Working Principle of Fan Coil Unit and Installation Precautions

1. Working Principle of The Fan Coil Unit

The fan coil unit mainly relies on the forced effect of the fan to heat the air as it passes through the surface of the heater, thus strengthening the convection heat exchanger between the radiator and the air and quickly heating the air in the room.

The fan coil is the terminal device of the air conditioning system, its working principle is to continuously recirculate the exposed air duct in the unit.

The air in the room is cooled (heated) after passing through the cold water (hot water) coil to keep the room temperature constant.

Usually, it is processed by the fresh air unit and sent indoors to meet the demand for fresh air volume in the air-conditioned room.

2. Composition

According to the number of rows of pipes, central air conditioning fan coils can be divided into two-row pipes, three-row pipes; two-pipe pipes, and four-pipe pipes: two-pipe pipes, that is, ordinary fan coil units use cold water for cooling in summer, and hot water for heating in winter;

Four-pipe fan coil units are mostly used in some more luxurious places.

They can carry hot and cold water at the same time, that is, some rooms can be cooled and some rooms can be heated according to needs.

The two rows of pipes are one pipe for cold water in summer and one pipe for cold water discharge in winter.

One pipe injects hot water and the other pipe outputs hot water; the three-row pipe means two pipes inject water, one pipe injects cold water, one pipe injects hot water, and one pipe outputs water at the same time.

3. Environmental Requirements

1. The inlet cold water temperature of the fan coil unit should not be lower than 5°C, otherwise it may cause condensation in the unit; the inlet hot water temperature should not be higher than 80°C (60°C is commonly used), otherwise it may cause the unit’s heat exchanger to Corrosion of copper pipes.

2. It is recommended that the operating environment temperature of the fan coil unit is 16~36℃ when supplying cooling and 10~30℃ when supplying heat; the relative air humidity is ≤90%.

3. The fan coil unit is only used as a comfort air conditioner and should not be used on special occasions.

4. Do not install the fan coil unit in an area with corrosive gas.

When selecting a fan coil unit, the following factors should be considered:

Cooling capacity: Generally calculated according to the cooling load of 180~250W/square meter.

Air volume: This factor will affect the number and speed of indoor heat exchange.

Static pressure: Common ones are 12Pa for household use, 30Pa for commercial use, and 50Pa for occasions where the floor height exceeds 5 meters.

Noise: The smaller the static pressure, the smaller the air volume, and the smaller the noise value.

4. Connection method:

At present, most fan coil units are limited to left and right connections when leaving the factory. Facing the air outlet, the connector is on the left, and vice versa.

Installation method: horizontal concealed fan coil unit, vertical exposed fan coil unit, ceiling cassette fan coil unit, etc.

The fan coil unit is an ideal end product for central air conditioning. It consists of a heat exchanger, water pipes, filters, fans, water trays, exhaust valves, brackets, etc. Its working principle is to continuously recirculate the air in the room where it is located. The air is cooled (heated) by passing it through a cold (hot) water coil to keep the room temperature constant.
Usually, the fresh air is processed by the fresh air unit and then sent indoors to meet the fresh air volume needs of the air-conditioned room.

5. Composition:

Central air conditioning fan coil units can be divided into two rows of pipes, three rows of pipes, and two-pipe and four-pipe pipes according to the number of rows of pipes.

Two-pipe fan coil units, that is, ordinary fan coil units, use cold water for cooling in summer and hot water for heating in winter.

Four-pipe fan coil units are mostly used in some more luxurious places. They can use hot water and cold water at the same time, that is, they can cool some rooms according to needs. Room heating.

The two-row pipe means that in summer, one pipe brings in cold water and one pipe brings out cold water.

In winter, one pipe brings in hot water and one pipe brings out hot water.

The three-row pipe means that two pipes bring in water, one pipe brings in cold water one pipe brings out the hot water, and one pipe brings in hot water at the same time. Pipe out water.

6. Principle:

The fan coil mainly relies on the forced effect of the fan to heat the air as it passes through the heater surface.

This strengthens the convection heat exchanger between the radiator and the air and can quickly heat the air in the room.
The fan coil unit is the terminal device of the air conditioning system. Its working principle is continuous recirculation in the unit, with exposed air ducts.

The air in the room is cooled (heated) after passing through the cold water (hot water) coil to keep the room temperature constant.

Usually, it is processed by the fresh air unit and sent indoors to meet the demand for fresh air volume in the air-conditioned room.

Scroll to Top