Influence of solar heat sources on packed bed TES performances

The influence of solar constraints is investigated on the Eco-Stock (R), a commercial packed bed developed by the company Eco-Tech Ceram (1.9 MWhth at 525 degrees C). The first test takes into account the simulated solar power variation along the day. Power variation has a minor impact on the packed bed performance, with a 3% decrease on the yield at 0.8 of cutoff temperature. Numerical results match the experiment, proving the model to handle properly power variation. The second test takes into account intermittencies, due to potential clouds. The stand-by phases had a major impact, reducing the yield by 13% at 0.8 of cutoff temperature, due to heat losses and both axial and radial stratification.