The paper shows and analyzes circuit solutions for improving the existing schemes of ejector heat-using refrigeration machines, which are used as part of cogeneration plants. One of the promising areas is the use of an aerothermopressor, which implements the effect of thermogasdynamic compression, which is to increase the pressure while reducing the temperature in the evaporation of liquid, which injected into the flow of vapor moving at speed near the sound. To analyze the efficiency of ejector refrigeration machines, the developed calculation model was used, which takes into account the use of an aerothermopressor in the cycles of refrigeration machines with the features of the calculations of cycles and circuits. To select and determine possible circuit solutions, the efficiency of an aerothermopressor for different refrigerants was evaluated and a comparative analysis of the characteristic parameters of the efficiency of an aerothermopressor in the range of cooling temperature differences is 20–100 oC was made. It is possible to increase the efficiency of ejector heat-using refrigeration machines when using an aerothermopressor by providing a temperature difference of 60–100 oC. The analysis showed that the most important are: R717, R134a, R227ea, R1234ze (E), R1234yf (2–4%). It is possible to provide a higher thermal coefficient for ejector heat-using refrigeration machines by using an aerothermopressor in the circuit using the circulation of liquid refrigerant. The corresponding increase in the thermal coefficient is 1.5–2.0%. The use of an aerothermopressor in the scheme with heat recovery allows removing additional overheating of vapor before suctioning into the ejector with a corresponding increase in the thermal coefficient by 4-8%. The analysis shows that the total increase in the thermal coefficient due to the combined use of an aerothermopressor, heat recovery, and recirculation is 10–15% at a base value of 0.30–0.40.

The most common way to increase power and reduce fuel consumption by modern power plants is contact cooling of a gas or air flow by water injection. A promising development of this direction is to use aerothermopressor technologies. The use of heat air, which is compressed by the power plant compressors, accelerates the flow to a speed close to the sound one and almost instantaneous evaporation of injected water (the effect of thermo-gas-dynamic compression). It is important to determine the rational parameters of the organization of thermophysical and hydrodynamic processes when developing such technologies. In this case, one should be taken into account the appropriate development of the flow path design and a special software product. It is necessary to use methods and means to determine the optimal operating parameters of the power plant heat recovery systems. This paper presents a block diagram and an algorithm of a rational methodology for designing an aerothermopressor, which makes it possible to accurately determine the efficiency of using an aerothermopressor as part of a power plant (based on a gas turbine engine) for cooling cycle air, considering the peculiarities of operating modes in the flow path, as well as under various climatic operating conditions. The algorithm of a rational methodology for designing aerothermopressor technologies allows calculating the characteristics of equipment, systems, and circuit design solutions when used as part of a power plant: an electric generator; heat-using refrigerating machines (ejector refrigerating machines, absorption refrigerating machines); turbine generator or steam generator as part of a trigeneration unit or as part of a turbo-compound unit (power plants of marine vessels); recovery boiler of one or two pressures. Modeling the aerothermopressor-cooling system operation makes it possible to reveal the effectiveness of using such a system as part of a power plant and compare it with traditional methods of cooling and humidifying cycle air.

Existing technologies to improve the fuel and energy efficiency of gas turbine plants due to intercooling of the cycle air are analyzed. One of the promising ways for increasing the efficiency of such technologies is using thermogasdynamic compression in the heat recovery processes of secondary energy resources. A feature of this process is the pressure rate increase due to the instant evaporation of a finely dispersed liquid is injected into the air stream which accelerated to the speed of sound. When the pressure of the boiling liquid is increased, the power consumption for compressing the working fluid (cyclic air) is reduced, the efficiency is increased and the consumption of the fuel and energy resources of the gas turbine plant is reduced.The advantages of cooling technology with an aerothermopressor are outlined in the article. The aerothermopressor is a multifunctional jet apparatus, whose work consists in injecting water into the stream of cyclic air when it is compressed in the gas turbine plant compressor. If this apparatus is used for cooling of cycle air, it will be compensate for aerodynamic losses along the air path and it will reduce compression work in the compressor, increase the consumption of the working fluid and, as a result, increase the gas turbine plant power. The basic schemes of the aerothermopressor installation between the stages of low and high pressure compressors are considered. Theoretical thermodynamic cycles of such gas turbine plants are presented and the advantage of using a contact cooler for intercooling of the cyclic air in comparison with surface air coolers for intercooling is defined in this paper.The proposed cooling technology makes it possible using low-potential heat of secondary energy resources of gas turbine plants (heat of cyclic air), the utilization of which by traditional methods is problematic because the temperature of waste heat sources is low.The tasks are determined, the solution of which will ensure the possibility of rational organization of cooling processes in the aerothermopressor, which in turn will allow achieving optimal parameters for increasing the efficiency of the gas turbine plant and reducing the specific fuel consumption in relation to the variable climatic conditions of operation

The efficiency of cooling the scavenge air of the main low-speed engine of the transport vessel during operation in the equatorial tropical latitudes is analyzed. The peculiarity of the tropical climate is the high relative humidity of the air at the same time its high temperatures and temperatures of seawater. The cooling of the scavenge air with an absorption lithium bromide chiller by transforming the scavenge air heat into the cold was investigated. With this, the potentially possible minimum temperature of the cooled air was determined considering the temperature of the cold water (coolant) from the absorption lithium bromide chiller and the temperature differences in the heat exchangers of the intermediate water circuit of cooling. Absorption lithium bromide chillers are characterized by high efficiency of transformation of waste heat into cold - high coefficients of performance. Circuit-design solution of three-stage cooling system of scavenging air of ship's main engine - in high-temperature (cogeneration) stage using the extracted heat of scavenging air to get cold with absorption chiller and traditional stage for cooling scavenge air by seawater and low-temperature cooling stage by absorption chiller. The effect of deeper cooling of the scavenge air was determined in comparison with the cooling of the scavenge air with seawater, taking into account the changing climatic conditions during the route of the vessel. It is shown that due to the high efficiency of heat transformation in absorption chillers (high coefficients of performance 0.7…0.8), there is a significant amount of excess heat of scavenging air over the heat required to cool it to 22 °C, which reaches almost half of the available scavenge air heat on the Shanghai-Singapore-Shanghai route. This reveals the possibility of additional cooling the inlet of the turbocharger of the engine with the achieving almost double fuel economy due to the cooling of all cycle air of the low-speed engine, including the air at the inlet.

The efficiency of cooling the scavenge air of the main low-speed engine of the transport vessel during operation in the equatorial tropical latitudes is analyzed. The peculiarity of the tropical climate is the high relative humidity of the air at the same time its high temperatures and temperatures of seawater. The cooling of the s scavenge air with a refrigerant ejector chiller was investigated by transforming the scavenge air heat into the cold. With this, the potentially possible minimum temperature of the cooled air was determined considering the boiling temperature of the refrigerant and the temperature differences in the heat exchangers of the intermediate water cooling circuit. Refrigerant ejector chiller is used as the most simple and reliable in design. However, the efficiency of converting the heat to cold by ejector chillers is low: their coefficients of performance are approximately 0.3. Circuit-design solution of three-stage cooling system of scavenging air of ship's main engine - in high-temperature (cogeneration) stage using the extracted heat of scavenging air to get cold with ejector chiller and traditional stage for cooling scavenge air by seawater and low-temperature cooling stage by ejector chiller. The effect of deeper cooling of the scavenge air was determined in comparison with the cooling of the scavenge air with seawater, taking into account the changing climatic conditions during the route of the vessel. It is shown that because of the insufficiently high efficiency of transformation of the scavenge air heat by the ejector chiller (low coefficients of performance) the obtained cooling capacity is not sufficient to cool the scavenge air to a potentially possible minimum temperature of 22 °C when operating the ship engine in tropical climates. However, the heat deficit is relatively small and can be covered by the use of additional exhaust gas heat.