Heat transfer, exergy, and cost: A sustainable analysis of concentric tube heat exchangers

This study investigates the heat transfer, exergetic performance, and overall cost of counter-flow concentric tube heat exchangers under various geometric and flow conditions. A systematic parametric analysis is performed using 2700 two-dimensional axisymmetric computational fluid dynamics simulatio...

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Main Authors: Samer Ali, Chadi Nohra, Georges El Achkar, Jalal Faraj, Mahmoud Khaled
Format: Article
Language:English
Published: Elsevier 2025-04-01
Series:Case Studies in Thermal Engineering
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Online Access:http://www.sciencedirect.com/science/article/pii/S2214157X25000930
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author Samer Ali
Chadi Nohra
Georges El Achkar
Jalal Faraj
Mahmoud Khaled
author_facet Samer Ali
Chadi Nohra
Georges El Achkar
Jalal Faraj
Mahmoud Khaled
author_sort Samer Ali
collection DOAJ
description This study investigates the heat transfer, exergetic performance, and overall cost of counter-flow concentric tube heat exchangers under various geometric and flow conditions. A systematic parametric analysis is performed using 2700 two-dimensional axisymmetric computational fluid dynamics simulations. The analysis spans Reynolds numbers from 1000 to 20000, covering both laminar and turbulent regimes, and considers four fluid combinations (air–air, air–water, water–air, water–water) with temperature-dependent properties. Geometric variations include three inner diameters (0.01 m, 0.02 m, 0.05 m), three diameter ratios (1.25, 1.5, 3), and three lengths (0.4 m, 0.6 m, 4 m). Results show that increasing Reynolds number enhances the heat transfer rate and overall heat transfer coefficient. For instance, the heat transfer coefficient remains below 60 W/m2⋅K for air–air configurations, rises to 100–150 W/m2⋅K for air–water and water–air cases, and reaches up to 2000 W/m2⋅K for water–water setups. Smaller inner diameters, lower diameter ratios, and longer heat exchangers achieve high effectiveness and exergetic efficiencies up to 0.8, indicating superior thermodynamic performance. However, these configurations often incur higher operating costs, exceeding 10,000–12,000 USD over a 10-year period for long, small-diameter units, compared to 2,000–2,600 USD for shorter or larger-diameter designs. This research provides a comprehensive framework to balance heat transfer enhancement, exergy utilization, and cost-effectiveness in designing sustainable heat exchanger systems.
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spelling doaj-art-b13b91d3b12a4af391b6c8f3255bef382025-08-20T01:57:36ZengElsevierCase Studies in Thermal Engineering2214-157X2025-04-016810583310.1016/j.csite.2025.105833Heat transfer, exergy, and cost: A sustainable analysis of concentric tube heat exchangersSamer Ali0Chadi Nohra1Georges El Achkar2Jalal Faraj3Mahmoud Khaled4Univ. Lille, Institut Mines-Télécom, Univ. Artois, Junia, ULR 4515 – LGCgE, Laboratoire de Génie Civil et géo-Environnement, F-59000 Lille, France; Corresponding author.Beirut Arab University, BAU, LebanonInternational Center in Fundamental and Engineering Thermophysics, Tianjin University of Commerce, Tianjin, China; Energy and Thermo-Fluid Group, Lebanese International University LIU, Bekaa, LebanonEnergy and Thermo-Fluid Group, Lebanese International University LIU, Bekaa, Lebanon; Energy and Thermo-Fluid Group, The International University of Beirut BIU, Beirut, LebanonEnergy and Thermo-Fluid Group, Lebanese International University LIU, Bekaa, Lebanon; GUST Center for Sustainable Development, Gulf University for Science and Technology, Kuwait; Correspondence to: Lebanese International University (LIU), Beirut Campus, Mouseitbeh, PO Box 146404 Mazraa, Lebanon.This study investigates the heat transfer, exergetic performance, and overall cost of counter-flow concentric tube heat exchangers under various geometric and flow conditions. A systematic parametric analysis is performed using 2700 two-dimensional axisymmetric computational fluid dynamics simulations. The analysis spans Reynolds numbers from 1000 to 20000, covering both laminar and turbulent regimes, and considers four fluid combinations (air–air, air–water, water–air, water–water) with temperature-dependent properties. Geometric variations include three inner diameters (0.01 m, 0.02 m, 0.05 m), three diameter ratios (1.25, 1.5, 3), and three lengths (0.4 m, 0.6 m, 4 m). Results show that increasing Reynolds number enhances the heat transfer rate and overall heat transfer coefficient. For instance, the heat transfer coefficient remains below 60 W/m2⋅K for air–air configurations, rises to 100–150 W/m2⋅K for air–water and water–air cases, and reaches up to 2000 W/m2⋅K for water–water setups. Smaller inner diameters, lower diameter ratios, and longer heat exchangers achieve high effectiveness and exergetic efficiencies up to 0.8, indicating superior thermodynamic performance. However, these configurations often incur higher operating costs, exceeding 10,000–12,000 USD over a 10-year period for long, small-diameter units, compared to 2,000–2,600 USD for shorter or larger-diameter designs. This research provides a comprehensive framework to balance heat transfer enhancement, exergy utilization, and cost-effectiveness in designing sustainable heat exchanger systems.http://www.sciencedirect.com/science/article/pii/S2214157X25000930Parametric studyHeat exchangersConcentric tubeOverall heat transfer coefficientLaminar flowTurbulent flow
spellingShingle Samer Ali
Chadi Nohra
Georges El Achkar
Jalal Faraj
Mahmoud Khaled
Heat transfer, exergy, and cost: A sustainable analysis of concentric tube heat exchangers
Case Studies in Thermal Engineering
Parametric study
Heat exchangers
Concentric tube
Overall heat transfer coefficient
Laminar flow
Turbulent flow
title Heat transfer, exergy, and cost: A sustainable analysis of concentric tube heat exchangers
title_full Heat transfer, exergy, and cost: A sustainable analysis of concentric tube heat exchangers
title_fullStr Heat transfer, exergy, and cost: A sustainable analysis of concentric tube heat exchangers
title_full_unstemmed Heat transfer, exergy, and cost: A sustainable analysis of concentric tube heat exchangers
title_short Heat transfer, exergy, and cost: A sustainable analysis of concentric tube heat exchangers
title_sort heat transfer exergy and cost a sustainable analysis of concentric tube heat exchangers
topic Parametric study
Heat exchangers
Concentric tube
Overall heat transfer coefficient
Laminar flow
Turbulent flow
url http://www.sciencedirect.com/science/article/pii/S2214157X25000930
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AT georgeselachkar heattransferexergyandcostasustainableanalysisofconcentrictubeheatexchangers
AT jalalfaraj heattransferexergyandcostasustainableanalysisofconcentrictubeheatexchangers
AT mahmoudkhaled heattransferexergyandcostasustainableanalysisofconcentrictubeheatexchangers