The fresh volume of the air-conditioning area is determined in accordance with the maximum amount of fresh air needed to dehumidify the fresh air, the sum of the volume of fresh air needed to maintain the air pressure in this area. air conditioning and depleted air compensation and fresh air volume required by personnel; “Dehumidification is performed by a fan coil, so the fresh air volume is selected according to the larger fresh volume needed to maintain the air pressure in the air conditioning area and the exhaust air and fresh air the amount of air required by the staff