Performance enhancement of nanofluid-based photovoltaic/thermal system with a novel finned multi-block container of phase change material in the summer season of northern India

This study describes the outdoor experiments conducted on a photovoltaic/thermal (PV/T) system during the summer months of May and June in the year 2023, in northern India. The main goal of this paper is to reduce the temperature of a photovoltaic (PV) module for effective thermal regulation by implementing a hybrid cooling strategy in a PV/T system. This is achieved by integrating two techniques: multi -walled carbon nanotubes (MWCNT)-water nanofluid as the working fluid for active cooling and paraffin wax as the phase change material (PCM) for passive cooling. Therefore, the present study aims to design, fabricate, and test an innovative thermal collector with a multi -block finned absorber plate positioned beneath the PV module to promote uniform heat transfer distribution and mitigate temperature stratification within each PCM block. The proposed PV/T-PCM system's performance is assessed from energetic, exergetic, economic, and environmental standpoints compared to the PV/T system and conventional PV module. The present study also examines the impact of different concentrations (0.1 - 0.2 %) of MWCNT and volumetric flow rates (0.5 - 1.5 l/min) of both water and nanofluids as heat transfer fluids. It is shown that a desirable flow rate of 1.5 l/min yields the most favorable outcomes. The PV/T-PCM (0.2 %) system has been found to exhibit the highest levels of energetic and exergetic electrical and thermal efficiencies, with reported values of 13.25 %, 65 %, 12.81 %, and 1.66 %, respectively. The economic assessment demonstrates that the proposed PV/T-PCM system, integrating water and nanofluid, results in cost savings of 17.41 % and 19.63 % compared to a traditional uncooled PV system. In the context of environmental sustainability, the highest net CO 2 mitigation is estimated to be 18.01 tons for the nanofluid-based PV/T-PCM system. Thus, the results confirm that the proposed PV/T-PCM (0.2 %) system, incorporating a hybrid cooling technique, achieves optimal performance.