In this laboratory study, an attempt has been made to explore the details of the effect of an ultrasonic field on the melting behavior of pure phase change materials (PCMs) and nano-enhanced PCMs using images recorded with digital and thermal cameras. A 50/50 mixture of beeswax and coconut oil was employed as the pure PCM and the copper oxide nanoparticles were used to improve the thermal aspects of the pure PCM. Three different mass concentrations i.e., (1 %, 2 %, and 4 %) were considered for nanoparticles. The required ultrasonic field was generated using two stainless steel 27 kHz 40 W piezoelectric transducers. It was revealed that the application of ultrasonic field to the pure PCM and nano-enhanced PCM containing 1 %, 2 %, and 4 % of nanoparticles reduces their complete melting time by 58.33 %, 60.00 %, 61.39 % and 64.44 %, respectively. The images taken with the digital and thermal cameras confirmed that agitation oscillating fluid motion and cavitation are two mechanisms that definitely contribute to the improvement of PCM melting characteristics in the presence of ultrasonic field.
