Efficiency enhancement in solar air heaters by modification of absorber plate-a review

Aravindh, M. A.; Saritha, Appukuttan

doi:10.1080/15435075.2016.1183207

Cited by 23 publications

(14 citation statements)

References 52 publications

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“…Solar air collectors may be categorized, according to their absorber types, as non-porous, if the air stream does not flow through the absorber (only above and/or below the absorber surface, as shown in Figure 2a,b), or porous, if the air stream flows through the absorber (Figure 2c) [7,12,14,15]. In order to compensate for the poor heat transfer characteristics of the air, the absorber must be designed in such a way to maximize the heat transfer from the absorber to the air stream.…”

Section: Collector Unitmentioning

confidence: 99%

“…In order to compensate for the poor heat transfer characteristics of the air, the absorber must be designed in such a way to maximize the heat transfer from the absorber to the air stream. This is mainly achieved by increasing the turbulence of the air inside the collector and the heat transfer area of the absorber [2,11,15]. In non-porous absorbers, this is done by modifying the absorber plate with fins, obstacles, roughened surfaces, or corrugated surfaces.…”

Section: Collector Unitmentioning

confidence: 99%

“…In non-porous absorbers, this is done by modifying the absorber plate with fins, obstacles, roughened surfaces, or corrugated surfaces. Porous absorbers use porous materials, such as wire meshes or perforated plates, to enhance the heat transfer characteristics of the absorber [3,12,15].…”

Section: Collector Unitmentioning

confidence: 99%

“…However, this increase in heat transfer is also accompanied by an undesirable increase in the pumping power due to increased friction losses. Therefore, the design of the absorber surface should be implemented with the aim of maximizing heat transfer but minimizing friction losses [2,11,13,15,[18][19][20].…”

Section: Work Objectivesmentioning

confidence: 99%

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Thermo-Hydraulic Performance of Solar Air Collectors with Artificially Roughened Absorbers: A Comparative Review of Semi-Empirical Models

Araújo¹

2020

Energies

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Due to the poor thermal characteristics of the air, the absorber roughness of solar air collectors is commonly artificially increased in order to enhance the heat transfer to the air stream. However, this is also accompanied by an undesirable increase in the pumping power due to increased friction losses. As a result, several authors have experimentally investigated several ways of maximizing the heat transfer while minimizing the friction losses of different absorbers, resulting in the development of semi-empirical functions relating the Nusselt number (a measure of heat transfer) and the friction factor (a measure of friction losses) to the Reynolds number and the roughness parameters considered for each absorber. The present paper reviews, considering the publications from the last ten years, these semi-empirical functions. Moreover, the optimum roughness parameters and operating conditions of the absorbers were estimated by finding the maximum values of two performance parameters (the thermo-hydraulic efficiency and effectiveness), calculated using the semi-empirical functions, in order to classify the absorbers in terms of their energy characteristics. This approach proves to be a rather effective way of optimizing the roughness characteristics of solar air collector absorbers. It is also concluded that, considering the range of absorbers analyzed here, generally, multiple V-shaped ribs with gaps provide the most effective roughness geometry.

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Section: Collector Unitmentioning

confidence: 99%

Section: Collector Unitmentioning

confidence: 99%

Section: Collector Unitmentioning

confidence: 99%

Section: Work Objectivesmentioning

confidence: 99%

See 2 more Smart Citations

Thermo-Hydraulic Performance of Solar Air Collectors with Artificially Roughened Absorbers: A Comparative Review of Semi-Empirical Models

Araújo¹

2020

Energies

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“…Jiandong et al [15] studied the thermal efficiency of a flat plate solar collector by changing the collector tube spacing, length, diameter, thickness of absorber plate and insulation. Aravindh and Sreekumar [16] present a review of modifications of an absorber plate for effective efficiency in solar air heaters.…”

Section: Introductionmentioning

confidence: 99%

The Effect of the Use of Different Cover Materials on Heat Transfer in Flat Solar Collectors

Tekkalmaz

Timuralp

Sert

2020

Journal of Thermal Engineering

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In this study, combined thermal radiation and natural convection heat transfer from glass and plastic cover flat solar collectors is examined by varying tilt angle and cover materials. The flat-plate solar collector tilt angle is varied from 0º to 45º. The performance of glass, lexan, and acrylic cover materials is investigated. Numerical simulations have been performed for various solar collector thicknesses exposed to external ambient temperature and wind heat transfer coefficient. Continuity, momentum and the energy equations, along with the Boussinesq approach, are solved with the finite volume method using the SIMPLE algorithm. The cover temperature and the top loss coefficient are calculated for each cover material, collector tilt angle and bottom plate temperature, wind heat transfer coefficient and external ambient temperature. The flow and temperature field are obtained, and the mean convection and radiation Nusselt numbers are calculated for the bottom plate. The analytically and numerically computed glass cover temperatures are found to be in perfect agreement. The top loss coefficient of the plastic cover is lower than that of the glass cover. It is determined that with increasing heat input from the bottom plate, the top loss coefficient and the mean cover material temperature increase linearly. As the external ambient temperature increases, the top loss coefficient and the cover material temperature do not present any significant change.

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Role of Solar Drying Systems to Mitigate CO2 Emissions in Food Processing Industries

Rajarajeswari

Hemalatha

Saritha

2018

Green Energy and Technology

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Efficiency enhancement in solar air heaters by modification of absorber plate-a review

Cited by 23 publications

References 52 publications

Thermo-Hydraulic Performance of Solar Air Collectors with Artificially Roughened Absorbers: A Comparative Review of Semi-Empirical Models

Thermo-Hydraulic Performance of Solar Air Collectors with Artificially Roughened Absorbers: A Comparative Review of Semi-Empirical Models

The Effect of the Use of Different Cover Materials on Heat Transfer in Flat Solar Collectors

Role of Solar Drying Systems to Mitigate CO2 Emissions in Food Processing Industries

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