Effect of metal foam on PCM melting dynamics at different heated surface inclinations

Thermal energy storage systems have gained significant attention in recent years due to their potential to improve energy efficiency and sustainability in applications like solar thermal energy and building temperature regulation. Phase change materials (PCMs) are attractive for such systems due to their high energy storage capacity and temperature stabilization properties. However, the performance of PCM systems can be influenced by factors like surface orientation, which affects heat transfer mechanisms. This experimental study examined the effect of heated surface inclination on the thermal performance of phase change material (PCM) systems, comparing pure PCM and PCM enhanced with metal foam. A rectangular enclosure with an adjustable tilt was used. All the tests were conducted at a heat flux of 8 kW/m 2 and an inclination varying from 0° (vertical) to 20°. For pure PCM, increasing the tilt angle improved natural convection, leading to more uniform melting and lower surface temperatures. With metal foam, thermal conductivity increased up to 7 times compared with pure PCM, resulting in a more uniform heat distribution that is less affected by orientation. These findings offer valuable insights for designing efficient thermal management and energy storage systems. Optical flow results from the melting front behavior for the vertically heated surface and with a tilt angle of 20°. • Metal foam increased effective thermal conductivity up to 7×, enhancing energy storage; • Heated surface inclination boosted convective melting and heat transfer rates; • Optical flow captured the melting front dynamics and velocity field evolution; • Inclined walls increased melting front velocity by 36% (10 PPI) and 21% (15 PPI); • Foam-based PCM uniformizes temperature fields, reducing gradients and thermal stress.