INFLUENCE OF MEASUREMENT EQUIPMENT ON THE UNCERTAINTY OF PERFORMANCE DATA FROM TEST LOOPS FOR CONCENTRATING SOLAR COLLECTORS

Abstract

Parabolic trough concentrating collectors play a major role in the energy efficiency and economics of concentrating solar power plants. Therefore, existing collector systems are constantly enhanced and new types developed. Thermal performance testing is one step generally required in the course of their testing and qualification. For outdoor tests of prototypes a heat transfer fluid loop (single collectors or entire loop) needs to be equipped with measurement sensors for inlet, outlet and ambient temperature as well as irradiance, wind speed and mass or volumetric flow sensors to evaluate the heat balance. Assessing the individual measurement uncertainties and their impact on the combined uncertainty of the desired measurement quantity one obtains the significance of the testing results. The method has been applied to the EuroTrough collector tests performed at PSA. Test results include the uncertainty range of the resulting modeling function and exemplify the effects of the sensors and their specifications on the parameters. Recommendations for suitable sensor types and classes as well as the required number of sensors and their location are given on the basis of experience gained during tests of concentrating collectors.