Technology Outline (Process Description)

Solar energy has a huge potential to satisfy current and future energy demands. However, the challenge of its intermittent nature has to be addressed. Integration of solar thermal systems with latent heat storage (LHS) systems is an effective technique to address this challenge. With the advantages like high energy storage density and a near isothermal operation, an LHS system is developed for high-temperature applications. Sodium nitrate with a melting temperature of 305∼ and phase change enthalpy of 175 kJ/kg is used as PCM. It undergoes phase change during the energy storage/retrieval process. PCM is encapsulated in the cylindrical capsules to improve the heat transfer characteristics. The LHS system consists of seven such capsules placed inside a cylindrical shell. Experiments were conducted to investigate its charging and discharging performances in the temperature range of 270-330∼. The charging and discharging times were 147.5 min and 121.5 min, respectively, which are most suitable for the real-time thermal energy storage system. LHS system with approximately 14 kg of PCM mass, stored/discharged a total heat of 3.97/ 3.94 MJ in the given temperature range.