Refrigeration engineering and technology

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.