2024 - Repozytorium publikacji - Politechnika Gdańska

Pokaż publikacje z roku

Publikacje z roku 2024

Pokaż wszystkie

A stochastic approach for the solution of single and multi – objective optimisation problems of biological processes in sequencing batch reactor
- Tomasz Ujazdowski
- Robert Piotrowski
- Michał Banach
2024 JOURNAL OF PROCESS CONTROL
This paper investigates the impact of implementing single and multi-optimisation solutions on the biological treatment process in a sequencing batch reactor (SBR). The research is based on a case study of the water resource recovery facility (WRRF) in Swarzewo, Northern Poland. The paper introduces the adaptive extremum seeking control (ESC) method for dissolved oxygen (DO) concentration control and places it in a layered control structure. Further, it presents the introduction of an optimisation layer for the structure and parameters of the SBR cycle, through the synthesis of stochastic methods: single-objective optimisation (SOO) using a genetic algorithm (GA) and multi-objective optimisation (MOO) using the NSGA-II algorithm. The results were compared to a classical approach with fixed cycle parameters. The paper shows the advantages of optimising cycle parameters, including the number of phases as well as the DO value, on the process flow. These control structures underwent simulation tests in the MATLAB environment with the Simba package. The biochemical processes occurring in the reactor are based on the Activated Sludge Model No. 2d (ASM2d). The optimising control system demonstrates tangible improvements in operational efficiency and significant reductions in electrical energy consumption, highlighting the effectiveness of the proposed methodologies. © 2017 Elsevier Inc. All rights reserved.
A study of cavitation erosion resistance of an ion nitrided titanium alloy by means of the vibration and rotating disk methods
- V.a. Safonov
- Anna Zykova
- Janusz Steller
- Marek Szkodo
- Grzegorz Gajowiec
- Jarosław Chmiel
- A. Varhoshkov
2024 Pełny tekst Journal of Physics : Conference Series
In this work, a comparative analysis of the cavitation erosion resistance of the Ti– 6.7Al–2.5Mo–1.8Cr–0.5Fe–0.25Si alloy (known as brand VT3-1) before and after lowtemperature ion nitriding is carried out. Two test methods were applied, using vibrative (ASTM G-32) and rotating disk rigs, respectively. The kinetic dependences of the erosive destruction of samples of titanium alloy VT3-1 in the initial state, after ion nitriding and stainless steel AISI 321 were obtained. A study of the microstructure, hardness and surface morphology was carried out. The samples were examined using optical and scanning electron microscopy. The relationship between mass loss and cavitation erosion duration was experimentally determined and analyzed. The erosion rate on a rotating disk stand is much higher than during vibration tests. A large cavitation load gradient provides additional opportunities for analyzing the durability of materials and coatings using this method.
A Study on the Effects of Cold Deformation on CMnSi Steel Structures Utilised in the Shipbuilding Industry
- Van Nhanh Nguyen
- Duong Nam Nguyen
- Janusz Kozak
- Xuan Phuong Nguyen
- Dinh Tuyen Nguyen
2024 Polish Maritime Research
This article analyses the effects of deformation on the structure of CMnSi steel at various deformation levels. After hot forging, the structure of CMnSi steel comprises coarse-sized alpha and pearlite particles. The average grain size of steel after forging was 100 μm. After hot rolling, the grain size gradually decreases, with the average size of the ferrite and pearlite grains measured as 60 μm. After that, CMnSi steel was subjected to cold deformation at levels of 40%, 60%, and 80%. The grain size of the CMnSi steel sample after 80% cold deformation reached level 7, corresponding to about 25 μm. For a deformation level of 40%, the grain size was level 5, corresponding to 40 μm, while a deformation level of 60% produced a grain size of 35 μm, corresponding to level 6. In addition, scanning electron microscopy showed that after 80% deformation, smaller particles with a size of about 5 μm appear inside the parent particles. Moreover, energy-dispersive X-ray spectroscopy analysis revealed the carbide appearance in the form M23C6, with M being a mixture of Fe and Mn. These carbides have a fine size of about 1–2 μm and contribute to the prevention of particle growth during subsequent heat treatments.
A Survey on the Datasets and Algorithms for Satellite Data Applications
- Michał Affek
- Julian Szymanski
2024 IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
This survey compiles insights and describes datasets and algorithms for applications based on remote sensing. The goal of this review is twofold: datasets review for particular groups of tasks and high-level steps of data flow between satellite instruments and end applications from an implementation and development perspective. The article outlines the generalized data processing pipelines, taking into account the variations in data sources and intended use cases. It also provides an overview of the current satellite types, operational constellations, and the capabilities for onboard and ground processing. The review further compares popular datasets based on the specific objectives of their corresponding end applications. The comparison includes AI readiness information for the datasets. Particularly, between others, specification if they contain reproducible data splits or author's defined metrics. A study and explanation of the workflow are performed for the typical and experimental preprocessing pipelines and decision algorithms. These decision-making algorithms include artificial intelligence methods emphasizing deep learning algorithms for computer vision. A basic usage comparison of algorithms is performed for each defined task. In summary, the article presents the data flow from cameras and radars on satellite to end applications. It provides an in-depth analysis of selected scenarios that exemplify diverse approaches to extracting valuable information from data. These representative scenarios were picked to cover typical computational pipelines, for example, object detection or segmentation, and to list distinct approaches for obtaining versatile data-derived information.
A systematic review on cellular responses of Escherichia coli to nonthermal electromagnetic irradiation
- Khadijeh Askaripour
- Arkadiusz Żak
2024 BIOELECTROMAGNETICS
Investigation of Escherichia coli under electromagnetic fields is of significance in human studies owing to its short doubling time and human‐like DNA mechanisms. The present review aims to systematically evaluate the literature to conclude causality between 0 and 300 GHz electromagnetic fields and biological effects in E. coli. To that end, the OHAT methodology and risk of bias tool were employed. Exponentially growing cells exposed for over 30 min at temperatures up to 37C with fluctuations below 1C were included from the Web‐of‐Knowledge, PubMed, or EMF‐Portal databases. Out of 904 records identified, 25 articles satisfied the selection criteria, with four excluded during internal validation. These articles examined cell growth (11 studies), morphology (three studies), and gene regulation (11 studies). Most experiments (85%) in the included studies focused on the extremely low‐frequency (ELF) range, with 60% specifically at 50 Hz. Changes in growth rate were observed in 74% of ELF experiments and 71% of radio frequency (RF) experiments. Additionally, 80% of ELF experiments showed morphology changes, while gene expression changes were seen in 33% (ELF) and 50% (RF) experiments. Due to the limited number of studies, especially in the intermediate frequency and RF ranges, establishing correlations between EMF exposure and biological effects on E. coli is not possible.
A tool for designing water tanks for measuring hydroacoustic transducers
- Roman Salamon
- Jacek Marszal
- Iwona Kochańska
2024 Pełny tekst Vibrations in Physical Systems
Special water tanks are commonly used to measure the parameters of underwater acoustic systems. They must meet specific requirements, the fulfilment of which ensures very small but acceptable measurement errors. These requirements define the size of the tank and its shape as well as the strong attenuation of reflected waves. At the design stage, it is necessary to determine the impact of the tank structure on the measurement errors and to adapt it to the expected measurement methodology. The article presents a mathematical tool for designing such water tanks using the impulse response method. Contrary to the use of this method in architectural design, the presented method is here used to determine the measurement signals emitted by ultrasonic transmitting transducers and received by receiving transducers. The relationships are given between the parameters of the impulse response and the design parameters of the tank and the measurement system, as well as its transfer functions and sample measurement signals.
A total scoring system and software for complex modified GAPI (ComplexMoGAPI) application in the assessment of method greenness
- Fotouh R. Mansour
- Khalid M. Omer
- Justyna Płotka-Wasylka
2024 Pełny tekst Green Analytical Chemistry
Evaluating analytical methods with innovative metrics is essential to ensure the effectiveness of analytical procedures. Various approaches have been proposed to assess the performance of an analytical method and its environmental consequences, as sustainable environment and green chemistry ideology are of high importance nowadays. Considering greenness evaluation of developed analytical procedures, Green Analytical Procedure Index (GAPI), one of these metrics, utilizes five distinct colored pentagons to evaluate the environmental foot- print of the analytical process at different stages. An additional tool named Complementary Green Analytical Procedure Index (ComplexGAPI) was introduced to expand on GAPI by adding additional fields pertaining to the processes performed prior to the analytical procedure itself. Nevertheless, the existing ComplexGAPI lacks a comprehensive scoring system for individual methods, which would allow for even easier comparison of pro- cedures using this tool. In response to queries from ComplexGAPI users, this study introduces a refined tool named ComplexMoGAPI, merging the visual appeal of ComplexGAPI with precise total scores. The accompa- nying software streamlines the application, facilitating quicker and simpler evaluations. This software is avail- able as an open source on bit.ly/ComplexMoGAPI. We believe that, following ComplexGAPI success, this ComplexMoGAPI tool will also gain attention and eventually trust and acceptance from the chemical community.
Absorbing Boundary Conditions Derived Based on Pauli Matrices Algebra
- Tomasz Stefański
- Jacek Gulgowski
- Kosmas L. Tsakmakidis
2024 IEEE Antennas and Wireless Propagation Letters
In this letter, we demonstrate that a set of absorbing boundary conditions (ABCs) for numerical simulations of waves, proposed originally by Engquist and Majda and later generalized by Trefethen and Halpern, can alternatively be derived with the use of Pauli matrices algebra. Hence a novel approach to the derivation of one-way wave equations in electromagnetics is proposed. That is, the classical wave equation can be factorized into two two-dimensional wave equations with first-order time derivatives. Then, using suitable approximations, not only Engquist and Majda ABCs can be obtained, but also generalized ABCs proposed by Trefethen and Halpern, which are applicable to simulations of radiation problems.
Accelerated remyelination and immune modulation by the EBI2 agonist 7α,25-dihydroxycholesterol analogue in the cuprizone model
- Klaudia Konieczna-Wolska
- Fionä Caratis
- Mikołaj Opiełka
- Karol Biernacki
- Krzysztof Urbanowicz
- Joanna Klimaszewska
- Piotr Pobiarzyn
- Oliwier Krajewski
- Sebastian Demkowicz
- Ryszard T. Smoleński
- Bartosz Karaszewski
- Klaus Seuwen
- Aleksandra Rutkowska
2024 BIOMEDICINE & PHARMACOTHERAPY
Research indicates a role for EBI2 receptor in remyelination, demonstrating that its deficiency or antagonism inhibits this process. However, activation of EBI2 with its endogenous ligand, oxysterol 7α,25-dihydroxycholesterol (7α,25OHC), does not enhance remyelination beyond the levels observed in spontaneously remyelinating tissue. We hypothesized that the short half-life of the natural ligand might explain this lack of beneficial effects and tested a synthetic analogue, CF3-7α,25OHC, in the cuprizone model. The data showed that extending the bioavailability of 7α,25OHC is sufficient to accelerate remyelination in vivo. Moreover, the analogue, in contrast to the endogenous ligand, upregulated brain expression of Ebi2 and the synthesis of 15 lipids in the mouse corpus callosum. Mechanistically, the increased concentration of oxysterol likely disrupted its gradient in demyelinated areas of the brain, leading to the dispersion of infiltrating EBI2-expressing immune cells rather than their accumulation in demyelinated regions. Remarkably, the analogue CF3-7α,25OHC markedly decreased the lymphocyte and monocyte counts mimicking the key mechanism of action of some of the most effective disease-modifying therapies for multiple sclerosis. Furthermore, the Cd4+ transcripts in the cerebellum and CD4+ cell number in the corpus callosum were reduced compared to vehicle-treated mice. These findings suggest a mechanism by which EBI2/7α,25OHC signalling modulates the immune response and accelerates remyelination in vivo.
Accessibility to urban green spaces: A critical review of WHO recommendations in the light of tree-covered areas assessment
- Patrycja Przewoźna
- Adam Inglot
- Marcin Mielewczyk
- Krzysztof Mączka
- Piotr Matczak
2024 ECOLOGICAL INDICATORS
Easy accessibility of Urban Green Spaces (UGSs) is essential to the quality of life in urban areas. The World Health Organization (WHO) recommendations focus on spatial access to UGSs, define as accessible those larger than 0.5 ha situated up to 300 m of residential areas, and disregard the social significance of smaller green spaces. This paper assesses the extent to which the WHO recommendations permit the identification of locations for tree-covered UGSs that serve urban residents. The study uses geo-questionnaire to collect data on residents’ perception of the ecosystem services (ESs) provided by trees in both small-sized (<0.5 ha) and larger (≥0.5 ha) UGSs in two Polish cities, Poznań and Gdańsk. Three factors impacting the social perception of UGS accessibility were controlled: (a) distance to trees (influencing reaching it by walk), (b) age, (c) the ESs provided by trees in both sizes of UGSs. The minority, i.e. 26 % of respondents valued trees in the larger UGSs. Regulating ecosystem services appeared significant there (mainly impact on health and well-being) and cultural ecosystem services, such as recreation. Most of the treecovered areas residents’ identified as significant were small-sized UGSs within the median distance of 150 m and were related to trees in residential areas and along the roadsides. Cultural ecosystem service − a sense of intimacy, separating from the neighbors, was specifically valued there. Age does not appear to be a major determinant of social perspectives on trees in UGSs. The results suggest that smallsized tree-covered UGSs are essential to residents and should be included in policies on urban greenery. In addition, the research findings indicate that identifying UGSs that are valuable from residents’ perspectives requires a comprehensive methodological approach. Limiting the assessment of the accessibility of such sites only to analyses based on the criterion of area and distance can offer narrow policy guidelines.
Accuracy of marine gravimetric measurements in terms of geodetic coordinates of land reference benchmark
- Krzysztof Pyrchla
- Kamil Łapiński
- Jakub Szulwic
- Wojciech Jurczak
- Marek Przyborski
- Jerzy Pyrchla
2024 Pełny tekst Eksploatacja i Niezawodność - Maintenance and Reliability
The article presents how the values of (3D) coordinates of land reference points affect the results of gravimetric measurements made from the ship in sea areas. These measurements are the basis for 3D maritime inertial navigation, improving ships' operational safety. The campaign verifying the network absolute point coordinates used as a reference point for relative marine gravity measurements was described. The obtained values were compared with catalogue values. In verification of network points 3D position the satellite data Global Satellite Navigation System (GNSS) and ground supporting systems (GBAS) was used. In this example, the height difference of the land reference point was 0.32 m. As a consequence, the offset budget of the marine campaign was affected in the range of up to 0.35 mGal. The influence on gravity free-air anomaly was not constant over the entire area covered by the campaign.
Accurate Post-processing of Spatially-Separated Antenna Measurements Realized in Non-Anechoic Environments
- Adrian Bekasiewicz
- Vorya Waladi
- Tom Dhaene
- Bartosz Czaplewski
2024
Antenna far-field performance is normally evaluated in expensive laboratories that maintain strict control over the propagation environment. Alternatively, the responses can be measured in non-anechoic conditions and then refined to extract the information on the structure field-related behavior. Here, a framework for correction of antenna measurements performed in non-anechoic test site has been proposed. The method involves automatic synchronization (in time-domain) of spatially separated measurements followed by their combination so as to augment the fraction of the signal that represents the antenna performance while suppressing the interferences. The method has been demonstrated based on six experiments performed in an office room. The performance improvement due to proposed post-processing amounts to 9.4 dB, which is represents up to over 5 dB improvement compared to the state-of-the-art methods.
Activated Tungsten Inert Gas Weld Characteristics of P91 Joint for Advanced Ultra Supercritical Power Plant Applications
- Vishwa Bhanu
- Dariusz Fydrych
- Shailesh M. Pandey
- Ankur Gupta
- Chandan Pandey
2024 JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
Activated Tungsten Inert Gas (A-TIG) welding, a variant of tungsten inert gas (TIG) welding, was used for welding P91. In Generation IV power plants, P91 welds are prone to premature failure due to the presence and formation of brittle phases and creep at high temperatures. When performing A-TIG welding, the flux composition plays a role in the reversal of the Marangoni flow in the weld pool, which ultimately determines the level of penetration achieved. A-TIG gave a complete penetration of 8 mm in the P91 weld. The weldment exhibited non-uniform growth of microstructures with varying grain sizes and precipitates, resulting in variation in mechanical properties. The weld fusion zone (WFZ) had a martensitic structure. The standard flat tensile test specimens were found to fail in the base metal and the fine-grain heat affected zone (FGHAZ) region. The sub-size flat tensile test specimen gave a high strength of 863 ± 10 MPa, failing in the WFZ. The high temperature tensile test specimens had the tensile strength of 512 ± 10 MPa (at 450 °C) and 469 ± 10 MPa (at 450 °C). In both the high temperature tensile test specimens, failure occurred in the base metal region. The impact toughness was recorded at 76 ± 15 Joules due to the presence of untempered martensite in the AW state, and in the PWHT state, the impact toughness increased up to 98 ± 15 Joules. In the AW state, the coarse grain heat affected zone (CGHAZ) region was observed with a maximum microhardness of 450 ± 5 HV and WFZ 460 ± 5 HV. The post-weld heat treatment (PWHT) was successfully performed to temper the martensite and impart some ductility to the weld. The A-TIG weld had sufficient benchmark strength, and the study successfully concluded its aim.
Active Diagnostic Experimentation on Wind Turbine Blades with Vibration Measurements and Analysis
- Zbigniew Korczewski
- Jacek Rudnicki
2024 Pełny tekst Polish Maritime Research
Paper deals with the key operational problems of wind turbosets, especially offshore, where vibrations are generated by rotor blades, as a consequence of erosive wear or icing. The primary causes of the imbalance of wind turbine rotors have been characterised, the observable symptoms of which include various forms of vibrations, transmitted from the turbine wheel to the bearing nodes of the power train components. Their identification was the result of an active diagnostic experiment, which actually entered the aerodynamic-mass imbalance of a turbine rotor into a wind power train, built as a small scale model. The recording of the observed monitoring parameters (vibration, aerodynamic, mechanical and electrical) made it possible to determine a set of symptoms (syndrome) of the deteriorated (entered) dynamic state of the entire wind turboset. This provides the basis for positive verification of the assumed concept and methodology of diagnostic testing, the constructed laboratory station and the measuring equipment used. For this reason, testing continued, taking into account the known and recognisable faults that most often occur during the operation of offshore wind turbosets. Transferring the results of this type of model research to full-size, real objects makes it possible to detect secondary (fatigue) damage to the elements transmitting torque from the wind turbine rotor to the generator early, especially the thrust bearings or gear wheel teeth.
Active Kriging-based conjugate first-order reliability method for highly efficient structural reliability analysis using resample strategy
- Changqi Luo
- Shun-Peng Zhu
- Behrooz Keshtegar
- Wojciech Macek
- Ricardo Branco
- Debiao Meng
2024 COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
Efficient structural reliability analysis method is crucial to solving reliability analysis of complex structural problems. High-computational cost and low-failure probability problems greatly limit the efficiency in structural reliability analysis problems, causing the safety and reliability of the structure to be questioned. In this work, a highly efficient structural reliability analysis method coupling active Kriging algorithm with conjugate first order reliability method (AK-CFORM) is proposed. Specifically, the resample strategy is considered to reduce the number of samples evaluated in each active learning process; the uniform sampling is used to better balance global and local optimal problems; the conjugate map is used to improve the robustness of analytical first order reliability method; and the approximate numerical differential formula is proposed to solve the problems of non-convergence when solving the gradient of the Kriging surrogate model. Finally, three numerical cases and four engineering cases are used to illustrate the effectiveness and robustness of the proposed method. The results show that the proposed AK-CFORM has greater advantages in the number of calling system response and surrogate model with robust and accurate performance.
Active Learning on Ensemble Machine-Learning Model to Retrofit Buildings Under Seismic Mainshock-Aftershock Sequence
- Neda Asgarkhani
- Farzin Kazemi
- Robert Jankowski
2024
This research presents an efficient computational method for retrofitting of buildings by employing an active learning-based ensemble machine learning (AL-Ensemble ML) approach developed in OpenSees, Python and MATLAB. The results of the study shows that the AL-Ensemble ML model provides the most accurate estimations of interstory drift (ID) and residual interstory drift (RID) for steel structures using a dataset of 2-, to 9-story steel structures considering four soil type effects. To prepare the dataset, 3584 incremental dynamic analysis (IDA) were performed on 64 structures. The research employs 6-, and 8-story structures to validate the AL-Ensemble ML model's effectiveness, showing it achieves the highest accuracy among conventional ML models, with an R2 of 98.4%. Specifically, it accurately predicts the RID of floor levels in a 6-story structure with an accuracy exceeding 96.6%. Additionally, the programming code identifies the specific damaged floor level in a building, facilitating targeted local retrofitting instead of retrofitting the entire structure promising a reduction in retrofitting costs while enhancing prediction accuracy.
Activity-based payments: alternative (anonymous) online payment model
- Rafał Leszczyna
2024 Pełny tekst International Journal of Information Security
Electronic payments are the cornerstone of web-based commerce. A steady decrease in cash usage has been observed, while various digital payment technologies are taking over. They process sensitive personal information raising concerns about its potentially illicit usage. Several payment models that confront this challenge have been proposed. They offer varying levels of anonymity and readiness for adoption. The aim of this study was to broaden the portfolio with a solution that assures the highest level of anonymity and is well applicable. An empirical design research study with prototyping and conceptual research with a proposed construct were employed for this purpose. As a result, the Activity-Based Payment (ABP) model was proposed. It introduces a different mode of completing a payment transaction based on performing specific activities on a web location indicated by the payee. The anonymity properties of the solution, as well as its performance and applicability have been evaluated showing its particular suitability to micropayment and small payment scenarios.
Actual and reference evapotranspiration for a natural, temperate zone fen wetland – Upper Biebrza case study
- Malgorzata Kleniewska
- Tomasz Berezowski
- Dorota Mitrowska
- Sylwia Szporak-Wasilewska
- Wojciech Ciezkowski
2024 Pełny tekst Journal of Water and Land Development
Evapotranspiration is the key and predominant component of the water balance in wetlands. Direct evapotranspiration measurements are challenging in wetlands due to their remoteness and high surface water level. This article describes the actual (ETa and reference evapotranspiration (ET0) from a cultivated wet meadow located in the Biebrza National Park – the largest national park in north-east Poland, Central Europe. The data were sourced from a micrometeorological station equipped with an eddy covariance system to measure heat and vapour fluxes and such meteorological elements as radiation balance components, air temperature and humidity. The values of directly measured ETa were presented daily in the context of available energy and ET0. Daily sums of ETa ranged from below 0.2 mm in winter to 6.5 mm in summer. The share of daily sums of ETa in the ET0 usually ranged from 50 to 60%, with extreme values from 10 to 170%. Aside from giving more insight into Biebrza wetlands’ functioning, the actual data produced in this study may be used instead of indirect methods, which were used the most in modelling wetlands areas.
Adapt Your Teacher: Improving Knowledge Distillation for Exemplar-free Continual Learning
- Filip Szatkowski
- Mateusz Pyła
- Marcin Przewięźlikowski
- Sebastian Cygert
- Bartłomiej Twardowski
- Tomasz Trzciński
2024
In this work, we investigate exemplar-free class incremental learning (CIL) with knowledge distillation (KD) as a regularization strategy, aiming to prevent forgetting. KDbased methods are successfully used in CIL, but they often struggle to regularize the model without access to exemplars of the training data from previous tasks. Our analysis reveals that this issue originates from substantial representation shifts in the teacher network when dealing with outof-distribution data. This causes large errors in the KD loss component, leading to performance degradation in CIL models. Inspired by recent test-time adaptation methods, we introduce Teacher Adaptation (TA), a method that concurrently updates the teacher and the main models during incremental training. Our method seamlessly integrates with KD-based CIL approaches and allows for consistent enhancement of their performance across multiple exemplar-free CIL benchmarks. The source code for our method is available at https://github.com/fszatkowski/cl-teacher-adaptation.
Adaptable management for cooling cyclic air in ship power plants by heat conversion – Part 1: Downsizing strategy for cogeneration plants
- Roman Radchenko
- Andrii Radchenko
- Dariusz Mikielewicz
- Mykola Radchenko
- Anatoliy Pavlenko
- Andrii Andreev
2024 ENERGY
The ship power plants (SPP) are generally based on Diesel engines. Their fuel efficiency is gradually sensible to cyclic air temperatures and drops with their rise. A sustainable performance of ship engines with high fuel efficiency is possible by cooling intake and charge air as two objects in waste heat conversion chillers. The peculiarities of marine engine application are associated with constrained space of machine room. Whereas, the chiller’s downsizing leads to inevitable lack of their cooling capacity and incomplete cooling air which results in reduction of fuel saving. The research objective is to develop the heat conversion management adaptable to balanced downsizing and fuel saving strategies due to flexible heat distribution between the chillers of different efficiencies (COP) in response to current thermal loads on engine cyclic air cooling system along the ship routes which enables to foresee a sustainable thermally stabilized and fuel saving operation of SPP. For the first time, such conflicting challenges are satisfied by flexible heat distribution between different chillers in response to intake and charge air cooling needs. The unique of such approach lies in unloading the high efficient but cumbersome chiller (absorption with COP about 0.7 as example) to boost the less efficient but easy to place in machine room ejector chiller (COP of about 0.2). The method of flexible heat distribution to minimize chiller sizes as constraints is realized in methodology based on step-by-step comparing the gap between heat demand and production to minimize shortage in fuel reduction simultaneously. It has been proved that cooling engine air by compact but less efficient ejector chiller (ECh) and high effective but cumbersome lithium bromide absorption chiller (ACh) of reduced capacity and sizes by about 30% accordingly provides a specific fuel consumption reduced by about 3%. The loss of route fuel saving by about 10% is considered as the "cost" for downsizing. These findings have been verified by the calculation results on current and summarized values of the cooling capacities lack, caused by the chiller’s downsizing, and fuel saving along the ship route. The novel strategy of heat conversion by combined chillers is especially useful for upgrading the existing engine air cooling system to implement it into the ship machine room.