13
|
Special requirements for R32 units
Installer and user reference guide
49
BS4~12A14AJV1B
VRV 5 branch selector unit
4P695527-1 – 2022.02
pressure inside the BS unit is within the range of 20~350 Pa below the pressure of
the surroundings. We use this 115 m³/h airflow rate for further calculations.
- 42.9
115
P
INTERNAL
[Pa]
-300
-250
-200
-150
-100
0
0
50
100
150
200
250
300
-50
AFR
OUT
[m³/h]
Note:
These curves present the internal pressure of the BS unit compared to an
ambient pressure of 101325 Pa.
Use the curve of the outlet pressure (P
OUT
) in function of the airflow rate (AFR
OUT
)
for the BS unit. With an airflow rate of 115 m³/h, the resulting pressure drop
generated by the BS unit is 47.5 Pa.
-300
-250
-200
-150
-100
0
0
50
100
150
200
250
300
-50
P
OUT
[Pa]
AFR
OUT
[m³/h]
- 47.5
115
Use the curves, with instructions how to read them, of the manufacturer of the
components to find the pressure drop generated by all components in the
ductwork. A conversion of units might be required. Beware that for ducting, the
pressure drop from the manufacturer might be given per unit length of ducting
(units are for example Pa/m). Multiply this value by the duct length to find the total
pressure drop.
AFR
[m³/h]
AFR
[m³/h]
ΔP
[Pa/m]
ΔP
[Pa]
115
1
115
8
Ducting
Bends
EXAMPLE
Write down the pressure drop of each component in an overview table. Sum up
the pressure drops.
Nº
Indication
Type
AFR [m³/h]
Length [m]
∆P [Pa/m]
∆P [Pa]
1
a
BS unit
115
-
-
47.5
2
b
Duct
“
5
1
5
3
c
Bend
“
-
-
8
4
b
Duct
“
10
1
10
5
c
Bend
“
-
-
8
6
b
Duct
“
2
1
2
7
d
Expander
“
-
-
4
8
e
Duct
“
6
0.5
3
9
f
Reducer
“
-
-
6
10
b
Duct
“
2
1
2
11
b
Duct
“
1
1
1
12
g
Non-return valve
“
-
-
11
13
b
Duct
“
1
1
1
14
h
Wall grill
“
-
-
15
Total pressure drop (sum of rows 1 to 14)
123.5
