Experimental investigation and simulation of a helical coil heat exchanger with hematite thermal reservoir

This paper introduces an innovative helical coil heat exchanger using Hematite as a heat storage material, enhancing retention and thermal management. Parabolic trough collectors deliver heat to the heat exchanger's shell side using Therminol VP-1 with Al₂O₃ nanoparticles, while another collector supplies vapor to the helical coil connected to a turbine. A concentric cylinder serves as a rechargeable heat reservoir. The study presents a control-oriented modeling methodology for a practical TES tank with a helical immersed heat exchanger. Temperature dynamics of the heat transfer fluid within the tank are discretely modeled for computational efficiency in real-time simulations. A simulated case with model-based feedback control demonstrates the efficacy of this approach, validated by comparing simulation results with experimental data. Results show a close correlation between the surface temperature of the heat storage tank and the helical coil temperature, affirming model accuracy and reliability. The system achieves an efficiency of 37%. A case study involving a 1 Kw steam-operated power plant (150–200°C, 7–10 bar, 50 kg/h) illustrates the practical application and benefits of the methodology in achieving intelligent and efficient TES system operation.