Chapter 7 - Active Solar Systems in Buildings

Abstract

This chapter deals with the review of solar active thermal systems. They are discussed from a point of view of different technological concepts, mode of operation, heating needs, complexity of their design, and construction. Different classifications of these systems are also presented. The focus is put on system configuration depending on its heating functions. Some consideration is given to the structure of solar heating systems, methods of energy storage, and cooperation with alternative, auxiliary, or peak heat sources, including heat pumps. Flat-plate, evacuated tube, unglazed, and some other types of solar collectors and their main components are described. Advantages and disadvantages of the main types of solar collectors are analyzed. Methods of determining energy efficiency of solar collectors and graphical interpretation of their thermal characteristics are presented in order to show how different collector types can be evaluated for their use in buildings in different weather conditions and applications. Use of photovoltaics (PV) in buildings is also considered. Physical fundamentals of the internal PV effect are presented. Technologies of solar PV cells and systems are described along with different operating modes. The stress is put on technologies applied in buildings. It is emphasized that the dual nature of building elements, with coherency between architecture and energy production (PV systems and solar heating), will be standard in solar self-energy sufficient buildings. To give a full picture of solar active systems applied in buildings, solar cooling technologies are also discussed. It is underlined that sorption cooling technologies may help in solving a problem of working fluid overheating in the collector loop and in storage encountered in solar combisystems (i.e., space heating plus hot water heating).