Energy storage by PCM for building applications

This chapter presents a detailed overview on the use of phase change materials (PCMs) for being used in various building applications particularly from the viewpoint of reducing fossil fuel-based energy consumption in the buildings for HVAC (heating, ventilation, and air conditioning) and other applications. Buildings form the major portion (30%) of the total energy consumption worldwide; thus there exists an ample opportunity to exploit the latent heat of PCMs for thermal regulation in buildings. Also the growing concerns over environmental issues which are directly linked with the emission of greenhouse gases through building air conditioners have made us to rethink and critically examine the alternate and sustainable techniques as per the building's requirement. Use of phase change materials particularly in the last decade has gained a significant attention from all round the globe not only from research point of view, but its use now has also become commercially viable for various thermal energy storage-based building applications. The chapter follows a comprehensive approach, i.e., starting from the introductory concepts like sensible and latent heat, classification of phase change materials, and selection criteria for PCMs to the most advance techniques like microencapsulation adapted for various building applications which have been discussed in sufficient detail. The large amount of stored latent heat and the peculiar isothermal nature of heat addition and rejection during phase change have made phase change materials (PCMs) an ideal candidate for storage-based thermal regulation in buildings. Special attention has been given to PCM's use in building applications categorized as (i) water and air heating applications, (ii) HVAC/solar absorption systems for building, (iii) building integrated systems (walls, ceilings, and floors), and (iv) other useful techniques like Trombe wall, PCM shutters, and PCM concrete.