Potential applications of inserts in solar thermal energy systems – A review to identify the gaps and frontier challenges

Rashidi, Saman; Kashefi, Mohammad Hossein; Hormozi, Faramarz

doi:10.1016/j.solener.2018.07.017

Cited by 79 publications

(14 citation statements)

References 106 publications

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“…In the literature, many studies are available about thermal enhancement using turbulators, and many of them are reported in Ref. [209][210][211][212].…”

Section: Thermal Performance and Modelingmentioning

confidence: 99%

Parabolic trough solar collectors: A general overview of technology, industrial applications, energy market, modeling, and standards

Tagle-Salazar

Nigam

Rivera-Solorio

2020

Green Processing and Synthesis

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Many innovative technologies have been developed around the world to meet its energy demands using renewable and nonrenewable resources. Solar energy is one of the most important emerging renewable energy resources in recent times. This study aims to present the state-of-the-art of parabolic trough solar collector technology with a focus on different thermal performance analysis methods and components used in the fabrication of collector together with different construction materials and their properties. Further, its industrial applications (such as heating, cooling, or concentrating photovoltaics), solar energy conversion processes, and technological advancements in these areas are discussed. Guidelines on commercial software tools used for performance analysis of parabolic trough collectors, and international standards related to performance analysis, quality of materials, and durability of parabolic trough collectors are compiled. Finally, a market overview is presented to show the importance and feasibility of this technology. We believe the compilation of reviews related to the above aspects will further provide impetus for the development of this technology in the near future.

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“…In the literature, many studies are available about thermal enhancement using turbulators, and many of them are reported in Ref. [209][210][211][212].…”

Section: Thermal Performance and Modelingmentioning

confidence: 99%

Parabolic trough solar collectors: A general overview of technology, industrial applications, energy market, modeling, and standards

Tagle-Salazar

Nigam

Rivera-Solorio

2020

Green Processing and Synthesis

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“…Recent investigations have been done to study the potential applications of different inserts including wire coils [9,10], vortex generators [11][12][13][14], and twisted tapes [15][16][17][18] for several solar thermal applications. However, few researchers have investigated the optimal configurations of inserts applied to SWH at the moderate temperature of the working fluid [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Parametric optimization of a stamped longitudinal vortex generator inside a circular tube of a solar water heater at low Reynolds numbers

et al. 2021

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Solar Water Heater (SWH) has low efficiency and the performance of this type of device needs to be improved to provide useful and ecological sources of energy. The passive techniques of augmentation heat transfer are an effective strategy to increase the convective heat transfer coefficient without external equipment. In this way, recent investigations have been done to study the potential applications of different inserts including wire coils, vortex generators, and twisted tapes for several solar thermal applications. However, few researchers have investigated inserts in SWH which is useful in many sectors where the working fluid operates at moderate temperatures. The longitudinal vortex generators (LVG) have been applied to promote heat transfer enhancement with a low/moderate pressure drop penalty. Therefore, the present work investigated optimal geometric parameters of LVG to enhance the heat transfer for a SWH at low Reynolds number and laminar flow, using a 3D periodical numerical simulation based on the Finite Volume Method coupled to the Genetic Algorithm optimization method (NSGA-II). The LVG was stamped over a flat plate inserted inside a smooth tube operating under a typical residential application corresponding to Reynolds numbers of 300, 600, and 900. The geometric parameters of LGV were submitted to the optimization procedure which can find traditional LVG such as rectangular-winglet and delta-winglet or a mix of them. The results showed that the application of LGVs to enhance heat transfer is an effective passive technique. The different optimal shapes of the LVG for all Reynolds numbers evaluated improved more than 50% of heat transfer. The highest augmentation heat transfer of 62% is found for the Reynolds number 900. However, the best thermo-hydraulic efficiency value is found for the Reynolds number of 600 in which the heat transfer intensification represents 55% of the pressure drop penalty.

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“…Thermal performance augmentation plays a vital duty in the manufacturing of thermohydraulic equipment as for example, solar energy systems [1,2], ventilation units, air conditions, and refrigeration industry. Increasing the thermal efficiency of the heat exchangers can reduce the energy costs and also the size of these systems.…”

Section: Introductionmentioning

confidence: 99%

Turbulent Flows Inside Pipes Equipped With Novel Perforated V-Shaped Rectangular Winglet Turbulators: Numerical Simulations

Nakhchi

Rahmati

2020

Journal of Energy Resources Technology

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In this study, computational simulations have been performed to investigate the turbulent characteristics and energy consumption through heat exchanger tubes equipped by new perforated V-shaped rectangular winglet (PVRW) turbulators. The effects of the holes intensity on the velocity and temperature contours are additionally investigated. The Reynolds number, hole diameter ratio, and the number of holes selected are in the range of 5000 ≤ Re ≤ 18,000, 0 ≤ DR ≤ 0.40, and 0 ≤ N ≤ 14, respectively. Renormalization group (RNG) k–ε turbulent model which is a finite volume solver is utilized for the computational fluid dynamics (CFD) simulation. It was noticed that the proposed perforated turbulators could considerably intensify the thermal performance compared to typical VRW inserts. It is found that the recirculating flow generated by the PVRW augments the fluid mixing and transfers the heat from the pipe walls to the core of the tube. The simulations illustrate that the amount of heat transfer enhances 25.2% reducing the DR from 0.4 to 0.13 at Re = 18,000 and N = 14. Also, using PVRW turbulators with N = 7 and DR = 0.26 augments the average Nusselt number around 354.3% compared to the circular pipe without inserts. The highest thermal efficiency parameter of η = 2.25 could be obtained at Re = 5000 for the heat exchangers fitted by vortex generators with N = 14 and DR = 0.26.

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Potential applications of inserts in solar thermal energy systems – A review to identify the gaps and frontier challenges

Cited by 79 publications

References 106 publications

Parabolic trough solar collectors: A general overview of technology, industrial applications, energy market, modeling, and standards

Parabolic trough solar collectors: A general overview of technology, industrial applications, energy market, modeling, and standards

Parametric optimization of a stamped longitudinal vortex generator inside a circular tube of a solar water heater at low Reynolds numbers

Turbulent Flows Inside Pipes Equipped With Novel Perforated V-Shaped Rectangular Winglet Turbulators: Numerical Simulations

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