Fan coil unit (FCU) is a device consisting of a heating or cooling coil and fan. It is part of an HVAC system found in residential, commercial, and industrial buildings and used to control the temperature in the space where it is installed or also serve multiple spaces.
Manufacturers need to constantly respond to changing market demands and satisfy increasingly stringent legislation, specially energy consumption. Make sure you are using energy efficient fan coil units.
Types of fan coil units:
1. Two-pipe FCU:
It has one supply and one return pipe. It supplies either cold or hot water to the unit depending on the time of the year.
2. Four-pipe FCU:
It has two supply pipes and two return pipes. This allows either hot or cold water to enter the unit at any given time, due to differences in internal heat loss or heat gains, the four pipe FCU is most commonly used.
Fan coil units can be more economical to install than ducted 100% fresh air systems (VAV) or central heating systems with air handling units or chilled beams. Various unit configurations are available, including horizontal (ceiling mounted) or vertical (floor mounted).
Concealed or Exposed Fan Coil Unit
Exposed fan coil unitmay be wall-mounted, freestanding or ceiling mounted, and will typically include an appropriate enclosure to protect and conceal the fan coil unit itself, with return air grille and supply air diffuser set into that enclosure to distribute the air.
Concealed fan coil unit will typically be installed within an accessible ceiling void or services zone. The return air grille and supply air diffuser, typically set flush into the ceiling, will be ducted to and from the fan coil unit and thus allows a great degree of flexibility for locating the grilles to suit the ceiling layout and/or the partition layout within a space. It is quite common for the return air not to be ducted and to use the ceiling void as a return air plenum.
Advantages of fan coil units systems
The benefits provided by fan coil unit systems include the following:
• Significantly smaller ventilation plant and distribution ductwork than an all-air system.
• High cooling capacity.
• Comparatively low cost of capital equipment.
• Individual zone control of space temperature, if suitable controls fitted.
• Flexibility to accept future changes in load and space layouts.
Fan coils are particularly suited to applications with intermittent medium to high sensible cooling loads and where close humidity control is not required, e.g. offices, hotels, restaurants.
Most of these installations use units mounted in the ceiling void as they do not occupy floor space within the building, although a significant number of projects still specify vertically mounted cased/recessed units.
The basic reason for installing a fan-coil system is to provide ‘comfort conditioning’ at the specified environmental conditions within the space.