Thermal analysis of a flat-plate solar collector filled with water under the dynamic operation via a multiparameter sensitivity analysis utilizing the Monte-Carlo method

Flat-plate solar collectors (FPSC) are commonly used for low-temperature heating applications, making system modeling and sensitivity analysis crucial. However, most sensitivity analyses for these collectors are conducted under steady-state conditions. Because of the inherently dynamic nature of ambient conditions, dynamic modeling and sensitivity analysis are needed to better understand and determinate important influencing design parameters. This study presents a comprehensive parametric analysis using a dynamic model of the solar flat-plate collector. The impact of deviations from nominal values of each parameter on system performance and final storage tank temperature is investigated. The findings reveal that pitch tube and absorber thickness significantly influence system efficiency, with a 20% deviation in each parameter resulting in a 10% efficiency change. Moreover, ambient temperature and irradiance have a high impact, causing changes of over 10%. Additionally, a multiparameter sensitivity analysis utilizing the Monte-Carlo method (MPSA) is employed to assess the relative importance of each parameter on FPSC performance. The results highlight that system efficiency is highly sensitive to absorber thickness, while tube pitch, ambient temperature and solar irradiance are crucial for tank temperature. The MPSA is further applied across various ambient temperatures (ranging from 5 to 35 degrees) to determine changes in parameter sensitivity indices. The outcomes indicate that at lower ambient temperatures, certain parameters, such as solar irradiance and tube pitch, exhibit increased sensitivity. However, the sensitivity of system efficiency to all parameters remains relatively constant across different ambient temperatures.