Sodium dodecyl-benzene sulfonate added paraffin wax with graphene nanoplatelet for photovoltaic panel cooling application

Abstract

Photovoltaic (PV) panels are prone to overheating, ultimately decreasing PV efficiency. One of the solutions to prevent overheating of PV panels is by integrating nano-enhanced phase change material (NPCMs) at the back of the PV panel. Yet, it causes agglomeration, which degrades its thermophysical properties and becomes less effective in reducing the PV temperature. This leads to the addition of surfactants to NPCMs to reduce agglomeration. However, to date, no comparison studies reported how the addition of surfactant in NPCMs improves agglomeration and its thermophysical properties. Furthermore, the performance of this surfactant added NPCMs (SNPCMs) is still not fully explored when placed under field-testing conditions. Thus, this study aims to first evaluate the role of surfactants experimentally on reducing agglomeration and improving the thermophysical properties of NPCMs, followed by a comparison study and evaluation of the SNPCMs' temperature performance as a PV panel coolant under field testing conditions, and lastly, to evaluate the PV electrical performances when integrated with SNPCMs through simulation. The study was conducted in a few stages. The first stage of this study deals with the synthesis of NPCMs and SNPCMs at different nanoparticle weight percentages, followed by the addition of surfactants to the samples. Thermophysical properties, including charging/discharging rate, melting/solidifying temperature, latent heat, specific heat capacity, thermal conductivity, heat transfer rate, total heat stored, and morphological analysis were investigated for all the samples. The second stage of this study investigated the PV temperature reduction when samples were attached to the back of the PV panel. Solar irradiance, ambient temperature, and PV temperature for one sunny day were chosen for the analysis. Assessment of this material's potential electrical performance enhancement when applied to the PV panel was the focus of the final part of this study. Graphene nanoplatelet (GNP) with three different percentages (1wt%, 3wt%, and 5wt%) was used as nanoparticles of interest and added to paraffin wax (PW) to create NPCMs. Sodium dodecylbenzene sulfonate (SDBS) was used as a surfactant. The morphological study revealed that agglomeration and sedimentation were eliminated from the NPCMs when SDBS surfactant was added and led to the thermophysical improvement shown by sample PGS5 (PW/5wt% GNP with SDBS) which showed; (a) 56.3% improvement in charging and discharging rate, (b) 43.2% improvement in latent heat, (c) 69.5% improvement in specific heat capacity, (d) 73.45% enhancement of heat transfer rate, (e) can store the most heat with 64.13% improvement, and (f) relative enhancement by a factor of 25.94 in thermal conductivity. The on-site evaluation showed temperature reduction as high as 44.2% was recorded when sample PGS5 was applied to the back of the PV panel. With PV operating at a lower temperature, the simulation results show that PV produces higher output power with an increase of maximum output power by 16.92% and a 7.37% improvement in efficiency. These results revealed that SDBS surfactant plays a vital role in reducing the agglomeration by enhancing the adsorption forces between PW and GNP, leading to improved thermophysical properties of NPCMs, thus acting as superior material PV coolant, which can ensure a more reliable and efficient PV performance.