For calculating and designing of photovoltaic (PV) plant, it is necessary to choose the optimal tilt angle and azimuth orientation of solar panels which will largely determine the electricity output produced by future PV plant during an operational calendar period. However, in order to determine these angles experimentally by monitoring the PV plant electricity yield at different panel’s positions, it will take many years. Therefore, it is advisable to develop a theoretical model, which a priori calculates the optimal tilt and azimuth angles of panels amounted in fixed positions. This paper assumes the maximum of the total radiation arrival per unit area on the receiving surface over the calendar period of PV plant operation as an optimization criterion for these angles. The calculation scheme has been applied for the whole year, for four year seasons and for a whole year period except winter. In the developed optimization method, the initial data are the geographical coordinates of the PV plant, the hourly sums of direct and diffuse radiation on the horizontal plane, as well as the reflectivity of the earth's surface. These data obtained by averaging the long-term measurements of the main solar radiation components are experimental ones. The developed computational scheme is based on nonlinear equations for the optimal tilt angles of panels first obtained for anisotropic solar radiation models. This scheme allows us to calculate the optimal panel angles for any operational PV plant period and for any region for which experimental radiation data are available. As the examples, we have calculated the graphs of the average daily radiation arrival dependencies on the panel’s position angles and have determined the optimal fixed tilt and azimuth angles for six cities of Russia located in different climatic zones. The method allows us to evaluate the gain in the electricity yield of PV plant when choosing the optimum tilt angles and azimuth of the panels, and to a djust the tilt angles to the optimum values for each season if this is envisaged by the PV string design.

The paper presents the project of the autonomous power complex on the basis of wind-power plant and hydrogen module with a capacity in 3 kW with further replication to 50 kW and shows the possibilities of operation of the present plant in different climatic conditions of Russia: Siberia, the Far East, the Northern Caucasus, Krasnodar territory, and also for universal use in climatic zones of the Arctic and Antarctic, deserts of Africa and the isolated islands with typical destructive sea salt fogs.

This paper carries out the study, comprehensive analysis and comparison of known types and classes of wind plants, as a result of which the authors have developed an innovative multi-tier scalable vertically-axial wind power plant. This unit is used as the main power source, the uninterrupted part of which is based on a cyclically operating hydrogen module, contains an electrolytic cell, a fuel cell system and a hydrogen storage device with a communication and control system. The components of the power plant developed by the authors’ team operate at a single DC voltage and can be connected to a common bus bar with an increase of power in this complex. Flexible control algorithms allow optimizing the operation of the power complex to reduce the start-stop frequency, thereby increasing both the service life and time intervals between maintenance. Remote control provides monitoring and management of electricity output processes and hydrogen storage with the help of Internet technologies in long-term modes.

The study has shown that this equipment is long-lived, reliable and environmentally friendly, and the system is modular and flexible because it is easily scaled under consumer’s control including the personal power consumption and small business. Moreover, the developed power plant is accessible in purchase, mounting and operation for remote energy consumers as far as the assessed value of equipment is correlating with the cost of power line installation and the operation of equipment does not require large engineering and technological skills.

The paper presents the results of the comparative analysis of operation modes of an autonomous hybrid power complex with/without the energy store. We offere the technique which defines the power characteristics of the main components of a hybrid power complex: the consumers of the electric power, wind power and photo-electric installations (the last ones have been constructed). The paper establishes that, in order to compensate the seasonal fluctuations of power in autonomous power systems with renewable energy resources, the accumulative devices are required, with a capacity of tens of MWh including devices that are capable to provide energy storage with duration about half a year. This allows abandoning the storage devices for smoothing the seasonal fluctuations in the energy balance.

The analysis of operation modes of energy stores has shown that for a stock and delivery of energy on time intervals, lasting several hours, the accumulative devices with rather high values of charging and digit power aren't required. It allows using the lead-acid rechargeable batteries of the deep category for smoothing the daily peaks of surplus and a capacity shortage. Moreover, the analysis of operation modes of energy stores as a part of the hybrid complexes has demonstrated that in charging/digit currents of the energy store the low-frequency and high-frequency pulsations of big amplitude caused by changes of size of output power of the renewable power installations and loading are inevitable. If low-frequency pulsations (the period of tens of minutes) can partially be damped due to the restriction of size of the maximum charging current of rechargeable batteries, then it is essentially impossible to eliminate high-frequency pulsations (the period of tens of seconds) in the power systems with the only store of energy. The paper finds out that the combined energy store having characteristics of the accumulator in the modes of receiving and delivery of power on daily time intervals, and at the same time having properties of the supercondenser in the modes of reception and return of impulses of power on second intervals of time is best suited to requirements of the autonomous power complexes with renewable energy resources.

The paper analyzes the problems of combustion hydrogen in an oxygen medium for produce high-temperature steam that can be used to produce electricity at various power plants. For example, at the nuclear power plants, the use of a H2-O2 steam generator as part of a hydrogen energy complex makes it possible to increase its power and efficiency in the operational mode due to steam-hydrogen overheating of the main working fluid of a steam-turbine plant. In addition, the use of the hydrogen energy complex makes it possible to adapt the nuclear power plants to variable electric load schedules in conditions of increasing the share of nuclear power plants and to develop environmentally friendly technologies for the production of electricity. The paper considers a new solution of the problem of effective and safe use of hydrogen energy at NPPs with a hydrogen energy complex.

Technical solutions for the combustion of hydrogen in the oxygen medium using direct injection of cooling water or steam in the combustion products have a significant drawback – the effect of “quenching” when injecting water or water vapor which leads to a decrease in the efficiency of recombination during cooling of combustion products that is expressed in an increase fraction of non-condensable gases. In this case, the supply of such a mixture to the steam cycle is unsafe, because this can lead to a dangerous increase in the concentration of unburned hydrogen in the flowing part of the steam turbine plant. In order to solve this problem, the authors have proposed a closed hydrogen cycle and a hydrogen vapor overheating system based on it, and carried out a study of a closed hydrogen combustion system which completely eliminates hydrogen from entering the working fluid of the steam cycle and ensures its complete oxidation due to some excess of circulating oxygen.

The paper considers two types of hydrogen-oxygen combustion chambers for the system of safe generating of superheated steam using hydrogen in nuclear power plant cycle by using a closed system for burning hydrogen in an oxygen medium. As a result of mathematical modeling of combustion processes and heat and mass transfer, we have determined the required parameters of a hydrogen-oxygen steam generator taking into account the temperature regime of its operation, and a power range of hydrogen-oxygen steam generators with the proposed combustion chamber design.

This study is related to the electrochemical oxidation of NaBH4 on Au, Pt, Pd and Ni electrodes by the use of cyclic and square wave voltammetry. The most effective metal for the oxidation of sodium borohydride was found to be Au. Pt and Pd electrodes also showed certain activity while Ni was not effective. The compound was observed to give two consecutive oxidation steps with 6 and 2 electron transfers. The experiments conducted while keeping the potential at −0.8V showed that the resulting compound is adsorbed upon the electrode surface and gradually decrease its catalytic activity.

The paper considers a non-equilibrium poroelectroelastic theory of a polymer electrolyte under the conditions of water electrolysis with the purpose of further use for a theoretical description of mass transfer processes in l ayers of a membrane-electrode assembly. Moreover, this paper carries out the review and analysis of the models of electro- chemical and mass-exchange processes in the electrolyzers, and analyzes the problems of their physicochemical description. We make a conclusion about the need to use models of water sorption and scaling of polymer electrolyte and analyze the models of water sorption and swelling of the polymer electrolyte. It is concluded that the existing poroelectroelastic theory is the most suitable for its modification for use in non-equilibrium conditions during elec- trolysis. The basic equation of the balance of pressures of the classical equilibrium poroelectroelastic theory for polymer electrolyte is considered. A modification of the poroelectroelastic theory has been carried out in order to its use in non-equilibrium conditions of water electrolysis for the purpose of further modeling of mass transfer processes. Based on experimental data available in open sources, the paper makes an analysis of the properties and features of elastic forces in the polymer electrolyte, and then refines the dependencies of the elastic forces in the polymer electro- lyte from the swelling and temperature. Taking into account the existing experimental data on the permeability of gases in a polymer electrolyte and the feature of swelling of the polymer electrolyte in a contact with liquid water, parameters of the non-equilibrium poroelectroelastic theory have been obtained for the water electrolysis conditions.

In this study, a parametric investigation is carried out to estimate the hydrogen energy potential depending on the quantities of H2S in Black Sea deep waters. The required data for H2S in Black Sea deep waters are taken from the literature. For this investigation, the H2S concentration and water layer depth are taken into account, and 100% of conversion efficiency is assumed. Consequently, it is estimated that total hydrogen energy potential is approximately 270 million tons produced from 4.587 billion tons of H2S in Black Sea deep waters. Using this amount of hydrogen, it will be possible to produce 38.3 million TJ of thermal energy or 8.97 million GWh of electricity energy. Moreover, it is determined that total hydrogen potential in Black Sea deep waters is almost equal to 808 million tons of gasoline or 766 million tons of NG (natural gas) or 841 million tons of fuel oil or 851 million tons of natural petroleum. These values show that the hydrogen potential from hydrogen sulphur in Black Sea deep water will play an important role to supply energy demands of the regional countries. Thus, it can be said that hydrogen energy reserve in Black Sea is an important candidate for the future hydrogen energy systems.

The traditional methods for production of Ме^IV-V aluminides are laborious, long-lasting and multi-stage. The Laboratory of High-Temperature  Synthesis and Technology of Inorganic Compounds has developed a new highly efficient  method for obtaining alloys and intermetallides of refractory metals, the “hydride cycle” (HC) method. This review presents the results of systematic studies of HC-formation of aluminides in the systems TiH₂–Al, ZrH₂–Al, NbH_1,23–Al, TiH₂–Al–ZrH₂, TiH₂-Al-NbH_1,23. The review describes the influences on this process of such parameters,  as chemical characteristics of hydrides, the ratios of the initial components, phase transformations, etc., and  proposes a mechanism for the HC-formation of aluminides of IV-V groups metals: upon heating of compacted хМеH₂+(1-х)Al→Ме_хAl_1-х+Н₂↑, the hydrogen dissociates from the hydride; in the environment of the liberated hydrogen, the oxide film is removed; a very active metals are formed, which instantly interact with aluminum exothermically  by a solid-phase mechanism without aluminum melting. We have synthesized in HC more than 30 aluminides: single-phase α₂-Ti₃Al, γ-TiAl и TiAl₃; solid solutions of Al in Zr: Zr₃Al, single-phase ZrAl_2, ZrAl₃ and Zr₃AlH_4.49 hydride; single-phase NbAl₃ , Nb₂Al and Nb₃Al, containing about 10% Nb₂Al; Ti_0,35 Zr_0,4Al_0,25; Ti_0,55Zr_0,2Al_0,25; Ti_0,25Al_0,5Nb_0,25; Ti_0,45Al_0,28Nb_0,27, Ti_0,2Zr_0,05Al_0,75; Ti_0,2Zr_0,05Al_0,75, etc. Without preliminary crushing, some aluminides interact with hydrogen in the SHS mode forming reversible hydrides. Based on the obtained results, two concentration triangles for Ti-Al-Zr and Ti-Al-Nb systems were constructed. Compared with existing methods, the synthesis in HC of aluminides of IV and V group metals has significant advantages: relatively low temperatures (~ 1000°C) and short duration (30-60 min) of process; formation in one technological stage, without melting of the original components; environmentally friendly and energy-saving, economically viable, etc. Synthesis of trialuminides occurs at temperatures of 650-670ºC. Aluminides based on Me^IV-V groups are very promising construction materials, they are used in aerospace and ground machine-building, defense industry, chemical and food industry,  electronics, as biocompatible materials in medicine, etc.

The paper gives the investigation results of composition and morphology of oxide nanostructures of transition metals – zirconium, molybdenum and wolfram synthesized by laser ablation pure metals in water.

High temperatures and pressures in zone of interaction of the pulse laser beam with the surface of metal in water contribute to the intensive synthesis of oxides in the form of clusters of particles with size about 1−2 nanometres. This is characteristic for metals with high ionization potential. As it follows from the data of X-ray diffraction analysis and scanning electron microscopy, specifically, the clusters are amorphous building material for nanostructures of the oxides of the metals enumerated above. The paper demonstrates the general pattern of their structure, namely, the stratification of the material from which the foam formations, thin-walled hollow round particles, plates, filaments, and other forms of nanostructures are composed. The research of morphological features of the nanostructures of zirconium, molybdenum and wolfram oxides obtained by the authors indicates that their use as substrates will achieve high gain values of Raman scattering ~ 10⁴−10⁸. In this range, there are the gain data previously obtained by the authors in the experiments on the synthesis of zirconium nano-oxides when using them as a substrate.

This indicates that the nanostructures of molybdenum and wolfram nano-oxides also can serve as the effective substrates and can be used as a sensor in the high sensitive composition of substances analyzers based on surface enhanced Raman scattering.

The paper is devoted to the problem of determining the higher harmonics presence in a power network. The paper notes the negative influence of higher harmonics of voltage and current on the power supply system’s elements and communication lines. During the research, a device has been developed to analyze the higher harmonics of the power network. The main element of the device is the Arduino board on the Atmega328p microcontroller. For the correct operation of the device, the corresponding software has been created. The result of modeling of the proposed device operation is a set of harmonic values of the investigated signal in a form suitable for further analysis.

Review of New Scientific Books