Abstract
Researches on hydration/dehydration calorimetry of zeolites and on zeolite heat pump systems have been reviewed. Hydration heat of zeolites can be used for heat exchange in a heat pump system without any fuels or electricity. Reversible heat exchange or heat storage of the zeolite/water system have been tested extensively so as to use zeolites as heat exchange absorbents and water as an absorbate. The simple but physicochemically unique combination of zeolite and water of the system is attractive for environmental safety, and for effective use of low temperature heat sources such as solar energy and waste heat from factories. However, hydration mechanisms of zeolitic water are so complicated that some confusions are found even in basic researches which are thus necessary to explore optimum zeolites suitable for the heat pump system.
