Fan coil units in China have gone through several different changes. The previous understanding of the fan coil unit was mainly based on meeting the air volume requirements. The fan coil unit plus the fresh air system is divided into two parts, the central air-conditioning fan coil unit and the fresh air system. According to the external static pressure of the fan coil, it can be divided into standard type and high static pressure type, and according to the number of heat exchange coils, it can be divided into two rows and three rows.

The coil unit can be divided into water circuit and gas circuit. The cold (hot) medium water is supplied by the cold (hot) source equipment (such as a refrigerator) of the water central air conditioner, and is transported to the coil for circulating flow under the action of the water pump. The air is sucked into the room by the fan through the air return port, and then sweeps over the coil, exchanges heat with the cold (hot) medium water in the coil, cools and dehumidifies, and then sends it into the room through the air supply port. Repeat this cycle to adjust the indoor temperature and humidity. The coil plus fresh air system is divided into two parts, the central air-conditioning fan coil and the fresh air system. The coil is the terminal equipment of the central air conditioner, and the fresh air system bears the fresh air load to meet the indoor air quality. Coil plus fresh air system is an important form of water system air conditioning, and it is also a more common form of air conditioning used in private buildings. Advantages of coil plus fresh air system (compared with full air system) Advantages: 1. Flexible control, with the advantage of independent control, can flexibly adjust the temperature of each room, and determine the start and stop of the fan coil unit according to the use of the room;

With the help of the coil unit, the indoor air is continuously circulated to be cooled or heated through the coil, thereby maintaining the desired temperature and relative humidity in the room. The cold or hot water used by the vertical fan coil unit is supplied by a centralized cold and heat source. At the same time of the fan coil unit, the fresh air centrally processed in the fresh air air conditioning room is transported to each air conditioning room through the dedicated fresh air pipeline to meet the hygienic requirements of the air conditioning room. Compared with the centralized system, the coil air conditioning system has no large air pipes, only water pipes and small fresh air pipes, which has the advantages of convenient layout and installation, small building space occupation, and good independent adjustment. It is widely used in comfortable air conditioning systems with low temperature and humidity accuracy requirements, many rooms, small rooms, and independent control. The working principle of the coil is not as complicated as the central air conditioner. In fact, we can think of the fan coil unit as an electric fan, but the wind blown by this electric fan is the temperature we need. The structure of the coil unit Fan: driven by a one-way multi-speed low-noise induction system motor, by adjusting the input voltage to change the fan speed, the fan air volume is divided into three levels: high, medium and low.