJU POVEĆANJA NJEGOVE EFIKASNOSTI"

  The measurement and calculation results which were performed at unit A3 in HPS Zvornik are presented in this paper with the aim of Kaplan turbine propeller and combinatory characteristics determination. Special attention is given to the Winter-Kennedy discharge coefficient determination and to comparison between values obtained by direct method and Index test. These measurement procedures gave the opportunity for unit operation at optimal efficiencies.
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  S. R. Marinković, P.D. Trifunović, A. B. Kostić-Pulek, R. D. Tokalić - Rudarsko-geološki fakultet Univerziteta u Beogradu

  » INVESTIGATION ON THE POSSIBILITIES OF THE APPLICATION OF FLY ASH AND BOTTOM ASH FROM „NICOLA TESLA“ POWER PLANTS - OBRENOVAC FOR ROAD CONSTRUCTION

  submitted by: tokalic
  Abstract text

  "ISPITIVANJE MOGUĆNOSTI PRIMENE PEPELA I ŠLJAKE TERMOELEKTRANA „NIKOLA TESLA“ - OBRENOVAC ZA IZGRADNJU PUTEVA"

  Fly and bottom ash are waste of thermal power plants. The „Nikola Tesla“ power plants (TENT) - Obrenovac are the biggest producer of them in Serbia. Fly ash from TENT is cha¬racte¬rized as „dangerous industrial waste”. Disposal of coal ashes produces ecological and economic problems. Consequently, it is always preferable to utilize than dispose of them (recycling of waste). Coal ashes can be utilized in bulk only in road construction. In this sense, the application of fly and bottom ash as a component of base and sub-base mixtures for road construction is of great interest.

  This paper is part of investigations of the Project “Investigation of possibilities of application of fly and bottom ash, waste from power plants, in construction”, supported by the Serbian Ministry of Science and the TENT-Obrenovac.

  The obtained results are on laboratory level and their confirmation in practice could be very important for Serbia and TENT.
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  Borislav Jeftenić - Elektrotehnički fakultet, Univerzitet u Beogradu, Leposava Ristić - Elektrotehnički fakultet, Univerzitet u Beogradu, Milan Bebić - Elektrotehnički fakultet, Univerzitet u Beogradu, Saša Štatkić - Fakultet tehničkih nauka, Kosovska Mitrovica, Dragan Jevtić - Elektrotehnički fakultet, Univerzitet u Beogradu, Neša Rašić - Elektrotehnički fakultet, Univerzitet u Beogradu

  » PRIMENA SAVREMENIH REGULISANIH POGONA NA RUDARSKOJ MEHANIZACIJI

  submitted by: leposava
  Abstract text

  Energetska efikasnost je danas ključni element u energetskoj politici svih razvijenih zemalja sveta, jer se njome unapređuje efikasnost ekonomije, povećava se sigurnost u napajanju energijom, produžava vek korišćenja neobnovljivih izvora energije, pre svega iz fosilnih goriva, iz kojih se danas dobija najveći deo električne energije. Smanjenje potrošnje energije, posebno one koja se dobija iz fosilnog goriva, kroz unapređenje energetske efikasnosti je jedan od glavnih instrumenata za ispunjavane obaveza u sferi ekologije. Osnovni problem kod mehanizacije na našim površinskim kopovima je njihova velika starost, što za posledicu ima smanjenu produktivnost i povećane troškove eksploatacije i održavanja, tako da je neophodno izvršiti njihovu revitalizaciju i modernizaciju kako bi im se produžio životni vek, ali i poboljšale tehničke performanse (veći kapacitet, manja potrošnja energije, bolja i efikasnija zaštita i dr.).

  Danas je sve veći trend u svetu da se pogoni na rudarskoj mehanizaciji ostvaruju sa kaveznim asinhronim motorima koji se napajaju iz frekventnih pretvarača. U radu će biti dat detaljan pregled primene savremenih regulisanih pogona kod:

  − pogona radnog točka rotornih bagera,

  − pogona okreta gornje gradnje bagera i odlagača,

  − pogona guseničnog transporta bagera i odlagača,

  sa rezultatima merenja na realizovanim pogonima.

  Kod pogona radnog točka rotornih bagera u cilju zaštite radnog mehanizma, kofica, zuba, spojnica i reduktora, potrebno je raspolagati efikasnim sistemom ograničenja (limitiranja) momenta motora. Naime, u slučaju preopterećenja usled prevelikog nastupa, brzine kretanja, ili nailaska na tvrd materijal, pogon mora da uspori, ili se isključi dovoljno brzo da ne bi došlo do neželjenih oštećenja. Savremeni elektromotorni pogoni sa frekventnim pretvaračima raspolažu ovim mogućnostima, t.j. kod preopterećenja oni smanjuju brzinu na potrebnu vrednost, a po prestanku preopterećenja automatski ubrzavaju do zadate brzine bez zaustavljanja, i nepotrebnog prekida procesa otkopavanja.

  Upravljačke karakteristike pogona okreta su vrlo zahtevne, zbog potrebe za čestim promenama smera i ostvarivanjem složenih upravljačkih algoritama. Poseban problem predstavlja činjenica da zbog čestih promena smera, kočenja i ubrzanja, mehanički sklopovi pogona, reduktori, pogonski zupčanici i zupčasti venac, rade u ekstremno teškim uslovima. Takođe, ovaj pogon je višemotorni, tako da se koordinaciji rada između pojedinih motora mora posvetiti posebna pažnja, pre svega raspodeli opterećenja. Zbog navedenih činjenica ovaj pogon je uvek realizovan kao regulisani pogon.

  Pogon guseničnog transporta rudarskih mašina je višemotorni pogon, koga čine dva, četiri, šest ili više motora. Ovaj pogon je najzahtevniji pogon na mašinama na kopovima. Pojedini pogoni su međusobno spregnuti u jednu kvazi krutu mehaničku spregu, preko podloge koja je neravna i nehomogena. Zbog ovoga se odnos sprezanja pogona u toku kretanja stalno menja, na unapred nepredvidiv način. Kod vožnje kroz krivinu potrebno je obezbediti kretanja pogona bitno različitim brzinama. Poseban problem je i činjenica da se veza sa tlom ostvaruje preko gusenica, koje u sistemu prenosa stvaraju značajne zazore. Zahtev za ravnomernom raspodelom opterećenja između pojedinih motora ostvaruje se upravljačkim sistemom, a pogoni se danas realizuju sa kaveznim asinhronim motorima napajanim iz frekventnih pretvarača.

  Ostvareni rezultati na realizovanim pogonima, dobre eksploatacione karakteristike, smanjene potrebe za održavanjem, kao i povećana energetska efikasnost, ukazuju na prednosti primene regulisanih pogona sa kaveznim asinhronim motorima napajanim iz frekventnih pretvarača na rudarskoj mehanizaciji.
• show abstract

  R. V. Filkoski, I. J. Petrovski, B. S. Avramovska - University „Sts Cyril and Metodius”, Faculty of Mechanical Engineering

  » ENERGY TRANSFORMATIONS AND GHG EMISSION MITIGATION OPTIONS IN MACEDONIA

  submitted by: Filkoski
  Abstract text

  Abstract: The energy transformations are by far the largest source of greenhouse gases (GHG) emission in the Republic of Macedonia. The paper is a result of an analysis of GHG emission by sectors, consisting of GHG emission inventory, mitigation analysis and action plan. The analysis was provided in the framework of the preparation of the Second National Communication towards the UN Framework Convention on Climate Change. Some possibilities and options have been envisaged for reduction of emission of CO2 and other gases that cause the greenhouse effect, and that originate from the energy transformations in the power generation, industry, residential, public, commercial, agricultural and other sectors. Considering the overall actual situation in the energy sector, as well as the limited domestic energy resources, the general conclusion is that, the possibilities for significant reduction of CO2 emission in this segment, in middle term, are not huge, but they are not insignificant. On the other hand, there are very good opportunities for proposing qualitative projects in the framework of the Kyoto Protocol Clean Development Mechanism (CDM).