Studies on Energy Storage Capacity of a Spherical Encapsulated PCM Using Eutectic Salt as Phase Change Material

The need for higher productivity to match the growing competition has forced employers to look for better Indoor Work Environments. Since most of the buildings are being air conditioned, the Heating Ventilating and Air Conditioning (HVAC) systems account for nearly 40% of total building energy consumption. To reduce this energy consumption Thermal energy storage systems (TES) were developed. The Latent heat thermal energy storage (LHTES) systems using water/ice are commonly used for peak shifts in electrical demand. To maintain a temperature below 0C, the water/ice storage system is not suitable, but for a HVAC application the chiller requires a temperature below 0C. In TES systems, phase change materials (PCMs) have attracted a great interest as thermal storage materials because the thermal energy is stored in them with high density and it is also possible to maintain below 0C. This research uses Sodium nitrate along with nucleating agent (borax), freeze point depressant (ethylene glycol) and thickening agent (propylene) as a eutectic mixture in PCM. The percentage of composition of these selected phase change materials are Sodium nitrate 33%, ethylene glycol 27%, borax 22% and propylene 18 %. The numerical studies are conducted to determine the maximum storage capacity of the eutectic mixture and also the influence of the nodule size on TES.