Browsing by Author "Podoliak, Kostiantyn"

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    New Working Fluids for the Use of Heat Secondary Sources in Mining Technologies
    (IOP Publishing, 2023) Kirsanov, Mykhailo; Gupalo, Olena V.; Podoliak, Kostiantyn
    ENG: Production cost of mining enterprises can be significantly reduced when using secondary heat. A large volume of secondary heat sources has a temperature potential of no higher than 50ºС. To generate additional electricity using secondary heat it has been proposed to use installations with the Rankine thermodynamic cycle in mining enterprises. The paper aim is to study the thermodynamic efficiency of using R-1234yf and R-744 in the equipment, which uses the secondary heat of mining technologies for evaporation of these working fluids. R-1234yf is a freon that belongs to the class of hydrofluoroolefins and has a much lower level of global warming potential than other ozone-depleting substances. R-744 is carbon dioxide, which belongs to a natural, non-toxic and non-flammable working substance. It has been determined that the thermodynamic efficiencies of using R-1234yf and R-744 are 10% and 6.3%, respectively. The thermodynamic efficiency has been calculated for the temperature range from 50º to 20ºC, which is typical for a large volume of secondary heat sources in mining technologies.
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    The Use of Secondary Heat Resources during the Accumulation of Compressed Air in Closed Mining Workings
    (IOP Publishing Ltd, 2024) Kirsanov, Mykhailo; Slobodiannykova, Inna; Gupalo, Olena V.; Podoliak, Kostiantyn
    ENG: The article considers the possibility of energy accumulation in mining workings in order to reduce the consumption of fossil organic fuel by the mining enterprise itself. For this purpose, the authors propose to accumulate compressed air in closed mine workings using secondary heat resources to generate additional electricity. The energy management of mining enterprises can be equipped with freon steam turbines which implement the Rankine thermodynamic cycle to obtain additional electricity from secondary heat. To measure the efficiency of the process, the air mast be compressed isothermally. The compression must be carried out in several stages, and the air must be cooled after each stage. Taking into account the development of energy storage technologies in the form of compressed air in specially prepared closed mining workings, the required air pressure can be from 70 to 90 at. The article assesses the possibility of using a secondary heat resource during air compression at mining enterprises. It is shown that the use of freon steam turbines during the accumulation of compressed air in underground pressure accumulators increases the subsequent production of electricity during the operation of the air turbine by 7.6% during the day.