Belimo NMV-D2M - Formulae

46
4A1PC-T V2.1 NMV-D2M-EN 11-02-04.doc PM VAV - Subject to technical changes
VAV – Module NMV-D2M
N-D2 Formulae
- Formulae for converting units
m
3
/h -> l/s Volumetric flow [m
3
/h] / 3.6
m
3
/h -> cfm Volumetric flow [m
3
/h] / 1.6990107955
l/s -> m
3
/h Volumetric flow [l/s] * 3.6
l/s -> cfm Volumetric flow [l/s] * 2.1188800033
cfm -> m
3
/h Volumetric flow [cfm] * 1.6990107955
cfm -> l/s Volumetric flow [cfm] / 2.1188800033
- Formulae for calculating area
Area, circle A = 0.785 x d
2
Area, rectangle A = l x b
- Formulae for calculating volumetric flow
Volumetric flow [m
3
/h] = (A [m
2
] x V [m
3
]) x 3600
- Formulae for calculating velocity
Velocity [m/s] = Volumetric flow [m
3
/h] / Area [m
2
]
- Formulae for volumetric flow and differential pressure
- Volumetric flow [m
3
/h]
c - Constant differential pressure sensor,
manufacturer‘s value, see manufacturer’s data
- Differential pressure from measuring orifice (cross, bar) [Pa]
- Density [kg/m
3
]; 1.2 kg/m
3
at 1013 hPa and 20°C
- Formulae for pressure calculations
1 mbar = 0,001 bar = 100 Pa
1 mmH
2
O = 9,80665 Pa
V

p


V


p
c


=
p

=
2









c
V

