The dissertation deals with issues related to solving the scientific and applied problem of improving the environmental and energy efficiency of marine diesel en-gines and their systems in connection with the constant tightening of international re-quirements. Thermodynamic processes in diesel engines and in refrigeration units of fuel temperature stabilisation systems were chosen as the object of research. Refriger-ation units on ships of various types and purposes are also used in many systems: in hold cooling systems on refrigerated ships, in gas re-liquefaction systems on LNG carriers, in air conditioning systems and in provisions stores on all types of ships.
This work investigates the operating process of a marine diesel engine using ul-tra-low sulphur fuels. Such fuels are recommended for use in marine vessels by the International Maritime Organization to reduce the volume of harmful emissions.
In order to reduce the impact on the greenhouse effect, the paper proposes to use promising mixtures of ozone-friendly and natural refrigerants for the refrigeration unit of the fuel temperature stabilisation system. As shown by the comprehensive eco-logical and thermo-economic analysis performed in this work, the use of new mix-tures in the system for stabilising the fuel temperature of a marine diesel engine will improve the environmental performance of its refrigeration unit and achieve greater energy efficiency of the cycle than when using the components of the mixtures, one of which is a fairly common refrigerant.
To analyze the possibility of efficient use of the studied mixtures as working sub-stances of ship refrigeration systems, the method developed in this thesis was used to obtain models of the state of the mixtures to calculate their thermodynamic properties. To evaluate the accuracy and reliability of the calculation of thermodynamic proper-ties using state models, a detailed comparison of the calculated values of the proper-ties with the experimental data used to develop the models was performed.
On the basis of experimental and additional reference data obtained using the method of the mixture components interaction function, unified state models were developed for calculating the thermodynamic properties of promising R32/R125, R125/R290 and R134a/R290 mixtures. These properties are necessary for the design of refrigerating plants of ship cooling and air conditioning systems when used the re-searching mixtures.
An automated information system has been created to calculate the thermodynam-ic properties of a large number of substances (including the studied refrigerant mix-tures), as well as the operating parameters of refrigeration units based on these sub-stances. Using an automated information system, the thermodynamic behaviour of the mixtures in the state of phase equilibrium was investigated and the azeotropic compo-sitions for each of them were determined. The use of azeotropic mixtures as working substances in refrigeration units of fuel temperature stabilisation systems creates the necessary conditions for their highly efficient operation. The values of the refrigera-tion coefficient, cooling capacity, and effective efficiency of the chiller of the fuel temperature stabilisation system using azeotropic mixtures and their components were calculated. The calculation results showed higher values of the main efficiency pa-rameters when using refrigerant mixtures than when using their components.
An analysis of the ecological and energy efficiency of the refrigerating plant which is a part of the fuel temperature stabilization system of the ship's diesel engine, which runs on fuel with an ultra-low sulfur content, was carried out. As a result of the analysis, a conclusion was made about the prospects of using new mixtures of refrig-erants and their components as working substances of ship refrigerating plants.
Key words: ecological requirements, working process, ultra-low sulfur fuels, fuel temperature stabilization system, marine diesel of transport vessel, refrigerant mix-tures, equation of state, thermodynamic properties, automated system, phase equilib-rium, property tables, perspectives of using.
