Clathrate hydrates as thermal energy storage for buildings: benefits and challenges

Developments in science of materials and increasing energy costs are at the origin of the great progress in the field of PCM (phase change materials), thermoregulating materials that optimize the daily fluctuations of temperature. A phase change material is able to accumulate a large amount of heat at a constant temperature, at which physical phase change from liquid to solid takes place. PCMs allow to optimize temperature daily fluctuations, resulting in buildings in thermal performance improvement and therefore in energy savings. The present work is aimed at studying the application of Gas Hydrates as PCM. GH are solid compounds that are formed in particular conditions of temperature and pressure, characterized by a regular structure of water molecules in the cavity of which are trapped molecules of gases or organic compounds. All thermodynamic, chemical and economical requirements making PCMs suitable in building application will be assessed and analyzed. In particular, GH phase change temperature and enthalpy are discussed, since phase-change materials have to be optimal to store and release heat at all. Furthermore gas hydrates molecules performance are evaluated. GH application as PCM is underlined, since the improvement of these materials can be a further important opportunity to heat storage and energy and money saving in building. Finally the limits and the possible further development of GH application as PCM in buildings are discussed, since spread application in building can be an interesting outcome both for this technology, and for the development of Science of Materials.