Effect of regeneration conditions on the adsorption dehumidification process in packed silica gel beds

The amount of energy consumption is considered to be responsible for the coefficient of performance (COP) of most air-conditioning system. The objective of this study is to evaluate the commercial silica gel and the silica gel with improved transport properties used in the adsorption dehumidification process. Effects of the regeneration temperature and the regeneration time for the specific moisture uptake in the adsorption dehumidification process using the commercial and the modified silica gels were observed. The dynamic adsorption experiments were conducted to measure the moisture breakthrough curves of the silica gels, and the moisture uptakes on the silica gels were calculated from the breakthrough curves. A temperature controlled heat source was used to carry out the regeneration of silica gels in this study. Since the solar energy with low energy density was applied to regenerate the adsorption dehumidification systems frequently, temperature of the heat source was controlled in less than 100 °C. Since the switch of the absorption process to the regeneration process is selected at the breakpoint usually, the effective uptake defined in this study is calculated from the initial to the breakpoint at a ratio of the effluent concentration to the initial concentration of 0.15. Similar effective uptakes of the system using modified silica gels regenerated at 90 °C for 0.5 h and the system using commercial silica gels for 3 h regeneration were found. Compared to the system using commercial silica gels, the system using modified silica gels has a good energy saving in regeneration.