15 / 68
-30
33°C
34
32
30
28
26
22
20
25°C
-20 -10
Temperature
at head level
Temperature
at feet level
0
10
20
30
40
50
24
Analyses of the behaviour of vehicle occupants have
identified the average comfortable temperatures.
The designers of air heating and cooling systems use
these values to define the characteristics and design
of their systems.
The following figure illustrates the need to adapt
average foot and head temperatures to the tempe-
rature outside the vehicle.
80
60
40
20
0
35
32
29
27
24
21
0
10
20
30
40
50
60
70
100
Note that, in winter, the difference between the head
and foot temperatures produced by the system is
greater, in order to achieve optimal comfort for the
occupants.
13
6.2. Physiological comfort
The notion of physiological comfort is highly subjective.
Nevertheless, our perception of hot atmospheres is
determined by the temperature and the humidity of
the air.
The definition of comfort refers to certain combinations
more often than others.
For example, dry air is more comfortable than humid
air. This is the perfect example of apparent temperature.
The figure below illustrates how humidity influences
our perception of temperature, and therefore, of our
comfort.
Perceived
Temperature (°c)
Humidity (%)
Temperature (°c)
Heat distribution versus seasons
Human perceived temperature versus humidity