THERMAL SCIENCE

International Scientific Journal

Suresshkumar Petchimuthu

,

Sathiya Moorthy Rajendran

PERFORMANCE ENHANCEMENT OF SOLAR AIR HEATERS THROUGH RIBBED ABSORBERS WITH VARIED HOLE CONFIGURATIONS

ABSTRACT
The performance of solar heaters for heating air could be significantly upgraded by adding obstructions on the absorber. Experiments were conducted to obtain both thermal performance and friction factor information inside an air heater channel containing convergent, divergent and uniform holes on ribs fixed on the absorber surface. This study covers a Reynolds number range of 3000-18000, rib heights, e, varying between 2 mm and 4 mm, hole diameters, D, spanning from 1- 3 mm, and ribs featuring various hole arrangements. Surface roughness effects on the Nusselt number and friction factor, f, were investigated, and the findings have been compared with that of a flat absorber. Nusselt number and friction factor increased through 3.54 and 2.7 times, respectively, over the flat absorber. At Re = 18000, the convergent hole rib (e = 4 mm, D = 2 mm) provided the greatest enhancements in Nusselt number and friction factor.
KEYWORDS
Hole Diameter, Rib Height, various hole arrangements, heat transfer, friction factor
PAPER SUBMITTED: 2025-11-13
PAPER REVISED: 2026-01-04
PAPER ACCEPTED: 2026-01-09
PUBLISHED ONLINE: 2026-03-07
DOI REFERENCE: https://doi.org/10.2298/TSCI251113022P
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2026, VOLUME 30, ISSUE No. 4, PAGES [2617 - 2628]
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Performance enhancement of solar air heaters through ribbed absorbers with varied hole configurations

© 2026 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International licence