Department of Mechanical engineering

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Author: search.filters.author.Dasgupta, Mani SankarHas files: No

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    Using MCDM techniques for talent identification and management in sports
    (Springer, 2025-03) Dasgupta, Mani Sankar
    Talent identification in sports is a process of identifying individuals with the potential to excel in a particular sport or athletic activity. It entails evaluating a range of psychological, technical, tactical, and physical characteristics in order to pinpoint those who have what is needed to excel in a given sport. Talent management involves strategic management, nurturing already existing talent, and providing support to optimize performance with a vision for long-term success. MCDM Techniques provide a solid framework for determining the best solution to a decision problem taking into account the alternatives and free of any bias. In this paper, we explore the use of MCDM techniques for Talent Identification and Management with a special focus on football. We compiled data of five different players from Europe’s Top 5 leagues using WhoScored and applied AHP and TOPSIS methods to rank and order attackers, defenders, and midfielders on multiple facets of their game. AHP helps to establish a structured and objective framework for determining the criteria and sub-criteria. TOPSIS is then used to rank these players on the basis of these criteria, thus providing valuable insights to clubs for talent identification and player selection in football. With sophisticated football strategies, and with an increasing number of players to pick from, it is becoming harder to distinguish them based on numbers. This study presents a feasible solution to address the issue by objectively evaluating all criteria in a scientific manner, in order to select the most qualified individuals.
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    Performance analysis of an R744 supermarket refrigeration system integrated with an organic rankine cycle
    (MDPI, 2023-11) Dasgupta, Mani Sankar
    The energy and economic performance of a transcritical R744 booster supermarket refrigeration system with and without parallel compression and integrated with an organic Rankine cycle (ORC) was investigated. The results obtained were compared with those of a transcritical R744 booster supermarket refrigeration system with and without parallel compression and those of a conventional R404A direct expansion (DX) system. Nine different locations, namely Copenhagen (Denmark), Paris (France), Athens (Greece), New Delhi (India), Phoenix and Miami (US), Madrid (Spain), Bangkok (Thailand) and Riyadh (Saudi Arabia), were considered. It was discovered that the ORC is effective only at ambient temperatures higher than 27 °C when operating without parallel compression and 28 °C when operating with parallel compression. By using the heat recovered from the gas cooler to fuel the ORC, the latter was found to be capable of covering between 4% and 24% of the electricity demand of the R744 system in warm and hot climates (without parallel compression). The simple payback period of the additional investment associated with the ORC was found to be between 1.4 and 2.5 years in warm climate locations, while the same was found to be less than about 0.5 years in locations experiencing hot climatic conditions.
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    Investigation of economizer with screw compressor to provide subcooling and enhance cop in various natural refrigerant-based cascade freezer
    (Springer, 2024-09) Dasgupta, Mani Sankar
    This study examines two configurations of a cascade refrigeration system using natural refrigerants-R744 in the low-temperature circuit (LTC) and one from this list of R717, R290, R1270, or R600a in the high-temperature circuit (HTC). The motivation behind the design of the two configurations is the subcooling provided by the internal heat exchanger (IHX) and economizer for the natural refrigerant combinations, which is the novelty of the work as well. Both configurations have a single low-temperature evaporator at − 45 °C and operate in a warm ambient of 45 °C. One of the configurations has two IHXs, one in the LTC and the other in the HTC and a desuperheater at the LTC compressor exit and is termed as IDI. The second configuration has an economizer in the HTC and an IHX in the LTC along with a desuperheater at the compressor exit and is termed as IDE. The configurations are compared in terms of energetic and exergetic performance. Among the configurations, the overall COP is found to be the maximum for the IDE system for all refrigerant pairs while R744/R600a outperforms others for both IDI and IDE configurations. The highest overall COP for R744/R600a is 1.21, while it is 1.29 for the IDE exhibiting a 6.6% improvement.
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    Investigation on temperature heterogeneity for angled placing of crates in a cold storage, during precooling
    (Springer, 2025-05) Dasgupta, Mani Sankar
    Precooling conditions in cold storage are essential for preserving horticultural produce and reducing food and moisture loss. Inside a cold storage, the chilling rate and temperature heterogeneity are determined by the airflow. The majority-aligned stacking of produce in containers does not aid air mixing. This research examines how a minor angle between the placement of crates and the predominant air flow direction influences temperature heterogeneity and air velocity. A numerical model is developed to analyze the heat transfer and air flow distribution within cold storage, and it is validated using an experimental study with a normalized root mean square error of 4.57%. The validated model is used to investigate the impact of angular placement of containers and their potential benefits. As the angle of an inclination increases, the region of bypassing air decreases considerably, and the air remains in contact with the crates for a longer period. The monitored temperature distribution within the cold storage indicates that at 15° angle, the temperatures of the crates are approximately 9.89% lower than with a conventionally aligned crate arrangement. Calculations of temperature heterogeneity reveal that containers arranged at 15° were less susceptible to temperature heterogeneity. This research will help cold storage proprietors reduce the pull-down temperature and extend the shelf life of perishable goods.
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    Modelling of an onboard R290 refrigerated sea water (RSW) system for ice production on small fishing vessels in India
    (NTNU, 2024) Dasgupta, Mani Sankar
    India is one of the world's leading fish exporting nations. The fishing sector is expected to grow and already has a large economic and social impact. It is currently dominated by small fishing boats, which use ice to cool the catch. The ice is bought and loaded from the harbour. Catches vary in size and timing, which can result in either unused quantities of ice being carried or insufficient cooling of the catch, resulting in reduced fish quality and increased waste. Therefore, an on-board refrigeration system using R290 (propane) is proposed to produce ice from seawater in the form of ice blocks. A model was created using Modelica to investigate the performance of the system during a typical 15-20-day cruise. The results showed that the on-board refrigeration system can provide the required amount of ice on demand. This reduces quality degradation, fuel consumption, and, therefore, emissions.
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    Performance analysis of an active on-board refrigeration system using propane for improved fish preservation in small fishing boats
    (International Institute of Refrigeration, 2024) Dasgupta, Mani Sankar
    With a seafood production of 16.25 million metric tonnes in fiscal year 2022-23, India secures third rank globally in seafood production. To ensure the nation's food security and improve export earnings, it is critical to prioritize the preservation of seafood quality, and refrigeration plays an important role. This paper investigates the potential of an on-board refrigeration system powered by a diesel engine and utilizing propane to enhance seafood preservation in small fishing boats prevalent in the Indian seafood industry. The study analyses the economic, environmental, energy, and societal impacts of adopting this refrigeration system compared to conventional preservation methods. The hypothesis is that the refrigeration system will reduce losses and waste of fish/seafood harvest caused by inefficient cooling in traditional preservation methods. The study focuses on the small 60 feet trawlers, operated in the coastal area of Gujarat, India, and the field data are collected to carry out the study.
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    Performance analysis of an ejector based CO2 transcritical refrigeration system with integrated mechanical subcooling for dairy application
    (AIP, 2024-01) Dasgupta, Mani Sankar
    Refrigeration system plays a crucial role in the dairy sector to preserve quality and prevent spoilage of milk. This sector also have enormous heating requirement for various processes such as pasteurization and heating of water for cleaning. The carbon dioxide (CO2) based refrigeration system is perceived to be an excellent choice for dairy application since it can simultaneously meet the cooling and heating demand. In the present study, a novel ejector based CO2 transcritical refrigeration system with integrated mechanical subcooling (IMS) is proposed for dairy applications. With IMS, the heating capacity of the refrigeration system is improved since the heat removed for subcooling can also be rejected into the heat recovery unit. The proposed system chills milk to 4 °C and simultaneously supply heat to water that can support various heating requirements. A parametric analysis of the proposed system is carried out and the results are analysed to comprehend the effect of ambient temperature, gas cooler pressure, effectiveness of the heat recovery heat exchanger and degree of subcooling on various performance parameters. It was found that the proposed system could heat water up to 80 °C and achieve an overall coefficient of performance of 4.15 at an ambient temperature of 40 °C. The study concludes that the proposed system is an energy efficient and clean alternative to conventional refrigeration and heating systems.
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    Study on various hot-gas defrosting configurations for CO2-NH3 cascade deep freezer
    (Springer, 2024) Dasgupta, Mani Sankar
    Four hot-gas bypass defrosting configurations for CO2-NH3 cascade blast freezer for application in fish processing firm are numerically investigated. Due to the high moisture content of fish, defrosting is necessary after every 4 to 5 h of batch operation. A thermodynamic model for the cascade system and defrosting was developed to study various defrosting configurations formulated by rearranging the existing compressor to operate as a defrosting compressor and with the addition of an external defrosting compressor. From the simulation findings, it can be summarized that the conventional hot-gas bypass defrosting without defrost compressor is suitable for a high-capacity cascade refrigeration system with more than three evaporators. For low cooling capacity refrigeration systems, a defrosting compressor is necessary to elevate the temperature above the cascade condensing temperature. A dedicated defrosting compressor with a power consumption of 3.1 kW and a modified refrigeration/defrosting compressor with a power consumption of 6.8 kW can deliver 33.3 kW of heating at a temperature of +10 °C (45 bar). Incorporating a desuperheater between the main and defrosting compressors reduces compressor temperature and maintains the lubricating oil stability, without change in defrosting energy consumption and less exergy loss. The defrosting efficiency is obtained in the range of 39.7–42% which is in agreement with published literature.
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    Energy, environmental, and economic analysis of novel R744/R290 cascade refrigeration systems designed for warm ambient conditions utilizing ejector
    (Elsevier, 2024-08) Dasgupta, Mani Sankar
    There is a growing global awareness about the need to reduce total carbon equivalent emissions and other environmental problems caused due to synthetic refrigerants. The study utilizes cascade refrigeration systems (CRS) with R744 in the low-temperature circuit (LTC) and R290 in the high-temperature circuit (HTC). Two evaporators are present in the LTC; one is direct expansion (DX) type at −40 °C with a cooling load of 70 kW, and other is gravity-fed evaporator at −25 °C with 60 kW cooling load. The study aims to enhance the performance and economic and environmental impact of CRS by incorporating parallel compression (PC) in LTC, a gravity-fed evaporator, and an ejector in HTC. The performance is compared to a baseline CRS system using a flash-gas bypass arrangement (FGB) in the LTC, bypassing generated flash gas to compressor suction. PC in LTC removes flash gas from receiver pressure to cascade condenser pressure in the first suggested CRS. While the second proposed CRS (PCEJ) employs an ejector in HTC over and above PC in LTC. The CRSs demonstrate significant higher COP of 1.43, 1.58 and 1.65, leading to an improvement upto 62.4 %, 79 %, and 86 % over the reference HFC-404A system at 45 °C ambient temperature. SEER analysis also establishes higher year-round efficiency compared to reference HFC-404A by 22 %, 36 %, and 44 %. The total TEWI of FGB, PC, and PCEJ is 43.1 %, 53.2 %, and 53.5 % lower compared to the reference system, indicating substantial potential for lowering global warming when implemented. Economic analysis brings out relative cost comparisons under various measures.
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    Mitigating temperature heterogeneity in cold storage: a numerical investigation using a cassette fan coil unit for air flow distribution
    (IOP, 2024) Dasgupta, Mani Sankar
    Inadequate storage conditions for agricultural harvests can result in significant economic losses. Cold storage plays a crucial role in preserving horticultural produce, where proper airflow distribution is essential for maintaining freshness. Ceiling-mounted Fan Coil Units (CM-FCUs), commonly used in cold storages, may lead to uneven temperatures among crates. This study proposes evaluating the suitability of Cassette-type Fan Coil Units (CT-FCUs) in cold storages to enhance airflow and cooling rates. Cold storage with CM-FCUs was modeled, simulated, and validated using experimental data. A similar cold storage with CT-FCUs was also modeled and simulated, and various thermal performance parameters were compared. In the proposed system, the maximum area-weighted average velocity was observed to be 20.5% higher than in the conventional cold storage. Similarly, the Performance Index (PI) demonstrated a 41.1% improvement, while temperature heterogeneity was 41.3% lower compared to the CM-FCU, indicating superior thermal performance in the cold storage with CT-FCUs. These findings suggest that the proposed CT-FCUs outperformed the CM-FCUs in terms of thermal performance.