Investigation of exergy efficiency in shell and helically coiled tube heat exchangers

Alimoradi, Ashkan

doi:10.1016/j.csite.2016.12.005

Cited by 59 publications

(11 citation statements)

References 17 publications

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“…Different experimental and computational methods studies have conducted to analyze the effects of 1* Corresponding author. E-mail address: itimaddawood_eng@uodiyala.edu.iq DOI: 10.24237/djes.2021.14109 secondary flow motion induced by curvature and centrifugal force in helical coils, these studies clarified the flows within helically coiled by laminar and turbulent flows [2][3][4][5][6]. Eustice [7] has introduced experimental study to investigate the flow within the helical coil tube made of glass and full of water, and it has been noted that the centrifugal force induces secondary flow, and this is the essence of curved flow.…”

Section: Introductionmentioning

confidence: 98%

Evaluation Analysis of Double Coil Heat Exchanger for Heat Transfer Enhancement

Ali

Jumaah

Khadom

2021

DJES

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In order to maximize the thermal efficiency of shell and coil heat exchangers, substantial research has been done and geometrical modification is one way to improve the exchange of thermal energy between two or more fluids. One of the peculiar features of coiled geometry is that the temperature distribution is highly variable along the circumferential section due to the centrifugal force induced in the fluid. Moreover, most researchers are concentrated on using a shell and single helical coil heat exchanger to enhance the heat transfer rate and thermal efficiency at different operating parameters. Therefore, the aim of this study is to investigate temperature variation ((T-1, T-2, T-3 and T-4) across a shell and single/double coil heat exchanger at different coil pitches, hot water flow rate, and cold-water flow rate along the outer surface of the coil using experimental and numerical analysis. For single and double coil heat exchangers, Computational Fluid Dynamics (CFD) is carried out using pure water with a hot water flow rate ranging between 1-2 l/min for the coil side heat exchanger. For single coil heat exchangers, the numerical analysis findings showed a good agreement with experimental four-temperature measurement results (T-1, T-2, T-3 and T-4) with an error rate of 1.80%, 3.05%, 5.34% and 2.17% respectively. Moreover, in the current double coil analysis, the hot outlet temperature decreased by 3.07% compared to a single coil (baseline case) at a 2.5L/min hot water flow rate. In addition, increasing the coil pitch will increase the contact between the hot fluid and the coil at a constant hot water flow rate and thereby decrease the hot fluid outlet temperature. Finally, a computational analysis was carried out to examine the flow structure inside single and double coil heat exchangers, and the findings indicated that the effect of centrifugal forces in double coil heat exchangers at various coil pitches caused the secondary flow to be substantially reduced.

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Section: Introductionmentioning

confidence: 98%

Evaluation Analysis of Double Coil Heat Exchanger for Heat Transfer Enhancement

Ali

Jumaah

Khadom

2021

DJES

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“…The optimization results show that the maximum thermal efficiency of the cycle and exergy and NPV (Net Percent Value) are occurred in the counter-flow recuperator with offset strip fin. Alimoradi [12] investigated the effect of effective and geometrical parameters on the exergy efficiency of a shell helical-coil heat exchanger. Their results displayed that, the efficiency of the coil which has the minimum diameter and maximum number of turns is higher when compared to the coils which have the same length.…”

Section: Introductionmentioning

confidence: 99%

Design and thermal-hydraulic optimization of a shell and tube heat exchanger using bees algorithm

et al. 2022

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The present study modifies the structural design of a shell-and-tube heat exchanger (STHE) by considering two key parameters such as the maximization of the overall heat transfer coefficient and minimization of the total pressure drop. Five geometric design variables which include the tube inside diameter, tube outside diameter, pitch size, baffle spacing, and the tube length are investigated for optimization. The governing equations for design and optimization of the STHE are evaluated; and the optimum design parameters are obtained by Bees Algorithm (BA). The selection of the important design parameters to achieve the proper design is evaluated by fixing each of these parameters, while the other the design parameters are selected as variable to optimize the effectiveness. Compared with the original STHE, the overall heat transfer coefficient is increased by 22.78 % with the minimum increase in the total pressure drop by 1.8%.

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“…They investigated exergy losses in a low pressure evaporator and concluded that fin density has low effect on exergy efficiency in HRSG. Exergy analysis in shell and helically coiled tube heat exchangers was investigated by Alimoradi . He considered water as a heat transfer fluid in shell and tubes.…”

Section: Introductionmentioning

confidence: 99%

“…Exergy analysis in shell and helically coiled tube heat exchangers was investigated by Alimoradi. 32 He considered water as a heat transfer fluid in shell and tubes. Geometrical variables effects on the exergy destruction were studied and the results showed that, with 50% increase of coil radius, it causes a 10.7% reduction in the exergy efficiency.…”

Section: Introductionmentioning

confidence: 99%

Exergy analysis of a hybrid solar‐fossil fuel power plant

Vakilabadi

Bidi

Najafi

et al. 2019

Energy Science & Engineering

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In this study, exergy analysis, energy analysis, and mathematical modeling are performed in a 35 MW solar‐fossil fuel power plant. The losses of exergy and energy in different components and also changes of the efficiency of exergy and energy are analyzed at a specific day, 20th June. The assumed power plant in this study is Solar Electric Generating Station VI (SEGS VI), located in California's Mojave Desert. A parametric study, under different working conditions, including different working pressures, temperatures, collector output temperature, steam flow rate, and heat transfer fluid (HTF) flow rate is studied and the effect of variation of parameters on the performance of the plant is investigated. Authors found that, the maximum exergy loss happens in the collector and the maximum energy loss occurs in the condenser. Energy analysis shows that 47% of the total loss energy in the cycle happens in the condenser, as the main component that wastes energy. From exergy analysis, the collector and then boiler are the main components wasting exergy where 68.32% of total exergy loss occurs in these two components in hybrid mode (solar‐fossil fuel). Exergy and Energy efficiency variations throughout the day show that minimum exergy efficiency (32.7%) and maximum energy efficiency (23%) occurs at 12 am. Exergy efficiency variation versus turbine inlet pressure shows that the maximum exergy efficiency (26%) accure at 95 bar. The changes of the absorbed heat and solar irradiation of the 20th of June shows a good agreement with the measured data in validated reference.

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Investigation of exergy efficiency in shell and helically coiled tube heat exchangers

Cited by 59 publications

References 17 publications

Evaluation Analysis of Double Coil Heat Exchanger for Heat Transfer Enhancement

Evaluation Analysis of Double Coil Heat Exchanger for Heat Transfer Enhancement

Design and thermal-hydraulic optimization of a shell and tube heat exchanger using bees algorithm

Exergy analysis of a hybrid solar‐fossil fuel power plant

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