To develop chemical heat pump of higher energy density and efficiency heat-release characteristics accompanied by exothermic hydration reaction in packed bed, $Ca(OH)_2/CaO$ reactor, are examined in a lab-scale unit. We have studied the enhancement effect of inserted fins in cylindical packed bed reactor. The results obtained by numerical analysis about profiles of temperature, completion time of reaction and exothermic heat amount released from the reactor read the insertion of fins in reactor can reduce the reaction completion time by half and the rate of thermochemical reaction depends on the temperature and concentration, and it is also governed by the boundary conditions and the rate of heat transfer in the particle packed bed.