First, the central air conditioning refrigeration principle: there are compression, absorption, etc.; Second, the principle of central air conditioning system: working principle of windy system, working principle of water system, working principle of coil system, etc., briefly introduced as follows: When the central air-conditioning fresh air system works, the outdoor fresh air is attracted to the wind cabinet by the wind treatment machine, and is filtered and cooled and dehumidified, and then sent to each room by the air duct. At this time, the fresh air can not meet the indoor heat and humidity load, and can only meet The amount of fresh air required in the room, as the indoor fan coil handles the indoor air heat and humidity load, the excess air is discharged to the outside through the return fan according to the opening ratio of the valve, and a part is returned to the air inlet for recycling. Screen replacement kit,Curtain Mosquito Nets,Curtain Mosquito Net Roll,Fiberglass Curtain Mosquito Jinwu Glass Fiber Co., Ltd , https://www.jwglassfiber.com