Chapter 2 - Nanomaterials for solar energy capture and steam generation

Solar energy is the most abundantly available renewable energy source which can be utilized by converting it into electrical energy or thermal energy. Photothermal conversion is the easiest and most convenient way to exploit solar energy. Solar collectors are used for this purpose where solar radiation is absorbed on an absorbing plate and the resulting heat is transferred to the working fluid by convection, with this process being described as the conventional method of solar collection. Instead of an absorber plate, solar radiation may directly be absorbed by the working fluid, thereby minimizing one step of heat transfer, and this process of solar collection is called direct absorption solar collection, which is an emerging technique for efficient harnessing of solar thermal energy. This chapter details some of the novel nanomaterials and the underlying mechanisms used to enhance solar absorption and thus the efficiency of direct absorption solar collectors (DASCs). These novel nanomaterials are broadly categorized as plasmonic, carbon-based, and hybrid nanomaterials for efficient solar photothermal collection in DASCs. Potential challenges and prospects of these emerging nanomaterials are also presented at the end of the chapter.