Experimental performance analysis of low concentration ratio solar parabolic trough collectors with nanofluids in winter conditions

Rehan, Mirza Abdullah; Ali, Muzaffar; Sheikh, Nadeem Ahmed; Khalil, Muhammad; Chaudhary, Ghulam Qadar; Rashid, Tanzeel ur; Shehryar, Muhammad

doi:10.1016/j.renene.2017.11.062

Cited by 127 publications

(39 citation statements)

References 53 publications

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“…Rehan et al [51] experimentally studied the effect of Al 2 O 3 and Fe 2 O 3 nanoparticle dispersed in water with different weight fraction ranging from 0.2-0.3% and flow rates (1-2 L/min) on the thermal efficiency of the PTC in winter. It was concluded that at 2 L/min flow rate and 0.3 wt %, Al 2 O 3 /water and Fe 2 O 3 /water nanofluid application enhances the thermal efficiency by 13% and 11%, respectively.…”

Section: Experimental Studiesmentioning

confidence: 99%

Application of Nanofluids in Thermal Performance Enhancement of Parabolic Trough Solar Collector: State-of-the-Art

et al. 2019

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The present review paper aims to document the latest developments on the applications of nanofluids as working fluid in parabolic trough collectors (PTCs). The influence of many factors such as nanoparticles and base fluid type as well as volume fraction and size of nanoparticles on the performance of PTCs has been investigated. The reviewed studies were mainly categorized into three different types of experimental, modeling (semi-analytical), and computational fluid dynamics (CFD). The main focus was to evaluate the effect of nanofluids on thermal efficiency, entropy generation, heat transfer coefficient enhancement, as well as pressure drop in PTCs. It was revealed that nanofluids not only enhance (in most of the cases) the thermal efficiency, convection heat transfer coefficient, and exergy efficiency of the system but also can decrease the entropy generation of the system. The only drawback in application of nanofluids in PTCs was found to be pressure drop increase that can be controlled by optimization in nanoparticles volume fraction and mass flow rate.

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Section: Experimental Studiesmentioning

confidence: 99%

Application of Nanofluids in Thermal Performance Enhancement of Parabolic Trough Solar Collector: State-of-the-Art

et al. 2019

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“…The usage of Al 2 O 3 and Fe 2 O 3 nanoparticles in water with different concentrations (0.20%, 0.25%, and 0.30%) was recently studied by Rehan et al The authors reported an increase in the thermal efficiency by 13% with Al 2 O 3 and 11% with Fe 2 O 3 mixed with water. Moreover, Subramani et al tested the usage of TiO 2 /water nanofluid in the PTC using different volume fractions (0.05%, 0.10%, and 0.20%).…”

Section: Thermal Performance Improvement By Adding Nanoparticlesmentioning

confidence: 99%

An extensive review of various technologies for enhancing the thermal and optical performances of parabolic trough collectors

Abed

Afgan

2020

Int J Energy Res

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A wide range of engineering industrial applications require both the thermal and optical efficiencies of the system to be maximized with a reasonable low penalty for the friction factor and subsequently low losses in pressure. Among the family of concentrated solar power systems, parabolic trough collectors (PTCs), which have recently received significant attention, face similar challenges. The current work presents an extensive review of the PTC systems comparing recent and past technologies, which are widely being used to improve and enhance the thermal and optical efficiencies. Furthermore, the techniques used for single and two-phase flow modeling in numerical simulations, design variables, and experimental processes have been discussed in detail. The article also presents different numerical methods and analytical approaches of implementing the nonuniform solar distribution with different design parameters. Four main technologies are comprehensively addressed to effectively enhance the thermal performance of the PTCs; changing working heat transfer fluids, replacing the working fluids by nanofluids (single and hybrid) that have higher thermal-physical properties than those of base working fluids, inserting different tabulators with various design configurations, and finally combining the advantages of nanofluids and swirl generators in the same application. The article also critically summarizes the studies investigating the enhancement of thermal performance: use of novel design of PTCs and passive heat transfer enhancement techniques. Finally, a wide range of numerical and experimental studies are proposed for the future work related to the aforementioned main technologies. K E Y W O R D Sheat transfer enhancements, nanofluids, parabolic trough solar collectors, solar thermal energy, tabulators, thermal and optical performances

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“…Finally, to extend the optical path length of the solar radiation, a coating with a high reflectance is applied on the top‐half surface of the outer tube. For the dual‐nanofluid DAPTSC, the geometrical concentration ratio can be estimated as W /( D 2 + 2 × 3 t g ) ≈ 55, where W is the width of parabolic mirror (see Figure ). We assumed the uniform velocity at the inlet such that the mass flow rate in each tube can be expressed simply as

{\dot{m}}_{1} = f_{1} \times \overset{m}{true}

and

{\dot{m}}_{2} = f_{2} \times \overset{m}{true}

, where

\overset{m}{true}

is the total mass flow rate (ie,

\overset{m}{true} = {\dot{m}}_{1} + {\dot{m}}_{2}

) and f is the fraction of cross‐sectional area of each tube.…”

Section: Theoretical Modelmentioning

confidence: 99%

Comparative analysis of direct‐absorption parabolic‐trough solar collectors considering concentric nanofluid segmentation

et al. 2020

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Summary Nanofluids have been actively used in direct‐absorption solar collectors. In a direct‐absorption parabolic‐trough solar collector (DAPTSC) for medium‐high temperature regime, the nanofluids used to be contained in a transparent glass receiver located at the focal line of a parabolic mirror so that the solar radiation is concentrated to the glass receiver and absorbed volumetrically inside the collector. In order to further increase the thermal efficiency of a DAPTSC, we propose to insert an extra glass tube inside the nanofluid so that the nanofluid is separated into two concentric segmentations (ie, an inner section and an outer section), and apply a nanofluid of lower concentration in the outer section while a nanofluid of a higher concentration in the inner section. The proposed idea is numerically tested on four pairs of DAPTSCs (the variants obtained depending on whether there is a vacuum envelope and whether there is a reflective semicylindrical coating on the receiver). The results show that at the same particle concentration parameter, the DAPTSCs with two concentric segmentations of nanofluids outperform those with one uniform nanofluid for all configurations considered in this work. For a transparent case without an envelope, this efficiency increase is as high as 12.5% point when the inlet temperature is 350 K. In addition, parametric studies are performed for this best configuration to evaluate the effect of absorption coefficient, mass flow rate, collector length, solar irradiance, and convection heat transfer coefficient on the collector performance.

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Experimental performance analysis of low concentration ratio solar parabolic trough collectors with nanofluids in winter conditions

Cited by 127 publications

References 53 publications

Application of Nanofluids in Thermal Performance Enhancement of Parabolic Trough Solar Collector: State-of-the-Art

Application of Nanofluids in Thermal Performance Enhancement of Parabolic Trough Solar Collector: State-of-the-Art

An extensive review of various technologies for enhancing the thermal and optical performances of parabolic trough collectors

Comparative analysis of direct‐absorption parabolic‐trough solar collectors considering concentric nanofluid segmentation

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