Solar Engineering of Thermal Processes, 4th Edition

Chapter 9

Solar Process Loads

The supply of solar energy from a collector is time dependent. In general, loads to be met by an energy system are also time dependent. Energy storage, as outlined in the previous chapter, provides a buffer between these two time-dependent functions. In Chapters 6 and 7 we discussed calculation of collector output. In this chapter, we outline briefly the common methods for calculating some common loads and provide references which will provide much more detailed information.

The term load, as used here, refers to the time-dependent energy needs which are to be met by an energy system.¹ The system will generally be a combination of a solar system and another system, the auxiliary, or backup, system. We designate the total load as , that part that is supplied by solar energy as , and that by auxiliary as . These loads will usually be integrated over some time period, such as an hour or a month. (Load rates in this chapter are identified by ; in later chapters where the distinction between rates and integrated loads is clear, the dot will not be used.) There ...