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Year 2015

Volume 51 Issue 5


Section 1. Refrigeration engineering


O. Ostapenko, O. Yakovleva, M. Khmelniuk, O. Zimin

OPTIMAL PROCESS SYSNTHESIS FOR REFRIGERATION SYSTEM OF ASSOCIATED GAS LOW-TEMPERATURE CONDENSATION PLANT

Design of modern high-efficient systems is a key priority for the Energy Sector of Ukraine. The cooling technological streams of gas and oil refineries, including air coolers, water cooling and refrigeration systems for specific refrigerants are the objectives of the present study. Improvement of the refrigeration unit with refrigerant separation into fractions is mandatory in order to increase cooling capacity, lowering the boiling point of coolant and increasing the coefficient of target hydrocarbons extraction from the associated gas flow. In this paper it is shown that cooling temperature plays significant role in low-temperature condensation process. Two operation modes for refrigeration unit were proposed: permanent, in which the concentration of the refrigerant mixture does not change and dynamic, in which the concentration of refrigerant mixtures depends on the ambient temperature. Based on the analysis of exergy losses the optimal concentration of refrigerant mixtures propane/ethane for both modes of operation of the refrigeration unit has been determined. On the basis of the conducted pinch-analysis the modification of refrigeration unit with refrigerant separation into fractions was  developed. Additional recuperative heat exchangers for utilization heat were added to the scheme. Several important measures to increase the mass flow rate of refrigerant through the second section of the refrigeration centrifugal compressor from 22.5 to 25 kg/s without violating the agreed operational mode of the compressor sections were implemented.

Keywords: propane/ethane; refrigerant mixture; exergy losses; centrifugal compressor; refrigerant concentration; refrigerant fractionation; pinch analysis; low-temperature condensation.

DOI: 10.15673/0453-8307.5/2015.44793

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A. S. Titlov, G. V. Shlapak

CHAMBERS DEVELOPMENT BASED absorption refrigeration units for low-temperature processing and storage of meat and fish production in conditions of peasant farmers

New designs of universal cameras with absorption cooling units, which use modern technical and technological solutions (removal of the evaporator outside the refrigerating chamber, the heat transfer systems based on heat pipes, cold-accumulating materials, effective contact fillers based on the porous compressible material) are presented in the paper. The results of experimental studies of such cameras on the example of the low-temperature processing (frozen) of meat products simulators are shown. Examples of the utilization of low-temperature cameras in the farm conditions are given.

Keywords: propane/ethane; refrigerant mixture; exergy losses; centrifugal compressor; refrigerant concentration; refrigerant fractionation; pinch analysis; low-temperature condensation.

DOI: 10.15673/0453-8307.5/2015.51857

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L. I. Morosuk

THERMODYNAMIC ANALYSIS OF MACHINES FOR generating HEAT AND COOD ON TWO TEMPERATURE LEVELS for EACH thermal effect

The perspectives in the field of heat pumps and refrigeration systems are associated with implementing new working fluids as well as developing the schematics of the machines working on novel thermodynamic cycles. One of the promising approaches is the development of the cogeneration machines (for different industrial technological processes) with multi thermal effects. In this paper, the principles of the machines working on inverse thermodynamic cycles with four temperature levels (two high-temperature and two low-temperature) have been evaluated. The synthesis of the generalized schematic and corresponding thermodynamic cycle for the mixtures of insoluble components as the working fluid has been carried out based on the “cycle method” of the thermodynamic analysis. The thermodynamic modeling is proposed using the principle of equivalent replacement of complex processes associated with the mixture by simple processes associated with the one-component working fluids. As an example, the machine with the mixture of R717 / R123 is analyzed.

Keywords: “cycle method”, mixtures of insoluble components, schematic and corresponding thermodynamic cycle of machine.

DOI: 10.15673/0453-8307.5/2015.44774

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Section 2. Power engineering and energy saving


  V. V. Milovanova

QUALITY IMPROVEMENT OF CARS BY MEANS OF FUEL CELLS UTILIZATION

A review of the existing types of fuel cells, their advantages and disadvantages, as well as the prospects for their use in the automotive industry has been carried out in the paper. General problems that make it difficult to launch fuel cell vehicles in series production are analyzed, some suggestions for dealing with them are proposed. Examples of application of fuel cells in cars today and a forecast of development of these technologies in the future are given.

Keywords: fuel cells, alternative power generation technology, automobile production

DOI: 10.15673/0453-8307.5/2015.44792

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  A. Doroshenko, V. Kirillov, K. Lyudnitskij

solar MULTI-STAGE REFRIGERATION SYSTEMS. NEW DEVELOPMENTS AND POSSIBILITIES ANALYSIS

The developed schematics for the solar refrigeration systems, based on the use of absorbing cycle and solar energy for the regeneration of absorbent solution are presented in the article. Cascade (two-stage) principle of construction of contours is used with growth of concentration of absorbent on the stages of cascade. The solar absorbing systems in the basic variants of cooling and air-conditioning are developed. Heat-mass-transfer apparatus of film-type, entering in the complement of contours compatible and executed on the basis of multichannel compositions from polymeric materials. The features of film-type flows in the heat-mass-transfer apparatus of the basic solar systems are considered theoretically. Experimental research of processes of heat and mass transfer in the apparatuses of drying (absorber) and cooling (evaporated coolers of air and water of direct and indirect types) contours of the solar system is executed. On the basis of findings on efficiency of processes the comparative analysis of the solar refrigeration and air-conditioning systems possibilities is carried out. Positive influence of growth of concentration of absorbent from the first to the second stage of cooling is shown. The preliminary comparative analysis of the solar refrigeration systems possibilities is proposed.

Keywords: Solar systems, drainage of air, cooling of environments, heat-mass-transfer apparatus, film-type flows, absorption, desorption, evaporated cooling

DOI: 10.15673/0453-8307.5/2015.46120

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  O. A. Titlova

ALGAE AS AN ALTERNATIVE SOURCE OF ENERGY

Today humanity is beginning to understand the consequences of ill-considered use of energy resources. In the last decade  a new direction of the economy is actively developing – «The Blue Economy». Its aim is to find innovative solutions that are safe for the environment and society. Bioenergy is one of the directions of the «Blue Economy» which is actively developing lately. The article discusses the possibility, advisability and examples of the algae use as a feedstock for the energy resources production: the concept of a new generation of house – «BIQ house», which is powered by energy from microalgae which is in its panels; production of oil and gas in specialized reactors. The different ways of growing the biomass required to biofuels production and the use of such technologies in Ukraine are considered.

Keywords: «The Blue economy», bio-energy, algae, biomass, biofuels, BIQ house, bioreactors.

DOI: 10.15673/0453-8307.5/2015.51937

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 Section 3. Refrigerating and accompanying technologies


  T. V. Diachenko,  A. O. Kolesnik

AEROGEL AS A PERSPECTIVE MATERIAL FOR ISOLATION PRODUCTION OF LIQUEFIED NATURAL GAS TRANSPORT CAPACITIES

The paper is devoted to research of different types of isolation which is applied in the production process of tanks for methane carriers. The calculations technique is developed and settlement researches of a daily evaporability and metal consumption for five types of isolation are conducted: the powder and vacuum; the screen and vacuum; the polyurethane foam; the glass foam and the aerogel. The analysis of results has shown that the aerogel is a perspective view of thermal isolation for use in cryogenic capacities for liquefied natural gas transportation.

Keywords: Liquefied natural gas – Thermal insulation – Tanker – Methane Carrier – Daily evaporation – Metall Consumption

DOI: 10.15673/0453-8307.5/2015.44796

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N.N. Lukianov, А.V. Меlnyk, V.P.Zhelezny, О.Ya. Khliyeva, А.S. Moroz

INFLUENCE OF COMPRESSOR OIL AND TIO2 NANOPARTICLE ADDITIVES ON THE REFRIGERANT FLOW BOILING HEAT TRANSFER COEFFICIENT INSIDE HORIZONTAL TUBES

The results of a comprehensive experimental and theoretical study of the effect of compressor oil and TiO2 nanoparticle additives in isobutane on the local flow boiling heat transfer coefficients in the tube have been presented in the paper. The preparation of the working fluid (R600a / mineral oil / TiO2 nanoparticles) for systems with hermetic compressor Atlant CKH 150 has been described. The experimental data were approximated by the model that take into consideration the effect of oil and nanoparticle additives in the refrigerant on the local flow boiling heat transfer coefficient in the tube for solutions R600a/oil and R600a/oil/nanoparticle TiO2. It was shown that the TiO2 nanoparticle additives at concentration 0.0026 - 0.006 % wt. in the working fluid R600a / mineral oil does not influence on the values of the local flow boiling heat transfer coefficient in the tube.

Keywords: Nanofluids - Refrigerant / oil solutions - Boiling heat transfer - Heat transfer coefficient - Experiment - Calculation methods

DOI: 10.15673/0453-8307.5/2015.44790

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Y. D. Kotukov, V. I. Levchenko, O. V. Rogankov, M. V. Shvets, V. B. Rogankov

CONCEPT AND MODEL OF MESOSCOPIC POROSITY FOR THIN PERMEABLE MEDIA

There are two main obstacles to perform the objective comparison and choice of preferable variant within the set of appropriate textile materials (TM), related to the thin permeable media: 1) the different experimental methodologies and tools usable by different authors for an estimate of water-vapor-transmission rate; 2) the different ambient conditions of such measurements and a variety of experimental means proposed, at present, for an estimate of TM-porosity. Recently we have studied, in detail, the former factor [V.B. Rogankov et al, Refrigeration Engineering and Technology, 51(1), 2015, pp.47-54] and pointed out the possible strategy to overcome this obstacle. In this work we will pay the main attention to the latter factor. The novel concept of mesoscopic (nano-) porosity of threads is formulated for any woven and non-woven TMS. The resulting alternate basic (AB-) model for theoretical estimate of effective (observable) porosity in hydrophilic and hydrophobic permeable media is developed. It is based, exclusively, on the standard (but the measuring-laboratory-condition’s-dependent) measurements of so-called square mass and thickness for the wide set of 41 samples taken from 5 different experimental works. The proposed treatment of such data leads to the simple, well-founded relationships of AB-model without any adjustable coefficients. They provide a possibility to obtain the reliable estimates for the following fundamental TM-characteristics: density of moist and/or dry matrix; observable effective porosity at any level of ambient moisture; maximum hygroscopicity without the additional experiments.

Keywords: standard porosity; hydrophilic and hydrophobic media; effective porosity; alternate basic model of permeable media.

DOI: 10.15673/0453-8307.5/2015.44797

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 Section 4. Automatic, computer and telecommunication technologies


V. Mikhailenko, N. Kniazieva, M. Solodovnik

INTELLIGENT SYSTEM OF THE SOLID FUEL COMBUSTION PROCESS CONTROL IN THE FLOW STEAM GENERATOR OF THERMAL POWER-STATION

The analysis of the efficiency of domestic and foreign coal-fired thermal power plants, which use modern innovative technology, demonstrates the advantage of the latter by an average of 3-7%. In this connection there is a scientific challenge of steam generators thermal processes re-regulation system effectiveness improvement on the basis of  intelligent systems of control the solid fuels combustion process. Intelligent automatic control system operates on the basis of the fuzzy logic theory and has the ability to adjust the fuel consumption because of possibility of taking into account its physical and chemical properties. Developed knowledge base of fuzzy controller and proposed structure of the intellectual automatic control systems of combustion process. ACS will allow improving fuel combustion processes and making savings in the base mode and adjusting mode.

Keywords: steam generator  –  control system  –  the combustion process  –  a fuzzy controller.

DOI: 10.15673/0453-8307.5/2015.44795

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V .V. Antoniuk,  O. V. Drozd, M. O. Drozd,  I. M. Nikolenko

ASSESSMENT OF OBSERVABILIТY FOR ТНЕ POINTS OF А PIPELINE CIRCUIT OF ТНЕ DIGITAL COMPONENTS IN SAFETY­RELATED SYSTEMS

А problem of the hidden  faults without solving of which the  fault tolerant structure of the digital сотponents does not guarantee  function safety of the safety­critical systems is considered. The  problem is shown in the potentially hazardous circuit points, which in а normal mode сап accumulate the hidden faults reducing the  fault tolerance of the digital component at transition to ап emergency mode of the system operation. А model of the activated path for pipeline circuit of the digital component is offered. It allows determining input data for calculation of point observability in modes of the system. А method of potentially hazardous point identification for pipeline circuit of the digital component is developed.

Keywords: Safety­critical system ­ Digital component ­ Pipeline circuit ­ Нidden fault ­ Potentially hazardous points ­ Model of the activated path.

DOI: 10.15673/0453-8307.5/2015.51952

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V. V. Trandafilov, M. G. Khmelniuk

COMPUTER SIMULATION OF A STIRLING REFRIGERATING MACHINE

In present numerical research, the mathematical model for precise performance simulation and detailed behavior of Stirling refrigerating machine is considered. The mathematical model for alpha Stirling refrigerating machine with helium as the working fluid will be useful in optimization of these machines mechanical design. Complete non-linear mathematical model of the machine, including thermodynamics of helium, and heat transfer from the walls, as well as heat transfer and gas resistance in the regenerator is developed. Non-dimensional groups are derived, and the mathematical model is numerically solved. Important design parameters are varied and their effect on Stirling refrigerating machine performance determined. The simulation results of Stirling refrigerating machine which include heat transfer and coefficient of performance are presented.

Keywords: Stirling refrigerating machine – Mathematical model – Dimensionless characteristics – Energy efficiency – Helium

DOI: 10.15673/0453-8307.5/2015.39293

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