Hydrogen absorption performance investigation of a cylindrical MH reactor with rectangle heat exchange channels

A novel cylindrical metal hydride (MH) reactor embedded rectangle heat exchange channels (RHEC) was proposed in this work. The hydrogen absorption of RHEC was studied and compared with the longitudinal finned single-tube reactor (LFST) and multilayer finned single-tube reactor (MFST). The results indicated that the charging time for 90% saturation for RHEC decreases by nearly 40% and 38% compared with LFST and MFST, respectively. Then, a performance improvement method from heat transfer to structure is applied to further enhance the hydrogen absorption of RHEC. According to the bed temperature distributions, the MH bed in RHEC can be separated as three areas along radial direction. The central region and extended region are in poor heat transfer, while the near channel region possesses better heat transfer. Therefore, the heat transportation in central region and extended region need to be improved. It was found that the decrease of slant angle of heat exchange channels has nearly no effect on mean absorption performance, but can significantly accelerate the heat transportation in central region. Besides, interlaced fin layout can further accelerate the heat transportation in reaction bed compared with parallel fin layout. Moreover, adding metal foam in heat exchange channels can enhance hydrogen absorption remarkably.