Investigation of heat transfer enhancement in a new type heat exchanger using solar parabolic trough systems

Şahi̇n, Hacı Mehmet; Baysal, Eşref; Dal, Ali Rıza; Şahi̇n, Necmettin

doi:10.1016/j.ijhydene.2015.03.009

Cited by 63 publications

(22 citation statements)

References 34 publications

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“…Divan and Soni [20] found that this technique leads to a 330% increase in the Nusselt number and about 23 times greater friction factor when compared to the reference case. Similar results were found by Sahin et al [21]. The use of metal foams have been investigated by Jamal-Abad et al [22] and it is found to be a 3% thermal efficiency enhancement with 20 times greater friction factor.…”

Section: Introductionsupporting

confidence: 81%

Enhancing the Performance of Evacuated and Non-Evacuated Parabolic Trough Collectors Using Twisted Tape Inserts, Perforated Plate Inserts and Internally Finned Absorber

Bellos

Tzivanidis

2018

Energies

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Abstract:The thermal enhancement of parabolic trough collectors is a critical issue and numerous ideas have been applied in the literature on this domain. The objective of this paper is to investigate some usual thermal enhancement techniques for improving the performance of evacuated and non-evacuated receivers of parabolic trough solar collectors. More specifically, the use of twisted tape inserts, perforated plate inserts, and internally finned absorbers are compared with the reference case of the smooth absorber. The analysis is conducted with a developed and validated thermal model in Engineering Equation Solver. The collector is investigated for a typical flow rate of 100 L/min and for inlet temperatures between 50 • C and 350 • C with Syltherm 800 as working fluid. According to the final results, the use of internally finned absorber leads to the highest thermal efficiency enhancement, which is up to 2.1% for the non-evacuated collector and up to 1.6% for the evacuated tube collector. The perforated plate inserts and the twisted tape inserts were found to lead to lower enhancements, which are up to 1.8% and 1.5%, respectively, for the non-evacuated collector, while they are up to 1.4% and 1.2%, respectively, for the evacuated collector. Moreover, the pressure drop increase with the use of the thermal enhancement methods is investigated and the use of internally finned absorber is found again to be the superior technique with the performance evaluation criterion to be ranged from 1.5 to 1.8 for this case.

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Section: Introductionsupporting

confidence: 81%

Enhancing the Performance of Evacuated and Non-Evacuated Parabolic Trough Collectors Using Twisted Tape Inserts, Perforated Plate Inserts and Internally Finned Absorber

Bellos

Tzivanidis

2018

Energies

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“…17 Furthermore, the use of various flow-inserts as conical nozzles, conical-rings, V-nozzles, and screw-tapes has also been examined in other literature. 18,19 Munoz and Abanades 20 proved that the use of internal fins in the PTC absorber increases its thermal performance up to 2% when it is operating with Syltherm 800. Wang et al 21 proved that the use of dimples in the PTC absorber leads to Nusselt enhancement up to 23% when the collector operates with air.…”

Section: Introductionmentioning

confidence: 99%

Thermal and exergetic evaluation of parabolic trough collectors with finned absorbers operating with air

Bellos

Tzivanidis

Daniil

2017

Proceedings of the Institution of Mechanical Engineers, Part A:

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The objective of this work is to evaluate energetically and exergetically the use of internal longitudinal fins in parabolic trough collectors operating with air. Nine different finned absorbers are compared with the smooth absorber for various inlet temperatures up to 500℃. More specifically, the use of 4, 8, and 16 fins with lengths 5 mm, 10 mm, and 15 mm are examined. The simulation tool is Solidworks Flow Simulation and the examined parabolic trough collector is the Eurotrough module. According to the final results, the global maximum exergetic efficiency is 43.65% and it is achieved for 4 fins with 15 mm length, while the inlet temperature of the air is equal to 350℃ and the thermal efficiency is 67.98%. Moreover, in the cases of 8 and 16 fins, the optimum lengths exergetically are 10 mm and 5 mm respectively, a fact that proves the reverse relationship between the number of fins and the fin length. Finally, it is also important to be stated that greater number of fins and higher fin length not only lead to higher thermal performance but also to higher pressure losses; two factors are taken into consideration in the exergetic performance, which is the main evaluation index of this study.

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“…Önceki çalışmalarda [2,3,5] detayları verilen deneysel çalışmada iç içe borulu paralel yönlü zıt akışlı bir ısı değiştiricisi kullanılmıştır. Hava sürekli rejim ve türbülanslı akış şartlarını sağlamak için sistemde türbülatör olarak çeşitli adımlara sahip yay kullanılmıştır.…”

Section: Test Sisteminin Yapısı (Structure Of Test System)unclassified

“…[1]. Ancak ısı transferi artışına karşı ilave pompa gücünün birçok sistemde ihmal edilebilir seviyede olduğu da görülmektedir [2]. Isı transferindeki artış yüzey alanının büyütülmesinden daha ziyade ısı taşınım katsayısının arttırılmasıyla ilgilidir.…”

Section: Gi̇ri̇ş (Introduction)unclassified

Numerical Analisis by RNG k-ε Turbulent Model of a Concentric Tube Heat Exchanger with Coiled Wire Turbulator

Şahi̇n

Dal²,

Özkaya³

2020

Gazi Üniversitesi Fen Bilimleri Dergisi Part C: Tasarım Ve Teknoloji

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In this study, a concentric tube heat exchanger with coiled wire turbulators were analysised numerically by a CFD code namely ANSYS FLUENT using RNG k-ε Turbulent Model in order to be reduced heat exchanger sizes and increased heat transfer enhancement. Figure A. The changing of numerical Nu number according to Re numberPurpose: In this study, it is aimed to compare numerical models with an experimental system previously study in literature by using passive method one of heat transfer enhancement of a concentric tube heat exchanger with coiled wire turbulators. Theory and Methods:The analyses were done in a range of Reynolds (Re) number from 3000 to 18000. The numerical simulations were done by using a CFD code namely ANSYS FLUENT, using finite volume method. In numerical analysis, three main turbulence models of RNG k-ε were employed in the simulations such as Model ➀ (RNG-Standard wall function), Model ➁ (RNG-Non-Equilibrium wall function) and Model ➂ (RNG-Enhanced wall treatment). Results:The numerical analyses carried out to compare with the experimental results in order to determine the best fitting model using each three main turbulence models of RNG k-ε model, Model ➀ has given the best fitting result. Conclusion:When turbulence models are compared with experimental results; Model ➀ has given more fitting result than Model ➁. Model ➂ is far from experimental results compared to other solutions. No k-ε model is not fitting with the data obtained from the experiment results in the Re Number range of 3000 ≤ Re ≤ 7000. When close to Re number value of 7000, the Nu number values obtained by Model ➂ have been far from experimental results.

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Investigation of heat transfer enhancement in a new type heat exchanger using solar parabolic trough systems

Cited by 63 publications

References 34 publications

Enhancing the Performance of Evacuated and Non-Evacuated Parabolic Trough Collectors Using Twisted Tape Inserts, Perforated Plate Inserts and Internally Finned Absorber

Enhancing the Performance of Evacuated and Non-Evacuated Parabolic Trough Collectors Using Twisted Tape Inserts, Perforated Plate Inserts and Internally Finned Absorber

Thermal and exergetic evaluation of parabolic trough collectors with finned absorbers operating with air

Numerical Analisis by RNG k-ε Turbulent Model of a Concentric Tube Heat Exchanger with Coiled Wire Turbulator

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