Review of development of artificial roughness in solar air heater and performance evaluation of different orientations for double arc rib roughness

Lanjewar, Atul; Bhagoria, J.L.; Agrawal, Muskan

doi:10.1016/j.rser.2014.11.081

Cited by 44 publications

(14 citation statements)

References 28 publications

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“…Figure 17 shows evolution of the friction factor for square or rectangular depending on the Reynolds number. As expected and con rmed in the literature [15,19], the friction factor decreases when Reynolds number increases. Indeed, the friction factor is high at low Reynolds numbers because the laminar sublayer is thick enough to submerge the rib; moreover, the viscous forces are important enough to absorb disturbances caused by ribs.…”

Section: Heat Transfer Analysissupporting

confidence: 89%

“…More recently, new review analysis and research articles have been published [13][14][15] as proof of the great interest in and the importance of this heat transfer technique. Some authors investigated the e ect of three-side arti cially roughened solar air heaters on the enhancement of Nusselt number and found that it was superior by 21-78% over one-side roughened solar air heater for the range of parameters investigated.…”

Section: Introductionmentioning

confidence: 99%

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Comparative Study of the Effect of Two Type of Ribs on Thermal Performance of Solar Air Heaters

2017

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Abstract. This paper aims to analyze uid ow characteristics and heat transfer augmentation in the air duct of a solar air heater using CFD techniques. The air duct has a rectangular section, the top wall is the glazing and the bottom one is the absorber provided with transverse rectangular or squared ribs. The simulations are performed in the turbulent regime and RANS formulation is used to model the ow and resolve mass, momentum, and energy equations using Finite Volumes method. The air ow analysis shows that the velocity pro le is not disturbed by the ribs outside the laminar sublayer. Heat transfer analysis based on the calculation of Nusselt Number, friction factor, and thermo-hydraulic performance highlights the heat transfer enhancement and no big friction losses are recorded. A comparative study between two rib shapes (square and rectangular) is performed, which shows better thermohydraulic performance of the rectangular ribs.

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Section: Heat Transfer Analysissupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Comparative Study of the Effect of Two Type of Ribs on Thermal Performance of Solar Air Heaters

2017

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“…Several techniques were proposed and implemented to improve heat transfer rate between absorber and mobile air. Corrugated absorber, [1,[5][6][7] Recyclable Aluminum cans (RAC) absorber [8], absorber fitted with rows of fins [9] and various artificial roughness geometries [10][11][12][13]. Yeh and Lin [4] studied the effect of placing parallels obstacles on solar air collector efficiency.…”

Section: Introductionmentioning

confidence: 99%

Simulation study of solar air collector with offset strip fin absorber plate for drying agricultural products in a semi-arid climate

Benseddik¹,

Aberqi²,

Khanniche³

et al. 2018

IJHT

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In this current contribution, a parametric investigation of air flow rate at the inlets of solar air collector was carried out. Through a developed Matlab code effort was made to show the effect of the air flow rate on solar collector outlet temperature. From the simulation results a database of outlet temperature and corresponding flow rate variation with time was created. Then, isotherm contours were deduced and plotted. For drying temperature kept constant at a given value regardless the meteorological conditions fluctuation, the flow rate variation with time was fitted by smoothing spline function. The simulation study was done for three different meteorological scenarios: Clear sky day, partly cloudy day and cloudy day. It has been found also that drying with variable flow rate at optimum temperature equal to 50 ±1°C the amount of air that was aspired at the inlet was 1207.8 kg. By contrast, drying with constant flow rate a total 625.5kg of air was aspired and it might result in fluctuation in drying temperature which affects the dried product quality. Thus variable flow rate allows a gain ratio in the aspired air amount of 93% and better product quality. This is valid for clear sky day. In case of partly and cloudy day, flow rate gain ratio was 104% and 78% respectively.

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“…This act as an insulation and cause less heat to flow through absorber plate from solar irradiation. So this laminar sub-layer has to be break [2], [3], [4]. So concept of artificial came into existence and researchers are trying to find new methods of making new compact design of roughness.…”

Section: Concept Of Artificial Roughnessmentioning

confidence: 99%

Solar Air Heater with W-shaped roughness on Absorber plate.

Gaikwad¹,

Deshmukh²

2019

IJITEE

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The analysis is made for Reynolds number of 18000 – 21000. The thermal performance is investigated for W – shaped roughness of thickness (t) 5mm, length of 10.5 cm, with an angle of 25°. The simulation is carried out using solar irradiance as heat input at the location of Amravati 20.93°N 77.75°E. Comparison of Reynolds no and Nusselt no is made. The thermal efficiency is found to increase as the temperature goes on increasing simultaneously the pressure at outlet is greater than inlet pressure. The mechanical power which is required is increased due to the roughness present on absorber plate. The heat transfer between smooth and roughened surface is compared. The experimental results are compared with analytical results on ANSYS 18.1. The thermal efficiency for the smooth surface is around 40 – 45% at particular temperature after roughening the absorber plate the efficiency increased upto 50 – 60% for the same temperature.

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Review of development of artificial roughness in solar air heater and performance evaluation of different orientations for double arc rib roughness

Cited by 44 publications

References 28 publications

Comparative Study of the Effect of Two Type of Ribs on Thermal Performance of Solar Air Heaters

Comparative Study of the Effect of Two Type of Ribs on Thermal Performance of Solar Air Heaters

Simulation study of solar air collector with offset strip fin absorber plate for drying agricultural products in a semi-arid climate

Solar Air Heater with W-shaped roughness on Absorber plate.

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