RENEWABLE ENERGY INTEGRATION FOR HOT WATER SUPPLY AND HEATING OF BUILDINGS

Solar energy is widely used in solar systems, where economy and ecology are combined. Namely, this represents an important moment in the era of depletion of energy resources. The use of solar energy is a promising economical item for all countries of the world, meeting their interests also in terms of energy independence, thanks to which it is confidently gaining a stable position in the global energy sector. The cost of heat obtained through the use of solar installations largely depends on the radiation and climatic conditions of the area where the solar installation is used. The climatic conditions of our country, especially the south, make it possible to use the energy of the Sun to cover a significant part of the need for heat. A decrease in the reserves of fossil fuel and its rise in price have led to the development of optimal technical solutions, efficiency and economic feasibility of using solar installations. And today this is no longer an idle curiosity, but a conscious desire of homeowners to save not only their financial budget, but also health, which is possible only with the use of alternative energy sources, such as: double-circuit solar installations, geothermal heat pumps (HP), wind power generators. The problem is especially acute in the heat supply of housing and communal services (HCS), where the cost of fuel for heat production is several times higher than the cost of electricity. The main disadvantages of centralized heat supply sources are low energy, economic and environmental efficiency. And high transport tariffs for the delivery of energy carriers and frequent accidents on heating mains exacerbate the negative factors inherent in traditional district heating. One of the most effective energy-saving methods that make it possible to save fossil fuel, reduce environmental pollution, and meet the needs of consumers in process heat is the use of heat pump technologies for heat production.

OBTAINING DIESEL FUEL WITH IMPROVED PROPERTIES

It is known that one of the ways to increase the level of operational properties of diesel fuels is the injection of special components – additives – into their composition. Today this way is a quite rational and economically feasible for Ukraine, especially in the absence of high-quality oil raw materials for the production of fuels, which in turn leads to a significant dependence on imports. The range of additives used in diesel fuels is very diverse, which makes it difficult to select a balanced package, especially considering their effectiveness and compatibility with each other. This procedure can be a bit simplified by adding poly-functional additives to diesel fuel, the use of which is devoted to a lot of periodical literature. Based on the relevance of the direction of scientific research related to improving the properties of diesel fuel, which is produced at the enterprises of the oil refining industry in Ukraine, we proposed to use a substance belonging to the class of aromatic diazocompounds and having polyfunctional properties in the composition of diesel fuels. Thus, this additive was added to a straight-run diesel fraction (240–350 °C) in an amount of up to 1.0%, followed by a study of the properties of the resulting mixture. Studies have shown that the additive significantly improves low-temperature properties (by -10 °C), contributes to an increase in fuel density and viscosity, and additionally gives diesel fuel a stable color (from yellow to orange). Consequently, it can be used in the composition of commercial diesel fuels with improved performance properties.

MATHEMATICAL MODELING OF THERMAL EFFICIENCY OF BUILDING EN-VELOPE OF MULTI-STOREY BUILDINGS WITH ACCOUNT OF INDIVIDUAL INSULATION

At present, the problem of general thermal modernization of building envelopes is given much attention both at the level of scientists and consumers. This is one of the effective ways to reduce natural gas consumption, reduce the negative impact on the environment, maintain and improve comfortable indoor conditions. Over the last decade, the population has rapidly begun to insulate their homes in order to raise the indoor air temperature to a comfortable level in the multi-storey residential sector. Due to insufficient attention of the authorities in the housing and communal sector, the lack of scientific research and widespread public awareness, there is a massive thermal insulation of building by residents of multi-store buildings within their own apartments. But the study of thermal processes that occur in individual thermal insulation of enclosing structures is currently not fully completed. Therefore, in the context of significant increases in gas and electricity prices, this problem is relevant. In the study was carried out mathematical modeling of a fragment of a partially insulated wall of an enclosing structure with determination of heat flux by solving a three-dimensional differential equation of thermal conductivity with boundary conditions of II, III and IV kind and distribution of characteristics of building structures and insulation. These results can be used in the analysis of the efficiency of insulation of the building taking into account the fragmentary insulation and of comparison with systemic thermal modernization. As a result of modeling, the three-dimensional temperature fields of wall surfaces, are determined, there are additional heat fluxes (thermal bridges), which are not considered in the simplified one-dimensional calculation. In one-dimensional calculation, the heat flux from the wall is reduced by 2.43 times during insulation. Taking into account the total heat flow from the side surfaces near the window (thermal bridges) and system insulation - by 1.75 times. With fragmentary insulation and considering the total heat flux from the side surfaces near the window - by 1.6 times. The next stage of calculations is the determination of the actual air temperatures in the premises of a multi-storey building considering the actual condition of enclosing structures and heating systems, heaters, mode parameters of the coolant and outdoor air parameters. The methods and means of this analysis can take into account the final data of heat loss adjustment after the mathematical modeling presented in this paper. In consequence, the results will be taken into account in the projects of thermal modernization of buildings, reconstruction of heating systems, rational placement of sources, selection of equipment and regulation of devices.

SURFACE WATER QUALITY IN KHARKIV RECREATIONAL AREAS: 2006-2020

The aim of the paper is to assess dynamics of water quality in four main recreational areas in Kharkiv and to develop recommendations for water quality improvement. Methods. Field and laboratory methods and analytical data processing. Results. The paper presents analysis of dynamics in water quality for four main recreational areas located in Kharkiv: Zhuravlevskiy Hydropark, Oleksiivskiy Lugopark, Udyanskiy Hydropark and Osnovyanske Lake. Period of study: 2006-2020, time: May-June and August-September. Average data are presented. Samples were analysed at certified Laboratory of Analytical Chemical Research of the Karazin Institute of Environmental Sciences. Laboratory data were compared with national UA standards and European ones. Conclusions were made for the following key parameters: dissolved oxygen and BOD5, total mineralization, biogenic substances content, oil products and surfactants, toxic heavy metals content. There is no specific dynamics on the pollution level. Conclusions. The following recommendations for improvement of water quality were developed: (i) to preform regular monitoring of water quality; (ii) to introduce regular and systematic control by one local authority; (iii) to improve infrastructure of recreational areas; (iv) to introduce regular cleaning of the recreational areas; (v) to install bio-WC; (vi) to install additional waste containers (preferably with separate waste collection); (vii) plant trees for better isolation from highways; (viii) to improve level of water treatment on WWTP; (ix) to create nature protected areas along rivers

TECHNOLOGICAL ASPECTS OF APPLICATION OF THE PHYTOSORBENT WITH NANOTUBES IN THE PROCESS OF ADSORPTIVE OIL PURIFICATION

In the present article importance of adsorptive purification of vegetable oils is shown as the most responsible technological stage. Insufficiency of scientific developments in the scope of domestic sorbents in Ukraine is pointed out. The phytosorbent with nanotubes from sunflower peel improving some quality parameters of non-refined sunflower and soybean oils to standard values for refined oils has been offered. Some literature data on the main characteristics of a number of sorption materials (carbonaceous, natural, fibrous, and sorbents obtained from agricultural waste - Corylus avellana Lambert nuts) as a result of heat treatment are analyzed. The main sorption properties are considered; dignity; limitations. The effect of temperature on the productivity of pyrolysis of plant raw materials and the properties of the resulting carbonizates in the temperature range 150-600 °C was investigated. The duration of exposure of materials at the final temperature of the process in all experiments was the same and amounted to 1 h. Analysis of the experimental data allows us to conclude that temperature is the main factor affecting the process of carbonization of the initial plant material. Regardless of the pyrolysis atmosphere, the yield of the product from plant raw materials decreases with a significant increase in temperature. At present, the main raw material for the industrial production of adsorbents is in many studies organic substances - wood, fossil coal, peat, remnants of the processing of agricultural raw materials due to their low cost and large amount. Solving the problem of creating sorbents based on plant raw materials with the inclusion of hydrated fullerenes in their composition solved the problem of creating sorbents and environmental problems, since the waste did not always find a useful application. Concentration of water solution of hydrated C60, fast C60FWS, є molecular-coloidal systems and spherical fractal clusters, structural unit of which is micro-hydrophilic, high-hydrophilic supramolecular complex, molecules can be folded to fit into ) 24-hydration of fullerene C60 (C60HyFn). The hydrated cultivation is set in its own well-ordered, structurally heterogeneous watery middle, in which the directness and kinetics of chemical processes are seen in such, that it is necessary to be washed in order to clean.

ALGORITHMIC SUPPORT FOR DECISION-MAKING ON THE EFFICIENCY OF OPERATION OF ABSORPTION AND REFRIGERATION PLANTS OF AMMONIA PRODUCTION

The features of the hardware and technological design of the AM-1360 series ammonia synthesis units operating in Ukraine are established, the main of which is the use of heat-using ammonia-water absorption and refrigeration units in the secondary condensation complex. The analysis of the functioning of the absorption and refrigeration units has been carried out. A significant dependence of their efficiency on external disturbances, such as temperature and humidity of atmospheric air, has been established. This causes significant fluctuations in the cooling temperature of the circulating gas in the evaporators of absorption-refrigeration units, which significantly affects the efficiency of ammonia production in general. Based on the results of the analysis of the existing information system, implemented on the basis of the TDC-3000 microprocessor complex, recommendations for its improvement were developed, the presence of which makes it possible to abandon daily analyzes and carry out only control ones to check measuring instruments. Algorithmic support has been developed, implemented in the MATLAB package and tested according to the data of industrial operation of absorption and refrigeration units of the ammonia synthesis unit. This allows the operator, in real production conditions, to obtain operational information on the numerical indicators of the efficiency of operation of absorption and refrigeration units, which characterize their operation to the greatest extent (circulation rate, cooling capacity, circulating gas cooling temperature and thermal coefficient) and make a decision on the possibility of reducing the cooling temperature. of circulation gas in evaporators by changing the frequency of circulation of solutions The created algorithmic software in the MATLAB environment allows embedding a client module, the so-called OPC client. The latter provides technology for free programming of access to current data.

ASSESSMENT OF ECOLOGICAL AND GENETIC DIVERSITY OF THE GENUS VIGNA SAVI USING BIOTECHNOLOGICAL METHODS - ISSR MARKERS

The world's genetic resources of plants are the main source of improving crops for decades to come. The gene pool of plants has a hidden resource of new genes, or their combinations, including - selection-important features. The study of the potential of the plant gene pool with the main biological and economic characteristics allows to expand the genetic base of crops for the successful implementation of breeding programs in various areas. The genus Vigna has about 200 species that are grown in warm regions of the planet. The centers of origin of the species are in Africa, but mung beans, urd, azuki and rice beans are of Asian origin. The collection includes 20 specimens belonging to 7 species of the genus Vigna: V. aconitifolia (Jacq.) Marechal (willow aconitolista, mott) – 3 specimens, V. angularis (Willd.) Ohwi et Ohashi (adzuki) – 4, V. radiata (L.) R. Wilczek (mash) – 4, V. umbellata (Thunb.) Ohwi et Ohashi (vigna rice) – 4, V. unguiculata (L.) Walp. (Chinese) – 5. These are mainly local varieties, about 10 % are breeding varieties and 1% are forms that grow in nature. The multifaceted use of cultivated species of the genus Vigna contributed to their spread throughout the tropical, subtropical and temperate zones of the globe. They are economically important crops in many developing countries. Geographical analysis showed that most of the samples came from the areas of world agriculture and crop formation. most samples of V. radiata, V. mungo, V. aconitifolia, V. trilobata, V. umbellata were obtained from India and Pakistan, V. angularis – from East Asia and China, V. unguiculata – East Africa (Ethiopia, Kenya), V unguiculata – from China. However, the exact place of domestication of this culture has not been established, and in numerous sources of literature can be found different opinions of scientists on the origin of cowpea and the centers of its diversity. Recently, using the methods of molecular genetics (RAPD, AFLP and others) it was confirmed that the northern part of Africa is the center of origin of the cultured, because the wild types of West Africa are closer to cultural forms than the wild types of East and South Africa. It should be noted that the species of cowpea have a significant intraspecific polymorphism. The samples showed strong variability of morphological and economically valuable features. Such a wide range of variable variability is due to the places of cultivation of samples, different environmental conditions (plains, mountains, climate). According to the results of the evaluation of the DNA polymorphism of cowpea using molecular genetic markers, it was found that the species of cowpea involved in the study are characterized by a high level of DNA polymorphism, which averaged 78.6 %. 145 loci were identified, including 31 unique, specific to a particular sample, and 31 monomorphic, characteristic of all samples. Monomorphic loci are conserved regions of DNA that indicate the common origin of the species of cowpea involved in the work, and can be used as genus and species-specific markers. Unique loci indicate genetic divergence of the studied material and can serve as markers of certain samples. The average level of intrapopulation polymorphism of cowpea DNA (37.2–93.8 %, depending on the genotype) was established, which indicates the existence of significant variability in the studied samples of cowpea. It shows a high level of genetic divergence of cowpea species and testifies in favor of the polyphyletic theory of their origin.

FEATURES OF OBTAINING GELS BASED ON AGAR-AGAR FOR COSMETOLOGY AND MEDICINE WITH ANTIBACTERIAL PROPERTIES

In the modern world, special attention is paid to materials with controlled characteristics. In this aspect, polymers and materials based on them have a number of specific properties for effective use in medicine and cosmetology. Humic substances satisfy most of these features, so their use is very important. The study of the features of the processes of gelation in polymer systems such as agar-agar, which has rather universal properties, makes it possible to use it as a basis for gels and polymer carriers, as well as in the processes of obtaining medical and cosmetic materials with different properties, which can be important in solving a number of topical issues. In particular, these are lightweight and cheap to manufacture antiseptic gels, dressings on wounds with absorption and protective properties, all kinds of cosmetics. In the article, a study was carried out to study the processes of gelation and the features of the rheological properties of hydrogels based on agar-agar in order to obtain modern hydrogels with an antibacterial effect. It was found that the introduction of humic acids into the composition of polymer hydrogels slows down the processes of structure formation, which leads to a decrease in the viscosity of all the studied compositions. Also, a decrease in the melting temperature of hydrogel jellies with an increase in the content of humic acids in them indicates a reduced level of gelation, which also leads to an increase in the time of loss of stickiness of polymer hydrogels. It has been shown that humic acids in polymer hydrogels have high antibacterial activity and almost completely stop the processes of mold formation in them. It was found that the most effective from the point of view of obtaining hydrogels with an antibacterial effect are agar-agar compositions with a humic acid content of 15 %. Thus, cosmetic polymer hydrogels with an antibacterial effect have been developed, which can be used in the treatment of hands, face and other areas of the skin that are open and contact for humans to combat coronavirus bacteria.

USE OF ANALYSIS TECHNIQUE FOR IMMOBILIZED YEAST SACCHAROMYCES CEREVISIAE IN THE BIOTECHNOLOGICAL INDUSTRY

Article is devoted to the current state and problems of microbial cells immobilization and also prolonged storage of immobilized cells systems for the aims of biotechnological industry. In the experimental part immobilization conditions for the cells S. cerevisiae in alginate gel and vitality test, which had given high reproducibility of experimental results, were developed. Experimental results showed that viability of immobilized cells was higher than that of free yeast cells. It is possible that gel matrix has a protective effect on yeast cells during freezing. Comprehensive effect of cooling modes and preservation protective mediums, which contain sodium alginate, on viability of yeasts has been investigated. Advantage of yeast cells storage in immobilized state was shown experimentally. It was found that cooling mode and composition of preservation medium affect on the viability of S. cerevisiae cells during cryopreservation. In all freezing medium, both without protective components and with addition of a cryoprotective agent, the best results were obtained with cooling at a rate of 1°C/min. Viability indices in the samples were: 73.1 % – in distilled water; 90.8 % – in 1 % sodium alginate solution; 87.1 % – in 5 % DMSO solution and 86.1 % – in 1 % sodium alginate solution with the addition of 5 % DMSO. When cells were frozen in a 5 % DMSO solution and in a 1 % sodium alginate solution with the addition of 5 % DMSO, number of viable cells also decreased as cooling rate increased, but, probably, did not differ from the cell viability index in those samples that were frozen in 1 % sodium alginate solution. The highest results of viability for S. cerevisiae yeast cells were obtained during slow cooling for all cryoprotective mediums. For the first time, high cryoprotective properties of sodium alginate solution, were shown. Obtained results are enable to recommend the sodium alginate as a carrier for cryopreserved immobilized cells when using it in biotechnological processing for biologically active substances production.

NITRO CELLULOSE POWDER CHARGES OF LONG SERVICE LIFE: PROBLEMS AND THEIR POSSIBLE SOLUTIONS

One of the components of the problem of Ukraine's national security is the loading of warehouses with a variety of ammunition with an expired guaranteed storage period. The experience of storing ammunition shows that during long-term storage, propylene powder used in ammunition is capable of spontaneously undergoing various physical and chemical transformations, which negatively affects the ballistic characteristics of ammunition. The lack of ammunition production in Ukraine has led to the fact that ammunition is currently in operation, the storage time of which reaches 25-30 years or more. This article analyzes publications devoted to scientific research related to the problems of ballistic stability of propellants. A number of factors are presented that affect the physicochemical stability of powder charges during their long-term operation. The generalizing data on changes in the main ballistic characteristics of ammunition at different periods of their storage are presented. It is assumed that one of the ways to improve the ballistic and energy characteristics of ammunition with long service lives can be the regeneration of nitrocellulose powder charges. It is shown that at present there are no methods for the regeneration of propellant charges of long service life. However, there are encouraging data on the treatment of propellants with hydrogen peroxide, on the basis of which a technology can be developed for the complete or partial restoration of the ballistic and energy characteristics of the propellant charge. It is presented that the predictive assessment of changes in the characteristics of ammunition with long service lives does not correspond to their real indicators. It has been determined that the problem of nitrocellulose propellants of long service life is complex and, on the basis of its solution, theoretical and methodological foundations of the regeneration of nitrocellulose propellant charges can be developed to homologate the ballistic and energy characteristics of ammunition.