Measurements of Typical Insolation Variation at Daggett, California. Volume I. Methodology and Sample Data

摘要

Observations of insolation variation for a site representative of the Ten-Megawatt Solar Thermal Pilot Plant (approximately 600 meters in size) were made at 16-second intervals for the period from August 1978 through October 1979 at a location near Barstow, California. The analysis of data from this experiment is reported. Insolation variations over the experiment site indicate partly cloudy conditions existed approximately 25 percent of the time for the one-year experimental period. During these partly cloudy periods, shadows with dimensions less than the pilot plant heliostat field size were observed. Rates of insolation change greater than 30 W/m exp -2 sec exp -1 were also observed; however, these observations were limited by the sampling rate of the experiment. A procedure was developed to interpolate to any point within the experiment array by means of insolation variation maps. Detailed data packages are supplied for eight days that were determined to be typical of the different partly cloudy conditions observed during the year. These measurements indicate that variations are much more severe than were originally assumed in the derivation of the Ten-Megawatt Solar Thermal Pilot Plant operating requirements. (ERA citation 81:025224)