Line focus solar thermal central receiver research study. Final report, April 30, 1977-March 30, 1979

The results of a study to examine the line focus central receiver alternative for solar thermal generation of electric power on a commercial scale are presented. The baseline concept consists of the following elements: (1) a solar collector (heliostat) whose geometry is the equivalent of a focused parabolic cylinder. The heliostat reflecting surface is composed of an array of flexible rectangular mirror panels supported along their long edges by a framework which rotates about an axis parallel to the ground plane. The mirror panels in one section (18.3 meters by 3.05 meters (60 feet by 10 feet)) are defocused in unison by a simple mechanism under computer control to achieve the required curvature. Two sections (110 meters/sup 2/(591 feet/sup 2/)) are controlled and driven in elevation by one control/drive unit. (2) A linear cavity receiver, composed of 61-meter (200-foot) sections supported by towers at an elevation of 61 meters (200 feet). Each section receives feedwater and produces turbine-rated steam. The cavity is an open cylinder 1.83 meters (6 feet) in inside diameter, with a 1.22 meter (4 foot) aperture oriented at 45 degrees to the collector field. (3) Heliostat control, consisting of a local controller at each heliostat module which communicates with a master control computer to perform elevation tracking and focal length adjustment. The control logic is open-loop, with sun position computer by the master computer with an algorithm. Image sensors, mounted above and below the receiver aperture, are used to monitor the collector field and provide feedback to the master computer for detection of misaligned heliostats. (WHK