Landolt-Börnstein - Group VIII Advanced Materials and Technologies
4.3 Nonfocusing solar heat collection (incl. seasonal heat storage)
This chapter provides an overview of the basics of nonfocusing solar heat collection and solar thermal energy use with non focusing systems, the system engineering and the different technical possibilities. Beyond that practical guidance for plant design, a description of individual large scale projects is included. With regard to the operation temperature, the thermal use of solar energy can be subdivided into three categories: low, medium and high temperature applications. The main components of low temperature applications are the collectors. Due to lack of coincidence between the supply of solar energy and the heat demand, most thermal solar plants require heat storage. It would be ideal to store energy from the summer up to the winter times (seasonal heat storage). The tanks consist of high-grade, enameled or plastic coated steel. In a double circuit solar plant for domestic hot water (DHW) preparation, a storage tank with two heat exchangers is the usual solution. A system works satisfactorily only when the system configuration is adjusted to basic site conditions (local weather data and the amount and time profile of the DHW-demand) and if all components are well suited to each other. Common types of systems are thermosyphon and forced circulation systems. For the testing and development of collector and system technology, a number of large-scale solar plants with short-term storage have been built in the last years. The chapter lists the first realized plants and provides project examples. European market development of solar thermal plant is briefly discussed.