LAUSR

Abstract In this experimental study, a flat plate solar collector was constructed and examined for absorbing and transferring heat from soil to fluid. The light source was an infrared lamp with average illumination intensity of 3150 lux. For the first time, α-Al2O3, γ-Al2O3, and Bentonite powder were used for heat absorption, storage, and its transfer to the operating fluid. The average particles size of α-Al2O3, γ-Al2O3, and Bentonite were 150 μm, 45 μm, and 75 μm, respectively. The operating fluid was distilled water. The absorption efficiency of α-Al2O3, γ-Al2O3 and Bentonite was 5.50%, 30.90%, and 9.99%, respectively, in the absence of operating fluid. However, the absorption efficiency of α-Al2O3, γ-Al2O3 and bentonite powders increases to 55.23%, 89.45%, and 70.50%, respectively in presence of circulating fluid circulates. The physical properties of all samples were evaluated to check the repeatability of the experiments using various analyses i.e., FT-IR, XRD, SEM, XRF, DSC and BET. Results indicated, before and after infrared radiation, there are no significant changes in the state of γ-Al2O3 and bentonite samples. According to the results of BET and SEM analyses, due to the higher surface areas of γ-Al2O3 and Bentonite than α-Al2O3, they have more active sites. Results also indicated that the caking of the sample particles occurs less frequently.