Heat transfer mathematical model for a novel parabolic trough solar collecting system with V-shaped cavity absorber

Solar heat utilization in medium temperature range (80-250℃) has attracted more and more attentions in the field of building and industry energy conservation. A heat transfer model for a novel parabolic trough solar collecting system with V-shaped cavity absorber is established based on the thermal resistance network method. Experimental validation was performed in different weather conditions to investigate the calculation accuracy of the proposed model. The analysis results demonstrate that the model calculation error mainly lies in the influence of wind speed deviation and the difference between the theoretical and actual temperature rise rate with the sudden changes of solar direct normal irradiation (DNI). By carrying out bias correction, the model calculated results were perfectly consistent with the experimental results. Based on the proposed model, the effects of different environmental factors on the outlet temperature and collecting efficiency were compared, and the comparison results can be used to correct the proposed model in different weather and environmental conditions, which make the proposed heat transfer model more reliable to the practical operation situation. As a result, the proposed model may provide a theoretical basis for the operation optimization of the solar collecting system.