Design and Thermo-Fluid Dynamic Evaluation of a Solar Air Collector with Serpentine Absorber Under High-Andean Conditions in Puno

Abstract

This work proposes the geometric design and material selection of a box-type solar air collector, oriented to high-Andean conditions (Puno, Peru). The system incorporates an internal tubular serpentine that conducts the air flow in parallel passes, prioritizing manufacturability criteria (commercial tube, separation tolerances, and return radii) and thermal performance. The methodology integrates a first-order model based on energy balance, estimation of optical gain via (τα), and quantification of losses due to conduction, convection (internal and external), and radiation, employing standard correlations to obtain the convective coefficient. As a result, the final dimensions of the collector and the serpentine (number of passes, total length, and exchange area) are defined, together with relevant thermo-fluid parameters (Re,Nu, hi, and UA) for representative irradiance and flow rate scenarios. The design remains ready for its implementation and CAD documentation (SOLIDWORKS) and for a subsequent experimental validation under real conditions.