Development and thermodynamic characterization of new materials for thermal storage by latent heat

Abstract

The need for efficient thermal energy storage materials has escalated with the adoption of sustainable energy systems. Paraffin wax is one of the most widely used phase change materials because of its high latent heat storage capacity, stability, and cost-effectiveness. However, its low thermal conductivity of approximately 0.2 W/m•K and possibility of phase separation hinder its thermal efficiency, despite improvements by nanofilers and carbon additives. A new approach for enhancement, which can be sustained in an efficient manner using Algerian slack wax, an underutilized petroleum derivative with immense potential, shall be proposed in this research work. PCMs with a combination of 6, 10, 15, and 20 wt% slack wax were studied by using a T-history test. The performance analysis reveals a collective advancement in different properties of PCMs, which is not a common phenomenon in PCM enhancement studies, where trade-off is considered. The combination with 20% slack wax proved to be most effective with a maximum increase of 35.65% in latent heat capacity from 106.93 kJ/kg to 145.06 kJ/kg, 30.48% in specific heat capacity from 3.51 kJ/kg•K to 4.58 kJ/kg•K, and a 33% boost in solid-phase thermal conductivity from 0.18 W/m•K to 0.24 W/m•K. Moreover, solidification time reduced by 25% from 165 s to 120 s and melting time reduced by 20% from 125 s to 100 s, respectively. The observed modifications in PCMs can be attributed to intermolecular interaction among paraffin and slack wax, which leads to an improper crystallization pattern with good transport properties. Use of an industrious waste in this manner can prove beneficial for cost-effective production of a higher-performance PC McA in an economical manner with sound eco-green concepts in the energy department in Algeria.