scholarly journals A Review of Energy and Exergy Analyses of a Roughened Solar Air Heater

2020 ◽  
Vol 77 (2) ◽  
pp. 160-175
Author(s):  
Nguyen Minh Phu ◽  
Nguyen Thanh Luan
Keyword(s):  
Evaluation Criteria ◽  
Jet Impingement ◽  
Performance Parameter ◽  
Solar Air Heater ◽  
Absorber Plate ◽  
Air Heater ◽  
Metal Waste ◽  
Roughness Elements ◽  
Energy And Exergy ◽  
Arc Shape

In this paper, eleven roughness elements in solar air heater duct analysed both energy and exergy were reviewed. Various roughness geometries such as ribs, twisted tap, baffles, and metal waste were surveyed about heat transfer and friction when the air flow is passing absorber plate. Evaluation criteria of roughness on the absorber plate including thermohydraulic performance parameter, thermal efficiency, effective efficiency, and exergy efficiency were presented and compared. Results showed that protruded ribs in arc shape indicated the largest Nusselt number. The ribs exhibited the highest thermohydraulic performance parameter at a Reynolds number greater than 5000. Jet impingement with arc-shaped ribs and roughness elements of metal waste were found the smallest exergy efficiencies. The biggest effective and exergy efficiencies were obtained to be 70% and 1.9%, respectively. The thermohydraulic performance parameter varied from 0.5 to 2.0. The review paper aims to provide information about roughness geometries investigated both first and second laws of thermodynamics and figure of merits to overview artificial roughness in a solar air heater.

scholarly journals Modeling and Simulation of Turbulent Flows through a Solar Air Heater Having Square-Sectioned Transverse Rib Roughness on the Absorber Plate

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Anil Singh Yadav ◽  
J. L. Bhagoria
Keyword(s):  
Heat Transfer ◽  
Turbulent Flows ◽  
Convective Heat Transfer Coefficient ◽  
Performance Parameter ◽  
Roughness Height ◽  
Solar Air Heater ◽  
Absorber Plate ◽  
Air Heater ◽  
Relative Roughness ◽  
Flow Through

Solar air heater is a type of heat exchanger which transforms solar radiation into heat energy. The thermal performance of conventional solar air heater has been found to be poor because of the low convective heat transfer coefficient from the absorber plate to the air. Use of artificial roughness on a surface is an effective technique to enhance the rate of heat transfer. A CFD-based investigation of turbulent flow through a solar air heater roughened with square-sectioned transverse rib roughness has been performed. Three different values of rib-pitch (P) and rib-height (e) have been taken such that the relative roughness pitch (P/e=14.29) remains constant. The relative roughness height,e/D, varies from 0.021 to 0.06, and the Reynolds number, Re, varies from 3800 to 18,000. The results predicted by CFD show that the average heat transfer, average flow friction, and thermohydraulic performance parameter are strongly dependent on the relative roughness height. A maximum value of thermohydraulic performance parameter has been found to be 1.8 for the range of parameters investigated. Comparisons with previously published work have been performed and found to be in excellent agreement.

scholarly journals Performance analysis of solar air heater with jet impingement on corrugated absorber plate

2017 ◽  
Vol 10 ◽  
pp. 111-120 ◽  
Author(s):  
Alsanossi M. Aboghrara ◽  
B.T.H.T. Baharudin ◽  
M.A. Alghoul ◽  
Nor Mariah Adam ◽  
A.A. Hairuddin ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Jet Impingement ◽  
Solar Air Heater ◽  
Absorber Plate ◽  
Air Heater
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