The temperature dependences of the electrical conductivity of non-irradiated and gamma-irradiated In_0,99Sm_0,01Se and In_0,99Er_0,01Se single crystals in the temperature range 125-300K have been studied. From the experimental data, it was revealed that when single crystals are irradiated with ã-quanta with a dose of 100 krad, uncontrolled defects are treated and the concentration of nonequilibrium charge carriers increases. That is, radiation leads to the perfection of crystals, which is an important factor for the efficient use of these materials in industrial electronics. The study of electrical conductivity makes it possible to determine the energy levels of defects in non-irradiated and gammairradiated In_0,99Sm_0,01Se and In_0,99Er_0,01Sе. single crystals.

It has been established that when single crystals of In_0,99Sm_0,01Se and In_0,99Er_0,01Se solid solutions are irradiated with a dose of 100 krad at low temperatures, the dependence ó_Т( ã) is not related to the heating of charge carriers by an electric field. The difference in the temperature dependence between unirradiated and irradiated crystals at low temperatures depends on the thermal depletion of defect centers, while at high temperatures the concentration of defect centers increases.

The activation energies were determined from the temperature dependences of electrical conductivity for nonirradiated and irradiated single crystals of In_0,99Sm_0,01Se and In_0,99Er_0,01Se solid solutions with a dose of 100 krad. It has been established that for a single crystal of the In_0,99Sm_0,01Se и In_0,99Er_0,01Se solid solution that was not irradiated and irradiated with a dose of 100 krad, the activation energies were, respectively, Е_an^ir =1,1eV and E_ai^r =0,56eV. For single crystals of In_0,99Er_0,01Se solid solutions, the activation energy does not change after irradiation. The activation energies determined from the slope of the temperature dependences of the electrical conductivity in non-irradiated and irradiated In_0,99Er_0,01Se crystals are the same and equal to Е_an^ir = E_ai^r =0,63 eV.

The paper considers the task of creating an instrumental system for optimizing the exchange of active power of the trunk and distribution networks, taking into account the price indicators of electricity (EE) in a joint and separate mode of operation. As part of the development of a simulation model of the automated control system of the local intelligent power system (LPS) MicroGrid, the results of modeling the exchange of active power of the power connection from the main network of the MEP of the South and the distribution network of the university campus are presented.

The active power exchange module created on the basis of the results of the simulation as part of the RETREN software package will make it possible to use this complex to automate the management of LPS.

The growing energy needs of mankind lead to the need to search for and develop technologies for renewable energy sources. Along with this, the issue of disposal of a large amount of organic waste generated as a result of human activity remains relevant. Methods of biodegradation of wastes with simultaneous production of bio-fuels based on anaerobic digestion processes have become widespread. Recently, a process of direct interspecies electron transfer (DIET) between syntrophic bacteria and methanogenic archaea has been discovered, which does not depend on metabolic intermediates. It also became known that it is possible to stimulate the transfer of electrons between microorganisms using electrically conductive materials of an abiogenic nature, increasing the overall yield of biomethane. Previous studies have shown the possibility of increasing the efficiency of two-stage anaerobic digestion by adding various stimulating materials. In this work, we studied a model of two-stage anaerobic digestion with time-separated stages in one reactor due to the enrichment of the microbial community with the thermophilic hydrogen-producing bacterium Thermoanaerobacterium thermosaccharolyticum SP-H2. The medium was supplemented with 10 mg/L of ferrous sulfate (II) to stimulate hydrogen production, and 10 g/L of granular activated carbon (GAC) was added for activation of direct interspecies electron transfer (DIET). This work aimed to test the method of sequential production of hydrogen and methane in one reactor by simultaneously maintaining a low pH to reduce the activity of methanogens, and adding soluble iron (II) sulfate and GAC to activate hydrogenases and DIET, respectively. The experiment was carried out in sealed glass vials with a volume of 120 ml at a temperature of 55°C (thermophilic temperature regime). The thermophilic digested sewage sludge obtained from the Lyubertsy and Cherepovets treatment facilities (methanogenic) and the culture of anaerobic thermophilic bacterium T. thermosaccharolyticum SP-H2 (hydrogenogenic) were used as inoculums. The successive production of hydrogen and methane was observed in the batches that contained both GAC and ferrous sulfate (II). The efficiency of the process was estimated using the modified Gompertz equation. According to the data obtained by scanning electron microscopy, active biofouling was observed on the particles of granular activated carbon taken from the GAC-Fe vials, covering all cavities and protrusions of the surface. Syntrophic conversion of metabolite products along with positive effect of ferrous sulfate (II) on hydrogenase activity can be assumed based on the obtained data. Thus, the tested original strategy of sequential production of hydrogen and methane in one reactor due to the separation of stages in time is promising for further study and application, including with the use of a real substrate.

Among renewable energy sources, hydrogen and methane are gaseous fuels that have a higher energy density than petroleum-derived gasoline and diesel. In recent years, there has been increasing interest in converting existing anaerobic digestion systems to a two-stage process that results in the production of hydrogen in the first stage and then the production of methane in the second stage. In this study, an assessment was made of the energy yields of a two-stage process of mesophilic-thermophilic anaerobic fermentation of native cheese whey. Cheese whey was fed into a mesophilic acid reactor at three CODs of 6.8 g/l, 9.2 g/l and 13.8 g/l with a hydraulic retention time (HRT) of 10 hours. The acidogenic reactor effluent was then fed to three methanogenic reactors, which operated at different HRTs: 72, 48, and 24 hours. The working volumes of the reactors were 900 ml each. Polyurethane foam was used to immobilize the anaerobic acidogenic and methanogenic sludge. The heating value (HV) was determined according to the measurement method using a bomb calorimeter for modes with the highest methane content and with the highest hydrogen content, as well as a calculation method based on the content of combustible gases in biohythane. The obtained deviations of the calculated HV value of biohythane from the experimentally determined HV value (2.51–7.11%) could be due to the fact that the HV value of biohythane is probably not equal to the sum of the HV values of hydrogen and methane. While an increase in the hydrogen content in biohythane leads to a decrease in the deviation of the calculated and experimental HV values of biohythane. The maximum energy production rate (EPR) was 53.2 kJ/(l day) at a COD concentration in the influent of 13.8 g/l, a hydraulic retention time (HRT) in an acidogenic reactor of 10 h, and a HRT in a methanogenic reactor of 48 h. The maximum energy yield (EY) (14,42 kJ/g COD) was observed at a COD concentration in the influent of 9.2 g/l, HRT in an acidogenic reactor for 10 h and HRT in a methanogenic reactor for 72 h.

The relevance of the study is due to the high-energy consumption of precision air conditioning units.

This study examines the issue of automatic regulation and control of precision-type air conditioning systems and its interaction with thermal processes occurring in the serviced room. Based on the design of both existing and newly introduced air conditioning systems in a building, it always assumes one or another optimization of the engineering decisions taken. However, this problem has recently become particularly important due to a sharp increase in the requirements for materials and the energy intensity of ACondS and the degree of security of the specified parameters of the air environment under variable external and internal influences. In addition, a significant expansion of the choice of equipment for ACondS, which in some cases leads to difficulties in finding the optimal option, also requires new approaches to the calculation, design and operation of ACondS and their automatic control systems.

The existing methods for calculating and analyzing the state of the air environment in a room have a number of drawbacks, since they either do not take into account some significant factors affecting the heat and humidity balance of a room, or are cumbersome and therefore unsuitable for engineering practice. In addition, both of them do not yet reflect the relationship between the dynamic characteristics of technical means of automation and AContS devices with the processes in the room.

The calculation of the non-stationary thermal regime of the room, taking into account the automatic control of the ACondS elements, is complicated by the relationship and mutual influence of transient physical processes both in the room itself and in the ACondS elements serving it and in automation equipment.

Therefore, it is necessary to develop such methods for calculating the thermal regime of a room, ACondS and AContS, which would be relatively simple to use and at the same time take into account to a sufficient extent the relationship between the processes occurring during the ACondS regulation.

Another important factor is the growing requirements for the annual reduction of energy resources for state-owned enterprises, as there is a constant increase in the cost of heat and electricity consumed by the engineering systems of residential and public buildings, which leads to the need to optimize design solutions and control algorithms for air conditioning and ventilation systems. According to various studies, the energy demand for air conditioning and ventilation, while providing standard air exchange, is more than 60% of the total energy consumption. The analysis of possible solutions should be based on the results of solving the optimization problem of the objective function, which is a convolution of operating and capital costs.

In this regard, this article is aimed at revealing the possibilities of regulating the fan units of the air conditioning system.

The main approach to the study of this problem is the development of quality control systems for air conditioning systems.

The relevance of the study is due to the low efficiency of using the heat of combustion of fuel in modern industrial, energy and heating installations.

This article is aimed at improving energy efficiency in the design of trinegeration installations, as well as improving existing trigeneration systems.

The existing installation has a highly efficient approach in the energy sector, which is aimed at the one-time production of electricity, heat and cold from a local centralized location. A popular technological solution for creating trigeneration systems is a combination of gas-piston power plants and absorption chillers, in which the energy of the exhaust gases is used to generate cold.

In this regard, this article is aimed at revealing the possibilities of using the heat of the exhaust gases of the cogeneration plant, including the latent heat of the formation of water vapor contained in the flue gases.

In this study, the key component is the method of utilization of hot exhaust gases of a gas turbine system, which in turn consists in the transfer of heat from hot gases through a steam compression heat pump that provides regenerative heat exchange.

The temperature of the hot gases that come out of the gas turbine can be about 450oC, and these gases usually contain a sufficient amount of heat, which makes heat recovery economically feasible. As a rule, the output gases are fed into an indirect contact heat exchanger containing water that evaporates. The resulting water vapor is fed to a steam turbine connected to a generator that produces electricity, and the expanded steam exits the turbine. The expanded steam condenses in a condenser, which is usually supplied with cooling water from a reservoir connected, for example, with a grate.

During cold weather, the air temperature may fall below the freezing point of the water, leading to freezing of the cooling water and steam condensate, thus preventing the operation of the condenser and cooling tower. When this happens, the operation of the heat recovery cycle should stop.

The main approach to solving this problem is the utilization of the heat of the exhaust gases of the co-generation plant using a steam compressor heat pump, which in turn increases the energy efficiency of the trigeneration of the cogeneration plant by reducing exergetic losses. To analyze the effectiveness of the cycle, the method of exergetic analysis was used.

The materials of the article are of practical value for designers of integrated heat supply systems.