What is radiance?

Directly from the Sun a natural, flexible and cheap heating way

In a lovely winter day, passing from a shade zone to a sunny one, we get an immediate feeling of warmness. This means that it is not the air, which has a constant temperature everywhere, that causes heating but it is rather the direct exposure to sunlight. This natural propagation of heat is called radiance and consists in the transmission of the long and soft waves of infrared rays contained in the spectrum of the Sun's electromagnetic energy.

The properties of infrared rays are:
1. They are propagated in straight lines, in all directions and they are reflected only by some materials;
2. they propagate naturally in vacuum without no need of additional energy;
3. they are not absorbed by air;
4. hey are absorbed by the solid bodies that transform them immediately into thermal power.

Radiance is today at heart of the most advanced air conditioning technologies: not only for the recent domestic radiant system for small environments, but for the most consolidated applications for the heating of large industrial areas. The emitting surfaces are hanged to the ceiling of the room to be heated, so that the floor, machines and persons to be heated are contacted directly and without dispersion. Depending on the area to be heated, the various heat emitters are distributed over the area so as to obtain uniformity in the heat flow.

Advantages of the radiant heating respect to the convection heating

In the same conditions of comfort, a radiant heating system offers the following advantages as compared to a convection system

Greater comfort with lower air temperature

The perception of comfort in a room is not only connected to the air temperature (TA) (as usually thought), but also to the surfaces that surround the body (Average radiant temperature TMR)

In the graphic are analyzed the conditions of comfort for the workers in an industrial premise, employed by the tool machines, with medium grade clothes and air speed in the room not higher than 0,5 m/s. In presence of a convective system, the comfort can be obtained with an air and wall temperature of 17°C; using a radiant system, the air temperature can be decrease of 15°C, keeping the average radiant temperature at 22°C.

Lack of thermal gradient resulting in reduced dispersion

In rooms heated with radiant systems, the lack of a marked thermal gradient reduces air layering and therefore also the thermal load required to heat the room.

The figure at side shows the air temperature when varying the height of a building with convective heating and one with radiant heating. It can be seen how, in the convection system, thermal layering leads to very high temperatures in the upper part of the room, thus creating substantial increase in dispersion. In the radiance system, the heat is instead concentrated in the lower part of the room, without heating the air near the ceiling. For this reason, radiance heating is installed with especially successful results in building of considerable height.

No air movement, hence lack of suspended dust particles

In convection systems, dust and any other particles which may or may not be harmful due to manufacturing processes are constantly held suspended in the air due to the ventilation which is typical of those kinds of systems.

In radiant systems there is no air movement. This makes the adoption of radiant systems in any building with any manufacturing process the perfect choice. It is up to the designer to choose the most suitable system based on the characteristics and activity performed in each single room.

Well-being and respect for the environment

An industry interested in protecting the environment and the well-being of its human resources must adopt an industrial heating system working in two directions: reduce noxious emissions into the atmosphere and ensure the greatest comfort of the work site, the environment where we spend more than a third of our day. Heat is produced in radiation systems by gas generators: gas is known to be a clean energy with combustion residues having a low environment impact. Where we work is where we can consider the advantages of this technology:
- no fluids in movement means no harmful currents and no movement of dust;
- the small temperature differences between high and low areas reduce heat layers in the air and condensate developing on solid bodies;
- no forced warm air helps to maintain the right amount of oxygen.

Low thermal inertia

The CARLIEUKLIMA radiant systems generally have a low thermal inertia, which allows them to be brought up to full operating power quickly, thus reducing their operating times compared to a convection system.

Possibility to heat by zones

It is possible to heat single zones or workstations without having to heat the entire area. It is also possible to control ambient temperature zone by zone. Large operative spaces are organised according to functions: management areas, production areas, warehousing space, passages. Each of these components - organically connected to the rest of the system - has its own identity even in terms of energy requirements. For example, a production department with operators requires a constant comfortable temperature that is not needed in a passage. Different conditioning needs can often be in strong conflict with the physical arrangement of workstations, differentiated in terms of function, but contained in one environment without separating and insulating elements. In cases such as these, the application of traditional heating techniques can be dispersive and inefficient: too much heat where do don't need it, too little where you do. Today the new radiation technologies allow to overcome these limits once and for all, when suitably enhanced by strategic engineering in order to optimise the three components of these systems: generators, radiating lines, electronic devices.

Fuel savings

One of the strengths of the radiant heating technique is the huge savings that it makes possible. Improved performance compared to systems with the same power levels with clear savings (even more than 45%) in fuel consumption thanks to:

- less dispersions caused by a lower air temperature;
- less dispersions caused by the lack of thermal stratification;
- less working time of the system, thanks to a low thermal inertia;
- possibility to heat by zones, starting the system only when necessary.

The speed with which the system can be brought up to full operating power and the extremely low maintenance costs complete the economic picture of CARLIEUKLIMA system operation.

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