JP2992707B

PURPOSE:To obtain a cooling/heating device optimum for a district cooling and heating system employing a heat pump by a method wherein means such as heating intermediate temperature fluid or fluid in a lowest temperature tank respectively or the like is applied in accordance with a temperature in the high-temperature side heat source tank of a hot-water accumulating tank. CONSTITUTION:A cooling and heating device is provided with a hot-water accumulating tank 100, consisting of a plurality of heat accumulating layers communicated through a communicating passage 20, a low-temperature side heat pump device 43, a high-temperature side heat pump 42, a cooling and heating load, the heat source 200 of heat pumps, a heat transporting system and the like. In this case, intermediate temperature fluid, cooled by a high- temperature side heat pump 42, is heated by the heat source 56 of the heat pumps and is moved into the high-temperature side heat source tank 29 when a temperature in the high-temperature side heat source tank 29 is higher in the hot-water accumulating tank 100. On the other hand, when the temperature in the high-temperature side heat source tank 29 is low, the fluid in the lowest temperature tank 30 is heated and, at the same time, the low-temperature side heat pump 43 is also operated.