Experimental and theoretical evaluation of dynamic test procedures for solar flat-plate collectors

This communication presents a critical evaluation of nine dynamic test methods for solar flat-plate collectors. The theoretical basis, the technique of parameter estimation and the test procedure of each method have been reviewed and compared. Extensive experimental studies have been carried out under a wide range of weather and operating conditions. Two commercially available collectors (from two different manufacturers) have been used in the investigation. The tests were carried out at the same location using a common test-rig, measuring transducers and controlling and data-acquiring facilities. The characteristic parameters of the collectors have been obtained on the basis of each procedure and compared with those based on the steady-state ASHRAE 93-86 standard. Further, for the methods which prescribe similar test sequences, the collector parameters have been extracted from the same data sets according to their procedures for providing a direct and very clear comparison between the methods. A sensitivity study has also been carried out in order to examine the effect of uncertainties in measurements on the values of the estimated parameters from different methods. Also investigated is the error propagation wherever applicable. Among the methods evaluated, the new dynamic method (NDM) seems to be quite reliable. The quick dynamic test (QDT) method is the most simple method and could be adopted by manufacturers as an effective tool for the purpose of quality control of their products. From the point of view of theoretical completeness, Perers' method accounts for almost all effects. (C) 2000 Elsevier Science Ltd. All rights reserved.