Investigation of packed bed pouches filled with phase change material for air heating

Latent heat thermal energy storage system has high energy storage density and uses phase change materials; thus, it is an essential device for utilizing intermittent renewable energy, such as solar heat. Recently, research on demand management of building heating energy using latent heat thermal energy storage has gained increasing attention. Latent heat thermal energy storage-based building thermal energy management is advantageous for space heating that directly heats indoor air; in particular, improving the heat transfer rate of phase change materials and reducing the total melting time to maximize the system performance are attracting attention. In this study, a packed bed pouch system for air heating was developed, and its charging and discharging performance was analyzed using experimental and numerical methods. The packed bed pouches were filled with noctadecane as a phase change material, and the thermal performance was investigated through a parametric study. During the experiment, the temperature and melting fraction in the single pouch were measured over time, and the reliability of the numerical results was validated. Consequently, a temperature increases of 22 & DEG;C was measured during 10 h of charging with an air flow rate of 0.009 kg/s. The amount of thermal energy and rate of heat transfer for the charged and state were 2.1 MJ and 55 W, and those for the uncharged state were 0.91 MJ and 42 W, respectively. In addition, in the case of the unaligned layout, the Nusselt number increased by 21.8% and phase change material melting duration was 15% shorter, as compared with the case of aligned layout. Finally, indoor heating using the heating chamber was performed. In the discharge experiment, air at 30 & DEG;C was supplied to the heating chamber at a flow rate of 0.009 kg/s; consequently, the temperature of the heating chamber increased by 15 & DEG;C, from 5 to 20 & DEG;C, and then remained constant for 30 min. In conclusion, the performance and utility of the air-type packed bed pouch system developed in this study were confirmed.

Automated summary

Latent heat thermal energy storage system is essential for utilizing intermittent renewable energy, and research on its application in building heating energy management is gaining attention. A packed bed pouch system for air heating was developed in this study, and its charging and discharging performance was analyzed using experimental and numerical methods.