Chemical energy storage using reversible solid/gas-reactions (CWS) - results of the research project

Within a four year joint research project the technical feasibility of thermo-chemical heat storage for solar thermal applications and the achievable advantages compared to conventional storage technologies have been investigated. The project, directed to applied research, was divided into a high temperature (> 300 degrees C) and a low temperature part (< 100 degrees C). In the low temperature part the main focus was on the development of a compact seasonal heat store for single or multifamily houses. Concerning high temperature applications thermo-chemical energy stores show high potential for improving energy efficiency of power plants and for recovery of process heat. The investigations have been carried out by a close cooperation of the Institute of Thermodynamics and Thermal Engineering (ITW) of the University of Stuttgart, specialised for solar thermal heating in the building sector and the Institute of Technical Thermodynamics (ITT) of the German Aerospace Center (DLR) as a specialist on solar thermal power plants. The project started in 2008 and runs until end of June 2012. This paper will focus on the low temperature part of the project, discuss important experiences and recent experimental results of the project and will report the very latest developments. Moreover the paper will summarise the important improvements achieved for temperature thermochemical heat storage. Finally recommendations for future activities will be given. (C) 2012 The Authors. Published by Elsevier Ltd.