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The gas engine driven carbon dioxide heat pump designed for providing the heat, cold and electricity for industrial poultry house is proposed. The scheme differs from the known by using recuperative heat exchanger installed between the exhaust air duct of poultry house and heat pump evaporator and the heat curtain installed on the air duct after the evaporator. The air coming into the poultry house after the regenerative heat exchanger is supplied to the heat pump gas cooler. The heat pump produces heat of the required parameters of the input air and water for watering of poultry, space heating, etc. Heat pump compressor is driven by gas engine (GPA), by natural gas or biogas. The part of the gas-piston engine heat is used for adjusting the optimal heat pump mode and for regeneration of the absorbent in an evaporative cooler. The proposed technical solution of the above scheme provides a higher COP of the heat pump. Installing of heat curtain does not require the use of non-freezing solution to prevent icing of the air outlet of heat pump evaporator. The latter allows producing, besides electric power and heat, still cold (with the use off the adsorption-refrigerating machine) and provide drying air inlet evaporative cooler (if necessary).

The analysis of scientific works shows that the development of technology is ahead of the level of development of energy management. There are no clear comparisons of the energy efficiency of electrical technologies and heat technologies. Objective indicators of energy efficiency in various technologies of dehydration of raw materials not developed yet. In that article assumed that objective results for comparing energy efficiency in the processing of raw materials is obtained by the basis of system analysis of the entire energy conversion chain from fuel to finished product. The purpose of the work is experimentally proving the objectivity of this hypothesis. To achieve this goal, it is proposing to use the indicator of the energy share of fuel in the finished product and the amount of moisture removed when burning 1 kg of fuel, which does not depend on fluctuations in energy prices, which can vary and differ for different countries. The most important result of the work is the comparison of these parameters with the data for innovative equipment samples developed by the authors. The significance of the results obtained is that the evaporating devices developed by the authors are not inferior in efficiency to traditional ones, and make it possible to obtain concentrates up to 90 ° brix. Thus, for fuels with an oil equivalent of 40 MJ per 1 kg, traditional dryers can remove no more than 3 kg of moisture, cryoconcentrators – 20 kg.

The article considers mathematical approach to environmental quality management to improve the ecological comfort of living for the population. The problem of environmental management is described using a multi-factor model of quality of the environment with the weight coefficients of the importance of its components: atmospheric air, acoustic impact, soil, water resources, and green spaces, accessibility of natural and recreational areas. The values of weight coefficients of importance of influencing factors for environmentally comfortable living are determined by the method of expert assessment. A multi-factor model is used for detailed assessment of the ecological quality of the urban environment. The proposed quantitative approach also allows to compare the environmental comfort of the different residential districts or to study the dynamics of environmental comfort of specific urban area. Much attention is paid to scientific and methodological principles of management and the formation of the concept of «environmental quality». The strategy of environmental management with ecological foundation of various practical solution is shown. The plan of measures on organization of optimal management of quality of the environment to improve comfort of living for the population of the residential microdistrict of Tiraspol is presented. Graphical scheme of the results of integral analysis of various environmental indicators and assessments for improving the comfort of the environment is given. Realization of environmental quality management of the urban areas on the basis of a multi-factor model contributes to the gradual change of dangerous ecological conditions of environmental factors, to increase a comfort of the territory taking into account the real preferences and needs of the population.

This article describes the results of a project called “Modeling Wind Power Plants. “The name of the project reflects the need to consider large wind farms as power plants as a result of increased penetration of wind energy into power systems. many places in the world. In order to optimally integrate the high penetration of wind energy into the system, large wind farms should be able to replace other power plants, that is, be able to participate in the management and stabilization of the power system. For example, if a large wind farm shuts off due to a power outage, the power system will suffer a severe power loss. The main result of the project is a proven model of a wind farm, which can be used to study and improve the characteristics of a wind farm power station, as well as a preliminary assessment of the quality of energy of a wind park based on modeling with a developed model and verified by measurements. The installation of wind turbines in power systems has developed rapidly over the past 20 years. В статье описываются результаты проекта «Моделирование ветряных электростанций». Название акцентировано на необходимость рассмотрения крупных ветряных электростанций в качестве электростанций в результате увеличения проникновения энергии ветра в энергосистемы. Чтобы оптимально интегрировать высокое проникновение энергии ветра в систему, крупные ветряные электростанции должны иметь возможность заменить другие электростанции, то есть иметь возможность участвовать в управлении и стабилизации энергосистемы. Например, если большая ветряная электростанция отключится из-за перебоев в подаче электроэнергии, энергосистема будет испытывать серьезные потери мощности. Основным результатом проекта является проверенная модель ветроэлектростанции, которую можно использовать для изучения и улучшения характеристик ветроэлектростанции, а также предварительной оценки качества энергии ветропарка на основе моделирования. Грозненский естественнонаучный бюллетень, Выпуск 4 (18) 2020, Pages 106-112

The purpose of this article is to develop a method and algorithm for the calculation of the steady-state mode and static characteristics of the squirrel-cage asynchronous motors that are supplied by a three-phase network with an asymmetrical voltage system. The aim is achieved by developing a method where the mathematical model of the motor takes into account the saturation of the magnetic core and the current displacement in the short-circuited rotor bars. Magnetization characteristics of the main magnetic flux and the leakage fluxes paths are used to account for the saturation. To account for the current displacement in the rotor winding the bars are divided into several layers throughout the height, resulting in a number of windings on the rotor with mutual inductive couplings. In the mathematical model, the processes in the asynchronous motor are described by a system of the nonlinear differential equations of electromagnetic equilibrium, composed in the fixed three-phase coordinate axes. The solution of this system in the steady-state mode is the periodic dependence of the currents, which are determined by solving the boundary problem. For this purpose, their algebraization is carried out by approximation of the periodic dependences at the nodes’ grid of the period of repeatability of the process by the third order splines. The solution of the problem is to determine the nodal values of coordinates on the period from the obtained nonlinear system of algebraic equations. For this purpose, the continuation method and iterative refinement by the Newton method were used. Calculation of the static characteristics was performed by the differential method.

The aim of the work is to increase biogas output and generation of electricity in biogas plants due to the joint fermentation of cattle manure with winemaking waste. To achieve this goal, the following tasks have been solved: the biogas yield from cattle manure with winemaking waste was determined during periodic loading of the digester; based on the obtained experimental data, a mathematical model was calibrated to estimate the biogas yield during fermentation of cattle manure with the addition of winemaking waste. Because of the studies, it had been found that when manure was fermented with part of the water replaced in the substrate 2% of the winemaking waste, the fermentation dynamics in the substrate are similar to the fermentation of pure cattle manure. Biogas obtained by fermentation of manure with the addition of 2%, 6.5% and 13% of wastewater from wine production instead of water in the first day of fermentation either did not burn at all or burned poorly. The addition of winemaking waste to a substrate based on manure in an amount of 13% allows increasing the maximum biogas yield by a third to 1,372 l/(hrkg dry organic matter). The significance of the research results lies in the fact that the use of winemaking waste as a substrate will allow a third increase in biogas output and power generation, and a reduction in the payback period of a 4,4 MW biogas plant using the green tariff to 6,5 years.

This article is devoted to the methods for increasing the operational efficiency of the singlestage and two-stage schemes of heat pump installations for heating systems, based on the energy saving principles. The major aim of the study is the analysis of methods for increasing the efficiency of alternative low-potential heat pump installations based on the subsoil waters, which correspond to the requirements of the energy saving technologies. To achieve the aim a comparative analysis of efficiency of different schemes of heat pump heating systems was performed for the consumers of the South-East of Europe. The rational schematic and constructive solutions and the system operational modes that ensure the increase in the efficiency of the alternative heating system for various climatic conditions were grounded. The main ways of increasing the efficiency of the low-potential heating systems using the heat pump units based on the subsoil waters were determined. Recommendations for the practical application of the alternative heating system solutions, depending on temperature of the outside air were developed. The significance of the obtained results consists in justification of conditions, which make it possible to use the single- and two-stage HPI schemes on the subsoil waters in the South-Eastern Europe. The most significant results are those recommending the increase in the operational efficiency of the heat pump systems on the subsoil waters for the heat supply for the consumers of the South-Eastern Europe. The analysis results can be used for designing the heating systems based on the heat pumps using the low-potential energy of the subsoil waters.

A significant number of domestic and industrial boilers are in operation in Ukraine. Nitrogen oxides are the most dangerous among all combustion products that pollute the atmosphere, therefore, one should take some measures for decreasing the formation of nitrogen oxides during combustion. The studies were carried out at the boilers of low power (100 kW) with a tubular radiator and an open end. The studies in the furnaces of industrial steam boilers having a tubular radiator with a closed end have not been done. The numerical study results of the gaseous fuel combustion processes in the furnace of a DE-10/14 steam water-tube boiler are presented. The fuel-air mixture is formed by premixing the 15% part of the air with a primary burner twist factor n=2.4 and a secondary burner twist factor n=1.6, and an air excess factor αв=10. As a result of the studies, the temperature and velocity distributions of gases in the combustion chamber, the density of heat flows on the screen tubular surfaces, and the concentrations of the combustion components were determined. Flue gas recirculation in the volume of 80-100% is provided, and the reversible movement of combustion products towards the combustion front provides a reduction in the concentration of nitrogen oxides up to 123-125 mg/m3 at the furnace outlet. Disadvantages are the following: the formation of stagnant zones near the end of the secondary radiator. The optimum diameter of the tubular radiator equals to two burners diameters and tubular radiator is located at a distance of one meter from the burner cutoff.