Due to the energy revolution and the need for sustainable energy sources, energy storage systems are getting more significant. Therefore an existing fixed bed regenerator from the Institute for Energy Systems and Thermodynamics (IET) has been adapted and improved. With the regenerator energy unit it is possible to investigate the charging and discharging behaviour of thermal heat energy of different fixed bed storage concepts. For that purpose cold ambient air is sucked in by a blower machine and blown through an air heater. The heat provided from the heater is blown through a fixed bed, stored in a container. There the heat from the hot air, is transferred to the storage medium which in this case is a swell of broken rocks. After the hot air has been blown through the fixed bed, the yet colder air is blown into the environment through an exhaust pipe. To discharge the storage again, cold air is sucked in with the blower-machine and transferred through the fixed bed from the opposite direction through the storage container. After the cold air adopted the heat from the fixed bed, the warm air can be used for further industrial processes. In the case of this testing facility the air is blown into the environment again. The main improvements on this testing facility, is made on the tubing and the machine control. The tubing has been adapted so that it is also possible to discharge the storage with pre-heated air from the air heater. Furthermore a bypass tube has been installed which bypasses the container. With this improvement the measurements should not be negatively affected in stages where the machine is preheating or cooling down. The unit is now controlled by a modern SPS controlling system from B&R, to achieve more precise results and make the testing facility safer. Additionally an extension of the storage container has been developed in this thesis. The extension makes it possible to use a combination of sensible and latent storage mediums. Beside the calculations for the storage extension, construction plans can be found in this thesis.