ABSTRACT The development of sustainable, cost‐effective and efficient phase change materials (PCMs) is essential for advancements in thermal energy storage technologies. In this study, a hybrid organic PCM is developed by blending petroleum‐based paraffin wax and bio‐based beeswax in equal proportions. Further, the effect of reinforcement of graphene nanoparticle at different concentrations (0.0 to 1.0 wt.%) on PCM properties is investigated. The hybrid and hybrid nano‐PCMs are characterized for heat storage capacity, phase transition behavior, thermal conductivity, thermal stability, functional groups, and rheological behavior. The heat storage capacity is enhanced by a maximum of 14.5% at a low graphene concentration (0.2 wt.%), while higher concentrations resulted in its reduction. In contrast, thermal conductivity increased consistently with graphene loading, reaching a maximum enhancement of 195.2% at 1.0 wt.%. An optimal graphene concentration of 0.2 wt.% is identified for a balanced improvement in heat storage capacity and thermal conductivity. Thermal stability and viscosity are found increasing with graphene concentration, but its effect on viscosity is found minimal at low shear rates. The developed PCM composites exhibit high thermal energy storage capacity along with excellent chemical and thermal stability, even after 200 thermal cycles. Also, the PCMs are experimentally evaluated under no‐load and load conditions in a solar dryer. An extension of drying duration until 9:00 and 10:00 p.m. is achieved using hybrid and hybrid nano‐PCM, respectively. Also, hybrid nano‐PCM exhibited superior performance by maintaining higher dryer temperature. The developed PCMs resulted in lower payback periods (2.53 and 2.27 years), higher benefit–cost ratios (0.395 and 0.44) and higher carbon‐benefit ratios (13.06 and 14.15), which makes them suitable for low temperature solar drying applications.
Kabeer et al. (Wed,) studied this question.