Alternative Energy is a scientific journal that publishes scientific achievements, innovative developments and research results in the field of alternative energy, as well as scientific and analytical articles and short reports. It is also planned to publish a special issue containing materials from international congresses, symposiums and conferences held within the scope of the journal.
NALYSIS OF MODERN DEVELOPMENTS IN SOLAR WATER DESALINATORS
Abstract. Introduction. This review explores the evolution and current trends in the publication of research on solar water desalination devices within the Scopus database. As global water scarcity intensifies, innovative solutions like solar water desalination have garnered increasing attention, prompting a substantial body of research aimed at enhancing the efficiency and accessibility of these technologies. The review analyses articles published over the last two decades to identify key developments, thematic shifts, and the geographic distribution of research efforts. Our findings reveal a significant increase in publication volume, reflecting growing academic and industrial interest in solar desalination technologies. This surge is largely driven by advancements in material science, thermal processes, and photovoltaic-powered desalination systems, which have progressively overcome earlier limitations related to energy consumption and cost efficiency. Additionally, the review highlights the contributions from leading countries in this field and discusses the integration of emerging technologies such as nanotechnology and artificial intelligence in optimizing desalination processes. This manuscript aims to provide a comprehensive overview of the landscape of solar water desalination research, offering insights into its developmental trajectory and projecting future research directions. Method. A thorough analysis of papers on solar water desalination systems indexed in the Scopus database was carried out using a methodical methodology. The process is divided into four main phases: data extraction, data collecting, screening and selection, and analysis. This methodical technique guarantees the correctness and dependability of the review findings. Results. 1,003 publications overall from the examination of solar water desalination research that was published in the Scopus database. The survey reveals a notable concentration of research effort in China, which accounts for more than half of the papers, with the United States, India, and China following. Articles make up the majority of the document categories linked with this subject (76.4%), indicating a significant emphasis on recent research findings. Conclusion. An examination of solar water desalination papers from the Scopus database shows a notable increase in research production over time, culminating in the last few years. A notable rise in publications—a total of 1,003 recorded papers—reflects this spike. The bulk of these articles originated in China, suggesting a substantial concentration of research activity in this area. In line with this, representation of the different forms of documentation reveals that articles make up the majority (76.4%), indicating a vibrant academic community. Reviews and conference papers also make significant contributions to the conversation around solar water desalination.
INNOVATIVE SOLUTIONS, TECHNOLOGIES AND DEVICES IN THE FIELD OF ALTERNATIVE ENERGY SOURCES
ASSESSMENT OF THERMAL ENERGY PERFORMANCE OF SWIMMING POOLS
Abstract. Introduction. This research work evaluates the results of a study of fuel and energy costs and thermal energy indicators of a heating system for an indoor swimming pool measuring 16x9 m in the city of Karshi. Methods and materials. In the course of research, taking into account the heat loss of the pool, an equation for the heat balance of the pool was developed and analyzed to ensure the required temperature regime.. Results. Based on the results of the experiment, it was established that the total heat loss of the pool was 11.87 kW. It is calculated that 7.44 kW of the greatest heat loss is due to the evaporation of water from the pool, 0.45 kW of the least heat loss is due to radiation heat loss from the pool. Conclusion. Based on the results of the experiment, the thermal energy performance of an existing swimming pool in the conditions of the city of Karshi was assessed. An existing heating system was proposed to improve the energy efficiency of this pool.
Nuriddin Elmurodov Nuriddin Sayitmurodovich
HEATING AND COOLING SUPPLY OF PUBLIC BUILDINGS BASED ON RENEWABLE ENERGY SOURCES AND HEAT PUMPS
Abstract. Introduction. Heat pumps are among the most efficient devices used for heating and cooling buildings. However, the main problem with heat pumps is the significant deviation of the external ambient temperature, during both summer and winter, from the optimal temperature required for the effective operation of the heat pump. Additionally, due to the high number of consumers during this period, the voltage in electrical networks drops, necessitating the use of expensive rectifiers. Methods and materials. To address the aforementioned issues, groundwater can be utilized, as its temperature is close to the optimal conditions for heat pumps, positively affecting their efficiency. Furthermore, photovoltaic and wind power stations can be installed to maintain voltage at nominal levels and generate energy. Results. Based on preliminary calculations, it can be stated that using this method increases the energy efficiency of heat pumps by 30%. Moreover, since several renewable energy sources are employed in the proposed scheme, it also enhances the efficiency and reliability of the specified system. It is also worth noting the short payback period, making it a promising approach. Conclusions. By applying the methods outlined below, it is possible to reduce the load on energy systems, increase the efficiency of heat pumps, and address water supply issues in certain areas.
ANALYSIS OF THE DEPENDENCE OF HEAT PUMP EFFICIENCY ON HEATER AND COOLER TEMPERATURES
Abstract. Introduction. Heat pumps are currently gaining significant attention on the international stage; however, their efficiency is often sensitive to the temperatures of heat sources (heaters). Therefore, without a thorough analysis of the climatic conditions of a specific region and its heat sources, it is challenging to select optimal heat pumps or accurately assess their efficiency. The temperature of certain heat sources, such as groundwater, is largely unaffected by external environmental conditions. This circumstance makes the use of groundwater a promising solution to several emerging challenges. Methods and Materials. This article examines the method for calculating the coefficient of performance (COP) of heat pump compressors based on the temperatures of the condenser and evaporator under a set thermal load. The effectiveness of heat pumps using air and groundwater as heat sources is also evaluated using the example of the city of Karshi. Results. Based on the presented formulas and real data on compressors, it was confirmed that one of the key factors affecting heat pump efficiency is the temperature difference between the heater and cooler. In this regard, it is suggested to utilize groundwater to reduce this difference. Conclusion. The application of groundwater as a heater or cooler has yielded very positive results. For example, during the summer period in the city of Karshi, the efficiency of the heat pump increased by at least two times, while in winter, it improved by at least 1.5 times.
Abstract. Introduction. The main criterion for determining the effectiveness of materials for hydrogen absorbers is the approach that materials for storing hydrogen must satisfy a number of simple properties - retain it in large quantities at room temperature, quickly release it at not too high temperatures, and not collapse. However, a material that fully meets the needs has not yet been developed. The search for new materials and various proposed solutions to the problem have been highlighted in a number of recent review articles. Therefore, the development of a hydrogen absorber based on an inexpensive porous material of a zeolite composition is relevant. Methods and materials. There are various ways to solve this problem, one of the most important of which is the use of the burn-out additive method and polyvinyl chlorine (PVC). The use of PVC is the most economical and affordable method for producing porous ceramics of a given composition. The studies used organic additives - rice husk and PVC. Results. The obtained materials of aluminosilicate composition with a specific surface area of ​​2500 cm2/g can be used as hydrogen absorbers with an aspect number from 3 wt.% to 13 wt.% in the temperature range of 100°C to 190°C. Conclusion. The created absorber based on porous ceramics of a zeolite composition is highly efficient.
COMPUTER MODELING OF MICRO-HYDROELECTRIC PLANT IN MATLAB/SIMULINK SYSTEM
Abstract: Introduction. As a result of the development of economic sectors in our republic, the increase in the standard of living, and the growth of the population, the demand for energy is rising. This situation greatly affects the development of the social and economic spheres, including the level of electricity supply to the agricultural sector of the country. One of the main solutions to mitigate these effects is the development and improvement of the efficiency of energy devices operating on renewable energy sources, particularly small-capacity hydroelectric plants. Methods and Materials. The article presents a 3 kW dual-rotor hydropower device adapted to water flows coming out of pump units used in agriculture, modeled using the Matlab/Simulink software package. Results. According to theoretical and experimental studies, the geometric dimensions of the guide apparatus were determined as follows: outer diameter 1 m, inner diameter 0.5 m, the number of guide vanes 16, the installation angle of the guide vanes β = -17.50, the blade diameter 0.5 m, hub diameter 0.2 m, the number of blades 6, the optimal installation angle of the blades 202.50, and the maximum water consumption rate is 0.24 m³/s. The nominal capacity of the micro-hydroelectric power station was determined to be 3 kW. Conclusion. According to the analysis of the technical and economic indicators of the device, as a result of the practical application of the developed 3 kW vertical axis micro-hydroelectric power station, it is possible to generate an average of 19,500 kWh of electricity per year, save 14.53 tons of conventional fuel, and prevent the release of more than 28.5 tons of carbon dioxide (CO2) into the atmosphere. The economic efficiency of this micro-hydroelectric power station was evaluated using the “Net Present Value” (NPV) method, with the net present value amounting to 5,500 USD, the static payback period being 1.56 years, and the dynamic payback period being 2.78 years.
counter-rotating double-rotor axial flux permanent magnet generator
DESCRIPTION OF EXPERIMENTAL RESEARCH OF A BIOGAS PLANT WITH DOSE
Abstract: this article presents information about the effective design of a multifunctional biogas device operating on the basis of requirements for the fermentation of agricultural organic waste under anaerobic conditions. Here are the results of theoretical and practical studies on the provision of a biogas device with a reactor volume of 30 m3, equipment for the normalization of organic waste and the study of its effect on the efficiency of the device. It is claimed that positive efficiency has been achieved, especially if mathematical regression calculations are followed when rationing waste. Method and materials: Experiment - when conducting experiments in the development device, we used generally accepted methods for conducting experiments in devices for anaerobic treatment of organic waste [8,9]. Results: The composition of the biogas obtained from the experimental bioreactor was sent to the branch of Uzbekneftegaz JSC Neftgazsledovanie, located in the Khorezm region, for testing in accordance with the requirements for experimental sampling [10]. Conclusion: Mixing number, mixing speed and mixing duration were taken as the main parameters of a biogas plant in the stepwise processing of organic waste, and the design of experiments method was used to determine their values.
EFFICIENCY OF THE INDIRECT TYPE SOLAR DRYING PLANT
Abstract. Introduction. Uzbekistan is the main producer of dried fruits adapted to its natural and climatic conditions. The use of solar-powered drying devices for drying fruits and vegetables is an important factor in reducing their cost. Methods and Materials. The article proposes a method for drying fruits and vegetables based on solar energy. The energy efficiency of the proposed solar collector for heating air was calculated using heat engineering methods. Results. The article describes the design features of the drying cabinet of the solar drying unit. To ensure natural and gradient convection and use the mechanism for heating the air of the greenhouse, an air heater is installed on the upper part of the thermal solar collector. The mixed arrangement of pallets installed at levels ensures a uniform flow of heated air around agricultural products on the pallets and promotes their turbulence along the height of the drying cabinet. Experimental data on the temperature of the heated air in the upper part of the air heater and on the pallets of the drying cabinet are presented. Conclusion. A solar drying plant for drying fruits and vegetables based on solar energy with an energy efficiency of 75-85% is proposed.
ASSESSMENT OF THE TECHNICAL AND ECONOMIC EFFICIENCY OF AUTONOMOUS SOLAR GREENHOUSES WITH EVEN-SPAN STRUCTURES
Annotation. Introduction. The assessment of the possibilities of using alternative energy sources in the energy supply of autonomous greenhouses, greenhouse development trends and the use of a combined solar-heat pump, which allows to increase energy efficiency and ensure the continuity of greenhouse operation in changing climatic conditions, is of great importance in the world and Uzbekistan. Methods and materials. A technological scheme of a combined power plant is proposed. The dynamics of temperature changes in the Kashkadarya regions was obtained on the basis of GIS technologies. The “net discount” method was used to assess the economic efficiency of autonomous solar cookers with two inclined structures. Results. Due to the use of heat pumps in greenhouses with a useful area of 50 m2 located in the Kashkadarya region, 127.6 million Soums and the device payback period is estimated at 5 years. At the same time, the economic profitability was about 20.79% per year. Conclusion. With the help of the proposed combined power plant, Autonomous greenhouses are provided with uninterrupted heat and electricity, in addition, agricultural products are drained. It is also based on the fact that solar photovoltaic devices can increase energy efficiency by 20-30% by removing dust and protecting against overheating in changing climatic conditions.
BASICS OF DESIGN AND MODELING OF 0.5 MW DETANDER-GENERATOR UNIT USING ANSYS CFX SOFTWARE
Abstract. Introduction. The use of expander-generator units in compression compressor stations is a promising way of increasing their economic efficiency. In the article, the calculation of the flow part of the turboexpander device, which is part of the expander-generator device used in compression compressor stations for supplying fuel gas to thermal power centers and stations with steam and gas turbine devices, was performed. Method and materials. Using the ANSYS CFX software, profiling of the turboexpander blade device, computational and experimental studies and analysis of the obtained results were carried out. Results. Based on the analysis of research sources, a technological scheme for the preparation of fuel gas using the expander-generator device was designed, and a three-dimensional model of the device containing the main parts of the unit was developed. Conclusions. The authors developed the concept of using a single-stage expander-generator unit with a maximum power of N = 498 kW, gas flow G = 3.32 kg/s, initial pressure of 5 MPa, outlet pressure of 1.5 MPa, with a gas dynamic bearing and put it into practice. suggested use.
ENERGY SAVING TECHNOLOGIES AND INSTALLATIONS
STUDYING THE THERMAL-TECHNICAL REGIME OF THE OBTAINED ALTERNATIVE FUELS IN THE HELIOPYROLYSIS DEVICE
Annotation. Introduction. The article presents the results of a thermal-technological regime study of the pyrolysis process of sunflower plant waste in a parabolic solar concentrator heliopyrolysis device. An experimental parabolic solar concentrator heliopyrolysis device was created to investigate the heliopyrolysis process. In the process of thermally processing sunflower plant waste, the dependency of the resulting products on temperature and the material balance were studied in experiments. In experiments conducted with the device, the pyrolysis of 1 kg of sunflower plant waste loaded into the heliopyrolysis reactor resulted in the production of 63% biochar, 10% liquid, and 27% gaseous fuels. Methods and Materials. The material balance of biofuels separated from the biomass loaded into the parabolic solar concentrator heliopyrolysis reactor was carried out in laboratory conditions with an initial moisture content of 10% and a size of 6-8 mm. The studies were conducted on sunflower plant waste. Results. According to the experiments conducted, it was found that the total yield of pyrolysis products varies little within the temperature range of 350-400°C. Thus, the pyrolysis of 1 kg of sunflower plant waste loaded into the experiment resulted in the production of 63% biochar, 10% liquid, and 27% gaseous fuels. Conclusion. The developed parabolic solar concentrator heliopyrolysis device allows the use of solar heat to cover the energy needed for conducting cycles during daylight hours. Experimental studies carried out with the parabolic solar concentrator heliopyrolysis device revealed that it is possible to obtain solid, liquid, and gaseous fuel samples from the pyrolysis of sunflower plant waste.
RESEARCH OF THERMO-MECHANICAL PROPERTIES OF THERMO-STABLE POLYMER COMPOSITES BY THE VIKA METHOD
Abstract. Introduction. Since plastics do not have an exact melting point, it is necessary to study the softening temperature of the material as equivalent to the melting temperature. Therefore, the VIKA softening temperature is included as an equivalent value for the melting point. In this case, the VIKA softening temperature was introduced as an equivalent value for the melting point, taking into account the temperature penetrating the test sample heated to a depth of 1 mm at a constant speed under load by a standard indenter with a flat bottom surface. The method of determining softening temperature according to VIKA is regulated by GOST 15088, ISO 306, DIN 53460, ASTM D1525 standards. Research methods and materials. There are various ways to solve this problem, one of the most important of which is the VIKA softening temperature. Results. Based on PP, obtained in different proportions PP+ Kaolin: vermiculite: UNT; PE based on PE+ Kaolin: vermiculite: UNT; PE+ Kaolin: vermiculite: UNT binary systems were created Conclusions. The created binary composite system is economical and import substitute, since most of the reagents used in their composition are domestic raw material waste.
Бинар тизимлар; ВИКА юмшатиш ҳарорати; полиэтилен; каолин: вермикулит; полипроплен.
RESEARCH OF THE KINETICS OF THE PYROLYSIS PROCESS OF BIOMASS (SUNFLOWER WASTE)
Abstract. Introduction. This article studies the kinetics of the pyrolysis process of biomass of sunflower waste particles based on Comsol multiphysics software, which allows us to determine the rate of chemical reactions occurring during the decomposition of the material and identify the main factors affecting the speed and efficiency of pyrolysis. The resulting models describe temperature trends quite well. It was concluded that the pyrolysis process of biomass of sunflower waste particles occurred in the temperature range of 440-717 K. At a temperature of 440 K, the biomass began to lose mass, and the mass loss stopped at a temperature of 717 K. The kinetic parameters were calculated using the Kissinger method. The least squares method and correlation analysis were used to calculate kinetic and constant parameters. The results will be useful in the future to optimize the process and conditions of the biomass pyrolysis process. Methods and materials. For the analysis in this study, the biomass of sunflower waste was used, since this biomass has high thermal abilities and a high yield of bio-oil. The particle size was 0.02 m2, and the thermophysical properties of sunflower were used. The analysis was performed using Comsol Multiphysics software. Results. When modeling the pyrolysis process of sunflower waste biomass based on Comsol Multiphysics software, temperature sensors were installed on the surface of the biomass and in the center of the biomass to measure temperature changes. Data on temperature changes depending on time are obtained. The models obtained describe temperature trends quite well, especially the temperature in the center of the biomass. Conclusion. The kinetic parameters were calculated using the Kissinger method. The least squares method and correlation analysis were used to calculate kinetic and constant parameters. The results will be useful in the future to optimize the process conditions of the biomass pyrolysis process. In the Kissinger method, the kinetic parameters were the same for the entire pyrolysis process. The correlation coefficient between temperature and heating rate in the model is 0.86.
FEATURES OF NICKEL FERRITE SYNTHESIS IN A SOLAR FURNACE
Abstract. Introduction. The synthesis method plays an important role in obtaining a material with a given particle size, structure, microstructure and specific surface area, and phase stability. These parameters together determine certain properties. The main synthesis methods are solid-phase reactions, thermal decomposition, hydrothermal and solvothermal methods, co-precipitation, sol-gel and microwave processing. However, each method has its own advantages and disadvantages, and there is no optimal way to obtain high-quality ferrite materials from spinel. Therefore, the study of the structure and properties of nickel ferrite NiFe0O4, synthesized from a melt of a mixture of Fe2O3 + NiO in a solar furnace Methods and materials. The mixture was ground in an agate mortar with the addition of ethyl alcohol (10 wt.%) and molded into tablets with a diameter of 12 mm and a height of 15 mm. The tablets were placed on a melting table located on the focal spot of a circle shaped with a diameter of 30 mm of the solar furnace. The melt was cooled by pouring into water. Hardened castings were ground, molded, and sintered at 1100°C. Results. A single-phase material representing a cubic modification of nickel ferrite NiFe2O4 with a lattice parameter of 8.87 Å was obtained. The freshly synthesized material exhibited a soft magnetic character with parameters Hc=60 Oe, Ms=30 emu/g. While the material fired at 1100°C showed increased parameters Hc=80 Oe, Ms=50 emu/g. Conclusion. The material obtained by synthesis from a melt in a solar oven can be used in catalytic processes of hydrogen synthesis by reforming organic raw materials due to its structure and magnetic parameters.
Muhammad-Sultankhan Paizullakhanov Muhammad-Sultankhan
PROSPECTS FOR THE INTEGRATION OF PHOTOVOLTAIC THERMAL INSTALLATIONS IN THE SPHERE OF ENERGY SUPPLY TO CONSUMERS
Abstract. Introduction. With the help of solar power installations of various technologies, solar energy is converted into electric, thermal and other types of energy, it is possible to produce hot water and even provide heat and cooling supply to premises. At the same time, photovoltaic thermal installations (PVTI) can serve as the optimal solution for integration in the energy supply of consumers with electric energy and hot water supply. Methods and materials. There are two main advantages of the PVTI, firstly, the efficiency of the modules can be increased due to active cooling and secondly, the collection in combination of a photovoltaic module with a thermal battery allows the heat to be used to generate thermal energy, heated water. Results. Based on the results of the research, PVTI based on thin-film modules of cadmium telluride were developed. Due to cooling of the back side of the module, the PVTI allowed to reduce the temperature by 8.6-21.5%, increase electrical efficiency by 1.7-2.5%, power by 8-10.3%, simultaneously produce electricity and heated water for consumer household needs. Conclusion. The developed FETs of various design types have been tested in hot climatic conditions. These installations can be used for power supply of hot water supply to consumers of different categories with integration in buildings and individual houses.
Thin-film photovoltaic modules of cadmium telluride
photovoltaic thermal installation, power supply
MAGNETIC PROPERTIES OF SILICON DOPED WITH IMPURITY MANGANESE ATOMS
Abstract. Introduction. Studies of the magnetic properties of silicon samples doped with manganese impurity atoms in the low temperature region (T=30 K) revealed ferromagnetic properties that had the following parameters Ms=3.41·10-3 emu/cm-3 (saturated magnetization),Mr=4.24·10-4 emu/cm-3 (residual magnetization) and Hc=158 Oe (coercive force). The possibility of creating magnetic sensors and spintronic devices based on silicon samples diffusion-doped with impurity manganese atoms is shown. It has been shown that silicon samples doped with manganese impurity atoms can be considered as a new magnetic semiconductor material. Methods and materials. The magnetic properties of silicon samples doped with manganese impurity atoms were studied in a Quantum Design MPMS-3 SQUID VSM magnetometer at a temperature T = 30 K. The results of the study showed that at low temperatures T < Tcr (Tcr is the Curie temperature) in silicon samples with impurity nanoclusters manganese atoms exhibit ferromagnetic properties. Results. A study of the magnetic properties of p-Si <B, Mn> samples in the low temperature region T = 30 K showed that a ferromagnetic state appears. These studies showed that by diffusion of impurity manganese atoms into silicon, a new magnetically sensitive semiconductor material can be obtained. It has been established that the magnetic properties of the obtained samples depend on the charge and spin state of the impurity manganese atoms in the formed nanoclusters. Conclusion. The high concentration of highly charged nanoclusters of manganese impurity atoms (BMn4) formed and the ferromagnetic state observed in them at T = 30 K with parameters allows this material to be used to create new types of devices in spintronics.
RESULTS OF EXPERIMENTAL STUDY OF AIR TEMPERATURE CHANGES IN THE SOLAR AIR COLLECTOR OF THE DRYING CHAMBER
Abstract. Introduction. Nowadays, solar air collector drying chamber is widely used for drying agricultural products. The solar air collector is one of the main devices of solar dryers and serves to heat the air supplied to the dryer to the required temperature. This scientific work presents the results of an experimental study of air temperature changes in a solar air collector intended for a solar dryer. The results of studies conducted on a typical day in May-October of the year and their analysis are also presentedUsul va materiallar. Quyosh havo kollektorining harorat rejimi va issiqlik samaradorligini hisoblash quyidagi usul yordamida amalga oshirildi. quyosh havo kollektori yuzasiga tushgan umumiy radiatsiya, quyosh havo kollektoridagi havo tomonidan olingan foydali issiqlik va quyosh havo kollektoridan umumiy issiqlik yo'qotilishi bilan. Natijalar. Quyosh havo kollektorli va issiqlik nasosli qurilmalari asosida ishlaydigan kombinatsiyalashgan sovutish quritish kamerasi qurildi va ishga tushirildi, tajribani о‘tkazish metodtikasi ishlab chiqildi Xulosa. Kombinatsiyalashgan sovutish quritish kamerasi uchun absorberida tо‘siqlari mavjud bо‘lgan quyosh havo kollektorining tajriba qurilmasi tayyorlandi va tajriba sinovlari о‘tkazildi. quyosh havo kollektorida havo haroratini о‘zgarishini aniqlash bо‘yicha 2023 yilning may-sentabr oylarining xarakterli kunlarida о‘tkazilgan tajriba tadqiqotlarida tashqi havo harorati 19...40℃ bо‘lganda, quyosh havo kollektori yordamida о‘rtacha harorati 50...77℃ bо‘lgan issiq havo olish, shuningdek, quyosh radiatsiyasi intensivligi 5,8...7,86 kVt/m2 bо‘lganda, foydali maydoni 2,52 m2 bо‘lgan quyosh havo kollektori yordamida 14,1...17,9 kVt·soat miqdorida foydali energiya olish mumkinligi aniqlandi.
STUDY OF ENERGY EFFICIENCY OF LOW-TEMPERATURE WATER-TO-WATER HEAT PUMP
Today, there is a growing trend towards the introduction of heat pumps in the heating system. Because low-grade heat can be used as a source in heat pumps, it is highly energy efficient. Therefore, it is important to calculate the efficiency of a heat pump using low-temperature heat sources and assess the feasibility of introducing a heat pump into the heating systems of the Karshi districts of Uzbekistan