Refrigeration engineering and technology

10 - 13

Authors: A.S. Boychuk

Equations for thermal conductivity of alternative refrigerants R32and R125 for variable temperature and density were worked out. The reliable equation of state was used for each refrigerant. Coefficients of the equations were determined by least-square method on the experimental data. The equations describe the thermal conductivity in the temperature range from 223 to 466 K at pressure up to 50 MPa for R32and from 228 to 513 K at pressure up to 53 MPa for R125. The accuracy of the equations is acceptable for engineering calculations.

20 - 25

Authors: А.N. Radchenko; A.V. Grich

Based on the analysis of the cooling performance of trigeneration system gas engine room intake air the rational way of cooling by supplying a cooled intake air to the inlet of turbochargers and to the alternators and cylinder heads of the cogeneration gas modes and ventilation of the main volume of engine room was developed.

32 - 42

Authors: A.V. Doroshenko; K.V. Lyudnitskij

The worked out schematics for the alternative refrigeration systems and air-conditioning systems, based on the utilization of absorption cycle and solar energy for the regeneration (renewals) of absorbent solution were presented in the paper. Factorable principle of construction of all heat-mass-transfer apparatuses is used with varying of both temperature level and growth of absorbent concentration on the cascade stages. Heat-mass-transfer apparatuses are compatible and executed on the basis of multi-stage monoblock compositions from polymeric materials. The preliminary analysis of possibilities of the solar systems was executed as it applied to the tasks of environments cooling and air-conditioning.

47 - 53

Authors: S.V. Artemenko

The review of recent papers related to modeling of refrigerant properties using artificial neural networks as an alternative to conventional thermodynamic approach for modeling prediction of thermodynamic properties of refrigerants has been given in the paper. The study also discusses efficiency, adequacy and limitation of this approach.

59 - 66

Authors: M.A. Kolosov; V.Yu. Emelianov

One-dimensional transient thermal model of the lengthy HTS conductor using thermoresistive effect to measure the level of cryogenic liquid was created. Resulting model made it possible to determine the distribution of pace-tures along the length of the HTS conductor and other characteristics. The comparing-of calculated and experimental data obtained at an atmospheric dewar with liquid nitrogen was carried out.

71 - 74

Authors: S.V. Sakharova; S.V. Rybka

The subject of the research, some results of which are presented in this paper, is focused on the development of modern telecommunication networks in Ukraine and allows solving the problems at the networks design and organization of access to infocommunication services. The chosen theme is closely related with the main directions of the world telecommunications development, which are defined in the main existing regulations and laws. A characteristic feature of computer information systems’ progress, which are actual in Ukraine, is an absolute priority of expert systems’ development. Questions of the expert systems’ usage at the design and development of telecommunications networks in the modern world are considered in the paper. The problem of expert system’s development, which allows enhancing of the design and operation of telecommunication and access networks, is being solved within the given work. Statement of the problem is limited by the development of the algorithm for the expert system’s development and analysis of the theoretical aspects of the knowledge based intelligent system’s design. Done work formulates the qualimetry problems and helps to understand how to build an expert system for the access networks’ rational development. Expert system, allowing to choose proper access technology, is developed as an example. Particularly DSL technologies are considered at the first stage. The last mile is quite specific network’s segment. It should have enough bandwidth while providing great transmission range without regenerators. This expert system will determine the best option of DSL technology on the basis of the desired properties. The system is developed with the usage of Expek Pro software (version 1.5+) for Windows. The article consists of five sections - introduction, problem statement, the main part - the necessity of an expert system’s development for the telecommunication networks’ design, an example of the developed expert system and conclusions, as well as includes bibliography, used at the work writing.

12 - 16

Authors: D.K. Kuleshov; I.N. Krasnovskiy

Practical application of TiO2 nanoparticles doping for domestic refrigerator working with isobutene is considered. Experimental studies of energy consumption This work has demonstrated that nanoparticles can improve the performance of the refrigerator. The energy consumption test was conducted to compare the performance of the refrigerator with nano-refrigerant and pure refrigerant so as to provide the basic data for the application of the nanoparticles in the refrigeration system. It was demonstrated the nanoparticle doping reduces energy consumption of refrigerator ДХ-271 010 D 256/255/465 N/ST2,0 A+about 4,7% at 0,05% nanoparticle concentation.

23 - 29

Authors: L.I. Morosuk

Heat-using refrigeration machines are a particular case of energy conversion systems working on the inverse thermodynamic cycles. The primary energy for such machines is thermal energy. The heat-using refrigeration machines can be divided into the three groups according to the so-called compensation process: (a) sorption (ab-sorption and ad-sorption) with thermochemical compression, (b) ejection with jet-compression, and (c) compression with mechanical compression/expansion. Development in the field of absorption refrigeration machines associates with using the water-ammonia mixture as a working fluid as well as with utilization of special schematics related to (a) rectification/dephlegmation processes and absorption process, and (b) absorption-compression machines that are most effective as low-temperature refrigeration machines and high-temperature heat pumps. Development in ejection machines goes to the direction of machines with (a) small refrigeration capacities, (b) using the natural working fluids, and (c) implementation of the renewable energy sources with different temperature levels. Development in compression heat-using refrigeration machines associates with (a) using carbon dioxide as a working fluid, (b) implementation of renewable energy sources, and (c) extended possibilities to use these machines within the tri-generation systems. Development and improvement in the field of the heat-using refrigeration machines and heat pumps are the result of long-term and successful theoretical and experimental research has been conducted in the chair “Refrigeration machines and installations” at Odessa National Academy of Food Technologies.

37 - 42

Authors: O.S. Solomakha; E.V. Novakivskyy; O.M. Nedbailo

We consider mitigation of heat consumption for heating by conventional energy by using low-grade energy in the soil thermal barrier. Thermal barrier is a system of pipelines, which is located in the opaque envelope between the insulation and bearing walls. Feed warm or cold coolant in the winter or summer respectively can reduce heat loss or heat leakage everywhere envelope. The paper investigates the heat loss through the envelope with thermal barrier, temperature distribution inside the wall, depending on the ambient temperature. The influence of the thickness of the bearing wall envelope and insulation thickness on the temperature distribution in the middle of the wall Found minimum coolant temperature in the thermal barrier and the analysis of the transformation coefficient of thermal heat pump capacity building needs of the coolant at the inlet of the thermal barrier. Constructed depending the heat and heat the room, depending on the volume of heat thermal barrier. Energy savings are calculated as a percentage of heating and cooling, depending on the volume of heat (heat consumption) thermal barrier in the summer and winter periods.

51 - 54

Authors: A.M. Yakimets; H.G. Abdulkareem

The possibility of difference in EMF and traditional conditions and possibility of determining the difference calculating power at any variants education parallel branches arbitrary multi-phase windings and the possibility of a difference in traditional EMF conditions taking into account the characteristics of their manifestations in synchronous machines considering additional harmonics of the magnetic field.

61 - 68

Authors: V.L. Bondarenko; S.V. Artеmenko; E.G. Korzh

Improvement of installation for enrichment of inert gases (krypton and xenon) requires knowledge of properties for components of air and based on it mixtures. Review of equations of state is presented in this study. The methods and calculations for phase equilibira diagram for binary mixtures Kr-Xe, Kr-O2and Kr-N2are performed on the base of Soave – Redlich – Kwong equation of state. Results of calculations are in agreement with experimental data. The model developed in this study is applicable for elaboration of properties of multicomponent krypton and xenon concentrates mixtures

73 - 76

Authors: J. Kozonova; D. Prutz

In this article the assortment sport drinks’ extending possibility is represented. The juice component compositions for sport drinks with different osmolality were designed. The feasibility of adding into the drink calcium lactate as a source of quick body energy renovation and as calcium deficiency’s reducer were proved.

13 - 17

Authors: Т.V. Morosuk

During last decades, the exergetic method of the thermodynamic analysis became very popular among the researches, particularly working in the field of refrigeration. Well known, that the information obtained from the exergetic analysis cannot be provided by any other methods of thermodynamic analysis, for example, energy analysis. However, the conventional exergetic analysis has some limitations. In order to overcome these limitations, an advanced exergetic analysis has been proposed. The introduction of the advanced exergetic analysis should help engineers and designers in their practical work.

22 - 29

Authors: A.V. Ovsyannik; E.N. Volkova; T.S. Naumova; V.G. Yakimchenko

Heat exchange experimental research results during refrigerants R404а, R407с and R410a boiling on smooth technically roughened surface in free movement conditions in large volume are presented. The dependencies between the quantitative characteristics of the boiling heat transfer process, security settings, and other factors affecting the intensity of heat transfer are established.

37 - 40

Authors: V.V. Klуmenko; M.V. Bosiy; V.P. Parafiynyk; S.О. Prylypko

The way of ensuring of gas turbine drive (GTD) efficiency with fuel gas presence, pressure of which is lower than technologically permissible in the fuel gas gasturbine drive combustion chamber on the basis of gas hydrate technology has been considered. The schematic of fuel gas gashydrate booster device (FGGBD) is given and gas turbine drive with FGGBD operation principle is reported. The FGGBD operating cycle is also shown for the specific composition of fuel gas, its initial pressure and pressure in the combustion chamber of a gas turbine drive. The thermodynamic parameters of the cycle reference poins are determined.

47 - 53

Authors: V.Y. Labay; D.I. Harasym

In modern technologies, which are related to energy transformation, namely in the air conditioning systems, important place is occupied by objects creation and improvement of which requires the use of innovation thermodynamics. Classic apparatus of this science is often insufficient to solve new tasks; it is necessary not only to its further development, but its combination with the elements of a systematic approach and energetics. Innovation mathematical research model of the central straight flow air conditioning system for cleanroom in order to computer’s estimation its energy effective by virtue of exergetic output-input ratio depending on different factors, which have influence on its work, was described in this article. The dependence of exergetic output-input ratio for chosen air conditioning system е on temperature difference between the inside and the supplied air tS tin tS, depending on excess heat in the cleanroom, and moisture content dout of outdoor air was defined thanks to this model. It is shown that the chosen air conditioning system should be preferably used at higher temperature difference between the inside and the supplied air, namely, for example tS = 6,0°С (respectively outdoor air temperature tout = 42°С), that will give the opportunity to gain the highest exergetic output-input ratio е , which means to gain the most advantageous economical variant of exploitation of chosen air conditioning system.

58 - 64

Authors: А. Gurskiy; V. Denisenko; A. Goncharenko

Characteristics of the Odessa Port Plant turbo-compressor unit for ammonia re-loading are discussed in the article. Analysis of operating power efficiency of the unit for ammonia re-loading is given. On the basis of the analysis the method for determining indirect parameters of unit functioning and its utilization in the control system is presented. The virtual stall designed for the study of refrigerating turbo compressor control system with readings of deficiencies on the parameters ratio for evaluation of operating modes is also introduced.

10 - 14

Authors: D. Kuleshov; V. Mazur

The working fluid selection in the vapour compression refrigeration cycles has been studied as a fuzzy thermoeconomic optimization problem. Three criteria: thermodynamic (COP Coefficient Of Performance), economic (LCC Life Cycle Cost), and ecologic (GWP – Global Warming Potential) are chosen as target functions. The decision variables X as an information characteristics of desired refrigerant are presented by its critical parameters and normal boiling temperature. Local criteria are expressed via thermodynamic properties restored from information characteristics of refrigerant X, as well as life cycle costs are calculated by the standard economic relationships. GWP values are taken from the refrigerant database. Class of substances under consideration is presented by the natural refrigerant R600a embedded with nanostructured materials.

22 - 26

Authors: V. Kogut; V. Minienkov; M. Khmelniuk

This paper describes the use of a heat-exchanger ejector device for air humidification in a refrigeration treatment camera of meat half-carcasses, and the possibility of its application for artificial snow. The system of a two-step meat moistening in the isolated compartment by treating meat with a mixture of cooled air and the fine crystal ice particles is represented in this article. The design scheme and the principle of the heat exchanger ejector is shown. The ice crystals formed at the outlet of the diffuser of the heat exchanger-ejector from the mixture of injected water droplets through the nozzle into the incoming stream of compressed cooled air. Application of a heat exchanger-ejector allows to get 100% relative humidity in the chamber. Heat exchanger ejector can be used for meat stacks snowing.

35 - 38

Authors: V.А. Аrsіry; V.О. Мakarov; Y.N. Serbova; О.V. Vishnevskaya

In the thermal power plants and heating plants about 30% of the total cost of energy for their own needs is spent on the forced-draft system. When these systems were designed and was created the basic capacity thermal power complex, as blowers were used forced-draft machines: VD series draft fans and exhaust fans series D. Development of fan structure and aerodynamics оf the blade flow in the impeller predetermined ineffectiveness of used impeller design with forward curved blades and approved the higher performance for fans with backward curved blades. In order to save energy sources instead of draft machines series VD and D mainly were used blowers series VDN and DN. Installation of new high-efficiency blowers led to efficiency increasing, but at the same time occurred a significant reduction of the boiler thermal rating. Focusing on maximum fan efficiency, modern blowers basically became a system limiting problem, which causes draft and forced draft systems production limiting. Analysis of aerodynamic parameters of the most common draft machines VD - 15,5 and VDN - 17 showed that on the characteristics of the VD - 15,5 with rotations n = 730 rev / min in maximum efficiency ηv = 70%, the fan supplies Q ≈ 65 K. m3/hr and at maximum efficiency fan VDN- 17 efficiency ηv = 85%, the supply in the zone of maximum efficiency does not exceed Q ≈ 56 К. m3/hr. According to the comparison of the parameters can be seen that blowers performance with forward curved blades is up by 20% and the efficiency is 15% lower. Selection priority in the process of design and modernization of forced draft systems between two types of fans still has not been resolved. Therefore to summarize and derive concepts to solve the problem of optimal choice of a blower were made the following general conclusions: - Changing the approach to the economic value of optimal operating mode TDM providing their stable work will partially solve the nominal power derating problem of heating boilers and thermal power plants; - Indication of the aerodynamic efficiency of the systems is still efficiency blowers - fans or smoke exhausts that doesn’t fully reflect processes in the power systems, as blowers are only part of the complex processes of compression and transportation of air or flue gas; - It is advisable to analyze the representations of forced-draft parameters of the boilers, and the calculation of the efficiency of their work in order to have more accurate representation of the characteristics of blowers as well as individual sections of aerodynamic systems.

44 - 52

Authors: A.V. Doroshenko; Amina Abdessemed

The concept of evaporating cooling gases on the basis of the new generation multichannel polymeric structures is developed. Natural cooling limit in such systems is the dew point of the ambient air, which significantly extends the capabilities of evaporative cooling technology in general and allows to solve a number of problems of refrigeration and air-conditioning with a significant reduction in energy costs for implementing the processes. Special attention is paid to the water vapor re-condensation during the transition to the deep evaporative cooling of media. On the basis of the authors theoretical and experimental data, preliminary analysis of such refrigerants possibilities with respect to evaporative cooling problem solving is performed.

57 - 59

Authors: V.G. Marchenko; A.I. Lipa; A.P. Ponomarenko

In the paper the experimental results of the different charge air ions distribution for working ionizer of effluence type in the office space are given. The study has been carried out using the ions generator IWS-12D1-AE (Israel) – corona type with the productivity of 5·109 ion/sec. The small air ions counter MAC-01 (Russia) was used for determination of ions concentration. The results are presented as scheme demonstrating the air ions distribution at various height and distance from the ionizer. The high local area concentration of negative air ions under the ionizer is detected. It is established that trajectory of air ions distribution from corona type ionizer IWS-12D1-AE is characterized by a parabolical shape. The concrete recommendations for the arrangement of this device are determined.

64 - 68

Authors: А.М. Kosmacheva; А.L. Tsikalo

XXI century – is a century of scientific and technical progress. Scientific researches that contribute the best technical development expose many-sided possibilities for work of modern and home enterprises. Products of their production provide the necessities of population, but here, natural resources are exhausted, an environment is contaminated, the places of dumps are increased, wastes utilization is small controlled. Taking into account these and many other questions by estimation and saving environmental preservation, where we live, there is a pressing question to reorganize the structure of SPZ of the dangerous enterprises and especially vulnerable objects with the purpose of maintenance of natural environment that will contribute the best existence of living objects.

73 - 76

Authors: G.S. Gaivoronska; A.A. Nazarenko

The article presents the studies results of some aspects of networks of the future design. In this paper, most attention is paid to routing protocols. This theme was chosen because of its significant relevance and importance of networks of the future design, as one of the priority directions of further development of information and communication technologies. Internet Engineering Task Force (IETF) published a series of recommendations related to routing protocols, in particular the recommendation RFC 2328 describes the protocol OSPF v2, recommendation RFC 1771 contains the basic provisions of the protocol BGP v4. Based on this information, as well as some other data were analyzed in order to select a routing protocol for a specific task. The paper presents the most famous routing protocols. Relevant protocols are OSPF and BGP v4, supporting a large number of network nodes with high reliability and low service traffic. For non-large networks often is used RIP v2 due to the simplicity of its realization. IS-IS protocol is currently not widely used because it does not satisfy a very important requirement for modern networks, namely not support IP-routing. Protocols IGRP and EIGRP are developed by Cisco and implemented, primarily, on their equipment. It should be noted that this study is directed primarily to show that the task of choosing a routing protocol is a controversial issue and has a large dependence on various factors. These factors include: the purpose of creating a network, the number of nodes in the network, the requirements for scalability and reliability, convergence. To solve global issues appropriate to apply protocols OSPF and BGP, while BGP is a major dynamic routing protocol in the Internet. By considering a particular example of a small corporate network, for which is not necessary to use such protocols like: OSPF and BGP v4, which will be characterized by high complexity for this situation, RIP v2 is best suited. Consequently, the value of this lies in correct, competent and flexible approach to the choice of routing protocol for each case, according to the recommendations of various standards organizations.

82 - 88

Authors: V.G. Tkachenco; O.V. Sinyavsky

The polygonal block nonlinear codes are defined in the article. The methods of certain polygonal codes constructing is considered and effective universal recursive method of codes of great length constructing on the basis of Steiner systems for cryptosystems with error correction is proposed. Cryptosystem with correction code based on this code is developed. The advantages of this cryptosystem are speed encryption and decryption, as well as the ability to change the code quickly without encryption and decryption tables changing.

11 - 15

Authors: N.V. Zhikhareva

Mathematical aspects of fruit-and vegetable storehouse refrigerating unit operating mode thermoeconomic analysis are considered in the study. The values of exergy flow and exergetic losses on the example of direct cooling refrigerating unit are determined..

27 - 35

Authors: O.A. Lisohurska; A.V. Doroshenko

The problem of gases and liquids evaporative coolers practical use area widening is associated with the reduction of the evaporative cooling limit from wet-bulb temperature to the dew point temperature of the outside air. This entails a risk of water vapor recondensation when approaching the equilibrium curve. The application of the "enthalpy potential" method to the availability of the water film thermal resistance, which is neglected in traditional calculations of the evaporative coolers is considered in the paper. The developed method allows to analyze the change of air flow state when it is in the directly contact with the liquid film, which is essential for deep cooling of a liquid (when the limit is the dew point temperature and the line of air state changes is coming directly to φ = 100 %). An equation expressing the additive phase resistance was received, and it is shown that the value of the thermal resistance of the liquid is up to 50 % of the total thermal resistance, that is nonnegligible, as assumed in the traditional evaporative coolers calculations. On the basis of experimental data the authors analyzed the influence of the contacting gas and liquid flows ratio and their initial parameters (temperature and moisture) on the danger of recondensation and recommendations to mitigate such threats were made.

42 - 50

Authors: A.V. Doroshenko; K.A. Rzhesik; M.V. Gordienko

The authors note the increasing importance of the evaporative methods of cooling, in particular, air coolers. On the basis of the evaporative coolers of indirect type (Indirect evaporative cooling, IEC) new decisions are worked out for chillers Ch-Rg* and Ch-Rg, in that the preliminary cooling of ambient air comes true in a heat-exchanger before its entering the evaporative cooler of EC, that provides lowering of the cooling limit to the dew point temperature of the ambient air of tр. Also several decisions were offered by the authors for multistage EC (IECg mst.) and, on the basis of the own experimental data, preliminary analysis of their fundamental possibilities was executed. The multichannel surfaces from polymeric materials were used as the nozzles in all types of EC. Air coolers of direct type DEC and Ch-Rg* have as a cooling limit the temperature of ambient air wet thermometer. IEC indirect type coolers and chiller Ch-Rg allow to cool the air flow at unchanging dryness, that is promisingly for the construction of the climatization systems and for the EC different multi-stage decisions design and have as a cooling limit a temperature of ambient air dew point. The comparative analysis of new decisions potential showed that degree of approaching to the cooling limit t** = (t2г - tр1) for the multistage cooler of IECg mst. is t** = 3,50С, at t** = 5,50С for single-stage Ch-Rg. But for chiller Ch-Rg the cost and expenses of power on the organization process are significantly less.

55 - 59

Authors: N.A. Prusenkov

A modern revision of the DBN B.2.6-31:2006 shown in the INTERNET last year (2013), should be comprehensive, providing not only the introduction of innovations, but also clearing errors before-released previously. Scientific and theoretical basis for the design of the IOC secured long experience in operating and it is not necessary to modify it fundamentally. The publication gives examples from the text of this provision requiring corrections and clarifications, or, even, revision and additions: - Invalidity of indications of underestimation of the modern engineering level; - violation of the principle of unity systems measurements, collected by the general document in the general formula (probably intentionally); - backwardness of the restrictions stipulated by DBC, stimulated by observing these requirements principle of the constancy of specific thermal resistance; - appropriateness of the use of fencing structures properties that are excluded from consideration in abovementioned standards (for example - mobility of heat carrier environment)... These and more durable inaccuracies hinder the implementation of modern-governmental ways of regulation of power losses in fencing by compensation of revenues from external sources.

64 - 70

Authors: Yu.M. Symonenko

If there was a "Red List" of endangered chemical elements of the world, helium would definitely go in the top ten of critical substances. Along with silver, zinc and germanium helium is going to practically run out by the end of the twenty-first century. Moreover, the solar gas is the only gaseous element on this list. At the same time, a lot of modern and perspective technologies are impossible without helium. Unique physical and chemical features make it irreplaceable in scientific research, medicine, power engineering, aerospace and defense industries. Helium can be truly considered as an indicator of high technology.

76 - 78

Authors: G.S. Gayvoronskaya; P.P.Yatsuk; I.V. Gannitskiy; Yu.S. Kazak

This article discusses research development of ICT sector in the world. Determining the level of development of a particular technology for a particular country is carried out by evaluation of statistical data on its use by the method of cluster analysis [3,4]. If the value of the technology is known for a set of countries , we can talk about the possibility of classifying them in terms of development of this technology. For this analysis, we used the official data on the number of users of different types of communication in 53 countries for the period from 2000 to 2012 . Data were taken from the site of the International Telecommunication Union [6] Studied data on the number of connections using : fixed wired broadband connection (T1) , fixed telephony (T2) , mobile communications ( T3) Internet ( T4). The result of applying cluster analysis will be the formation of several groups (clusters) of objects that are "similar" on a few selected indicators or integrated indicator.