Fan coils, in English fan coil unit, are devices that act as terminals to heating and air conditioning systems. It is found mainly in mixed air / water conditioning systems and are characterized by a high level of energy efficiency.
From an aesthetic point of view, there are various types, we will see some specifically, but know that there are those recessed, floor, wall, for example. And at the installation level, being often in a cabinet, we can indulge ourselves according to the furnishing needs we have. Operation is always the same. But let's see what these are then fan coils: a complex name for a rather simple device.
Fan coils: what they are
THE fan coils they consist of a metal casing in which there are one or two air / water heat exchange batteries, a fan, an air filter, a condensate collection tray. This within the fan coils which are then connected externally with the hot and / or chilled water networks but, if they are visible, they usually have a cover cabinet.
Simple, or to your liking, the cabinet hides structure, electrical connections, any command and various hydraulic connections with any shut-off valves. The integers fan coilspractically. At a friend's house, a cabinet can hide one of them fan coils, unbeknownst to you: they are camouflaged but very useful because they “spit” hot air from a grill to the delight of all, on winter evenings.
Fan coils: structure
THE fan coils they can have only one heat exchange coil or two. In the case of a single coil, they either heat or cool: at the same time they cannot do both actions because they have only two tubes and the exchange fluid, hot or cold, circulates in them. The temperature cannot be double.
With their 4 tubes, the fan coils with two heat exchange coils they can make hot fluid and cold fluid flow in their hydraulic circuits in the same period of use. Based on the desired temperature, the fluid is chosen through valves at the inlet of the coils. These fan coils, therefore, they can heat or cool.
Once there were also fan coils with three pipes, hybrids, with a single water return pipe but it was a hydraulic stunt with little gain in practice, so it did not survive as a model.
Fan coils: how they work
THE fan coils they are "all recirculation" air units, air that is taken with a fan, from the surrounding environment, and passed through a filter where the coarse dust it has with it is "left". Then it is pushed towards the heat exchange coil where it exchanges heat with water by forced convection. Finally, the air, at the desired temperature, is expelled into the room from which it was taken, giving us heat or coolness.
In case of heating, in fact, the heat is taken from the fluid, while in case of cooling it is released and, at the same time, in the convectors there is also the dehumidification. This is because it is necessary to relieve the air from the humidity that is retained during the heat exchange, the resulting water falls into the collection tank.
Fan coils: what they are for
Thanks to a fan, often electric, i fan coils they diffuse hot or cold air into the rooms, ensuring healthy air exchange and one of the most effective air conditioning possible. Generally, as we have already seen, there is a thermostat to adjust the temperature we want to obtain, as well as the valve to adjust the fan speed. A switch changes the seasons: summer / winter.
Today one of the most frequent uses for the fan coils is the one in mixed air / water conditioning systems, to control the temperature, associated with an AHU (Air Handling Unit) which deals with humidity and effectiveness of the turnover. The number of cases in which we see these terminals used for heating only or cooling only, associated with a natural, uncontrolled change of air is currently less.
In the future, everything is possible, taking into account the advantages that i fan coils offer, in terms of comfort, energy savings and healthiness of the environments. The thermal comfort is due to the recirculation of air that they are able to create, ensuring a fairly uniform temperature in the rooms, unlike radiators. Hence, even a higher level of health thanks to the presence of filters that trap impurities and prevent the walls from getting dirty.
For the energy saving, speaks of the temperature of the hot water used: 45-50 ° C. A level that allows the combination with heat generators characterized by high efficiency and medium-low working temperatures, such as condensing boilers, heat pumps and solar thermal systems. For radiators, for example, other temperatures come into play and, moreover, the latter show phenomena of heat dispersion towards the outside much greater than the fan coils, able to not give heat to the walls but exclusively to the environment to be heated.
Electric fan coils
Between fan coils electric on the market, I propose one that serves as an example, leaving all of us, myself included, free to range between the different models. I chose the portable one, with additional double ventilation, even, which heats the room very quickly.
It's a fan coil De'Longhi, available in gray and white, has no cabinet as it is portable, but an excellent design that therefore does not make you miss it, on the contrary, a specially designed grille "shoots out" the hot air so as to distribute it as evenly as possible, with a wide range.
Portable does not mean lacking in comfort, mind you, in fact this model is complete with 24 hour timer, to program daily operation, and thermostat to set the desired temperature. While being portable, if we want to fix one of these De Longhi fan coils on the wall, there are, included, hooks to do this. For semi-nomads or undecided.
Wall-mounted fan coils
Then there are the wall-mounted fan coils real, fully-fledged, for those who do not like to improvise, or for those who want to install fixed ones. An example is that of the Radialight Stylo 1000, able to "take care" of rooms up to 11-13 square meters. As a heating system this kind of fan coils uses the one based on natural convection, as already mentioned: no fan, no motor. Silence!
Entirely made in Italy, these fan coils to be fixed to the wall, they have an internal “X-Shaped” aluminum heating core designed to reach the desired temperature in the shortest possible time, with the possibility of programming everything via remote control. Important for aesthetes and architects, a clarification: they are fan coils to walls but do not require any masonry or invasive electrical connections.
Ferroli fan coil
One of the most active firms in proposing models of fan coils suitable for our environments is the Ferroli. The Ferroli are fan coils obviously equipped with a filter, easy to extract and clean, and the ability to adjust 3 fan speeds, even remotely.
De Longhi fan coil unit
Of fan coils There are so many DeLonghi that here is another one after the portable one. This is not, it has 2 selectable power levels (1000 or 2000 Watts) and is all about one more even heat distribution possible. It is the De'Longhi HS20F, white. In addition to the room thermostat and the safety thermostat, they have an antifreeze function and double insulation.
Other related articles that may interest you:
- Convectors: advantages and disadvantages
- Solar thermodynamic: how it works