Experimental analysis and advanced 3D computational fluid dynamics of a novel, energy-efficient, and sustainable solar thermal system

Hot water is essential for both domestic and industrial applications, but reliance on fossil fuels for water heating depletes finite resources and contributes to environmental and health concerns. Solar thermal systems provide a sustainable alternative by harnessing solar energy for heating. However, optimizing the efficiency of these systems requires design improvements, which can be costly and time-consuming through experimental approaches alone. Computational fluid dynamics (CFD) offers a viable and cost-effective alternative for performance evaluation and optimization. This study develops a CFD model of a novel flat-plate solar thermal system using ANSYS FLUENT. The system incorporates lenses and a back-box to enhance solar energy capture and thermal efficiency. The Solar Ray Tracing approach is applied to improve model accuracy and computational efficiency. Additionally, an experimental prototype is built, and its performance is measured to validate the CFD model. Analytical calculations further support the validation process. Comparisons between CFD simulations, analytical results, and experimental data indicate a maximum error within 5%, confirming model accuracy. The exit temperature profiles from simulations align well with experimental observations. This validated CFD model serves as an effective tool for optimizing solar thermal systems, offering a cost-efficient alternative to extensive experimental testing. • Experiments validated CFD model with a maximum error under 5%. • CFD model developed using ANSYS FLUENT with Solar Ray Tracing. • Convex lenses and a cast-iron back-box are used to enhance heat absorption. • Solar Ray Tracing method improves accuracy and computational efficiency. • CFD model enables cost-effective performance analysis and optimization.