Issue 4 (150)
Section 1. Refrigeration engineering
Yu. M. Symonenko
ENERGY SAVING TECHNOLOGIES IN INSTALLATIONS FOR HIGH PURITY NEON AND HELIUM PRODUCING
Classical technology of neon-helium concentrate is considered. The necessity to reduce the specif- ic energy consumption for the light inert gases is substantiated. The reserves of reducing the oper- ating costs in the processing stream stripping are identified. It was proposed to include a mem- brane module in the scheme, wherein neon stream is separated and simultaneously the mixture is enriched with helium. Cost effectiveness of helium extraction technology is enhanced by increasing the duration of cryogenic adsorbers cycle and reducing the number of compressors.
Key words: Neon – Helium – Separator – The distillation column – Compressor – Adsorber – Membrane module.
NEW STEP IN THE DEVELOPMENT OF EXERGY ANALYSIS
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 ob- tained 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 or- der 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.
Key words: Exergetic analysis – Exergy destruction – Advanced exergetic analysis
EQUATIONS FOR REFRIGERANTS R32 AND R125 VISCOSITY CALCULATION
Equations for alternative refrigerants R32and R125 viscosity calculation expressed in terms of independent variables, such as temperature and density are worked out. Equation coefficients are determined by the least square technique according to the experimental data. The equations de- scribe the viscosity at temperatures ranging from 232 to 423 K at a pressure up to 9.8 MPa for R32 and from 230 to 423 K at a pressure up to 10.1 MPa for R125. The composed equations accu- racy is quite acceptable for engineering calculations.
Key words: Refrigerants – R32 – R125 – Viscosity – Equations
A.V. Ovsyannik, E.N. Volkova, T.S. Naumova, V.G. Yakimchenko
THEORETICAL AND EXPERIMENTAL STUDY OF HEAT TRANSFER PROCESSES AT THE DEVELOPED NUCLEATE BOILING OF MIXED OZONE-SAFE REFRIGERANTS ON A SMOOTH SURFACES
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 pro- cess, security settings, and other factors affecting the intensity of heat transfer are established.
Key words: Heat exchange while boiling – Ozone-safe refrigerants – Heat exchange intensity – Thermolysis coefficient – Evaporator – Heat exchanger.
Section 2. Power engineering and energy saving
A. Dimitrov, O. Yakovleva, M. Khmelniuk
POWER CRISIS OR THE FUTURE OF ALTERNATIVE POWER ENGINEERING?
The paper addresses the most acute issues of present-day power engineering prospects. Nowadays the interrelation between global economic crisis and power engineering is en- tirely justified. Reserves of hydrocarbon fuels in the world are depleted, and their prices are rising every year. The investments of the developed countries governments into the re- newable power are increasing. However, is it able to change the actual situation in the world and to help the global economy to overcome the crisis? But is it enough for this pur- pose the achievements of up-to-date scientific and technical progress?
Key words: energy crisis – global power security – wind power – solar power – the revolu- tionary power technologies – the economic feasibility
V.V. Klуmenko, M.V. Bosiy, V.P. Parafiynyk, S.О. Prylypko
GAS TURBINE DRIVE WITH A FUEL GAS GASHYDRATE BOOSTER DEVICE
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 prin- ciple 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.
Key words: Gas hydrates – Natural gas – Formation of gas hydrates – Melting – Hydrates for- mation heat – Gas turbine drive – Thermotransformer
Section 3. Refrigerating and accompanying technologies
А.V. Melnyk, V.P. Zhelezny
MEASUREMENT AND CORRELATION OF FLOW BOILING HEAT TRANSFER OF R600a/COMPRESSOR OIL SOLUTION INSIDE A HORIZONTAL SMOOTH TUBE
Experimental results of local heat transfer coefficients for the boiling of real working fluids (solutions of R600a with mineral naphthenic oil ISO VG 15) in smooth tube with small diameter (5.4 mm) are presented. The tests were carried out for the inlet pressure in the range from 71.1 kPa to 77.9 kPa, heat flux was 3800 W/m2, and mass velocity of working fluid was from 14.75 to 18.36 kg/(m2s). The quantitative estimation in reduction of heat transfer coefficient of the wetted surface in evaporator at high oil concentration in the mixture is made. The influence of mass velocities of the working fluid on the values of the local heat transfer coefficients are analyzed. Based on the results obtained it was observed that increasing mass velocity leads to increase the local heat transfer coefficient of RWF both on side of wetted perimeter and vapor phase. The equation for the modeling of the local heat transfer coefficient for boiling of isobutane/compressor oil solution flow in the pipe is suggested.
Key words: Heat transfer coefficient – Real work fluid –Boiling – Isobutan – Refrigerant/oil solution – Vapor quality – Concentration.
V.Y. Labay, D.I. Harasym
RESEARCH OF EXERGY EFFICIENCY OF AIR CONDITIONING SYSTEMS FOR CLEANROOMS
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 innova- tion thermodynamics. Classic apparatus of this science is often insufficient to solve new tasks; it is neces- sary 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 ex- ergetic output-input ratio for chosen air conditioning system е on temperature difference between the in- side 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 economi- cal variant of exploitation of chosen air conditioning system.
Key words: Exergy balance Air conditioning systems Cleanrooms Exergy efficiency
E.A. Osadchuk , A.S. Titlov, S.Yu. Mazurenko
DETERMINATION OF POWER EFFICIENT OPERATING CONDITIONS OF ABSORPTION WATER-AMMONIA REFRIGERATING MACHINE IN THE SYSTEMS FOR OBTAINING WATER FROM ATMOSPHERIC AIR
The prospects for the use of heat-utilizing refrigerating machines in the systems for obtaining water from the atmospheric air are shown. The power efficient (on the heat coefficient maximum numerical value) operating modes of absorption water-ammonia refrigeration machine with regenerative heat exchanger of solutions depending on the temperature of the cooling medium, cooling object temperature, and heating source temperature have been determined. The results are presented as analytical and graphical dependencies.
Key words: water-ammonia absorption refrigerating machine – power efficiency – heat coefficient – the effect of operating conditions.
Section 4. Automatic, computer and telecommunication technologies
A. Gurskiy, V. Denisenko, A. Goncharenko
DEFICIENCY ON THE RATIO PARAMETERS IN A CONTROL SYSTEM AS A PARAME- TER OF TURBO COMPRESSOR PLANT FUNCTIONING
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.
Key words: Centrifugal compressor – Refrigeration unit – Turbo compressor system – Coordinating management – Power Efficiency – Indirect indicator of operation – Anti-Surge Protection
N. A. Knyazeva, І.В. Gryshchenko, S.V. Shestopalov
METHOD OF TELECOMMUNICATION NETWORK SURVIVABILITY BASED ON THE NETWORK RESOURCES REDISTRIBUTION
The article presents the indicators and parameters characterizing the network survivability.The presented method of ensuring the survivability of the telecommunication network based on the TCS network reallocation of resources to service the flows of requirements in the event of adverse effects allows you to: - perform network performance evaluation based on the proposed measure; - to identify "bottlenecks" for the possibility of network backup solution. The proposed method can be used in the design phase of TCS to evaluate your network when you change the topology.
Key words: Telecommunication network – Vitality – Performance-criteria – Redundancy – Host – Bandwidth – Total Capacity