Enhancement of heat transfer utilizing small height twisted tape flat plate solar heat collector: A numerical study

Abstract

The flat plate solar heat collector captures solar thermal energy for agricultural drying, heating houses and businesses, cooling food, and producing steam. Adding twisted tape inserts to the absorbent surface of a flat plate solar heat collector increases its efficiency. This article describes the absorber plate of twisted tape inserts and discusses the thermal and hydraulic performance achieved by varying the twist pitch and twist height. Computational fluid dynamics is performed for Reynolds numbers ranging from 5000 to 17000, relative twist height (TH/Dh) of 0.011-0.044, relative twisted tape inserts pitch (PTT/TH) of 49.95-73.2 and relative twist pitch (TP/TH) of 8-15. Heat transmission and friction factors owing to twisted tape inserts have been analyzed in depth using computational fluid dynamics, with analysis performed using the k-epsilon model in commercial ANSYS Fluent 19.2 software. A maximum thermal-hydraulic performance value of 2.41 is observed for the many twisted tape parameters, with, TH/Dh of 0.022, PTT/TH of 64.60, and TP/TH of 12.

Keywords

• CFD
• Solar energy
• Thermohydraulic performance
• Twisted tape
• Turbulent flow