The heat release and recovery characteristics of a CaO/CaCO3 type high temperature chemical heat pump were investigated experimentally by using a packed bed reactor with a single pipe heat exchanger. It is verified that carbonation of CaO has the ability to upgrade the temperature of the bed, and the generated heat energy can be recovered by air. The upgraded temperature can be controlled by adjusting the pressure of CO2. The amount of heat recovered (Q) increases with increases in air flow rate and CO2 pressure. There is an optimum value of particle size for Q.