Uncertainty analysis and experimental validation of solar parabolic trough collector simulation model

Abstract

The scope of this study is to present a novel methodology for the validation of a solar parabolic trough collector simulation model, developed in System Advisor Model software, using solar field thermal performance experimental model functions that duly account for the contributions of errors that are inherent in the collection of input experimental data. The study focuses on the uncertainty associated with the predicted thermal energy output and thermal efficiency, which were calculated by using standardized testing procedures that were developed by the National Renewable Energy Laboratory and the American Society of Mechanical Engineers. Errors due to imperfections of the experimental models used throughout the test are also counted in, as well as uncertainties attributed to the variability of meteorological conditions. The experimental tests were conducted under clear-sky and steady-state conditions in Kenya, using a prototype parabolic trough collector. The uncertainty analysis provided a realistic evaluation of the thermal performance of the prototype during testing, resulting in expanded uncertainties of 9.05% (0.104 kWhth) for thermal output and 3.66% (0.0258) for thermal efficiency. Notably, the predicted thermal output and thermal efficiency from the experimental models did not exceed observed levels, demonstrating a strong correlation between predicted and observed values, supported by R2 regression coefficients of 0.972 for thermal output and 0.989 for thermal efficiency. The comparison of the two experimental model results with the simulation outcomes validated the performance of the simulation model, as the simulation results fell within the experimental error margins. Additionally, the statistical analysis yielded significant results, with root mean square error, mean bias error, and t-statistics values for thermal energy output of 0.057, 0.033, and 2.135, respectively, and for thermal efficiency, 0.018, 0.010, and 1.993, respectively, indicating the accuracy and reliability of the simulation model. Thus, the simulation model has been successfully validated, proving its capability to accurately predict the thermal output and efficiency of the parabolic trough collector.