Experimental Study on the Heat Transfer Characteristics of an Inclined Shell-and-Tube Phase-Change Thermal Energy Storage Unit

Detailed experimental investigation is presented for the heat transfer characteristics of an inclined shell-and-tube phase-change thermal energy storage unit. For the case of inclined angle alpha = pi/4, the solid-liquid interface presented a concave surface because the heat transfer can be affected not only by conduction in the phase-change material (PCM) domain but also by natural convection significantly. The heat transfer rate increases with the increasing flow rate and inlet temperature of heat transfer fluid (HTF), but the flow rate of the HTF has little effect on the charging process for the case of q(v) >= 40 L/h. The heat transfer rate of PCM above the HTF tube increases with the increase of inclined angle. The effects of inclined angle on the heat transfer rate can be not negligible due to the obvious natural convection in the charging process.