Benjamin Lucke's Successful Defense of His Dissertation in Energy Process Engineering

As part of his dissertation, Dr. Lucke developed and extensively investigated a thermochemical storage material based on calcium hydroxide, Ca(OH)₂.

The goal was to develop a storage material that not only exhibits high energy storage density but is also mechanically stable and suitable for repeated use in technical storage systems. To this end, the manufacturing process for the storage granules was first systematically optimized. Particular focus was placed on stabilizing the granules as well as ensuring the most efficient transport of material and heat. The coating process developed as part of this effort enables the production of a stabilizing, yet flexible and semipermeable, aluminum oxide shell around the individual granules.

Following optimization on a laboratory scale, the manufacturing process was scaled up to a pilot plant scale. In a reactor setup developed in-house, the storage material was then repeatedly loaded and unloaded under conditions simulating real-world use. The investigations showed that the developed granules can be used stably over multiple cycles and are therefore fundamentally suitable for practical use in thermochemical heat storage systems. In a demonstration test, a heating circuit was also successfully operated using the developed storage material. The efficiency achieved in this test still has room for improvement but offers starting points for further optimization, particularly through an adapted reactor design.

Another focus of the work was on the question of how the storage material can be reused after the end of its service life. A recycling process was developed for this purpose. It was found that adding small amounts of the recycled TCES material to a cement mixture can even slightly increase its strength without adversely affecting the cement’s fundamental properties.

The dissertation thus examines the entire life cycle of the storage material, from the selection of raw materials through material development and manufacturing to technical application and subsequent recycling. In doing so, Dr. Lucke has made an important contribution to the development of sustainable thermochemical energy storage and has demonstrated the potential of calcium hydroxide as a cost-effective and globally available storage material.

Congratulations on this innovative and outstanding scientific achievement. We wish Dr. Lucke much success in his future career and hope he continues to generate numerous innovative ideas.