The fancoil is one of the elements that make up a refrigeration or air conditioning system. This is responsible for recirculating the air in a heated space through a fin-shaped coil, inside which hot or cold water circulates. Consequently, the heat transfer between the air and the coil is faster and more efficient, to air-condition or cool a given space.
How does a fancoil work?
The fancoil is a rectangular closed structure, inside which there is an electric fan, a fin-shaped coil, and a particle filter. The fancoil electric fan creates a strong current of air inside the structure, sucking in air at one end and blowing it out at the opposite end.
Hot or cold water circulates inside the coil, coming from the primary circuit of a boiler, heat pump, or cooling system. The air driven by the electric fan passes through the external fins of the coil, and heat is exchanged or transferred between them. For this reason, the fancoil is known as a water-air exchanger, since water is the element that transfers or absorbs heat into the air.
The air filter is placed at the fan coil air inlet to filter particles, keeping the electric fan and coil clean. On the other hand, the coil is placed towards the end where the air comes out.
An analog or digital thermostat is used to control the air conditioning temperature. The electrical signal from the thermostat is used to turn the electric fan on or off (on/off control), or vary its speed (inverter control).
What advantages do fancoils offer?
Sometimes, it is necessary to air-condition several independent spaces, within a house or building, using a single cold or heat generation system. In this condition, there are two possible alternatives; install a network of ventilation ducts or install a fancoil in each space to be air-conditioned. The alternative of bringing refrigerant gas directly to each space has been ruled out since a lot of refrigerants would be needed. In addition, the refrigerant represents a risk to health and the environment.
The installation of a network of ventilation ducts for air conditioning is an expensive task, in many cases. However, it is more feasible to carry hot or cold water through pipes, to each of the fancoils that are going to be used.
Types of fancoil
Among the types of the water-air exchangers are those of floor, wall, ceiling, ducts, and cassette. This classification is based on the mounting site and the shape or appearance of the equipment. However, two types of fancoil are recognized, depending on their intrinsic design. These are the two-pipe fancoil and the four-pipe fancoil.
Two pipe fancoil
This equipment has a single coil or heat exchanger. Consequently, this fancoil only has one water inlet and one outlet pipe, associated with a single heat exchanger. With this equipment, you can only work in one mode at a time (heat or cold), but it is relatively less expensive.
Four pipe fancoil
The four-tube-water-to-air exchanger comes with two heat exchangers (two tubes for each heat exchanger). Therefore, one heating and one cooling circuit can work independently and simultaneously. These are more expensive pieces of equipment but at the same time more useful in situations where one space needs to be heated while another is being cooled. For this reason, these are the most suitable types of fancoils for hospitals, offices, department stores, etc.
Four-pipe fancoils can work as dehumidifiers, using the cold exchanger. In this way, it is possible to condense the excess relative humidity of the air, and then dispose of the water outside using channels and pipes.
Differences between a water-air exchanger and an Air Handling Unit
People unfamiliar with air conditioning systems may confuse these devices. For this reason, it is necessary to briefly clarify the differences between the fancoil and the AHU. First of all, the AHU is a piece of equipment designed to be installed in outer space. On the contrary, the fancoil is mounted inside the space to be air-conditioned.
The AHU and the fancoil have similarities and share some components. In other words, both units have electric fans, heat exchangers and an air filter. However, the AHU has other elements that allow it to renew part of the conditioned air that is recirculating, taking fresh air from outside. The latter is very important to keep the concentration of carbon monoxide and dioxide in the conditioned air to a minimum.
Both the AHU and the fancoil heat the air by exchanging heat with coils, inside which hot or cold water circulates.
Differences between a fancoil and a split air conditioner
Sometimes it is difficult to distinguish between a fancoil and the indoor unit of a split air conditioner with the naked eye. For this reason, it is necessary to clarify that inside the coil of the split indoor unit only refrigerant gas circulates. However, inside the fancoil coils only water circulates. That is, in a fancoil there is a heat exchange of the water-air type, but in the split air conditioner the heat exchange is of the gas-air type.