Experimental Comparison of Packed-Bed Sensible TES Charging with the Schumann Model: Trends, Deviations, and Proposed Corrections

The Schumann model has long governed packed-bed sensible thermal energy storage design, but its simplicity leaves some phenomena unexplained. This study aims to compare experimentally measured charging dynamics against Schumann model predictions. The experimental setup consists of a basalt crushed rock packed bed (0.8 m height, 500 mm diameter) with air as thermal fluid at a flow rate of 5.7 L/s, heated at 200°C with a 12kW heater. The custom-built TES includes 11 longitudinal and 8 axial thermocouples to record temperature profiles and thermocline development. Experiments are currently underway, with interesting phenomena clearly visible on the temperature profiles. Expected outcomes include: (1) quantification of model-experiment agreement, (2) quantification of the main assumptions on the model (plug flow, Biot number…), (3) proposed corrections if systematic deviations are confirmed. These results will provide inform improved design correlations for packed-bed TES systems.