It is investigated whether the application of the heat storage system with metal hydride (MH) is available for air conditioning of buildings or not. The trial system is composed of two heat storage vessels which is a "shell and tube type" heat exchanger with heat transfer fins and is filled with MH, and a compressor equipped for hydrogen transfer. The metal hydride generates heat at absorption process and absorbs heat at desorption process. The system proposed in this paper is simple because the vessel has two functions of heat source and heat storage, and suitable for environment because of no chlorofluorocarbon (CFC). In this paper, the performance of the heat storage vessel is evaluated experimentally by heat storage capacity, which is determined with heat quantity of cold water obtained by the transfer of hydrogen. As a result, cold water at 7°C is supplied for about 6 hours, and the capacity per unit vessel volume is 344MJ/m3 that is sufficiently high compared with the conventional system using water and/or ice.
