Assessment of thermofluidic behaviour of a Medium-High-Temperature shell and tube latent heat storage through experimental and computational investigation

The study envisages a holistic experimental methodology encompassing the entire spectrum of formulation, characterization, and thermal response evaluation of a medium–high-temperature (MHT) phase change material (PCM). The heating rate in melting is significantly less than the cooling rate during solidification until PCM reaches phase transition temperature. For q“ = 1000 W/m², charging duration of vertical domain (θ = 90°) is 15 % slower than horizontal domain (θ = 0°). However, with increase in flux to 2000 W/m² the charging duration is only 6 % slower for θ = 90° than θ = 0°. Melting/charging duration for thermocouple positioned at A (r = 18 mm, top side of prototype) is 15.38 % lower than at F (r = 18 mm, bottom side of prototype) and positioned at C (r = 38 mm, top side) is 8 % lower than at D (r = 38 mm, bottom side) for horizontally orientated LHTES system. A substantial decrease (by 17.64 %) in discharging duration was observed with increase in the inlet flow rate and the inlet temperature by 2.5 times and 3.3 times, respectively. The total energy accumulated in the LHTES demonstrates an approximately 11 % increase with the escalation of electric flux from 1000 W/m² to 2000 W/m² during the charging process for θ = 0° orientation. In contrast to charging, faster solidification rate is observed in the bottom half of the prototype (points D, E, F) compared to the top half (points A, B, C) which has implications for the design and operation of LHTES systems.