The paper offers a thermal model to determine the specific heat productivity of flat-plate solar water-heating collector (FSWHC) depending of the pre-assigned temperature values of obtaining hot water. Unlike existing thermal models of FSWHC, for the first time in the proposed model the research results obtained by the authors are used to determine the average mass temperature of the heat-transfer (water) collectors, heat efficiency coefficient and the surface average working temperature of the light-absorbing heat-exchange panels (LAHP) by non-contact method, depending of the effective coefficient of LAHP heat losses. In order to determine the coefficient we have to take into account the partial absorption influence and conversion into heat of the total solar radiation passing through translucent cover of collector case and also the value of the LAHP surface average working and ambient temperature. It is provided a practical example of realization and proved authenticity of the model.

The paper describes the simulation modeling of autonomous solar lighting system based on photovoltaic cells, energy storage battery and power consumer in the form of LED lamps. The aim of research is to develop a model what allows to explore a system behavior (changes in voltages, currents and battery state of charge) under controlled conditions like solar intensity, photovoltaic converter efficiency and lighting load power. The research includes the testing of model under different load power conditions at the same solar power and battery charge capacity. Testing results have proved the adequacy of model. The proposed model can be used for studying the charge/discharge processes in the different types of batteries for such energy systems including solar and wind renewable sources.

The paper deals with the principles of operation, experimental characteristics, functional charts of electric generator on the base of synchronous reactive machine with independent excitation, and draws a comparison between this generator and another ones. Moreover, the paper focuses special attention to high specific parameters and good exploitation characteristics of these electric generators. We show data to prove the adequacy of experiments. The high accuracy of supporting the specified voltage under efficient mass-weight parameters is being provided by small power of control chains in excitation channel while its high performance.

Method of two-stage pyrolytic biomass processing, combining the feedstock pyrolysis and subsequent heterogeneous cracking of volatile pyrolysis products in charcoal bed, provides a high degree of energy conversion of feedstock into gas with a higher calorific value of 11–12 MJ/m3. The paper deals with the possibility of using the raw gas (without purification from tars) as a fuel for power generation plants based on the internal combustion engine. The paper presents experimental data on the specific content of tar and moisture in the product gas and their dependence of the processing parameters. Moreover, it analyzes potential mechanisms for increasing of the product gas volume which is observed with increasing of the cracking zone temperature.

The article deals with the methodology of complex foundation and optimal choice of composition and parameters of equipment of hybrid energy complex (EC) based on renewable energy and traditional energy sources. Optimization is made by criteria of energy and economic efficiency. The experimental studies are in numerical simulation of selection process of equipment composition. For estimate calculation with a lack of initial information, simulation is performed in Microsoft Excel. For accurate optimization calculation using detailed initial information, the simulation dynamic model is developed in the environment of MATLAB Simulink.  The methodology determines the optimal composition and parameters of the EC equipment based on renewable energy for power supply valve stations in real placement of gas pipeline under construction, that allow us to replace electricity consumed with renewable energy 93,5 % for a year. The economic efficiency of the projectissubstantiated. The methodology and calculation models can take into account the additional conditions and restrictions, the original data and models of energy converters, which give the flexibility and versatility to the methodology and calculation models.  Using the methods and guidelines in the design phase will increase the competitiveness and cost effectiveness of the EC based on renewable energy sources, and optimize the total cost of electric supply low power autonomous consumers. 

The paper presents an historical review of the use of nuclear explosions for peaceful purposes in the Soviet Union, the basic principles of the Soviet Program for Peaceful Uses of Nuclear Explosions, the key feature of which is an interindustry character. The characteristic properties and the advantages of contained nuclear detonations as well as underground explosionswith external action have been studied in the paper. The authors consider the types of the process area where nuclear explosions have been carried out. Moreover, the manufacturing quality of nuclear charges has been taken into consideration.

The paper deals with the feasibility of problem of hydrogen obtaining from associated hydrocarbons at the geothermal wells in the territory of the Eastern Caucasus and Ciscaucasia. Exploration data indicate the presence of large reserves of water dissolved methane in this territory, where one well methane yield debit from 2000 m³ to 3000 m³ per day is, on average, from 1000 m³ to 4000 m³ per day. It is shown that this creates both economically and environmentally more favorable conditions for the hydrogen production at the well along with the use of thermal energy of underground thermomineral waters. The paper presents the installation scheme for waste thermal energy of geothermal water and casing-head gases utilization with the possibility of hydrogen production by methane conversion directly in the well.

The paper describes the preparation and study of carbon-graphene composites on the basis of graphene-like material (GLM) and carbon nanofibers (CNF). CNF/GLM composites were prepared through pyrolysis of ethylene on a Ni-containing catalyst, supported on the surface of the GLM. Ni-containing catalysts were prepared by two methods: (1) hydrothermal treatment of aqueous suspension of graphite oxide and nickel acetate, followed by heating in a hydrogen stream; (2) hydrogen reduction of pre-formed Ni(CH₃COO)₂/GO composite. CNF synthesized on the surface of GLM had a diameter of 10 nm and a length from 10 to 300 nm at the synthesis duration from 1 to 60 min. The received material can be used as a carrier of catalysts for organic synthesis, reversible sorption of hydrogen and the electrochemical sources of current.