Performance of a rigid porous-tube stratification manifold in comparison to an inlet pipe

•Thermal stratification during top and intermediate charging was measured.•Exergy efficiency and PIV flow measurements are presented.•The porous tube outperformed an inlet pipe and diffuser for intermediate charging.•The porous tube performed on par with a diffuser for top charging.

Achieving thermal stratification of storage tanks has well documented advantages for increasing the efficiency and quality of delivered energy of solar heating systems. The present work presents experimental characterization of a porous tube manifold during charging of a water tank at 0.07 kg s−1. Measurements of vertical temperature distributions are used to evaluate the dimensionless exergy efficiency of the manifold in comparison to a top-mounted inlet pipe and an inlet pipe with a diffuser. Particle image velocimetry measurements illustrate the fluid dynamic behavior of the three inlet configurations. Results demonstrate that the manifold is superior to the other inlet configurations studied. It releases the incoming flow at the level of neutral buoyancy, and prevents suction of tank fluid into the manifold at other vertical levels.