Flat Plate Collector with Plane Reflectors: In this a flat plate collector with adjustable mirrors at the edges to reflect radiation on to the absorber plate and is as shown here. Fig : Flat Plate Collector with Plane Reflectors arrangement It is simple in design. The value of the concentration ratio of the flat collector is above unity and. In this type of collector, the concentrator consists of curved segments which are two parts parabolas. In this, the concentration ratio ranges from 3 to 10. In this the image is formed on the focal axis of the parabola Concentration ratio between 10 to 80 and suits temperature between 150° to 400 CIn this concentrator has to rotate to track the. In this lens is mainly fabricated flat on one side and with fine longitudinal grooves on the other. The angles of these grooves are such that radiation is. In this, it has a moving receiver and a fixed concentrator. The concentrator is like an array of long and narrow, flat mirror strips fixed along a cylindrical surface. Fig: Collector with fixed circular.