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OPTIMIZACIJA VROČEVODNEGA OMREŽJA IN VPLIV VODNEGA KAMNA NA PRENOS TOPLOTE GRELNIH POVRŠIN
Danijela Urbancl, 2009, doktorska disertacija

Opis: Doktorska disertacija zajema tri sklope v katerih so predstavljene rešitve, ki lahko v znatni meri prispevajo k smotrni rabi energije, zmanjšanju škodljivih vplivov na okolje in posledično k ciljem, ki so prioriteta svetovne energetske in okoljske politike. Predstavljeni so statistični podatki o emisijah toplogrednih plinov in predlagani ukrepi za njihovo zmanjšanje. Raziskane so pretočno - tlačne zakonitosti sistema daljinskega ogrevanja ter z variacijo vplivnih parametrov v optimizacijskem modelu analiziran vpliv na potek optimalnih drevesnih poti v zankastem omrežju. Podrobneje je predstavljena morfologija vodnega kamna, katerega glavna sestavina je kalcijev karbonat v kalcitni ali aragonitni strukturi. V sklopu eksperimentalnega dela so izvedeni preizkusi izločanja vodnega kamna na grelcih bojlerjev za toplo vodo in na grelcih pralnih strojev. Analiziran je vpliv dvovalentnih ionov na kristalno obliko vodnega kamna in podana ocena zmanjšanega prenosa toplote zaradi oblog na grelcih iz različnih materialov. Predlagana je optimalna namestitev grelcev in oblika kadi, ki zagotavlja dobro turbulenco toka vode in manjšo tvorbo vodnega kamna.
Ključne besede: energetika, smotrna raba energije, prenos toplote, vročevodna omrežja, optimizacija, nelinearno programiranje, pralni stroji, grelci pralnih strojev, vodni kamen
Objavljeno: 06.05.2009; Ogledov: 3757; Prenosov: 280
.pdf Celotno besedilo (4,82 MB)

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Influence of water scale on thermal flow losses of domestic appliances
Danijela Urbancl, Darko Goričanec, 2007, izvirni znanstveni članek

Opis: Research results of how the precipitated water scale on heaters of small domestic appliances influences the consumption of electricity are presented. It shows that the majority of water scale samples are composed of aragonite, calcite and dolomite and that those components have an extraordinary low thermal conductivity. Also, the results show that at 2 mm thick deposit, depending on the chemical composition of water scale, the thermal flow is reduced for 10% to 40%; consequently, the consumption of electricity significantly increases.
Ključne besede: electricity, heat transfer, heat flow, heat exchanger, water scale
Objavljeno: 31.05.2012; Ogledov: 1147; Prenosov: 41
URL Povezava na celotno besedilo

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Optimisation of tree path pipe network with nonlinear optimisation method
Danijela Urbancl, Darko Goričanec, 2009, izvirni znanstveni članek

Opis: In this paper, the optimisation of pipe network with hot water is presented. The mathematical model, consisting of the nonlinear objective function and system of nonlinear equations for the hydraulics limitations is developed. On its basis, the computer program for determination optimal tree path with the use of simplex method was solved. For economic estimation the capitalised value method, which consider all costs of investment and operation was used. The results are presented for real case study network with 24 nodes and 33 pipe sectors.
Ključne besede: district heating, pipe network, optimisation, non-linear programming, simplex method
Objavljeno: 01.06.2012; Ogledov: 1228; Prenosov: 36
URL Povezava na celotno besedilo

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Influence of magnetic field on the aragonite precipitation
Lucija Črepinšek-Lipuš, Danijela Urbancl, 2007, izvirni znanstveni članek

Opis: Many laboratory investigations of magnetic water treatment (MWT) for scale control explained the formation of less compact scales by raised portion of aragonite, which is needle-like and less adhesive than rhombohedral calcite crystals, while our experiment was conducted with tap water, which contains Mg+2 and Fe+2 ions in concentrations exceeding thresholds for calcite inhibition, common for major tap waters. MWT efficiency was evaluated by amounts of scale precipitated in boilers and pipes during three-weeks run of two parallel experimental lines-one with and another without magnetic treatment. All scales were identified by X-ray diffractometer to be aragonite,but in the case of magnetic treatment, scales occurred in much smaller amounts: the scale on heating copper-pipe spiral was 2.5-times thinnerdue to MWT and in zinc-coated steel pipe occurred as very thin powder-like coating, while in the line without the treatment abundant hard lining was formed. The scalesć morphology was observed by scanning electron microscope: the husks from both lines consisted of parallel distributed needles, but these crystals were about four times thinner in the case of MWT. The present work demonstrates that hard scale deposits can form even under conditions where aragonite precipitates predominantly, and that MWT can also affect the crystallization of this polymorph in a manner conducive to scaling control.
Ključne besede: water, magnetic water treatment, scale, aragonite, cristallization, water supply pipes
Objavljeno: 01.06.2012; Ogledov: 1098; Prenosov: 33
URL Povezava na celotno besedilo

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TOPLOTNE IZGUBE ZARADI ODLAGANJA VODNEGA KAMNA NA GRELCIH GOSPODINJSKIH NAPRAV
Gregor Kravanja, 2012, diplomsko delo

Opis: V diplomskem delu je predstavljena učinkovitost magnetne obdelave vode (MOV) na zmanjšanje izločanja vodnega kamna. Preučevali smo vpliv različnih hitrosti pretoka vode skozi magnetno napravo za preprečitev nastajanja vodnega kamna na grelcih bojlerjev. Prav tako smo izvedli eksperimente z in brez Mg-elektrode pri različnih pretokih. Rezultati nakazujejo, da pri eksperimentih z Mg - elektrodo in napravo z MOV ni bistvenega učinka magnetne obdelave na zmanjšanje količine izločenega vodnega kamna. Pri eksperimentih brez Mg-elektrode in vključeno napravo za MOV pa se učinek magnetne naprave povečuje s povečanim pretokom vode. Predvidevamo, da se z dodatkom Mg - elektrode vpliv MOV izrazito zmanjša.
Ključne besede: vodni kamen, kalcijev karbonat, magnetna obdelava vode (MOV), Mg-elektroda, dinamičen fluidni sistem
Objavljeno: 20.09.2012; Ogledov: 1680; Prenosov: 225
.pdf Celotno besedilo (3,48 MB)

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