Bahareh Abdoos, - Caspian Faculty of Engineering, College of Engineering, University of Tehran
Ali Fazeli - Caspian Faculty of Engineering, College of Engineering, University of Tehran

By increasing the population and level of human welfare, the energy demand is growing rapidly. Energy saving in buildings can be obtained using thermal energy saving (TES) technologies. Phase change materials (PCMs) store energy and release it periodically using latent heat of melting. Recent advances and application of PCMs in buildings are reviewed in this article and advantages/disadvantages of each PCM type are compared. In recent articles, some nano-particles were added to PCMs in order to improve the properties of PCMs. Therefore, recent advances of nano-PCMs are summarized in different building applications in addition to general PCMs. Recent trends and case studies in finding composite material, eutectic mixtures and using nano shape materials for improving thermo-physical properties of PCMs were reviewed briefly. The concept of macro and micro encapsulation of PCMs were discussed that is applicable in reducing the leakage of PCMs. The studies show that Nano-PCMs are new materials that are used small amount of nano-shaped materials for increasing thermal conductivity and hence heat transfer coefficients. In some cases, nano materials can increase the latent heats or increase biodegradability of the PCMs. The researches in this field are growing rapidly for green buildings to reduce the energy cost at the lowest increase in capital cost. Finding new materials and composites can help in a way that energy saving will be winner of this trade-off between energy and capital cost of a building or building facilities.

Energy Saving, Phase Change Material (PCM), Nano-PCM, Building,Thermal Energy Storage (TES).