Abstract: An air conditioner sucks air exhausted from an information processor, and cools down the sucked air. The air conditioner exhausts the cooled air. The air conditioner acquires a cooling state, determines whether a cooling capacity exceeds an upper limit value, and reduces the volume of exhaust air when it is determined that the cooling capacity exceeds the upper limit value. For example, the air conditioner calculates a thermal load as the cooling state by using the volume of exhaust air, a difference between the temperature of exhaust air and the temperature of suction air, and determines that the cooling capacity exceeds the upper limit value when the calculated thermal load exceeds a given threshold. The air conditioner measures the temperature of exhaust air, and determines that the cooling capacity exceeds the upper limit value when the measured temperature exceeds a set value.

Abstract: An air-conditioning system includes a ceiling plenum disposed above a ceiling of a room; an air-conditioning machine disposed in an internal space of the room; a plurality of IT apparatus mounting racks disposed in a plurality of rows, with rear faces of the IT apparatus mounting racks in adjacent two rows opposed to each other; a upper partitioning board disposed between an upper face of the plurality of IT apparatus mounting racks and the ceiling; an end-partitioning board disposed between each of ends of a space between adjacent two rows of the plurality of IT apparatus mounting racks and the ceiling; and a ceiling opening portion provided in the ceiling above a warm-air space enclosed by the upper partitioning board and the end-partitioning board. The ceiling opening portion connects the warm-air space with the ceiling plenum.

Abstract: An air conditioner sucks air exhausted from an information processor, and cools down the sucked air. The air conditioner exhausts the cooled air. The air conditioner acquires a cooling state, determines whether a cooling capacity exceeds an upper limit value, and reduces the volume of exhaust air when it is determined that the cooling capacity exceeds the upper limit value. For example, the air conditioner calculates a thermal load as the cooling state by using the volume of exhaust air, a difference between the temperature of exhaust air and the temperature of suction air, and determines that the cooling capacity exceeds the upper limit value when the calculated thermal load exceeds a given threshold. The air conditioner measures the temperature of exhaust air, and determines that the cooling capacity exceeds the upper limit value when the measured temperature exceeds a set value.

Abstract: A computer room air-conditioning system includes a temperature detection unit which is provided for each of a front and a back of each rack, and measures air temperatures of the front and the back; and a control device for acquiring a measured temperature by each temperature detection unit, and performing control based on the measured temperature. With the configuration, the control device includes a temperature difference calculation unit for calculating a temperature difference between cool air at the front and warm air at the back of each rack based on each measured and acquired temperature; and a heating element cooling control unit for controlling by adjustment an amount of flow of cool air from the underfloor space to the computer room based on the calculated temperature difference.