What Is a Fan Coil Unit?
A fan coil unit is a device for air conditioning that generally consists of a heat exchanger (coil), air filter, and fan motor unit.
Cold or hot water sent from the main unit through piping is used to adjust room temperature and humidity through the heat exchanger, and dust is removed by the air filter and sent to the air conditioning area by the fan motor unit.
This is a relatively small and simple air conditioning unit and is also called a fan convector, especially in the case of a dedicated heating unit.
Uses of Fan Coil Units
They are generally installed and used in offices, hotels, hospitals, schools, and large commercial facilities. The most common type of fan coil unit is a square vent air conditioning unit installed in the ceiling of each room.
Fan coil units are mainly used for indoor temperature control, while the air conditioning unit (AHU) is used to communicate with the outside air. The air conditioning and heating systems for the entire building are unified and are often used for overall air conditioning purposes rather than for individual needs.
Principle of Fan Coil Units
Air conditioners consist of an indoor air conditioning unit and an outdoor unit accompanied by a fan, which operates in pairs, and each air conditioner is used for different purposes such as cooling, heating, and dehumidification. On the other hand, the fan coil unit air-conditions cold or hot water sent from the main unit through piping via heat exchangers in each room unit, so the type of air-conditioning for the entire building is determined.
They are often used in large commercial facilities, hotels, hospitals, etc., where the purpose of air conditioning the entire building is fixed and can provide heating and cooling more efficiently and economically through centralized control than by installing individual air conditioners in each room.
Recently, fan coil units have been used in combination with air conditioners, taking advantage of their compactness and simplicity. The fan coil unit performs load control in the perimeter zone near exterior walls and windows, while the air conditioner performs temperature control in the interior zone.
Types of Fan Coil Units
Fan coil units are available in 2-tube, 3-tube, 4-tube, standard motor-equipped, and energy-saving motor-equipped types.
1. 2-Tube Type
With only one coil, the cooling and heating water is switched as necessary between the heating and cooling seasons. It is relatively inexpensive, requires fewer pipes, and takes up less space.
2. 3-Pipe Type
This type has a hot water coil and a cold water coil and has only one cold and hot water return pipe.
3. 4-Pipe Type
There is a hot water coil and a cold water coil, and the number of pipes is large. It is used in rooms that need to switch between heating and cooling during the day. It is finely adjustable, but more expensive to install and operate than 2-pipe or 3-pipe systems.
4. Standard Motor-Equipped Type
This type is equipped with an AC motor and can be installed according to the space and application of the building. The main installation methods include floor-mounted type, ceiling-suspended type, ceiling-recessed type, and ceiling cassette type.
5. Energy-Saving Motor-Equipped Type
This type is equipped with a DC brushless motor. The environmentally friendly energy-saving motor reduces carbon dioxide (CO2) emissions, and the low air volume saves power consumption and reduces running costs. Installation methods include floor-mounted exposed type, floor-mounted concealed type, ceiling-suspended concealed type, and cassette type.
Structure of Fan Coil Units
Fan coil units are available in a variety of configurations, including double-floor-blowout, duct-connected, wall-mounted, floor-mounted, ceiling-suspended, and ceiling-mounted cassette types.
1. Double-Floor Blowout Type
Warm or cold air is blown out from inside the double-floor unit and is used in double-floor rooms such as computer rooms.
2. Duct Connection Type
The unit can be connected to ducts and installed in any desired location.
3. Wall-Mounted Type
This type is mounted on the wall.
4. Floor-Mounted Type
This type is used by placing it on the floor.
5. Ceiling-Suspended Type
This type is used in warehouses and other locations where the ceiling framework is exposed.
6. Ceiling-Mounted Cassette Type
Installed in the ceiling, this type has an outlet and an intake on the surface.