PURPOSE:To easily control the temperature in a green house independent of the weather and the time in a day, by attaching a refrigerator, an ice-heat accumulation tank, a refrigerant-water heat-exchanger and a hot-water tank to a green house furnished with a heat-exchanger. CONSTITUTION:A heat-exchanger 2 is attached to the inner side wall of a green house 1, a heat-exchanger 3 is placed in a seedling-raising chamber of the green house and an air-conditioning system is constructed with the green house 1 furnished with a heat-exchanger, a refrigerator 5, an ice-heat accumulation tank 4, a refrigerant-water heat-exchanger 3 and a hot-water tank 6. The refrigerator is operated by midnight electric power to form ice in the ice-heat accumulation tank 4 and a part of exhaust heat from the refrigerator 5 is stored in the hot-water tank 6. When the temperature in the green house rises in the daytime to necessitate the cooling of the chamber, chilled water in the ice-heat accumulation tank is passed through the heat-exchanger 2. When the temperature in the green house becomes low in rainy weather or in night, hot water in the hot water tank is passed through the heat-exchanger 2. When the hot water in the hot water tank is deficient, the refrigerator is operated and water is heated with the exhaust heat.
