Yuri Gagarin State Technical University of Saratov

Electricity consumption is uneven during the day.NPP operation is most efficient in the mode of maximum installed capacity utilization factor due to high total capital investments with a low share of fuel costs.Electricity storage systems based on hydrogen technologies can be used to ensure high installed capacity utilization factor.The paper presents a comprehensive study of the hydrogen energy complex with a closed fuel cycle in combination with NPPs developed by the authors.Based on the adaptation of the methodol. for comparative assessment of the efficiency of energy complexes at NPPs, a system of specific indicators has been developed.This system allows determining the comprehensive efficiency of power plants by adding up specific indicators characterizing the effects achieved during their operation in relation to the funds invested in them.In addition, a specific indicator has been developed characterizing the effect of reducing hydrogen underburning due to the implementation of a closed hydrogen combustion cycle.A comparative assessment of the efficiency of the hydrogen energy complex with a closed fuel cycle has been carried out, and the conditions for its economic efficiency have been shown.The main tech. and economic indicators and conditions of economic superiority of the hydrogen energy complex over alternative options are determinedThe advantage of the hydrogen energy complex in terms of accumulated net present value in comparison with the sale of electricity to the grid reaches 38.34 mln. $.With a 50 % increase in the cost of capital investments in the hydrogen energy complex, the high thermodn. efficiency allows maintaining competitiveness in comparison with the sale of electricity to the power grid, but it is significantly reduced.The min. value of hydrogen underburning, at which it is advisable to implement measures to reduce underburning, is determined, depending on electricity tariffs and the cost of measures to reduce underburning.Based on the calculated data obtained, an anal. of the effect of completeness of hydrogen fuel combustion on the specific efficiency indicators of the hydrogen energy complex is carried out.The specific indicator of the efficiency of measures to reduce underburning is determinedIt is shown that even taking into account the increased cost of capital investments in the hydrogen energy complex, a competitive advantage is ensured in comparison with pumped storage power plants in almost the entire studied range of electricity tariffs and capacity charge.

In this paper, the effect of aluminosilicate microspheres (ASMs) from thermal power plant (TPP) ash on the properties of epoxy composites was studied. A method for modifying the ASMs' surface using aminoacetic acid was developed to improve the adhesion at the polymer-filler interface. Complex analysis methods, including scanning electron microscopy, infrared spectroscopy, a thermogravimetric analysis, DSC, and DMA, showed that adding the optimal amount of ASMs significantly improved the physical and mechanical properties of the composites: the flexural strength increased by 112%, the elastic modulus by 198%, and the impact strength by 50%. Functionalization of the ASMs enhances their interaction with the matrix, providing the composites with the best strength and thermal stability indicators among the studied materials. The study of the curing kinetics showed the initiating effect of functionalized ASMs on the curing process of epoxy compositions, associated with the presence of active amino groups on the surface of the particles. The resulting composites demonstrate potential for application in structural and fire-resistant materials; have high-deformation and -strength characteristics; and facilitate the disposal of industrial waste.

The influence of ultrasonic vibrations of the tooling on the heating kinetics of polymer composite materials (PCM), fabricated by the FDM technol. from the filaments reinforced with continuous carbon fibers and single-component polymers used as binders, is studied.The ultrasonic frequency is shown to considerably affect the temperature of a sample in the region of its contact with the tool.It is noted that in the case of a high-performance engineering thermoplastic material-PEEK-used as a binder, an increase in the vibration frequency exerts a stronger influence on the temperature value.The time of exposure to ultrasound has a stronger impact at higher frequencies (in the studied range).A twofold increase of the vibration frequency, the other factors being similar, provides a 6.0-30.9% increase of the PCM heating temperature and an 8-71% increase of the polymer heating temperature, depending on the binder material.