The prospectі of wider implementation of more powerful wood biomass projects in Ukraine will lead to an increased demand of wood chips, and its increased production is expected from logging residues, which now are almost unused, as well as the continuation and possible expansion of its production from logwood. When organizing the production and supply chains of wood chips, the advanced methods of timber harvesting and the possibility of their adaptation in Ukraine should be considered, as well as to increase economic efficiency of supply, taking into account the need to save wood chips fuel properties during storage, which requires proven methods of reducing of moisture content and preventing the dry matter loss. International experience shows that production, storage and supply methods of wood chips directly affect its quality and fuel characteristics, and its efficient use as fuel must be ensured by appropriate technical solutions of boiler equipment.
{"title":"ANALYSIS OF INTERNATIONAL EXPERIENCE TO EXPAND PRODUCTION AND SUPPLY OF WOOD CHIPS IN UKRAINE","authors":"V. Kramar","doi":"10.31472/ttpe.3.2022.8","DOIUrl":"https://doi.org/10.31472/ttpe.3.2022.8","url":null,"abstract":"The prospectі of wider implementation of more powerful wood biomass projects in Ukraine will lead to an increased demand of wood chips, and its increased production is expected from logging residues, which now are almost unused, as well as the continuation and possible expansion of its production from logwood. When organizing the production and supply chains of wood chips, the advanced methods of timber harvesting and the possibility of their adaptation in Ukraine should be considered, as well as to increase economic efficiency of supply, taking into account the need to save wood chips fuel properties during storage, which requires proven methods of reducing of moisture content and preventing the dry matter loss. International experience shows that production, storage and supply methods of wood chips directly affect its quality and fuel characteristics, and its efficient use as fuel must be ensured by appropriate technical solutions of boiler equipment.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"660 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74755344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O.O. Zaitseva, S. Cherednychenko, Ye.M. Hryshchenko, O.I. Iatsiuta
Purpose The purpose of this article is to consider the features of calibration of single heat meters during operation. Results of operation Heat meters belong to the field of legally regulated metrology, as their measurement results are used in calculations between consumers and suppliers of heat for heating and hot water supply, so they are subject to periodic verification during operation and after repair. The so-called single heat meters have been widely used in the equipment of individual heat metering units for space heating. The peculiarity of single heat meters is that for them the error in measuring the amount of heat is normalized and experimentally determined without dividing it into the errors of the components. The physical quantities supplied to the heat meter inputs are reproduced тепло the heat carrier consumption and the heat carrier temperature. In this case, the water temperature in the flow unit corresponds to the ambient temperature, and the temperature in the thermostats to the temperatures in the supply and return flows. However, for heat meters based on ultrasonic method of washing the coolant flow with compensation of changes in the speed of ultrasound from the temperature of the coolant, this calibration technique cannot be applied due to a methodological error from replacing the variable speed of ultrasound with a constant value. To ensure the reliability of the verification results, a methodology was developed, according to which the verification is carried out in two stages. At the first stage, the error of the heat meter is determined when measuring the flow rate as the difference between the readings of the heat meter and the reference value of the flow rate reproduced by the spill unit. In this case, the temperature superheater of the heat meter is placed in a thermostat with a temperature equal to the temperature of the water in the pouring unit. This eliminates the methodological error from the temperature mismatch in the thermostat and in the pouring unit. In the second stage, the error of the heat meter is determined when measuring the temperature and calculating the amount of heat. In this case, the reference values in the thermostats and the readings of the heat cell when measuring the consumption of the heat carrier are taken as the reference values of the reproducible values. The total error of a single heat meter is defined as the sum of the errors obtained during the first and second stages of verification. Conclusion Calibration of heat meters during operation contributes to obtaining reliable results of measurements of the amount of heat consumed in the housing stock, and the development on the basis of these results of measures aimed at the rational use of energy resources.
{"title":"CONTROL OF METROLOGICAL CHARACTERISTICS OF HEAT METERS DURING OPERATION","authors":"O.O. Zaitseva, S. Cherednychenko, Ye.M. Hryshchenko, O.I. Iatsiuta","doi":"10.31472/ttpe.1.2022.11","DOIUrl":"https://doi.org/10.31472/ttpe.1.2022.11","url":null,"abstract":"Purpose \u0000The purpose of this article is to consider the features of calibration of single heat meters during operation. \u0000Results of operation \u0000Heat meters belong to the field of legally regulated metrology, as their measurement results are used in calculations between consumers and suppliers of heat for heating and hot water supply, so they are subject to periodic verification during operation and after repair. The so-called single heat meters have been widely used in the equipment of individual heat metering units for space heating. The peculiarity of single heat meters is that for them the error in measuring the amount of heat is normalized and experimentally determined without dividing it into the errors of the components. The physical quantities supplied to the heat meter inputs are reproduced тепло the heat carrier consumption and the heat carrier temperature. In this case, the water temperature in the flow unit corresponds to the ambient temperature, and the temperature in the thermostats to the temperatures in the supply and return flows. However, for heat meters based on ultrasonic method of washing the coolant flow with compensation of changes in the speed of ultrasound from the temperature of the coolant, this calibration technique cannot be applied due to a methodological error from replacing the variable speed of ultrasound with a constant value. To ensure the reliability of the verification results, a methodology was developed, according to which the verification is carried out in two stages. At the first stage, the error of the heat meter is determined when measuring the flow rate as the difference between the readings of the heat meter and the reference value of the flow rate reproduced by the spill unit. In this case, the temperature superheater of the heat meter is placed in a thermostat with a temperature equal to the temperature of the water in the pouring unit. This eliminates the methodological error from the temperature mismatch in the thermostat and in the pouring unit. In the second stage, the error of the heat meter is determined when measuring the temperature and calculating the amount of heat. In this case, the reference values in the thermostats and the readings of the heat cell when measuring the consumption of the heat carrier are taken as the reference values of the reproducible values. The total error of a single heat meter is defined as the sum of the errors obtained during the first and second stages of verification. \u0000Conclusion Calibration of heat meters during operation contributes to obtaining reliable results of measurements of the amount of heat consumed in the housing stock, and the development on the basis of these results of measures aimed at the rational use of energy resources.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84849599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Fialko, V. Prokopov, R. Navrodska, S. Shevchuk, A. Stepanova
The results of a complex of experimental studies of thermal and aerodynamic indicators of water-heating heat-recovery exchangers of dusty exhaust gases from glass-making furnaces are presented. The studies were carried out on an experimental installation located behind a glass-melting furnace, and in the process of start-up operations during the introduction into operation of modular-type water-heating heat exchangers (HWM) developed by IET NAS of Ukraine at various glass-producing enterprises. The studies were carried out using modern measuring equipment according to certified methods of the services of metrological adjustment of glass-making enterprises, with the participation of which the experiments were carried out. In the process of research, the heating capacity, average values of the heat transfer coefficients and aerodynamic resistance of heat exchange surfaces, which are assembled from of panel packages formed by pipes with membranes, under conditions of heat-recovery of dusty furnace gases, were determined. The dynamics of the formation of a layer of deposits of technological dust on the surface of the panels on the gas side and the contamination coefficient of surface were also subject to research. According to the data on the heat-recovery exchanger heating capacity, the rational period of its operation between cleaning the working surfaces was determined. The experimental parameters obtained were also compared with their calculated values, as well as with the data of other researchers. According to the results of the studies, it is shown that TVM heat exchangers when used in conditions of dusty furnace gases are characterized by high thermal efficiency due to the layout of the heat exchange surface from the packets of panels formed by pipes with membranes, and the possibility of cleaning these surfaces from deposits of technological dust with practical restoration of the initial indicators. Based on the data obtained, the duration of the cycles for cleaning membrane heating surfaces from dust deposits was determined: for furnaces for the production of glass packaging, this period was 10-14 days, and for furnaces for melting medical glass - 5-7 days.
{"title":"RESULTS OF EXPERIMENTAL STUDIES OF THE HEAT ENGINEERING CHARACTERISTICS OF INDUSTRIAL FURNACE WATER-HEATING HEAT RECOVERY UNITS","authors":"N. Fialko, V. Prokopov, R. Navrodska, S. Shevchuk, A. Stepanova","doi":"10.31472/ttpe.1.2022.10","DOIUrl":"https://doi.org/10.31472/ttpe.1.2022.10","url":null,"abstract":"The results of a complex of experimental studies of thermal and aerodynamic indicators of water-heating heat-recovery exchangers of dusty exhaust gases from glass-making furnaces are presented. The studies were carried out on an experimental installation located behind a glass-melting furnace, and in the process of start-up operations during the introduction into operation of modular-type water-heating heat exchangers (HWM) developed by IET NAS of Ukraine at various glass-producing enterprises. The studies were carried out using modern measuring equipment according to certified methods of the services of metrological adjustment of glass-making enterprises, with the participation of which the experiments were carried out. In the process of research, the heating capacity, average values of the heat transfer coefficients and aerodynamic resistance of heat exchange surfaces, which are assembled from of panel packages formed by pipes with membranes, under conditions of heat-recovery of dusty furnace gases, were determined. The dynamics of the formation of a layer of deposits of technological dust on the surface of the panels on the gas side and the contamination coefficient of surface were also subject to research. According to the data on the heat-recovery exchanger heating capacity, the rational period of its operation between cleaning the working surfaces was determined. The experimental parameters obtained were also compared with their calculated values, as well as with the data of other researchers. According to the results of the studies, it is shown that TVM heat exchangers when used in conditions of dusty furnace gases are characterized by high thermal efficiency due to the layout of the heat exchange surface from the packets of panels formed by pipes with membranes, and the possibility of cleaning these surfaces from deposits of technological dust with practical restoration of the initial indicators. Based on the data obtained, the duration of the cycles for cleaning membrane heating surfaces from dust deposits was determined: for furnaces for the production of glass packaging, this period was 10-14 days, and for furnaces for melting medical glass - 5-7 days.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"72 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76308170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Basok, B. Davydenko, V. Novikov, H. Koshlak, A. Pavlenko
Introduction. The purpose of these studies is to determine the effect of the filtration properties of soil as a porous medium on the performance of soil heat exchangers. Ground heat exchangers are important elements of heat pumps widely used to extract low potential heat from ground masses. In the over whelming majority of scientific works related to the numerical modeling of the operation of ground heat exchangers, the soil is considered as a continuous medium and heat transfer in it occurs only by thermal conductivity. In reality, soil is a porous medium, the pores of which can be filled with air and liquid. In this regard, in addition to thermal conductivity, heat transfer in the soil can also occur by convection of liquids or gas in a porous medium. Results. This paper presents the results of numerical modeling of the temperature regime of the soil U-tube heat exchanger, taking into account the free convective movement of the medium filling the pores of the soil. The system of equations describing this process consists of the equations of fluid dynamics in a porous medium and the energy equation. Attached to them is the heat transfer equation in a U-tube heat exchanger. Based on the results of solving this system of equations, the distributions of velocity and temperature in the porous soil medium, as well as the change in the temperature of the heating agent in the heat exchanger, are determined. It has been determined that the maximum velocity of the free convection flow of water in the pores under the observed conditions is of the order of ~ 10-6 m/s. Evaluation of the energy performance of the ground heat exchanger depending on the size of soil particles and its porosity showed that a larger volume of recoverable heat is provided with a smaller particle size and lower porosity. It is also shown that when the pores of the soil are filled with water, a larger volume of heat is extracted from the soil in comparison with the case of filling the pores with air.
{"title":"INFLUENCE OF SOIL FILTRATION PROPERTIES ON THE WORKING CHARACTERISTICS OF THE VERTICAL GROUND HEAT EXCHANGER","authors":"B. Basok, B. Davydenko, V. Novikov, H. Koshlak, A. Pavlenko","doi":"10.31472/ttpe.1.2022.9","DOIUrl":"https://doi.org/10.31472/ttpe.1.2022.9","url":null,"abstract":"Introduction. The purpose of these studies is to determine the effect of the filtration properties of soil as a porous medium on the performance of soil heat exchangers. Ground heat exchangers are important elements of heat pumps widely used to extract low potential heat from ground masses. In the over whelming majority of scientific works related to the numerical modeling of the operation of ground heat exchangers, the soil is considered as a continuous medium and heat transfer in it occurs only by thermal conductivity. In reality, soil is a porous medium, the pores of which can be filled with air and liquid. In this regard, in addition to thermal conductivity, heat transfer in the soil can also occur by convection of liquids or gas in a porous medium. \u0000Results. This paper presents the results of numerical modeling of the temperature regime of the soil U-tube heat exchanger, taking into account the free convective movement of the medium filling the pores of the soil. The system of equations describing this process consists of the equations of fluid dynamics in a porous medium and the energy equation. Attached to them is the heat transfer equation in a U-tube heat exchanger. \u0000Based on the results of solving this system of equations, the distributions of velocity and temperature in the porous soil medium, as well as the change in the temperature of the heating agent in the heat exchanger, are determined. It has been determined that the maximum velocity of the free convection flow of water in the pores under the observed conditions is of the order of ~ 10-6 m/s. \u0000Evaluation of the energy performance of the ground heat exchanger depending on the size of soil particles and its porosity showed that a larger volume of recoverable heat is provided with a smaller particle size and lower porosity. It is also shown that when the pores of the soil are filled with water, a larger volume of heat is extracted from the soil in comparison with the case of filling the pores with air.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84653042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The article presents the results of thermodynamic analysis of the theoretical model of the heat pump system of ventilation, air conditioning and dehumidification of the production room with variable values of internal moisture and heat generation during the transition and warm seasons. The influence of exhaust air energy recovery on the system efficiency is established and evaluated. As a prototype was adopted blacksmith shop, where it is necessary to maintain technological conditions (temperature and relative humidity). Calculations were performed using the method of successive approximations to estimate the air parameters at the nodal points of the system. This established the theoretical refrigeration efficiency of this system and showed the benefits of energy recovery to reduce energy consumption for the system. This model can be used for the design of air handling units with a set heat pump circuit.
{"title":"ENERGY ANALYSIS OF A HEAT PUMP AIR HANDLING UNIT FOR THE DEHUMIDIFICATION AND AIR CONDITIONING OF A PRODUCTION PREMISE","authors":"M. Bezrodny, T. Misiura","doi":"10.31472/ttpe.1.2022.7","DOIUrl":"https://doi.org/10.31472/ttpe.1.2022.7","url":null,"abstract":"The article presents the results of thermodynamic analysis of the theoretical model of the heat pump system of ventilation, air conditioning and dehumidification of the production room with variable values of internal moisture and heat generation during the transition and warm seasons. The influence of exhaust air energy recovery on the system efficiency is established and evaluated. As a prototype was adopted blacksmith shop, where it is necessary to maintain technological conditions (temperature and relative humidity). Calculations were performed using the method of successive approximations to estimate the air parameters at the nodal points of the system. This established the theoretical refrigeration efficiency of this system and showed the benefits of energy recovery to reduce energy consumption for the system. This model can be used for the design of air handling units with a set heat pump circuit.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82648245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The article is devoted to the study of the energy efficiency of the air conditioning system using a ground heat pump. The analysis of the English-language literary sources, which highlighted the features of the use of heat pump air conditioning systems in various climatic conditions. It is shown that the greatest effect from the use of such a scheme will be when the duration of the cold and hot periods is equal. The main temperatures at the nodal points of the circuit and the efficiency coefficient are determined. The dependences of the determining quantities on the parameters of the system are constructed. The proposed system has a significant positive effect compared to a standard split system, but it also has a drawback: for an air conditioning system with a ground source heat pump, the requirements for the thermal insulation of a building will be more stringent. Using the system all year round can significantly reduce the energy consumption for air conditioning. The application of such a solution at the design and geodetic development stage of the site will give a significant positive effect both in terms of operation and in terms of capital costs for the installation of the system.
{"title":"ENERGY EFFICIENCY OF USING A CON-DITIONING SYSTEM BASED ON A GROUND HEAT PUMP","authors":"M. Bezrodny, S. Oslovskyi","doi":"10.31472/ttpe.1.2022.6","DOIUrl":"https://doi.org/10.31472/ttpe.1.2022.6","url":null,"abstract":"The article is devoted to the study of the energy efficiency of the air conditioning system using a ground heat pump. The analysis of the English-language literary sources, which highlighted the features of the use of heat pump air conditioning systems in various climatic conditions. It is shown that the greatest effect from the use of such a scheme will be when the duration of the cold and hot periods is equal. The main temperatures at the nodal points of the circuit and the efficiency coefficient are determined. The dependences of the determining quantities on the parameters of the system are constructed. The proposed system has a significant positive effect compared to a standard split system, but it also has a drawback: for an air conditioning system with a ground source heat pump, the requirements for the thermal insulation of a building will be more stringent. Using the system all year round can significantly reduce the energy consumption for air conditioning. The application of such a solution at the design and geodetic development stage of the site will give a significant positive effect both in terms of operation and in terms of capital costs for the installation of the system.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74778635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The problems associated with the implementation of the strategy of low-carbon development of the economy of the world and Ukraine are noted, ways to reduce the carbon intensity of the economy are outlined, a new scientific direction is formulated and initially developed to establish and improve the energy efficiency of industry and the construction and housing sector, including end-users-regulators, active consumers. The main attention is paid to the development of energy efficiency (the main and cheapest energy resource) and the development of renewable energy - two basic directions for achieving a global decarbonized economy. At the same time, a positive feature of Ukraine is the presence of powerful nuclear generation and obligations to integrate energy systems with European ENTSO-E and ENTSO-G. It is noted that carbon neutrality is one of the UN sustainable development goals, which must be achieved with careful miscalculations of possible scenarios, while maintaining a balance between global environmental problems and the national interests of countries. Therefore, there should be joint economic growth with the reformatting of the energy system based on intelligent "green" technologies and also ensuring the principles of social justice.
{"title":"LOW CARBON ENERGY (REVIEW). 1. PROBLEMS AND FORECASTS","authors":"B. Basok, Ye.T. Baseyev","doi":"10.31472/ttpe.1.2022.4","DOIUrl":"https://doi.org/10.31472/ttpe.1.2022.4","url":null,"abstract":"The problems associated with the implementation of the strategy of low-carbon development of the economy of the world and Ukraine are noted, ways to reduce the carbon intensity of the economy are outlined, a new scientific direction is formulated and initially developed to establish and improve the energy efficiency of industry and the construction and housing sector, including end-users-regulators, active consumers. The main attention is paid to the development of energy efficiency (the main and cheapest energy resource) and the development of renewable energy - two basic directions for achieving a global decarbonized economy. At the same time, a positive feature of Ukraine is the presence of powerful nuclear generation and obligations to integrate energy systems with European ENTSO-E and ENTSO-G. It is noted that carbon neutrality is one of the UN sustainable development goals, which must be achieved with careful miscalculations of possible scenarios, while maintaining a balance between global environmental problems and the national interests of countries. Therefore, there should be joint economic growth with the reformatting of the energy system based on intelligent \"green\" technologies and also ensuring the principles of social justice.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"170 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86050443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Z. Petrova, І.V. Kuznietsova, А.І. Myrynin, Yu.P. Novikova
The gradient of values of water activity of the product and the corresponding humidity of the environment is the driving force of mass moisture exchange in various thermal and hydrothermal processes, as well as during storage, data on the water activity index are important. This indicator shows the amount of moisture retained in the test specimens, which may bind other compounds and affect the shape and structure of the test specimens, as well as the storage efficiency. Given the growing interest in fuel pellets, it is important to determine the rate of water activity. Composite granules based on obsolete sludge, peat and biomass (sawdust and buckwheat husks) were investigated. Measurement of thermodynamic parameters of the test samples was performed on a Hygrolab-2 instrument. Microscopic measurements were performed using a Delta Optimal Genetic Pro microscope connected to a computer. According to the generally accepted classification, fuel pellets belong to the tested samples with low humidity and brittle structure, which indicates a high calorific value. It is noted that the effect on the water activity index of sawdust content, which does not impair the quality of the studied samples but indicates a better ability to absorb moisture than its counterparts. Microphotographs of the granule samples show a significant pore space and a high sorption area, which can adsorb compounds both on the surface of the granules and in micro and mesopores. For the first time, the water activity index was determined for technical products, such as fuel pellets, the range of values of which is 0.224-0.231. Correlation coefficients are obtained, which have the same value for all types of granules. It is determined that the conditions of the technological process of obtaining fuel granules contributed to the formation of a porous structure, brittle and suitable for adsorption of compounds. This affects the storage conditions of the pellets and their mandatory observance.
{"title":"RESEARCH OF WATER ACTIVITY INDICATOR FOR MULOTORPHONE GRANULES","authors":"Z. Petrova, І.V. Kuznietsova, А.І. Myrynin, Yu.P. Novikova","doi":"10.31472/ttpe.1.2022.2","DOIUrl":"https://doi.org/10.31472/ttpe.1.2022.2","url":null,"abstract":"The gradient of values of water activity of the product and the corresponding humidity of the environment is the driving force of mass moisture exchange in various thermal and hydrothermal processes, as well as during storage, data on the water activity index are important. This indicator shows the amount of moisture retained in the test specimens, which may bind other compounds and affect the shape and structure of the test specimens, as well as the storage efficiency. Given the growing interest in fuel pellets, it is important to determine the rate of water activity. \u0000Composite granules based on obsolete sludge, peat and biomass (sawdust and buckwheat husks) were investigated. Measurement of thermodynamic parameters of the test samples was performed on a Hygrolab-2 instrument. Microscopic measurements were performed using a Delta Optimal Genetic Pro microscope connected to a computer. \u0000According to the generally accepted classification, fuel pellets belong to the tested samples with low humidity and brittle structure, which indicates a high calorific value. It is noted that the effect on the water activity index of sawdust content, which does not impair the quality of the studied samples but indicates a better ability to absorb moisture than its counterparts. Microphotographs of the granule samples show a significant pore space and a high sorption area, which can adsorb compounds both on the surface of the granules and in micro and mesopores. \u0000For the first time, the water activity index was determined for technical products, such as fuel pellets, the range of values of which is 0.224-0.231. Correlation coefficients are obtained, which have the same value for all types of granules. It is determined that the conditions of the technological process of obtaining fuel granules contributed to the formation of a porous structure, brittle and suitable for adsorption of compounds. This affects the storage conditions of the pellets and their mandatory observance.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82962805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of the work is to study the modes of motion of the phases at the interface of the film of water-air flow in the vertical channel during the countercurrent motion of the phases of the coolant. To achieve this goal, the following problems are solved: for each of the phases, the stationary Navier-Stokes equations and continuity are recorded, taking into account the direction of gravity. The obtained system of equations in the two-dimensional formulation in cylindrical coordinates with corresponding boundary conditions is solved in the package COMSOL MULTIPHYSICS 5.6. In the specified package the modeling of the influence of factors on the behavior of the interface of the film water-air flow in the vertical channel during the countercurrent movement of the phases is carried out. It is concluded that the existence of concomitant flows at the interface of the phases, depending on the height of the channel and the flow of phases in the vertical channel. As a result of the simulation, it was found that the countercurrent phases in the laminar mode in the vertical channel, the hydrodynamics at the interface of the phases differs in the height of the channel. At the inlet, at the bottom of the channel, the airflow creates a concomitant flow in the flowing film of water at the interface. Accordingly, at the top of the channel, at the inlet, the film of water creates a concomitant flow in the flow of wind, moving countercurrent. And in the canal itself, there is an area where the movement of water and air flows has no concomitant flows. That is, as a result of simulation it was found that the countercurrent phases in the laminar mode in the vertical channel, the hydrodynamics at the phase boundary differs, depending on the zone at the height of the channel and three such zones. Factors that affect the size of the above three zones are the height of the channel, flow rate, or speed of each of the phases. In particular, at the inlet of the water film into the channel with a speed = 0,3…1,1 m/s and a thickness of 0.25 mm (= 60… 210), the calculated value of the thickness of the concomitant airflow is (0.4 .. 1.6) 103 m and is directly proportional to the speed of the water film. Also, with a decrease in the height of the canal three times, from 0.150 to 0.050 m, the existence of three zones in the canal is maintained, but the height of the zone without concomitant flow decreases in direct proportion by one order - from 0.137 m to 0.0113 m. The establishment of co-directed flows at the phase separation boundary in the channels of film contact devices for selection of the hydrodynamic regime to increase the efficiency of heat exchange.
{"title":"THE SIMULATION AND FEATURES OF COUNTERCURRENT FLOW IN VERTICAL CHANNELS OF CONTACT DEVICES","authors":"I. Kuzmenko","doi":"10.31472/ttpe.1.2022.3","DOIUrl":"https://doi.org/10.31472/ttpe.1.2022.3","url":null,"abstract":"The aim of the work is to study the modes of motion of the phases at the interface of the film of water-air flow in the vertical channel during the countercurrent motion of the phases of the coolant. To achieve this goal, the following problems are solved: for each of the phases, the stationary Navier-Stokes equations and continuity are recorded, taking into account the direction of gravity. The obtained system of equations in the two-dimensional formulation in cylindrical coordinates with corresponding boundary conditions is solved in the package COMSOL MULTIPHYSICS 5.6. In the specified package the modeling of the influence of factors on the behavior of the interface of the film water-air flow in the vertical channel during the countercurrent movement of the phases is carried out. It is concluded that the existence of concomitant flows at the interface of the phases, depending on the height of the channel and the flow of phases in the vertical channel. \u0000As a result of the simulation, it was found that the countercurrent phases in the laminar mode in the vertical channel, the hydrodynamics at the interface of the phases differs in the height of the channel. At the inlet, at the bottom of the channel, the airflow creates a concomitant flow in the flowing film of water at the interface. Accordingly, at the top of the channel, at the inlet, the film of water creates a concomitant flow in the flow of wind, moving countercurrent. And in the canal itself, there is an area where the movement of water and air flows has no concomitant flows. \u0000That is, as a result of simulation it was found that the countercurrent phases in the laminar mode in the vertical channel, the hydrodynamics at the phase boundary differs, depending on the zone at the height of the channel and three such zones. \u0000Factors that affect the size of the above three zones are the height of the channel, flow rate, or speed of each of the phases. In particular, at the inlet of the water film into the channel with a speed = 0,3…1,1 m/s and a thickness of 0.25 mm (= 60… 210), the calculated value of the thickness of the concomitant airflow is (0.4 .. 1.6) 103 m and is directly proportional to the speed of the water film. Also, with a decrease in the height of the canal three times, from 0.150 to 0.050 m, the existence of three zones in the canal is maintained, but the height of the zone without concomitant flow decreases in direct proportion by one order - from 0.137 m to 0.0113 m. \u0000The establishment of co-directed flows at the phase separation boundary in the channels of film contact devices for selection of the hydrodynamic regime to increase the efficiency of heat exchange.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91336739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of the work is to develop recommendations for Ukraine to accelerate the involvement of biofuels in the transport sector. The current state and prospects of the introduction of renewable energy in the transport sector of the European Union are analyzed. It is shown that the fulfillment of the ambitious goal of the European Green Deal to achieve climate neutrality in Europe by 2050 largely depends on the success of reducing carbon dioxide emissions on transport. This sector is the most difficult to decarbonize compared to others, so the European Green Deal pays special attention to it. In Ukraine, the situation is similar: the introduction of renewable energy is the slowest in the field of transport compared to the sectors of electricity and heat production. In order to effectively attract renewable energy sources to the transport sector, it is recommended to pursue a consistent policy of stimulating this sector, taking into account the example of the EU and individual member states. For example, Sweden has already achieved about 30% of renewable energy consumption on transport, which is the highest index in the EU. The main mechanisms that have contributed to this are the long-established energy and carbon taxes on fossil fuels. Taking into consideration the sustainability requirements for biofuels of the RED II Directive, which may become mandatory in Ukraine in the future, it makes sense today to explore the possibilities and introduce support for the production of second-generation biofuels in Ukraine.
这项工作的目的是为乌克兰制定建议，以加速生物燃料在运输部门的参与。分析了欧盟运输部门引入可再生能源的现状和前景。研究表明，实现《欧洲绿色协议》(European Green Deal)到2050年在欧洲实现气候中和的宏伟目标，在很大程度上取决于能否成功减少交通运输中的二氧化碳排放。与其他行业相比，这一行业是最难脱碳的，因此《欧洲绿色协议》特别关注这一行业。在乌克兰，情况也类似:与电力和热力生产部门相比，运输领域引入可再生能源的速度最慢。为了有效地吸引可再生能源进入运输部门，建议在考虑到欧盟和个别成员国的例子的情况下，采取一致的政策来刺激这一部门。例如，瑞典已经在交通运输上实现了约30%的可再生能源消耗，这是欧盟最高的指标。造成这种情况的主要机制是长期以来对化石燃料征收的能源税和碳税。考虑到RED II指令对生物燃料的可持续性要求，这可能在未来成为乌克兰的强制性要求，今天探索乌克兰生产第二代生物燃料的可能性并引入支持是有意义的。
{"title":"CURRENT SITUATION AND PROSPECTS OF RENEWABLE ENERGY USE IN THE TRANSPORT SECTOR","authors":"T. Zheliezna, A. Bashtovyi","doi":"10.31472/ttpe.1.2022.5","DOIUrl":"https://doi.org/10.31472/ttpe.1.2022.5","url":null,"abstract":"The aim of the work is to develop recommendations for Ukraine to accelerate the involvement of biofuels in the transport sector. The current state and prospects of the introduction of renewable energy in the transport sector of the European Union are analyzed. It is shown that the fulfillment of the ambitious goal of the European Green Deal to achieve climate neutrality in Europe by 2050 largely depends on the success of reducing carbon dioxide emissions on transport. This sector is the most difficult to decarbonize compared to others, so the European Green Deal pays special attention to it. In Ukraine, the situation is similar: the introduction of renewable energy is the slowest in the field of transport compared to the sectors of electricity and heat production. In order to effectively attract renewable energy sources to the transport sector, it is recommended to pursue a consistent policy of stimulating this sector, taking into account the example of the EU and individual member states. For example, Sweden has already achieved about 30% of renewable energy consumption on transport, which is the highest index in the EU. The main mechanisms that have contributed to this are the long-established energy and carbon taxes on fossil fuels. Taking into consideration the sustainability requirements for biofuels of the RED II Directive, which may become mandatory in Ukraine in the future, it makes sense today to explore the possibilities and introduce support for the production of second-generation biofuels in Ukraine.","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"198 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76958020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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