Solar Plant

equipment for converting solar radiation energy into other convenient forms (for instance, thermal or electrical energy).

Solar plants are made with and without concentrators. The former convert the solar radiation energy after its intensity has been increased by a solar concentrator; the latter do so with the natural intensity. Distinctions are made between types on the basis of the purpose, the concentrator used, the nature of the conversion process, and other attributes or combinations of attributes; the types include thermoelectric generators and solar water heaters, solar furnaces, solar batteries, and solar power plants, among others.

Solar plants without concentrators are used for such purposes as heating water or air, distilling water, obtaining electrical power, and drying fruits, vegetables, and materials. The majority of these plants operate on the “hot box” principle.

Plants with concentrators are used to obtain high temperatures for “sterile” technological conditions. Their efficiency is usually not greater than 0.4 to 0.6. Parabolic, approximately parabolic, and parabolic-cylindrical mirrors are most frequently used to concentrate the solar rays. Because of the complexity of their manufacture, lenses, conical mirrors, and other types of mirrors are seldom employed.

Paraboloidal solar plants with an accurate concentrator can achieve temperatures up to 3600° C. At this temperature practically all metals and refractory materials are melted. The high-efficiency types are utilized in combination with various solar radiation receivers, such as high-temperature furnaces, thermoelectric generators, thermoionic converters, and steam boilers. Approximately parabolic plants can be used to obtain steam for industrial applications such as combined power and heating and to produce electrical power, distilled water, cooling, and so on. With parabolic-cylindrical plants it is possible to obtain steam at a pressure of 0.2 to 0.4 meganewtons per sq m (2 to 4 kilograms-force per sq cm) for distilling water, processing food in autoclaves, and other purposes.