This work presents a laboratory scale 50kWhth prototype of an innovative radial flow packed bed thermal energy storage. The proposed storage has an inward radial heat transfer fluid flow during charge and a reverted fluid flow, by means of a valve arrangement, during discharge. The storage unit is equipped with differential pressure gauges, mass flow controller and 50?K-thermocouples to accurately measure the thermodynamic behavior of the unit. In order to assess the performance of the proposed thermal energy storage design two specific indicators have been introduced and defined, namely: the temperature uniformity, and the hydrodynamic uniformity. The results of preliminary CFD studies show a maximum temperature deviation of 20°C along the storage axial direction and uniformity indexes higher than 90%.