Fan Coil Systems

FAN COIL SYSTEMS

Definition

A fan coil unit (FCU) is a simple device consisting of a heating and/or cooling heat exchanger or 'coil' and fan.

A fan coil unit is a device used to control the temperature in the space.

It is controlled either by a manual on/off switch or by a thermostat.

Construction

Fan coils contain (Fig. 2.12)

• outdoor air mixerved

• fan

• heating coil

• cooling coil.

The fan coil unit is connected to either a hot water loop or a chilled water loop through heating or cooling coil respectively.

Working

• A fan coil unit (FCU) contains a fan which draws the air gnits into the unit then blows it over a cooling or heating coil.

• The air comes out of the FCU either cooler or hotter

FCUS can introduce proportion of fresh air that is mixed with the recirculated air.

Typically an individual FCU serves only up to 150 m².

FCUS generally have a chilled water coil for cooling and a hot water coil or an electric heating for heating element.

Types of fan coil unit:

Fan coil units are classified into two types

1. Two-pipe fan coil units

Two-pipe fan coil units have one supply and one return pipe. The supply pipe supplies either cold or hot water to the unit depending on the time of year.

2. Four-pipe fan coil units

Four-pipe fan coil units have two supply pipes and two return pipe. This allows either hot or cold water to enter the unit at any given time. The four-pipe fan coi fan coil unit is most pogailooo To gaitsed niguordt gool 1918w bellido 8 commonly used.

Advantages

• Individual control for zone or office, including heating in some zones and cooling in others

• Relatively low cost of standard units

• Simple control system

• Built in standby capacity where several units are located in one zone.

 Disadvantages

• A Limited flexibility with standard units - all operating parameters fixed by the manufacturer.

• Normally only simple dry bulb control is provided, although some specialist units incorporate electronic boxim control systems and humidifiers.

• Limited control of fresh air input.

• Limited ability to control air distribution.

• Visibility of the units and connecting chilled water  services may be an issue.