Abstract: This report aims to optimize the typical flat plate solar collector for the domestic solar heating system, considering improving solar collector efficiency and the useful solar energy gain enhancement. Consequently, piping costs and pumping power will be reduced compared to the conventional flat plate solar collector to get a compact and lightweight structure. They considered the flow distribution, which is crucial to enhancing the solar collector efficiency. Numerical studies were performed at two serpentine tube solar collector diameters (8 mm and 6 mm); both are identical in wall thickness, number of tubes, number of bends, the distance between tubes, and tube length. Several tube lengths are applied to each diameter to optimise, design, and evaluate the performance of both the serpentine tube collector energy gain and the economic benefits. Thermodynamic and heat transfer improvements are considered in this study applied to both models. Where the Reynolds number and the Dean number are significantly higher for the 6 mm tube, about five times, in contrast to the 8 mm tube. The serpentine tube length to diameter ratio (L/d) for the 6 mm diameter tube is 33 % higher than that for the 8 mm diameter tube, which reveals the thermodynamic and heat transfer performance enhancement of the collector tubes. Tube diameter variations have no significant influence on fin efficiency (absorber plate), but it has a considerable influence on the breadth reduction, which ranges between 91 % to 98 %. The tube collector efficiency of the 6 mm tube ranges among 78% to 94% in contrast to the 8 mm tube, which drops to 74% to 89%. Moreover, the heat removal factor FR of the serpentine tube collectors' 6 mm and 8 mm is 98% and 91%, respectively. The fluid pressure drops in the serpentine tube collector correspond to tube diameter and length, while the pressure drop of the 8 mm tube ranges between 55 % to 80 % of the 6 mm tube for all tube lengths investigated. The annual collector heat gain of the 6 mm serpentine tube collector is 3982.5 W, which is approximately 25 % higher than that of the 8 mm serpentine tube collector. The financial analysis of the 6 mm serpentine tube collector shows a reduction of 22 % when compared to the 8 mm serpentine tube collector. The Propylenglycol 38% water mixture was applied in this study as the working fluid in the serpentine tube collector to determine the optimal operation performance of all samples stated earlier. In the particular studied case, the absorber plate width is considered to prove its influence on the collector performance. Moreover, fluid pressure drop, Reynold Number, and Dean Number in the collector tube. Keywords: flat plate solar collector, domestic solar heating system. Title: FLAT PLATE SOLAR COLLECTOR OPTIMIZATION USING DESIGN OF EXPERIMENTS APPROACH Author: ENG - MUATH ALNUAIMI, ENG - BADER ALFADLY International Journal of Mechanical and Industrial Technology ISSN 2348-7593 (Online) Vol. 14, Issue 1, April 2026 - September 2026 Page No: 10-28 Research Publish Journals Website: www.researchpublish.com Published Date: 21-April-2026 DOI: https://doi.org/10.5281/zenodo.19680666 Paper Download Link (Source) https://www.researchpublish.com/papers/flat-plate-solar-collector-optimization-using-design-of-experiments-approach
ALNUAIMI et al. (Tue,) studied this question.