Статті КЕТтаОП (ДМетІ)

Permanent URI for this collection

http://crust.ust.edu.ua/handle/123456789/14989

ENG: Articles

Browse

Now showing 1 - 8 of 8

Determination of Operating Parameters of Accumulative Electric Heating Systems
(IOP Publishing Ltd, 2024) Kolienko, Anatoliy G.; Ahmednabiev, R. M.; Gupalo, Olena V.; Demchenko, O. V.; Hukasian, O. M.
ENG: The article presents the results of research aimed at determining the parameters and characteristics of storage heating systems, justifying the possibility of using heat accumulators to increase the efficient use of energy that is generated, including from renewable sources. The virtuality, frequency and significant dependence on natural conditions and climate of renewable energy sources, as well as the need to optimize their installed capacity, leads to the need to use energy storage installations. The presence of efficient energy batteries is a prerequisite for modern efficient energy and heat supply systems. The methodology of the work is based on our own theoretical and experimental studies, which provide practical recommendations for the arrangement of energy accumulators obtained using renewable heat sources. This is especially relevant for Ukraine during the period of active military operations on its territory, the destruction of traditional energy sources and a shortage of generating capacity. Recommendations have been developed for the design of heat accumulators for heating systems of residential and public buildings. Their effectiveness has been assessed under conditions of limited use of fossil fuels and the use of hybrid energy sources. Scientific and practical results of the work make it possible to carry out low-cost reconstruction of heating systems for the introduction of storage systems using electrical energy, the source of which is wind and solar energy. Such developments are becoming particularly relevant in Ukraine, taking into account the requirements for ensuring the stability and efficiency of infrastructure facilities in war conditions.
Improving the Technology of Using Freon-Steam Turbines in Mine Power Complexes
(IOP Publishing, 2022) Kirsanov, Mykhailo; Slobodiannykova, Inna; Gupalo, Olena V.
ENG: Mining power complexes can significantly reduce the cost of production of mining enterprises and increase their competitive position in the relevant market. To solve the urgent problem of further improving the operation of mine energy complexes, it is proposed to include in their composition installations for the useful use of energy from low-potential sources with a freon-steam turbine, which implement the thermodynamic Rankine cycle. The article considers the features of the organization of the Rankine cycle depending on the properties of freons. When choosing freons, the emphasis is placed on the use of strictly ozone-safe freons that meet modern requirements for normalizing the value of the global warming potential. The previously proposed method for calculating the thermodynamic parameters necessary for evaluating useful action’s coefficient of using specific freons in a useful energy recovery equipment has been improved. The calculation of the energy efficiency of the equipment with a freon-steam turbine for the selected options for the use of freons is performed. The analysis of the obtained results showed that the use of ozone-safe freons with low values of the global warming potential in installations for the utilization of energy from low-potential sources will improve the operation of mine energy complexes.
Method of Sequential Approximation in Modelling the Processes of Heat Transfer and Gas Dynamics in Combustion Equipment
(MDPI, Switzerland, 2022) Rimar, Miroslav; Yeromin, Oleksandr O.; Larionov, Grigoriy; Kulikov, Andrii; Fedak, Marcel; Krenicky, Tibor; Gupalo, Olena V.; Myanovskaya, Yana V.
ENG: The behavior of the processes taking place in furnaces determines the efficiency of fuel chemical energy utilization, the quality of the final products and the environmental safety of the production. Mathematical models of the processes of gas dynamics and heat transfer in the working space of heating equipment are quite complex, and do not allow the establishment of a direct analytical relationship between the quality indicator of the process (F) and the influencing parameters (xi). To simplify the procedure for obtaining the values of the function F depending on the change of parameters xi, a method of successive approximation is presented in the article. The main idea of the method is that the representation of the function around a point from the domain of the function can be extended to the entire domain for many problems of mechanics. The relative error in the definition of the function acquires its maximum value at the border of the area, and a reasonable narrowing of it allows control of the size of the error. Thus, the advantages of using the method are obvious; it is able to provide approximation of the function in a multiplicative form with a controlled error. The distribution of the method to the field of heat transfer problems is presented in this paper. The successful implementation of this method for solving problems of this kind shows that the solution of practical problems may be generalized for the entire domain of the function, despite the fact that the errors of such a representation increase to 5–7% when approaching its limit, which, however, may be considered acceptable for engineering calculations.
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.
Prediction of Fuel Consumption and Carbon Dioxide Emission when Replacing Gaseous Fuels with Renewable Hydrogen or Their Mixture
(IOP Publishing Ltd, 2024) Gupalo, Olena V.; Yeromin, Oleksandr O.; Kabakova, Liudmyla; Kolienko, Anatoliy; Kirsanov, Mykhailo; Kulikov, Andrii
ENG: The paper is devoted to predicting changes in fuel consumption and carbon dioxide emissions when industrial equipment is converted to heating with renewable hydrogen or a mixture of it with other gaseous fuels, such as natural gas. The authors developed a simplified methodology that is appropriate for assessing changes in the energy consumption of equipment and the environmental impact of fuel replacement at the stage preceding the equipment reconstruction. The peculiarity of the methodology is that it allows the calculation of fuel consumption and carbon dioxide emissions when fuel replacement is accompanied by the implementation of measures aimed at improving the energy efficiency of equipment. The methodology can be used for heating and thermal furnaces in metallurgy and mechanical engineering, units for heat treatment of raw materials in the mining and processing industries, heating devices in the food industry, and water and steam boilers. In the example of replacing natural gas with its mixture with renewable hydrogen of different compositions, it is shown that the calculation error using the proposed methodology in comparison with the results obtained by mathematical modeling of fuel combustion, gas flow and heat transfer in this furnace does not exceed 1.5%.
Rheological Properties of Polymer-Polymer Mixtures on Corn Starch Base
(MM Publishing s.r.o., Praha, Czechia, 2022) Rimar, Miroslav; Tretyakoff, Artem; Sukhyy, Kostyantyn M.; Yeromin, Oleksandr O.; Kulikov, Andrii; Fedak, Marcel; Belyanovskaya, Elena; Shunkin, Ihnat; Gupalo, Olena V.; Krenicky, Tibor
ENG: The prospects for the use of polymer-polymer mixtures based on corn starch as alternative thermoplastic materials to polyolefins are considered. Rheological curves have been obtained, which confirm the possibility of processing such mixtures on standard equipment into products. It is shown that the starch content in polymer-polymer mixtures can reach 90 mass percent. Compared to existing biodegradable polymers, plasticized starch-based material is in no way inferior to them in terms of processability. Studies of the mechanical properties of polymer-polymer mixtures based on corn starch have been carried out. The data obtained indicate the possibility of using the developed composites as packaging materials, as well as alternative materials to known bioplastics and synthetic polymers.
Study of the Efficiency of Using Renewable Hydrogen in Heating Equipment to Reduce Carbon Dioxide Emissions
(IOP Publishing, 2023) Gupalo, Olena V.; Yeromin, Oleksandr O.; Kabakova, Liudmyla; Kulikov, Andrii; Sukhyi, Mykhailo; Romanko, Yaroslav V.
ENG: The results of theoretical study of operation of continuous furnaces heated by natural gas, renewable hydrogen, and their mixture are presented. The furnaces have the same design, but significantly different energy efficiencies due to different heat losses and capability of recuperative fume gas heat utilization system. The measures to reduce heat losses and to increase air temperature for fuel combustion can reduce specific fuel consumption for metal heating and carbon dioxide emissions by 25.8% for natural gas furnaces. For furnaces operating on mixture of natural gas and hydrogen, a greater reduction in carbon dioxide emissions is achieved in furnaces with worse energy efficiency, but with greater fuel consumption for metal heating. The paper shows the possibility of converting a furnace with better energy efficiency indicators to be heated by mixture of natural gas (75%) and hydrogen (25%). The measure reduces the natural gas consumption and carbon dioxide emissions to 9.2% due to the use of hydrogen with specific consumption 13.81 m3 per ton of metal. To ensure the same costs for metal heating when transferring continuous furnaces from natural gas to hydrogen, or their mixture, the ratio of prices for natural gas and hydrogen should not exceed 0.301-0.312.
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.

Browse

Browsing Статті КЕТтаОП (ДМетІ) by Author "Gupalo, Olena V."

Results Per Page

Sort Options