abstract |
A plurality of heat pump units each of which is composed of a first and a second heat medium receptacle and a plurality of closed vessel are provided, and means for performing heat exchange between the heat medium receptacle of one heat pump unit and the heat medium receptacle in another unit is used in operating the device. As a result, the effect of the heat capacity of the closed vessels upon the coefficient of performance is reduced, and therefore, the coefficient of performance of the device increases. |