Experimental investigation of melting behaviour of phase change material in finned rectangular enclosures under different inclination angles

•Solid-liquid interface evolutions are visualized during melting of PCM in finned inclined enclosures.•Melting rate increases by reducing the inclination angle.•The maximum reduction in melting time obtains by the 3-fin horizontal enclosure.•Vortical flow structures appear during melting in the horizontal enclosure.•Decreasing the inclination can be more effective to enhance the melting rate than adding fins.