As a new technology for effective utilization of electric energy, a chemical heat pump unit for night electric heat-storage and cold/hot heat-recovering in daytime air-conditioning/hot-water-supply is proposed and a prototype is made. The basic heat-releasing characteristics and the effects of reactant particle amount and heat recovering condition on the characteristics are studied experimentally. It is found that the electric energy stored as densely as 1.86 MJ/kg-CaO in the form of thermochemical energy is released in the form of thermal energy as cold heat at around 273 K and hot heat at around 500 K. The heat is recovered as cold heat for air-conditioning at around 275 K and hot-water at around 350 K. The total amount of reactant particles should be determined with a balance of heat-loss, although heat releasing is improved by using a shallow bed with a small amount of particles. Furthermore, the recovered heat amount is found to be enlarged because of increased reactivity of reactant particles when the heat-recovering rate is properly controlled.