A study of heat transfer enhancement in a new solar air heater having circular type turbulators

Acır, Adem; Ata, İsmail

doi:10.1016/j.joei.2015.05.008

Cited by 39 publications

(6 citation statements)

References 20 publications

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“…Solar radiation is transformed into useful fluid heat (Qu) through the SAC absorber plate. Qu is calculated with the help of the following equations [15,16].…”

Section: Theoretical Calculationsmentioning

confidence: 99%

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Modeling of a solar air collector heat transfer coefficient with regression algorithms

Akpınar¹,

Daş²

2022

FUJECE

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Solar air collectors (SAC) are thermodynamic systems that convert solar energy into useful fluid energy. SACs are very common in heating, cooling, food drying, and many other low-temperature applications. In this study, the heat transfer coefficient in the SAC was calculated according to Newton's cooling law. The obtained values and the thermal performance of the SAC were examined during the sunshine period. At the same time, SAC heat transfer coefficient models were made with the help of regression algorithms (multiple linear regression, simple linear regression) using SAC temperature data obtained by experimental measurements (inlet fluid, outlet fluid, and absorber plate) and solar radiation data on the SAC. As a result of the modeling, linear mathematical equations expressing the heat transfer coefficient for SACs were obtained. Obtained experimental and model data were compared. SAC heat transfer coefficient values were modeled with a mean absolute error of 0.6.

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“…Solar radiation is transformed into useful fluid heat (Qu) through the SAC absorber plate. Qu is calculated with the help of the following equations [15,16].…”

Section: Theoretical Calculationsmentioning

confidence: 99%

“…and Comp. Eng., 1(1), [14][15][16][17][18][19][20][21][22][23]2022 E.K. Akpınar, M. Daş theoretical framework helps to understand a particular phenomenon better.…”

Section: Introductionmentioning

confidence: 99%

Modeling of a solar air collector heat transfer coefficient with regression algorithms

Akpınar¹,

Daş²

2022

FUJECE

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“…Zhang and Wang (2016) generated a vortex by inserting rectangular wings into a rectangle duct and later revealed that heat transfer can significantly increase with a rise in the rectangular winglet pair on the bottom wall of a channel. Acır and Ata (2016) enhanced the heat transfer in a solar air heater with circular turbulators and indicated that heat transfer rate, thermal performance factor and pressure loss tend to increase with a decrease in angle and Pitch ratio (P/D). Rivier et al (2015) studied the effects of the insertion of 45° or 60° elliptical turbulators into HX tubes with different diameter ratios on heat transfer enhancement and pressure drop.…”

Section: Introductionmentioning

confidence: 99%

Flow and Thermal Mechanisms in Receiver Tube of Parabolic Trough Collectors with Rings Axially Connected Together and Radially Connected to the Inner Tube Surface

Abdulhamed¹,

Adam²,

Ab-Kadir³

et al. 2019

J. Eng. Appl. Sci.

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Artificial obstructions on the underside of receiver tubes can increase the heat transfer coefficient between the receiver tubes (Heat Exchanger, HX) of Parabolic Trough Collectors (PTCs) and water as a working fluid. In this study, we numerically and experimentally tested the behavior of laminar mixed convective heat transfer in HX tube installed with baffles. These baffles are rings that are connected together axially and connected radially to the inner tube surface. Using ANSYS fluent Version 15.0, we performed computation fluid dynamics modeling to achieve heat transfer enhancement in HX tubes equipped with turbulator baffles under laminar flow conditions. Moreover, the effects of Pitch ratio (P/D) = 3, 6 and 10 and Reynolds number Re#480 were recorded. The novel application of the rings that are connected axially together and radially to the inner tube surface contributes to the long-term storage of thermal energy and promotes heat transfer via. conduction from the tube surface to the center line of the water flow within a short period. In the study, the baffles generated a vortex to increase the Nusselt number (Nu) inside the HX. To simulate heat flux, we calculated the constant wall heat flux of the receiver tube using an electric heater. Results indicated that using 20 rings as baffles instead of plain tubes improves heat transfer by up to 75%. As P/D decreased and re increased, the heat transfer rate, friction factor (f) and Thermal Enhancement Factor (TEF) increased.

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“…Acır and Ata [6] studied heat transfer, friction factor and thermal performance factor characteristics for a new solar air heater. They performed experimental tests using various turbulators.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Investigation of a Solar Air Heater Roughened by Ribs and Grooves

Yıldırım¹

2017

Journal of Thermal Engineering

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In this study, thermal and thermohydraulic efficiencies of a solar air collector having a roughened absorber with rib-grooved artificial roughness elements have been investigated and compared with the flat plate solar air collectors. The system has been theoretically investigated for different geometrical roughness parameters by help of energy balance equations between the elements of collector. Geometrical roughness parameters such as ratio of the relative roughness height (RRH), relative roughness pitch (RRP), and groove positions to pitch (GP/PR) are examined for Reynolds number range from 3000 to 21,000.

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A study of heat transfer enhancement in a new solar air heater having circular type turbulators

Cited by 39 publications

References 20 publications

Modeling of a solar air collector heat transfer coefficient with regression algorithms

Modeling of a solar air collector heat transfer coefficient with regression algorithms

Flow and Thermal Mechanisms in Receiver Tube of Parabolic Trough Collectors with Rings Axially Connected Together and Radially Connected to the Inner Tube Surface

Theoretical Investigation of a Solar Air Heater Roughened by Ribs and Grooves

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