• Energy Research
• RU close

This article discusses application of nanomodified heat accumulators on the basis of paraffin modified by carbon nanostructures for various technological processes aiming at increase in their energy efficiency. Thermal and physical properties of nanomodified paraffins have been studied. Procedure of adaptation of heat accumulating materials for various operation modes of industrial processes is presented. Copyright © EM International.

Барбасова Татьяна Александровна, канд. техн. наук, доцент, Высшая школа электроники и компьютерных наук, Южно-Уральский государственный университет, г. Челябинск; barbasovata@susu.ru. T.A. Barbasova, barbasovata@susu.ru South Ural State University, Chelyabinsk, Russian Federation ; В работе рассмотрены вопросы повышения эффективности оперативного управления распределенными технологическими сетями тепло- и пароснабжения производственных металлургических комплексов на основе динамического макромоделирования режимов сетей при структурных переключениях и резко переменных нагрузках. Предлагается осуществлять решение задач стабилизации потоков ресурсов в технологической сети на основе решения уравнений обратных задач динамики сети и использования расчетных контуров парирования потоковых возмущений. Алгоритмы парирования потоковых возмущений в технологической сети целесообразно строить с использованием обратных моделей динамики путей передачи входных управляющих потоков к входным узлам потоковых возмущений в сети. Предложена программная макромодель, позволяющая моделировать статические и динамические режимы систем паро- и теплоснабжения, управление зарядно-разрядными процессами паровых аккумуляторов. В данной модели регулируемым параметром является давление пара в аккумуляторе. Ограничение давления пара в аккумуляторе осуществляется с помощью специального регулятора давления, который настраивается на минимум потерь пара на свече при его избытке в сети. Данная программная макромодель позволяет моделировать работу потребителей с резко выраженной переменной нагрузкой. The paper seeks to increase efficiency of operational control of distributed technological heat and steam supply networks in metallurgical production complexes based on dynamic macro-modeling of network modes under structural switching and sharply variable loads. It suggests solving problems of resource flows stabilization in a technological network by solving the equations of inverse problems of network dynamics and using calculated contours of stream ...

One of the ways the accumulation of solar energy is water and decomposition of electrolytic hydrogen production. In this paper is presented an alternative method of accumulation of solar energy by getting fuel biojetanolnogo. It is shown, that application of the technology of biothermal ethanol is promising by synchronizing the schedules of the parishes of energy from the Sun and its consumers. Одним из путей аккумуляции солнечной энергии, является электролитическое разложение воды и получения водорода. В данной работе представлен альтернативный метод аккумуляции солнечной энергии путем получения биоэтанольного топлива. Показано, что применение технологии биотермического получения этанола является перспективным путем синхронизации графиков приходов энергии от солнца и использования ее потребителями.

One of the main tasks in designing heat accumulators for renewable energy installations is accurately calculating the temperature and energy intensity of the heat accumulator. In recent years, based on the use of modern technologies, it has become possible to obtain building materials with high characteristics of the heat-accumulating medium. In order to increase the efficiency and reliability of heat accumulators, as well as the optimal choice of elements for building structures, there is a need to improve methods for calculating their operating modes based on the creation of numerical models. The article considers the principles of creating heat accumulators based on various heat storage media. Based on the system of differential equations of motion of the coolant and thermal conductivity, a mathematical model of the solar heat accumulator is constructed and a program for its numerical solution is developed. The fields of temperature distributions inside an underground heat accumulator with different warm-up times were obtained and the average daily temperature of the working fluid of the heat accumulator based on gravel and zeolite was determined. It is shown that in comparison with a gravel accumulator, the energy efficiency of a zeolite is twice as high, and the volume of the chamber of a zeolite accumulator can be twice as small as a gravel one with the same efficiency of its operation. Recommendations are given on the selection of various heat storage materials, with an assessment of their applicability and availability. The subject of research: methods for calculating the temperature and energy consumption of elements of building structures of heat accumulators. Objectives: improvement of methods for calculating the temperature and energy consumption of building elements of heat accumulators. Materials and methods: the proposed method is based on the possibility of creating a numerical model of a heat accumulator heated by solar radiation to simulate the dynamics of changes in the average temperature of the heat accumulating material over time. Results: A theoretical calculation of the temperature and energy consumption of the heat accumulator is proposed. Conclusions: the approach proposed in this article can be applied to energy construction.

The article discusses processes of thermal energy storage. The present invention relates to the thermal energy accumulators, periodically rechargeable from the electrical energy at a predetermined time, for example, when using the cheaper night rate electricity and release of heat energy to consumers at their request at other times of the day. As a high-temperature working fluid used graphite blocks with channels for gas flow, and the heat transfer gas is carbon dioxide at temperatures above 125 °C. В настоящей статье рассмотрены процессы аккумулирования тепловой энергии. Представленное изобретение относится к аккумуляторам тепловой энергии, заряжаемым от электрической энергии периодически в заданное время, например, при использовании более дешевого ночного тарифа за электроэнергию и отдачу тепловой энергии потребителям по их требованию в другое время суток. В качестве высокотемпературного рабочего тела использованы графитовые блоки с каналами для потока газа, а в качестве теплопередающего газа – углекислый газ при температурах выше 125 °С.

This paper has experimentally proved that hydrogen accumulates in large quantities in metal-ceramic and pocket electrodes of alkaline batteries during their operation. Hydrogen accumulates in the electrodes in an atomic form. After the release of hydrogen from the electrodes, a powerful exothermic reaction of atomic hydrogen recombination with a large energy release occurs. This exothermic reaction is the cause of thermal runaway in alkaline batteries. For the KSL-15 battery, the gravimetric capacity of sintered nickel matrix of the oxide-nickel electrode, as hydrogen storage, is 20.2 wt%, and cadmium electrode is 11.5 wt%. The stored energy density in the metal-ceramic matrix of the oxide-nickel electrode of the battery KSL-15 is 44 kJ/g, and in the cadmium electrode it is 25 kJ/g. The similar values for the KPL-14 battery are as follows. The gravimetric capacity of the active substance of the pocket oxide-nickel electrode, as a hydrogen storage, is 22 wt%, and the cadmium electrode is 16.9 wt%. The density of the stored energy in the active substance oxide-nickel electrode is 48 kJ/g, and in the active substance of the cadmium electrode it is 36.8 kJ/g. The obtained results of the accumulation of hydrogen energy in the electrodes by the electrochemical method are three times higher than any previously obtained results using the traditional thermochemical method.

The energy storage field is nowadays a highly ranking topic. This research deals with the installation and analysis of the ice storage system which combines heat pump, solar absorber, and ice storage tank (phase change material—PCM). This system uses a special kind of solar absorber – header pipes (HDP), which have no thermal isolation compared to the common solar absorber. Thanks to that the HDP, pipes can absorb thermal energy not only from the sun but also from the environment. The rain or snow also affects heat exchange. All that is provided by one technical device. The system can store thermal energy gained from the solar absorber into the ice storage tank for future usage. Research works with data from the real operation, for a period of the year covering all working phases/modes of the system. The analysis of the data led to the identification of several specific modes of the system, especially from the processes taking place in the PCM storage tank during its charging and discharging at various time stages of operation of the whole system. The installation and analysis of the ice storage system probably took place for the first time in Slovakia and Slovak Republic’s conditions. Besides, this system was not installed on a new low-energy house, but on an older family house with thermal insulation. The aim of this installation was also to demonstrate the usability of the ice storage system in an older house and potentially reduce the homeowner’s fees thanks to new technology with higher efficiency. We managed to comprehensively analyze and describe the operation of this system, which also appears to be highly efficient even in a family house with a lower energy certificate, than today’s new low-energy buildings. The results showed a significant efficiency difference in favor of the ice storage system compared to conventional heating systems. The total analysis time was 1616 h and the total efficiency of this heating system—the seasonal coefficient of performance (SCOP) was 4.4. Compared to the average SCOP 3.0 of conventional heating systems for new low-energy houses, the total efficiency increased by 46.6%. These results could therefore be considered as beneficial, especially if we take into account that this system was installed on an approximately 40-year-old family house. The analyzed ice storage system is still working today. The main goals of this paper were to describe the heat pump’s duty cycle with ice storage (PCM) based on real-life data and bring a detailed description of the heat transfer medium behavior at various phases of storing/utilizing heat in the vertical ice storage’s profile for increasing efficiency.

Renewable energy is considered the one of the most promising solutions to meet sustainable development goals in terms of climate change mitigation. Today, we face the problem of further scaling up renewable energy infrastructure, which requires the creation of reliable energy storages, environmentally friendly carriers, like hydrogen, and competitive international markets. These issues provoke the involvement of resource-based countries in the energy transition, which is questionable in terms of economic efficiency, compared to conventional hydrocarbon resources. To shed a light on the possible efficiency of green hydrogen production in such countries, this study is aimed at: (1) comparing key Russian trends of green hydrogen development with global trends, (2) presenting strategic scenarios for the Russian energy sector development, (3) presenting a case study of Russian hydrogen energy project «Dyakov Ust-Srednekanskaya HPP» in Magadan region. We argue that without significant changes in strategic planning and without focus on sustainable solutions support, the further development of Russian power industry will be halted in a conservative scenario with the limited presence of innovative solutions in renewable energy industries. Our case study showed that despite the closeness to Japan hydrogen market, economic efficiency is on the edge of zero, with payback period around 17 years. The decrease in project capacity below 543.6 MW will immediately lead to a negative NPV. The key reason for that is the low average market price of hydrogen ($14/kg), which is only a bit higher than its production cost ($12.5/kg), while transportation requires about $0.96/kg more. Despite the discouraging results, it should be taken into account that such strategic projects are at the edge of energy development. We see them as an opportunity to lead transnational energy trade of green hydrogen, which could be competitive in the medium term, especially with state support.

Given the energy crisis and climate change due to pollution, and given that the largest emissions of greenhouse gases are produced by the energy industry, we must turn our attention to the efficient use of solar energy, which is the cleanest and most abundant of all renewable energies. In this paper, based on an analysis of the specialized literature, we studied the effect of dust accumulation on the surface of photovoltaic modules on some performance characteristics and on the efficiency of these panels and modules compared to the efficiency of clean modules. We analyzed the cause of dust accumulation and the influence of the tilt angles of the photovoltaic panels on the dust deposition rate. We highlighted the influence of atmospheric temperature, solar radiation, wind speed, and relative humidity depending on the density of the dust deposited on the surface of the photovoltaic panel, and we found a decrease in the efficiency of the panel based on the increase in dust density for slightly high values of solar radiation, wind speed, and relative humidity. We highlighted the reduction in CO2 emissions by replacing electricity from fossil fuels with solar energy. The efficient use of solar energy is a solution for the decarbonization of the energy sector.