Menu Q Vent - Wohler DC 100PRO Bedienungsanleitung

4. Menu Q vent.

The conversion formula for determining the ventilation loss according to
equation 4.1 is stored by the measuring instrument. This value is directly indi-
cated on the display after the measurement.
The ventilation loss qLSNorm (according to equation 4.1) can, however, be
calculated easily with the help of a simple pocket calculator. Only the flow
velocity and the temperature in the exhaust-gas outlet are required for this:
· v (30 sec)· ρ
A
q =
v
LSNorm
with:
q
LSNorm
A
v
v
(30 sec)
ρ
Air
c
pL
ϑ
Air
ϑ
Room
ϑ
ext ACTUAL
ϑ
extREF
Q
load
The last term in equation 4.1 reduces the effect of the outside temperature on
the result. Without this standardization to a reference temperature of 15 °C, a
low outside temperature
losses, since the thermal lift is increased.
The following example describes the procedure with the help of a pocket
calculator.
Example: Diameter of the exhaust-gas line = 0.15 m
(cross-section area 0.0177 m2), 30 sec. after burn-out:
Residual flow = 0.61 m/s, residual temperature = 85 °C, outside temperature
= 0 °C, type of boiler: Viessmann 13211, year of construction: 1981, 26 kW,
with burner: Brötje 0-110, 1976, performance = 26 kW.
60 Hotline: +49 2953 73-211
- ϑ
· c · (ϑ
air pl air room
Q
load
ventilation loss, in %
cross-section area of the exhaust-gas line, in m
flow velocity in the exhaust-gas line, in m/s
density of air, standard: 1.2 kg/m
specific thermal capacity: 0.279 Wh/kg°C
air temperature in the exhaust-gas outlet after 30
seconds, in °C
air temp. in the heating equipment room, in
outside temperature, actual value, in °C
reference outside temperature, 15°C
set firing performance or boiler output, in W
ϑ
would inevitably lead to higher ventilation
extACTUAL
Fax: +49 2953 73-250
) 273 + ϑ
extACTUAL
273 + ϑ
extREF
3
Wöhler DC 100
PRO
(Equation 4.1)
2
C
°
(Equation 4.2)