An improved model for predicting the performance of parabolic trough solar collectors

Abstract

Summary An improved solar parabolic trough collector model has been developed in this study, to overcome the weakness of the previous published studies in predicting accurate performance, at higher operating temperatures. To check the accuracy of the proposed model, both on‐sun and off‐sun tests have been considered. The on‐sun tests are aimed to check the potential of the model for predicting the thermal efficiency while off‐sun tests are for heat losses. The results have indicated that the efficiency uncertainties of the present model are lower than those obtained during the experimental tests of Sandia National Laboratory for all the cases. When compared with previous published models, the proposed model is ranked first, more accurately than those of NERL, Garcia, and Behar. An average uncertainty of less than 0.50% has been obtained while Behar's model show less precision with a deviation of more than 0.55%. The models of Forristall and Garcia‐Valladares have been ranked third and last respectively, with absolute uncertainty of 0.782% and 1.202%. The evaluation of the accuracy of the model in predicting the heat losses have been carried out based on 7 test cases of different ambient conditions. At higher operating temperatures, the present model has shown significant improvements. At 350°C, the model has shown an uncertainty similar to that of experimental tests, ie, 7.3 W/m2. Moreover, it has been ranked first with an average deviation of 3.42 W/m2, more accurate than those developed by Behar, Garcia, and Forristall. If the glass of the solar receiver is broken during operation, the present model might offer some knowledge about their performance. Indeed, the model has also been checked for predicting the thermal performance of PTC with air in the annulus of solar receivers. The RMSE is found to be less than 1.5% for the case of efficiency during on‐sun tests, and values of 2.292% and 1.562% have been obtained for Garcia‐Valladares and Forristall models. Similar finding has been observed for the case of heat losses. Therefore, the proposed model might be an accurate tool for parabolic trough collector performance predictions.

Thermal and Geometrical Assessment of Parabolic Trough Collector Mounted Double Evacuated Novel Receiver Tube System

“…Similarly, Odeh et al (1998) used direct steam generation over an indirect steam generation in a PTC system and the system performance was calculated with the help of an equation. Agagna et al (2018) predicted the accuracy and performance of the system by comparing their PTC model with an existing system while the results reported about 0.5% of uncertainty in the predicted performance where results were reported to be reliable. The study revealed that the system achieved maximum performance when the rim angle was 68 o .…”

Effect of receiver geometry on the optical and thermal performance of a parabolic trough collector

“…Maximum exergetic efficiency was recorded for liquid sodium. Agagna et al 17 proposed a user‐defined function built in a finite volume model to minimize the need to use a tracing model to investigate the thermal performance of a parabolic trough collector with a circular receiver. The results from the proposed model were validated with experimental data.…”

Coupled optical and thermal analysis of large aperture parabolic trough solar collector

“…The effect of various parameters on the thermal performance of the PTSC has been studied such as solar radiation, heat transfer fluid (HTF), mass flow rates and fluid inlet temperature 15,23 . Agagna et al 39 provided an improved model for analysing the thermal efficiency of PTSC. Some researchers also investigated the performance of large aperture PTSC 35,40‐44 .…”