The article considers the concentration dependence of dust particles PM2.5 and PM10 on a curb stone on a number of influencing parameters. According to the data of field measurements, a quadratic regression equation was compiled, according to which the factors that have the greatest influence on the spread of fine dust near the roadway were determined. The results of mathematical processing of experimental data are presented in the form of a graph of the confidence area of the observed and predicted values constructed using the STATISTICA software product.

Keywords: PM10, PM2.5, fine dust, roadway, linear city, concentration dependence

The article discusses the method of thermal disinfection of hot water systems, its features and effectiveness, provides various schemes that ensure the processing of the system and the destruction of legionella bacteria.

Keywords: hot water supply, thermal disinfection, legionella, hot water schemes, centralized hot water systems

The article considers the directions and speeds of the air flow characteristic of the linear city of Volgograd. Weibull's law was tested for various wind speeds in various wind directions characteristic of Volgograd.

Keywords: climate, linear city, wind speed, wind direction, distribution law, distribution law, Weibull law, logarithmically normal law, impurity transport

The article deals with the distribution of fine dust in the atmospheric air of roadside areas of cities with a linear configuration, factors affecting its concentration in the roadside area.

Keywords: fine dust, roadside areas, road transport, wind speed, meteorological parameters

The main recommendations for the installation of a gas pollution detector in domestic premises are considered, an experiment is conducted using the Altair 4x gas analyzer, the purpose of which is to determine the concentration of the gas-air mixture at various points of the household relative gas source. The data obtained experimentally is analyzed, which results in a formula that allows you to determine the approximate concentration of the gas-air mixture, I only know the measurement time and height relative to the ceiling to the measurement point. Also, this formula allows us to note that when choosing the installation location of the gas pollution detector, attention should be paid to the distance from the ceiling to the installation point of the device, while the distance from the wall to the installation site of the device plays a less important role when a gas leak is detected by the device.

Keywords: gas pollution detector, gas-air mixture, gas concentration, emergency shutdown, lower concentration limit of flame propagation

The article analyzes the technical condition and reliability of heat supply networks. When using the calculation and assessment of the overall reliability of pipelines and sources of heat supply. Substantiates the requirements for the reconstruction of regular pipelines.

Keywords: heat supply, reliability of the heat supply system, hydraulic calculation, reliability coefficient, dilapidation of the heat supply network

The problem of choosing the most optimal gas supply scheme for rural settlements is considered, taking into account technical and economic criteria. For example x. Knyazhensky-1, Mikhailovsky district of the Volgograd region, several gas supply schemes are proposed. The feasibility study of the choice of one of the possible options is given. It was found that for rural settlements with an extended form, the most optimal is a scheme with two sources of gas supply and a reserving jumper between them.

Keywords: gas distribution network, gas reduction points, hydraulic regime, normalized pressure, cost, construction and installation works

The paper studies the problems of heat transfer intensification in shell-and-tube heat exchangers used in the heat supply of buildings. The solution to this problem is to use the circulation of the coolant flow in a pulsed mode, with different frequency pulsations. Based on experimental studies to determine the efficiency of a shell-and-tube water-to-water heat exchanger, a method has been proposed, in accordance with which it has been proved that the pulsed mode, compared to the stationary one, is the most effective in terms of key indicators, such as the heat transfer coefficient and thermal power.

Keywords: intensification, heat transfer, heat exchanger, coolant, fluctuations, efficiency, thermal power

The problem of removal of combustion products during the reconstruction of existing boiler houses is considered. The issue of determining pressure losses due to friction in steel and brick gas ducts when performing an aerodynamic calculation of gas ducts from gas-fired boilers is considered. Nomograms have been developed that make it possible to determine the specific pressure loss depending on the volume of flue gases and the diameter of the gas ducts.

Keywords: reconstruction, boiler units, aerodynamic calculation, friction pressure losses, gas ducts

The article discusses the history of the creation of heat generators. the main parameters of work and errors associated with the operation of this equipment. a brief description of such parameters as excess air coefficient, chemical underburning is given. on the example of an industrial enterprise in the city of Volzhsky, the relationship between the main indicators of heat generators and the adjustment of a gas burner is shown.

Keywords: energy saving, natural ventilation, the mechanical central zone ventilation system, the single apartment ventilation system, recovery, a planning solution for a building, energy saving, heat generator, boiler unit, gas burner, efficiency

This arcticle are devoted to the modernization of housing and communal system based on the technology of "Smart Grids". The methology of developing an assessment of the effectiveness of the project of the modernization of housing and communal services facilities using the technology of "Smart Grids" is given. It from the publication that the use of "Smart Grids" technology provides energy and economic efficiency in the development of the city's energy system

Keywords: Smart grids, "Smart City", centralized heat supply systems, individual heat supply, evaluation of the economic modernization project, key performance indicators

The article provides a solution to the problem of optimizing air ducts with a rectangular cross-section for ventilation and air conditioning systems. Based on the use of the methodology for optimizing air ducts according to the above costs, the optimal proportions of the sides of the rectangular cross-section of the duct are determined, depending on the amount of material costs for the duct device and the cost indicators of its operation. The obtained optimal aspect ratios of the cross sections of the ducts are universal and do not depend on the location of the duct relative to the system fan. These conditions allow, at the design stage of the ventilation system, to assess the degree of optimality of the decisions made on the choice of the dimensions of the cross-sections of the ducts and, if necessary, to make appropriate changes to the design solutions of the ventilation system. The obtained optimality conditions allow them to be included in the calculation programs of the air.

Keywords: fan, air heater, ventilation system, heating and ventilation system, energy, power, energy efficiency, energy conversion, mechanical power flow, thermodynamic system

This article discusses the advantages and perspective for the use of biogas in the conditions of the Republic of Crimea. The ecological and economic aspects of the use of biogas technologies at winemaking enterprises are touched upon. Describes the methods of using biogas at the winery "Massandra" in the Republic of Crimea. The calculation of the use of natural gas in the boiler house of a winery is made. A calculation was made for the use of biogas in a boiler house. It can be concluded that when using biogas in the boiler house of a winery, fuel needs are fully covered. The surplus of the remaining fuel is proposed to be used in a cogeneration plant to generate electricity.

Keywords: biogas, cogeneration plant, grape plant residue, recycling, interchangeability, granulate, natural gas, grapes, thermal energy, electricity, winery

This article discusses the features of the processes of heat and mass transfer, taking into account the formation of the contact surface during the interaction of air and water droplets sprayed in the working space of the spray chamber. The results of numerical modeling of heat and mass transfer processes are presented, which made it possible to establish the conditions of liquid atomization that ensure the most efficient flow of heat and moisture exchange processes in the working space of the spray chamber.

Keywords: air handling unit, spray chamber, heat and mass transfer, diffusion model, efficiency, droop parameters, calculation model, numerical simulation

The gas supply system of the industrial enterprise OAO Volgogradneftemash was created more than 50 years ago. Gas-using equipment is physically and technologically obsolete. The article proposes measures for the reconstruction of intershop gas pipelines and gas equipment. The substantiation of the choice of a new gas supply scheme for objects using a dead-end scheme and the installation of individual GRPSh for each consumer is given.

Keywords: reconstruction, gas supply system, production workshop,gas reduction point, material characteristics, enterprise, gas distribution network

An analysis of the accident rate on gas pipelines is given. Mathematical dependences of the volume of gas entering the atmosphere during the degassing of a gas pipeline section are given. Based on the existing nomogram for determining the gas compressibility factor for main gas pipelines, a nomogram for natural gas transported through gas distribution networks was constructed.

Keywords: gas pipelines, accident rate, degassing, gas bleeding, gas compressibility factor

The article is devoted to the issue of improving devices for cleaning gas station emissions from hydrocarbon vapors to improve the environmental safety of zones and territories of residential development. The largest part of the release of gasoline vapors entering the local aspiration systems is associated with the filling and emptying of fuel storage tanks at gas stations. It is known that emissions of benzene vapors belonging to the second hazard class have a significant problem in terms of exceeding the maximum permissible concentrations at the boundaries of the sanitary protection zones of gas stations and nearby residential buildings. Creation of new highly efficient technologies and devices for reducing the volume of pollutant emissions from gas filling complexes, while reducing operating costs by the amount of emissions and waste generated, developing reliable gas trapping devices of acceptable low material and energy consumption for gas station aspiration schemes is an urgent task. Another reason of elaborations’ needs of those gas trapping devices are reducing operating costs and environmental payments for emissions and waste. It was carried out environmental – economic research to verify justification to use absorption-type apparatuses within an absorbent mixture of sodium-magnesium salt’s solution (bischofite solution) and waste water of from a local purification device. It was allowed reducing emissions from sources of gas station aspiration schemes using capturing gasoline hydrocarbon vapors by mention above apparatus. It is essential reducing negative emissions’ impact of harmful substances and an additional amount of generated waste of gas stations. There are presented the results of calculating volume of the fees’ environmental damage, and economic efficiency of the use the proposed type of sorbent’ apparatus in this article also. The use of the proposed device in gas station aspiration schemes allows deceasing environmental payments for emissions including carbon taxes and fees and additional operating costs in terms of the use of consumables. The successful tests carried out have shown the reliable and efficient operation of the pilot plant with the proposed device at the gas station. The successful tests carried out have shown the reliable and efficient operation of the pilot plant set up with the proposed device that decreased environmental payments for emissions, waste and operating costs.

Keywords: gas station, gasoline, emission, atmosphere, concentration, hydrocarbons, aspiration, absorption, device, bischofite, water

In this article, the object of study is a research drying chamber of a convective type, in the design of which a condensing heat exchanger based on a vapor-compression heat pump is introduced. The drying process of lumber refers to energy-intensive technologies, since the share of drying in the cost of finished materials reaches 50% [1]. In the presented experimental study, comparative results of two operating modes of the experimental installation are presented: standard (soft mode) and recirculation mode with a condensate dryer. The obtained experimental drying curves show that the cost of electrical energy, taking into account the option with a condensing heat exchanger, decreased by 7.75% compared to the standard.

Keywords: drying modes, drying, heat pump unit, heat recovery unit, material balance, heat balance, moisture content, heat consumption, experimental setup

The article considers the improvement of the centralized heat supply system (SCT) from Saransk CHP-2 by optimizing the calculated quantitative and qualitative parameters of the hydraulic regime due to circuit solutions (optimization of the thermal circuits of the CTP and etc.), including the distribution of thermal loads; the use of devices (installations) providing the expansion of the temperature schedule of heat supply to the network. This event will allow: to create the technical possibility of technological connection of a promising thermal load; to reduce specific fuel consumption by increasing the share of combined power generation at Saransk TPP-2; will ensure an increase in the utilization rate of the installed thermal capacity of Saransk TPP-2 to 45-50%.

Keywords: temperature chart; hydraulic mode; combined production; central heating point

The results of verification of turbine and rotary gas meters used as measuring instruments in gas supply systems of industrial enterprises are presented. It was found that about 50% of calibrated meters exceed the requirements for the permissible values of the main relative error, as a rule, in the range of minimum gas flow rates. Ways to increase the service life of gas meters are proposed.

Keywords: gas flow metering, gas meter, verification, basic relative error, gas flow

The most common fittings in gas networks are investigated, such as bends with different angles of change in flow direction and equal tees. The dependences of the values of the coefficients of local resistance depending on the gas flow rate, diameter, angle of rotation and material of the product are determined. Recommendations are given for determining the coefficient of local resistance of the studied fittings.

Keywords: gas pipeline, hydraulic calculation, pressure loss, coefficient of local resistance, gas consumption, geometrical parameters

The article describes the design solution of a system for dedusting emissions into the atmospheric air using vortex inertial devices with counter-swirling flows (CSF) and a separator-concentrator. An approach to evaluating the efficiency of such a dust collection system is described. Analytical dependencies and a flowchart for calculating the efficiency of the system are presented.

Keywords: vortex inertial dust collector with counter swirled flows (CSF), separator-concentrator, dust collecting system, dust cleaning efficiency

In this work, an experimental model of pulsed regeneration of a sodium-cationite filter was developed. This model can work both with a stationary water flow and with a pulsed one. It is established that at a high pulse frequency, the water flow tends to a stationary one. It is found that at any frequency in a pulsed water flow, hydraulic losses will always be less than at a stationary one. At the same time, the smallest hydraulic losses are observed at a low pulse frequency of 1 Hz, and there is also a decrease in hydraulic losses in the range from 4 to 6 Hz.. It is established that at the same concentration of salt solution, the hardness of the treated water is lower in the pulsed mode than in the stationary mode. At the same time, the lowest stiffness is achieved at a low pulse frequency of 1 Hz. It is established that the time spent on regeneration at an equal inlet pressure will be longer with a pulsed water flow than with a stationary one at any frequency of pulsed regeneration.

Keywords: cationite, water treatment, sodium-cationite filter, stationary water flow, pulse water flow, frequency, salt solution, parallel-flow regeneration, hydraulic losses, pressure

In this work, a survey of the hot water supply system from the boiler house No. 2 of Energoservice LLC was carried out. The daily schedule of hot water released for sanitary needs is given. The existing scheme of the boiler burner on-off control system is considered. A method for stabilizing the hot water preparation process by increasing the burner shut-off settings at the hour of the highest water consumption is found and described, and their values are found experimentally. A scheme has been developed, assembled and tested that allows you to adjust the operating mode of boilers at a strictly specified time of day. The proposed measure allowed us to solve the problem of selling hot water to consumers of a given quality during the maximum water intake period. In addition, the reduction in the generation of thermal energy for heating hot water at night and on weekends allowed for a 13.87% reduction in natural gas consumption in 2020.

Keywords: hot water supply, fuel consumption, pumping station, circulation line, conditional fuel, mode, boiler unit

The paper provides an overview of the applications in central heating points (CHP) of technologies and equipment to improve energy efficiency and quality of heat supply from district heating systems. The main equipment and characteristics of the hot water supply system taken as an example of the central heating station "MGU" are given. Described is the method of choosing the heating circuit of the central heating station from the ratio of the maximum loads of hot water supply and heating. For the adopted example of a central heating station, based on the above characteristics, the main indicator of energy efficiency is the specific consumption of electrical energy for the transport of thermal energy. Factors that have the greatest impact on this indicator: coefficient of uneven consumption of "hot water"; quality of regulation of hot water supplied to the hot water supply network; precise control of the productivity of the boosting and circulation pumping stations. The standard total power of the pump drives has been determined to be 13.58 kW and the range of actual power is from 10.79 kW to 22.04 kW.To reduce the influence of factors in the control scheme, it is proposed to use flow (pressure) regulators to maintain a constant direct-acting pressure drop. Use the pressure (pressure difference) of hot water discharged to the DHW system and returned from the system as balancing forces for this regulator. The parameters of hot water of rational modes of operation of the hot water supply system from the central heating station "MGU" were determined: temperature of hot water at the outlet of the heat exchange equipment 75 ° С; hot water pressure at the outlet of the heat exchange equipment 45 m; hot water pressure at the inlet of the circulation pump 25 m. The implementation of the proposed option without the inertial control scheme for the temperature of "hot water" and the developed rational modes of operation of the hot water supply system, according to the assessment of efficiency indicators, will reduce the specific consumption of electrical energy in the central heating station by 28.4% from 0.631 kW * h / m3 to 0.452 kW * h / m3.

Keywords: central heating station, hydraulic mode, flow regulator, pump characteristic