Low Temperature Systems for Buildings

Although the solar collector is the key component in a solar thermal system, depending on the temperature range needed and the heat transfer fluid found useful for this, many other system components like controls, pumps, heat exchangers, valves etc. are needed. When we investigate the application in buildings, room heating and hot water are the dominant applications, both restricted to a low temperature range up to 60 °C. The solar cooling and climatization of buildings are a rather special application which needs higher temperatures in the collector circuit, therefore it is treated in a separate Chap. 13 . A large variety of system concepts are found nowadays, with passive and active heat transport to the consumer, which are described after a classification in this chapter. The components of a collector circuit are described and specified. The planning and dimensioning of a solar thermal collector systems has many aspects and can use simple rule-of-thumb design, but generally utilizes numerical simulation tools, where the time series of temperatures and heat flows in a solar thermal system are modelled for all individual components. These design rules and the use of simulation tools are detailed in the last sections of the chapter.