Fundamentals of Solar Energy

This chapter is concerned with the availability of solar radiation as an energy source the nature of the radiation emitted by the sun and the incident on the Earth’s atmosphere. Extra-terrestrial radiation on a horizontal surface, its spectral distribution [i.e., we will be concerned primarily with radiation in a wavelength range of 0.25 to 3.0 μm, the portion of the electromagnetic radiation that includes most of the energy radiated by the sun] and the radiation at the earth’s surface is discussed first. The second major topic in this chapter is solar radiation geometry that is, the direction from which beam solar radiation is received its angle of incidence on various surfaces and the quantity of radiation received over various time spaces. Various angles are also defined so that it is possible to convert the flux on one plane to an equivalent flux on another. Why solar radiation data is needed? What are the proper ways to achieve the solar radiation data? Instruments for measuring solar radiation and methods for presenting data are then described. Empirical equations for predicting/Estimating the availability of solar radiation at a location have been finally discussed.