The working principle of the vertical fan coil air conditioning system is to continuously circulate indoor air through the fan coil unit, cooling or heating it as it passes through the coils to maintain the required room temperature and relative humidity. The chilled water or hot water used in the coils is supplied by a centralized chilled and hot water source. At the same time, fresh air processed by the fresh air conditioning room is distributed to each air-conditioned room through dedicated fresh air ducts to meet the hygiene requirements of the air-conditioned rooms.
 
The vertical fan coil air conditioning system, compared to centralized systems, lacks large ducts and only features water pipes and smaller fresh air ducts. It boasts advantages such as easy layout and installation, minimal space occupation in buildings, and good individual control, making it widely used in situations where temperature and humidity precision is not high, there are many rooms, the rooms are small, and individual air conditioning control is required.