FCU externally very similar to the indoor units of split systems. Water-cooled blocks (chillers) perform function of external unit. They use water instead of freon. Boiler provides mode of heating air.
Today market offers cassette devices for two-pipe or four-pipe system of air-conditioning. Their power varies from 1 to 20 kW.
Companies produce a large number of different FCU, including ceiling-mounted, floor-mounted or cassette devices, etc.
FCU and chiller provide the independent temperature stabilization simultaneously in several rooms in a single building. Therefore, hotels or offices with many rooms they use very often.
They provide automatically switched on/off and change of the heating and cooling modes.
The device includes heat exchanger with a fan, a filter and built-in or external remote control.
The fan pumps air from the room into the coil of the heat exchanger for its heating or cooling. Central conditioner can also to pump a small amount of fresh air to the device. Moreover, FCU together with chiller also solve the ventilation problem.
This system is mounted on the ceiling, wall or floor on distance 8-12 in. Open-frame units can be installed behind decorative panels or false ceilings. For example, the design of cassette models often includes a decorative grille.
FCU have one or two heat exchangers in two-pipe or four-pipe models for hot and cold refrigerant.
Models with two heat exchangers use a hot water from the central heating system for first heat exchanger and a coolant from the chiller for second heat exchanger. Four-pipe FCU often are installed under the windows and perform the function of a central heating radiator in winter.
FCU chiller system has a great flexibility at the air conditioning in a large number of premises. One chiller provides connecting a large number of FCU units and air ducts for air supply from ventilation or the main air conditioner.
They operate independently of each other. Enable, disable, and change the operation mode are completely independent. Remote control provides adjusting the mode of each unit. Control console also can be mounted on the room wall. This system provides modes for each room, providing, for example, heating in one room and cooling for another room. The possibility of its gradual increase is an additional advantage. The distance between chiller and FCU is not limited, but depends on thermal insulation quality of pipelines.
Cassette FCU is the most simple. It’s designed for false ceiling. Airflow at the outlet can be distributed into four outgoing ductwork. Ducts are connected to the diffuser or ceiling grille. This solution is most optimal in offices with suspended ceilings. Ceiling FCU is mounted on the ceiling and often has a decorative housing.
Such models are often used in restaurants and cafes.
Floor standing FCUs are used in premises with two-pipe system of air-conditioning. They have decorative housing that often looks like a traditional radiator.
Standard configuration includes fans with continuously adjustable of power. Some models have a special diffusers for creating directional airflows. They eliminate the turbulence of air flows and are well suited for premises with complex configuration.
Of course, all these features affect the choice of the optimal air conditioner.
This video demonstrates a wide variety of Fan Coil Units (FCU’s) from American Pro.