ABSTRACT
This chapter reviews the necessary fundamentals related to the underlying principles involved in harvesting solar–thermal energy using optical reflector and spectrally selective absorber materials. Capturing the solar energy using technologically feasible approaches and harvesting it have been the central paradigm of renewable energy generation. The spectral distribution in solar spectrum depends on the atmospheric conditions. Quantification of solar radiation is performed by determining the solar constant, which represents mean incident irradiation passing an unit cross-sectional area. Electromagnetic waves with different wavelengths have respective frequencies. Interestingly, a specific color can be represented by a distinct frequency in the visible spectra. When electromagnetic radiation (e.g., solar radiation) incidents on the surface of any material, internal electric and magnetic fields are generated due to the presence of electric charges inside the material.
