The use of the main pollutant of the biosphere, fossil fuels, accounts for more than 90% of the world and has no realistic downward trends in the coming decades. The rapidly developing economies of China, India, Latin America and the African continent, where most of the world's population lives, cannot be limited in development due to the equality of people before God in favor of countries that already have a high level of industry and energy.

An urgent requirement of today is the creation of technologies that save limited resources of natural fuels (gas, coal, uranium, etc.), minimize the anthropogenic load on the biosphere and increase the efficiency of energy use for consumers. This paper examines a possible option for the joint use of all types of currently available energy technologies to create reliable energy and achieve a synergistic effect in reducing the environmental burden and minimizing fuel consumption.

This article is devoted to the study of the possibilities of assessing the indicators of the heating degree-day (HDD) and cooling degree-day (CDD) for the territory of the Republic of Uzbekistan using international meteorological databases such as NASA POWER and ERA5 in order to make adjustments to the energy building codes in force in the country when determining the load for the design of systems heat and cooling supply in buildings and structures.
The authors present the results of studies to determine the dynamics of changes in the heating and cooling degreeday indicators (HDD and CDD) on the territory of the Republic of Uzbekistan over the past 15 years (for the period 2005-2020) on the basis of international databases. It is shown that when using NASA POWER data to calculate HDD values on the territory of Uzbekistan, the error is from 7 to 14%, whereas when using ERA5 data, this number varies between 5-9% at different base temperatures.
It is also shown, that in the case of CDD calculation, it is impractical to use data from both databases, and the use of ground-based observations is recommended to solve this problem. At the same time, in the absence of meteorological stations in a certain region (according to the map of their location on the territory of the country), in the future it is necessary to install additional ones suitable for conducting scientific research, according to the known methodology.
The paper also presents a project of a digital HDD map for the territory of Uzbekistan, which is a scientific and technical product of a strategic nature in terms of building codes and regulations in the republic in order to plan heat and cooling systems for buildings and structures with the least errors.
It is noted, that the inclusion of additions and changes to existing energy building codes and regulations, as well as the proposed HDD map project for the country, being a significant step in the development of energy policy in the republic, will be useful to international investors in the preparation and planning of related projects.

The article deals with the issue of operation of heat exchangers in the mode without scaling when using geothermal waters in the heating and hot water supply system. The possibility of simultaneous utilization of methane from water with the preservation of the equilibrium concentration of carbon dioxide in it is estimated. A technique is proposed for periodic dissolution of carbonate deposits in a heat exchanger, formed when carbon dioxide balance is disturbed in a solution of geothermal water. At the same time, a relationship has been established between the concentration of carbon dioxide in water and the time of dissolution of previously formed deposits of calcium carbonate in the heat exchanger. This makes it possible to evaluate the decrease in heat losses with a decrease in heat transfer coefficients in the heat exchanger during the dissolution process. A schematic solution is given for the integrated development of the energy of geothermal water sources, in which the protection of power equipment from carbonate deposits is carried out by the combustion products of utilized methane.

The relevance of the study is due to the transition to environmentally friendly and resource-saving energy according to the Decree of the President of the Russian Federation dated 07.07.2011 No. 899 (ed. Dated 12/16/2015) "On approval of priority directions for the development of science, technology and technology in the Russian Federation and the list of Critical technologies of the Russian Federation".
In this regard, this article is aimed at revealing the possibilities of using alternative fuels, improving technical and economic indicators and improving energy efficiency and environmental friendliness of biogas use. The main approach to the study of this problem is the use of biogas and methods of purification of biogas from ballast.

In this paper, the use of grape cakes as raw materials in the production of bioethanol, an alternative type of fuel, is considered. At the same time, the effect of the use of a multi-enzyme complex in the process of enzymatic hydrolysis was studied. It should be noted that the problem of increasing the efficiency of bioethanol production is solved, on the one hand, by increasing the concentration of monosaccharides that accumulate during enzymatic hydrolysis. Increasing the efficiency of the enzymatic hydrolysis process is key in obtaining second-generation biofuel products. Therefore, the cellulose obtained as a result of primary processing was affected by various combinations of enzyme preparations consisting of a multi-enzyme complex. The daily growth in demand for fuel energy, as well as a decrease in the amount of petroleum products on earth, require the use of alternative sources of raw materials in the industry, indepth analysis of their composition and processing based on environmentally friendly technologies. This article explores the exclusivity of the technology for producing second-generation bioethanol from renewable sources.

The article presents a comparative analysis of effectiveness of the approaches developed by the authors to ensuring a further development of nuclear energy industry as a pollution-free energy source. To solve this problem, several options for using environmentally friendly hydrogen fuel were considered to ensure a high installed power factor of NPPs and/or maneuverability of existing and planned double-loop NPPs with a water coolant. It is proposed to accumulate off-peak electricity by means of water electrolysis to obtain hydrogen and oxygen, which ensures the basic operation mode of NPP and provides a possibility to use hydrogen/oxygen to produce peak electricity. The given approach is compared with the basic scheme of marketable hydrogen and oxygen production including their additional purification. The economic feasibility is estimated with account for the effect from replacement of environmentally harmful plants based on gas turbine units, including the effect of preventing forced unloading of NPPs and various options to the target prices for nuclear and hydrocarbon fuel. As a result, the main technical and economic indicators of the proposed approaches were determined, including the cost and accumulated net present value. Based on the assessments made, it is shown that the options for providing NPPs with a basic electrical load based on the proposed approaches are efficient and competitive. Production of hydrogen and oxygen with a subsequent production of peak electricity, i.e. the use of a hydrogen power complex as an off-peak energy storage allows achieving the maximum economic effect. The provided estimates show the relevance and prospects for solving the problem of providing NPPs with a baseline electrical load under conditions of increasing their share in the energy grid based on the combination with a hydrogen power complex.

A thermal circuit was developed for the conversion of a cogeneration power plant to trigeneration with the production of hydrogen as a new product. The Severnaya CHPP-21 of St. Petersburg, which has 5 power units with a steam turbine T-100/120-130-3, was chosen as the object for switching to a trigeneration mode of operation.
The purpose of the work is to evaluate the effect of switching a cogeneration power plant to trigeneration production of electricity, heat and hydrogen, taking into account the characteristic operating modes of the main equipment of
a power plant.
Research methods include simulation modeling of the thermal scheme of the steam power plant in the United Cycle program, modeling of the process of steam reforming of methane in the Aspen HYSYS program, as well as thermodynamic analysis of heat recovery units.
A new thermal circuit of a trigeneration power plant with a methane steam reforming unit (MSRU) integrated into its structure was developed. An assessment of the influence of the MSRU on the characteristic modes of operation of a combined heat and power plant (CHP) was carried out. In winter mode with low heating loads, fuel savings in the combined production of electricity, heat and hydrogen amounted to 2.5%. The coefficient of fuel heat utilization increased from 78.61% to 80.63%. In the summer mode of operation of the station, the most profitable mode turned out to be the mode with the operation of only one power unit. Fuel economy when integrating a steam-reforming unit into the CHPP was 13.8%. The coefficient of fuel heat utilization increased from 62.26% to 72.25%.
The proposed research algorithm is applicable to thermal power plants of any type. The developed schematic thermal circuit of a plant with combined production of hydrogen, heat and electricity is applicable for implementation at most thermal power plants, which have a sufficient number of typical cogeneration steam turbine units.
The study shows that during off-peak times of electricity and heat supply, thermal power plants can be used to produce additional technological products.

The burning of agro-industrial and agricultural waste, or, as they are called by fire fighting specialists, agricultural waste, oddly enough, is associated with climate change, which is noticed not only by climate scientists, but also by ordinary citizens. The bioconversion of ordinary cane waste into processed sugars for the production of bioethanol is an urgent and dynamically developing area of research. The purpose of this work was to study two types of pretreatment with alkali and steam of waste cane. Pretreatment with alkali revealed superiority in relation to the rate of enzymatic hydrolysis and, as a consequence, an increase in the productivity of bi-ethanol. In a pretreatment medium with a 6% alkali solution in an autoclave, a high content of total reducing sugar was shown. Fermentation of cane hydrolysates with Saccharomyces cerevisiae Y-1693 contributing to the yield of the product in the amount of 17.5 g/l of bioethanol. The results of the conducted studies show that the biomass used is extremely relevant for the production of bioethanol. In this regard, the waste ordinary cane can be used for the production of second-generation bioethanol, and becomes a potential candidate for future production of bioethanol based on the results of the conducted research.

The paper discusses a version of a medium-temperature modular pyrolysis plant that can be used to derive all pyrolysis products – gas, oil, and carbon (soot) – from municipal solid waste (MSW).The yield of gas is 97∙10-3, oil – 257∙10-3, and carbon – 140.1∙10-3 kg/(kg MSW). Specific heating value per kg MSW is 1,904 kJ for gas, 11,334 kJ for oil, and 4,680 kJ for carbon. The products of MSW pyrolysis have been used at an existing thermal power plant (TPP) equipped with the boiler E-120-100 and condensing turbine K-25-90. The rate of MSW consumption with the steam turbine unit operating at its maximum capacity of 25 MW is 5.35 kg MSW per second. The thermal efficiency of the unit is 26%. Specific MSW consumption for electric generation is 0.773 kg/kWh (0.474 kgoe/kWh). Electricity production per 1 metric ton (MT) of recycled MSW is 1,289 kWh. The rate of MSW consumption to supply the diesel generator driving the drum of the pyrolysis plant with the capacity of 5.5 kW is 2.9 kg/h. Operation of the power plant at its full capacity of 25 MW would require 15 modular pyrolysis plants running simultaneously. A single pyrolysis unit and a low-power steam turbine (e.g., TG 0.75/6.3R13/2 KTZ) can be used for a mini-TPP with a capacity of 600 kW.

A cogeneration power plant based on a solid oxide fuel cell with an aluminum-hydrogen reactor in which hydrogen is obtained from aluminum and water in the presence of alkali is described. The efficiency of such a reactor is 43.7%. The fuel utilization rate at a power plant with an electric capacity of 10 kW is 42.3%. The electrical efficiency of the fuel cell is 77.2%, the proportion of hydrogen oxidized in the anode is 80.5%. The specific consumption of conventional fuel for the production of electric energy is 0.283 kg. t., and for the production of thermal energy 78.7 kg.t./ GJ.
Specific indicators are higher compared to similar indicators for cogeneration power plants running on hydrocarbon fuel, but less than in the Russian energy system – 0.33 kg cubic tons/ kWh.

The paper presents an analysis of the the radiotoxicity of the fission products of the cores of thermal (VVER, RBMK) and fast (FN) neutron reactors, a model of fuel elements with an inert matrix. It is shown that the exclusion of ²³⁸U from the fuel composition makes it possible to reduce the radioactivity of the fuel composition for thermal neutron reactors by three orders of magnitude; for fast neutron reactors by 1-2 orders of magnitude compared to traditional fuel compositions containing ²³⁸U.
Allows you to reduce the long-term radioactivity created by actinides by more than 2 orders of magnitude.

Russia's experience in the use of highly enriched fuel in research reactors (for example, IVV-2), Topaz nuclear power plant (90% ²³⁵U) confirms the results of the analysis to reduce the radioactivity of core and spent nuclear fuel.

 The paper considers the main methods that can be used to regulate the neutron spectrum in nuclear reactors. Their basic principles of operation, advantages and disadvantages are shown. 

 When the temperature of a material is changed, the substance will either expand or contract depending on the change, and this expansion or contraction will occur in all directions simultaneously. The objective of this research is to analyze the behavior of volume and pressure variations of gas chambers containing air with additional low boiling liquids such as (acetone, alcohol, and benzene) depending on the impact of changing the temperature.