MODEL OF THE CASCADE THERMOELECTRIC COOLING DEVICES IN THE MODE OF THE LARGEST ENERGY EFFICIENCY

4 and dimensions parameters, but as well an increase in the dynamic and strength indicators for the systems that provide for the thermal modes of thermally loaded elements [1]. A base method for improving the coolers energy effectiveness is an increase in thermoelectric effectiveness of the source materials for thermoelements [2, 3], development of new thermoelectric materials for the promising thin-film modules [4, 5]. A considerable increase in the thermoelectric effectiveness of materials can be achieved by new technologies for creating the thermoelectric materials for coolers and generators [6, 7]. Modern approaches based on the nano-technologies principles [8] allow multi-fold increase in thermoelectric effectiveness through changes in electrical resistance and heat losses by thermoelements, as well as via control of magnetic field [9, 10]. At the same time, any changes in the design of cooler, including the application of new materials that fulfill not only the function of converting electrical energy into cold but also carry mechanical load in the volumetric coolers, lead to changes in the reliability indicators of the device [11, 12]. With an increase in thermoelectric effectiveness, the temperature gradients grow, the adhesive properties of the base layer-thermoelement connection deteriorate, splitting of the contact occurs [13]. A mode of the largest energy effec-


Viktor Gorbov, Denis Solomonuk
The purpose of the conducted research was to develop a method for determining parameters of GTE regenerator, which would ensure at the initial stages of designing a minimum mass of the heat exchanger with the assigned values of efficiency.
We obtained dependences that establish relationships between the regenerator and the GTE, which allow analyzing the influence of effectiveness and pressure losses in regenerator on the efficiency of GTE and the mass of the regenerator.
Relationship between parameters of the regenerator and performance efficiency of regenerative GTE was described by functional dependence, where energy parameters of the regenerator are collected in a single complex. It was established that the magnitude of effectiveness of the regenerator is associated with efficiency by inversely proportional function, and pressure losses -by linear function. Effectiveness of the regenerator is associated with the mass of the heat exchanger and the geometry of heat exchange surface by exponential dependence, and relative pressure losses -by algebraic irrational function.
Based on these dependences, the algorithm for selecting rational energy and geometrical parameters of regenera-ABSTRACT AND REFERENCES ENERGY-SAVING TECHNOLOGIES AND EQUIPMENT tors of GTE was developed. It was found that by selecting rational values of effectiveness of regenerator and pressure losses, it is possible to provide for a significant decrease in mass of the regenerator with a constant value of performance efficiency of GTE.
The obtained results of calculations of regenerators of GTE with different structural solutions allow a designer engineer to choose rational values of effectiveness of the regenerator, pressure losses, and initial gas temperature. Comparison of complex regenerative GTE by the mass of regenerator at constant values of performance efficiency was conducted. Based on the analysis of results of calculations, the stage dependence of specific mass of regenerator on the assigned increase in performance efficiency of regenerative GTE was obtained, which gives the possibility to estimate the mass of tubular regenerator at the initial stages of designing.
Implementation of the obtained results into the practice of designing regenerative GTE will make it possible to ensure the choice of their rational parameters and to decrease the time of designing.
Keywords: gas turbine engine, regenerator, performance efficiency, mass of regenerator, effectiveness of regenerator. We developed a thermoeconomic model of refrigeration plant that works by the supercritical CO 2 cycle as refrigerating medium. The model is built for the plant of the "air -air" type and makes it possible at the optimization of design and the selection of economical operating modes to simultaneously consider both thermodynamic and economic parameters. Resulting expenses for the creation and operation of the system over the projected life cycle were accepted as objective function for analysis of the model. The minimum of resulting expenses corresponds to the optimum system characteristics while maintaining amount and quality of produced cold. Development of the model allowed us to represent objective function in the form of expanded analytical expressions, which consider interrelation between all optimizing parameters of the system.

References
One of the benefits of the method consists in the fact that the obtained unique analytical solution in the form of a system of equations of partial derivatives from objective function of the resulting expenses is applicable for the thermoeconomic optimization of regime parameters of operation of any refrigeration system that works according to the examined scheme and with a similar type of equipment.
Numerical solution of the thermoeconomic optimization problem of refrigeration plant of the "air -air" type (conditioner), with CO 2 as refrigerant, that works in the supercritical region made it possible to find optimum parameters of the system, which provide for the conditions of reaching minimum level of the resulting expenses at different values of tariffs for electric power. We examined effect of the value of tariff for electric power on the character of optimization of the system.
An application of this technique in practice should contribute to the reduction in financial costs for the creation and operation of conditioners that work on CO 2 , to an increase in their competitivness compared with traditional freon systems and contribute to the creation of conditions for their large-scale implementation in Ukraine. Keywords: thermoeconomic model, supercritical cycle, exergy, resulting expenses.

Yurij Shakhov
A variant of modernization is examined of the groundbased system for filling and thermostating by liquid hydrogen of fuel tank of superheavy carrier rocket (CR) "Energy" by using, instead of traditional surface heat exchangers, a jet liquid cooler.
The filling systems that are in operation at present imply the filling of CR tanks with cryogenic components in the boiling state, which limits the period when a rocket is positioned in the launching pad. But the system that was created in the USSR way back in 1987 made it possible to fill the CR "Energy" fuel tanks with the components of rocket propellant in the supercooled state with subsequent thermostating of tanks. Filling the CR tanks with components in the supercooled state with heightened density provided for an increase in the mass of payload by 5 % and allowed prolonging the period, which would rather be used for eliminating the malfunctions in preparing CR for launch, without returning the components to the filling tanks. They used as heat exchange devices the heat exchanger-recuperators of the "boiling bath" type. In this case, the semiclosed scheme of the cryogenic component circulation was implemented.
Using a compact jet liquid cooler as the heat exchange device makes it possible to eliminate bulky heat exchangers, as well as simplify the system through transition to the closed scheme of liquid hydrogen circulation while thermostating the CR fuel tank. Thus, the cryo-component saving is provided for in the process of cooling the structure elements in preparing for the filling.
The procedure for calculating the process of thermostating a fuel tank based on the jet liquid cooler was developed for solving the task of modernization of the filling and thermostating system, which allowed us to calculate attainable parameters of the thermostating system and to determine the range of system working ability. The outlet of external heat flows with power to 1 MW is ensured at pressure at the JCL nozzle exit section 10-30 kPa and temperature of "hot" parahydrogen removal from the tank 18-20 K. In particular, the 73 % increase in the operation period of the system during standard system filling with liquid hydrogen or the savings in liquid hydrogen at the estimated time of CR launch might be regarded as the result of using the modernized filling and thermostating system.
The technical solutions proposed may be applied when designing new and modernizing those existing systems of storage, cooling and filling with liquid hydrogen of the carrier rockets fuel tanks, including promising objects of heavy and superheavy CRs: SLS and Falkon Heavy (USA), CZ-5 and CZ-9 (C.P.R), Angara 5V (Russian Federation).

Mykhailo Babych, Svetlana Korobka, Ruslan Skrynkovskyy, Serhiy Korobka, Roman Krygul
A new design of a solar dryer for drying fruits is proposed, which includes the use of a flat mirror concentrator to enhance the flow of slant morning and evening sunlight, and a thermal accumulator based on pebble for accumulating over night time the excess heat from the reserve source of energy. This makes it possible to increase economic efficiency of the drying process by 20 %, to reduce energy consumption by 15 %, specific energy consumption by 10 %, direct operating costs by 5 %, electricity consumption by 3,4 kW•h, or 12384 kJ of thermal energy, by using solar energy.
We improved a technique of the substantiation of economic efficiency of the developed solar dryer, the basis of which is a simplified mechanism for calculating direct operating costs, economic effect and payback period of the machine depending on the fluctuation of prices for electricity and dried products, linked to a specific territory of the location of a personal peasant farm.
The results that were obtained can be used when developing and improving technical means of drying fruits, to improve technological, energy, biological and economic efficiency of the process.

Viola Vambol
The present paper describes the results of a numerical integration of the process of cooling gas during thermal recycling of waste. The physical model of such cooling is based on injecting the cooling liquid by centrifugal nozzles. The research object is gas-dynamic interphase interactions in the evaporative heat exchanger. The purpose of the research is to improve the ecological safety of thermal recycling of waste by preventing the formation of highly toxic substances in the generated gas. The mathematical models of the gas and dispersed phases are developed and the mathematical description of the interphase interactions in the heat exchanger is provided on the basis of laws of conserving the weight and the impulse amount in an environment that is inhomogeneous in terms of the composition and phases and includes the generated gas, drops of water, and steam. The mathematical formulation of the conservation laws for viscous gas (steam) is achieved through the Navier-Stokes equations; for drops, it is given as an equation of the balance of forces that affect the drop and equalize the inertia force and the resultant forces of gravity and aerodynamic resistance. The studied computational area covers a space fragment bounded by the walls of the heat exchanger. It has been scientifically proved that such technological equipment can be used to provide a sharp cooling of flue gases. The mode of fast cooling prevents the creation of temperature conditions that would facilitate dioxins formation, and thus it increases ecological safety.
Keywords: wastes utilization, ecological safety, dioxins content reduction, mathematical modeling of gas dynamic processes.