Enhancing solar energy efficiency with hybrid CSP systems: Design and analysis of a parabolic dish collector integrated with thermal energy storage

Solar energy is a sustainable and environmentally benign renewable energy source, offering clean energy without emitting greenhouse gases. Solar energy possesses the potential to satisfy global energy, heating, and cooling requirements. Concentrated Solar Power (CSP) technologies find their applications at large scale as compared to photovoltaic system. In this study, a parabolic trough collector integrated with a stratified storage tank is dynamically simulated in TRNSYS® software to test different thermal energy storage materials at varying loads to evaluate efficiency and solar fraction. The heat capacity (Cp) and density (ρ) of materials were varied ranging from 950 to 1000 kg/m³ and 4.10–4.19 kJ/kg.K for water, 960 to 645 kg/m³ and 1.85–2.0 kJ/kg.K for thermal oil, 1700–2100 kg/m³ and 1.4–1.56 kJ/kg.K for molten salt, respectively. A 5.5 m² parabolic dish collector prototype featuring a mirror and thermally insulated storage tank connected in a closed loop was designed and fabricated to analyse the thermal energy storage and transfer. Results showed that indirect thermal storage proves more compatible as it allows for the interchangeable use of heat transfer fluids like glycol-water mixtures and thermal oil, reducing rusting since the fluid only transfers heat to the storage tank without directly affecting the system. Key findings include a maximum solar fraction of 75–80 % during February and September, and system efficiency ranging between 50 and 55 % under varying load conditions.