Design and experimental investigation of stainless-steel based chevron-hydroformed manifold of evacuated heat pipe solar collector

A manifold is an essential component of an evacuated tube heat pipe solar collector (ETHPSC) that directly influences the thermal efficiency of a solar heating system. This study aimed to develop and assess the use of a stainless-steel based chevron-hydroformed manifold in ETHPSCs as an alternative to conventional copper-based welded manifolds, which have a high manufacturing cost and short life span and are easily corroded. In the present study, the physical design of the proposed chevron-hydroformed manifold was elucidated. Numerical simulation using computational fluid dynamics was performed to characterize the hydrodynamic behavior of fluid flow through the chevron-hydroformed channels. The thermal characteristics and frictional pressure drops of a smooth-hydroformed and a chevron-hydroformed manifolds were experimentally investigated. The experimental results showed that the convective heat transfer coefficient of the chevron-hydroformed manifold was greater than the smooth-hydroformed manifold by approximately 29.0 %. However, the proposed chevron pattern of the proposed hydroformed manifold resulted in a larger pressure drop compared to the conventional manifold by approximately 17.7 %. Field experiments were conducted to compare the performance of the stainless-steel based chevron-hydroformed manifold with that of a conventional copper-based welded manifold. The feasibility of employing the stainless-steel based hydroformed manifolds in ETHPSCs in solar heating applications was examined.