ISSN Online: 2377-424X
ISBN Print: 978-1-56700-421-2
International Heat Transfer Conference 15
Performance Analysis of the Molten-Salt Thermal Storage System Filled by PCM Capsules with Cascaded Melting Temperatures
Abstract
We present a transient, one-dimensional dispersion-concentric (D-C) model to numerically study the
charging and discharging behaviors of the molten-salt thermal energy storage system filled by PCM capsules
with cascaded phase change temperatures (PCTs). Three different storage systems including the non-cascaded
system, the cascaded system with 3 PCTs and the cascaded system with 5 PCTs are investigated.
Detailed characteristics of heat transfer between molten salt and the packed PCM capsules are revealed, and
various numerical results are examined, including the temperature distributions of molten salt and PCM
capsules, the variations in the molten-salt outlet temperature, the accumulated charging and discharging
ratios, etc. The results show that for cascaded systems, some stored latent heat in PCM capsules with
relatively lower PCTs may not be effectively used. On the other hand, the non-cascaded system could suffer
from low accumulated charging ratio and much longer charging time due to the constrains of PCT. The cascaded systems especially with 5 cascaded PCTs are found to have both a fast discharging rate and a fast charging rate, and thus cascaded systems are very promising to be used as the compact high-temperature TES system using liquid as the heat transfer fluid.