Transfer of laboratory results on closed sorption thermo- chemical energy storage to a large-scale technical system

Abstract

The studies reported here are focused on the development of an efficient, closed thermo-chemical heat storage system in an appropriate scale for the integration into industrial processes as well as heating systems. Such a storage method offers several advantages including the possibility of long-term storage with minimal thermal losses and a high- energy storage density compared to sensible and latent thermal storage principles. This makes it possible for medium- temperature solar collectors and other heat sources of high potential to be applied in industrial processes; which is rarely done nowadays due to the lack of suitable thermal storages. From the results of the tests on a laboratory scale unit with 1.5-liter storage volume, suitable storage materials as well as optimal process conditions such as the temperature and pressure ranges were identified. Applying these attained process conditions, different heat exchanger concepts were developed, tested and optimized in 15-liters storage units. The result was a new heat exchanger configuration that showed a more than 60% higher heat power rate than measured with standard heat exchangers in the bulk. The concept comprises a combination of several measures to increase the storage density by improving the mass and heat flow in the system with minimum loss of storage volume. As the last step, this improved concept was applied in an up-scaled heat storage system with 750-liters storage volume.