A new annex on "Phase Change Materials and Chemical Reactions for Thermal Energy Storage" was approved during the 43rd meeting of the Executive Committee of the Implementing Agreement on Energy Conservation through Energy Storage (ECES) within the International Energy Agency. The Department of Chemical Engineering and Technology at the Royal Institute of Technology in Stockholm will act as Operating Agent for Annex 10. Participants in the annex are Bulgaria, Canada, Finland, Germany, Japan, Poland, Sweden and Turkey. Further members could be Australia, China, the Netherlands, United Kingdom, and USA. The First Workshop of the Annex was held in Adana, Turkey on the 16th and 17th of April 1998. Participants were from both universities and industry.The Second Workshop will be held in November, possibly in Bulgaria. A state-of-the-art report will be produced by the Operating Agent in cooperation with all participating countries. A preliminary version of the state-of-the-art report will be presented at the Second Workshop as well as case studies carried out by the different countries.

In order to utilize alternative energy sources, which are available at times when energy is not needed, energy storage is required. Another reason for energy storage is to reduce the size of energy production equipment. The storage enables a continues energy production at a constant level. When the energy demand is smaller than the rate of production energy is stored whereas when the demand is larger than the rate of production, energy will be withdrawn from the storage. If you want to know how TES works, follow this link.

Thermal energy storage systems are lately gaining an increasing interest. This can partly be attributed to the growing interest in:

• cogeneration of electricity and heat.
• solar energy.
• primary energy savings by use of waste heat.

Although the technology of thermal energy storage is capable of meeting constraints on environmental protection and energy savings it is currently a rather unattractive option. It seems that the transfer of theoretical and experimental knowledge from research centres into full scale applications (i.e. demonstration plants) has been unsuccessful.

Objectives of Annex 10

The objectives of Annex 10 are in general to solve technical and market problems for a better market opportunity for thermal energy storage systems utilizing PCM or chemical reactions and to broaden the knowledgebase and disseminate information. The field of application for the technology will be in the building, the agricultural and industrial sector. The scope of the work undertaken in this annex include thermal energy storage by solid-solid, solid-liquid, liquid -vapor and solid-vapor phase transfer, for instance melting/solidification, crystallization/solubilization, vaporization/liquifaction and solid sorption processes as well as by chemical reactions. Research will be carried out to find solutions to the difficulties in using PCMs or chemical reactions for thermal energy storage. These difficulties includes:

• to find a suitable material for the required temperature range.
• mass and heat transfer limitations.
• reversibility of the phase change.
• system integration.

In particular research into system analysis will be carried out in order to recognize market barriers for implementing the technology in residential, commercial, industrial and agricultural sectors. The action will be executed in close co-operation with manufacturers, utilities, users, governmental representatives and organizations involved in the dissemination of energy technologies. The Annex 10 will result in accomplished/initiated case studies and demonstration projects related to potential fields of application. Furthermore it should give general recommendations for the energy industry and more application oriented R & D activities with increased participation of industry, manufacturers etc.

Source: Chemical Engineering and Technology, Royal Institute of Technology

Last updated: 2000-06-15  webmaster@ket.kth.se