Performance Analysis and Design Optimization of a Mini-Channel Evacuated-Tube Solar Collector

Abstract

The utilization of renewable energy sources is receiving considerable attention as a non-resource-depleting approach that reduces the emissions of pollutants and green-house gases to the atmosphere. Solar thermal systems have the capability to provide heat in a sustainable way for a variety of applications due to the relatively large range of temperatures that different collector configurations can attain. Most evacuated-tube solar collectors currently found on the market consist of a u-shaped round tube, concentric round tubes in counter flow regime, or a heat-pipe. The external surface in these designs is welded to a thin absorber fin that is covered with a selective coating. This paper analyzes the performance of an evacuated-tube solar collector that contains a U-shaped mini-channel tube. Comparisons of performance with respect to standard u-shaped round-tube solar collector are made. The design of a mini-channel based solar collector without absorber fin is also analyzed and its performance optimized with respect to its geometrical parameters.