Solar Energy, Vol.204, 406-418, 2020
Comparison of different dynamic thermal performance prediction models for the flat-plate solar collector with a new V-corrugated absorber
The flat-plate solar collector with a V-corrugated absorber (VFPC) has been shown to be able to improve the steady-state optical and thermal efficiency by up to 15.8% and 10.7%, respectively. To predict the dynamic thermal performance of VFPC, the Quasi-Dynamic Test Model (QDTM), Transfer Function Model (TFM) and Dynamic Heat Transfer Model (DHTM) are compared in this study. The coefficients of the dynamic test models (including QDTM and TFM) are obtained by the regression of experimental data, and the DHTM is presented based on the analysis of detailed heat transfer processes inside collector. Tested data under four kinds of test conditions is selected to identify parameters in the dynamic test models, and tested data under one more test condition with varied solar irradiances, fluid inlet temperatures and mass flow rates is selected to validate the prediction accuracy of the three models. For the short-term prediction results by QDTM/TFM/DHTM, the maximum absolute value of relative error of fluid outlet temperature T-fo and rate of useful heat gain Q(u) are 6.8%/5.5%/3.0% and 64.9%/43.8%/29.6% respectively. While for the long-term prediction results with the operation period of about 1 h, the averaged absolute value of relative error of useful heat gain Q(u.o) are 1.4%/1.0%/1.2% and the averaged absolute error of averaged thermal efficiency eta(t.o) are 1.1%/0.8%/0.9%. Results indicate that the DHTM has the most potential to predict the short-term thermal characteristic of VFPC accurately, followed by the TFM and QDTM, while the three kinds of models have the similar accuracy level to predict the long-term thermal characteristic of VFPC.