An active carbon/ammonia AHP with a packed bed type adsorber was used as a low temperature side AHP in a multi AHP for producing cold heat energy at temperatures below 253 K. Its heat and mass transfer characteristics in the adsorber were experimentally investigated in the assumed practical regeneration temperatures (343-363 K) and heat sink temperatures (273-283 K). Then, the heat and mass transfer model in the packed bed was evaluated by the experimental data of adsorption amount and temperatures in the adsorber. The results from the changes of adsorption amount have shown that the amount of ammonia vapor adsorbed in the adsorption process can be completely desorbed, and the reversibility between adsorption and desorption in the AHP has been proven. As in the condition of pressurization (greater than or equal to0.1 MPa), the adsorption/desorption rate of the active carbon/ammonia AHP is larger than that of the silica gel/water AHP. Subsequently, the results of cold heat output illustrated that the adsorption/desorption can be performed equally in the axial direction of the packed bed even if the packed bed height reaches as high as 100 mm.