Investigation on performance of an asphalt solar collector: CFD analysis, experimental validation and neural network modeling

• Published in: Solar energy 2020-09, Vol.207, p.703-719
• Main Authors: Masoumi, Amir Pouya, Tajalli-Ardekani, Erfan, Golneshan, Ali Akbar
• Format: Article
• Language: English
• Subjects: Absorptivity; Artificial neural network; Artificial neural networks; Asphalt; Asphalt solar collector; Boundary conditions; CFD simulation; Computational fluid dynamics; Computer applications; Design parameters; Flow rates; Flow velocity; Galvanizing; Heat transfer; Mathematical models; Neural networks; Numerical models; Parallel connected; Performance evaluation; Renewable energy; Solar collectors; Solar energy; Temperature gradients; Thermal conductivity; Thermodynamic efficiency; Water flow; Water temperature
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2020.06.045

•An asphalt solar collector is simulated by a novel CFD model.•Several experiments are carried out to validate the numerical results.•An artificial neural network model is developed to predict the performance of the system.•Effective parameters in the variation of the outlet water temperature and efficiency are discussed. This paper presents a numerical model, development, and experimental validation of an Asphalt Solar Collector (ASC) which subsequently is modeled by Artificial Neural Network (ANN). In this research, 2 m long galvanized pipes are connected in parallel and embedded into an asphalt slab with 1 m2 area. The slab is buried in the ground to have thermal heat transfer with adjacent soil and to resemble real conditions. Several experiments are carried out in both warm and cold months of the year with different water flow rates from 9:00 to 17:00. The ASC is modeled with CFD techniques and the desired parameters effect are independently studied based on a reference condition. An ANN model is proposed to expand the parametric study and reduce the high computational cost of numerical modeling. The inputs of the ANN include the design and the operating parameters and the outlet water temperature is considered as the output. These models are capable of evaluating the performance of the ASC at every hour during the day and under different boundary conditions. The parametric study shows that improvement of surface absorptivity and thermal conductivity of asphalt leads to a higher increase of the daily efficiency in August, however, the inlet water temperature has the same effect in November. The maximum water temperature difference and the thermal efficiency of the ASC can reach up to 24 °C and 45% in August and 14 °C and 35% in November respectively.