Potential improvements in the optical and thermal efficiencies of parabolic trough concentrators

Wirz, Men; Petit, Jules; Haselbacher, Andreas; Steinfeld, Aldo

doi:10.1016/j.solener.2014.05.002

Cited by 103 publications

(30 citation statements)

References 47 publications

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“…The increase in pressure drop is much more pronounced at high Reynolds numbers and is much larger than the increase in heat transfer performance. To incorporate this increase in pressure drop in the performance assessment, Wirtz et al [72] suggested an expression for thermal efficiency that considers both the increase in thermal performance as well as the effect of pumping power as: It can be seen from the figures that higher increase in thermal efficiency occur at high values of inlet temperatures. This is probably because, with the high concentration ratio used, high absorber tube temperatures will result and since the emissivity and thus receiver thermal loss increases with temperature, any reduction in absorber tube temperature due to heat transfer enhancement will lead to increased thermal performance.…”

Section: Thermal Efficiencymentioning

confidence: 99%

Thermal performance and entropy generation analysis of a high concentration ratio parabolic trough solar collector with Cu-Therminol®VP-1 nanofluid

Mwesigye

Huan

Meyer

2016

Energy Conversion and Management

199

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This paper presents results of a numerical study on the thermal and thermodynamic performance of a high concentration ratio parabolic trough solar collector using Cu- Above a certain Reynolds number, further increase in the Reynolds numbers makes the entropy generation higher than that of a receiver with only the base fluid. Key wordsConcentration ratio, entropy generation, nanofluid, parabolic trough receiver, thermal efficiency. †

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Section: Thermal Efficiencymentioning

confidence: 99%

Thermal performance and entropy generation analysis of a high concentration ratio parabolic trough solar collector with Cu-Therminol®VP-1 nanofluid

Mwesigye

Huan

Meyer

2016

Energy Conversion and Management

199

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“…However, the overall collector efficiency is the ratio of the useful thermal energy to the absorbed solar energy taking the effect of pumping power into consideration, as suggested by Wirz et al as follows:

η_{overall} = \frac{Q_{u -} W_{p} / η_{el}}{Q_{s}},

where η el is the electrical efficiency of the power block which was taken as 32.7%. However, W p is pumping power (W) and can be calculated by the following equations:

W_{p} = normalΔ P V^{.},

where V .…”

Section: Mathematical Formulations Of Ptcsmentioning

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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“…Wirz et al, 2014;Ghadirijafarbeigloo et al, 2014;Cheng et al, 2012 andHe et al, 2011). These researchers used SolTrace or another Monte Carlo code to capture the non-uniform solar heat flux on the absorber pipe of a parabolic trough collector and then with additional software map their results into the fluid flow domain for a computational thermal simulation.…”

Section: Lfc Radiation Modelling In Ansys Fluentmentioning

confidence: 99%

A novel computational approach to combine the optical and thermal modelling of Linear Fresnel Collectors using the finite volume method

2015

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A computational approach is presented, which uses the finite volume (FV) method in the Computational Fluid Dynamics (CFD) solver ANSYS Fluent to conduct the ray tracing required to quantify the optical performance of a line concentration Concentrated Solar Power (CSP) receiver, as well as the conjugate heat transfer modelling required to estimate the thermal efficiency of such a receiver. A Linear Fresnel Collector (LFC) implementation is used to illustrate the approach. It is shown that the Discrete Ordinates method can provide an accurate solution to the Radiative Transfer Equation (RTE) if the shortcomings of its solution are resolved appropriately in the FV CFD solver. The shortcomings are due to false scattering and the socalled ray effect inherent in the FV solution. The approach is first evaluated for a 2-D test case involving oblique collimated radiation and then for a more complex 2-D LFC optical domain based on the FRESDEMO project. For the latter, results are compared with and validated against those obtained with the Monte Carlo ray tracer, SolTrace. The outcome of the FV ray tracing in the LFC optical domain is mapped as a non-uniform heat flux distribution in the 3-D cavity receiver domain and this distribution is included in the FV conjugate heat transfer CFD model as a volumetric source. The result of this latter model is the determination of the heat transferred to the heat transfer fluid running in the collector tubes, thereby providing an estimation of the overall thermal efficiency. To evaluate the effectiveness of the phased approach in terms of accuracy and computational cost, the novel 2-D:3-D phased approach is compared with results of a fully integrated, but expensive 3-D optical and thermal model. It is shown that the less expensive model provides similar results and hence a large cost saving. The novel approach also provides the benefit of working in one simulation environment, i.e. ANSYS Workbench, where optimisation studies can be carried out to maximise the performance of linear CSP reflector layout and receiver configurations.

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Potential improvements in the optical and thermal efficiencies of parabolic trough concentrators

Cited by 103 publications

References 47 publications

Thermal performance and entropy generation analysis of a high concentration ratio parabolic trough solar collector with Cu-Therminol®VP-1 nanofluid

Thermal performance and entropy generation analysis of a high concentration ratio parabolic trough solar collector with Cu-Therminol®VP-1 nanofluid

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

A novel computational approach to combine the optical and thermal modelling of Linear Fresnel Collectors using the finite volume method

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