Experimental investigation of variable fin length on melting performance in a rectangular enclosure containing phase change material

The present study proposes a new technique to determine liquid fractions of phase change material during the melting process in a left-side heated rectangular enclosure. The effects of variable fin length arrangements on the melting performance of phase change material (PCM) were also investigated experimentally. Detailed information about solid, mushy, and liquid ratios was obtained by analysing the temperature histograms of real thermal images of the melting zone. In accordance with the nature of the melting, the use of variable-length fins shortens the melting time by 14.9% compared to the equal-length fin arrangement. Similarly, variable-length fins reduce the average temperature of the latent heat thermal energy storage (LHTES) by around 10 °C compared to the equal-length fin arrangement. The use of variable length fin arrangements ensures a more homogeneous melting process within the LHTES. The fin arrangement evenly distributed to the entire heating source is more effective at low heating rates. In contrast, fin arrangements evenly distributed over the lower half of the heating source are more efficient at high heating rates.