In order to improve the cold production performance of adsorption chillers using an activated carbon-methanol pair, we studied a high-density molded adsorbent consisting of activated carbon fiber and polytetrafluoroethylene (PTFE). The high-density activated carbon fibers (HDACF) with an apparent density of 135–357 kg m−3 were successfully prepared by the addition of a low dose of PTFE through kneading and mechanical compression processes. Experimental results showed that the methanol adsorption equilibria on the HDACFs could be expressed by the Dubinin–Astakhov equation. The HDACF with a larger apparent density adsorbed and desorbed methanol more rapidly. It was possible to estimate the temporal changes in the amount of methanol adsorption, and the surface temperature of the HDACF for both adsorption and desorption processes using calculation model established in this study. The calculated results showed that the adsorption rate of methanol vapor achieved a maximum apparent density 380 kg m−3 for the HDACF.