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Proceedings ArticleDOI

Experimental and numerical analysis using CFD technique of the performance of the absorber tube of a solar parabolic trough collector with and without insertion

10 Apr 2013-pp 550-556
TL;DR: In this paper, numerical analyses have been conducted for the flow of fluid in the absorber tube of a cylindrical parabolic trough collector through CFD technique, where the authors have shown that the efficiency of the tube can be improved by increasing the overall surface area, which increases the heat transfer to the working fluid.
Abstract: In this work, numerical analyses have been conducted for the flow of fluid in the absorber tube of a cylindrical parabolic trough collector through CFD technique. The efficiency of the absorber tube can be improved by increasing the overall surface area, which increases the heat transfer to the working fluid. Analyses of the same have been done to see to what degree the insertions cause an improvement in heat transfer and as a result in increasing the outlet temperature of the working fluid. This has been carried out numerically by commercial CFD code Ansys CFX 12.0. The analysis has been carried out to study the effect of heat transfer in absorber tubes with and without insertions. The study also takes care in distributing different heat flux along the walls of the absorber tubes. The numerical analysis of the absorber tube without any insertions (plain tube) is validated with the experiments carried out on the absorber tube of a solar parabolic trough collector. After validating the numerical analysis, it is extended to study the effect of insertion in the performance of the absorber tube. The working fluid in all these studies is taken as water with different mass flow rates of 33 kg/hr, 63 kg/hr and 85 kg/hr. The temperature at the exit, pressure drop across the absorber tube, wall temperature and velocity along the mid-plane are plotted.
Citations
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Journal ArticleDOI
TL;DR: In this paper, a review of current and past studies to assess the optical and thermal performances of parabolic trough solar collectors, modeling approaches and the potential improvements proposed on behalf of the parabolic-trough solar collector design is presented.

206 citations

Journal ArticleDOI
TL;DR: In this article, a 2D:3D numerical optical, thermal and electric coupling approach for a hybrid compound parabolic concentrator photovoltaic/thermal (CPC-PV/T) collector using a nanofluid as a spectral beam filter is introduced.

54 citations

01 Jan 2014
TL;DR: In this paper, numerical analysis using CFD is performed by using inserts of different cross-section inside the fluid flow path of an absorber tube to study the flow characteristics, and the results of numerical analysis is validated with the experiments carried out with the parabolic trough collector.
Abstract: Absorber tube performance enhancement by using passive techniques is one of the major topics of research in the field of solar thermal power engineering. Earlier studies on ducts revealed that passive augmentation techniques have shown considerable enhancement in heat transfer. Experiments were conducted earlier on Parabolic Trough Collector (PTC) with plain absorber tube without inserts for different flow rate conditions. It was observed that fluid flow rate with 85 kg/hr has shown higher temperature difference for solar flux condition of 850 W/m 2 . In the present study, numerical analysis using CFD is performed by using inserts of different cross-section inside the fluid flow path of an absorber tube to study the flow characteristics. The fluid flow and heat transfer phenomena through a 3-dimensional absorber tube with varying heat source are obtained by solving the fundamental governing equations namely: conservation of mass, momentum and energy. Turbulence is modeled using SST k-ω model of closure. The heat transfer and pressure drop is calculated from the studies conducted for a mass flow rate of 85 kg/hr using the ANSYS CFX 12.1 software. The result of the numerical analysis is validated with the experiments carried out with the parabolic trough collector. The numerical study is carried out with triangle, inverted triangle and semi-circular inserts and compared with that of plain absorber tube. It has been found that triangle insertion gives optimized results with respect to uniform heat transfer which reduces the thermal fatigue even the pressure drop is relatively high compared to the plain absorber tube without insertion.

9 citations


Cites methods or result from "Experimental and numerical analysis..."

  • ...The values of the boundary conditions like operating temperature, mass flow rate of water are taken from the earlier experimental work [13]....

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  • ...Initially the absorber tube without insertion is numerically solved and validated against the same boundary conditions as that of the experimental setup and a very good correlation is obtained between the numerically predicted results and the experimental setup as reported in our previous work [13]....

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Journal ArticleDOI
TL;DR: In this article , the performance evaluation criterion (PEC) and efficiency of parabolic solar collector containing water/Al2O3−MWCNT hybrid nanofluid are numerically examined in the presence of finned and perforated twisted tape turbulators by employing two-phase flow approach.
Abstract: Renewable energy is a type of convenient energy obtained from renewable sources, which can be replaced naturally again on the human time scale. One of the most broadly employed types of renewable energy is solar energy. In the present study, the entropy generation, performance evaluation criterion (PEC), and efficiency of parabolic solar collector containing water/Al2O3−MWCNT hybrid nanofluid are numerically examined in the presence of finned and perforated twisted tape turbulators by employing two-phase flow approach. The volume fraction of nanoparticles (φ) changes from 0 to 3% and the Reynolds number (Re) range is 5000–35,000. The two-phase Eulerian-Eulerian model (EEM), k-ω turbulence model, finite volume method (FVM) method, and SIMPLEC algorithm are used for numerical simulations. The results demonstrate that the maximum change in the total entropy generation is 40.07% by changing the type of turbulator from a perforated tape to the finned vane turbulator which occurs at Re = 30,000 and φ= 3%. The maximum change in the collector efficiency is 1.62% by changing the type of turbulator from finned turbulator to perforated tape one which occurs at Re = 20,000 and φ = 0%. The maximum change in ANU is 13.65%, which occurs at Re = 15,000 and φ = 1%.It is more desirable to use the perforated twisted tape from the point of view of heat transfer, total entropy generation, PEC, and collector efficiency.

4 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of the sudden fluctuations in the solar radiation on the performance of the collector is reduced by means of evacuated tube collector filled with thermic fluids, such as dowtherm, therminol66, glycol water and ethylene glycol.
Abstract: The evacuated tube collector with U shape copper absorber tube is considered for the analysis. The experimental investigation is conducted on parabolic trough collector with U shape tube as absorber tube. The effect of the sudden fluctuations in the solar radiation on the performance of the collector is reduced by means of evacuated tube collector filled with thermic fluids. The analysis is performed with different thermic fluids such as dowtherm, therminol66, glycol water and ethylene glycol, are filled in the annular space between inner glass tube and U shape copper absorber tube. The experimentation is carried out at various mass flow rates from 20 to 100 LPH with the step-up flow rate of 20 LPH. A comparative study is carried out on various parameters such as effect of mass flow rate over instantaneous efficiency, useful heat gain and work input, etc. The characteristic curve of cylindrical parabolic trough collector (PTC) is also discussed. Experimental results show that, ethylene glycol gives better efficiency over mass flow rate and therminol66 gives best power heat ratio. Heat transfer mediums and its properties [specific heat capacity, thermal conductivity and dynamic viscosity] for all specified heat transfer fluids are also discussed. The results obtained with various specified heat transfer fluids filled in the annulus space of evacuated tube are compared with plain evacuated tube. It is observed that there is significant enhancement of overall instantaneous collection efficiency of the parabolic trough collector.

4 citations

References
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ReportDOI
01 Oct 2003
TL;DR: In this article, the authors describe the development, validation, and use of a heat transfer model implemented in Engineering Equation Solver, which determines the performance of a parabolic trough solar collector's linear receiver, also called a heat collector element.
Abstract: This report describes the development, validation, and use of a heat transfer model implemented in Engineering Equation Solver. The model determines the performance of a parabolic trough solar collector's linear receiver, also called a heat collector element. All heat transfer and thermodynamic equations, optical properties, and parameters used in the model are discussed. The modeling assumptions and limitations are also discussed, along with recommendations for model improvement.

667 citations


"Experimental and numerical analysis..." refers background in this paper

  • ...R. Forristall(2003)[8] conducted the heat transfer analysis and modelling of a parabolic solar trough collector using fluent and provided a very good guideline for the same....

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Journal ArticleDOI
Ze-Dong Cheng1, Ya-Ling He1, Juan Xiao1, Y.B. Tao1, R.J. Xu1 
TL;DR: In this article, the solar energy flux distribution on the outer wall of the inner absorber tube of a parabolic solar collector receiver is calculated successfully by adopting the Monte Carlo Ray-Trace Method (MCRT Method).

249 citations


"Experimental and numerical analysis..." refers background or methods in this paper

  • ...[2, 4, 8, 12] Weidong Huang et all (2011) [3] provided a new analytical method to determine the optical performance of the parabolic trough collector....

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  • ...Thundil Karuppa Raj([1]), Tangellapalli Srinivas([2]), M....

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  • ...Cheng et all (2010) [2] showed the use of Monte Carlo trace method for estimation of solar energy flux distribution on the outer wall of the absorber tube....

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Journal ArticleDOI
TL;DR: In this article, the effect of the utilization of internal finned tubes for the design of parabolic trough collectors with computational fluid dynamics tools is analyzed with reported experimental data regarding phenomena involved in finned tube applications and solar irradiation.

192 citations


"Experimental and numerical analysis..." refers background or methods in this paper

  • ...Munoz and Abanades (2011) [1] provided a CFD model for analysis of internally finned tubes with emphasis on pressure drop and temperature rise as defining parameters....

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  • ...Munoz and Abanades(2011)[4] mentioned the heterogeneous nature of flux distribution on the absorber wall and indicated how the use of internally finned tubes would resulted in homogenized temperature distribution on the absorber wall....

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Journal ArticleDOI
TL;DR: In this article, the thermal and fluid-dynamic behavior of a single-pass and double-pass solar parabolic trough collector is analyzed in the presence of recycle at the ends.

184 citations

Journal ArticleDOI
TL;DR: In this article, the authors used a variety of fluids (e.g., air, water, oil, R-113, ethylene glycol/water) for turbulent heat transfer in internally finned tubes.

112 citations