System structure, classification and characteristics of fan-coil air conditioning system

The application of fan-coil unit in air conditioning engineering is mostly combined with the fresh air system treated separately. As shown in the figure, the structure of fan-coil unit consists of coil units (surface coolers, usually 2-3 rows) and fans (forward multi-wing centrifugal fans or cross-flow fans), and the air volume ranges from 250 to 2500m3/h. ..

Composition of fan-coil unit: The fan-coil unit consists of fan, motor, coil, air filter and room temperature regulator.

Devices and boxes, etc.

The working principle of fan-coil unit is that the fan in the unit circulates indoor air continuously, so that it can be cooled or heated continuously through the coil supplying cold water or hot water to keep the indoor temperature. Among them, the function of air filter is to filter the dust in indoor circulating air, improve the sanitary conditions of the room, and at the same time, it can protect the coil from dust blockage to ensure the air volume and heat exchange effect.

The main advantages of fan-coil air conditioning system are: low noise, suitable for hotel rooms; It has the superiority of individual control; Easy to adjust and control the system partition; The fan coil unit itself is small in size and easy to arrange and install.

The main disadvantages of fan-coil air conditioning system are: because the unit is located indoors, it needs to cooperate effectively with buildings and other types of work; The units are relatively scattered, and the maintenance workload is heavy; We must solve the problem of fresh air; The static pressure of the fan is small, so it is impossible to use high-performance filters, which leads to low indoor air cleanliness.

What are the characteristics of fan coil units? There are two types of fan coil units: vertical and horizontal, and there are two installation methods: hidden and exposed. From the structure of fan coil, its main characteristics are: centrifugal multi-blade fans are mostly used, the impeller diameter is generally below 150mm, and the static pressure is below 100Pa, and the impeller material is galvanized steel plate, aluminum plate or ABS engineering plastic; Capacitive motors are usually used. When running, you can change the speed of the motor through the speed switch to change the air volume of the fan. The ratio of high, medium and low gears is about 1: 0.75: 0.5. Coils are usually made of corrugated copper tubes or slotted aluminum plates. Generally, the outer diameter of copper tube is 65,438+00 mm, the wall thickness is 0.35mm, the thickness of aluminum sheet is 0.65,438+02 ~ 0.65,438+05 mm, and the spacing between sheets is 2 ~ 2.3 mm The tube expanding process is adopted in the process to ensure the close contact between copper tube and aluminum fin and improve the thermal conductivity. The number of rows of coils is two columns. The filter material of the air filter is made of coarse-pore foam plastic, fiber fabric or nylon braid. In practical engineering, fan-coil units are widely used in rooms, offices and other buildings because of their flexible control and low noise. Fan coil unit mainly provides indoor heat and humidity load, and fresh air is treated by other equipment.