Abstract: When a humidity adjustment device starts up, an outside air temperature To and an room air temperature Tr are compared to determine which air temperature is higher. By mutually changing the flow of the outside air and the flow of the room air by means of an air circulation switching device, the air having the higher temperature of the outside air and the room air is circulated to a heat exchanger that operates as an evaporator.

Abstract: A humidity control apparatus performs a humidification operation in which outdoor air is supplied to the inside of a room through a moisture-desorption adsorption heat exchanger serving as a condenser and room air is discharged to the outside through a moisture-absorption adsorption heat exchanger serving as an evaporator. The humidity control apparatus includes a preheat heat exchanger which, in the humidification operation, is positioned upstream of the moisture-desorption adsorption heat exchanger in the flow of outdoor air in an air passage and serves as a condenser to heat outdoor air in a refrigerant circuit, and a heat-recovery heat exchanger which, in the humidification operation, is positioned downstream of the moisture-absorption adsorption heat exchanger in the flow of room air in the air passage and serves as an evaporator to recover heat from room air in the refrigerant circuit.

Abstract: When a humidity adjustment device starts up, an outside air temperature To and an room air temperature Tr are compared to determine which air temperature is higher. By mutually changing the flow of the outside air and the flow of the room air by means of an air circulation switching device, the air having the higher temperature of the outside air and the room air is circulated to a heat exchanger that operates as an evaporator.

Abstract: A humidity controlling ventilator includes: an air flow rate calculator configured to calculate an air volume flow rate of an air blowing fan based on a specific volume of air located downstream of an adsorption heat exchanger and an air mass flow rate of the air blowing fan; and an air blow controller configured to control the air blowing fan such that the air volume flow rate calculated by the air flow rate calculator approaches a predetermined target air volume flow rate.

Abstract: A ventilation system includes a connection determinator configured to determine that N-th, second, and sixth humidity controlling ventilation devices are connected to an identical second duct bank in a situation where when fans of the second and sixth humidity controlling ventilation devices are driven, and the rotational speed of a fan of the N-th humidity controlling ventilation device is changed, a power detector detects fluctuations in the power consumed by the fan of each of the second and sixth humidity controlling ventilation devices.