Multi-objective optimization design of solar air collector with a frustum-shaped protrusion

Abstract

The artificial convex is arranged on the absorber plate of a solar air collector can significantly improve the solar utilization efficiency. The heat transfer efficiency is determined by the geometric types of protrusion and its arrangement in the heating channel. In this study, four parameters, the height and gap of the protrusion structure, the arrangement spacing of the V-shaped structure, and the airflow attack angle are considered to reflect the effect of protrusion on fluid flow and heat transfer characteristics in the solar air collector. Considering the interactive coupling relationship among various structure and location parameters, taking the maximum average Nusselt number, minimum friction coefficient, and maximum comprehensive heat transfer coefficient (THPP) as the objective functions, the Response Surface Method (RSM) is adopted to comprehensively analyze the impact of multiple factors on the thermal efficiency of solar air collector, and thus obtains the optimal design parameters of solar air collector with the optimal comprehensive performance. Comparing with the univariate method, the THPP value of the optimized structure by RSM is 3.6% higher than that by the univariate method. The value of thermal efficient of the optimized structure by RSM is 26% higher than that of the smooth plate solar air collector. When the Reynolds number is higher than 10000, the value of thermal efficient of the optimized structure by RSM is much higher than those of the published references. In addition, the contribution of different influencing factors to improving the comprehensive performance of solar air collector was obtained, which is meaningful for providing theoretical basis for engineering optimization design.