Long-term thermophysical behavior of paraffin wax and paraffin wax/polyaniline (PANI) composite phase change materials

Phase change Material (PCM) has immense potential in the field of energy storage due to its latent heat capacity. In this study, accelerated thermal cycling is performed on Paraffin wax (PW) and Paraffin Wax/Polyaniline (PWP-1) composite up to 3000 cycles to evaluate its durability. The latent heat of PW reduced by 6.7% at the end of 3000 cycles, whereas the composite PWP-1 reduced by 9.8% but PWP-1 had higher latent heat values compared to PW. The melting temperature showed an increment with the number of thermal cycles with 11.7% and 23% increment for PW and PWP-1 composite respectively. Thermogravimetric analysis showed very little change in the weight degradation after thermal cycling, but the Fourier Transform Infrared Spectrometry showed a new absorption peak for PW and PWP-1, which may be due to the formation of carbon/char. Visual and microscopic images of the samples are analyzed. From the study it can be concluded that PWP-1 composite has better thermal reliability in terms of latent heat as compared to PW and can be used in the field of solar application like flat plate solar collector, photovoltaic thermal system and low concentrated photovoltaic thermal systems for the production of domestic hot water application.