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M. Jakobi, P. Hofmann, B. Geringer:
"Restwärmenutzung durch intelligente Speicher- und Verteilungssysteme";
Talk: FVV Herbsttagung, Dortmund; 2012-09-27 - 2012-09-28; in: "Informationstagung Motoren Herbsttagung 2012", FVV, Heft R560 Dortmund (2012), 89 - 112.

The goal of this project is the storage of waste heat of internal combustion engines and utilization at the next cold start to minimize the warm-up period to reduce the fuel consumption
of cars. As a benchmark for the comparison of the systems serves the coolant exchange storage introduced at the literature study. A new and innovative possibility to store heat should help to compensate the various problems (low storage density, thermal isolation of
storage medium, losses at long parking duration as well as the difficult placing in the vehicle)and to improve different important criteria. The literature study returns that reversible chemical
reactions, which proceed under supply or release of thermal energy, are generally able to store heat. Besides the loss-free storage over long periods and the higher energy density in common, this technology can be used to climate (air-condition) the car additionally.
An especially developed heat storage test stand was build during the project and furthermore intensive investigations with different chemical reactions were carried out. Thereby reaction characteristics and heat dissipation were analysed. An important criterion is the course of the reactions at low temperatures down to -15 °C. In succession a prototype storage system was developed, which admits investigations close to automobile applications. Therewith various measurements with different reaction parameters were carried out as well as different steps for process optimisation.
Researching results demonstrates that the usage of waste heat by chemical reactions based on salt hydrates is generally possible at automotive applications. Additionally it seems to be an interesting area for further investigations at automobile developments to increase the overall efficiency.