Yalama V.V. Energy Efficiency improvement of marine refrigeration systems. Qualification scientific work on the rights of manuscript.
Dissertation for the degree of Doctor of Philosophy in the specialty 142 "Energy Machine Building". Odesa National University of Technology, Odesa, 2023.
The dissertation is dedicated to the study of the marine refrigeration system and the investigation of refrigerants with the aim of enhancing the energy efficiency of the marine refrigeration plant and reducing its environmental impact. Based on scientific works that present results of theoretical and practical research, energy (thermodynamic in particular) and exergy analyses are conducted. Based on scientific works presenting the results of theoretical and practical research in the field of energy analysis, including thermodynamic analysis, and exergy analysis, the utilization of the process mining through conceptual design, employing modeling techniques such as Petri Nets, Business Process Modeling and Notations, enabled the analysis of the marine refrigeration system. The modeling process involved the analysis of the modernization of the refrigeration unit, specifically the transition of the system to environmentally safe refrigerants. Furthermore, the modeling of the cold chain, as a component of a domain-oriented big data integration platform, was conducted, extending to a decentralized IT-integrated platform for the cold chain.
The research methods employed in addressing the specified tasks included energy management and audit for the refrigeration system of a refrigerated vessel older than 20 years, as well as energy (particularly thermodynamic) analysis of the marine refrigeration system. Exergy analysis of the marine refrigeration system was also conducted. The study involved the application of the capabilities driven design methodology, conceptual design, and process mining of refrigeration sector processes using Petri Nets and BPMN languages.
The new scientific results of the work are:
The following tasks were accomplished:
An energy audit of the refrigeration system of a refrigerated vessels with a gross tonnage of 4000, flagged in Poland, was conducted. The energy potential and environmental impact potential were identified.
Recommendations for managing the energy efficiency of the refrigerated vessel were proposed.
Interdisciplinary connections, regulatory framework, and regulations regarding the environmental impact of refrigerated vessel systems were considered. Recommendations were provided for tracking relevant regulations and timely implementation, affecting the modification of existing refrigerated vessels and their operational systems.
Energy (thermodynamic in particular) and exergetic analyses of the marine refrigeration system were conducted, leading to increased energy efficiency and reduced environmental impact.
Two refrigeration systems were proposed for the energy efficiency improvement program:
Marine Cascade Refrigeration System (SCRS) R290/R744:
Expected to increase the efficiency of the marine refrigeration system by 20%.
Reduces environmental impact through the use of natural refrigerants (R290/R744).
Capital costs amount to 201,213 euros.
Two-stage cooling system R717:
Predicted to further increase efficiency to 26%.
Minimizes environmental impact by using ammonia (R717) with GWP = 0.
From a capital cost perspective, the two-stage compression refrigeration system with R717 requires 26% less investment compared to the cascade system.
Recommendation: The choice between the two systems should involve a comprehensive analysis, considering operational costs, maintenance, and long-term benefits. This approach ensures an informed decision that aligns with the specific needs and constraints of the marine refrigeration system. The analysis emphasizes the importance of balancing these factors to determine the most desirable option for the client.
The practical significance of the work is as follows:
Recommendations have been provided for practical implementation in real-time for the maritime sector of refrigerated transport. The assessment of reliability and justification of conclusions involves a comprehensive evaluation of these factors, considering the specific context and requirements of the analysis. An interdisciplinary approach has been employed, involving relevant stakeholders in the assessment process.
