Compact Thermal Energy Storage:
Material Development and System Integration

Task Information Duration January 2009 -- December 2012 Operating Agents SHC Wim van Helden ECN Energy Research Centre of the Netherlands vanhelden@ecn.nl ECES Andreas Hauer ZAE Bavarian Center for Applied Energy Research Germany hauer@muc.zae-bayern.de Task News The Task was approved at the June 2008 IEA SHC Executive Committee Meeting in Graz, Austria

Overview

Task 42 is a joint Task with the IEA Energy Conservation through Energy Storage (ECES) Programme Task 24.

Thermal energy storage is an important technology for renewable energy systems and energy efficiency. By improving the effectiveness of thermal storage, the effectiveness of all renewable energy technologies that supply heat can be improved.

Particularly for solar thermal systems, thermal energy storage is essential. To reach high solar fractions, it is necessary to store heat (or cold) efficiently for longer periods of time. Until now, no cost-effective compact storage technologies are available to do this. For high solar fraction systems, hot water stores are expensive and require very large volumes of space. Alternative storage technologies, such as phase change materials (PCMs) and thermochemical materials (TCMs) are available on a laboratory scale. However, more research and development is needed before these technologies can be developed into commercial solutions.

In several IEA Annexes , it was concluded that materials are the main bottleneck for finding effective solutions for compact thermal energy storage, and that there is a need for new storage materials with a higher specific energy storage density and lower material cost.
Around the world, several groups are working on either thermal energy storage materials or applications. However, these activities are not sufficiently linked. The current activities are either limited to specific applications, or to specific materials. What is needed, and what can be provided by this task, is a way to bring the ongoing work on materials and applications together.

Until now, two expert meetings were held to help shape this task: a first expert meeting in October 2007 in Zürich, Switzerland, followed by a Task Definition Meeting in April 2008 in Petten, the Netherlands. In addition, a proposal for the Task was presented to both the ECES and SHC ExCos in November and December 2007, respectively. Finally, a separate meeting was held in Düsseldorf, Germany in March 2008 between the two proposed Operating Agents and the Dutch and German ExCo members, to discuss the possibility and desirability of organising the Task as a Joint Task. This document is the result of these five meetings.