Bio-phase change materials based on stearin of sheep tail-fats loaded with nanoparticles: Melting performance analysis in rectangular cavity as a sustainable building envelopes

Abstract

Applying bio-based phase change materials (BPCM) using environmentally acceptable resources as an alternative to petroleum-based phase change materials (PCM) in buildings presents an opportunity to reduce greenhouse gas emissions to almost zero, besides decreasing energy consumption in achieving thermal comfort in a building. Thus, this research aims to investigate numerically and experimentally the melting behavior of stearin of sheep tail-fats (SSTF) as the BPCM in a rectangular cavity acting as the sustainable building envelope, as well as the effects of carbon nanotube (CNT) additives on the SSTF melting behaviors. The results suggest that the convection heat transfer mechanism plays an important role in the heat transfer within the SSTF envelope due to its poor thermal conductivity. This leads to the non-uniform melting progress inside the container. The inclusion of 0.03% CNT in the SSTF leads to a slight increase in the thermal conductivity of the SSTF composite because of the high number of the CNTs’ tangled tube bundles inside the SSTF. When compared to the SSTF without the CNT, it quickens the melting process and the melted SSTF’s velocity (the convection strength) by about 11% and 8.7%, respectively. Not only that, it also enhances the heat transfer and the thermal storage rate by about 13.7% and 7.5% respectively. Therefore, this research concludes that the SSTF with CNT as the additive offers a potential to be the effective passive TES envelopes for the building walls that leads to a potential application in the low-carbon thermal comfort control of buildings.