Evaluating the role of sodium dodecylbenzene sulfonate as surfactant towards enhancing thermophysical properties of paraffin/graphene nanoplatelet phase change material: synthesis and characterization in PV cooling perspective

Abstract

Nanoparticles addition in the phase change material (PCMs) has been proved to improve its thermophysical properties. However, it also has been reported to cause agglomeration, which will counteract the thermophysical enhancement. The addition of surfactant to this matrix is believed to reduce the agglomeration. However, no comparison studies reported how the addition of surfactant in nano-enhanced phase-change material (NPCMs) improves its thermophysical properties and has assessed its performance in enhancing the temperature-reduction characteristics of PV panels under field-testing conditions. Hence, this work aims to experimentally evaluate the impact of adding surfactants to the NPCMs matrix to improve its morphological and thermophysical properties and evaluate its performance in outdoor conditions. Graphene nanoplatelet (GNP) with 1, 3, and 5 wt% (PG1, PG3, and PG5) was added to the paraffin wax (PW), followed by the addition of sodium dodecylbenzene sulfonate (SDBS) as the surfactant (PGS1, PGS3, and PGS5). Thermophysical properties such as latent heat, specific heat capacity, thermal conductivity, and total heat stored were investigated. The best improvement was shown by sample PGS5 (PW/5 wt% GNP with SDBS) with the performance of; (a) 43.2% improvement in latent heat, (b) 69.5% improvement in specific heat capacity, (c) 73.45% enhancement of heat transfer rate, (d) total heat stored with 64.13% improvement, and (e) relative enhancement by a factor of 25.94 in thermal conductivity. On-site evaluation on PV module also showed the reduction of temperature as high as 44.2%. All this proving the importance of SDBS to improve the thermophysical properties and suitability as a PV module coolant.