Preparation, characterization and assessment of solar harvesting performance of spectrally selective nano black coating

The solar collector efficiency is highly dependent on the characteristics of selective coating absorber surface; therefore, in this work, the electrochemical engineering technology is utilized to oxidize the aluminum surface to give a porous layer with diameters of nano-size, aluminum strips were anodized via anodic oxidation and then nano metal ions were electrochemically deposited imparting uniform black color. The morphology of the surface of anodized aluminum samples was investigated by SEM and AFM analysis. Also, one of the most important applications of the current study, is the coupling of the black colored aluminum as absorber plates in solar thermal energy systems. The present work solar collector (PWSC) has been successfully designed and compared with similar area commercially available solar collector (CASC). The PWSC recorded higher water outlet temperature (up to 60 o C) than that of the CASC (up to 49 o C) for the same water inlet temperature. The CASC thermal efficiency parameter, FR(τα)e, equal 72.67% and thermal heat loss parameter, FRUL, equal 26.478 while the PWSC recorded thermal efficiency parameter, FR(τα)e, 79.4% and thermal heat loss parameter, FRUL, 17.408 therefore, using selective coating in the absorber plate increased the collector thermal efficiency by 10%. The efficiency of the solar collector is therefore increased by optimizing the thermal energy input and reducing the quantity of heat loss to the environment. The present work solar collector (PWSC) has been successfully accomplished and investigated to give the best performance.