The power block is of immense importance to the SOCRATCES technology, its chief role being conversion of liberated thermal energy in to electricity for consumers. While there are numerous different approaches of integrating a suitable thermodynamic cycle to SOCRTACES, for the power block for the SOCRATCES pilot plant, TTZ Bremerhaven, a German research institute, chose a rather novel and unique option of integrating a Stirling engine with the exothermic reactor constructed by CERTH. The power block serves two functions – converting the thermal energy in to electrical power, and preheating the air incoming to the carbonator. The 1 kW Stirling engine was supplied from the Dutch manufacturer Microgen. The integration was carried out using detailed CFD simulation results to enhance heat absorption rate.

Following the completion of the construction of the power block module, it was shipped to the site in Spain where it is now being tested as an integrated part of the SOCRATCES setup. The extensive research and studies that went in to the work have become an asset to TTZ Bremerhaven as it is now able to offer its services to clients with similar needs in engineering integration of Stirling systems. TTZ is also optimistic about participating in further research in similar projects.

One of the most important achievements during TTZ’s participation in to the project was that a novel turbulence model with a unique non-stochastic approach was conceived. While still in its nascent state, it clearly has immense potential in heat transfer technology as an accurate turbulence model has an important correlation with convective heat transfer process. It is especially relevant to the modeling of Stirling engines because the internal turbulent compressible thermodynamics is of great interest to modern researchers, as is the external heat transfer, both involving turbulent phenomena. TTZ Bremerhaven expects to put out a paper in the coming months on the fundamentals of this turbulence model.

TTZ Bremerhaven has partaken in discourse with a prominent Stirling engine manufacturing company in an effort to use its gathered experience for providing commercial research service. It is likely that TTZ Bremerhaven will continue to be involved in the development of Stirling engine integration technology in the future. The acquired expertise in the field of heat integration in solar technologies is also going to be of commercial interest to TTZ in the future. A CFD optimized integration approach has already generated some interest in giving enhanced integration results.