The development of an energy-supply system which is very efficient and does little harm to the environment is desirable. Adsorption heat pumps satisfy these requisites because they use low-level thermal energy as a driving force, and use safe and natural substances ; silica gels or zeolites as adsorbents and water as a refrigerant. A tube plate reactor in which adsorption and desorption take place is proposed here to make the system compact, to enhance heat transfer, and to provide increased heat storage capacity. Fundamental heat-transfer experiments are carried out. And the heat-transfer mechanism is identified through a comparison of the experiments and simulations. The concept of equivalent thermal conductivity is defined, and as a result, it is also identified, which is essential for the thermal design of the heat pumps.