Abstract
Solar energy has the potential to be used for energy applications. However, its thermal performance can be affected by weather conditions, changes in solar radiation, and cloudy days. This study aims to resolve the mentioned disagreement and improve the solar thermal performance of flat plate solar collectors (FPC) that use beeswax phase change material and a hybrid nanofluid made up of (50:50) zinc oxide (ZnO) and magnesium oxide (MgO) at a concentration of 1-3 volume, operated at 2 litres per minute (LPM). The different volume concentrations include hybrid nanofluid (ZnO/MgO) at 1 vol%, PCM mixed with hybrid nanofluid (ZnO/MgO) at 2 vol%, and PCM combined with hybrid nanofluid (ZnO/MgO) at 3 vol%. The hybrid nanofluid that results has an improved heat transfer rate, reduced heat loss, greater latent heat storage, and better thermal and exergy efficiency than water. The hybrid nanofluid (ZnO/MgO) at a concentration of 3 vol% has the highest thermal conductivity, reaching around 0.93 W/mK. It also has an outlet temperature of 91.5°C, a heat transfer rate of approximately 398.4 W, and a latent heat storage capacity of about 389.1 KJ/kg. Additionally, the typical thermal efficiency is around 68.6%, while the average exergy efficiency is about 30.1%.
