Abstract

This research presents a detailed investigation of the thermal performance of hybrid solar system for space cooling applications, which is experimentally studied by water (baseline), water/hybrid nanofluid (50:50 ratios of graphene: alumina nanoparticle), and water/hybrid nanofluid with 70, 80, and 90 % of sodium sulfate decahydrate (Na2SO4·10H2O – Glauber's salt) with 1 wt% borax nucleation agent is used to enriching the phase change behaviour. The influences of hybrid nanofluid and its combined action with varying percentages of Glauber's salt phase change material (PCM) on the thermal performance, latent heat of fusion, and coefficient of performance (COP) of the cooling system will be studied and compared to baseline results. The significance of hybrid nanofluid and improved percentages of Glauber's salt offered better thermal performance and higher COP performance than water fluid. Moreover, the hybrid solar system functioned with 1 % of hybrid nanofluid and 90 % Glauber's salt/1 % borax provided optimum behaviours like higher thermal conductivity (1.38 W/mK), improved specific heat capacity (5147.9 J/kgK), better latent heat of fusion (187.8 kJ/kg), COP peaks at about 6.2, higher cooling capacity (9.0 kW), and reduced thermal diffusivity (0.163 mm2/s) and thermal cycle stability of (95.8 %), confirming excellent long-term operational reliability. © 2025 Elsevier Ltd