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Постійне посилання колекціїhttps://dspace.nuft.edu.ua/handle/123456789/7522
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Документ Optimization strategy for system management of cold thermal energy storage (CTES) in conditions of dynamic changes in energy carrier value(2024) Gryshchenko, Roman; Forsyuk, Andriy; Ivashchenko, Nataliia; Kryvosheiev, Maksym; Pylypenko, OleksiiIn the world of contemporary challenges involving the continual increase in demand for energy resources and corresponding environmental pollution, the necessity has arisen to develop and implement advanced technologies to reduce energy consumption. This calls for enhancing energy utilization efficiency and op-timizing energy generation systems, taking into account the utilization of alternative and renewable ener-gy sources.Specifically, thermal energy storage becomes crucial as an effective economic option. Ther-mal energy storage systems enable meeting heating or cooling needs during optimal periods when it is more energy-efficient. Traditional management methods rarely prove optimal due to fluctuating electrici-ty tariffs, cooling loads, and ambient temperature. This leads to suboptimal achievement of maximum savings in utilising thermal energy storage systems.In this work, the advantages of Cold Thermal Energy Storage (CTES) systems based on Ice Thermal Energy Storage (ITES) were analysed alongside existing management strategies implemented in most enterprises and buildings utilizing ITES. A simpli-fied engineering methodology for analysing the thermodynamic efficiency of CTES was proposed. It was determined that cold losses during exergy analysis during storage are caused by both losses through sur-faces and internal exergy losses (i.e., exergy consumption due to irreversibility within the reservoir). For modern systems, exergy losses encompass both external and internal components. As an example, if the heat transfer at the external surface temperature of the storage reservoir equals the ambient temperature, external exergy losses would be zero, while total exergy losses would be entirely due to internal consump-tion. Conversely, if heat transfer occurs at the liquid's temperature for storage, a greater portion of exer-gy losses will be due to external losses. In all cases, the cumulative exergy losses, comprising internal and external exergy losses, remain constant.The implementation of CTES allows for shifting the use of electrical energy from peak to off-peak hours. During off-peak hours, electrical energy is used to charge the storage to fulfil (fully or partially) the peak demand for refrigeration equipment. Ice-based ITES has the potential to reduce maximum energy consumption, peak demand, and most importantly, the average cost of energy consumed.Документ Energy-saving rectification technology with controlled mass exchange cycles between liquid and vapor(2021) Buliy, Yuri; Kuts, Anatoly; Forsyuk, Andriy; Chumachenko, SergiiPurpose of the article: the definition of the hydrodynamic mode of operation of barbotage perforated plates, of the efficiency of the technology of cyclic rectification in the mass-exchange columns equipped with barbotage perforated plates with variable free cross-sectionin and determining the consumption of heating steam in the rectificational and epyuratin columns. Research methods - analytical, chemical, physico-chemical with the use of instruments and research methods used in the production of rectified ethyl alcohol. Fluid consumption was controlled with the help of flowmeter RM, air velocity in the free section of the column - anemometer MS-13, in the holes of the plates - by calculation method. The concentration of volatile impurities of alcohol was determined on a gas chromatograph with a column HP FFAP 50 m × 0.32 m. Analysis of research samples was performed according to the State Standard of Ukraine 4222:2003 "Vodka, ethyl alcohol and water-alcohol solutions. Gas chromatographic method for determination of microcomponents content". An energy-saving technology of cyclic rectification with a continuous supply of heating steam and liquid to a mass-exchange column apparatus equipped with flake plates is proposed. The innovative method allows to prolong the time of contact of steam and liquid on plates up to 40-60 s and to reduce the time of overflow up to 1-1,7 s. In order to implement the technology, a rectification column design was proposed, equipped with flake plates with variable free cross-section.Документ Improving the efficiency of mass-exchange between liquid and steam in rectification columns of cyclic action(2021) Buliy, Yuri; Kuts, Anatoly; Yuryk, Ivan; Forsyuk, AndriyThe purpose of the work was to determine the optimal time of residence of the liquid on the plates, the grade of extraction and concentration ratio of volatile impurities of alcohol and the specific consumption of heating steam in rectification columns of cyclic action. The studies were carried out in a rectification column, equipped with flaky plates with a variable free cross-section. Concentration of alcohol volatile impurities was determined by chromatographic method, the grade of their extraction and concentration ratio – by calculation method, other indicators – by commonly known methods. The maximum extraction of volatile impurities was being achieved in a rectification column, equipped with flaky plates containing turnaround sections connected to drive mechanisms, the action of which is occurred according to a given algorithm. The optimal parameters of operating the column were: vapor velocity in the orifices of the flakes during the period of liquid retention on the plates 12-14 m/s; during liquid pouring 1-1.5 m/s; time of residence of the liquid on the plates 40 s, pouring time 1.7 s; pressure in the lower part of the column 12 kPa; the concentration of ethyl alcohol in the still liquid 3-4% vol. In order to provide the cycles, the free sectional area of the plates must change instantaneously from 5.5 to 51.7%. This technical solution allows to provide complete disposal of ethers, methyl acetate and isopropyl alcohol, to increase the grade of extraction of higher alcohols of sivush oil and methanol by 38%, the concentration ratio of aldehydes by 25%, higher alcohols by 38%, methanol by 37%, and to reduce specific consumption of heating steam by 40% compared to a typical column operating in stationary mode.Документ A study of water ice formation and melting processes on vertical cooled pipes(2016) Zasiadko, Yaroslav; Pylypenko, Oleksii; Forsyuk, Andriy; Gryshchenko, RomanThe use of cold accumulators based on the principle of water ice formation on the cooled surfaces during off-peak periods and water ice melting during on-peak periods is an effective method of electricity bills reduction. Within comparatively short periods of on-peak demand a noticeable amount of thermal energy related to ice melting is to be released, it becomes clear that not only sizing of ice accumulators based on balance calculations is actual, but also the determination of time periods of ice accumulation becomes critical. This work presents an experimental unit for obtaining data on the ice formation on the vertical cooled pipes and later on to continuously register data on the ice thickness diminishing at the regimes of ice melting when cooling of pipe stops. The data for ice formation and melting for some regimes have been presented and analyzed. The data form the base for deriving semi-empirical correlations allowing to determine time intervals necessary to generate of water ice layers of given thickness.Документ 3-D modeling of water flow and cooling down within the temperature range close to inversion point(2016) Gryshchenko, Roman; Zasiadko, Yaroslav; Forsyuk, Andriy; Pylypenko, OleksiiThe research and simulation of heat transfer during water refrigeration in the experimental section close to the vertical pipe which is cooled down considering abnormal character of water density change from the temperature in close to inversion point (+4°C) section were investigated. The graphs of water temperature velocity distribution throughout the height of experimental section were constructed and analyzed. The results obtained allow estimating the impact of water temperature that is closely situated to inversion point on the dynamics of water ice melting and generation as well as on the form factors of cold accumulators. Such software and analytical research will allow increasing effectiveness and efficiency at the heat and bulk transfer equipment engineering.Документ Experimental and theoretical study of ice formation on vertical cooled pipes(2015) Zasiadko, Yaroslav; Pylypenko, Oleksii; Gryshchenko, Roman; Forsyuk, AndriyDynamics of ice accumulation on the surface at different ∆t (refrigerant evaporation temperature and the temperature of water that overflows surface) has been studied. Series of experiments have been carried out with 2 refrigerants (R12 and R22). The temperatures of water and that of refrigerant evaporation have varied within the intervals +1,5÷+4,50C; -10÷-200C, respectively. The mass flow rate and the velocity of water within the experimental sections were kept constant during a whole series of experiments. The ice-layer thickness was measured by means of optical method. The instantaneous images of the experimental pipe with the ice layer were processed with the graphic processing software.