Delta OHM HD32.3, Руководство по эксплуатации

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HD32.3
- 6 -
V1.4
2. WORKING PRINCIPLE
Microclimate term means the environmental parameters that influence the thermal exchanges be-
tween the being and the environments inside limited places and that determinate the so-called
“thermal well-being”.
The micro-environmental weather factors together with your own job influences a series of your
biologic responses connected to well-being situations (Comfort) or thermal uneasiness
(Discom-
fort).
In fact, the human body tries to keep the thermal balance in equilibrium conditions in order to keep
the body temperature on optimal values.
HD32.3 detects the following sizes:
During the visualization of WBGT index :
•
t
nw
: wet bulb with natural ventilation temperature probe
•
t
g
: globe thermometer temperature
•
t
a
: ambient temperature
During the visualization of PMV index :
•
v
a
: air speed
•
t
g
: globe thermometer temperature
•
t
a
: ambient temperature
•
rh : relative humidity
In addition to the direct measurements made with the probes connected to the instrument can di-
rectly calculate and visualize, in WBGT measurement, the
WBGT index in presence or absence
of solar radiation , in the PMV measurement, the medium radiant temperature t, the Predicted
Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD).
2.1.1 WBGT Index
WBGT (Wet Bulb Globe Temperature) - wet bulb and globe thermometer temperature - is one of
the indexes used for determining the thermal stress to which is submitted a being in a warm envi-
ronment. It represents the value, with reference to the metabolic waste connected to a special job,
over which the being is in a thermal stress condition. WBGT index combines the temperature meas-
urement of natural ventilation wet bulb
t
nw
with the Glob thermometer t
g
and, in some situations,
with the air temperature t
a
. The formula for the calculation is the following one:
•
inside and outside the buildings in absence of solar irradiation:
WBGT
close environments
= 0,7 t
nw
+ 0,3 t
g
•
outside the building in presence of solar irradiation:
WBGT
external environments
= 0,7 t
nw
+ 0,2 t
g
+ 0,1 t
a
where:
t
nw
= wet bulb temperature with natural ventilation
t
g
= globe thermometer temperature;
t
a
= air temperature.