“…So far, the preparation of PCMs using spherical 14,15) and mesh-shaped 16) copper and system analysis [9][10][11][12][13] have been conducted for a high temperature system rather at over 1 000°C. These analyses concluded that natural gas consumption, enthalpy flow, CO 2 emission, cost, and exergy loss of hydrogen production were only 59.6 %, 59.7 %, 62.8%, 86.5%, and 65.8% of those of the conventional system, respectively.…”