ABSTRACT
The use of solar energy for heat production dates from antiquity. Historically, methods used for collecting and transferring solar heat were passive methods, that is, without active means such as pumps, fans, and heat exchangers. Passive solar heating methods utilize natural means such as radiation, natural convection, thermosyphon ow, and thermal properties of materials for collection and transfer of heat. Active solar heating methods, on the other hand, use pumps and fans to enhance the rate of uid ow and heat transfer. Active methods for water heating, space heating, and industrial process heat (IPH) have been developed mainly in the last four decades. This chapter describes in detail the function and design of active systems for heating buildings and service water. Passive solar heating, cooling, and daylighting are covered in Chapter 7. Other applications, such as low-temperature solar heat for agriculture, agricultural drying, or aquaculture, can be analyzed with the principles set forth in this chapter and Chapters 3 and 4.
