Novel absorptive coatings are necessitated so as to have enhanced absorption of solar radiation and also enhanced heat transfer to working fluid in solar collectors. In this connection, the present investigation was devoted for the (i) preparation and deposition of nano-carbon and aluminum oxide mixed coating on absorber (ii) characterization of the prepared coating and (iii) estimation of thermal enhancement not only in solar absorber but also in the working fluid used in the solar collector. While standard methods were adopted for the preparation of nano-carbon and Al2 O3 based absorptive coatings, the spray coating method was adhered for the deposition. By using Scherrer formula, the size of the particles in coating was calculated and it was found to be 65.90 nm. The micro strain was also calculated and it was found to be 0.526 x 10-6. It could be concluded that copper absorbers with nano-carbon and aluminium oxide based coatings would be utilized in solar collectors not only to have enhanced absorptance of solar radiation but also to have enhanced thermal performance of solar collectors.
