Discomfort elements

In addition to the calculation described above, in seeking en-

vironmental well-being, we must also take into account the

thermal discomfort caused by other factors: discomfort due to

draughts, the vertical difference in air temperature, the tempera-

ture of hot or cold floors, the temperature of hot or cold walls

and the temperature of hot or cold ceilings.

It is advisable to maintain these parameters below:

- draught speed <0.3 m/s

- vertical difference of air temperature < 5 °C

- floor temperature between 19 °C and 29 °C

- temperature difference of a hot wall from the other structures

< 23 °C

- temperature difference of a cold wall from other structures <

10 °C

- temperature difference of a hot ceiling from other structures

< 5°C

- temperature difference of a cold ceiling from other structures

< 14 °C

Radiant systems

Unlike traditional convection systems that change the tempera-

ture of the air, radiant systems are characterised by an emission

of energy by a warm emitter system to a cold absorber system.

A fundamental characteristic of these systems is that the flow

of heat emitted by irradiation is much higher than emitted by

convection which, though minimal, still exists, as we see in the

points that follow. The exchange of energy between two bodies

with different temperatures does not affect the air but only the

two surfaces involved. In fact, an underfloor system exchanges

heat with the surrounding structures such as walls, windows,

ceilings, etc. This causes an increase in the surface temperature

of the surfaces and benefits the mean radiant temperature men-

tioned previously.

To achieve comfort, it should be considered that, in addition to

exchanging or subtracting heat from the surrounding surfaces,

the system also acts on the occupants of a space.

Among the various advantages of a system of this kind, we can

point to the absence of air movement, the modularity of the sys-

tem, the quality of the comfort - given that we can change only

the temperature of the structures without changing the air tem-

perature - and the uniformity of heat distribution.

Not least, a great advantage of irradiation is on large volumes,

where we do not warm or cool the entire volume of air, but only

exchange heat with the surfaces, with obvious energy saving.

Vertical difference of air temperature

Percentage of dissatisfied based on the temperature

of the floor

Percentage of dissatisfied based on the temperature

difference between air and ceilings or walls

2- cold wall

1- hot ceiling

3- cold ceiling

4- hot wall

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Underfloor Radiant Systems - Product Guide

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